Patent Publication Number: US-2023144128-A1

Title: Variable coherence adaptive antenna array

Description:
This application is a continuation of U.S. patent application Ser. No. 17/980,997, filed 14 Nov. 2022, which is a continuation of U.S. patent application Ser. No. 17/852,466, filed 29 Jun. 2022, which is continuation of U.S. patent application Ser. No. 16/318,632, filed 17 Jan. 2019 and granted as U.S. Pat. No. 11,418,240 on 16 Aug. 2022, which is a national stage application of PCT/EP2018/081226, filed 14 Nov. 2018, and claims benefit of U.S. Provisional Application No. 62/588,264, filed 17 Nov. 2017, the entire disclosure of each of which is incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to multi-antenna transmission and reception techniques and, more particularly to codebooks and precoding for spatial multiplexing. 
     BACKGROUND 
     The next generation of mobile wireless communication systems, known as Fifth Generation (5G) and Next Radio (NR), will support a diverse set of use cases and a diverse set of deployment scenarios. The latter includes deployment at both low frequencies (100s of MHz), similar to Long Term Evolution (LTE) today, and very high frequencies (millimeter waves in the tens of GHz). 
     5G and NR will support multi-antenna techniques that significantly increase the data rates and reliability of a wireless communication system. The performance is in particular improved if both the transmitter and the receiver are equipped with multiple antennas, which results in a multiple-input multiple-output (MIMO) communication channel. Such systems and related techniques are commonly referred to simply as MIMO. The 5G and NR standards are currently evolving with enhanced MIMO support. A core component of this support in LTE is the support of MIMO antenna deployments and MIMO related techniques. 
     MIMO codebooks for 4-port uplink (UL) transmission supporting variable coherence for NR do not yet exist, and so UEs supporting 4 layer transmission, but only partial or non-coherent operation would not be supported. Also, Rel-10 signaling of a feature group indication for relative transmit phase continuity is insufficient to identify UE capability for UL MIMO operation with fully coherent, partially coherent, and non-coherent operation. 
     SUMMARY 
     An uplink MIMO codebook for 4 antenna ports is constructed using precoding matrices that support fully coherent, partially coherent, and non-coherent operation. The codebook is constructed such that a fixed set of antenna ports is used for partially coherent transmission across all layers using Transmit Precoder Matrix Indicator (TPMIs) derived from the LTE Rel-10 uplink codebook. Fully coherent TPMIs are derived from either the Rel-10 uplink codebook or the Rel-8 downlink codebook. Precoding matrices supporting non-coherent operation are designed, including where TPMI overhead is optimized for ranks 3 and 4. 
     UEs with analog beamforming and multiple transmit (TX) chains can transmit on all TX chains. UEs that support coherent combining of different analog beams can transmit a MIMO layer on different analog beams. UEs that do not support coherent combining of analog beams can transmit different MIMO layers on different analog beams. 
     UEs capable of greater coherency operation can support TPMIs that are associated with lesser coherency. UE capability identifying which antenna ports support partially coherent operation is provided. 
     TPMI field size may be adjusted according to the coherence of the TPMIs conveyed by the TPMI and/or a subset of ranks to be used in transmission. 
     One aspect of the disclosure comprises methods of transmitting data from a UE to a base station in a wireless communication network. The UE comprises multiple antenna ports. The UE receives an indication from the base station for a non-coherent data transmission. The precoding matrix is selected from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers. The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices, the larger set comprising precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. The UE further transmits data to the base station using the indicated precoding matrix. 
     Another aspect of the disclosure comprises methods implemented by a base station of receiving data from a UE having multiple antenna ports. For a non-coherent data transmission, the base station selects a precoding matrix selected from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers. The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices. The larger set of precoding matrices comprises precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. The base station transmits an indication of the selected precoding matrix to the user equipment and receives data transmitted by the UE using the precoding matrix. 
     Another aspect of the disclosure comprises methods implemented by a base station of receiving data from a UE having multiple antenna ports. For a non-coherent data transmission, the base station transmits a selected precoding matrix for a data transmission, the precoding matrix being selected from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers. The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices. The larger set of precoding matrices comprises precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. The base station receives data transmitted by the UE using the selected precoding matrix. 
     Still another aspect of the disclosure comprises a UE configured for operation in a wireless communication network. The UE comprises an interface circuit for communicating with a base station in the wireless communication network and a processing circuit. The processing circuit is configured to receive an indication of a precoding matrix for a non-coherent data transmission. The precoding matrix selected from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers. The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices. The larger set comprising precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. The non-zero magnitude elements represent weights to be applied to respective antenna ports and the zero magnitude elements represent non-transmitting antenna ports. The processing circuit is further configured to transmit data to the base station using the indicated precoding matrix. 
     Another aspect of the disclosure comprises a base station in a wireless communication network. The base station comprises an interface circuit for communicating with one or more UEs and a processing circuit. The processing circuit is configured to select, for a first data transmission, a precoding matrix from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers. The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices. The larger set of precoding matrices comprises precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. The processing circuit is further configured to transmit an indication of the selected precoding matrix to the user equipment and to receive the first data transmission for the UE, the data being transmitted by the UE using the precoding matrix selected for the first data transmission. 
     Another aspect of the disclosure comprises a base station in a wireless communication network. The base station comprises an interface circuit for communicating with one or more UEs and a processing circuit. The processing circuit is configured to transmit, to the UE, a first indication of a precoding matrix for a first data transmission, the precoding being selected from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers. The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices. The larger set of precoding matrices comprises precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. The processing circuit is further configured to receive data transmitted by the UE using the selected precoding matrix. 
     Still another aspect of the disclosure comprises a method implemented by a communication system including a host computer, a base station and a UE. The host computer receives user data transmitted to the base station from the UE, wherein the UE transmits data to the base station non-coherently using a precoding matrix selected from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers. The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices. The larger set of precoding matrices comprises precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. 
     Still another aspect of the disclosure comprises a communication system including a host computer. The communication system comprises a communication interface configured to receive user data originating from a transmission from a user equipment to a base station in a wireless communication network. The user equipment comprises a radio interface and processing circuitry configured to transmit data non-coherently using a precoding matrix selected from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices. The larger set of precoding matrices comprises precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a wireless communication network according to an embodiment. 
         FIG.  2    illustrates a time frequency grid representing radio resources in an OFDM system. 
         FIG.  3    illustrates an exemplary radio frame. 
         FIG.  4    is a block diagram illustrates spatial multiplexing. 
         FIG.  5    illustrates an exemplary antenna array with four panels and two antenna elements on each panel. 
         FIG.  6    is a graph illustrating two sets of coherent antenna ports. 
         FIG.  7    illustrates an exemplary method of data transmission implemented by a user equipment. 
         FIG.  8    illustrates an exemplary method of data transmission implemented by a user equipment. 
         FIG.  9    illustrates an exemplary method of data transmission implemented by a user equipment. 
         FIG.  10    illustrates an exemplary method of data transmission implemented by a user equipment. 
         FIG.  11    illustrates an exemplary method of indicating a precoder matrix for a data transmission implemented by a user equipment. 
         FIG.  12    illustrates an exemplary method of indicating a coherence capability for a data transmission implemented by a user equipment. 
         FIG.  13    illustrates an exemplary method of data transmission implemented by a base station of receiving data from a UE. 
         FIG.  14    illustrates an exemplary method of data transmission implemented by a base station of receiving data from a UE. 
         FIG.  15    illustrates an exemplary method of data transmission implemented by a base station of receiving data from a UE. 
         FIG.  16    illustrates an exemplary method of data transmission implemented by a user equipment. 
         FIG.  17    illustrates an exemplary method of data transmission implemented by a base station of indicating a precoder for an uplink transmission from a UE to the base station. 
         FIG.  18    illustrates an exemplary method of data transmission implemented by a base station of receiving from a UE, an indication of the UE coherence capability. 
         FIG.  19    illustrates an exemplary user equipment according to an embodiment. 
         FIG.  20    illustrates an exemplary base station according to an embodiment. 
         FIG.  21    illustrates an exemplary wireless terminal configured of transmitting of receiving an uplink transmission with variable coherence capability. 
         FIG.  22    illustrates an exemplary wireless network according to an embodiment. 
         FIG.  23    illustrates an exemplary UE according to an embodiment. 
         FIG.  24    illustrates an exemplary virtualization environment according to an embodiment. 
         FIG.  25    illustrates an exemplary telecommunication network connected via an intermediate network to a host computer according to an embodiment. 
         FIG.  26    illustrates an exemplary host computer communicating via a base station with a user equipment over a partially wireless connection according to an embodiment. 
         FIGS.  27 - 30    illustrate an exemplary methods implemented in a communication system, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the disclosure are described in the context of a wireless communication network based on the 5G or NR standard under development by the Third Generation Partnership Project (3GPP). Those skilled in the art will appreciate however that the methods, techniques and apparatus herein described can be adapted for wireless communication networks based on other standards supporting multi-carrier operation. 
       FIG.  1    illustrates communications between a base station  100  and a UE  200  in a wireless communication network  10 . The base station  100 , sometimes referred to in applicable standards as an Evolved Node B (eNB) or 5G Node B (gNB), provides radio coverage to the user equipment  200  in a cell  20  of the wireless communication network  10 . The user equipment  200  may comprise, for example, a cellular telephone, smart phone, laptop computer, notebook computer, tablet, machine-to-machine (M2M) communication device (also referred to as machine-type communication (MTC) device), or other device with wireless communication capabilities. The base station  100  transmits data to the UE  200  in the DL on the Narrowband Physical Downlink Shared Channel (NPDSCH), the Narrowband Physical Downlink Control Channel (NPDCCH), and the Narrowband Physical Broadcast Channel (NPBCH). The UE  200  transmits data to the base station  100  in the UL on the Narrowband Physical Uplink Shared Channel (NPUSCH). The base station  100  and UE  200  are configured to operate according to the 5G or NR standard. 
     Similar to LTE, NR will use Orthogonal Frequency Division Multiplexing (OFDM) in the downlink from a network node or base station (also known as an Evolved NodeB (eNB) or 5G NodeB (gNB)) to a user equipment (UE). In the uplink (i.e., from the UE to gNB), both OFDM and Discrete Fourier Transform (DFT)-spread OFDM will be supported. 
     The basic NR physical resource for 5G and NR networks can be viewed as a time-frequency grid similar to the one in LTE as illustrated in  FIG.  2   , where each resource element corresponds to one OFDM subcarrier during one OFDM symbol interval. Although a subcarrier spacing of Δf=15 kHz is shown in  FIG.  2   , different subcarrier spacing values are supported in NR. The supported subcarrier spacing values (also referred to as different numerologies) in NR are given by Δf=2 μ ×15 kHz, where p is a non-negative integer. 
     Furthermore, the resource allocation in LTE is typically described in terms of resource blocks (RBs), where a resource block corresponds to one slot (0.5 ms) in the time domain and 12 contiguous subcarriers in the frequency domain. RBs are numbered in the frequency domain, starting with 0 from one end of the system bandwidth. For NR, a RB is also 12 subcarriers in frequency but for further study in time domain. A RB is also referred to as physical RB (PRB) in the rest of sections. 
     In the time domain, downlink and uplink transmissions in NR will be organized into equally-sized subframes similar to LTE as shown in  FIG.  3   , which assumes a sub-carrier spacing of 15 kHz. In NR, subframe length for a reference numerology of 2 μ ×15 kHz is exactly ½{circumflex over ( )}μ ms. 
     Downlink transmissions are dynamically scheduled, i.e., in each subframe the gNB transmits downlink control information (DCI) about which UE  200  data is to be transmitted to and which resource blocks in the current downlink subframe the data is transmitted on. This control signaling is typically transmitted in the first one or two OFDM symbols in each subframe in NR. The control information is carried on Physical Control Channel (PDCCH) and data is carried on Physical Downlink Shared Channel (PDSCH). A UE  200  first detects and decodes PDCCH and if a PDCCH is decoded successfully, it decodes the corresponding PDSCH based on the decoded control information in the PDCCH. Each UE  200  is assigned with a unique C-RNTI (Cell Radio Network temporary Identifier) in the same serving cell. The CRC (cyclic redundancy check) bits of a PDCCH for a UE  200  is scrambled by the UE&#39;s  200  C-RNTI, so a UE  200  recognizes its PDCCH by checking the C-RNTI used to scramble the CRC bits of the PDCCH. 
     Uplink data transmissions are also dynamically scheduled using PDCCH. Similar to downlink, a UE  200  first decodes uplink grants in PDCCH and then transmits data over the Physical Uplink Shared Channel (PUSCH) based on the decoded control information in the uplink grant such as modulation order, coding rate, uplink resource allocation, etc. 
     In LTE, semi-persistent scheduling (SPS) is also supported in both uplink and downlink, in which a sequence of periodic data transmissions is activated or deactivated by a single PDCCH. There is no PDCCH transmitted for data transmissions after activation. In SPS, the PDCCH&#39;s CRC is scrambled by a SPS-C-RNTI, which is configured for a UE  200  if the UE  200  supports SPS. 
     In addition to PUSCH, Physical Uplink Control Channel (PUCCH) is also supported in NR to carry uplink control information (UCI) such as HARQ (Hybrid Automatic Repeat Request) related Acknowledgement (ACK), Negative Acknowledgement (NACK), or Channel State Information (CSI) feedback. 
     Codebook-Based Precoding 
     Multi-antenna techniques can significantly increase the data rates and reliability of a wireless communication system. The performance is particularly improved if both the transmitter and the receiver are equipped with multiple antennas, which results in a MIMO communication channel. Such systems and/or related techniques are commonly referred to as MIMO. 
     The NR standard is currently being specified. A core component in NR is the support of MIMO antenna deployments and MIMO related techniques. It is expected that NR will support uplink MIMO with at least 4 layer spatial multiplexing using at least 4 antenna ports with channel dependent precoding. The spatial multiplexing mode is aimed for high data rates in favorable channel conditions. An illustration of the spatial multiplexing operation is provided in  FIG.  4    for where Cyclic Prefix OFDM (CP-OFDM) is used on the uplink. 
     As seen, the information carrying symbol vectors is multiplied by a N T ×r precoder matrix W, which serves to distribute the transmit energy in a subspace of the N T  (corresponding to N T  antenna ports) dimensional vector space. The precoder matrix is typically selected from a codebook of possible precoder matrices, and is typically indicated by means of a transmit precoder matrix indicator (TPMI), which specifies a unique precoder matrix in the codebook for a given number of symbol streams. The r symbols in s each correspond to a layer and r is referred to as the transmission rank. In this way, spatial multiplexing is achieved since multiple symbols can be transmitted simultaneously over the same time/frequency resource element (TFRE). The number of symbols r is typically adapted to suit the current channel properties. 
     Because CP-OFDM is supported for uplink MIMO in NR as opposed to only DFT-S-OFDM for PUSCH in LTE, NR MIMO codebook designs need not emphasize increase in UE  200  power amplifier peak to average power ratios (PAPR) as a design factor as much as was needed for LTE Rel-10 uplink MIMO. Therefore codebooks with limited PAPR increase and those that have relatively high increase in PAPR can be suitable for NR uplink MIMO. Consequently, suitable codebooks for NR uplink MIMO may include the uplink MIMO codebooks defined in clause 5.3.3A of 3GPP technical specification 36.211, as well as the downlink MIMO codebooks in clauses 6.3.4.2.3 of 3GPP technical specification 36.211 and 7.2.4 of 3GPP technical specification 36.213. 
     The received N R ×1 vector y n  for a certain TFRE on subcarrier n (or alternatively data TFRE number n) is thus modeled by: 
         y   n   =H   n   Ws   n   +e   n   Eq. (1)
 
     where e n  is a noise/interference vector obtained as realizations of a random process. The precoder W can be a wideband precoder, which is constant over frequency, or frequency selective. 
     The precoder matrix W is often chosen to match the characteristics of the N R ×N T  MIMO channel matrix H n , resulting in so-called channel dependent precoding. This is also commonly referred to as closed-loop precoding and essentially strives for focusing the transmit energy into a subspace which is strong in the sense of conveying much of the transmitted energy to the UE  200 . In addition, the precoder matrix may also be selected to strive for orthogonalizing the channel, meaning that after proper linear equalization at the UE  200 , the inter-layer interference is reduced. 
     One example method for a UE  200  to select a precoder matrix W can be to select the W k  that maximizes the Frobenius norm of the hypothesized equivalent channel: 
     
       
         
           
             
               
                 
                   
                     max 
                     k 
                   
                   
                     
                        
                       
                         
                           
                             H 
                             ˆ 
                           
                           n 
                         
                         ⁢ 
                         
                           W 
                           k 
                         
                       
                        
                     
                     F 
                     2 
                   
                 
               
               
                 
                   Eq 
                   . 
                       
