Patent Publication Number: US-9432979-B1

Title: Method for semi-statically adapting uplink multiple-input multiple-output transmission

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 12/577,105, filed Oct. 9, 2009, the disclosure of which is hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a method and system for performing an uplink transmission with a base station. The present invention further relates to applying a customized precoding to a transmitting unit of a wireless terminal device. 
     INTRODUCTION 
     The Third Generation Partnership Project (3GPP) is developing a Long Term Evolution (LTE) standard using a physical layer based on globally applicable evolved universal terrestrial radio access (E-UTRA). In release-8 specification of LTE, an LTE base station, referred to as an enhanced Node-B (eNB), may use an array of four antennas, or even more with antenna virtualization, to broadcast a signal to a piece of user equipment (UE), such as a wireless terminal device. 
     Depending on different channel condition, eNB may instructs a UE on how to use its multiple antennas in the uplink transmission. For example in the case of precoding, the UE may apply a different weighting and phase offset to the signal to be sent from each of the transmit antenna. A precoding operation may be represented mathematically by a vector of complex-valued weightings applied onto the transmission signal of each antenna. The eNB may dynamically instruct a precoding matrix index (PMI), selected from a pre-defined set of matrices known to the UE. The pre-defined set of matrices is known as a codebook. 
     SUMMARY OF THE INVENTION 
     A method, a wireless terminal device, and a base station are disclosed. A receiving unit may receive from a base station an antenna precoding instruction for an uplink transmission. A processor may execute a modification of the antenna precoding instruction according to a transmit antenna adapter into a customized precoding. A transmitting unit may perform the uplink transmission according to the customized precoding. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates in a block diagram one embodiment of a communication system. 
         FIG. 2  illustrates a possible configuration of a computing system to act as a base transceiver station. 
         FIG. 3  illustrates, in a block diagram, one embodiment of a mobile system or electronic device to create a radio connection. 
         FIG. 4  illustrates, in a block diagram, one embodiment of a transceiver. 
         FIG. 5  illustrates, in a block diagram, one embodiment of a control message transmission. 
         FIG. 6  illustrates, in a block diagram, one embodiment of an adapter message transmission. 
         FIG. 7  illustrates, in a flowchart, one embodiment of a method for receiving an uplink transmission. 
         FIG. 8  illustrates, in a flowchart, one embodiment of a method for performing an uplink transmission with a base station created transmit antenna adapter. 
         FIG. 9  illustrates, in a block diagram, one embodiment of a feedback message transmission. 
         FIG. 10  illustrates, in a block diagram, one embodiment of a modification/confirmation message transmission. 
         FIG. 11  illustrates, in a flowchart, one embodiment of a method for performing an uplink transmission with a user equipment created transmit antenna adapter. 
         FIG. 12  illustrates, in a flowchart, one embodiment of a method for modifying an antenna precoding instruction with a transmit antenna adapter. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth herein. 
     Various embodiments of the invention are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the invention. 
     The present invention comprises a variety of embodiments, such as a method, a mobile system, and a mobile network operator, and other embodiments that relate to the basic concepts of the invention. The mobile system may be any manner of computer, mobile device, or wireless communication device. 
     A method, a wireless terminal device, and a base station are disclosed. A receiving unit may receive from a base station an antenna precoding instruction for an uplink transmission. A processor may execute a modification of the antenna precoding instruction according to a transmit antenna adapter into a customized precoding. A transmitting unit may perform the uplink transmission according to the customized precoding. 
     A wireless terminal device with multiple transmit (Tx) antennas, due to different form factor constraints, may have many potential antenna implementations, including different antenna spacing, the use of dual-polarized or linear-polarized antenna elements, and various degrees of antenna coupling. Different antenna implementations tailored for different device form factors may often result in different levels of transmit antenna correlation, and differing antenna efficiencies. In addition, various propagation scenarios in which the devices are used, such as the hand-grip posture for handheld devices and usage posture for notebooks, may affect the antenna correlation and efficiency. The transmit antenna correlation may be learned at the base station when the channel corresponding to each of the transmit antennas of a wireless device may be estimate from an uplink sounding signal transmission. Alternatively, the wireless terminal device may estimate the transmit antenna correlation from estimating the receive antenna correlation, assuming the set of transmit antennas is a subset of the receive antennas and the downlink to uplink reciprocity holds. Even if not, the wireless terminal device may extract some coarse characteristics embedded in the receive antenna correlation. Depending on the observed channel statistics, especially the long-term property caused by antenna implementation, configuration, or usage posture, the uplink multiple-input multiple-output transmission may adapt to these channel statistics. 
