AU2012203494B2 - Feedback signaling error detection and checking in MIMO wireless communication systems - Google Patents

Abstract

A method of feedback in a wireless transmit receive unit includes providing a preceding matrix (PMI), error checking the (PMI) to produce an error check (EC) bit, coding the PMI and the EC bit and transmitting the coded PMI and EC bit. 302- 30 306 31 308 310 312 Zoo PML1 P ML2 PML3 ' . * PMN- PML ..E CHJfFANNEL 314- F IG.3 400 402 404 406 408 410 412 414 416 418 42 422- 42 PML1 PML2 PML3 ELC() PML4 PML5 6 EC(LN-2PML N-1PMLN Ec(G) 507504--- 50 50 512 514- 522-, 524 526 508 516 528 -PMVL1 PML2 PMLII3 PM4PLWM6MN2PL-1-1PMLN EC(1) EC(2) EC(G) EC1)EC(2) EQ(G)

Description

SEction 29 Rcgumtion 2-A(-J) AUSTRALIA PuluJ its Au! 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Feedback signaling error detection and checking in MIMO wireless communication systems The following statement is a full description of this invention, including the best method of performing it known to us: P11 1AHAU/0710 1.0001] FEEDBACK SIGNALING ERROR DETECTION AND CHECKING IN MIMO WIRE LESS COMMUNICATION SYSTEMS [0002] FIELD OF INVENTION [0003] This application is related to wireless communications. [0004] BACKGROUND [0006] A goal of the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) program is to develop new technology, new architecture and new methods for settings and configurations in wireless communication systems in order to improve spectral efficiency, reduce latency and better utilize the radio resource to bring faster user experiences and richer applications and services to users with lower costs, [00061 Wireless communication systems usually require feedback signaling to enable uplink and downlink communications. For example, hybrid automatic retransmission request (HARQ) enablement requires acknowledge/non acknowledge (ACK/NACK) feedback. Adaptive modulation and coding (AMC) requires channel quality index (CQI) feedback from a receiver. Multiple Input/Multiple Output (MIMO) systems or preceding requires rank and/or preceding matrix Index (PMI) feedback from a receiver. Typically, this type of feedback signaling is protected by coding and the signaling does not have error checking or detection capabilities. However, efficient signaling i 5 essential to an evolved universal mobile telephone system (UMTS) terrestrial radio access network (E-UTRAN). Adding error check-(EC) and eror detection capability to the feedback control signaling makes more advanced applications possible. Error check (EC) and error detection capability can enable advanced signaling schemes, enhanced MIMO link performance, reduced system overhead, and increased system capacity. 10007] An example of an application that may require error detection and checking capability for feedback control signaling is the preceding information validation. The preceding information validation is used to inform a WTRU about -1the preceding information that is used at an e Node B so that the effective channel seen by the WTRU that contains preceding effects can be reconstructed by the WTRU. This is required for accurate data detection for MIMO systems using preceding, beamforming or the like. [0008] A wireless transmit receive unit (WTRU) may feedback a preceding matrix index (PMI) or antenna weight to a base station (BS) or an a Node B (eNB). To inform a WTRU of the precoding matrices used at an eNB, the eNB may send a validation message to the WTRU. Each matrix that the WTRU signals as feedback to the eNB may be denoted by PMIVjl, PMIj2 ... PMTJN, where N is a integer value equal to the total number of matrices. The eNB may send a validation message containing information about N PMIs denoted by PMI_k1, PMIk2.- - PMIkN to the WTRU. [0009) Each PMI may be represented by L bits. The value of L depends upon the multiple input/multiple output (MIMO) antenna configuration and codebook sizes. f0010] Communication resources may be assigned to a WTRU. A resource block (RB) consists of Mi subcarriers, for example M = 12, where M is a positive integer. A resource block group (RBG) or sub-band may include N_RB RBs, where N_RB may equal, for example, 2, 4, 5, 6, 10, 25 or larger. A system bandwidth can have one or more RBGs or sub-bands depending on the size of bandwidth and value of N_RIB per RBG or sub-band. [0011] A WTRU may feed back one PMI for each RBG or sub-band that is configured to it. The terms RBG and sub-band may be used interchangeably. N RBGs, where N c NRBG, can be configured to or selected by a WTRU for feedback and reporting purpose. If N RBGs or sub-hands are configured to or selected by a WTRU, then the WTRU feeds back N PMIs to the eNB- The eNB may send the validation message