                   
                     ( 
                     2 
                     ) 
                   
                 
               
             
           
         
       
     
     where, 
     Ĥ n  is a channel estimate, possibly derived from Sounding Reference Signals (SRS). 
     W k  is a hypothesized precoder matrix with index k. 
     Ĥ n W k  is the hypothesized equivalent channel. 
     In closed-loop precoding for the NR uplink, the TRP transmits, based on channel measurements in the reverse link (uplink), TPMI to the UE  200  that the UE  200  should use on its uplink antennas. The gNB configures the UE  200  to transmit SRS according to the number of UE  200  antennas it would like the UE  200  to use for uplink transmission to enable the channel measurements. A single precoder that is supposed to cover a large bandwidth (wideband precoding) may be signaled. It may also be beneficial to match the frequency variations of the channel and instead feedback a frequency-selective precoding report, e.g., several precoders and/or several TPMIs, one per sub-band. 
     Other information than TPMI is generally used to determine the UL MIMO transmission state, such as SRS resource indicators (SRIs) as well as transmission rank indicator (TRIs). These parameters, as well as the modulation and coding state (MCS), and the uplink resources where PUSCH is to be transmitted, are also determined by channel measurements derived from SRS transmissions from the UE  200 . The transmission rank, and thus the number of spatially multiplexed layers, is reflected in the number of columns of the precoder W. For efficient performance, it is important that a transmission rank that matches the channel properties is selected. 
     Control Signaling 
     LTE control signaling can be carried in a variety of ways, including carrying control information on PDCCH or PUCCH, embedded in the PUSCH, in MAC control elements (MAC CEs′), or in RRC signaling. Each of these mechanisms is customized to carry a particular kind of control information. 
     Control information carried on PDCCH, PUCCH, or embedded in (‘piggy backed on’) PUSCH is physical layer related control information, such as downlink control information (DCI), uplink control information (UCI), as described in 3GPP TS 36.211, 36.212, and 36.213. DCI is generally used to instruct the UE  200  to perform some physical layer function, providing the needed information to perform the function. UCI generally provides the network with needed information, such as Hybrid Automatic Repeat Request (HARQ) Acknowledgement (ACK), scheduling request (SR), channel state information (CSI), including CQI, PMI, RI, and/or CRI. UCI and formation (DCI) can be transmitted on a subframe-by-subframe basis, and so are designed to support rapidly varying parameters, including those that can vary with a fast fading radio channel. Because UCI and DCI can be transmitted in every subframe, UCI or DCI corresponding to a given cell tend to be on the order of tens of bits, in order to limit the amount of control overhead. 
     Control information carried in MAC CEs is carried in MAC headers on the uplink and downlink shared transport channels (UL-SCH and DL-SCH), as described in 3GPP TS 36.321. Since a MAC header does not have a fixed size, control information in MAC CEs can be sent when it is needed, and does not necessarily represent a fixed overhead. Furthermore, MAC CEs can carry larger control payloads efficiently, since they are carried in UL-SCH or DL-SCH transport channels, which benefit from link adaptation, HARQ, and can be turbo coded. MAC CEs are used to perform repetitive tasks that use a fixed set of parameters, such as maintaining timing advance or buffer status reporting, but these tasks generally do not require transmission of a MAC CE on a subframe-by-subframe basis. Consequently, channel state information related to a fast fading radio channel, such as PMI, CQI, RI, and CRI are not carried in MAC CEs in LTE up to Rel-14. 
     Multi-Panel UE  200  Antenna Arrays 
     When building UE  200  antenna arrays, it can be challenging to have antennas with the same angular coverage such that they are generally seen by a receiving TRP at the same power level. This can be particularly challenging at the millimeter wave frequencies supported by NR. Furthermore, it may be difficult to place all the UE  200 &#39;s antennas and TX chains close together in the limited spaces available in small mobile devices. One building practice is to use a modular approach wherein the UE  200  TX chains are split into ‘panels’ with one or more transmit chains per panel, as shown in  FIG.  4   . Such multi-panel UEs are generally modeled as having panels with element patterns that point in different directions, while antenna elements within a panel have element patterns that point in the same directions as discussed in 3GPP technical report 36.802. Because the transmit chains in different panels can be separated in UEs, it may be more difficult to maintain calibration and phase coherence between antenna elements in different panels than to maintain calibration and phase coherence between antenna elements in a panel. There may thus exist a frequency offset, timing misalignment, and/or a phase offset between the panels. Aspects of phase coherence among TX chains of different panels is further discussed below. 
       FIG.  5    shows an example of a 4 panel UE  200  array with 8 total antenna elements. Each panel comprises 2 elements with similar antenna patterns that are driven by independent TX chains. The antenna element patterns have roughly 90 degree beamwidth, such that all directions are covered by the 4 panels together. 
     SRS Transmission in NR 
     Sounding reference signals (SRSs) are used for a variety of purposes in LTE, and are expected to serve similar purposes in NR. One primary use for SRS is for uplink channel state estimation, allowing channel quality estimation to enable uplink link adaptation (including determination of which MCS state the UE  200  should transmit with) and/or frequency-selective scheduling. In the context of uplink MIMO, they can also be used to determine precoders and a number of layers that will provide good uplink throughput and/or SINR when the UE  200  uses them for transmission on its uplink antenna array. Additional uses include power control and uplink timing advance adjustment. 
     Unlike LTE Rel-14, at least some NR UEs may be capable of transmitting multiple SRS resources. This is similar conceptually to multiple CSI-RS resources on the downlink: an SRS resource comprises one or more SRS ports, and the UE  200  may apply a beamformer and/or a precoder to the SRS ports within the SRS resource such that they are transmitted with the same effective antenna pattern. A primary motivation for defining multiple SRS resources in the UE  200  is to support analog beamforming in the UE  200  where a UE  200  can transmit with a variety of beam patterns, but only one at a time. Such analog beamforming may have relatively high directivity, especially at the higher frequencies that can be supported by NR. Earlier LTE uplink MIMO and transmit diversity designs did not focus on cases where high directivity beamforming could be used on different SRS ports, and so a single SRS resource was sufficient. When an NR UE  200  transmits on different beams, the power received by the TRP can be substantially different. One approach could be to have a single SRS resource, but to indicate to the UE  200  which of its beams to use for transmission. However, since UE  200  antenna designs vary widely among UEs and UE  200  antenna patterns can be highly irregular, it is infeasible to have a predetermined set of UE  200  antenna patterns with which the TRP could control UE  200  uplink precoding or beamforming. Therefore, an NR UE  200  may transmit on multiple SRS resources using a distinct effective antenna pattern on each SRS resource, allowing the TRP to determine the composite channel characteristics and quality for the different effective antenna patterns used by the UE  200 . Given this association of each effective antenna pattern with a corresponding SRS resource, the TRP can then indicate to the UE  200  which of one or more effective antenna patterns should be used for transmission on PUSCH (or other physical channels or signals) through one or more SRS resource indicator, or ‘SRIs’. 
     UE Coherence Capability in NR 
     Depending on UE implementation, it may be possible to maintain the relative phase of the transmit chains. In this case, the UE  200  can form an adaptive array by selecting a beam on each transmit chain, and by transmitting the same modulation symbol on the selected beams of both transmit chains using different gain and/or phase between the transmit chains. This transmission of a common modulation symbol or signal on multiple antenna elements with controlled phase can be labeled ‘coherent’ transmission’. The support for coherent uplink MIMO transmission in LTE Rel-10 is indicated via a feature group indication for relative transmit phase continuity for uplink spatial multiplexing, wherein a UE  200  indicates if it can adequately maintain the relative phase of transmit chains over time in order to support coherent transmission. 
     In other UE  200  implementations, the relative phase of the transmit chains may not be well controlled, and coherent transmission may not be used. In such implementations, it may still be possible to transmit on one of the transmit chains at a time, or to transmit different modulation symbols on the transmit chains. In the latter case, the modulation symbols on each transmit chain may form a spatially multiplexed, or ‘MIMO’, layer. This class of transmission may be referred to as ‘non-coherent’ transmission. Such non-coherent transmission schemes may be used by LTE Rel-10 UEs with multiple transmit chains, but that do not support relative transmit phase continuity. 
     In still other UE  200  implementations, the relative phase of a subset of the transmit chains is well controlled, but not over all transmit chains. One possible example is described above with respect to multi-panel operation, where phase is well controlled among transmit chains within a panel, but phase between panels is not well controlled. This class of transmission may be referred to as ‘partially-coherent’. 
     All three of these variants of relative phase control have been agreed for support in NR, and so UE  200  capabilities have been defined for full coherence, partial coherence, and non-coherent transmission. 
     Precoder Structure and Capability for Variable Coherence Capability Codebooks 
     It is possible to support all 3 NR coherence capabilities in one MIMO codebook. A precoding matrix or vector, or ‘precoder’, without any zero magnitude elements requires a fully coherent transmission chain to maintain the relative phase set by the non-zero magnitude elements, and so such a precoder can only be used by a UE  200  with a ‘fully coherent’ capability, and is not supported by UEs with partial coherence or non-coherent capabilities. 
     A precoding matrix or vector, or ‘precoder’, with only one non-zero magnitude element for every spatial layer (for example where a precoding matrix with multiple columns has only one non-zero magnitude in every column) does not require phase coherence, since no antenna ports within a spatial layer are combined together. Therefore, such a precoder can be used by a UE  200  that only supports non-coherent transmission. 
     A precoding matrix or vector, or ‘precoder’, with multiple non-zero magnitude elements and at least one zero magnitude element for a given spatial layer (for example where a precoding matrix with multiple columns has only one zero magnitude per column) requires phase coherence only among the antenna ports corresponding to the non-zero ports when transmitting that spatial layer. Such UEs therefore support partial coherence, but not full coherence capability for at least the given spatial layer. When transmitting multiple spatial layers, if two ports require coherence on one layer, they will require it for all layers, since if a TX chain must maintain well controlled phase with another TX chain for one layer, it must do so for all layers. Then, in an embodiment, a partially coherent precoder is one where if an antenna port is combined with another antenna port on one layer, then it can be combined with the other port on any layer, and each antenna port is only combined with a subset of the other antenna ports across all layers. 
     Which ports are coherently combined across all layers can be determined with an iterative process, starting with what is combined for each layer, and continuing until all coherent combinations across all layers are identified. For example, consider a 6 port rank 4 precoder where port pairs (1,2), (3,4), (5,6), and (1,6) are combined on a first, second, third, and fourth layer, respectively, as would occur using the precoding matrix below, where each column corresponds to a layer and each row to an antenna port. 
     
       
         
           
             
               
                 
                   [ 
                   
                     
                       
                         1 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         1 
                       
                     
                     
                       
                         j 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         1 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         1 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         1 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         
                           - 
                           1 
                         
                       
                       
                         1 
                       
                     
                   
                   ] 
                 
               
               
                 
                   Eq 
                   . 
                       
                   
                     ( 
                     3 
                     ) 
                   
                 
               
             
           
         
       
     
     By constructing a combinatorial graph using these dependencies, as illustrated in  FIG.  6   , it can be determined that there are two sets of ports, {3,4} and {1,2,5,6} for this precoder which means that the ports within each of these sets should be coherently transmitted together. Hence, we conclude that ports (1,2,5,6) should be coherently transmitted together and ports (3,4) should be coherently transmitted together. 
     Since a fully coherent UE  200  is capable of partial coherence and non-coherent transmission, precoders with all, a part, or only one non-zero magnitude element per spatial layer can all be in a codebook used for fully coherent transmission. 
     While all 3 coherence capabilities can be in one codebook, UEs with either partial or non-coherent capability can&#39;t support the entire codebook. However, partial coherence capable UEs can use precoders from the codebook that match the antenna ports on which it can transmit coherently, as well as those that do not require coherence. Similarly, a UE  200  supporting only non-coherent capability can use precoders from the codebook that do not require coherent transmission. Therefore, in an embodiment, a UE  200  indicating full coherence is assumed to support TPMIs identifying precoders where all elements have non-zero magnitude, precoders where at least one element has zero magnitude, and precoders where only one element per spatial layer has non-zero magnitude. A UE  200  indicating partial coherence is assumed to support TPMIs identifying precoders where at least one element has zero magnitude, and precoders where only one element per spatial layer has non-zero magnitude. A UE  200  indicating non-coherent capability is assumed to support TPMIs identifying precoders where only one element per spatial layer has non-zero magnitude. 
     A partially coherent UE  200  can only maintain well controlled relative phase between particular transmit chains and antenna ports. Therefore, not only the number of non-zero magnitude elements a precoder has must match the partial coherence capability, but the elements which have non-zero magnitude on a spatial layer must correspond to antenna ports for which phase is well maintained. Non-zero elements in the precoding matrices represent weights to be applied to respective antenna ports while zero magnitude elements represent non-transmitting antenna ports. In one embodiment, in order to identify its partial coherence capability, a UE  200  can indicate which pairs of antenna ports can support coherent operation. Such an indication may be a list of integer pairs, each integer identifying an antenna port number, where the pair supports coherent transmission. Alternatively, multiple bitmaps could be indicated, where each bitmap contains at most two non-zero bits, corresponding to antenna ports for which coherent transmission is supported. 
     In some implementations, the ability of a UE to maintain well controlled relative phase across TX chains may also be a function of the carrier frequency. Therefore, in an embodiment, a UE  200  may indicate a first and a second value of coherence capability, respectively corresponding to a first and a second frequency band used for transmission by the UE  200 . 
     UEs  200  are generally free to select which transmit antenna chains correspond to its antenna ports. If a single set of antenna ports is assumed to be allowed for partially coherent transmission, then a UE  200  supporting partial coherence can align its transmit chains to match the antenna port coherence assumption used by codebook, and no additional information on which of the UE&#39;s antenna ports support coherent transmission is needed by the network. However, the antenna ports for which coherent transmission is supported must be aligned across different transmission ranks. This means that only the elements of precoders that correspond to those antenna ports for which coherent transmission is supported can have non-zero magnitude on any spatial layer. 
     4-Port Variable Coherence Capability Codebooks Using LTE Rel-10 Uplink Precoders 
     This constraint of non-zero weights across different transmission ranks can be illustrated with a design for a codebook supporting full coherence, partial coherence, and non-coherent codewords. Such a codebook can be constructed from the LTE Rel-10 uplink MIMO codebook from 3GPP TS 36.211, section 5.5.3A. Table 1 (which is Table 5.3.3A.2-2 in 3GPP TS 36.211) provides the codebook for rank 1 (i.e., v=1 spatial layer) transmission. Note that while the codebook is illustrated using antenna ports 40, 41, 42, and 43, any antenna port numbering can be used that identifies 4 distinct antenna ports. Here, codebook indices 0-15 all have non-zero magnitude on all entries, and so require fully coherent transmission. However, codebook indices 16-23 have two non-zero magnitude entries each and so can be supported with partially coherent transmission. Since the first element in the vector corresponds to antenna port 40, the second to port 41, etc., and since the first and third elements of codebook indices 16-19 are non-zero magnitude, these indices require coherent transmission on antenna ports 40 and 42. Similarly, codebook indices 19-23 require coherent transmission on antenna ports 41 and 43. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Codebook for transmission on antenna ports {40, 41, 42, 43} with υ = l 
               
            
           
           
               
               
            
               
                 Code-  
                   
               
               
                 book 
                   
               
               
                 index 
                 Number of layers υ = 1 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 0-7 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                  8-15 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                 16-23 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     Table 2 (which is a Table 5.3.3A.2-3 in 3GPP TS 36.211 for LTE Release 10) provides the codebook for rank 2 (i.e. v=2 spatial layers) transmission. Each matrix in the table has two columns, each of which correspond to one spatial layer. Examining codebook indices 0-7, since the first two elements of the first column and the last two elements of the second column are non-zero, antenna ports 40 and 41 should be transmitted with a controlled relative phase, and antenna ports 42 and 43 should also be transmitted with a controlled relative phase. However, because their corresponding non-zero magnitude elements are on different spatial layers, it is not necessary to control the relative phase between antenna ports 40 and 42 nor between antenna ports 41 and 43. 
     Observing that antenna port pair 40 and 42 must be transmitted coherently in rank 1, while port pair 40 and 41 must be transmitted coherently for the first layer of rank 2, it can be seen that if codewords 16-23 were used for partially coherent transmission, then a UE  200  would have to support coherent transmission across ports 40, 41, and 42. A similar observation can be made for these codewords considering the second layer of rank 2: port pairs 41 and 43 should support coherent transmission for rank 1, while port pairs 42 and 43 should support coherent transmission for rank 2, and so ports 41, 42, and 43 should support coherent transmission. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Codebook for transmission on antenna ports {40, 41, 42, 43) with υ = 2 
               
            
           
           
               
               
            
               
                 Code- 
                   
               
               
                 book 
                   
               
               
                 index 
                 Number of layers υ = 2 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                 4-7 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                  8-11 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                 12-15 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     It may be desirable to require only two pairs of coherent ports in partially coherent transmission over 4 ports, rather than requiring coherent transmission across ports 40-42 and 41-43. One way to achieve this is to allow usage of antenna port pairs (40,42) and (41,43) for coherent transmission in rank 2. Since reordering antenna ports for all codebook indices for a given rank of a codebook does not affect the mutual distance or radio link performance of those codewords, reordering either the rank 1 or rank 2 codebook can be a tool to align ports pairs across ranks. 
     In order to determine the port reordering, it is desirable to find a reordering that allows as many partially coherent codewords to be used across ranks as possible. Although codebook indices 8-15 always have at most two non-zero magnitude elements per layer, these correspond to a mixture of antenna port pairs. Indices 8-11 correspond to port pairs 40 and 42 for the first layer, and 41 and 43 for the second layer, while indices 12-15 correspond to port pairs (40,43) and (41,42) for the two layers, respectively. This means that port pairs (41,42) and (42,43) have a more consistent usage of the same antenna ports, since they are used over 8 indices, while the other port pairs are used over only 4 indices. Consequently indices 0-7 seem the best candidates to align to rank 1 through a reordering of antenna ports. 
     If rows 2 and 3, or equivalently antenna ports 41 and 42 are swapped, then the codebook in Table 2 becomes Table 3 below. The codebook indices 0-7 in Table 4 have zeros in the same columns as those in codebook indices 16-23 of Table 1, and so the same antenna port pairs (40,42) and (41,43) require coherent transmission for both ranks 1 and 2. Therefore, reordering the ports allows 8 codewords from rank 1 and 2 to be used for partially coherent transmission with only two port pairs, as opposed to two port triplets (40,41,42) and (41,42,43) without the port reordering. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Modified Codebook for transmission on 
               