     One case where the configuration of antennas may be adapted is when the implantation of a user equipment device may have antenna efficiency difference, also called gain imbalance. To deal with gain imbalance, a base station may use only a subset of the terminal antennas for uplink transmission, referred to as a reduced-dimension precoding. One way to support a reduced dimension precoding may be to define a “master” codebook that covers all the possibilities of dimension reduction. Since the activated antenna subset depends on the antenna configuration and usage posture, the master codebook may have to accommodate multiple possibilities, and therefore include many reduced-dimension codebooks that are essentially the same except that they apply to different antenna subset groupings. However, defining the master codebook to include basically multiple replicas of the same reduced dimension codebook to cover all possibilities may not be efficient, since the amount of control signaling may grow with the size of the codebook. Generally, the optimal choice of subset may change relatively slowly. This may be due to the optimal choice of subsets being primarily influenced by antenna gain imbalance. Antenna gain imbalance may be influenced, in turn, by such events as change in user hand grip, user posture, and antenna configuration, which occur infrequently relative to the rate of signaling the choice of precoding matrix within the codebook. While replicating a base codebook to address all permutations of antenna indexing is possible, such replication may not be the most efficient approach when re-indexing is needed fairly infrequently. 
     In another situation, the codebook may be defined with a particular antenna type and indexing in mind which does not match the actual implementation. In this case, the base station may change the antenna indexing. Such a decision may be based on the uplink channel observed at the base station based on the sounding signal transmitted from the user device. Precoding performance may be improved if the optimal antenna indexing is adjusted. The change in antenna indexing may be done once by a user equipment device autonomously or according to some criteria defined by the base station. Once defined, the user equipment may use the antenna indexing in all subsequent uplink transmissions, including the transmission of a sounding signal. In an alternative procedure, the user equipment may sound from antennas with a first indexing which serve as a reference index, and then potentially be changed by the base station based on the received sounding signal. In such cases the base station may signal the new antenna indexing. The appropriate indexing may change according to hand grip and user posture. Ideally, the base station may optimally determine the appropriate indexing on a semi-static basis, according to the antenna implementation, usage posture, and the predefined codebook. The base station may convey such antenna re-indexing to a user equipment device. 
     Similar to antenna indexing, the user equipment device may group antennas based on a property to best match the predefined codebook. For example, antenna of the same or orthogonal polarization, or antennas of close spacing, may be grouped together so that precoding may better exploit high antenna correlation for transmission directivity gain and low antenna correlation for spatial multiplexing gain. Antenna grouping may be achieved through re-indexing. 
     Overall, the antenna characteristics inherent to the implementation and some long-term propagation behavior may affect the long-term behavior of the channel significantly. Semi-static notification of antenna indexing, or grouping, or subset selection may be beneficial. 
       FIG. 1  illustrates one embodiment of a communication system  100 . The communication system  100  may include a core mobile network  102  that may be accessed by at least one mobile device  104 , such as a wireless terminal device, or user equipment (UE). The wireless terminals  104  may be fixed or mobile. The wireless terminals  104  may also be referred to as subscriber units, mobiles, mobile stations, user, terminals, subscriber stations, user terminals, wireless communication devices, user devices, or by other terminology used in the art. Various communication devices may exchange data or information through the core mobile network  102 . The core mobile network  102  may be a WiMAX network, a universal terrestrial radio access network (UTRAN) cellular network, an evolved UTRAN (E-UTRAN) cellular network, or other type of telecommunication network. A server or a series of servers controlled by a network operator, referred to herein as a network operator server  106 , or a mobile network operator  106 , may administer the network. The network operator server  106  may maintain a set of data to facilitate access of the core mobile network  102  by the wireless terminal device  104 . The mobile system  104  may access the network via a network base station  108 . A base unit  108  may also be referred to as an access point, access terminal, base, base station, Node-B, eNode-B, Home Node-B, Home eNode-B, relay node, or by other terminology used in the art. 
       FIG. 2  illustrates a possible configuration of a computing system  200  to act as a network operator server  106  or a network base station  108 . The computing system  200  may include a controller/processor  210 , a memory  220 , a database interface  230 , a transceiver  240 , input/output (I/O) device interface  250 , and a network interface  260 , connected through bus  270 . The network server  200  may implement any operating system. Client and server software may be written in any programming language, such as C, C++, Java or Visual Basic, for example. The server software may run on an application framework, such as, for example, a Java® server or .NET® framework 
     The controller/processor  210  may be any programmed processor known to one of skill in the art. However, the disclosed method may also be implemented on a general-purpose or a special purpose computer, a programmed microprocessor or microcontroller, peripheral integrated circuit elements, an application-specific integrated circuit or other integrated circuits, hardware/electronic logic circuits, such as a discrete element circuit, a programmable logic device, such as a programmable logic array, field programmable gate-array, or the like. In general, any device or devices capable of implementing the disclosed method as described herein may be used to implement the disclosed system functions of this invention. 
     The memory  220  may include volatile and nonvolatile data storage, including one or more electrical, magnetic or optical memories such as a random access memory (RAM), cache, hard drive, or other memory device. The memory may have a cache to speed access to specific data. The memory  220  may also be connected to a compact disc-read only memory (CD-ROM), digital video disc-read only memory (DVD-ROM), DVD read write input, tape drive, or other removable memory device that allows media content to be directly uploaded into the system. 
     Data may be stored in the memory or in a separate database. The database interface  230  may be used by the controller/processor  210  to access the database. The database may contain subscriber information for each mobile system  104  that may access the mobile network  102 . Further, the database may maintain network performance data, such as network topology, network geographic location and peer proximity, network load distribution, and other network data. 
