Patent Publication Number: US-2022224384-A1

Title: Network node and method in a wireless communications network

Description:
TECHNICAL FIELD 
     Embodiments herein relate to a network node and a methods therein. In particular, they relate to handling a Single User (SU) Multiple Input Multiple Output (MIMO) transmission from a User Equipment (UE) in a wireless communications network. 
     BACKGROUND 
     In a typical wireless communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STA) and/or user equipment (UE), communicate via a Local Area Network such as a WiFi network or a Radio Access Network (RAN) to one or more core networks (CN). The RAN covers a geographical area which is divided into service areas or cell areas, which may also be referred to as a beam or a beam group, with each service area or cell area being served by a radio network node such as a radio access node e.g., a W-Fi access point or a radio base station (RBS), which in some networks may also be denoted, for example, a NodeB, eNodeB (eNB), or gNB as denoted in 5th Generation (5G). A service area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node communicates over an air interface operating on radio frequencies with the wireless device within range of the radio network node. The radio network node communicates to the wireless device in DownLink (DL) and from the wireless device in UpLink (UL). 
     Specifications for the Evolved Packet System (EPS), also called a Fourth Generation (4G) network, have been completed within the 3rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases, for example to specify a Fifth Generation (5G) network also referred to as 5G New Radio (NR). The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long Term Evolution (LTE) radio access network, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network. E-UTRAN/LTE is a variant of a 3GPP radio access network wherein the radio network nodes are directly connected to the EPC core network rather than to RNCs used in 3rd Generation (3G) networks. In general, in E-UTRAN/LTE the functions of a 3G RNC are distributed between the radio network nodes, e.g. eNodeBs in LTE, and the core network. As such, the RAN of an EPS has an essentially “flat” architecture comprising radio network nodes connected directly to one or more core networks, i.e. they are not connected to RNCs. To compensate for that, the E-UTRAN specification defines a direct interface between the radio network nodes, this interface being denoted the X2 interface. 
     Multi-antenna techniques can 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/or related techniques are commonly referred to as MIMO. 
     In addition to faster peak Internet connection speeds, 5G planning aims at higher capacity than current 4G, allowing higher number of mobile broadband users per area unit, and allowing consumption of higher or unlimited data quantities in gigabyte per month and user. This would make it feasible for a large portion of the population to stream high-definition media many hours per day with their mobile devices, when out of reach of Wi-Fi hotspots. 5G research and development also aims at improved support of machine to machine communication, also known as the Internet of things, aiming at lower cost, lower battery consumption and lower latency than 4G equipment. 
     Beamforming and 5G 
     Multi-antenna systems allow transmitting signals that are focused towards certain spatial regions. This creates beams, also referred to as beam forming, whose coverage may reach beyond transmissions using non-beamformed signals but at the cost of narrower coverage. This is a classic trade-off between distance and angular coverage. 
     In 5G, radio devices are expected to operate with a large number of antennas referred to as Massive MIMO, offering flexibility and potentially very narrow beams, i.e. with very large focusing gain. Massive MIMO makes a clean break with current practice through the use of a very large number of service antennas that are operated fully coherently and adaptively. 
     MIMO or Massive MIMO is the a very important technology in both LTE and NR. Uplink Single User (SU) MIMO becomes more and more important since multiple transmission antennas in the UE side will be supported to get spatial multiplexing gain. Single User (SU) MIMO when used herein means a single UE using multiple antennas to transmit uplink data. 
     Currently, a rank and precoding matrix or precoding matrix indicator (PMI) for uplink SU MIMO is based on reception of Sounding Reference Signals (SRS). The wording rank when used herein means the number of parallel data streams transmitted by the UE. The wording precoding matrix when used herein means the matrix used by the UE for the precoding of the uplink transmission. 
     The wording PMI when used herein means the precoding matrix indicator to indicate the precoding matrix which is typically sent from network node to the UE. 
     The SRS may include the whole uplink channel matrix information. The whole uplink channel matrix information when used herein means the channel matrices over the whole bandwidth, herein each channel matrix comprises the channel responses for all the antenna pairs, and each antenna pair means one UE antenna and one network node antenna. However, in both LTE and NR, the SRS capacity is limited, and SRS coverage is also a system limitation. 
     SUMMARY 
     An object of embodiments herein is to improve the performance of a wireless communications network using SU MIMO transmissions. 
     According to a first aspect of embodiments herein, the object is achieved by a method performed by a network node for handling a Single User, SU, Multiple Input Multiple Output, MIMO, transmission from a User Equipment, UE, in a wireless communications network. The network node selects an allowed precoding matrix set for the SU MIMO transmission. The network node further estimates a raw covariance matrix for the SU MIMO transmission, based on a Demodulation Reference Signal, DMRS, of a Physical Uplink Shared Channel, PUSCH, received from the UE  120 . The network node then selects a precoding matrix and a rank for the SU MIMO transmission, based on the estimated raw covariance matrix and the selected allowed precoding matrix set. 
     According to a second aspect of embodiments herein, the object is achieved by a network node configured to handle a Single User, SU, Multiple Input Multiple Output, MIMO, transmission from a User Equipment, UE, in a wireless communications network. The network node is further configured to: 
     Select an allowed precoding matrix set for the SU MIMO transmission, 
     estimate a raw covariance matrix for the SU MIMO transmission, based on a Demodulation Reference Signal, DMRS, of a Physical Uplink Shared Channel, PUSCH, received from the UE  120 , and 
     select a precoding matrix and a rank for the SU MIMO transmission, based on the estimated raw covariance matrix and the selected allowed precoding matrix set. 
     SRS capacity and coverage limitation will not limit the uplink SU MIMO since the rank and precoding matrix selection are based on the DMRS of PUSCH. 
     The UE power consumption will be less than SRS solution since SRS is not needed. This results in that the performance of a wireless communications network using SU MIMO transmissions is improved. 
     Yet another advantage of embodiments herein is that for high speed case, more accurate rank and precoding matrix can be estimated based on DMRS, because DMRS is more fresh than SRS, thereby better performance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Examples of embodiments herein are described in more detail with reference to attached drawings in which: 
         FIG. 1  is a schematic block diagram illustrating embodiments of a wireless communications network. 
         FIG. 2  is a flowchart depicting embodiments of a method in a network node. 
         FIG. 3  is a schematic block diagram illustrating embodiments of a network node. 
         FIG. 4  is a schematic block diagram illustrating embodiments of a network node. 
         FIG. 5  schematically illustrates a telecommunication network connected via an intermediate network to a host computer. 
         FIG. 6  is a generalized block diagram of a host computer communicating via a base station with a user equipment over a partially wireless connection. 
         FIGS. 7 to 10  are flowcharts illustrating methods implemented in a communication system including a host computer, a base station and a user equipment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments herein are based on the insight that in both LTE and NR, SRS will be used in order to estimate or select the rank and PMI for uplink SU MIMO transmissions. However, both SRS capacity and coverage will be limitation for the system. 
     Embodiments herein relate to DMRS Based Uplink SU MIMO. 
     Examples of embodiments herein aims to decouple the uplink SU MIMO transmissions and SRS, in order to remove, for pure DRMS embodiments, or mitigate the dependency to SRS, for mixed SRS and DMRS embodiments. 
     In an example of the embodiments herein, the PUSCH DMRS is used to: 
     (1) Select allowed precoding matrix set for next transmission, (2) estimate the precoded covariance matrix to (3) estimate the raw covariance matrix, and then to (4) select rank for uplink SU MIMO and (5) select precoding matrix for uplink SU MIMO. 