               
                 antenna ports {40, 41, 42, 43) with υ = 2 
               
            
           
           
               
               
            
               
                 Code- 
                   
               
               
                 book  
                   
               
               
                 index 
                 Number of layers υ = 2 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                 4-7 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                  8-11 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                 12-15 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     Therefore, in an embodiment, a partial coherence capability uses a first set of precoding matrices for one spatial layer, wherein each precoding matrix in the set has a first column with at least two non-zero magnitude elements that correspond to at least a first and a second antenna port, at least one zero magnitude element in and the first column that corresponds to at least a third antenna port. The partial coherence capability uses a second set of precoding matrices for two spatial layers, wherein each precoding matrix in the second set has a second column with at least two non-zero magnitude elements that correspond to the at least first and second antenna ports, and at least one zero magnitude element in the second column that corresponds to at least the third antenna port. Herein, a matrix can comprise one or more columns. 
     Using partial coherence for rank 3 on the same set of antenna ports may be desirable. The Rel-10 LTE uplink MIMO codebook for rank 3 (Table 5.3.3A.2-4 in 3GPP TS 36.211) is shown in Table 4 below. While 2 of the 3 columns in all of the codebook indices have only one non-zero magnitude element, the first column has two non-zero magnitude elements. This first column therefore requires partially coherent transmission on one port pair for the first spatial layer. Codebook indices 2 and 3 have non-zero magnitude on rows 1 and 3, and so correspond to port pair (40,42). Similarly, codebook indices 8 and 9 have non-zero magnitude on rows 2 and 4, and so correspond to port pair (40,42). Therefore, codebook indices 2, 3, 8, and 9 can be used for partially coherent transmission with rank 2 codebook indices 0-7 of Table 3 and rank 1 codebook indices 16-23 of Table 1. The remaining codebook indices from Table 4 require coherent transmission on other port pairs than (40,42) and (41,43). 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Codebook for transmission on antenna ports {40, 41, 42, 43} with υ = 3 
               
            
           
           
               
               
            
               
                 Code- 
                   
               
               
                 book 
                   
               
               
                 index 
                 Number of layers υ = 3 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                 4-7 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
               
                  8-11 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     To support fully non-coherent operation, it is necessary to add precoding matrices to the Rel-10 UL MIMO 4 port codebooks, since no columns in the precoding matrices of these codebooks has a single non-zero magnitude element. For rank 1 operation, it may be desirable to select any one antenna port, since it may be assumed that any port is equally likely to have the best SINR at the receiver. As such, the following 4 precoders in Table 5 can be added to the rank 1 codebook of Table 2 to support non-coherent operation. 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Additional codebook entries for transmission on antenna ports  
               
               
                 {40, 41, 42, 43} with υ = l enabling non-coherent operation 
               
            
           
           
               
               
            
               
                 Codebook index 
                 Number of layers υ = l 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     Note that in Table 5, a scaling factor of ½ is used, although the precoders only contain one non-zero unit magnitude element, resulting in that the precoders are normalized to ¼ power rather than having a unit norm. Alternatively, another scaling factor may be applied, such as a scaling factor of 1, to normalize the precoders to unit norm, this alternative is illustrated in Table 6 below. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Additional codebook entries for transmission on antenna ports  
               
               
                 {40, 41, 42, 43} with υ = l enabling non-coherent operation,  
               
               
                 using unit norm scaling factor 
               
            
           
           
               
               
            
               
                 Codebook index 
                 Number of layers υ = l 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     For rank 2 operation, it may be desirable to select any antenna port pair across the two layers, since any combination of two ports could have the best SINR at the receiver. As such, the following 6 precoders in Table 7 can be added to the rank 2 codebook of Table 4 to support non-coherent operation. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Additional codebook entries for transmission on antenna ports  
               
               
                 {40, 41, 42, 43} with υ = 2 enabling non-coherent operation 
               
            
           
           
               
               
            
               
                 Codebook index 
                 Number of layers υ = 2 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     Similarly as for the rank 1 codebook, an alternative scaling factor may be applied instead of the scaling factor ½ power used in the above, for instance to normalize the precoders to unit norm. In Table 8, a scaling factor of 
     
       
         
           
             1 
             
               2 
             
           
         
       
     
     is applied so that the precoders are normalized to unit norm. This is illustrated in Table 8 below. Generally, the embodiments herein may utilize an arbitrary scaling factor. 
     
       
         
           
               
             
               
                 TABLE 8 
               
             
            
               
                   
               
               
                 Additional codebook entries for transmission on antenna ports {40, 41, 42, 43} 
               
               
                 with υ = 2 enabling non-coherent operation, using unit norm scaling factor 
               
            
           
           
               
               
            
               
                 Codebook 
                   
               
               
                 index 
                 Number of layers υ = 2 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     For rank 3 operation, it may again be desirable to select any combination of 3 antenna ports pair across the two layers, since any combination of three ports could have the best SINR at the receiver. As such, the following 4 precoders in Table 9 can be added to the rank 3 codebook of Table 4 to support non-coherent operation. 
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 Additional codebook entries for transmission on antenna ports 
               
               
                 {40, 41, 42, 43} with υ = 3 enabling non-coherent operation 
               
            
           
           
               
               
               
            
               
                 Codebook  
                   
                   
               
            
           
           
               
               
            
               
                 index 
                 Number of layers υ = 3 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     For rank 4 operation, an identity matrix can provide good performance. As is known in the art, if the number of transmit antenna ports is equal to the number of layers, no extra degrees of freedom are available to provide array gain. Therefore, a suitable codebook for rank 4 operation with 4 ports can be the Rel-10 UL MIMO 4 port codebook (Table 5.3.3A.2-5 in 3GPP TS 36.211) that is in Table 10 below. 
     
       
         
           
               
             
               
                 TABLE 10 
               
             
            
               
                   
               
               
                 Codebook for transmission on antenna ports  
               
               
                 {40, 41, 42, 43} with υ = 4  
               
            
           
           
               
               
               
            
               
                   
                 Codebook index 
                 Number of layers υ = 4 
               
               
                   
                   
               
               
                   
                 0 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
                   
               
            
           
         
       
     
     Since Table 10 has only one non-zero magnitude element per column, it can be used with non-coherent operation. 
     Given the above analyses, it is possible to construct a codebook that supports full coherent, partial coherent, and non-coherent operation. The codebook can be considered to comprise all matrices needed for all ranks supported in the codebook. In this case, the codebook comprises the following Tables 11-14. Each of the tables comprises matrices associated with a codebook index, or equivalently a TPMI. The codebooks are arranged such that TPMIs are classified according to the minimum coherence capability needed to support the TPMIs, where a coherence capability of fully coherent operation is considered to have the greatest capability, partially coherent operation is the next greatest coherence capability, and non-coherent operation is the least of the coherence capabilities. A UE  200  capable of fully coherent operation can support TPMIs associated with fully coherent, partially coherent, and non-coherent operation. A UE  200  capable of partially coherent operation can support TPMIs associated with partially coherent, and non-coherent operation, but not fully coherent operation. A UE  200  capable of only non-coherent operation can only support TPMIs associated with non-coherent operation. The minimum coherence capability associated with TPMIs on one or more rows is shown in the rightmost column. 
     The partial coherence TPMIs used for ranks 2 and 3 are designed such that antenna ports (40,42) and (41,43) require coherent transmission for all partially coherent TPMIs in the codebook for ranks 1, 2, and 3. This excludes TPMIs that could support partially coherent transmission on other antenna ports, such as TPMIs 8-15 for rank 2 and TPMIs 4-11 in rank 3. Since these TPMIs can provide additional performance, but require coherent transmission across other port pairs than (40,42) and (41,43), these TPMIs are used with the fully coherent minimum coherence capability. Therefore, in an embodiment, a full coherence capability uses a first set of precoding matrices for two spatial layers, wherein each precoding matrix in the first set has at least two non-zero magnitude elements that correspond to the at least a first and a second antenna port, at least one zero magnitude element that corresponds to at least a third antenna port, and the full coherence capability uses a second set of precoding matrices for one spatial layer, wherein each precoding matrix in the second set has non-zero magnitude elements that correspond to at least the first, second, and third antenna ports. 
     
       
         
           
               
             
               
                 TABLE 11 
               
             
            
               
                   
               
               
                 Variable coherence codebook for transmission on 
               
               
                 antenna ports {40, 41, 42, 43} with υ = 1  
               
            
           
           
               
               
               
            
               
                   
                   
                 Minimum 
               
               
                 Codebook 
                   
                 Coherence 
               
               
                 index 
                 Number of layers υ = l 
                 Capability 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 0-7 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Fully Coherent 
               
               
                   
               
               
                  8-15 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                   
               
               
                   
               
               
                 16-23 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Partially Coherent 
               
               
                   
               
               
                 24-27 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                   
                   
                   
                   
                 Non- Coherent 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 12 
               
             
            
               
                   
               
               
                 Variable coherence codebook for transmission on 
               
               
                 antenna ports {40, 41, 42, 43} with υ = 2 
               
            
           
           
               
               
               
            
               
                   
                   
                 Mini- 
               
               
                   
                   
                 mum 
               
               
                   
                   
                 Coher- 
               
               
                 Code-  
                   
                 ence 
               
               
                 book 
                   
                 Capa- 
               
               
                 index 
                 Number of layers υ = 2 
                 bility 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Partially Coherent 
               
               
                   
               
               
                 4-7 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                   
               
               
                   
               
               
                  8-11 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                               
                           
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Fully Coherent 
               
               
                   
               
               
                 12-15 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                   
               
               
                   
               
               
                 16-19 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Non- Coherent 
               
               
                   
               
               
                 20-21 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 13 
               
             
            
               
                   
               
               
                 Variable coherence codebook for transmission on 
               
               
                 antenna ports {40, 41, 42, 43} with υ = 3 
               
            
           
           
               
               
               
            
               
                   
                   
                 Mini- 
               
               
                   
                   
                 mum 
               
               
                   
                   
                 Co- 
               
               
                   
                   
                 her- 
               
               
                   
                   
                 ence 
               
               
                 Code- 
                   
                 Capa- 
               
               
                 book 
                   
                 bil- 
               
               
                 index 
                 Number of layers υ = 3 
                 ity 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Par- tially Co- her- ent 
               
               
                   
               
               
                 4-7 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Fully Co- her- ent 
               
               
                   
               
               
                  8-11 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                   
               
               
                   
               
               
                 12-15 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Non- Co- her- ent 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 14 
               
             
            
               
                   
               
               
                 Variable coherence codebook for transmission on 
               
               
                 antenna ports {40, 41, 42, 43} with υ = 4 
               
            
           
           
               
               
               
               
            
               
                   
                   
                   
                 Minimum 
               
               
                   
                 Codebook 
                   
                 Coherence 
               
               
                   
                 index 
                 Number of layers υ = 4 
                 Capability 
               
               
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 0 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Non- Coherent 
               
               
                   
                   
               
            
           
         
       
     
     In order to construct the signaling for TPMI, it is necessary to determine the number of states. Table 15 below is an alternative representation of the 4 port codebook of Tables 11-14 that indicates the number of TPMIs used per rank and per coherence capability. 
     
       
         
           
               
             
               
                 TABLE 15 
               
             
            
               
                   
               
               
                 TPMIs and number of states vs. minimum coherence 
               
               
                 capability for 4 port codebook 
               
            
           
           
               
               
               
               
            
               
                   
                 Full Coherence 
                 Partial Coherent 
                 Non Coherent 
               
               
                 Rank 
                 Min. Capability 
                 Min. Capability 
                 Min. Capability 
               
               
                   
               
               
                 1 
                 Table 11 TPMIs 
                 Table 11 TPMIs 
                 Table 11 TPMIs 
               
               
                   
                 0-15 (16 TPMIs) 
                 16-23 (8 TPMIs) 
                 24-27 (4 TPMIs) 
               
               
                 2 
                 Table 12 TPMIs 
                 Table 12 TPMIs 
                 Table 12 TPMIs 
               
               
                   
                 8-15 (8 TPMIs) 
                 0-7 (8 TPMIs) 
                 16-21 (6 TPMIs) 
               
               
                 3 
                 Table 13 TPMIs 
                 Table 13 TPMIs 
                 Table 13 TPMIs 
               
               
                   
                 4-11 (8 TPMIs) 
                 0-3 (4 TPMIs) 
                 12-15 (4 TPMIs) 
               
               
                 4 
                 0 
                 0 
                 Table 14 TPMI 
               
               
                   
                   
                   
                 0 (1 TPMI) 
               
               
                   
               
            
           
         
       
     
     Table 16 below is another representation of the 4 port codebook of Tables 11-14 that indicates the total number of TPMIs supported by a UE  200  with a given coherence capability per rank. Here, the TPMIs for partial coherent and non-coherent operation are included in the total for full coherence capable UEs, since such UEs can also transmit partially coherent and non-coherent TPMIs. Similarly, the TPMIs for non-coherent operation are included in the total for partial coherent partially coherent capable UEs, since such UEs can also support non-coherent TPMIs. Finally, non-coherent TPMIs are only in the total TPMIs, since UEs supporting only non-coherent capable can only support these TPMIs. It can be observed that Table 16 can be referred to as comprising 3 codebooks: one for fully coherent operation, one for partially coherent operation, and another for non-coherent operation. Therefore, in some embodiments, a UE  200  is configured with an uplink MIMO codebook identified as supporting full coherence, partial coherence, or non-coherent operation. In such embodiments, TPMIs identified with non-coherent operation or partially coherent operation may be included in a codebook configured to a UE  200  for fully coherent operation, and TPMIs identified with non-coherent operation may be included in a codebook configured to a UE  200  for partially coherent operation. 
     
       
         
           
               
             
               
                 TABLE 16 
               
             
            
               
                   
               
               
                 Total TPMIs and number of states vs. minimum 
               
               
                 coherence capability for 4 port codebook 
               
            
           
           
               
               
               
               
            
               
                   
                 Total Full 
                 Total Partial 
                 Total Non 
               
               
                 Rank 
                 Coherence TPMIs 
                 Coherent TPMIs 
                 Coherent TPMIs 
               
               
                   
               
               
                 1 
                 Table 11 TPMIs 
                 Table 11 TPMIs 
                 Table 11 TPMIs 
               
               
                   
                 0-27 (28 TPMIs) 
                 16-27 (12 TPMIs) 
                 24-27 (4 TPMIs) 
               
               
                 2 
                 Table 12 TPMIs 
                 Table 12 TPMIs 
                 Table 12 TPMIs 
               
               
                   
                 0-21 (22 TPMIs) 
                 0-7, 16-21 (14 TPMIs) 
                 16-21 (6 TPMIs) 
               
               
                 3 
                 Table 13 TPMIs 
                 Table 13 TPMIs 
                 Table 13 TPMIs 
               
               
                   
                 0-15 (16 TPMIs) 
                 0-3, 12-15 (8 TPMIs) 
                 12-15 (4 TPMIs) 
               
               
                 4 
                 Table 14 TPMI 
                 Table 14 TPMI 
                 Table 14 TPMI 
               
               
                   
                 0 (1 TPMI) 
                 0 (1 TPMI) 
                 0 (1 TPMI) 
               
               
                   
               
            
           
         
       
     
     Table 17 shows the number of TPMIs per coherence capability, accumulated per rank from Table 16. This accumulation of rank allows TRI information to be jointly encoded with TPMI, and so in this embodiment, a TPMI indication can also be labeled as TPMI/TRI, and a given value of the TPMI indication conveys the number of spatial layers to be used in the transmission. The number of bits needed to signal the number of TPMIs is also shown. For a given row of Table 17, the number of TPMIs from the row above (if any) are added to determine the number of TPMIs for the rank corresponding to the row and the prior ranks. 
     Examining Table 17, we see that the number of states varies according to the coherence capability and the maximum rank. In this design, the number of states tends to decrease according to coherence capability such that at least one bit less is needed for each lower capability than the one above. Therefore, in an embodiment, a UE  200  receives a TPMI field in a control channel wherein a first TPMI field configuration can identify TPMIs associated with a first and a second coherence capability, a second TPMI field configuration can identify TPMIs associated with the second coherence capability, but not the first coherence capability. Some embodiments may use one information bit field in the control channel to convey both a selected precoding matrix and a number of layers to be used in transmission. In some embodiments, the second TPMI field configuration occupies fewer information bits in the control channel than the first TPMI field configuration. 
     It can also be observed from Table 17 that the number of bits needed to convey PMI and/or rank decreases with the maximum rank. Therefore, in some embodiments, the number of information bits in a control channel used to identify precoding matrices associated with a coherence capability is set to be equal to ┌log 2  N┐, when N comprises the number of precoding matrices associated with the coherence capability in a subset of ranks to be used in transmission, and ┌x┐ is the least integer greater than or equal to x. The subset may be indicated by a bitmap whose length is equal to the number of ports supported by a codebook containing the precoding matrices, wherein each bit indicates if precoding matrices for the corresponding spatial layer can be indicated by the TPMI field. Alternatively, the subset may be indicated by a maximum rank value, such that ranks from 1 to the maximum rank value can be indicated by the TPMI field. 
     