     The transceiver  240  may create a connection with the mobile device  104 . The transceiver  240  may be incorporated into a base station  200  or may be a separate device. 
     The I/O device interface  250  may be connected to one or more input devices that may include a keyboard, mouse, pen-operated touch screen or monitor, voice-recognition device, or any other device that accepts input. The I/O device interface  250  may also be connected to one or more output devices, such as a monitor, printer, disk drive, speakers, or any other device provided to output data. The I/O device interface  250  may receive a data task or connection criteria from a network administrator. 
     The network connection interface  260  may be connected to a communication device, modem, network interface card, a transceiver, or any other device capable of transmitting and receiving signals from the network. The network connection interface  260  may be used to connect a client device to a network. The components of the network server  200  may be connected via an electrical bus  270 , for example, or linked wirelessly. 
     Client software and databases may be accessed by the controller/processor  210  from memory  220 , and may include, for example, database applications, word processing applications, as well as components that embody the disclosed functionality of the present invention. The network server  200  may implement any operating system. Client and server software may be written in any programming language. Although not required, the invention is described, at least in part, in the general context of computer-executable instructions, such as program modules, being executed by the electronic device, such as a general purpose computer. Generally, program modules include routine programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that other embodiments of the invention may be practiced in network computing environments with many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. 
       FIG. 3  illustrates one embodiment of a wireless terminal device  300 , capable of acting as a mobile system or electronic device. For some embodiments of the present invention, the mobile device  300  may also support one or more applications for performing various communications with a network. The mobile device  300  may be a handheld device, such as, a mobile phone, a laptop, or a personal digital assistant (PDA). For some embodiments of the present invention, the user device  300  may be WiFi® capable device, which may be used to access the network mobile for data or by voice using VOIP. 
     The mobile device  300  may include a transceiver  302 , which is capable of sending and receiving data over the mobile network  102 . The mobile device  300  may include a processor  304  that executes stored programs. The mobile device  300  may also include a volatile memory  306  and a non-volatile memory  308  to act as data storage for the processor  304 . The mobile device  300  may include a user input interface  310  that may comprise elements such as a keypad, display, touch screen, and the like. The mobile device  300  may also include a user output device that may comprise a display screen and an audio interface  312  that may comprise elements such as a microphone, earphone, and speaker. The mobile device  300  also may include a component interface  314  to which additional elements may be attached, for example, a universal serial bus (USB) interface or a geographical positioning system (GPS). Finally, the mobile device  300  may include a power supply  316 . 
       FIG. 4  illustrates one embodiment of a transceiver  302 . A terminal interface  402  may send received signals to the UE device  104  and receive transmissions from the UE device  104 . A controller  404  may configure a transmitting unit  406  according to an antenna codebook received from the base station  108  by a receiving unit  408 . Alternately, the transceiver  302  may forgo the controller  404  and have the configuration performed by the processor  304  of the UE device  104 . 
     The base station  108  may send the antenna precoding instruction to the UE device  104  in a control message transmission.  FIG. 5  illustrates one embodiment of a control message transmission  500 . The control message transmission  500  may have a transmission format field  502  to indicate the format of the subsequent transmissions. The control message transmission  500  may have a cyclical redundancy check (CRC) filed  504  to aid in determining if the message is correctly by the UE device  104 . The control message transmission  500  may have power control information  506  to aid the UE device  104  in setting its transmit power. The control message transmission  500  may have an antenna codebook  508  describing one or more antenna precoding instruction  510  to indicate to the UE device  104  the precoding matrix to be used on a subsequent matrix to be used on a subsequent uplink transmission. The base station  108  may send the control message transmission  500  on a recurring basis to the UE device  104 . 
     The antenna codebook may be customized to an individual UE device  104  using a transmit antenna adapter. The base station  108  may send a representation of a transmit antenna adapter to the UE device  104  in an adapter message transmission.  FIG. 6  illustrates one embodiment of an adapter message transmission  600 . The adapter message transmission  600  may have a CRC  602  to aid in the detection of errors in the message received by the UE device  104 . The adapter message transmission  600  may have a UE ID  604  for the UE device  104  and a message length field  606 . The adapter message transmission  600  may have a transmit antenna adapter representation  608  describing a transmit antenna adapter. The transmit antenna adapter may modify an antenna precoding instruction  510  to instruct a transmitting unit  406  to configure a set of transmit antennas. The base station may also send the adapter message transmission  600  on a recurring basis to the UE device  104 . The base station may send the adapter message transmission  600  at a different interval from the control message transmission  500 . 
     The antenna adapter may be represented in various forms, but more generically as a matrix “A” to be used in uplink transmission, possibly together with the precoding matrix V P×N , in the following equation:
 
