Patent Publication Number: US-10778394-B2

Title: Joint transmission of precoded and unprecoded sounding reference signals in uplink

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a Divisional Application of U.S. Non-Provisional application Ser. No. 15/689,476 filed Aug. 29, 2017, which claims priority to and the benefit of the U.S. Provisional Patent Application No. 62/402,141, filed Sep. 30, 2016, each of which is hereby incorporated by reference in its entirety as if fully set forth below in its entirety and for all applicable purposes. 
    
    
     TECHNICAL FIELD 
     Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to transmitting both precoded sounding reference signals and unprecoded sounding reference signals from a user equipment, where the eNodeB may use some combination of both in scheduling resources. 
     INTRODUCTION 
     In wireless communication networks, sounding reference signals are transmitted in the uplink (UL) for use by base stations or eNodeBs (eNB) for a variety of aspects. Some of these include, for example, downlink scheduling, uplink scheduling (e.g., resource block allocation, rank assignment, modulation and coding scheme, etc.), and coordinated multipoint processing to name a few examples. 
     In current approaches, sounding reference signals (SRS) are unprecoded, meaning that the transmitting user equipment (UE) has not used beam steering to manipulate the antennas in a multiple input/multiple output (MIMO) system with particular weights to influence the radiation pattern from the UE. Further, precoded SRS are not envisioned as being used with unprecoded SRS. This results in reduced UL performance given the lack of either aspect of information when only the other is used. 
     As a result, there is a need for techniques to allow providing both SRS types so as to improve UL efficiency with increased flexibility at the eNB. 
     BRIEF SUMMARY OF SOME EXAMPLES 
     The following summarizes some aspects of the present disclosure to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in summary form as a prelude to the more detailed description that is presented later. 
     In one aspect of the disclosure, a method is provided that includes generating, by a first wireless communications device, a precoded sounding reference signal (SRS). The method further includes generating, by the first wireless communications device, an unprecoded SRS separate from the precoded SRS. The method further includes transmitting, by the first wireless communications device, the precoded SRS and the unprecoded SRS to a second wireless communications device via an uplink channel. 
     In an additional aspect of the disclosure, a method is provided that includes receiving, by a first wireless communications device, a precoded sounding reference signal (SRS) from a second wireless communications device. The method further includes receiving, by the first wireless communications device, an unprecoded SRS separate from the precoded SRS from the second wireless communications device. The method further includes determining, by the first wireless communications device, a resource scheduling for the second wireless communications device based on a combination of the precoded SRS and the unprecoded SRS. 
     In an additional aspect of the disclosure, an apparatus is provided that includes a processor configured to generate a precoded sounding reference signal (SRS). The processor is further configured to generate an unprecoded SRS separate from the precoded SRS. The apparatus further includes a transceiver configured to transmit the precoded SRS and the unprecoded SRS to a wireless communications device via an uplink channel. 
     In an additional aspect of the disclosure, an apparatus is provided that includes a transceiver configured to receive a precoded sounding reference signal (SRS) from a wireless communications device. The transceiver is further configured to receive an unprecoded SRS separate from the precoded SRS from the wireless communications device. The apparatus further includes a processor configured to determine a resource scheduling for the second wireless communications device based on a combination of the precoded SRS and the unprecoded SRS. 
     Other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain embodiments and figures below, all embodiments of the present invention can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the invention discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary wireless communication environment according to embodiments of the present disclosure. 
         FIG. 2  is a block diagram of an exemplary wireless communication device according to embodiments of the present disclosure. 
         FIG. 3  is a block diagram of an exemplary wireless communication device according to embodiments of the present disclosure. 
         FIG. 4  is a block diagram illustrating an exemplary transmitter and receiver system, such as eNodeB and user equipment, in accordance with various aspects of the present disclosure. 
         FIG. 5A  is a block diagram of an exemplary uplink frame structure according to embodiments of the present disclosure. 
         FIG. 5B  is a block diagram of an exemplary uplink control message structure according to embodiments of the present disclosure. 
         FIG. 5C  is a block diagram of an exemplary uplink control message structure according to embodiments of the present disclosure. 
         FIG. 6  is a flowchart illustrating an exemplary method for wireless communication in accordance with various aspects of the present disclosure. 
         FIG. 7  is a flowchart illustrating an exemplary method for wireless communication in accordance with various aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts. 
     The techniques described herein may be used for various wireless communication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, LTE networks, GSM networks, and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies, such as a next generation (e.g., 5th Generation (5G)) network. 
     Further, devices may also communicate with one another using various peer-to-peer technologies such as LTE-Direct (LTE-D), Bluetooth, Bluetooth Low Energy (BLE), ZigBee, radio frequency identification (RFID), and/or other ad-hoc or mesh network technologies. Embodiments of this disclosure are directed to any type of modulation scheme that may be used on any one or more of the above-recited networks and/or those yet to be developed. 
     Embodiments of the present disclosure introduce systems and techniques to transmit both precoded sounding reference signals and unprecoded sounding reference signals from a UE to an eNB, where the eNB may use some combination of both in scheduling resources for the UE. 
     For example, a UE may include both precoded SRS as well as unprecoded SRS in UL transmissions to an eNB (e.g., whether in periodic or aperiodic SRS uses). The precoding may involve weighting different antennas of a UE different amounts, so as to cause the UE to steer its radiation pattern, or beam, in a particular direction. The unprecoded SRS applies equal beam weights to each antenna of the UE. In some examples, the UE may make the determination of the specific precoding to apply to the SRS, such as based on DL reference signals from the eNB. In other examples, the UE may receive instruction from an eNB on a precoding to apply for an SRS. 