       
         
           
               
             
               
                 TABLE 17 
               
             
            
               
                   
               
               
                 Number of TPMIs vs. minimum coherence 
               
               
                 capability for 4 port codebook 
               
            
           
           
               
               
               
               
            
               
                   
                 Full Coherence 
                 Partial Coherent 
                 Non Coherent 
               
               
                   
                 Capability 
                 Capability 
                 Capability 
               
               
                 Cumulative 
                 Cumulative 
                 Cumulative 
                 Cumulative 
               
               
                 Rank 
                 Sum of TPMIs 
                 Sum of TPMIs 
                 Sum of TPMIs 
               
               
                   
               
               
                 Rank 1 
                 28 (5 bits) 
                 12 (4 bits) 
                  4 (2 bits) 
               
               
                 Rank 1-2 
                 50 (6 bits) 
                 26 (5 bits) 
                 10 (4 bits) 
               
               
                 Rank 1-3 
                 66 (6 bits) 
                 34 (6 bits) 
                 14 (4 bits) 
               
               
                 Rank 1-4 
                 67 (7 bits) 
                 35 (6 bits) 
                 15 (4 bits) 
               
               
                   
               
            
           
         
       
     
     We note that the full and partial coherence capabilities have slightly more TPMIs than can be signaled with one less bit. Therefore, in an alternative embodiment shown in Table 18, we eliminate 3 of the TPMIs for rank 3, as shown below. The 3 rank 2 TPMIs that are eliminated should provide limited SNR gain, since antenna selection provided by the extra TPMIs should not improve performance substantially since partially and fully coherent TPMIs are already available, and since rank 3 is near the maximum rank supported by 4 antenna ports. 
     
       
         
           
               
             
               
                 TABLE 18 
               
             
            
               
                   
               
               
                 TPMIs and number of states vs. minimum coherence capability 
               
               
                 for 4 port codebook with reduced overhead 
               
            
           
           
               
               
               
               
            
               
                   
                 Full Coherence 
                 Partial Coherent 
                 Non Coherent 
               
               
                 Rank 
                 Min. Capability 
                 Min. Capability 
                 Min. Capability 
               
               
                   
               
               
                 1 
                 Table 11 TPMIs 
                 Table 11 TPMIs 
                 Table 11 TPMIs 
               
               
                   
                 0-15 (16 TPMIs) 
                 16-23 (8 TPMIs) 
                 24-27 (4 TPMIs) 
               
               
                 2 
                 Table 12 TPMIs 
                 Table 12 TPMIs 
                 Table 12 TPMIs 
               
               
                   
                 8-15 (8 TPMIs) 
                 0-7 (8 TPMIs) 
                 16-21 (6 TPMIs) 
               
               
                 3 
                 Table 13 TPMIs 
                 Table 13 TPMIs 
                 Table 13 TPMI 
               
               
                   
                 4-11 (8 TPMIs) 
                 0-3 (4 TPMIs) 
                 12 (1 TPMI) 
               
               
                 4 
                 0 
                 0 
                 Table 14 TPMI 
               
               
                   
                   
                   
                 0 (1 TPMI) 
               
               
                   
               
            
           
         
       
     
     Examining Table 19, we see that the maximum number of bits needed is 6 rather than 7, and that the lesser coherence capabilities always require fewer TPMI bits. Therefore, in an embodiment, a 4 port codebook that can be used by UEs capable of one or more of fully coherent, partially coherent, and non-coherent transmission has one precoding matrix for rank 3 where all columns of the matrix have no more than one non-zero magnitude element, and one precoding matrix for rank 4 where all columns of the matrix have no more than one non-zero magnitude element. Such an embodiment may further comprise four rank 1 precoding matrices wherein each rank 1 precoding matrix has a single column comprising a single non-zero element, and a set of 6 rank 2 precoding matrices wherein each rank 2 precoding matrix in the set comprises two columns and non-zero magnitude elements, and where matrix in the set of rank 2 precoding matrices is different from every other matrix in the set such that the location of the non-zero magnitude element is different. 
     
       
         
           
               
             
               
                 TABLE 19 
               
             
            
               
                   
               
               
                 Number of TPMIs vs. minimum coherence capability 
               
               
                 for 4 port codebook with reduced overhead 
               
            
           
           
               
               
               
               
            
               
                   
                 Full Coherence 
                 Partial Coherent 
                 Non Coherent 
               
               
                   
                 Capability 
                 Capability 
                 Capability 
               
               
                 Cumulative 
                 Cumulative 
                 Cumulative 
                 Cumulative 
               
               
                 Rank 
                 Sum of TPMIs 
                 Sum of TPMIs 
                 Sum of TPMIs 
               
               
                   
               
               
                 Rank 1 
                 28 (5 bits) 
                 12 (4 bits) 
                  4 (2 bits) 
               
               
                 Rank 1-2 
                 50 (6 bits) 
                 26 (5 bits) 
                 10 (4 bits) 
               
               
                 Rank 1-3 
                 63 (6 bits) 
                 31 (5 bits) 
                 11 (4 bits) 
               
               
                 Rank 1-4 
                 64 (6 bits) 
                 32 (5 bits) 
                 12 (4 bits) 
               
               
                   
               
            
           
         
       
     
     For simplicity, corresponding Table 19A, below, clarifies the size of the field for signaling TPMIs when using a 4 port codebook. 
     
       
         
           
               
             
               
                 TABLE 19a 
               
             
            
               
                   
               
               
                 Size of TPMI field vs. minimum coherence capability 
               
               
                 for 4 port codebook with reduced overhead 
               
            
           
           
               
               
               
               
            
               
                 Cumulative 
                 Full Coherence 
                 Partial Coherent 
                 Non Coherent 
               
               
                 Rank 
                 Capability 
                 Capability 
                 Capability 
               
               
                   
               
               
                 Rank 1 
                 5 bits 
                 4 bits 
                 2 bits 
               
               
                 Rank 1-2 
                 6 bits 
                 5 bits 
                 4 bits 
               
               
                 Rank 1-3 
                 6 bits 
                 5 bits 
                 4 bits 
               
               
                 Rank 1-4 
                 6 bits 
                 5 bits 
                 4 bits 
               
               
                   
               
            
           
         
       
     
     4-Port Variable Coherence Capability Codebooks Using LTE Rel-8 Downlink Precoders 
     When CP-OFDM is used for uplink MIMO transmission, the peak to average power ratio (PAPR) or cubic metric (CM) of the PUSCH transmission may not be a primary design concern, and codebooks that do not minimize PAPR or CM may be suitable. Furthermore, it may be advantageous to use existing codebook designs in order to minimize design effort, and since such existing codebooks may have been proven in their use in deployments. UE  200  antenna systems tend to have more decorrelated antenna ports than in base station  100   s  due to irregular antenna patterns in the UE  200  and due to higher angle spreads found near UEs than near base station  100   s . Since the LTE Rel-8 downlink 4 port codebook was designed with uncorrelated antenna systems in mind, it is a logical candidate to use in an uplink MIMO design for CP-OFDM. Such a codebook does not support partially coherent or non-coherent transmission, however. Therefore, additional precoding matrices should be supported along with Rel-8 precoding matrices. 
     The Rel-8 downlink codebook is constructed with Table 20 below (which is 6.3.4.2.3-2 in 3GPP TS 36.211), where the quantity W n   {s}  for denotes the precoding matrix codebook index n defined by the columns given by the set {s} from the expression W n =I−2u n u n   H /u n   H u n  where I is the 4×4 identity matrix and the vector u n  is given by Table 20. It can be seen that 16 TPMIs are used for each of ranks 1 to 4. This would require 64 states for the fully coherent portion of a codebook, as compared to 32 with the design in Table 18, which would substantially increase the codebook size and require extra TPMI overhead. Therefore, it may be desirable to use a subset of the Rel-8 codebook for some of the ranks. 
     
       
         
           
               
             
               
                 TABLE 20 
               
             
            
               
                   
               
               
                 Codebook for transmission on antenna ports {0, 1, 2, 3}  and 
               
               
                 for CSI reporting based on antenna ports  {0, 1, 2, 3}  or  {15, 16, 17, 18}   
               
            
           
           
               
               
               
            
               
                 Codebook 
                   
                 Number of layers ν 
               
            
           
           
               
               
               
               
               
               
            
               
                 index 
                 u n   
                 1 
                 2 
                 3 
                 4 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 0 
                 u 0  = [1 −1 −1 −1] T   
                 W 0   {1}   
                 W 0   {14} /√{square root over (2)} 
                 W 0   {124} /√{square root over (3)} 
                 W 0   {1234} /2 
               
               
                 1 
                 u 1  = [1 −j 1 j] T   
                 W 1   {1}   
                 W 1   {12} /√{square root over (2)} 
                 W 1   {123} /√{square root over (3)} 
                 W 1   {1234} /2 
               
               
                 2 
                 u 2  = [1 1 −1 1] T   
                 W 2   {1}   
                 W 2   {12} /√{square root over (2)} 
                 W 2   {123} /√{square root over (3)} 
                 W 2   {3214} /2 
               
               
                 3 
                 u 3  = [1 j 1 −j] T   
                 W 3   {1}   
                 W 3   {12} /√{square root over (2)} 
                 W 3   {123} /√{square root over (3)} 
                 W 3   {3214} /2 
               
               
                 4 
                 u 4  = [1 (−1 − j)/√{square root over (2)} −j (1 − j)/√{square root over (2)}] T   
                 W 4   {1}   
                 W 4   {14} /√{square root over (2)} 
                 W 4   {124} /√{square root over (3)} 
                 W 4   {1234} /2 
               
               
                 5 
                 u 5  = [1 (1 − j)/√{square root over (2)} j (−1 − j)/√{square root over (2)}] T   
                 W 5   {1}   
                 W 5   {14} /√{square root over (2)} 
                 W 5   {124} /√{square root over (3)} 
                 W 5   {1234} /2 
               
               
                 6 
                 u 6  = [1 (1 + j)/√{square root over (2)} −j (−1 + j/√{square root over (2)}] T   
                 W 6   {1}   
                 W 6   {13} /√{square root over (2)} 
                 W 6   {134} /√{square root over (3)} 
                 W 6   {1324} /2 
               
               
                 7 
                 u 7  = [1 (−1 + j)/√{square root over (2)} j (1 + j/√{square root over (2)}] T   
                 W 7   {1}   
                 W 7   {13} /√{square root over (2)} 
                 W 7   {134} /√{square root over (3)} 
                 W 7   {1324} /2 
               
               
                 8 
                 u 8  = [1 −1 1 1] T   
                 W 8   {1}   
                 W 8   {12} /√{square root over (2)} 
                 W 8   {124} /√{square root over (3)} 
                 W 8   {1234} /2 
               
               
                 9 
                 u 9  = [1 −j −1 −j] T   
                 W 9   {1}   
                 W 9   {14} /√{square root over (2)} 
                 W 9   {134} /√{square root over (3)} 
                 W 9   {1234} /2 
               
               
                 10 
                 u 10  = [1 1 1 −1] T   
                 W 10   {1}   
                 W 10   {13} /√{square root over (2)} 
                 W 10   {123} /√{square root over (3)} 
                 W 10   {1324} /2 
               
               
                 11 
                 u 11  = [1 j −1 j] T   
                 W 11   {1}   
                 W 11   {13} /√{square root over (2)} 
                 W 11   {134} /√{square root over (3)} 
                 W 11   {1324} /2 
               
               
                 12 
                 u 12  = [1 −1 −1 1] T   
                 W 12   {1}   
                 W 12   {12} /√{square root over (2)} 
                 W 12   {123} /√{square root over (3)} 
                 W 12   {1234} /2 
               
               
                 13 
                 u 13  = [1 −1 1 −1] T   
                 W 13   {1}   
                 W 13   {13} /√{square root over (2)} 
                 W 13   {123} /√{square root over (3)} 
                 W 13   {1324} /2 
               
               
                 14 
                 u 14  = [1 1 −1 −1] T   
                 W 14   {1}   
                 W 14   {13} /√{square root over (2)} 
                 W 14   {123} /√{square root over (3)} 
                 W 14   {3214} /2 
               
               
                 15 
                 u 15  = [1 1 1 1] T   
                 W 15   {1}   
                 W 15   {12} /√{square root over (2)} 
                 W 15   {123} /√{square root over (3)} 
                 W 15   {1234} /2 
               
               
                   
               
            
           
         
       
     
     The greatest performance benefits from precoding tend to come from rank 1 transmission, and so it may be desirable to use all 16 codebook indices from Table 20 in a reduced size codebook based on Table 20, while using a subset of the indices for ranks 2 to 4. Examining the distance properties of the precoding matrices in Table 20, it can be observed that precoding matrices with codebook indices 4-7 tend to have smaller minimum distance to other precoding matrices. Therefore, indices 4-7 may be excluded from the reduced size codebook. The remaining indices have relatively homogeneous distance properties, but one suitable set of 8 matrices is matrices 0-3 and 8-11. These 8 matrices can be suitable for rank 2 and 3 transmissions. Since there is little benefit from precoding using rank 4 transmission on 4 antennas, the diagonal precoder used for non-coherent transmission is sufficient, and one specifically for fully coherent operation is not needed. Therefore, a reduced size 4 port codebook based on the Rel-8 4 port downlink but that includes support for different coherence capabilities can be constructed in Table 21 below. More generally, in an embodiment, a precoding matrix W n  associated with fully coherent operation is constructed using the equation 
         W   n   =I− 2 u   n   u   n   H   /u   n   H   u   n ,  Eq. (4)
 
     where n is a precoding matrix index, and the values of u n  are determined from Table 20. In some embodiments, n can be one of 16 values for rank 1, one of 8 values for ranks 2 and 3, and the diagonal matrix shown below for rank 4. 
     
       
         
           
             
               
                 
                   
                     W 
                     n 
                   
                   = 
                   
                     [ 
                     
                       
                         
                           1 
                         
                         
                           0 
                         
                         
                           0 
                         
                         
                           0 
                         
                       
                       
                         
                           0 
                         
                         
                           1 
                         
                         
                           0 
                         
                         
                           0 
                         
                       
                       
                         
                           0 
                         
                         
                           0 
                         
                         
                           1 
                         
                         
                           0 
                         
                       
                       
                         
                           0 
                         
                         
                           0 
                         
                         
                           0 
                         
                         
                           1 
                         
                       
                     
                     ] 
                   
                 
               
               
                 
                   Eq 
                   . 
                       
                   
                     ( 
                     5 
                     ) 
                   
                 
               
             
           
         
       
     
     In some embodiments, n∈{0,1,2,3,8,9,10,11} for rank 2 and rank 3 precoding matrices. 
     
       
         
           
               
             
               
                 TABLE 21 
               
             
            
               
                   
               
               
                 TPMIs and number of states vs. minimum coherence capability 
               
               
                 for 4 port codebook using Rel-8 TPMIs with low overhead 
               
            
           
           
               
               
               
               
            
               
                   
                 Full Coherence 
                 Partial Coherent 
                 Non Coherent 
               
               
                 rank 
                 Min. Capability 
                 Min. Capability 
                 Min. Capability 
               
               
                   
               
               
                 1 
                 Table 19 TPMIs 
                 Table 10 TPMIs 
                 Table 10 TPMIs 
               
               
                   
                 0-15 (16 TPMIs) 
                 16-23 (8 TPMIs) 
                 24-27 (4 TPMIs) 
               
               
                 2 
                 Table 19 TPMIs 
                 Table 11 TPMIs 
                 Table 11 TPMIs 
               
               
                   
                 0-3, 8-11 (8 TPMIs) 
                 0-7 (8 TPMIs) 
                 16-21 (6 TPMIs) 
               
               
                 3 
                 Table 19 TPMIs 
                 Table 12 TPMIs 
                 Table 12 TPMI 
               
               
                   
                 0-3, 8-11 (8 TPMIs) 
                 0-3 (4 TPMIs) 
                 12 (1 TPMI) 
               
               
                 4 
                 0 
                 0 
                 Table 13 TPMI 
               
               
                   
                   
                   
                 0 (1 TPMI) 
               
               
                   
               
            
           
         
       
     
     4-Port Variable Coherence Capability Codebooks Using NR Rel-15 Downlink Precoders 
     As in the case of the LTE Rel-8 codebook, when CP-OFDM is used for uplink MIMO transmission and the peak to average power ratio (PAPR) or cubic metric (CM) of the PUSCH transmission is not a primary design concern, the NR Rel-15 downlink codebook although it does not minimize PAPR. The NR Rel-15 downlink codebook may be of particular interest, since antenna correlation can be larger when 4 antennas are used in the UE. 
     Uplink codebooks based Rel-15 downlink codebooks need additional codewords to support both coherent and non-coherent operation, but can use the Rel-15 precoders for the fully coherent portion of the NR 4 Tx codebook for CP-OFDM. Since the Rel-15 based design is not fundamentally different than the Rel-8 based design above, it will also need to contain 64 precoders to be competitive. Therefore, a Rel-15 based codebook design herein also comprises 16, 8, and 8, precoding matrices that are usable only for UEs capable of fully coherent across ranks 1, 2, and 3 respectively. The NR Rel-15 Mode 1 codebook is used, given its compatibility with wideband TPMI and good performance with low overhead. Since 32 precoding matrices are needed for rank 1, we reduce the oversampling factor from O=4 to O=2, thereby reducing the number TPMIs to 16. Furthermore, it is necessary to set i 1,3 =0 for rank 2 in order to reduce to 8 TPMIs for ranks 2 and 3. This leads to the codebook in Tables 21A through 21 D below: 
     
       
         
           
               
             
               
                 TABLE 21A 
               
             
            
               
                   
               
               