     In this way the uplink SU MIMO is decoupled from SRS. This means that uplink SU MIMO can work without using any SRS resource. The SRS capacity and coverage limitation will in this way not limit the uplink SU MIMO because the rank and precoding matrix selection are based on the DMRS of PUSCH. Further, the UE power consumption will be less than SRS solution since SRS is not needed. 
     The use of mixed SRS and DMRS mode is not excluded. 
       FIG. 1  is a schematic overview depicting a wireless communications network  100  wherein embodiments herein may be implemented. The wireless communications network  100  comprises one or more RANs  104  and one or more CNs  106 . The wireless communications network  100  may use 5G NR but may further use a number of other different technologies, such as, Wi-Fi, (LTE), LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. 
     Network nodes operate in the wireless communications network  100 , such as a radio network node  110  providing radio coverage by means of antenna beams, referred to as beams herein. 
     The radio network node  110  provides radio coverage over a geographical area by means of antenna beams. The geographical area may be referred to as a cell, a service area, beam or a group of beams. The radio network node  110  may be a transmission and reception point e.g. a radio access network node such as a base station, e.g. a radio base station such as a NodeB, an evolved Node B (eNB, eNode B), an NR Node B (gNB), a base transceiver station, a radio remote unit, an Access Point Base Station, a base station router, a transmission arrangement of a radio base station, a stand-alone access point, a Wireless Local Area Network (WLAN) access point, an Access Point Station (AP STA), an access controller, a UE acting as an access point or a peer in a Device to Device (D2D) communication, or any other network unit capable of communicating with a UE within the cell served by the radio network node  110  depending e.g. on the radio access technology and terminology used. 
     UEs such as a UE  120  operate in the wireless communication network  100 . The UE  120  may e.g. be a mobile station, a non-access point (non-AP) STA, a STA, a user equipment and/or a wireless terminals, an NB-IoT device, an eMTC device and a CAT-M device, a WiFi device, an LTE device and an NR device communicate via one or more Access Networks (AN), e.g. RAN, to one or more core networks (CN). It should be understood by the skilled in the art that “UE” is a non-limiting term which means any terminal, wireless communication terminal, wireless device, Device to Device (D2D) terminal, or node e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or even a small base station communicating within a cell. 
     The methods according to embodiments herein are performed by the radio network node  110 . As an alternative, a Distributed Node (DN) and functionality, e.g. comprised in a cloud  130  as shown in  FIG. 1  may be used for performing or partly performing the methods. 
     Example embodiments of a method performed by a network node  110  for handling a SU MIMO, transmission from a UE  120  in the wireless communications network  100 , will now be described with reference to a flowchart depicted in  FIG. 2 . 
     The method comprises the following actions, which actions may be taken in any suitable order. Actions that are optional are presented in dashed boxes in  FIG. 2 . 
     Action  200   
     Each PUSCH transmission uses one selected precoding matrix, and typically the network node  110  will inform the UE  120  about the selected precoding matrix transmission by transmission. PUSCH is shared by all UEs in a cell and is used to transmit their data to the network node  110 . In some embodiments the network node  110  instructs the UE  120  to use a number of selected precoding matrices to transmit the same number of PUSCH transmissions comprising data and the DM RS. It is one transmission per selected precoding matrix. E.g., M precoding matrices for M transmissions, in a 1 to 1 mapping. This is to estimate the first valid raw covariance matrix after receiving several initial PUSCH transmissions. This may be referred to as initialization. 
     Action  201   
     The network node  110  selects  201  an allowed precoding matrix set for the SU MIMO transmission. An allowed precoding matrix set when used herein is a set of precoding matrices which are allowed to be used for next SU MIMO transmission. The “allowed” is corresponding to the selection criteria in section “Select allowed precoding matrix set” below, it is actually the approach itself. The wording “Select allowed precoding matrix set” may be referred to as to “Select precoding matrix set”. 
     Action  202   
     In some embodiments the network node  110  further estimates full rank precoding matrix over a number of Transmission Time Intervals (TTIs). A full rank precoding matrix when used herein is a square matrix which has full matrix rank and consists of one or several precoding matrices. It should be noted that the matrix rank herein is the mathematical concept, not same as the rank of a PUSCH transmission. 
     Action  203   
     In some embodiments the network node  110  estimates a precoded covariance matrix based on channel estimation according to the DMRS of the PUSCH received from the UE  120 . A precoded covariance matrix when used herein is a covariance matrix of the precoded channel matrix. 
     Action  204   
     The network node  110  then estimates a raw covariance matrix for the SU MIMO transmission. According to embodiments herein, the estimate is based on a DMRS of a PUSCH received from the UE  120 . A raw covariance matrix when used herein is a covariance matrix of the channel matrix without any precoding. 
     In some embodiments as mentioned above, the network node  110  has estimated in Action  202 , a full rank precoding matrix over a number of TTIs, and has estimated in Action  203 , a precoded covariance matrix based on channel estimation according to the DMRS of the PUSCH received from the UE  120 . In these embodiments, the estimation of the raw covariance matrix for the SU MIMO transmission based on the DMRS of the PUSCH received from the UE  120  comprises: Estimating  204  the raw covariance matrix for the SU MIMO transmission based on the estimated precoded covariance matrix and the estimated full rank precoding matrix. 
     When estimating precoded covariance matrix, the full rank precoding matrix may also be obtained at the same time. And full rank precoding matrix together with precoded covariance matrix will be used to estimate the raw covariance matrix. 
     Action  205  and  206   
     According to embodiments herein, network node  110  then selects a precoding matrix and a rank for the SU MIMO transmission, based on the estimated raw covariance matrix and the selected allowed precoding matrix set. A precoding matrix when used herein is a matrix used by a UE such as the UE  120  for the precoding of the uplink transmission A rank when used herein is a number of parallel data streams transmitted by the UE  120 . 
     This may be performed by: 
     Selecting in Action  205 , a precoding matrix for the SU MIMO transmission, is based on the estimated raw covariance matrix and selected allowed precoding matrix set, and 
     selecting in Action  206  the rank for the SU MIMO transmission, based on the selected precoding matrix for the SU MIMO transmission. 
     Action  207   
     The network node  110  sends to the UE  120 , the selected rank, and a precoding matrix indicator based on the selected precoding matrix for the SU MIMO transmission. 
     Embodiments herein such as mentioned above will now be further described and exemplified. The text below is applicable to and may be combined with any suitable embodiment described above. 
     The examples of the embodiments herein are mainly described in NR, but they applies to LTE as well. 
     For the examples below, assume that the number of the antenna of the network node  110  is M BS  and number of UE  120  antenna is M UE . The maximum number of rank or layer for uplink SU MIMO is N R ≥2, and note that N R ≤M UE ≤M Bs . 
     For codebook based SU MIMO, pre-defined codebooks are used as in 3GPP. The network node  110  estimates the rank and precoding matrix or PMI, then sends them to UE  120  via uplink grant. A codebook when used herein is a set of precoding matrices which can be used for SU MIMO precoding. 
     A maximum windows length in terms of number of PUSCH transmission is then defined by the network node  110 , such that it equals to M UE . 
     Initialization 
     As mentioned above, the network node  110  may in some embodiments instruct the UE  120  to use a number of selected precoding matrices to transmit the same number of PUSCH transmissions comprising data and the DMRS. This relates to Action  200  mentioned above. 
     To initiate a number of M PUSCH transmissions the network node  110  may trigger the initialization. The initialization is used to choose the M precoding matrices for the initial M PUSCH transmissions. The network node  110  will inform the UE  120  to use the selected M precoding matrices to transmit the M PUSCH transmissions which includes the data and DMRS. 
     The network node  110  chooses M precoding matrix V i , i ∈{0, M−1} from the codebook, with 1≤r i ≤M UE  layers, i ∈{0, M−1}, Σ i=0   M−1  r i =M UE  and: 
       rank( V )= M   UE    Equation (1)
 