     The UE transmits the precoded SRS and the unprecoded SRS in the UL to the eNB. For example, the UE may use a time division multiplexing (TDM) approach, such that both precoded SRS and unprecoded SRS are included in a same subframe, each using the same tone or band of tones at different time slots (or symbol periods) in the same subframe. As another example, the UE may use a frequency division multiplexing approach, such that both the precoded SRS and unprecoded SRS are included in a same subframe, at the same time slot but using different tones (or subcarriers) with respect to each other. As another example, the UE may use different resource slots (time and/or frequency) in different subframes to transmit the precoded SRS and unprecoded SRS—thus, one of the SRS (e.g., precoded) may be transmitted in a first subframe followed, in a later subframe, by the other SRS (e.g., unprecoded, or vice versa). 
     The eNB receives both SRS types after transmission from the UE. With both precoded SRS and unprecoded SRS, the eNB has flexibility in use of these SRS in various functions, including PUSCH scheduling (e.g., RB allocation), UL rank assignments, UL MCS assignments, etc. For example, the eNB may determine to use the received precoded SRS for one aspect of scheduling/assignment and the received unprecoded SRS for another aspect of scheduling/assignment based on existing channel conditions. Any combination is possible in order to arrive at scheduling/assignment according to embodiments of the present disclosure. 
     In addition, the eNB may provide instruction to the UE for PUSCH precoding for data transmission. For example, after receiving both precoded SRS and unprecoded SRS from the UE, the eNB may determine that the UE will use the same precoding as was used for the precoded SRS. In that example, a single bit in a DL message may be used to signal the UE to use the same precoding for PUSCH data transmission. When the same precoding is not going to be used, then the eNB may not assert that bit. 
     In the bit is not asserted, the UE may further listen for additional signaling from the eNB identifying other precoding that the UE should use for transmitting data in the PUSCH. In some examples, the eNB may include the precoding data in full for use in PUSCH by the UE. A way to reduce signaling overhead is for the eNB to determine a delta between the precoding used for the precoded SRS and the precoding for the PUSCH that the eNB selects for the UE. The eNB may transmit that delta, instead of the full details of the precoding for the PUSCH, to the UE. This may provide more efficient use of resources as the signaling overhead may be reduced as compared to the option of transmitting the full amount of data. In turn, the UE receiving the delta information may recover the precoding for PUSCH by adding or multiplying the delta information with the precoding previously used for the SRS (whether addition or multiplication). 
       FIG. 1  illustrates a wireless communication network  100  in accordance with various aspects of the present disclosure. The wireless communication network  100  may include a number of UEs  102 , as well as a number of evolved Node Bs (eNodeB, or eNB)  104 . The eNBs  104  may also be referred to generally as base stations. An eNB  104  may also be referred to as an access point, base transceiver station, a node B, etc. An eNB  104  may be a station that communicates with the UEs  102 . 
     The eNBs  104  communicate with the UEs  102  as indicated by communication signals  106 . A UE  102  may communicate with the eNB  104  via an uplink and a downlink. The downlink (or forward link) refers to the communication link from the eNB  104  to the UE  102 . The uplink (or reverse link) refers to the communication link from the UE  102  to the eNB  104 . The eNBs  104  may also communicate with one another, directly or indirectly, over wired and/or wireless connections, as indicated by communication signals  108 . 
     UEs  102  may be dispersed throughout the wireless network  100 , as shown, and each UE  102  may be stationary or mobile. The UE  102  may also be referred to as a terminal, a mobile station, a subscriber unit, etc. The UE  102  may be a cellular phone, a smartphone, a personal digital assistant, a wireless modem, a laptop computer, a tablet computer, a drone, an entertainment device, a hub, a gateway, an appliance, a wearable, peer-to-peer and device-to-device components/devices (including fixed, stationary, and mobile), Internet of Things (IoT) components/devices, and Internet of Everything (IoE) components/devices, etc. The wireless communication network  100  is one example of a network to which various aspects of the disclosure apply. 
     Each eNB  104  may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to this particular geographic coverage area of an eNB and/or an eNB subsystem serving the coverage area, depending on the context in which the term is used. In this regard, an eNB  104  may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A pico cell would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). 
     An eNB for a macro cell may be referred to as a macro eNB. An eNB for a pico cell may be referred to as a pico eNB. And, an eNB for a femto cell may be referred to as a femto eNB or a home eNB. In the example shown in  FIG. 1 , the eNBs  104   a ,  104   b  and  104   c  are examples of macro eNB for the coverage areas  110   a ,  110   b  and  110   c , respectively (also referred to as cells herein). The eNBs  104   d  and  104   e  are examples of pico and/or femto eNBs for the coverage areas  110   d  and  110   e , respectively. An eNB  104  may support one or multiple (e.g., two, three, four, and the like) cells. 
     The wireless communication network  100  may also include relay stations. A relay station is a station that receives a transmission of data and/or other information from an upstream station (e.g., an eNB, a UE, or the like) and sends a transmission of the data and/or other information to a downstream station (e.g., another UE, another eNB, or the like). A relay station may also be a UE that relays transmissions for other UEs. A relay station may also be referred to as a relay eNB, a relay UE, a relay, and the like. Some relays may also have UE capabilities/functionalities. 
     The wireless communication network  100  may support synchronous or asynchronous operation. For synchronous operation, the eNBs  104  may have similar frame timing, and transmissions from different eNBs  104  may be approximately aligned in time. For asynchronous operation, the eNBs  104  may have different frame timing, and transmissions from different eNBs  104  may not be aligned in time. 
     In some implementations, the wireless communication network  100  utilizes orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, or the like. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, K may be equal to 72, 180, 300, 600, 900, and 1200 for a corresponding system bandwidth of 1.4, 3, 5, 10, 15, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into sub-bands. For example, a sub-band may cover 1.08 MHz, and there may be 1, 2, 4, 8 or 16 sub-bands for a corresponding system bandwidth of 1.4, 3, 5, 10, 15, or 20 MHz, respectively. 