                 Codebook Based on NR Rel-15 DL (Rank 1) 
               
            
           
           
               
               
               
            
               
                   
                   
                 Minimum 
               
               
                 Codebook 
                   
                 Coherence 
               
               
                 index 
                 Number of layers υ = 1 
                 Capability 
               
               
                   
               
            
           
           
               
               
               
            
               
                  0-15 
                 NR Rel15 DL codebook with CodeBookMode = 1, but with O 1  = 2 
                 Fully Coherent 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 16-23 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               j 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Partially Coherent 
               
               
                   
               
               
                 24-27 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                   
                   
                   
                   
                 Non- Coherent 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 21B 
               
             
            
               
                   
               
               
                 Codebook Based on NR Rel-15 DL (Rank 2) 
               
            
           
           
               
               
               
            
               
                   
                   
                 Minimum 
               
               
                 Codebook 
                   
                 Coherence  
               
               
                 index 
                 Number of layers υ = 2 
                 Capability 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Partially Coherent 
               
               
                   
               
               
                 4-7 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               j 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                   
               
               
                   
               
            
           
           
               
               
               
            
               
                  8-15 
                 NR Rel15 DL codebook with CodeBookMode = 1, but with O 1  = 2 and i 1,3  = 0 
                 Fully 
               
               
                   
                   
                 Coherent 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 16-19 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Non- Coherent 
               
               
                   
               
               
                 20-21 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 21C 
               
             
            
               
                   
               
               
                 Codebook Based on NR Rel-15 DL (Rank 3) 
               
            
           
           
               
               
               
            
               
                 Codebook  
                   
                 Minimum Coher- 
               
               
                 index 
                 Number of layers υ = 3 
                 ence Capability 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 0-3 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Partially Coherent 
               
               
                   
               
            
           
           
               
               
               
            
               
                  4-11 
                 NR Rel15 codebook with CodeBookMode = l-2, with O 1  = 2 
                 Fully 
               
               
                   
                   
                 Coherent 
               
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 12 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                   
                   
                   
                 Non-Coherent 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 21D 
               
             
            
               
                   
               
               
                 Codebook Based on NR Rel-15 DL (Rank 4) 
               
            
           
           
               
               
               
            
               
                   
                   
                 Minimum 
               
               
                 Codebook  
                   
                 Coherence 
               
               
                 index 
                 Number of layers υ = 4 
                 Capability 
               
               
                   
               
            
           
           
               
               
               
            
               
                 0 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 Non-Coherent 
               
               
                   
               
            
           
         
       
     
     Codebook Subset Restriction Per UE Capability 
     In one embodiment, there is a codebook consisting of N codewords and each codeword is connected to one or multiple of the UE  200  coherence capabilities. In one embodiment, the number of bits allowed for signaling TPMI is less than ┌log 2  N┐. In such an embodiment, codebook subset restriction may be utilized such that only a subset of the codewords are used out of the available N codewords. Furthermore, this codebook subset restriction may be carried out in a UE  200  specific way or alternatively depending on UE  200  coherence capability. Hence, for a certain UE  200  there may be a certain subset of the N precoders which is used for codebook based transmission. This subset may be
         implicitly given by the UE  200  capability, or   explicitly defined by the base station  100  (e.g. gNB), or   explicitly defined by the base station  100  (e.g. gNB) but recommended by the UE  200  through some signaling.       

     In some embodiments, a UE  200  indicates the TPMIs it can support in a UL MIMO codebook using a supported bitmap in capability signaling. The bitmap comprises a number of elements equal to the number of precoding matrices in a codebook over all ranks supported by the codebook, and where each bit in the bitmap corresponds to a precoding matrix identified by a TPMI field used for the codebook in downlink control signaling. In some embodiments, the UE  200  receives a codebook restriction bitmap in response to the supported bitmap for the UL MIMO codebook, where the codebook restriction bitmap identifies the TPMIs that the UE  200  may expect in downlink control signaling for the UL MIMO codebook, and has the same size as the supported bitmap. In some embodiments, the number of information bits in downlink control signaling carrying TPMIs is reduced according to the number of restricted TPMIs in the codebook restriction bitmap. 
     In one embodiment where ┌log 2  N┐ is larger than the number of bits allowed for signaling TPMI we define the codebook by adding the rank 1-3 codewords as presented below in Tables 22-24 to the previous presented codebook in Tables 11-14. 
     
       
         
           
               
             
               
                 TABLE 22 
               
             
            
               
                   
               
               
                 Additional codewords for transmission on 
               
               
                 antenna ports {40, 41, 42, 43} with υ = l 
               
            
           
           
               
               
            
               
                 Code- 
                   
               
               
                 book 
                   
               
               
                 index 
                 Number of layers υ = l 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                 28-36 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                             ⁢ 
                             
                               2 
                             
                           
                         
                         [ 
                         
                           
                             
                               
                                 2 
                               
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 1 
                                 + 
                                 j 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                             ⁢ 
                             
                               2 
                             
                           
                         
                         [ 
                         
                           
                             
                               
                                 2 
                               
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 1 
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                             ⁢ 
                             
                               2 
                             
                           
                         
                         [ 
                         
                           
                             
                               
                                 2 
                               
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 
                                   - 
                                   1 
                                 
                                 + 
                                 j 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                             ⁢ 
                             
                               2 
                             
                           
                         
                         [ 
                         
                           
                             
                               
                                 2 
                               
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 
                                   - 
                                   1 
                                 
                                 - 
                                 j 
                               
                             
                           
                           
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                             ⁢ 
                             
                               2 
                             
                           
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 2 
                               
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 1 
                                 + 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                             ⁢ 
                             
                               2 
                             
                           
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 2 
                               
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 1 
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                             ⁢ 
                             
                               2 
                             
                           
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 2 
                               
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 
                                   - 
                                   1 
                                 
                                 + 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                             ⁢ 
                             
                               2 
                             
                           
                         
                         [ 
                         
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 2 
                               
                             
                           
                           
                             
                               0 
                             
                           
                           
                             
                               
                                 
                                   - 
                                   1 
                                 
                                 - 
                                 j 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 23 
               
             
            
               
                   
               
               
                 Additional codewords for transmission on 
               
               
                 antenna ports {40, 41, 42, 43} with υ = 2 
               
            
           
           
               
               
            
               
                 Codebook  
                   
               
               
                 index 
                 Number of layers υ = 2 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 22-25 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 1 
                               
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               
                                 - 
                                 1 
                               
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 24 
               
             
            
               
                   
               
               
                 Additional codewords for transmission on 
               
               
                 antenna ports {40, 41, 42, 43} with υ = 3 
               
            
           
           
               
               
            
               
                 Codebook  
                   
               
               
                 index 
                 Number of layers υ = 3 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 16-19 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               j 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         [ 
                         
                           
                             
                               0 
                             
                             
                               1 
                             
                             
                               0 
                             
                           
                           
                             
                               1 
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                           
                             
                               0 
                             
                             
                               0 
                             
                             
                               1 
                             
                           
                           
                             
                               
                                 - 
                                 j 
                               
                             
                             
                               0 
                             
                             
                               0 
                             
                           
                         
                         ] 
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     Given this extended codebook, a codebook subset restriction for a full coherence capability UE  200  may result in using the same codewords as in the previous embodiment, hence the 64 codewords as given by Table 25 below. A partial coherence UE  200  will, on the other hand, not be able to use the subset of codewords corresponding to the full coherence codewords. It may then restrict these codewords and instead chose to use other codewords as in Table 25 below. Hence, as illustrated in Table 26, different UEs are using different subsets of the codebook and may further, as in the example of the full coherence UE  200  and partial coherence UE  200 , use the same number of bits to signal TPMI. Different UEs may also, as in the example of the non-coherence UE  200  and partial coherence UE  200 , use different number of bits to signal TPMI. 
     
       
         
           
               
             
               
                 TABLE 25 
               
             
            
               
                   
               
               
                 Subsets of codebooks used for different UEs. 
               
            
           
           
               
               
               
               
            
               
                   
                 Full Coherence 
                 Partial Coherent 
                 Non Coherent 
               
               
                   
                 capability used 
                 used codebook 
                 used codebook 
               
               
                 rank 
                 codebook subset 
                 subset 
                 subset 
               
               
                   
               
               
                 1 
                 TPMIs 0-27 
                 TPMIs 15-36 
                 TPMIs 24-27 
               
               
                 2 
                 TPMIs 0-21 
                 TPMIs 0-7, 16-25 
                 TPMIs 16-21 
               
               
                 3 
                 TPMIs 0-12 
                 TPMIs 0-3, 12-19 
                 TPMI 12 
               
               
                 4 
                 TPMI 0 
                 TPMI 0 
                 TPMI 0 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 26 
               
             
            
               
                   
               
               
                 Subset size used for different UEs. 
               
            
           
           
               
               
               
               
            
               
                   
                 Full Coherence 
                 Partial Coherent 
                 Non Coherent 
               
               
                   
                 Capability 
                 Capability 
                 Capability 
               
               
                 Cumulative 
                 Cumulative 
                 Cumulative 
                 Cumulative 
               
               
                 Rank 
                 Sum of TPMIs 
                 Sum of TPMIs 
                 Sum of TPMIs 
               
               
                   
               
               
                 Rank 1 
                 28 (5 bits) 
                 21 (5 bits) 
                  4 (2 bits) 
               
               
                 Rank 1-2 
                 50 (6 bits) 
                 38 (6 bits) 
                 10 (4 bits) 
               
               
                 Rank 1-3 
                 63 (6 bits) 
                 50 (6 bits) 
                 11 (4 bits) 
               
               
                 Rank 1-4 
                 64 (6 bits) 
                 52 (6 bits) 
                 12 (4 bits) 
               
               
                   
               
            
           
         
       
     