     V with dimension M UE ×M UE  is the matrix which consists of the M matrix V i . 
     rank(⋅) is the matrix rank operation. It means V is a full rank matrix. 
     The M precoding V i  will be used for the M PUSCH transmissions for initialization. For each PUSCH transmission, the UE sends DMRS along with the data in the PUSCH. An example of embodiments will be explained below. 
     Select Allowed Precoding Matrix Set for Next Transmission 
     In this action, the network node  110  selects an allowed precoding matrix set for a next SU MIMO transmission. This relates to Action  201  mentioned above. 
     The network node  110  selects allowed precoding matrices for each rank r (from 1 to M UE ). The allowed precoding matrices for r depend on the rank of current transmission r t  and the evaluated rank r. If evaluated rank r is big enough, then retrospect is not needed, just use equation (2) below, otherwise precoding matrices information of previous TTIs are needed then use equation(3) below. 
     The selected precoding matrices for each rank r comprises the allowed precoding matrix set Φ. The precoding matrix and rank for next transmission will be selected in the set Φ. 
     E.g., assume the V t−k  and r t−k  are the precoding matrix and rank for PUSCH transmission of TTI t−k, and k ∈{0,1, . . . , M UE −1}. Note that k=0 is for the current slot t with the precoding matrix V t , and current rank or layer r t  corresponding to V t . Note that t−k is the TTI of the previous k th  PUSCH transmission, it may not the exact physical TTI number because PUSCH transmissions may not consecutive. 
     For rank r ∈[M UE −r t , M UE ], note the precoding V r  is chosen from the pre-defined codebooks with dimension M UE ×r. And the allowed precoding matrix V r  will satisfy: 
       rank([ V   t   , V   r ])= M   UE   Equation (2)
 
     For rank r∈[1, M UE −r t ), which means r+r t &lt;M UE . We find the minimum retrospective TTI number K r , which satisfies Σ k=0   K     r    r t−k ≥M UE −r, then the allowed precoding matrix V r  from the codebooks will satisfy: 
     
       
         
           
             
               
                 
                   
                     
                       
                         rank 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         
                           ( 
                           
                             [ 
                             
                               
                                 V 
                                 t 
                               
                               , 
                               
                                 V 
                                 r 
                               
                             
                             ] 
                           
                           ) 
                         