     According to embodiments of the present disclosure, the UEs  102  may include both precoded SRS as well as unprecoded SRS in UL transmissions to eNBs  104  (e.g., whether in periodic or aperiodic SRS uses). The precoding may involve weighting different antennas of a UE  102  different amounts, so as to cause the UE  102  (an exemplary UE  102  in  FIG. 1 ) to steer its radiation pattern, or beam, in a particular (e.g., desired) direction. Additionally, the SRS precoding granularity may be wideband (same precoder applied across all tones) or narrow band (up to per tone precoding). The unprecoded SRS refers to a SRS in which equal beam weights are applied to each antenna of a UE  102 , so that no beam steering occurs outside of the regular configuration of the antennas. 
     In some examples, the UE  102  may make the determination of the specific precoding. For example, the UE  102  may receive one or more downlink (DL) reference signals, such as CSI-RS (channel state information-reference signals), from an eNB  104  and, according to the channel quality of the DL channel determined from the reference signals, identify a direction that is desirable in which to steer a beam of the UE  102 . In other examples, the UE  102  may receive instruction from an eNB  104  on a precoding to apply for an SRS (e.g., based on a measure of UL channel quality made at the eNB  104  with respect to one or more signals from the UE  102  and/or estimated from any other UE  102 &#39;s signals). 
     The UE  102  may transmit the precoded SRS and the unprecoded SRS in the UL in a variety of ways. For example, the UE  102  may use a time division multiplexing approach, such that both precoded SRS and unprecoded SRS are included in a same subframe, each using the same tone or band of tones at different time slots in the same subframe. Alternatively, the UE  102  may use a frequency division multiplexing approach, such that both the precoded SRS and unprecoded SRS are again included in a same subframe, though with this approach each uses the same time slot but different tones from among the available/selected frequency band with respect to each other. As another alternative, the UE  102  may use different resource slots (time and/or frequency) in different subframes to transmit the precoded SRS and unprecoded SRS—thus, one of the SRS (e.g., precoded) may be transmitted in a first subframe followed, in a later subframe, by the other SRS (e.g., unprecoded, or vice versa). In some embodiments, the subframes may be contiguous to each other in time, while in other embodiments the subframes may have one or more other subframes in between. Further, under any of the above-noted alternatives, each SRS is not limited as to which symbols in a given subframe they are to be located. 
     Whatever the approach taken in transmitting both of the precoded SRS and the unprecoded SRS, the eNB  104  receives both SRS types. With both precoded SRS and unprecoded SRS, the eNB  104  has flexibility in use of these SRS in various functions, including PUSCH scheduling (e.g., RB allocation), UL rank assignments, UL MCS assignments, etc. For example, the eNB  104  may determine to use the received precoded SRS for one aspect of scheduling/assignment and the received unprecoded SRS for another aspect of scheduling/assignment based on existing channel conditions—e.g., unprecoded SRS for RB allocation, precoded SRS for rank assignment, and both for MCS scheduling. This is just one example. Any combination is possible in order to arrive at scheduling/assignment according to embodiments of the present disclosure. For example, an SRS may be used for several purposes, including sounding the UL channel for UL PUSCH scheduling at the eNB  104  and (where there is DL/UL channel symmetricity, or it is at least assumed) for DL PDSCH scheduling. 
     Looking first at UL PUSCH scheduling, in embodiments the precoded SRS may be used. Where the UE  102  has multiple transmit ports, an eNB  104  may configure the UE  102  to sound multiple SRS (e.g., over different symbols as an example), each SRS with a different precoder. Then, the eNB  104  may measure the differently precoded SRS over different symbols and select the best precoder (i.e., the precoded SRS with the best measured characteristic from among the precoded SRSs measured). With the precoder selected, the eNB  104  may signal the UE  102  to use that selected precoder for UL PUSCH transmission. 
     Looking then at DL PDSCH scheduling, an unprecoded SRS may be used in embodiments. For example, the eNB  104  may seek to learn about the channel to determine what the best precoder may be for DL PDSCH transmission (e.g., to maximize throughput). In order to make this determination, the eNB  104  may first determine properties of the raw channel (i.e., unprecoded channel) for DL. After this, the eNB  104  may apply singular vector decomponsition (SVD) or another approach, based on the determined properties of the raw channel, to determine the best precoder for DL PDSCH transmission. 
     Accordingly, the UE  102  may transmit an unprecoded SRS, which the eNB  104  measures and from which the eNB  104  obtains the raw channel properties. The eNB  104  may assume that the DL raw channel is symmetric to the UL raw channel (e.g., with just a scalar difference due to UL/DL transmit power imbalance), which assumption for example typically holds for a time division duplex system. Because of the assumption by the eNB  104  in such embodiments that the learned UL raw channel is the same as the DL raw channel with perhaps a scalar difference, the eNB  104  may determine a precoder for DL PDSCH transmission based on the raw UL channel. 
     Further, the precoded SRS may be used for DL PDSCH scheduling. This relates to whether the eNB  104  has knowledge of the UE  102 &#39;s measured covariance matrix of interference plus noise. The unprecoded SRS may be used by the eNB  104  for DL PDSCH scheduling if the UE  102  feeds back to the eNB  104  the measured interference plus noise covariance matrix. For example, where the UE  102  feeds back the measured interference plus noise covariance matrix, the eNB  104  may use the unprecoded SRS to determine the raw channel, calculate the whitening matrix based on that measured interference plus noise, and determine the precoder for DL PDSCH transmission as discussed above. 