       FIGS.  7 - 18    illustrate various methods of transmitting a receiving data using the precoding matrices as herein described. Generally, the base station  100  selects a precoding matrix from a codebook for a data transmission based on measurements of the uplink channel from the UE  200  to the base station  100  and signals the selected precoding matrix to the UE  200  by transmitting an indication (e.g., TPMI) of the selected precoding matrix to the UE  200 . The codebook supports non-coherent, partially coherent and fully coherent data transmission from the UE  200  to the base station  100 . The UE  200  receives the indication (e.g. TPMI) from the base station  100  and performs an uplink data transmission using the indicated precoding matrix. The base station  100  receives the data transmission from the UE  200 . 
       FIG.  7    illustrates an exemplary method  300  for transmitting data from the UE  200  to a base station  100  in a wireless communication network. The method  300  is implemented by a UE  200  having multiple antenna ports connected to an antenna array. Generally, the UE  200  uses a first set of precoding matrices for a single layer data transmission over two or more antenna ports and a second set of precoding matrices for a data transmission over two spatial layers. For a data transmission on one spatial layer, the UE  200  transmits data over two or more of the antenna ports using a precoding matrix selected from the first set of precoding matrices, which is available for a first coherence capability but not the a lower second coherence capability (block  305 ). Each precoding matrix in the first set of precoding matrices consists of two non-zero magnitude elements and at least one zero magnitude element. For a data transmission on two spatial layers, the UE  200  transmits data over two or more of the antenna ports using a precoding matrix selected from the second set of precoding matrices, which is available for the first coherence capability but not for the lower second coherence capability (block  310 ). Each precoding matrix in the second set of precoding matrices comprises a first and a second column corresponding to respective spatial layers wherein each column consists of two non-zero magnitude elements and at least one zero magnitude element. Non-zero elements in the precoding matrices represent weights to be applied to respective antenna ports while zero magnitude elements represent non-transmitting antenna ports (block  315 ). 
     Some embodiments of the method  300  further comprise transmitting data on three spatial layers. For a data transmission on three spatial layers, the UE  200  transmits data over two or more of the antenna ports using a precoding matrix selected from a third set of precoding matrices, which third set is available for the first coherence capability but not for a lower second coherence capability. Each precoding matrix in the third set of precoding matrices comprises a first, a second and a third column corresponding to respective spatial layers, wherein each column consists of two non-zero magnitude elements and at least one zero magnitude element. 
     In some embodiments of the method  300 , the UE  200  transmits data over three or antenna ports. For a data transmission on one spatial layer, the UE  200  transmits data over three or more of the antenna ports using a precoding matrix selected from a fourth set of precoding matrices, which fourth set is available for a higher third coherence capability but not for the first or second coherence capability. Each precoding matrix in the fourth set of precoding matrices consists of three or more non-zero magnitude elements. For a data transmission on two spatial layers, the UE  200  transmits data over three or more of the antenna ports using a precoding matrix selected from a fifth set of precoding matrices, which fifth set is available for the third coherence capability but not for the first or second coherence capability. Each precoding matrix in the fifth set of precoding matrices comprises a first and a second column corresponding to respective spatial layers, wherein each column consists of at least three non-zero magnitude elements. 
     In some embodiments of the method  300 , the first coherence capability corresponds to a partially coherent transmission capability. 
     In some embodiments of the method  300 , the second coherence capability corresponds to a non-coherent transmission capability. 
     In some embodiments of the method  300 , the third coherence capability corresponds to a fully coherent transmission capability. 
     Some embodiments of the method  300  further comprise indicating, by UE  200 , a coherence capability of the UE  200  to the base station  100 . In some embodiments, when the UE  200  indicates a coherence capability, the UE  200  transmits data transmission in accordance with the indicated coherence capability or a lower coherence capability. 
       FIG.  8    illustrates another method  320  for transmitting data from the UE  200  to a base station  100  in a wireless communication network according to another embodiment. The method  320  is implemented by a UE  200  having multiple antenna ports connected to an antenna array. Generally, the UE  200  uses a first set of precoding matrices for a single layer data transmission over two or more antenna ports and a second set of precoding matrices for a data transmission over two spatial layers. For a data transmission on one spatial layer, the UE  200  transmits data on one or more of the antenna ports using a precoding matrix selected from a first set of precoding matrices configured for a first coherence capability (block  325 ). At least one precoding matrix in the first set of precoding matrices comprises two non-zero magnitude elements corresponding to first and second antenna ports and zero magnitude element corresponding all remaining antenna ports. For a data transmission on two spatial layers, the UE  200  transmits data on one or more of the antenna elements using a precoding matrix selected from a second set of precoding matrices configured for the first coherence capability (block  330 ). Each precoding matrix in the second set of precoding matrices comprises, for each spatial layer, two non-zero magnitude elements corresponding to the first and second antenna ports, and zero magnitude element corresponding all remaining antenna ports, or zero magnitude elements corresponding to the first and second antenna ports respectively. 
     Some embodiments of the method  320  further comprise transmitting data on three spatial layers. For a data transmission on three spatial layers, the UE  200  transmits data on one or more of the antenna elements using a precoding matrix selected from a third set of precoding matrices configured for a first coherence capability. Each precoding matrix in the third set of precoding matrices comprises, for each spatial layer, two non-zero magnitude elements corresponding to the first and second antenna ports and zero magnitude elements corresponding to all remaining antenna ports, or a single non-zero magnitude element. 
     In some embodiments of the method  320 , the UE  200  transmits data over three or antenna ports. For a data transmission on one spatial layer, the UE  200  transmits data on one or more of the antenna ports using a precoding matrix selected from a fourth set of precoding matrices configured for a second coherence capability. Each precoding matrix in the fourth set of precoding matrices comprises non-zero magnitude elements for all antenna ports. For a data transmission on two spatial layers the UE  200  transmits data on one or more of the antenna ports using a precoding matrix selected from a fifth set of precoding matrices configured for the second coherence capability. Each precoding matrix in the fifth set of precoding matrices comprises, for each spatial layer, one non-zero magnitude element corresponding to one of said first and second antenna ports, one non-zero magnitude element corresponding to a third antenna port, and zero magnitude elements for all remaining antenna ports. 
     In some embodiments of the method  320 , the first coherence capability corresponds to a partially coherent transmission capability. 
     In some embodiments of the method  320 , the second coherence capability corresponds to a fully coherent transmission capability. 
     In some embodiments of the method  320 , the first coherence capability corresponds to a fully coherent transmission capability. 
     Some embodiments of the method  320  further comprise indicating, by UE  200 , a coherence capability of the UE  200  to the base station  100 . In some embodiments, when the UE  200  indicates a coherence capability, the UE  200  transmits data transmission in accordance with the indicated coherence capability or a lower coherence capability 
       FIG.  9    illustrates an exemplary method  340  for transmitting data from the UE  200  to a base station  100  in a wireless communication network according to another embodiment. The method  340  is implemented by a UE  200  having multiple antenna ports connected to an antenna array. Generally, the UE  200  transmits data on one, two or three spatial layers. For a data transmission on one spatial layer, the UE  200  transmits data on one spatial layer using a precoding matrix selected from a first set of precoding matrices available for all coherence capabilities (block  345 ). Each precoding matrix in the first set of precoding matrices consists of a single non-zero element. For a data transmission on two spatial layers, the UE  200  transmits data on two spatial layers using a precoding matrix selected from a second set of precoding matrices available for all coherence capabilities (block  350 ). Each precoding matrix in the second set of precoding matrices comprises two non-zero elements in respective columns corresponding to the spatial layers. For a data transmission on three spatial layers or four spatial layers, the UE  200  transmits data using a precoding matrix selected from a third or fourth set of precoding matrices, respectively (block  355 ). Each precoding matrix in the third set consists of three non-zero elements, in respective columns corresponding to the spatial layers. Similarly, each precoding matrix in the fourth set consists of four non-zero elements, in respective columns corresponding to the spatial layers. 
     In some embodiments of the method  340 , the first, second and third sets of precoding matrices are available for all coherence capabilities. 
     In some embodiments of the method  340 , a number of precoding matrices in the first set equals the number of available antenna ports for data transmission. 
     In some embodiments of the method  340 , the number of precoding matrices in the second set equals the number of possible antenna port pairs of the available antenna ports; 
     In some embodiments of the method  340 , each precoding matrix in the fourth set consists of four non-zero elements, in respective columns corresponding to the spatial layers. 
       FIG.  10    illustrates an exemplary method  360  for transmitting data from the UE  200  to a base station  100  in a wireless communication network according to another embodiment. The method  490  is implemented by a UE  200  having multiple antenna ports connected to an antenna array. The UE  200  receives, from a base station, a first indication of a precoding matrix available for a non-coherent data transmission (block  365 ). The precoding matrix is selected from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers. The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices. The larger set of precoding matrices comprises precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. The UE  200  transmits data to the base station  100  using the selected precoding matrix (block  370 ). 
     In some embodiments of the method  360 , the UE  200  further receives a second indication of a precoding matrix available for a partially coherent data transmission, but not for a non-coherent data transmission. The precoding matrix is selected according to a number of spatial layers. For a data transmission on one spatial layer, the precoding matrix is selected from a fifth set of precoding matrices, which fifth set is available for partially coherent data transmissions but not for non-coherent data transmissions. Each precoding matrix in the fifth set of precoding matrices comprises two non-zero magnitude elements and at least one zero magnitude element. For a data transmission on two spatial layers, the precoding matrix is selected from a sixth set of precoding matrices, which sixth set is available for partially coherent data transmission but not for a non-coherent data transmission. Each precoding matrix in the sixth set of precoding matrices comprises a first and a second column corresponding to respective spatial layers and wherein each column comprises two non-zero magnitude elements and at least one zero magnitude element. The UE  200  transmits, in a second data transmission, data on two or more of the antenna ports using the precoding matrix indicated by the second indication. 
     In some embodiments of the method  360 , the UE  200  further receives a third indication of a precoding matrix available for a fully coherent data transmission, but not for a partially coherent data transmission or a non-coherent data transmission. For a data transmission on one spatial layer, the precoding matrix is selected from a seventh set of precoding matrices, which seventh set is available for fully coherent data transmissions but not for partially coherent or non-coherent data transmission. Each precoding matrix in the seventh set of precoding matrices comprises three or more non-zero magnitude elements. The UE  200  transmits, in a third data transmission, data on three or more of the antenna ports using the precoding matrix indicated by the third indication. 
     In some embodiments of the method  360 , the precoding matrix is selected from one of an eighth and ninth set of precoding matrices available for a fully coherent data transmission on two or three spatial layers. The eighth and ninth sets of precoding matrices comprise downlink precoding matrices obtainable according to a predetermined construction rule for constructing rank 2 and rank 3 downlink precoders. The predetermined construction rule uses an oversampling factor of 2. The eighth set of precoding matrices comprises fewer than 32 precoding matrices. In some embodiments, the construction rule comprises a construction that was first used in NR for 3GPP release 15 for rank 2 and rank 3 downlink precoders, respectively, wherein the construction uses an oversampling factor, O, set to O=2 and a variable, i1,3, set to i1,3=0. 
     In some embodiments of the method  360 , the precoding matrix is selected from a tenth set of precoding matrices, which tenth set is available for fully coherent data transmission but not for partially coherent or non-coherent data transmission. Each precoding matrix in the tenth set of precoding matrices comprises a first and a second column corresponding to respective spatial layers, wherein each column comprises two non-zero magnitude elements. The third data transmission comprises a data transmission on two spatial layers on three or more of the antenna ports. 
     In some embodiments of the method  360 , the UE  200  further receives a second indication of a precoding matrix configured for a partially coherent data transmission. The precoding matrix is selected according to a number of spatial layers. For a data transmission on one spatial layer, the precoding matrix is selected from a fifth set of precoding matrices configured for a partially coherent data transmission. At least one precoding matrix in the fifth set of precoding matrices comprises two non-zero magnitude elements corresponding to first and second antenna ports and one or more zero magnitude elements corresponding to all remaining antenna ports. For a data transmission on two spatial layers, the precoding matrix is selected from a sixth set of precoding matrices configured for a partially coherent data transmission. Each precoding matrix in the sixth set of precoding matrices comprises a first and a second column corresponding to respective spatial layers and wherein each column comprises two non-zero magnitude elements and at least one zero magnitude element. The UE  200  transmits, in a second data transmission, data on one or more of the antenna ports using the precoding matrix indicated by the second indication. 
     In some embodiments, each precoding matrix in the sixth set of precoding matrices is equivalent to a corresponding precoding matrix in a set of legacy uplink precoding matrices for rank 2 with a pair of rows of the legacy precoding matrix being swapped, the legacy precoding matrices being matrices used in LTE release 10 for transmission by UEs  200 . 
     In some embodiments of the method  360 , the precoding matrix for the second data transmission is selected from an eleventh set of precoding matrices. Each precoding matrix in the eleventh set of precoding matrices comprises, for each spatial layer, two non-zero magnitude elements corresponding to the first and second antenna ports and zero magnitude elements corresponding to all remaining antenna ports, or a single non-zero magnitude element. 
     In some embodiments of the method  360 , the UE  200  further receives a third indication of a precoding matrix configured for a fully coherent data transmission. The precoding matrix is selected according to a number of spatial layers. For a data transmission on one spatial layer, the precoding matrix is selected from a twelfth set of precoding matrices. Each precoding matrix in the twelfth set of precoding matrices comprises non-zero magnitude elements for all antenna ports. The UE  200  transmits, in a third data transmission, data on one or more of the antenna ports using the precoding matrix indicated by the third indication. 
     In some embodiments of the method  360 , the UE  200  further indicates a coherence capability of the UE  200  to the base station  100  for a data transmission. In one examples, the data transmission is in accordance with the indicated coherence capability. In another examples, the data transmission is in accordance with the indicated coherence capability or a lower coherence capability. 
       FIG.  11    illustrates an exemplary method  500  implemented by the UE  200  for receiving signaling from a base station  100  in a wireless communication network indicating a precoder matrix for an uplink transmission. The method  500  is implemented by a UE  200  having multiple antenna ports connected to an antenna array. The UE  200  receives a control message from a base station  100  including a precoding matrix indication field configurable to at least a first and second configuration (block  505 ). The first configuration of the precoding matrix indication field identifies precoding matrices in both a first set and a second set of precoding matrices, where the first and second set of precoding matrices correspond to a first and second coherence capability, respectively (block  510 ). The second configuration of the precoding matrix indication field identifies precoding matrices in the second set of precoding matrices, but not the first set of precoding matrices (block  515 ). 
     In some embodiments of the method  500  the UE  200  transmits data over two or more antenna ports according to a precoding matrix indicated by a precoding matrix indicator contained in the precoding matrix indicator field. 
     In some embodiments of the method  500 , the control message is received in higher protocol layer signaling, such as Radio Resource Control (RRC) signaling. 
       FIG.  12    illustrates an exemplary method  520  for indicating a coherence capability for a data transmission from the UE  200  to a base station  100  in a wireless communication network. The method  380  is implemented by UE  200  having multiple antenna ports connected to an antenna array. The UE  200  provides one or more of 1) an indication to a base station  100  of at least one subset of antenna ports on which the user equipment is capable of coherent transmission (block  525 ); 2) an indication to the base station  100  of one or more subsets of precoding matrices that the user equipment can use for transmission (block  530 ); or 3) an indication to the base station  100  of one or more antenna port pairs over which the user equipment can transmit coherently (block  535 ). 
     In some embodiments of the method  520 , the indication of a subset of antenna ports on which the user equipment is capable of coherent transmission comprises an indication, for each of two or more frequency bands, of the antenna ports on which the user equipment is capable of coherent transmission for the respective frequency band. 
     In some embodiments of the method  520 , the indication of the number of subsets of precoding matrices that the user equipment can use for transmission comprises an indication, for each of two or more frequency bands, of the number of subsets of precoding matrices that the user equipment can use for the respective frequency band. 
     In some embodiments of the method  520 , the indication of a number of antenna port pair over which the user equipment can transmit coherently comprises an indication, for each of two or more frequency bands, of the number of antenna port pairs over which the user equipment can transmit coherently for the respective frequency band. 
     Some embodiments of the method  520  further comprise transmitting data over two or more antenna ports according to the indication. 
       FIGS.  13 - 18    illustrate complementary methods performed by a base station  100  corresponding respectively to the methods of  FIGS.  7 - 12    respectively. 
       FIG.  13    illustrates an exemplary method  400  implemented by a base station  100  in a wireless communication network  10  for receiving data from the UE  200 . For a data transmission on one spatial layer, the base station  100  receives data transmitted by the UE  200  over two or more of the antenna ports using a precoding matrix selected from a first set of precoding matrices, which is available for the first coherence capability but not a lower second coherence capability (block  405 ). Each precoding matrix in the first set of precoding matrices consists of two non-zero magnitude elements and at least one zero magnitude element. For a data transmission on two spatial layers, the base station  100  receives data transmitted by the UE  200  over two or more of the antenna ports using a precoding matrix selected from the second set of precoding matrices, which is available for the first coherence capability but not for the lower second coherence capability (block  410 ). Each precoding matrix in the second set of precoding matrices comprises a first and a second column corresponding to respective spatial layers wherein each column consists of two non-zero magnitude elements and at least one zero magnitude element (block  415 ). 
       FIG.  14    illustrates an exemplary method  420  implemented by a base station  100  in a wireless communication network for receiving data from the UE  200 . For a data transmission on one spatial layer, the base station  100  receives data transmitted by the UE  200  on one or more of the antenna ports using a precoding matrix selected from a first set of precoding matrices configured for a first coherence capability (block  425 ). At least one precoding matrix in the first set of precoding matrices comprises two non-zero magnitude elements corresponding to first and second antenna ports and one or more zero magnitude elements corresponding to all remaining antenna ports. For a data transmission on two spatial layers, the base station  100  receives data transmitted by the UE  200  on one or more of the antenna elements using a precoding matrix selected from a second set of precoding matrices configured for the first coherence capability (block  430 ). Each precoding matrix in the second set of precoding matrices comprises, for each spatial layer, two non-zero magnitude elements corresponding to the first and second antenna ports and one or more zero magnitude elements corresponding to all remaining antenna ports, or zero magnitude elements corresponding to the first and second antenna ports respectively. 
       FIG.  15    illustrates an exemplary method  440  implemented by a base station  100  in a wireless communication network for receiving data from the UE  200 . For a data transmission on one spatial layer, the base station  100  receives data transmitted by the UE  200  on one spatial layer using a precoding matrix selected from a first set of precoding matrices available for all coherence capabilities (block  445 ). Each precoding matrix in the first set of precoding matrices consists of a single non-zero element. For a data transmission on two spatial layers, the base station  100  receives data transmitted by the UE  200  on two spatial layers using a precoding matrix selected from a second set of precoding matrices available for all coherence capabilities (block  450 ). Each precoding matrix in the second set of precoding matrices comprises two non-zero elements in respective columns corresponding to the spatial layers. For a data transmission on three spatial layers or four spatial layers, the base station  100  receives data transmitted by the UE  200  using a precoding matrix selected from a third or fourth set of precoding matrices, respectively (block  455 ). Each precoding matrix in the third set consists of three non-zero elements, in respective columns corresponding to the spatial layers. Similarly, each precoding matrix in the fourth set consists of four non-zero elements, in respective columns corresponding to the spatial layers. 
       FIG.  16    illustrates an exemplary method  460  implemented by a base station  100  in a wireless communication network  10  for receiving data from the UE  200 . The base station  100  selects, for a first data transmission, a precoding matrix from a respective first, second, third, or fourth set of precoding matrices according to a number of spatial layers (block  465 ). The first, second, third, and fourth sets of precoding matrices are available for all coherence capabilities and are comprised within a larger set of precoding matrices. The larger set of precoding matrices comprises precoding matrices that are not available for all coherence capabilities. The first, second, third, and fourth sets of precoding matrices correspond to one, two, three, or four spatial layers, respectively. The number of columns in the selected precoding matrix is equal to the number of spatial layers and each column comprises a single non-zero element and one or more zero elements. The base station  100  further transmits an indication of the selected precoding matrix to UE  200  (block  470 ). The base station  100  further receives the first data transmission, the data being transmitted by the UE  200  over one or more antenna ports using the precoding matrix selected for the first data transmission (block  475 ). 