 X   M     T     ×N   =A   M     T     ×P   *V   P×N   *S   N×1  
 
where X M     T     ×N  is the transmitted signal from all M T  antennas for N streams or layers of data represented by S N×1  (i.e., rank-N), and V P×N  is the precoding matrix of dimension P rows, where the value P is between N and M T . The precoding matrix V P×N  may be absent if it is an identity matrix. In one embodiment, the transmit antenna adapter representation  608  may be a bit field, which indicates the antenna adapter to be applied. A bit field of with a value of “0”, for example, may indicate for the UE device  104  to use the adapter described by the matrix A M     T     ×P  (0), while a bit field with a value of “1” may indicate for the UE device  104  to use the adapter described by the matrix A M     T     ×p  (1), A M     T     ×P (0) and A M     T     ×P (1) where represent two possible adapters in a set of possibilities. The transmit antenna adapter may modify the antenna precoding instruction  510  according to multiple schemes indicated in the adapter representation, including antenna subset selection, antenna index permutation, or antenna pattern virtualization. For example, when the transmit antenna adapter modifies the antenna precoding instruction  510  by antenna subset selection, the matrix A M     T     ×P  may be an antenna subset selection matrix. A subset selection matrix may be a matrix with entries with values of either “0” or “1”, have at most one “1” in each row. For example, if antenna 1 and 3 is selected for transmission out of all 4 UE antennas, the matrix A M     T     ×P  is a selection matrix and may be represented as:
 