                       
                       = 
                       
                         r 
                         + 
                         
                           
                             Σ 
                             
                               k 
                               = 
                               0 
                             
                             0 
                           
                           ⁢ 
                           
                             r 
                             
                               t 
                               - 
                               k 
                             
                           
                         
                       
                     
                     ⁢ 
                     
                       
 
                     
                     ⁢ 
                     
                       rank 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       
                         ( 
                         
                           [ 
                           
                             
                               V 
                               
                                 t 
                                 - 
                                 1 
                               
                             
                             , 
                             
                               V 
                               t 
                             
                             , 
                             
                               V 
                               r 
                             
                           
                           ] 
                         
                         ) 
                       
                     
                     = 
                     
                       r 
                       + 
                       
                         
                           Σ 
                           
                             k 
                             = 
                             0 
                           
                           1 
                         
                         ⁢ 
                         
                           r 
                           
                             t 
                             - 
                             k 
                           
                         
                       
                     
                   
                   ⁢ 
                   
                     
 
                   
                   ⁢ 
                   … 
                   ⁢ 
                   
                     
 
                   
                   ⁢ 
                   
                     
                       rank 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       
                         ( 
                         
                           [ 
                           
                             
                               V 
                               
                                 t 
                                 - 
                                 
                                   K 
                                   r 
                                 
                               
                             
                             , 
                             … 
                             ⁢ 
                             
                                 
                             
                             , 
                             
                               V 
                               
                                 t 
                                 - 
                                 1 
                               
                             
                             , 
                             
                               V 
                               t 
                             
                             , 
                             
                               V 
                               t 
                             
                           
                           ] 
                         
                         ) 
                       
                     
                     = 
                     
                       r 
                       + 
                       
                         
                           Σ 
                           
                             k 
                             = 
                             0 
                           
                           
                             K 
                             τ 
                           
                         
                         ⁢ 
                         
                           r 
                           
                             t 
                             - 
                             k 
                           
                         
                       
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     ( 
                     3 
                     ) 
                   
                 
               
             
           
         
       
     
     Note V t =V t−0 , r t−0 =r t , and rank(⋅) is the matrix rank operation. 
     All the allowed V r  for specific rank r comprises the allowed precoding matrix set Φ, which will be used by the network node  110  to choose the best precoding matrix and rank for next transmission in the section Select rank and precoding matrix for uplink SU MIMO below. 
     Estimate the Precoded Covariance Matrix and Full Rank Precoding Matrix 
     In this action the network node estimates the precoded covariance matrix C, which is based on the channel estimation according to the DMRS of PUSCH. This relates to Actions  202  and  203  mentioned above. 
     According to the example, the network node  110  estimates and stores the channel matrices based on the DMRS of PUSCH. Then the network node  110  finds the minimum retrospective TTIs to get enough information, both channel matrix and precoding matrix, to construct a precoded covariance matrix C. A channel matrix when used herein means a matrix containing channel responses for all the antenna pairs, and each antenna pair means one UE antenna and one network node antenna. The network node  110  constructs block diagonal elements, and constructs other elements of C accordingly. Block diagonal elements when used herein means the square matrices on the diagonal of C. The network node  110  obtains the full rank precoding matrix V as well. 
     Note: the DMRS channel estimation method itself is not of interest in this document. 
     Without loss of generality, in the following description, the network node  110  assumes the granularity is per Resource Block (RB), however embodiments herein may apply to any other granularity. 
     The network node  110  assumes the estimated channel matrix over PUSCH transmission resource for each transmission of TTI t−k as H b     t−k   , b t−k  ∈ RB t−k , k ∈ {0,1, . . . , M UE −1}. Note that k=0 is for the current slot t with the estimated channel matrices H b     t   , b t  ∈ RB t , RB t  is the PUSCH RB set of current slot. 
     Note that above channel matrix H on different RB and different TTI is estimated from the PUSCH DMRS. 
     The network node  110  finds the minimum retrospective TTI number K, which satisfies Σ k=0   K  r t−k ≥M UE    
     The network node  110  gets the M UE ×M UE  matrix V by: 
         V ={ V   t   , V   t−1   , . . . , {circumflex over (V)}   t−k }={ v   0   , v   1   , . . . , v   M     UE     −1 },  K≤M   UE −1  Equation (4)
 
     Where {circumflex over (V)} t−k  is a subset of V t−K  which can satisfy rank(V)=M UE . 
     Then the network node  110  constructs the uplink precoded covariance matrix C as follows. 
     The network node  110  calculates the covariance C t , C t−1 , . . . , Ĉ t-K  as: 
     
       
         
           
             
               
                 
                   
                     C 
                     
                       t 
                       - 
                       k 
                     
                   
                   = 
                   
                     
                       1 
                       
                         N 
                         
                           t 
                           - 
                           k 
                         
                       
                     
                     ⁢ 
                     
                       Σ 
                       
                         
                           b 
                           
                             t 
                             - 
                             k 
                           
                         
                         ∈ 
                         
                           R 
                           ⁢ 
                           
                             B 
                             
                               t 
                               - 
                               k 
                             
                           
                         
                       
                     
                     ⁢ 
                     
                       H 
                       
                         b 
                         
                           t 
                           - 
                           k 
                         
                       
                       H 
                     
                     ⁢ 
                     
                       H 
                       
                         b 
                         
                           t 
                           - 
                           k 
                         
                       
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     ( 
                     5 
                     ) 
                   
                 
               
             
           
         
       
     
     Where N t−k  is the number of RB of PUSCH in TTI t−k. And Ĉ t−K  is the subset of C t−K  by choosing the corresponding precoding matrices. 
     Then the network node  110  fills C t , C t−1 , . . . , Ĉ t−k  into C block diagonally from C 0,0  to C M     UE     −1,M     UE     −1 . 
     For the other elements c i,j  in C, which means the corresponding precoding matrices v i  and v j  are in different TTIs, note as t−k i  and t−k j . Note the intersection of RB t−k     i    and RB t−k     j    is RB i,j . 
     If RB i,j  is not empty: 
     