     In some embodiments of the method  460 , the base station  100  selects, for a second data transmission, a precoding matrix available for a first coherence capability but not for a lower coherence capability according to a number of spatial layers. For a data transmission on one spatial layer, the base station  100  selects the precoding matrix for the second data transmission from a fifth set of precoding matrices, which fifth set is available for a first coherence capability but not for a lower second coherence capability. Each precoding matrix in the fifth set of precoding matrices comprises two non-zero magnitude elements and at least one zero magnitude element. For a data transmission on two spatial layers, the base station  100  receives data transmitted by the UE  200  over the two or more of the antenna ports using a precoding matrix selected from a sixth set of precoding matrices, which sixth set is available for the first coherence capability but not for a lower second coherence capability. Each precoding matrix in the sixth set of precoding matrices comprises a first and a second column corresponding to respective spatial layers wherein each column comprises two non-zero magnitude elements and at least one zero magnitude element. The non-zero magnitude elements represent weights to be applied to respective antenna ports and the zero magnitude elements represent not-transmitting antenna ports. The base station  100  further transmits an indication of the precoding matrix selected for the second data transmission to UE  200  and receives the second data transmission, the data being transmitted by the UE  200  over two or more antenna ports using the precoding matrix selected for the second data transmission. 
     In some embodiments of the method  460 , the base station  100  selects, for a second data transmission, a precoding matrix configured fora partially coherent precoding matrix according to a number of spatial layers. For a partially coherent data transmission on one spatial layer, the base station  100  receives data transmitted by the UE  200  over one or more of the antenna ports using a precoding matrix selected from a fifth set of precoding matrices configured for partially coherent data transmission. At least one precoding matrix in the fifth set of precoding matrices comprises two non-zero magnitude elements corresponding to first and second antenna ports and one or more zero magnitude element corresponding to all remaining antenna ports. For a partially coherent data transmission on two spatial layers, the base station  100  receives data transmitted by the UE  200  over one or more of the antenna ports using a precoding matrix selected from a sixth set of precoding matrices configured for partially coherent data transmission. Each precoding matrix in the sixth set of precoding matrices comprises, for each spatial layer, two non-zero magnitude elements corresponding to the first and second antenna ports and one or more zero magnitude element corresponding to all remaining antenna ports, or zero magnitude elements corresponding to the first and second antenna ports respectively. The base station  100  further transmits an indication of the precoding matrix selected for the second data transmission to UE  200  and receives the second data transmission, the data being transmitted by the UE  200  over two or more antenna ports using the precoding matrix selected for the second data transmission. 
     In some embodiments of the method  460 , the base station  100  receives data transmitted by the UE  200  on one spatial layer using a precoding matrix selected from a first set of precoding matrices available for all coherence capabilities, wherein each precoding matrix in the first set of precoding matrices comprises a single non-zero element. The base station  100  further receives data transmitted by the UE  200  on two spatial layers using a precoding matrix selected from a second set of precoding matrices available for all coherence capabilities, wherein each precoding matrix in the second set of precoding matrices comprises two non-zero elements in respective columns corresponding to the spatial layers. The base station  100  further receives data transmitted by the UE  200  on three spatial layers or four spatial layers using a precoding matrix selected from a third or fourth set, respectively. Each precoding matrix in the third set comprises three non-zero elements, in respective columns corresponding to the spatial layers. 
     In some embodiments of the method  460 , the base station  100  receives an indication from the UE  200  of a coherence capability of the UE  200  for a data transmission. In one examples, the data transmission received by the base station  100  is in accordance with the indicated coherence capability. In another examples, the data transmission received by the base station  100  is in accordance with the indicated coherence capability or a lower coherence capability. 
       FIG.  17    illustrates an exemplary method  540  implemented by a base station  100  in a wireless communication network  10  for signaling a precoding matrix to use for an uplink transmission to the UE  200 . The base station  100  transmits a control message to the UE  200  including a precoding matrix indication field configurable to at least a first and second configuration (block  545 ). The first configuration of the precoding matrix indication field identifies precoding matrices in both a first set and a second set of precoding matrices, where the first and second set of precoding matrices correspond to a first and second coherence capability, respectively (block  550 ). The second configuration of the precoding matrix indication field identifies precoding matrices in the second set of precoding matrices, but not the first set of precoding matrices (block  555 ). 
       FIG.  18    illustrates an exemplary method  560  implemented by a base station  100  in a wireless communication network  10  for receiving a coherence capability from the UE  200 . The base station  100  receives, from the UE  200 , one or more of 1) an indication to a base station  100  of at least one subset of antenna ports on which the user equipment is capable of coherent transmission (block  565 ); 2) an indication of one or more subsets of precoding matrices that the user equipment can use for transmission (block  570 ); or an indication of one or more antenna port pairs over which the user equipment can transmit coherently (block  575 ). 
     An apparatus can be configured to perform any of the methods herein described by implementing any functional means, modules, units, or circuitry. In one embodiment, for example, the apparatus comprise respective circuits or circuitry configured to perform the steps shown in the method figures. The circuits or circuitry in this regard may comprise circuits dedicated to performing certain functional processing and/or one or more microprocessors in conjunction with memory. For instance, the circuitry may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory may include program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein, in several embodiments. In embodiments that employ memory, the memory stores program code that, when executed by the one or more processors, carries out the techniques described herein. 
       FIG.  19    illustrates a UE  200  in accordance with one or more embodiments. The UE  400  comprises an antenna array  210  coupled to a plurality of antenna ports  205  and having multiple antenna elements  215 , a UL signaling module  220  for signaling a coherence capability to the base station  100 , a DL signaling module  230  for receiving the TPMI from the base station  100  for an uplink transmission, and a transmit module  240  for transmitting data to the base station  100  over one or more antenna ports  205  on an uplink channel, e.g., Physical Uplink Shared Channel (PUSCH). The various modules  220 ,  230 , and  240  can be implemented by hardware and/or by software code that is executed by a processor or processing circuit. The UE  200  of  FIG.  19    can be configured to perform any of the methods of  FIGS.  7 - 12   . 
       FIG.  20    illustrates a base station  100  in accordance with one or more embodiments. The base station  100  comprises an antenna array  110  coupled to a plurality of antenna parts  115  and having multiple antenna elements  115 , an UL signaling module  120  for receiving an indication from the UE  200  of the UE coherence capability, DL signaling module  120  for signaling the TPMI to the UE  200  for an uplink transmission, a DCI transmitting module  130  for transmitting DCI to the UE  200  on the primary DL carrier, and a receive module  140  for receiving UL data transmissions from the UE  200  on an uplink channel, e.g., PUSCH. The various modules  120 ,  130 , and  140  can be implemented by hardware and/or by software code that is executed by a processor or processing circuit. The base station  100  of  FIG.  20    can be configured to perform any of the methods of  FIGS.  13 - 18   . 
       FIG.  21    illustrates a wireless terminal  600  according to one embodiment that may be configured to function as a base station  100  or UE  200  as herein described. The wireless terminal  600  comprises an antenna array  510  coupled to a plurality of antenna parts  605  multiple antenna elements  615 , an interface circuit  620 , a processing circuit  630 , and memory  690 . 
     The interface circuit  620620  is coupled to the antenna array  610  and comprises the radio frequency (RF) circuitry needed for transmitting and receiving signals over a wireless communication channel. The interface circuit  620  provides a plurality of antenna ports  505  for spatial multiplexing transmissions. The processing circuit  630  controls the overall operation of the wireless terminal  500  and processes the signals transmitted to or received by the wireless terminal  500 . Such processing includes coding and modulation of transmitted data signals, and the demodulation and decoding of received data signals. The processing circuit  630  may comprise one or more microprocessors, hardware, firmware, or a combination thereof. 
     Memory  690  comprises both volatile and non-volatile memory for storing computer program code and data needed by the processing circuit  630  for operation. Memory  690  may comprise any tangible, non-transitory computer-readable storage medium for storing data including electronic, magnetic, optical, electromagnetic, or semiconductor data storage. Memory  690  stores a computer program  695  comprising executable instructions that configure the processing circuit  630  to implement any of the methods according to  FIGS.  7 - 18    as described herein. In general, computer program instructions and configuration information are stored in a non-volatile memory, such as a read only memory (ROM), erasable programmable read only memory (EPROM) or flash memory. Temporary data generated during operation may be stored in a volatile memory, such as a random access memory (RAM). In some embodiments, computer program  695  for configuring the processing circuit  630  as herein described may be stored in a removable memory, such as a portable compact disc, portable digital video disc, or other removable media. The computer program  695  may also be embodied in a carrier such as an electronic signal, optical signal, radio signal, or computer readable storage medium. 
     Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in  FIG.  22   . For simplicity, the wireless network of  FIG.  22    only depicts network  1106 , network nodes  1160  and  1160   b , and WDs  1110 ,  1110   b , and  1110   c . In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node  1160  and wireless device (WD)  1110  are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices&#39; access to and/or use of the services provided by, or via, the wireless network. 
     The wireless network may comprise and/or interface with any type of communication, telecommunication, data, cellular, and/or radio network or other similar type of system. In some embodiments, the wireless network may be configured to operate according to specific standards or other types of predefined rules or procedures. Thus, particular embodiments of the wireless network may implement communication standards, such as Long Term Evolution (LTE), New Radio, Narrowband Internet of Things (NB-IoT), and/or other suitable 4G or 5G or higher standards and/or any other appropriate wireless communication standard. 
     Network  1106  may comprise one or more backhaul networks, core networks, IP networks, public switched telephone networks (PSTNs), packet data networks, optical networks, wide-area networks (WANs), local area networks (LANs), wireless local area networks (WLANs), wired networks, wireless networks, metropolitan area networks, and other networks to enable communication between devices. 
     Network node  1160  and WD  1110  comprise various components described in more detail below. These components work together in order to provide network node and/or wireless device functionality, such as providing wireless connections in a wireless network. In different embodiments, the wireless network may comprise any number of wired or wireless networks, network nodes, base stations, controllers, wireless devices, relay stations, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections. 
     As used herein, network node refers to equipment capable, configured, arranged and/or operable to communicate directly or indirectly with a wireless device and/or with other network nodes or equipment in the wireless network to enable and/or provide wireless access to the wireless device and/or to perform other functions (e.g., administration) in the wireless network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)). Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and may then also be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS). Yet further examples of network nodes include multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell/multicast coordination entities (MCEs), core network nodes (e.g., MSCs, MMEs), O&amp;M nodes, OSS nodes, SON nodes, positioning nodes (e.g., E-SMLCs), and/or MDTs. As another example, a network node may be a virtual network node as described in more detail below. More generally, however, network nodes may represent any suitable device (or group of devices) capable, configured, arranged, and/or operable to enable and/or provide a wireless device with access to the wireless network or to provide some service to a wireless device that has accessed the wireless network. 
     In  FIG.  22   , network node  1160  includes processing circuitry  1170 , device readable medium  1180 , interface  1190 , auxiliary equipment  1184 , power source  1186 , power circuitry  1187 , and antenna  1162 . Although network node  1160  illustrated in the example wireless network of  FIG.  22    may represent a device that includes the illustrated combination of hardware components, other embodiments may comprise network nodes with different combinations of components. It is to be understood that a network node comprises any suitable combination of hardware and/or software needed to perform the tasks, features, functions and methods disclosed herein. Moreover, while the components of network node  1160  are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, a network node may comprise multiple different physical components that make up a single illustrated component (e.g., device readable medium  1180  may comprise multiple separate hard drives as well as multiple RAM modules). 
     Similarly, network node  1160  may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which network node  1160  comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, network node  1160  may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate device readable medium  1180  for the different RATs) and some components may be reused (e.g., the same antenna  1162  may be shared by the RATs). Network node  1160  may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node  1160 , such as, for example, GSM, WCDMA, LTE, NR, WiFi, or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node  1160 . 
     Processing circuitry  1170  is configured to perform any determining, calculating, or similar operations (e.g., certain obtaining operations) described herein as being provided by a network node. These operations performed by processing circuitry  1170  may include processing information obtained by processing circuitry  1170  by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. 
     Processing circuitry  1170  may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other network node  1160  components, such as device readable medium  1180 , network node  1160  functionality. For example, processing circuitry  1170  may execute instructions stored in device readable medium  1180  or in memory within processing circuitry  1170 . Such functionality may include providing any of the various wireless features, functions, or benefits discussed herein. In some embodiments, processing circuitry  1170  may include a system on a chip (SOC). 
     In some embodiments, processing circuitry  1170  may include one or more of radio frequency (RF) transceiver circuitry  1172  and baseband processing circuitry  1174 . In some embodiments, radio frequency (RF) transceiver circuitry  1172  and baseband processing circuitry  1174  may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry  1172  and baseband processing circuitry  1174  may be on the same chip or set of chips, boards, or units 
     In certain embodiments, some or all of the functionality described herein as being provided by a network node, base station, eNB or other such network device may be performed by processing circuitry  1170  executing instructions stored on device readable medium  1180  or memory within processing circuitry  1170 . In alternative embodiments, some or all of the functionality may be provided by processing circuitry  1170  without executing instructions stored on a separate or discrete device readable medium, such as in a hard-wired manner. In any of those embodiments, whether executing instructions stored on a device readable storage medium or not, processing circuitry  1170  can be configured to perform the described functionality. The benefits provided by such functionality are not limited to processing circuitry  1170  alone or to other components of network node  1160 , but are enjoyed by network node  1160  as a whole, and/or by end users and the wireless network generally. 
     Device readable medium  1180  may comprise any form of volatile or non-volatile computer readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by processing circuitry  1170 . Device readable medium  1180  may store any suitable instructions, data or information, including a computer program, software, an application including one or more of logic, rules, code, tables, etc. and/or other instructions capable of being executed by processing circuitry  1170  and, utilized by network node  1160 . Device readable medium  1180  may be used to store any calculations made by processing circuitry  1170  and/or any data received via interface  1190 . In some embodiments, processing circuitry  1170  and device readable medium  1180  may be considered to be integrated. 
     Interface  1190  is used in the wired or wireless communication of signaling and/or data between network node  1160 , network  1106 , and/or WDs  1110 . As illustrated, interface  1190  comprises port(s)/terminal(s)  1194  to send and receive data, for example to and from network  1106  over a wired connection. Interface  1190  also includes radio front end circuitry  1192  that may be coupled to, or in certain embodiments a part of, antenna  1162 . Radio front end circuitry  1192  comprises filters  1198  and amplifiers  1196 . Radio front end circuitry  1192  may be connected to antenna  1162  and processing circuitry  1170 . Radio front end circuitry may be configured to condition signals communicated between antenna  1162  and processing circuitry  1170 . Radio front end circuitry  1192  may receive digital data that is to be sent out to other network nodes or WDs via a wireless connection. Radio front end circuitry  1192  may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters  1198  and/or amplifiers  1196 . The radio signal may then be transmitted via antenna  1162 . Similarly, when receiving data, antenna  1162  may collect radio signals which are then converted into digital data by radio front end circuitry  1192 . The digital data may be passed to processing circuitry  1170 . In other embodiments, the interface may comprise different components and/or different combinations of components. 
     In certain alternative embodiments, network node  1160  may not include separate radio front end circuitry  1192 , instead, processing circuitry  1170  may comprise radio front end circuitry and may be connected to antenna  1162  without separate radio front end circuitry  1192 . Similarly, in some embodiments, all or some of RF transceiver circuitry  1172  may be considered a part of interface  1190 . In still other embodiments, interface  1190  may include one or more ports or terminals  1194 , radio front end circuitry  1192 , and RF transceiver circuitry  1172 , as part of a radio unit (not shown), and interface  1190  may communicate with baseband processing circuitry  1174 , which is part of a digital unit (not shown). 
     Antenna  1162  may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. Antenna  1162  may be coupled to radio front end circuitry  1190  and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In some embodiments, antenna  1162  may comprise one or more omni-directional, sector or panel antennas operable to transmit/receive radio signals between, for example, 2 GHz and 66 GHz. An omni-directional antenna may be used to transmit/receive radio signals in any direction, a sector antenna may be used to transmit/receive radio signals from devices within a particular area, and a panel antenna may be a line of sight antenna used to transmit/receive radio signals in a relatively straight line. In some instances, the use of more than one antenna may be referred to as MIMO. In certain embodiments, antenna  1162  may be separate from network node  1160  and may be connectable to network node  1160  through an interface or port. 
     Antenna  1162 , interface  1190 , and/or processing circuitry  1170  may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by a network node. Any information, data and/or signals may be received from a wireless device, another network node and/or any other network equipment. Similarly, antenna  1162 , interface  1190 , and/or processing circuitry  1170  may be configured to perform any transmitting operations described herein as being performed by a network node. Any information, data and/or signals may be transmitted to a wireless device, another network node and/or any other network equipment. 
     Power circuitry  1187  may comprise, or be coupled to, power management circuitry and is configured to supply the components of network node  1160  with power for performing the functionality described herein. Power circuitry  1187  may receive power from power source  1186 . Power source  1186  and/or power circuitry  1187  may be configured to provide power to the various components of network node  1160  in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). Power source  1186  may either be included in, or external to, power circuitry  1187  and/or network node  1160 . For example, network node  1160  may be connectable to an external power source (e.g., an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry  1187 . As a further example, power source  1186  may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry  1187 . The battery may provide backup power should the external power source fail. Other types of power sources, such as photovoltaic devices, may also be used. 
     Alternative embodiments of network node  1160  may include additional components beyond those shown in  FIG.  2    that may be responsible for providing certain aspects of the network node&#39;s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, network node  1160  may include user interface equipment to allow input of information into network node  1160  and to allow output of information from network node  1160 . This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node  1160 . 
     As used herein, wireless device (WD) refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE). a vehicle-mounted wireless terminal device, etc. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (IoT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g. refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal. 
     As illustrated, wireless device  1110  includes antenna  1111 , interface  1114 , processing circuitry  1120 , device readable medium  1130 , user interface equipment  1132 , auxiliary equipment  1134 , power source  1136  and power circuitry  1137 . WD  1110  may include multiple sets of one or more of the illustrated components for different wireless technologies supported by WD  1110 , such as, for example, LTE, NR or NB-IoT wireless technologies, just to mention a few. These wireless technologies may be integrated into the same or different chips or set of chips as other components within WD  1110 . 
     Antenna  1111  may include one or more antennas or antenna arrays, configured to send and/or receive wireless signals, and is connected to interface  1114 . In certain alternative embodiments, antenna  1111  may be separate from WD  1110  and be connectable to WD  1110  through an interface or port. Antenna  1111 , interface  1114 , and/or processing circuitry  1120  may be configured to perform any receiving or transmitting operations described herein as being performed by a WD. Any information, data and/or signals may be received from a network node and/or another WD. In some embodiments, radio front end circuitry and/or antenna  1111  may be considered an interface. 
     As illustrated, interface  1114  comprises radio front end circuitry  1112  and antenna  1111 . Radio front end circuitry  1112  comprise one or more filters  1118  and amplifiers  1116 . Radio front end circuitry  1114  is connected to antenna  1111  and processing circuitry  1120 , and is configured to condition signals communicated between antenna  1111  and processing circuitry  1120 . Radio front end circuitry  1112  may be coupled to or a part of antenna  1111 . In some embodiments, WD  1110  may not include separate radio front end circuitry  1112 ; rather, processing circuitry  1120  may comprise radio front end circuitry and may be connected to antenna  1111 . Similarly, in some embodiments, some or all of RF transceiver circuitry  1122  may be considered a part of interface  1114 . Radio front end circuitry  1112  may receive digital data that is to be sent out to other network nodes or WDs via a wireless connection. Radio front end circuitry  1112  may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters  1118  and/or amplifiers  1116 . The radio signal may then be transmitted via antenna  1111 . Similarly, when receiving data, antenna  1111  may collect radio signals which are then converted into digital data by radio front end circuitry  1112 . The digital data may be passed to processing circuitry  1120 . In other embodiments, the interface may comprise different components and/or different combinations of components. 
     Processing circuitry  1120  may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software, and/or encoded logic operable to provide, either alone or in conjunction with other WD  1110  components, such as device readable medium  1130 , WD  1110  functionality. Such functionality may include providing any of the various wireless features or benefits discussed herein. For example, processing circuitry  1120  may execute instructions stored in device readable medium  1130  or in memory within processing circuitry  1120  to provide the functionality disclosed herein. 