     
       
         
           
             
               A 
               
                 
                   M 
                   T 
                 
                 × 
                 P 
               
             
             = 
             
               
                 [ 
                 
                   
                     
                       1 
                     
                     
                       0 
                     
                   
                   
                     
                       0 
                     
                     
                       0 
                     
                   
                   
                     
                       0 
                     
                     
                       1 
                     
                   
                   
                     
                       0 
                     
                     
                       0 
                     
                   
                 
                 ] 
               
               . 
             
           
         
       
     
     As described earlier, a UE device  104  may implicitly index the antennas when performing uplink sounding signal transmission. The base station  108  may want to re-index the antennas based on the observed long-term statistics so that a codebook may deliver better performance, as opposed to the original codebook without antenna re-indexing. The original codebook without re-indexing may be represented by an identity matrix A M     T     ×P =I 4×4 . The base station  108  may request the UE device  104  to re-index its transmit antennas by sending an adapter message transmission  600  indicating the transmit antenna adapter may re-index the transmit antennas. The re-indexing may be represented by a permutation matrix A M     T     ×P . A permutation matrix may be a matrix with exactly one entry in each column equal to “1” and the remaining entries equal to “0”. For example, the UE device  104  may re-index the 4 antennas to [1,3,2,4] with the following permutation matrix: 
     
       
         
           
             
               A 
               
                 
                   M 
                   T 
                 
                 × 
                 P 
               
             
             = 
             
               
                 [ 
                 
                   
                     
                       1 
                     
                     
                       0 
                     
                     
                       0 
                     
                     
                       0 
                     
                   
                   
                     
                       0 
                     
                     
                       0 
                     
                     
                       1 
                     
                     
                       0 
                     
                   
                   
                     
                       0 
                     
                     
                       1 
                     
                     
                       0 
                     
                     
                       0 
                     
                   
                   
                     
                       0 
                     
                     
                       0 
                     
                     
                       0 
                     
                     
                       1 
                     
                   
                 
                 ] 
               
               . 
             
           
         
       
     