     If, however, the UE  102  does not feed back the measured covariance matrix of interference plus noise, then the eNB  104  may use the precoded SRS. For example, the UE  102  may set the precoder for the SRS to be the same as the whitening matrix (e.g., the interference plus noise measured at the UE  102 ) for the UE  102 . The UE  102  may use the precoded SRS to deliver the whitened channel information to the eNB  104 . Upon reaching the eNB  104 , the eNB  104  has information about the whitened channel based on the precoded SRS. The eNB  104  may apply SVD on the whitened channel information to determine a precoder for DL PDSCH transmission. Thus, if the whitening is done by the eNB  104 , then the unprecoded SRS may be used to determine a precoder for DL PDSCH transmission, while if whitening is done at the UE  102 , then the precoded SRS may be used to determine a precoder for DL PDSCH transmission. 
     In addition to determining how to use the received precoded SRS and unprecoded SRS, an eNB  104  may provide instruction to UEs  102  for PUSCH precoding for data transmission. For example, after receiving both precoded SRS and unprecoded SRS from an UE  102 , an eNB  104  may determine that the UE  102  will use the same precoding as was used for the SRS. In that example, a single bit in a DL message (e.g., in the DL control channel) may be used to signal the UE  102  (e.g., the bit asserted) to use the same precoding for PUSCH data transmission. When the same precoding is not going to be used, then the eNB  104  may not assert that bit, which the UE  102  will interpret accordingly. 
     In that situation, the UE  102  may further listen for further signaling from the eNB  104  identifying other precoding that the UE  102  should use for transmitting data in the PUSCH. In some examples, the eNB  104  may include the precoding data for use in PUSCH by the UE  102 . This may consume signaling overhead to an undesirable extent. To reduce that signaling overhead, the eNB  104  may determine a delta between the precoding used for the SRS from the UE  102  and the precoding for the PUSCH that the eNB  104  selects for the UE  102 . The eNB  104  may transmit that delta, instead of the full details of the precoding for the PUSCH, to the UE  102 . This may provide more efficient use of resources as the signaling overhead may be reduced as compared to the other option. In turn, the UE  102  receiving the delta information may recover the precoding for PUSCH by adding or multiplying the delta information with the precoding previously used for the SRS (whether addition or multiplication is used may be configured previously between the eNB  104  and UE  102 , such as at device initialization or other time). Further, the eNB  104  may signal, during operation, the UE  102  to transition to one or the other (addition or multiplication). 
       FIG. 2  is a block diagram of an exemplary wireless communication device  200  according to embodiments of the present disclosure. The wireless communication device  200  may be a UE having any one of many configurations described above. For purposes of example, wireless communication device  200  may be a UE  102  as discussed above with respect to  FIG. 1 . The UE  102  may include a processor  202 , a memory  204 , an SRS module  208 , a transceiver  210  (including a modem  212  and RF unit  214 ), and an antenna  216 . These elements may be in direct or indirect communication with each other, for example via one or more buses. 
     The processor  202  may have various features as a specific-type processor. For example, these may include a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein with reference to the UEs  102  introduced in  FIG. 1  above. The processor  202  may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The memory  204  may include a cache memory (e.g., a cache memory of the processor  302 ), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some embodiments, the memory  204  may include a non-transitory computer-readable medium. The memory  204  may store instructions  206 . The instructions  206  may include instructions that, when executed by the processor  202 , cause the processor  202  to perform operations described herein with reference to a UE  102  in connection with embodiments of the present disclosure. The terms “instructions” and “code” may include any type of computer-readable statement(s). For example, the terms “instructions” and “code” may refer to one or more programs, routines, sub-routines, functions, procedures, etc. “Instructions” and “code” may include a single computer-readable statement or many computer-readable statements. 
     The SRS module  208  may be used for various aspects of the present disclosure. The SRS module  208  may include various hardware components and/or software components to assist in determining what particular precoding to use for the precoded SRS, as well as how to transmit both the precoded SRS and the unprecoded SRS (e.g., using TDM, FDM, or different subframes). In some embodiments, the SRS module  208  does not determine dynamically how to transmit, but rather checks its memory  204  to determine what approach had been established previously with the serving eNB  104 . This may also be referred to as a static approach. In other embodiments, the SRS module  208  dynamically determines how to transmit (e.g., what precoding to use, what order to use, etc.). For example, upon receipt of CSI-RS (or some other RS) from its serving eNB  104 , may analyze channel conditions based on the received RS to determine what precoding to use in the UL for the SRS. In yet other embodiments, the eNB  104  may provide instruction on what precoding the UE  102  should use. Where the eNB  104  provides instruction on what precoding to use for the SRS, the SRS module  208  may control respective aspects of the UE  102  in order to implement that instruction. 
     As shown, the transceiver  210  may include the modem subsystem  212  and the radio frequency (RF) unit  214 . The transceiver  210  can be configured to communicate bi-directionally with other devices, such as base stations  104  and/or other network elements. The modem subsystem  212  may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a polar coding scheme, etc. For example, this may be performed based on an allocation/assignment provided from the eNB  104  in response to the eNB  104 &#39;s receipt of both the precoded SRS and unprecoded SRS previously. The RF unit  214  may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem  212  (on outbound transmissions) or of transmissions originating from another source such as an eNB  104 . Although shown as integrated together in transceiver  210 , the modem subsystem  212  and the RF unit  214  may be separate devices that are coupled together at the UE  102  to enable the UE  102  to communicate with other devices. 
     The RF unit  214  may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information) such as SRS and PUSCH data of the present disclosure, to the antenna  216  for transmission to one or more other devices. The antenna  216  may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver  210 . As illustrated, antenna  216  may include multiple antennas in a MIMO configuration of similar or different designs in order to sustain multiple transmission links for such things as spatial diversity, for implementation of precoding according to embodiments of the present disclosure. 