       
         
           
             
               
                 
                   
                     c 
                     
                       i 
                       , 
                       j 
                     
                   
                   = 
                   
                     
                       1 
                       
                         N 
                         
                           i 
                           , 
                           j 
                         
                       
                     
                     ⁢ 
                     
                       Σ 
                       
                         
                           b 
                           
                             t 
                             - 
                             
                               k 
                               i 
                             
                           
                         
                         , 
                         
                           
                             b 
                             
                               t 
                               - 
                               
                                 k 
                                 j 
                               
                             
                           
                           ∈ 
                           
                             R 
                             ⁢ 
                             
                               B 
                               
                                 i 
                                 , 
                                 j 
                               
                             
                           
                         
                       
                     
                     ⁢ 
                     
                       h 
                       
                         b 
                         
                           t 
                           - 
                           
                             k 
                             i 
                           
                         
                       
                       H 
                     
                     ⁢ 
                     
                       h 
                       
                         b 
                         
                           t 
                           - 
                           
                             k 
                             j 
                           
                         
                       
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     ( 
                     6 
                     ) 
                   
                 
               
             
           
         
       
     
     Else, choose the nearest RB indexes in RB t−k     i    and RB t−k     j   , note as rb i  and rb j : 
         c   i,j   =Σh   rb     i     H   h   rb     j     Equation (7)
 
     Where h b     t−ki    and h rb     i    are the channel matrix corresponding to precoding matrix v i , h b     t−kj    and h rb     j    are the channel matrix corresponding to precoding matrix v j . 
     The network node  110  gets c j,i =c i,j   H  because is C Hermitian matrix. 
     Then the network node  110  gets the uplink precoded covariance matrix C with dimension M UE ×M UE . 
     Estimate the Raw Covariance Matrix 
     In this action, the network node  110  estimates, also referred to as recovers, the raw covariance matrix C UE  according to the precoded covariance matrix C and the full rank precoding matrix V in the section Estimate the precoded covariance matrix and full rank precoding matrix. This relates to Actions  204  mentioned above. The raw covariance matrix is the covariance matrix in terms of the raw channel matrix from the UE antennas to the network node  110  antennas, without any precoding. 
     The uplink raw covariance matrix C UE  essentially represents the spatial correlation of the UE&#39;s transmission antennas, it may be estimated as: 
         C   UE =( V   −1 ) H   CV   −1   Equation (8)
 
     Where V is the full rank precoding matrix and C is the precoded covariance matrix in mentioned above. 
     The matrix C UE  is used to choose the best precoding matrix and rank for next transmissions. 
     Select Rank and Precoding Matrix for Uplink SU MIMO 
     In this action the network node  110  selects the rank and the precoding matrix for uplink SU MIMO for next transmission. This relates to Actions  205  and  206  mentioned above. The network node  110  evaluates every precoding matrix in the precoding matrix set Φ, and then chooses the precoding matrix which has the highest capacity. During the evaluation, the raw covariance matrix C UE  is used together with each precoding matrix. Once the precoding matrix is selected, the rank is also selected because the selected precoding matrix is mapped to a specific rank. 
     Note that the rank and precoding matrix are selected by the raw covariance matrix C UE  and the precoding matrix set Φ. 
     According to C UE  and precoding matrix set Φ in previous sections, it is possible for the network node  110  to get the best precoding matrix and corresponding rank as: 
         V   best =arg max v     i     ∈Φ [capacity( V   i   H    C   UE   V   i )]  Equation (9)
 
     Where Φ is the total precoding matrix set including all possible ranks, and capacity(⋅) is the channel capacity metric in terms of different criterions. 
     Note that the function of capacity(⋅) in (9) is not novel, many criterions can be utilized. 
     Implementation Example 
     In this example it is assumed that the UE  120  has 2 transmission antennas with max uplink rank 2. The precoding matrix from 3GPP are given as follows: 
     Rank 1: 
     
       
         
           
               
               
             
               
                   
               
               
                   
                 Precoding matrix V i   
               
               
                 TPMI 
                 ordered from left to right in increasing order of TPMI index 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 0-5 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 1 
                               
                             
                             
                               
                                 0 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 0 
                               
                             
                             
                               
                                 1 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 1 
                               
                             
                             
                               
                                 1 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 1 
                               
                             
                             
                               
                                 
                                   - 
                                   1 
                                 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 1 
                               
                             
                             
                               
                                 j 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 1 
                               
                             
                             
                               
                                 
                                   - 
                                   j 
                                 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     Rank 2, TPMI Uses 6-8 to be Distinguished with Rank 1 Table: 
     
       
         
           
               
               
             
               
                   
               
               
                   
                 Precoding matrix V i   
               
               
                 TPMI 
                 ordered from left to right in increasing order of TPMI index 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 6-8 
                 
                   
                     
                       
                         
                           1 
                           
                             2 
                           
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 1 
                               
                               
                                 0 
                               
                             
                             
                               
                                 0 
                               
                               
                                 1 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 1 
                               
                               
                                 1 
                               
                             
                             
                               
                                 1 
                               
                               
                                 
                                   - 
                                   1 
                                 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
                 
                   
                     
                       
                         
                           1 
                           2 
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 1 
                               
                               
                                 1 
                               
                             
                             
                               
                                 j 
                               
                               
                                 
                                   - 
                                   j 
                                 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     For initialization, the network node  110  chooses V 0  and V 1  for 2 PUSCH transmissions. 
     For current TTI t, it is assumed that current rank is 1 and current precoding matrix is 
     
       
         
           
             
               V 
               3 
             
             = 
             
               
                 
                   1 
                   
                     2 
                   
                 
                 ⁡ 
                 
                   [ 
                   
                     
                       
                         1 
                       
                     
                     
                       
                         
                           - 
                           1 
                         
                       
                     
                   
                   ] 
                 
               
               . 
             