     The base station  108  may determine, on a semi-static basis, the best antenna indexing based on the antenna correlation observed. More specifically, the base station  108  may decide which permutation gives the best performances under the observed antenna correlation. The decision may be specific to an implementation based on, for example, criterion used in typical codebook design. The codebook design criterion may include, for example, minimal codeword distance. 
     Not limited to antenna selection or indexing, another scheme for modifying the antenna precoding may employ the adapter matrix A M     T     ×P  based on the user equipment transmit antenna correlation or covariance matrix “R”. In a particular example, A M     T     ×P =R 1/2 , or the square root of “R”, may be used for adaptive uplink precoding. Here “R” may be the correlation or covariance matrix of the vector of channels corresponding to the link between each of the transmit antennas and a certain receive antenna, or the average of several such covariance matrices, with each corresponding to one receive antenna of the base unit. In general, “antenna pattern virtualization” may be referred to as the process of applying a unitary matrix to transform a set of physical antennas to a set of virtualized antennas via weighting the set of physical antennas according to the unitary matrix. The above covariance matrix based antenna adaption scheme may be referred to as antenna pattern virtualization. 
     Regardless of which of the three methods of transmit antenna adaption used: subset selection, antenna re-indexing, or covariance matrix-based pattern virtualization, and thus the form of the adapter matrix A M     T     ×P ; the user equipment may combine the precoding matrix index indicated in the precoding instruction, represented by V P×N , with the adapter matrix A M     T     ×P  to determine the actual precoding matrix. If more than one non-zero entry is present in any row of the combined precoding matrix A M     T     ×P *V P×N , the emitted signal on the corresponding antenna may be the weighted superposition of two or more waveforms. 
     Note that the three methods of transmit antenna adaptation mentioned: subset selection, antenna re-indexing, or covariance matrix-based pattern virtualization, may be applied to a submatrix of the precoding matrices. For example, with three layers or data streams, the precoding matrix V P×N  may have three columns. A submatrix having only two columns, for example, may be adapted according to the adapter, instead of having the whole matrix adapted. In other words, the adapter matrix may apply to the submatrix of any precoding matrix indicated in the precoding instruction. 
       FIG. 7  illustrates one embodiment  700  of a method for receiving an uplink transmission. The base station  108  may receive an uplink transmission from the UE device  104  (Block  702 ). The base station  108  may obtain an uplink channel correlation of the uplink transmission (Block  704 ). The base station  108  may determine a transmit antenna adapter based on the uplink channel correlation and a codebook (Block  706 ). The decision may also be based on an uplink channel correlation obtained from the uplink transmission and the precoding indicated by the antenna precoding instruction. The transmit antenna adapter may be a set of modifications to the precoding operation in order to make the antenna precoding instruction  510  better match the antenna configuration of the UE device  104  and the transmission characteristics of the uplink transmission. The base station  108  may send the UE device  104  an antenna precoding instruction  510  for an uplink transmission (Block  708 ). The base station  108  may send the antenna precoding instruction  510  on a recurring basis. The base station  108  may send a transmit antenna adapter representation to the UE device  102  (Block  710 ). The transmit antenna adapter representation may describe to the UE device  104  the transmit antenna adapter. The base station  108  may send the transmit antenna adapter representation on a different interval than the antenna precoding instruction  510 . 
       FIG. 8  illustrates one embodiment of a method  800  for performing an uplink transmission with a base station created transmit antenna adapter. The UE device  104  may transmit from a set of antennas to allow the base station  108  to estimate the uplink channel (Block  802 ). The UE device  104  may receive from the base station  108  a control message transmission  500  containing an antenna precoding instruction  510  for an uplink transmission (Block  804 ). The UE device  104  may receive from the base station  108  a transmit antenna adapter representation (Block  806 ). The UE device  104  may receive both the antenna precoding instruction  510  and the antenna adapter representation on a recurring basis. The UE device  104  may receive the antenna precoding instruction  510  on a different interval than the transmit antenna adapter representation. The UE device  104  may execute a modification of the antenna precoding instruction  510  into a customized precoding according to a transmit antenna adapter (Block  808 ). The UE device  104  may then perform the uplink transmission according to the customized precoding (Block  810 ). 
     Alternatively, a UE device  104  may adapt the transmit antennas autonomously based on measurement of the downlink channel and may communicate the information back to the base station  108 . The downlink measurement may capture the uplink channel in case of a time division duplexing system which may have channel reciprocity between uplink and downlink. Even in frequency division duplexing, a UE device  104  may still be able to extract a transmit antenna property to make a decision on the preferred antenna adaptation. 