       FIG. 3  is a block diagram of an exemplary wireless communication device  300  according to embodiments of the present disclosure. The wireless communication device  300  may be an eNB having any one of many configurations described above. For purposes of example, wireless communication device  300  may be an eNB  104  as discussed above with respect to  FIG. 1 . The eNB  104  may include a processor  302 , a memory  304 , a resource scheduling module  308 , a transceiver  310  (including a modem  312  and RF unit  314 ), and an antenna  316 . These elements may be in direct or indirect communication with each other, for example via one or more buses. 
     The processor  302  may have various features as a specific-type processor. For example, these may include a CPU, a DSP, an ASIC, a controller, an FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein with reference to the eNBs  104  introduced in  FIG. 1  above. The processor  302  may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The memory  304  may include a cache memory (e.g., a cache memory of the processor  302 ), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some embodiments, the memory  304  may include a non-transitory computer-readable medium. The memory  304  may store instructions  306 . The instructions  306  may include instructions that, when executed by the processor  302 , cause the processor  302  to perform operations described herein with reference to an eNB  104  in connection with embodiments of the present disclosure. 
     The resource scheduling module  308  may be used for various aspects of the present disclosure. The resource scheduling module  308  may include various hardware components and/or software components to assist in performing UL PUSCH scheduling, such as RB allocation, UL rank, UL MCS, etc., upon receiving precoded SRS and unprecoded SRS from UEs  102  (whether in the same subframe using TDM or FDM or different subframes). In making the determinations, the eNB  104  may use any combination of the precoded SRS and unprecoded SRS. For example, in MU-MIMO situations, the eNB  104  may use the precoded/unprecoded SRS to determine how to best consider UEs  102  jointly, or individual UEs  102  when single UE-MIMO exists. 
     For example, the resource scheduling module  308  may determine to use the received precoded SRS for one aspect of scheduling/assignment and the received unprecoded SRS for another aspect of scheduling/assignment based on existing channel conditions—e.g., unprecoded SRS for RB allocation, precoded SRS for rank assignment, and both for MCS scheduling. Any combination is possible of the SRS in order to arrive at scheduling/assignment according to embodiments of the present disclosure. 
     Further, the resource scheduling module  308  may determine PUSCH precoding parameters for the UE  102  and cause the transceiver  310  to transmit instruction regarding that determination to the UE  102 . For example, after receiving both precoded SRS and unprecoded SRS from an UE  102 , the resource scheduling module  308  may determine that the UE  102  will use the same precoding as was used for the SRS (e.g., because one or more signal characteristics from the SRS (precoded and/or unprecoded) meet one or more target thresholds). In that example, the resource scheduling module may set a single bit in a DL message (e.g., in the DL control channel) to signal the UE  102  (e.g., the bit asserted) to use the same precoding for PUSCH data transmission. When the same precoding is not going to be used, then the resource schedule module  308  may not set that bit (e.g., not asserted). Other approaches to signaling the precoding determination may alternatively be used as well. 
     Where the resource scheduling module  308  determines that the same precoding will not be used for data transmission in the PUSCH, it may determine what precoding to assign the UE  102  to use for the data. With that determination, the resource scheduling module  308  may then send the indication of the PUSCH data precoding to the UE  102 . In some examples, the resource scheduling module  308  may include the full precoding data (i.e., all parameters specified for the UE  102  to use) for use in PUSCH by the UE  102 . In other examples, the resource scheduling module  308  may reduce the signaling overhead involved by determining a delta between the precoding used for the SRS by the UE  102  and the precoding determined for use for the PUSCH data. The resource scheduling module  308  may cause the transceiver  310  transmit that delta, instead of the full details of the precoding for the PUSCH, to the UE  102 . This may provide more efficient use of resources as the signaling overhead may be reduced as compared to the other option. This may be a static arrangement between the UE  102  and the eNB  104  (i.e., preset prior to use) or dynamic with appropriate signaling between the devices to identify that the instruction is coming, and in what format. 
     As shown, the transceiver  310  may include the modem subsystem  312  and the RF unit  314 . The transceiver  310  can be configured to communicate bi-directionally with other devices, such as UEs  102  and/or other network elements. The modem subsystem  312  may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a polar coding scheme, etc. The RF unit  314  may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem  312  (on outbound transmissions) or of transmissions originating from another source such as a UE  102 . 
     Although shown as integrated together in transceiver  310 , the modem subsystem  312  and the RF unit  314  may be separate devices that are coupled together at the eNB  104  to enable the eNB  104  to communicate with other devices. The RF unit  314  may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information) to the antenna  316  for transmission to one or more other devices. The antenna  316  may further receive data transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver  310 . This may include, for example, receiving the precoded SRS and unprecoded SRS from UEs  102  and transmitting PUSCH data precoding assignments according to embodiments of the present disclosure. As illustrated, antenna  316  may include multiple antennas in a MIMO configuration of similar or different designs in order to sustain multiple transmission links. 
       FIG. 4  shows a block diagram illustrating communication between two wireless communication devices of a MIMO system  400  in accordance with the present disclosure. For sake of clarity in explanation, an eNB  104  and a UE  102  are shown. However, it is understood that the following description is applicable to communication between any two wireless communication devices in accordance with the present disclosure. Further, the following discussion will focus on those aspects pertinent to the present disclosure; as will be recognized, the elements of  FIG. 4  may be further used for other purposes. 