     As illustrated, processing circuitry  1120  includes one or more of RF transceiver circuitry  1122 , baseband processing circuitry  1124 , and application processing circuitry  1126 . In other embodiments, the processing circuitry may comprise different components and/or different combinations of components. In certain embodiments processing circuitry  1120  of WD  1110  may comprise a SOC. In some embodiments, RF transceiver circuitry  1122 , baseband processing circuitry  1124 , and application processing circuitry  1126  may be on separate chips or sets of chips. In alternative embodiments, part or all of baseband processing circuitry  1124  and application processing circuitry  1126  may be combined into one chip or set of chips, and RF transceiver circuitry  1122  may be on a separate chip or set of chips. In still alternative embodiments, part or all of RF transceiver circuitry  1122  and baseband processing circuitry  1124  may be on the same chip or set of chips, and application processing circuitry  1126  may be on a separate chip or set of chips. In yet other alternative embodiments, part or all of RF transceiver circuitry  1122 , baseband processing circuitry  1124 , and application processing circuitry  1126  may be combined in the same chip or set of chips. In some embodiments, RF transceiver circuitry  1122  may be a part of interface  1114 . RF transceiver circuitry  1122  may condition RF signals for processing circuitry  1120 . 
     In certain embodiments, some or all of the functionality described herein as being performed by a WD may be provided by processing circuitry  1120  executing instructions stored on device readable medium  1130 , which in certain embodiments may be a computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by processing circuitry  1120  without executing instructions stored on a separate or discrete device readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a device readable storage medium or not, processing circuitry  1120  can be configured to perform the described functionality. The benefits provided by such functionality are not limited to processing circuitry  1120  alone or to other components of WD  1110 , but are enjoyed by WD  1110  as a whole, and/or by end users and the wireless network generally. 
     Processing circuitry  1120  may be configured to perform any determining, calculating, or similar operations (e.g., certain obtaining operations) described herein as being performed by a WD. These operations, as performed by processing circuitry  1120 , may include processing information obtained by processing circuitry  1120  by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored by WD  1110 , and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. 
     Device readable medium  1130  may be operable to store a computer program, software, an application including one or more of logic, rules, code, tables, etc. and/or other instructions capable of being executed by processing circuitry  1120 . Device readable medium  1130  may include computer memory (e.g., Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (e.g., a hard disk), removable storage media (e.g., a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device readable and/or computer executable memory devices that store information, data, and/or instructions that may be used by processing circuitry  1120 . In some embodiments, processing circuitry  1120  and device readable medium  1130  may be considered to be integrated. 
     User interface equipment  1132  may provide components that allow for a human user to interact with WD  1110 . Such interaction may be of many forms, such as visual, audial, tactile, etc. User interface equipment  1132  may be operable to produce output to the user and to allow the user to provide input to WD  1110 . The type of interaction may vary depending on the type of user interface equipment  1132  installed in WD  1110 . For example, if WD  1110  is a smart phone, the interaction may be via a touch screen; if WD  1110  is a smart meter, the interaction may be through a screen that provides usage (e.g., the number of gallons used) or a speaker that provides an audible alert (e.g., if smoke is detected). User interface equipment  1132  may include input interfaces, devices and circuits, and output interfaces, devices and circuits. User interface equipment  1132  is configured to allow input of information into WD  1110 , and is connected to processing circuitry  1120  to allow processing circuitry  1120  to process the input information. User interface equipment  1132  may include, for example, a microphone, a proximity or other sensor, keys/buttons, a touch display, one or more cameras, a USB port, or other input circuitry. User interface equipment  1132  is also configured to allow output of information from WD  1110 , and to allow processing circuitry  1120  to output information from WD  1110 . User interface equipment  1132  may include, for example, a speaker, a display, vibrating circuitry, a USB port, a headphone interface, or other output circuitry. Using one or more input and output interfaces, devices, and circuits, of user interface equipment  1132 , WD  1110  may communicate with end users and/or the wireless network, and allow them to benefit from the functionality described herein. 
     Auxiliary equipment  1134  is operable to provide more specific functionality which may not be generally performed by WDs. This may comprise specialized sensors for doing measurements for various purposes, interfaces for additional types of communication such as wired communications etc. The inclusion and type of components of auxiliary equipment  1134  may vary depending on the embodiment and/or scenario. 
     Power source  1136  may, in some embodiments, be in the form of a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic devices or power cells, may also be used. WD  1110  may further comprise power circuitry  1137  for delivering power from power source  1136  to the various parts of WD  1110  which need power from power source  1136  to carry out any functionality described or indicated herein. Power circuitry  1137  may in certain embodiments comprise power management circuitry. Power circuitry  1137  may additionally or alternatively be operable to receive power from an external power source; in which case WD  1110  may be connectable to the external power source (such as an electricity outlet) via input circuitry or an interface such as an electrical power cable. Power circuitry  1137  may also in certain embodiments be operable to deliver power from an external power source to power source  1136 . This may be, for example, for the charging of power source  1136 . Power circuitry  1137  may perform any formatting, converting, or other modification to the power from power source  1136  to make the power suitable for the respective components of WD  1110  to which power is supplied. 
       FIG.  23    illustrates one embodiment of a UE in accordance with various aspects described herein. As used herein, a user equipment or UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter). UE  1200  may be any UE identified by the 3rd Generation Partnership Project (3GPP), including a NB-IoT UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE. UE  1200 , as illustrated in  FIG.  23   , is one example of a WD configured for communication in accordance with one or more communication standards promulgated by the 3rd Generation Partnership Project (3GPP), such as 3GPP&#39;s LTE, and/or 5G standards. As mentioned previously, the term WD and UE may be used interchangeable. Accordingly, although  FIG.  23    is a UE, the components discussed herein are equally applicable to a WD, and vice-versa. 
     In  FIG.  23   , UE  1200  includes processing circuitry  1201  that is operatively coupled to input/output interface  1205 , radio frequency (RF) interface  1209 , network connection interface  1211 , memory  1215  including random access memory (RAM)  1217 , read-only memory (ROM)  1219 , and storage medium  1221  or the like, communication subsystem  1231 , power source  1233 , and/or any other component, or any combination thereof. Storage medium  1221  includes operating system  1223 , application program  1225 , and data  1227 . In other embodiments, storage medium  1221  may include other similar types of information. Certain UEs may utilize all of the components shown in  FIG.  23   , or only a subset of the components. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc. 
     In  FIG.  23   , processing circuitry  1201  may be configured to process computer instructions and data. Processing circuitry  1201  may be configured to implement any sequential state machine operative to execute machine instructions stored as machine-readable computer programs in the memory, such as one or more hardware-implemented state machines (e.g., in discrete logic, FPGA, ASIC, etc.); programmable logic together with appropriate firmware; one or more stored program, general-purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry  1201  may include two central processing units (CPUs). Data may be information in a form suitable for use by a computer. 
     In the depicted embodiment, input/output interface  1205  may be configured to provide a communication interface to an input device, output device, or input and output device. UE  1200  may be configured to use an output device via input/output interface  1205 . An output device may use the same type of interface port as an input device. For example, a USB port may be used to provide input to and output from UE  1200 . The output device may be a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. UE  1200  may be configured to use an input device via input/output interface  1205  to allow a user to capture information into UE  1200 . The input device may include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, another like sensor, or any combination thereof. For example, the input device may be an accelerometer, a magnetometer, a digital camera, a microphone, and an optical sensor. 
     In  FIG.  23   , RF interface  1209  may be configured to provide a communication interface to RF components such as a transmitter, a receiver, and an antenna. Network connection interface  1211  may be configured to provide a communication interface to network  1243   a . Network  1243   a  may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network  1243   a  may comprise a Wi-Fi network. Network connection interface  1211  may be configured to include a receiver and a transmitter interface used to communicate with one or more other devices over a communication network according to one or more communication protocols, such as Ethernet, TCP/IP, SONET, ATM, or the like. Network connection interface  1211  may implement receiver and transmitter functionality appropriate to the communication network links (e.g., optical, electrical, and the like). The transmitter and receiver functions may share circuit components, software or firmware, or alternatively may be implemented separately. 
     RAM  1217  may be configured to interface via bus  1202  to processing circuitry  1201  to provide storage or caching of data or computer instructions during the execution of software programs such as the operating system, application programs, and device drivers. ROM  1219  may be configured to provide computer instructions or data to processing circuitry  1201 . For example, ROM  1219  may be configured to store invariant low-level system code or data for basic system functions such as basic input and output (I/O), startup, or reception of keystrokes from a keyboard that are stored in a non-volatile memory. Storage medium  1221  may be configured to include memory such as RAM, ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, or flash drives. In one example, storage medium  1221  may be configured to include operating system  1223 , application program  1225  such as a web browser application, a widget or gadget engine or another application, and data file  1227 . Storage medium  1221  may store, for use by UE  1200 , any of a variety of various operating systems or combinations of operating systems. 
     Storage medium  1221  may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), floppy disk drive, flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as a subscriber identity module or a removable user identity (SIM/RUIM) module, other memory, or any combination thereof. Storage medium  1221  may allow UE  1200  to access computer-executable instructions, application programs or the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied in storage medium  1221 , which may comprise a device readable medium. 
     In  FIG.  23   , processing circuitry  1201  may be configured to communicate with network  1243   b  using communication subsystem  1231 . Network  1243   a  and network  1243   b  may be the same network or networks or different network or networks. Communication subsystem  1231  may be configured to include one or more transceivers used to communicate with network  1243   b . For example, communication subsystem  1231  may be configured to include one or more transceivers used to communicate with one or more remote transceivers of another device capable of wireless communication such as another WD, UE, or base station of a radio access network (RAN) according to one or more communication protocols, such as WCDMA, LTE, UTRAN, NR, or the like. Each transceiver may include transmitter  1233  and/or receiver  1235  to implement transmitter or receiver functionality, respectively, appropriate to the RAN links (e.g., frequency allocations and the like). Further, transmitter  1233  and receiver  1235  of each transceiver may share circuit components, software or firmware, or alternatively may be implemented separately. 
     In the illustrated embodiment, the communication functions of communication subsystem  1231  may include data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. For example, communication subsystem  1231  may include cellular communication, Wi-Fi communication, Bluetooth communication, and GPS communication. Network  1243   b  may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network  1243   b  may be a cellular network, a Wi-Fi network, and/or a near-field network. Power source  1213  may be configured to provide alternating current (AC) or direct current (DC) power to components of UE  1200 . 
     The features, benefits and/or functions described herein may be implemented in one of the components of UE  1200  or partitioned across multiple components of UE  1200 . Further, the features, benefits, and/or functions described herein may be implemented in any combination of hardware, software or firmware. In one example, communication subsystem  1231  may be configured to include any of the components described herein. Further, processing circuitry  1201  may be configured to communicate with any of such components over bus  1202 . In another example, any of such components may be represented by program instructions stored in memory that when executed by processing circuitry  1201  perform the corresponding functions described herein. In another example, the functionality of any of such components may be partitioned between processing circuitry  1201  and communication subsystem  1231 . In another example, the non-computationally intensive functions of any of such components may be implemented in software or firmware and the computationally intensive functions may be implemented in hardware. 
       FIG.  24    is a schematic block diagram illustrating a virtualization environment  1300  in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to a node (e.g., a virtualized base station or a virtualized radio access node) or to a device (e.g., a UE, a wireless device or any other type of communication device) or components thereof and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components (e.g., via one or more applications, components, functions, virtual machines or containers executing on one or more physical processing nodes in one or more networks). 
       FIG.  25    illustrates a telecommunication network connected via an intermediate network to a host computer in accordance with some embodiments. In particular, with reference to  FIG.  23   , in accordance with an embodiment, a communication system includes telecommunication network  1410 , such as a 3GPP-type cellular network, which comprises access network  1411 , such as a radio access network, and core network  1414 . Access network  1411  comprises a plurality of base stations  1412   a ,  1412   b ,  1412   c , such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area  1413   a ,  1413   b ,  1413   c . Each base station  1412   a ,  1412   b ,  1412   c  is connectable to core network  1414  over a wired or wireless connection  1415 . A first UE  1491  located in coverage area  1413   c  is configured to wirelessly connect to, or be paged by, the corresponding base station  1412   c . A second UE  1492  in coverage area  1413   a  is wirelessly connectable to the corresponding base station  1412   a . While a plurality of UEs  1491 ,  1492  are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station  1412 . 
     Telecommunication network  1410  is itself connected to host computer  1430 , which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. Host computer  1430  may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. Connections  1421  and  1422  between telecommunication network  1410  and host computer  1430  may extend directly from core network  1414  to host computer  1430  or may go via an optional intermediate network  1420 . Intermediate network  1420  may be one of, or a combination of more than one of, a public, private or hosted network; intermediate network  1420 , if any, may be a backbone network or the Internet; in particular, intermediate network  1420  may comprise two or more sub-networks (not shown). 
     The communication system of  FIG.  25    as a whole enables connectivity between the connected UEs  1491 ,  1492  and host computer  1430 . The connectivity may be described as an over-the-top (OTT) connection  1450 . Host computer  1430  and the connected UEs  1491 ,  1492  are configured to communicate data and/or signaling via OTT connection  1450 , using access network  1411 , core network  1414 , any intermediate network  1420  and possible further infrastructure (not shown) as intermediaries. OTT connection  1450  may be transparent in the sense that the participating communication devices through which OTT connection  1450  passes are unaware of routing of uplink and downlink communications. For example, base station  1412  may not or need not be informed about the past routing of an incoming downlink communication with data originating from host computer  1430  to be forwarded (e.g., handed over) to a connected UE  1491 . Similarly, base station  1412  need not be aware of the future routing of an outgoing uplink communication originating from the UE  1491  towards the host computer  1430 . 
     Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to  FIG.  26   .  FIG.  26    illustrates host computer communicating via a base station with a user equipment over a partially wireless connection in accordance with some embodiments. In communication system  1500 , host computer  1510  comprises hardware  1515  including communication interface  1516  configured to set up and maintain a wired or wireless connection with an interface of a different communication device of communication system  1500 . Host computer  1510  further comprises processing circuitry  1518 , which may have storage and/or processing capabilities. In particular, processing circuitry  1518  may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. Host computer  1510  further comprises software  1511 , which is stored in or accessible by host computer  1510  and executable by processing circuitry  1518 . Software  1511  includes host application  1512 . Host application  1512  may be operable to provide a service to a remote user, such as UE  1530  connecting via OTT connection  1550  terminating at UE  1530  and host computer  1510 . In providing the service to the remote user, host application  1512  may provide user data which is transmitted using OTT connection  1550 . 
     Communication system  1500  further includes base station  1520  provided in a telecommunication system and comprising hardware  1525  enabling it to communicate with host computer  1510  and with UE  1530 . Hardware  1525  may include communication interface  1526  for setting up and maintaining a wired or wireless connection with an interface of a different communication device of communication system  1500 , as well as radio interface  1527  for setting up and maintaining at least wireless connection  1570  with UE  1530  located in a coverage area (not shown in  FIG.  26   ) served by base station  1520 . Communication interface  1526  may be configured to facilitate connection  1560  to host computer  1510 . Connection  1560  may be direct or it may pass through a core network (not shown in  FIG.  26   ) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, hardware  1525  of base station  1520  further includes processing circuitry  1528 , which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. Base station  1520  further has software  1521  stored internally or accessible via an external connection. 
     Communication system  1500  further includes UE  1530  already referred to. Its hardware  1535  may include radio interface  1537  configured to set up and maintain wireless connection  1570  with a base station serving a coverage area in which UE  1530  is currently located. Hardware  1535  of UE  1530  further includes processing circuitry  1538 , which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. UE  1530  further comprises software  1531 , which is stored in or accessible by UE  1530  and executable by processing circuitry  1538 . Software  1531  includes client application  1532 . Client application  1532  may be operable to provide a service to a human or non-human user via UE  1530 , with the support of host computer  1510 . In host computer  1510 , an executing host application  1512  may communicate with the executing client application  1532  via OTT connection  1550  terminating at UE  1530  and host computer  1510 . In providing the service to the user, client application  1532  may receive request data from host application  1512  and provide user data in response to the request data. OTT connection  1550  may transfer both the request data and the user data. Client application  1532  may interact with the user to generate the user data that it provides. 
     It is noted that host computer  1510 , base station  1520  and UE  1530  illustrated in  FIG.  26    may be similar or identical to host computer  1430 , one of base stations  1412   a ,  1412   b ,  1412   c  and one of UEs  1491 ,  1492  of  FIG.  25   , respectively. This is to say, the inner workings of these entities may be as shown in  FIG.  26    and independently, the surrounding network topology may be that of  FIG.  25   . 
     In  FIG.  26   , OTT connection  1550  has been drawn abstractly to illustrate the communication between host computer  1510  and UE  1530  via base station  1520 , without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from UE  1530  or from the service provider operating host computer  1510 , or both. While OTT connection  1550  is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network). 
     Wireless connection  1570  between UE  1530  and base station  1520  is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to UE  1530  using OTT connection  1550 , in which wireless connection  1570  forms the last segment. More precisely, the teachings of these embodiments may improve the latency of data transmissions and thereby provide benefits such as reduced waiting time, particularly for machine control applications. 
     A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring OTT connection  1550  between host computer  1510  and UE  1530 , in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring OTT connection  1550  may be implemented in software  1511  and hardware  1515  of host computer  1510  or in software  1531  and hardware  1535  of UE  1530 , or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which OTT connection  1550  passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software  1511 ,  1531  may compute or estimate the monitored quantities. The reconfiguring of OTT connection  1550  may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect base station  1520 , and it may be unknown or imperceptible to base station  1520 . Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating host computer  1510 &#39;s measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that software  1511  and  1531  causes messages to be transmitted, in particular empty or ‘dummy’ messages, using OTT connection  1550  while it monitors propagation times, errors etc. 
       FIG.  27    is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to  FIGS.  14  and  15   . For simplicity of the present disclosure, only drawing references to  FIG.  16    will be included in this section. In step  1610 , the host computer provides user data. In substep  1611  (which may be optional) of step  1610 , the host computer provides the user data by executing a host application. In step  1620 , the host computer initiates a transmission carrying the user data to the UE. In step  1630  (which may be optional), the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step  1640  (which may also be optional), the UE executes a client application associated with the host application executed by the host computer. 
       FIG.  28    is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to  FIGS.  14  and  15   . For simplicity of the present disclosure, only drawing references to  FIG.  17    will be included in this section. In step  1710  of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In step  1720 , the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In step  1730  (which may be optional), the UE receives the user data carried in the transmission. 
       FIG.  29    is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to  FIGS.  25  and  26   . For simplicity of the present disclosure, only drawing references to  FIG.  27    will be included in this section. In step  1810  (which may be optional), the UE receives input data provided by the host computer. Additionally or alternatively, in step  1820 , the UE provides user data. In substep  1821  (which may be optional) of step  1820 , the UE provides the user data by executing a client application. In substep  1811  (which may be optional) of step  1810 , the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in substep  1830  (which may be optional), transmission of the user data to the host computer. In step  1840  of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure. 
       FIG.  30    is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to  FIGS.  25  and  26   . For simplicity of the present disclosure, only drawing references to  FIG.  28    will be included in this section. In step  1910  (which may be optional), in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In step  1920  (which may be optional), the base station initiates transmission of the received user data to the host computer. In step  1930  (which may be optional), the host computer receives the user data carried in the transmission initiated by the base station. 
     Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure. 
     Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the description. 
     The term unit may have conventional meaning in the field of electronics, electrical devices and/or electronic devices and may include, for example, electrical and/or electronic circuitry, devices, modules, processors, memories, logic solid state and/or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and/or displaying functions, and so on, as such as those that are described herein. 
     Some of the embodiments contemplated herein are described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein. The disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art. 
     The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.