     The UE device  104  may determine the transmit antenna adapter based on a downlink transmission. The UE device  104  may then send a representation of a UE-preferred transmit antenna adapter to the base station  108  for confirmation in a feedback message transmission.  FIG. 9  illustrates one embodiment of a feedback message transmission  900 . The feedback message transmission  900  may have a CRC  902  to aid in the detection of errors in the message received by the base station  108 . The feedback message transmission  900  may have a message length field  904  for the base station  108 . The feedback message transmission  900  may have a UE-preferred transmit antenna adapter representation  906  describing a preferred or recommended transmit antenna adapter. The transmit antenna adapter may modify an antenna precoding instruction  510  to instruct a transmitting unit  406  to configure a set of transmit antennas. The transmit antenna adapter may modify the antenna precoding instruction  510  as an antenna subset selection, an antenna index permutation, and an antenna pattern virtualization. 
     The base station  108  may review the UE-preferred transmit antenna adapter review representation  908  and make some modifications or just confirm. The base station  108  may send these modifications or confirmations to the UE device  104  in a modification/confirmation message transmission.  FIG. 10  illustrates, in a block diagram, one embodiment of a modification/confirmation message transmission. The modification/confirmation message transmission  1000  may have a CRC  1002  aid the UE device  104  in determining if an error was mad in the reception of the message. The modification/confirmation message transmission  1000  may have a UE ID  1004  for the UE device  104  and a message length field  1006  for the base station  108 . The modification/confirmation message transmission  1000  may have a modified transmit antenna adapter representation  1008  describing a modified transmit antenna adapter or confirmation that the UE-preferred adapter is accepted as the transmit antenna adapter. The transmit antenna adapter may modify an antenna precoding instruction  510  to instruct a transmitting unit  406  to configure a set of transmit antennas. The transmit antenna adapter may modify the antenna precoding instruction  510  as an antenna subset selection  1010 , an antenna index permutation  1012 , and an antenna pattern virtualization  1014 . 
       FIG. 11  illustrates one embodiment of a method  1100  for performing an uplink transmission with a UE determined transmit antenna adapter. The UE device  104  may measure the downlink channel of the down link transmission from the base station  108  (Block  1102 ). The UE device  104  may determine a UE-preferred transmit antenna adapter based on the downlink channel (Block  1104 ). The UE device  104  may send a transmit antenna adapter representation describing the UE-preferred transmit antenna adapter to the base station  108  (Block  1106 ). After the base station  108  has reviewed the transmit antenna adapter representation, the UE device  104  may receive a modified antenna adapter representation or a confirmation from the base station (Block  1108 ). The UE device  104  may receive from the base station  108  an antenna codebook containing an antenna precoding instruction  510  for an uplink transmission (Block  1110 ). The UE device  104  may execute a modification of the antenna precoding instruction  510  into a customized precoding according to a transmit antenna adapter (Block  1112 ). The UE device  104  may then perform the uplink transmission according to the customized precoding (Block  1114 ). 
       FIG. 12  illustrates one embodiment of a method  1200  for modifying an antenna precoding instruction  510  with a transmit antenna adapter. The antenna precoding instruction  510  may be formatted as an index into a codebook having a set of a precoding matrix. The UE device  104  may apply a precoding entry on all or a subset of transmit antennas chosen according to the transmit antenna adapter (Block  1202 ). The UE device  104  may execute a permutation of the precoding matrix according to an antenna permutation indicated by the transmit antenna adapter (Block  1204 ). The permutation may be on the rows of the precoding matrix, or rows of a submatrix of the precoding matrix. The UE device  104  may multiply the precoding matrix on the left by a unitary matrix indicated by the transmit antenna adapter to transform a set of physical antennas to a set of virtualized antennas via weighting the set of physical antennas according to the unitary matrix (Block  1206 ). 
     Embodiments within the scope of the present invention may also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or combination thereof) to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of the computer-readable media. 
     Embodiments may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked (either by hardwired links, wireless links, or by a combination thereof) through a communications network. 
     Computer-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in stand-alone or network environments. Generally, program modules include routines, programs, objects, components, and data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps. 
     Although the above description may contain specific details, they should not be construed as limiting the claims in any way. Other configurations of the described embodiments of the invention are part of the scope of this invention. For example, the principles of the invention may be applied to each individual user where each user may individually deploy such a system. This enables each user to utilize the benefits of the invention even if any one of the large number of possible applications do not need the functionality described herein. In other words, there may be multiple instances of the electronic devices each processing the content in various possible ways. It does not necessarily need to be one system used by all end users. Accordingly, the appended claims and their legal equivalents should only define the invention, rather than any specific examples given.