     At the eNB  104 , a transmit processor  420  may receive data from a data source  410  and control information from a controller/processor  440 . The data rate, coding, and modulation for each data stream may be determined by instructions performed by processor  430 . The transmit processor  420  may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. This may include, for example, symbol mapping based on a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM). A transmit (TX) multiple-input multiple-output (MIMO) processor  430  may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs)  432   a  through  432   t.    
     Each modulator  432  may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator  432  may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators  432   a  through  432   t  may be transmitted via antennas  434   a  through  434   t , respectively. As some examples, the antennas  434   a  through  434   t  may transmit DCI, RS, and regular data where the eNB  104  is the one serving the UE  102  that is the targeted recipient. Embodiments of the present disclosure include having multiple antennas. 
     At the UE  102 , antennas  452   a  through  452   r  may receive the downlink signals from the eNB  104  and may provide received signals to the demodulators (DEMODs)  454   a  through  454   r , respectively. Each demodulator  454  may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator  454  may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector  456  may obtain received symbols from all the demodulators  454   a  through  454   r , perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor  458  may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE  102  (e.g., RS, regular data, and PUSCH data precoding as just some examples pertinent to embodiments of the present disclosure), and provide decoded control information to a controller/processor  480 . 
     On the uplink, at the UE  102 , a transmit processor  464  may receive and process data from a data source  462  and control information from the controller/processor  480 . The data may include precoded SRS and unprecoded SRS, regular UL data precoded according to instructions from the eNB  104  and directed to the serving eNB  104 , and/or connection setup or response information. The transmit processor  464  may also generate other reference symbols for a reference signal. 
     The symbols from the transmit processor  464  may be precoded by a TX MIMO processor  466 , further processed by the modulators  454   a  through  454   r  (e.g., for SC-FDM, etc.), and transmitted to the eNB  104 . For example, for the precoded SRS, the weights may be processed by the modulators  454   a  through  454   r  to cause the MIMO antennas  452   a  through  452   r . At the eNB  104 , the uplink signals from the UE  102  may be received by the antennas  434 , processed by the demodulators  432 , detected by a MIMO detector  436 , if applicable, and further processed by a receive processor  438  to obtain decoded data and control information sent by the UE  102  (e.g., precoded SRS and unprecoded SRS). The processor  438  may provide the decoded data to a data sink and the decoded control information to the controller/processor  440 . 
     The controllers/processors  440  and  480  may direct the operation at the eNB  104  and the UE  102 , respectively. The controller/processor  440  and/or other processors and modules at the eNB  104  may perform or direct the execution of various processes for the techniques described herein, including sending SRS precoding information (where applicable), determining UL PUSCH scheduling based on precoded SRS and unprecoded SRS, and PUSCH data precoding assignments, etc. The controllers/processor  480  and/or other processors and modules at the UE  102  may also perform or direct the execution of the various processes for the techniques described herein, including determining particular SRS precoding parameters and determining PUSCH data precoding per eNB  104  instruction. 
     In this regard, the memories  442  and  482  may store data and program codes for the eNB  104  and the UE  102 , respectively, to perform or direct the execution of these various processes. A scheduler  444  may schedule wireless communication devices for data transmission on the downlink and/or uplink. 
       FIG. 5A  is a block diagram of an exemplary uplink frame structure  500  according to embodiments of the present disclosure. It provides an illustrative example of how an uplink subframe may be organized with respect to precoded SRS and unprecoded SRS when relying on TDM for transmitting both in a given subframe (whether using periodic or aperiodic SRS). A frame  502  may have a duration t (e.g., 10 ms) and may be divided into some number of equally sized subframes (e.g., 10). In other embodiments, the frame  502  may have a shorter duration (e.g., for higher frequency/latency requirement uses to name just one example). 
     Each subframe may include consecutive time slots, such as two. A resource grid may be used to represent two time slots, each time slot including a resource block (RB). Further, multiple RBs (e.g., representing multiple groupings of subcarriers) may be grouped together as the RBGs mentioned above with respect to  FIG. 1 . The resource grid (illustrated in  FIG. 5A  with respect to a particular RB) may be divided into multiple resource elements. For a cyclic prefix (e.g., according to LTE), a resource block may contain 12 consecutive subcarriers in the frequency domain and 7 consecutive OFDM symbols in the time domain, for a total of 84 resource elements. For an extended cyclic prefix, an RB may contain 12 consecutive subcarriers in the frequency domain and 6 consecutive OFDM symbols in the time domain, for a total of 72 resource elements. 
     According to embodiments of the present disclosure, the precoding for the SRS may be made on any of a variety of levels of granularity. For example, the precoding may be wideband, ranging down to narrowband (e.g., per tone precoding), with any value in between. 
     Some of the resource elements may include the UL SRS (precoded and/or unprecoded). In the example provided in  FIG. 5A , both precoded SRS and unprecoded SRS are provided in the same subframe according to TDM, such that each may use the same band (depending on granularity) of tones (frequencies) but at different scheduled time slots in the subframe.  FIG. 5A  provides an example only—the precoded SRS and unprecoded SRS may occur at any symbols of the subframe (e.g., may occur during any time slots designated therefore in the subframe). 
     The example particularly illustrated in  FIG. 5A  provides the first SRS  504  at a first time slot and the second SRS  506  at a second time slot following the first time slot. Although illustrated as being in contiguous time slots, the time slots used in the subframe may not be contiguous to each other. The first SRS  504  may be the precoded SRS and the second SRS  506  the unprecoded SRS, or vice versa. The other resource elements may include other control and/or data symbols for either UL, DL, or some combination of both. 
       FIG. 5B  is a block diagram of an exemplary uplink frame structure  520  according to alternative embodiments of the present disclosure. It provides an illustrative example of how an uplink subframe may be organized with respect to precoded SRS and unprecoded SRS when relying on FDM for transmitting both in a given subframe (whether using periodic or aperiodic SRS). For simplicity of discussion, the differences to  FIG. 5A  will be emphasized. 