           
         
       
     
     And for TTI t−1, the rank is 1 and precoding matrix is 
     
       
         
           
             
               V 
               2 
             
             = 
             
               
                 
                   1 
                   
                     2 
                   
                 
                 ⁡ 
                 
                   [ 
                   
                     
                       
                         1 
                       
                     
                     
                       
                         1 
                       
                     
                   
                   ] 
                 
               
               . 
             
           
         
       
     
     For simplification, it is assumed that same RB sets are used for t and t−1, note as RB t , and N t  is the number of used RB. Note that algorithm above covers other cases. 
     The network node  110  selects the precoding matrix set for next transmission: 
     For rank r=1 and r=2, we choose the precoding matrix to satisfy: 
       rank([ V   3   , V   r ])=2  Equation (10)
 
     So for r=1, V 0 , V 1 , V 2 , V 4 , V 5  are allowed for next transmission. For r=2, V 6 , V 7 , V 8  are allowed for next transmission. 
     Then the precoding matrix set Φ={V 0 , V 1 , V 2 , V 4 , V 5 , V 6 , V 7 , V 8 } 
     The network node  110  finds minimum retrospective TTI number K=1, and gets the 2×2 matrix 
     
       
         
           
             V 
             = 
             
               
                 { 
                 
                   
                     V 
                     3 
                   
                   , 
                   
                     V 
                     2 
                   
                 
                 } 
               
               = 
               
                 
                   
                     1 
                     
                       2 
                     
                   
                   ⁡ 
                   
                     [ 
                     
                       
                         
                           1 
                         
                         
                           1 
                         
                       
                       
                         
                           
                             - 
                             1 
                           
                         
                         
                           1 
                         
                       
                     
                     ] 
                   
                 
                 . 
               
             
           
         
       
     
     The network node  110  gets the 2×2 uplink precoded covariance matrix C as follows, note that it is assumed both TTI t and t−1 use RB t  for simplification: 
     
       
         
           
             
               
                 
                   
                     
                       c 
                       
                         0 
                         , 
                         0 
                       
                     
                     = 
                     
                       
                         1 
                         
                           N 
                           t 
                         
                       
                       ⁢ 
                       
                         
                           ∑ 
                           
                             
                               b 
                               t 
                             
                             ∈ 
                             
                               RB 
                               t 
                             
                           
                         
                         ⁢ 
                         
                           
                             H 
                             
                               b 
                               t 
                             
                             H 
                           
                           ⁢ 
                           
                             H 
                             
                               b 
                               t 
                             
                           
                         
                       
                     
                   
                   ⁢ 
                   
                     
 
                   
                   ⁢ 
                   
                     
                       c 
                       
                         1 
                         , 
                         1 
                       
                     
                     = 
                     
                       
                         1 
                         
                           N 
                           t 
                         
                       
                       ⁢ 
                       
                         
                           ∑ 
                           
                             
                               b 
                               t 
                             
                             ∈ 
                             
                               RB 
                               t 
                             
                           
                         
                         ⁢ 
                         
                           
                             H 
                             
                               b 
                               
                                 t 
                                 - 
                                 1 
                               
                             
                             H 
                           
                           ⁢ 
                           
                             H 
                             
                               b 
                               
                                 t 
                                 - 
                                 1 
                               
                             
                           
                         
                       
                     
                   
                   ⁢ 
                   
                     
 
                   
                   ⁢ 
                   
                     
                       c 
                       
                         0 
                         , 
                         1 
                       
                     
                     = 
                     
                       
                         1 
                         
                           N 
                           t 
                         
                       
                       ⁢ 
                       
                         
                           ∑ 
                           
                             
                               b 
                               t 
                             
                             ∈ 
                             
                               RB 
                               t 
                             
                           
                         
                         ⁢ 
                         
                           
                             H 
                             
                               b 
                               t 
                             
                             H 
                           
                           ⁢ 
                           
                             H 
                             
                               b 
                               
                                 t 
                                 - 
                                 1 
                               
                             
                           
                         
                       
                     
                   
                   ⁢ 
                   
                     
 
                   
                   ⁢ 
                   
                     
                       c 
                       
                         1 
                         , 
                         0 
                       
                     
                     = 
                     
                       c 
                       
                         0 
                         , 
                         1 
                       
                       H 
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   
                     ( 
                     11 
                     ) 
                   
                 
               
             
           
         
       
     
     The network node  110  gets 2×2 uplink raw covariance matrix 
     
       
         
           
             
               C 
               UE 
             
             = 
             
               
                 
                   
                     ( 
                     
                       V 
                       
                         - 
                         1 
                       
                     
                     ) 
                   
                   H 
                 
                 ⁢ 
                 C 
                 ⁢ 
                 
                   V 
                   
                     - 
                     1 
                   
                 
               
               = 
               
                 
                   
                     1 
                     2 
                   
                   ⁡ 
                   
                     [ 
                     
                       
                         
                           1 
                         
                         
                           1 
                         
                       
                       
                         
                           
                             - 
                             1 
                           
                         
                         
                           1 
                         
                       
                     
                     ] 
                   
                 
                 ⁢ 
                 
                   
                     C 
                     ⁡ 
                     
                       [ 
                       
                         
                           
                             1 
                           
                           
                             
                               - 
                               1 
                             
                           
                         
                         
                           
                             1 
                           
                           
                             1 
                           
                         
                       
                       ] 
                     
                   
                   . 
                 
               
             
           
         
       
     
     Then the network node  110  may use C UE  and Φ to choose the rank and precoding matrix for next transmission based on the section Select rank and precoding matrix for uplink SU MIMO above or any other criterion. 
     To perform the method actions above for handle an SU MIMO transmission from the UE  120  in the wireless communications network  100 , the network node  110  may comprise the arrangement depicted in  FIG. 3  and  FIG. 4 . 
     The network node  110  may comprise an input and output interface  400  depicted in  FIG. 3 , configured to communicate e.g. with the UE  120 . The input and output interface  1100  may comprise a wireless receiver (not shown) and a wireless transmitter (not shown). 
     The network node  110  is configured to, e.g. by means of a selecting unit  410  in the network node  110  depicted in  FIG. 4 , select an allowed precoding matrix set for the SU MIMO transmission. 
     The network node  110  is further configured to, e.g. by means of an estimating unit  420  in the network node  110  depicted in  FIG. 4 , estimate a raw covariance matrix for the SU MIMO transmission, based on a DMRS of a PUSCH received from the UE  120 . 
     The network node  110  is further configured to, e.g. by means of an selecting unit  430  in the network node  110  depicted in  FIG. 4 , select a precoding matrix and a rank for the SU MIMO transmission, based on the estimated raw covariance matrix and the selected allowed precoding matrix set. 
     In some embodiments, the network node  110  is further configured to, e.g. by means of the estimating unit  420  in the network node  110 , estimate full rank precoding matrix over a number of TTIs and estimate a precoded covariance matrix based on channel estimation according to the DMRS of the PUSCH received from the UE  120 . In these embodiments, the network node  110  may further be configured to, e.g. by means of the estimating unit  420  in the network node  110 , estimate the raw covariance matrix for the SU MIMO transmission, based on the DMRS of the PUSCH received from the UE  120  by estimating the raw covariance matrix for the SU MIMO transmission based on the estimated precoded covariance matrix and the estimated full rank precoding matrix. 
     In some embodiments, the network node  110  is further configured to e.g. by means of the selecting unit  430  in the network node  110 , select the precoding matrix and the rank for the SU MIMO transmission, based on the estimated raw covariance matrix and the selected allowed precoding matrix set by: Selecting a precoding matrix for the SU MIMO transmission, is based on the estimated raw covariance matrix and selected allowed precoding matrix set, and selecting the rank for the SU MIMO transmission, is based on the selected  205  a precoding matrix for the SU MIMO transmission. 
     In some embodiments, the network node  110  is further configured to e.g. by means of a sending unit  440  in the network node  110  depicted in  FIG. 4 , send to the UE  120 , the selected rank and a precoding matrix indicator based on the selected precoding matrix for the SU MIMO transmission. 
     In some embodiments, the network node  110  is further configured to e.g. by means of a instructing unit  450  in the network node  110  depicted in  FIG. 4 , instruct to the UE  120  to use a number of selected precoding matrices to transmit the same number of PUSCH transmissions comprising data and the DMRS. 
     The embodiments herein may be implemented through a respective processor or one or more processors, such as a processor  460  of a processing circuitry in the network node  110  depicted in  FIG. 3 , together with a respective computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the network node  110 . One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the network node  110 . 
     The network node  110  may further comprise a memory  470  comprising one or more memory units to store data on. The memory comprises instructions executable by the processor  460 . The memory  470  is arranged to be used to store e.g. allowed precoding matrix set, precoded covariance matrix, raw covariance matrix, precoded covariance matrix raw covariance matrix, rank, precoding matrix data, configurations and applications to perform the methods herein when being executed in the network node  110 . 
     Those skilled in the art will also appreciate that the units in the radio network node  110  mentioned above may refer to a combination of analogue and digital circuits, and/or one or more processors configured with software and/or firmware, e.g. stored in the network node  110  that when executed by the respective one or more processors such as the processors described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuitry (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a system-on-a-chip (SoC). 
     In some embodiments, a computer program  480  comprises instructions, which when executed by the respective at least one processor  460 , cause the at least one processor  460  of the network node  110  to perform the actions above. 
     In some embodiments, a carrier  490  comprises the computer program  480 , wherein the carrier  490  is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium. 
     Further Extensions and Variations 
     With reference to  FIG. 5 , in accordance with an embodiment, a communication system includes a telecommunication network  3210  such as the wireless communications network  100 , e.g. a NR network, such as a 3GPP-type cellular network, which comprises an access network  3211 , such as a radio access network, and a core network  3214 . The access network  3211  comprises a plurality of base stations  3212   a,    3212   b,    3212   c,  such as the radio network node  110 , access nodes, AP STAs NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area  3213   a,    3213   b ,  3213   c.  Each base station  3212   a,    3212   b,    3212   c  is connectable to the core network  3214  over a wired or wireless connection  3215 . A first user equipment (UE) e.g. the wireless devices  120  such as a Non-AP STA  3291  located in coverage area  3213   c  is configured to wirelessly connect to, or be paged by, the corresponding base station  3212   c.  A second UE  3292  e.g. the first or second radio node  110 ,  120  or such as a Non-AP STA in coverage area  3213   a  is wirelessly connectable to the corresponding base station  3212   a . While a plurality of UEs  3291 ,  3292  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  3212 . 
     The telecommunication network  3210  is itself connected to a host computer  3230 , 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. The host computer  3230  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. The connections  3221 ,  3222  between the telecommunication network  3210  and the host computer  3230  may extend directly from the core network  3214  to the host computer  3230  or may go via an optional intermediate network  3220 . The intermediate network  3220  may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network  3220 , if any, may be a backbone network or the Internet; in particular, the intermediate network  3220  may comprise two or more sub-networks (not shown). 
     The communication system of  FIG. 5  as a whole enables connectivity between one of the connected UEs  3291 ,  3292  and the host computer  3230 . The connectivity may be described as an over-the-top (OTT) connection  3250 . The host computer  3230  and the connected UEs  3291 ,  3292  are configured to communicate data and/or signaling via the OTT connection  3250 , using the access network  3211 , the core network  3214 , any intermediate network  3220  and possible further infrastructure (not shown) as intermediaries. The OTT connection  3250  may be transparent in the sense that the participating communication devices through which the OTT connection  3250  passes are unaware of routing of uplink and downlink communications. For example, a base station  3212  may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer  3230  to be forwarded (e.g., handed over) to a connected UE  3291 . Similarly, the base station  3212  need not be aware of the future routing of an outgoing uplink communication originating from the UE  3291  towards the host computer  3230 . 