     In the example of  FIG. 5B , both the precoded SRS and the unprecoded SRS are provided in the same subframe according to FDM, such that each may use the same time slot but different tones. Although illustrated as occupying a single time slot, the shared time resource may extend to more than one time slot, while still dividing up allocation of the frequencies of the resource block between the precoded SRS and unprecoded SRS in the relevant time slot(s). Again, the other resource elements may include other control and/or data symbols for either UL, DL, or some combination of both. 
       FIG. 5C  is a block diagram of an exemplary uplink frame structure  540  according to alternative embodiments of the present disclosure. It provides an illustrative example of how uplink subframes may be organized with respect to precoded SRS and unprecoded SRS when relying on use of multiple subframes for transmitting both (whether using periodic or aperiodic SRS). For simplicity of discussion, the differences to  FIG. 5A / 5 B will be emphasized. 
     In the example of  FIG. 5C , the precoded SRS and the unprecoded SRS are provided in different subframes identified as subframe i for SRS 1   504  and subframe i+j for SRS 2   506 . The subframes may be adjacent to each other in time (i.e., no intervening subframes between them) or not (i.e., one or more intervening subframes between them). The SRS 1   504  may be either the precoded SRS or the unprecoded SRS, with the SRS 2   506  being the other of the two. As illustrated, the SRS in each subframe does not need to be assigned to the same time and/or frequency resources as the other (though such may be the case). 
     Turning now to  FIG. 6 , a flowchart is illustrated of an exemplary method  600  for wireless communication in accordance with various aspects of the present disclosure. In particular, the method  600  illustrates the transmitting of precoded SRS and unprecoded SRS according to embodiments of the present disclosure. Method  600  may be implemented by a given UE  102  (any number of UEs  102 , with focus on one for simplicity of discussion herein). It is understood that additional steps can be provided before, during, and after the steps of method  600 , and that some of the steps described can be replaced or eliminated from the method  600 . 
     At block  602 , the UE  102  determines how to precode an SRS. This may be done, for example, the UE  102  may receive one or more downlink (DL) reference signals, such as CSI-RS, from an eNB  104  and, according to the channel quality of the DL channel determined from the reference signals, identify a direction that is desirable in which to steer a beam of the UE  102 . Where the eNB  104  provides instruction on a precoding to apply for SRS, the UE  102  may access that instruction at block  602 . 
     At block  604 , the UE  102  generates the precoded SRS according to the information determined from block  602 . 
     At block  606 , the UE  102  generates the unprecoded SRS. Although described as occurring at a subsequent block to block  604 , this may occur prior to or concurrent with block  604 . 
     At decision block  608 , if TDM is used for conveying the precoded SRS and unprecoded SRS to the eNB  104 , then the method  600  proceeds to block  610 . As noted previously, whether to use TDM may have been established previously between the UE  102  and the eNB  104 . 
     At block  610 , the UE  102  places the precoded SRS and the unprecoded SRS into the same subframe in different symbol periods. These may be adjacent time slots (symbol periods) or nonadjacent. 
     Returning to decision block  608 , if TDM is not used, then the method  600  may instead proceed to decision block  612 . 
     At decision block  612 , if FDM is used for conveying the precoded SRS and the unprecoded SRS to the eNB  104 , then the method  500  proceeds to block  614 . 
     At block  614 , the UE  102  places the precoded SRS and the unprecoded SRS into the same subframe in different tones (frequency elements) at the same time slot (symbol period). 
     Returning to decision block  612 , if FDM is not used, then the method  600  may instead proceed to block  616 . 
     At block  616 , since TDM and FDM are not being used, the UE  102  places the precoded SRS and the unprecoded SRS into different subframes. These subframes may be adjacent to each other or have one or more intervening subframes. Further, the particular resource elements used in each subframe may vary from each other and over time. 
     From any of blocks  610 ,  614 , or  616 , the method  600  proceeds to block  618 . 
     At block  618 , the UE  102  transmits the precoded SRS and the unprecoded SRS to the eNB  104  according to the approach taken to place the precoded SRS and unprecoded SRS into one or more subframes. 
     At block  620 , the UE  102  may receive data precoding instruction from the eNB  104  for use in the PUSCH. Although illustrated as following each SRS transmission, multiple SRS transmissions may occur between precoding assignments for PUSCH data transmissions. 
     At decision block  622 , if the data precoding instruction identifies that the UE  102  should use the same precoding as was used for the precoded SRS, then the method  600  proceeds to block  624 . This may be identified by the setting of a given bit in a DL message from the eNB  104 , which the UE  102  checks for in DL messages it receives. 
     At block  624 , the UE  102  applies the same precoding as was used for the SRS to the antennas for use in transmission of data on the PUSCH to the eNB  104 . 
     Returning to decision block  622 , if the data precoding instruction does not identify that the same precoding should be used, then the method  600  instead proceeds to decision block  626 . This may be identified by checking the DL messages for the bit in the header and that it is not set. 
     At decision block  626 , the UE  102  proceeds with determining whether the eNB  104  uses delta signaling to identify the precoding to be used for PUSCH data. This may be determined by checking a procedure previously agreed upon between the devices or based upon an explicit identification from the eNB  104  at the time that delta signaling is to be used. If delta signaling is used, then the method  600  proceeds to block  628 . 
     At block  628 , the UE  102  obtains the delta information received from the eNB  104  and derives the data precoding to be used on the PUSCH data. For example, the UE  102  may recover the precoding for PUSCH by adding or multiplying the delta information with the precoding previously used for the SRS (whether addition or multiplication is used may be configured previously between the eNB  104  and UE  102 , such as at device initialization or other time). 
     At block  630 , the UE  102  applies the precoding derived from block  628  for use in transmission of data on the PUSCH to the eNB  104 . 
     Returning to decision block  626 , if it is determined that the eNB  104  did not use delta signaling, then the method  600  proceeds to block  632 . 
     At block  632 , the UE  102  extracts the explicitly identified precoding data for use in PUSCH data by the UE  102 . This may be extracted from a DL message from the eNB  104  that was received previously or at the time. 
     From any of blocks  624 ,  630 , or  632 , the method  600  proceeds to block  634 . 
     At block  634 , the UE  102  transmits data on the PUSCH with precoding as determined from blocks  624 ,  630 , or  632  as the case may be. 
     The above actions may repeat during operation (e.g., SRS either periodically or aperiodically and likewise for the PUSCH precoding assignments). 
     Turning now to  FIG. 7 , a flowchart is illustrated of an exemplary method  700  for wireless communication in accordance with various aspects of the present disclosure. In particular, the method  700  illustrates the reception and processing of precoded SRS and unprecoded SRS according to embodiments of the present disclosure. Method  700  may be implemented by an eNB  104  (any number of eNBs  104  in communication with any number of UEs  102 , focusing on one for simplicity of discussion here). It is understood that additional steps can be provided before, during, and after the steps of method  700 , and that some of the steps described can be replaced or eliminated from the method  700 . 
     At decision block  702 , if the precoded SRS and unprecoded SRS are not received in the same subframe, then the method  700  proceeds to block  704 . 
     At block  704 , the eNB  104  receives a first SRS in a first subframe. For example, the first SRS may be a precoded SRS. Alternatively, the first SRS may be an unprecoded SRS. 
     At block  706 , the eNB  104  receives a second SRS in a second subframe that occurs after the first subframe. For example, the second SRS may be an unprecoded SRS. Alternatively, the second SRS may be a precoded SRS (either way, one is unprecoded and the other precoded in respective subframes). 
     Returning to decision block  702 , if the precoded SRS and unprecoded SRS are received in the same subframe, then the method  700  proceeds to decision block  708 . 
     At decision block  708 , if TDM is used then the method  700  proceeds to block  710 . 
     At block  710 , the eNB  104  receives a first SRS in a first symbol period of a given subframe. For example, the first SRS may be a precoded SRS. Alternatively, the first SRS may be an unprecoded SRS. 
     At block  712 , the eNB  104  receives a second SRS in a second symbol period that is different from the first symbol period but still in the same given subframe. For example, the second SRS may be an unprecoded SRS. Alternatively, the second SRS may be a precoded SRS. 
     Returning to decision block  708 , if TDM is not used then the method  700  proceeds to block  714 . 
     At block  714 , the eNB  104  receives a first SRS on a first set of frequency resources (tones) of a given subframe. For example, the first SRS may be a precoded SRS. Alternatively, the first SRS may be an unprecoded SRS. 
     At block  716 , the eNB  104  receives a second SRS on a second set of frequency resources different from the first set of frequency resources but still in the same given subframe at time slot. For example, the second SRS may be an unprecoded SRS. Alternatively, the second SRS may be a precoded SRS. Although blocks  714  and  716  are listed separately, these actions may occur together at the eNB  104  as each is received at the same time slot(s), albeit at different frequency resources. 
     From any of blocks  706 ,  712 , and  716 , the method  700  proceeds to block  718 . 
     At block  718 , the eNB  104  determines what data precode assignment for PUSCH to provide to the UE  102 , and how to provide the assignment to the UE  102 . 
     At decision block  720 , if the same precoding assignment for PUSCH as was used for the precoded SRS is made, then the method  700  proceeds to block  722 . 
     At block  722 , the eNB  104  generates an indication for the UE  102  to use the same precoding. For example, the eNB  104  may set a bit in a DL control message (e.g., asserting it to indicate to use the same precoding). 
     Returning to decision block  720 , if the same precoding assignment is not intended for the PUSCH, then the method  700  proceeds to decision block  724 . 
     At decision block  724 , if the eNB  104  is using delta signaling to identify the data precoding for PUSCH, then the method  700  proceeds to block  726 . 
     At block  726 , the eNB  104  generates the delta between the target data precoding for PUSCH and the precoding that the UE  102  used for the previously received precoded SRS. This may be generated so that the UE  102  uses addition to recreate the precoding assignment, or alternatively multiplication depending on how previously established between the entities. 
     Returning to decision block  724 , if the eNB  104  is not using delta signaling to identify the data precoding for PUSCH, then the method  700  proceeds to block  728 . 
     At block  728 , the eNB  104  generates a full identification of the data precoding for the PUSCH, which will be included in a DL message to the UE  102 . 
     From any of blocks  722 ,  726 , and  728 , the method  700  proceeds to block  730 . 
     At block  730 , the eNB  104  sends the data precode instruction to the UE  102  for the UE  102  to use in UL PUSCH transmissions. 
     Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. 
     The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration). 
     The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. 
     Also, as used herein, including in the claims, “or” as used in a list of items (for example, a list of items prefaced by a phrase such as “at least one of” or “one or more of”) indicates an inclusive list such that, for example, a list of [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). It is also contemplated that the features, components, actions, and/or steps described with respect to one embodiment may be structured in different order than as presented herein and/or combined with the features, components, actions, and/or steps described with respect to other embodiments of the present disclosure. 
     As those of some skill in this art will by now appreciate and depending on the particular application at hand, many modifications, substitutions and variations can be made in and to the materials, apparatus, configurations and methods of use of the devices of the present disclosure without departing from the spirit and scope thereof. In light of this, the scope of the present disclosure should not be limited to that of the particular embodiments illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.