     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. 6 . In a communication system  3300 , a host computer  3310  comprises hardware  3315  including a communication interface  3316  configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system  3300 . The host computer  3310  further comprises processing circuitry  3318 , which may have storage and/or processing capabilities. In particular, the processing circuitry  3318  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. The host computer  3310  further comprises software  3311 , which is stored in or accessible by the host computer  3310  and executable by the processing circuitry  3318 . The software  3311  includes a host application  3312 . The host application  3312  may be operable to provide a service to a remote user, such as a UE  3330  connecting via an OTT connection  3350  terminating at the UE  3330  and the host computer  3310 . In providing the service to the remote user, the host application  3312  may provide user data which is transmitted using the OTT connection  3350 . 
     The communication system  3300  further includes a base station  3320  provided in a telecommunication system and comprising hardware  3325  enabling it to communicate with the host computer  3310  and with the UE  3330 . The hardware  3325  may include a communication interface  3326  for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system  3300 , as well as a radio interface  3327  for setting up and maintaining at least a wireless connection  3370  with a UE  3330  located in a coverage area (not shown in  FIG. 6 ) served by the base station  3320 . The communication interface  3326  may be configured to facilitate a connection  3360  to the host computer  3310 . The connection  3360  may be direct or it may pass through a core network (not shown in  FIG. 6 ) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware  3325  of the base station  3320  further includes processing circuitry  3328 , 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. The base station  3320  further has software  3321  stored internally or accessible via an external connection. 
     The communication system  3300  further includes the UE  3330  already referred to. Its hardware  3335  may include a radio interface  3337  configured to set up and maintain a wireless connection  3370  with a base station serving a coverage area in which the UE  3330  is currently located. The hardware  3335  of the UE  3330  further includes processing  35  circuitry  3338 , 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. The UE  3330  further comprises software  3331 , which is stored in or accessible by the UE  3330  and executable by the processing circuitry  3338 . The software  3331  includes a client application  3332 . The client application  3332  may be operable to provide a service to a human or non-human user via the UE  3330 , with the support of the host computer  3310 . In the host computer  3310 , an executing host application  3312  may communicate with the executing client application  3332  via the OTT connection  3350  terminating at the UE  3330  and the host computer  3310 . In providing the service to the user, the client application  3332  may receive request data from the host application  3312  and provide user data in response to the request data. The OTT connection  3350  may transfer both the request data and the user data. The client application  3332  may interact with the user to generate the user data that it provides. 
     It is noted that the host computer  3310 , base station  3320  and UE  3330  illustrated in  FIG. 6  may be identical to the host computer  3230 , one of the base stations  3212   a ,  3212   b,    3212   c  and one of the UEs  3291 ,  3292  of  FIG. 5 , respectively. This is to say, the inner workings of these entities may be as shown in  FIG. 6  and independently, the surrounding network topology may be that of  FIG. 5 . 
     In  FIG. 6 , the OTT connection  3350  has been drawn abstractly to illustrate the communication between the host computer  3310  and the use equipment  3330  via the base station  3320 , 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 the UE  3330  or from the service provider operating the host computer  3310 , or both. While the OTT connection  3350  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). 
     The wireless connection  3370  between the UE  3330  and the base station  3320  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 the UE  3330  using the OTT connection  3350 , in which the wireless connection  3370  forms the last segment. More precisely, the teachings of these embodiments may improve the data rate, latency, power consumption and thereby provide benefits such as user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime. 
     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 the OTT connection  3350  between the host computer  3310  and UE  3330 , in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection  3350  may be implemented in the software  3311  of the host computer  3310  or in the software  3331  of the UE  3330 , or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection  3350  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  3311 ,  3331  may compute or estimate the monitored quantities. The reconfiguring of the OTT connection  3350  may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station  3320 , and it may be unknown or imperceptible to the base station  3320 . Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer&#39;s  3310  measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software  3311 ,  3331  causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection  3350  while it monitors propagation times, errors etc. 
       FIG. 7  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 such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to  FIG. 5  and  FIG. 6 . For simplicity of the present disclosure, only drawing references to  FIG. 7  will be included in this section. In a first action  3410  of the method, the host computer provides user data. In an optional subaction  3411  of the first action  3410 , the host computer provides the user data by executing a host application. In a second action  3420 , the host computer initiates a transmission carrying the user data to the UE. In an optional third action  3430 , 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 an optional fourth action  3440 , the UE executes a client application associated with the host application executed by the host computer. 
       FIG. 8  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 such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to  FIG. 5  and  FIG. 6 . For simplicity of the present disclosure, only drawing references to  FIG. 8  will be included in this section. In a first action  3510  of the method, the host computer provides user data. In an optional subaction (not shown) the host computer provides the user data by executing a host application. In a second action  3520 , 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 an optional third action  3530 , the UE receives the user data carried in the transmission. 
       FIG. 9  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 such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to  FIG. 5  and  FIG. 6 . For simplicity of the present disclosure, only drawing references to  FIG. 9  will be included in this section. In an optional first action  3610  of the method, the UE receives input data provided by the host computer. Additionally or alternatively, in an optional second action  3620 , the UE provides user data. In an optional subaction  3621  of the second action  3620 , the UE provides the user data by executing a client application. In a further optional subaction  3611  of the first action  3610 , 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 an optional third subaction  3630 , transmission of the user data to the host computer. In a fourth action  3640  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. 10  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 such as an AP STA, and a UE such as a Non-AP STA which may be those described with reference to  FIG. 5  and  FIG. 6 . For simplicity of the present disclosure, only drawing references to  FIG. 10  will be included in this section. In an optional first action  3710  of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In an optional second action  3720 , the base station initiates transmission of the received user data to the host computer. In a third action  3730 , the host computer receives the user data carried in the transmission initiated by the base station. 
     When using the word “comprise” or “comprising” it shall be interpreted as non-limiting, i.e. meaning “consist at least of”. 
     The embodiments herein are not limited to the above described preferred embodiments. Various alternatives, modifications and equivalents may be used.