consisting of N PMIls back to the WTRU, [0012] Let N PMI be a number of bits that represents a PML The total number of bits for the WTRU PMI feedback is N x N _PML The maximum number of bits for WTRU PMI fbedback is N_RBG x N_PMI bits per feedback instance. When a straightforward preceding validation scheme is used, the -2maimum number of bits for PMI validation message is N_RBG N_PMI bits per validation message. [0013] Table 1 shows a number of bits for WTRU PMI feedback and signaling with the assumption that N_PMI = 5 bits. The numbers are sumnmarized for 5, 10 and 20 Mfz bandwidth. The second row, N_RB, is the number of RBs per RBG or sub-band, which is in a range of 2 to 100 for 20MHz. The third row, N_RBG per band, is the number of RBGs or sub-bands per 5, 10 or 20 MHz. The value of N_RBG is in a range from one to fifty. The fourth row is the total number of bits used for WTRU PMI feedback signaling per feedback instance. This is for frequency selective precoding feedback or multiple PMI fbedback [0014] 5 MIH 10 MHz 20MIz (300 sucrir) (600 suboarriers) (1200 suhearriers) 0 NRB per 2 5 | 10 25 2 5 10 25 50 2 5 10 25 50 100 RBG NRBG 13 5 3 1 25 10 5 2 1 50 2010 4 2 per band Max # of 65 25 15 5 125 I0 25 10 5 250 100 50 20 10 bits for PMI feedback per feedback Max#of 65 25 1 5 125 50 25 10 5 250 100 5020 0 5 bits for PMI signaling per message Assume 12 subcarriers per RB. N-RB: Number of resource blocks. NiRBG: Number of frequency R13 groups. N_PMI: Number of bits to represent a PMI, Max number of bits for WTRUPMI feedback =NJG x NJ'AM bits. Max number of bits for eNB validation message = NB_G x NYMC bits. Table 1. Maximum number of bits for PMI feedback and PMI validation -3- 4 [0015] PMI feedback and PMI validation may require over 250 bits per feedback instance and per validation message as shown in the above table. [0016] Feedback error significantly degrades the link and system performance. It would be desirable for feedback bits to be protected with error checking (e.g., channel coding). Furthermore, knowing whether there is an error in a feedback signal improves system performance such as link performance, because the erroneous feedback information can be avoided. Furthermore, knowing whether there is error in the feedback signaling enables the use of advanced signaling schemes or applications such as the precoding confirmation and indication schemes. Precoding confirmation can be sent to confirm the correctness of feedback signaling if there is no error in the feedback signaling. [0017] A single bit or bit sequence may be used for precoding confirmation and may be sufficient for some applications. The use of advanced signaling such as precoding validation using confirmation significantly reduces the signaling overhead. Therefore error checking and detection is desirable. SUMMARY [0016] Disclosed is a method and apparatus for feedback type signaling error check, detection and protection in a wireless communication system. Feedback type signaling may include channel quality index (CQI), precoding matrix index (PM I), rank and/or acknowledge/non-acknowledge (ACK/NACK). The disclosure includes a wireless transmit receive unit (WTRU) performing a method that includes providing a PMI(s), producing error check (EC) bit(s), coding the PMI(s) and the EC bit(s), and transmitting the coded PMI(s) and EC bit(s). The method may be applied to other feedback information, such as CQI, rank, ACK/NACK and the like. [0017] In one aspect the present invention provides a method of feedback in a wireless transmit receive unit (WTRU), the method including: the WTRU generating a feedback signal, the feedback signal including at least one of a precoding matrix index (PMI) or a channel quality index (CQI); the WTRU determining a number of bits of the feedback signal to be encoded; the WTRU selecting a type of error detection and correction scheme to apply to the feedback signal based on the number of bits of the feedback signal to 4a be encoded, wherein selecting the type of error detection and correction scheme includes selecting a number of error check (EC) bits to attach to the feedback signal and selecting a type of channel coding scheme to apply to the feedback signal and the selected number of EC bits; the WTRU encoding the feedback signal and the selected number of EC bits using the selected type of channel coding scheme; and the WTRU transmitting the encoded feedback signal. [0018] In another aspect the present invention provides a wireless transmit receive unit (WTRU) including a processor configured, at least in part, to: generate a feedback signal, the feedback signal including at least one of a precoding matrix index (PMI) or a channel quality index (CQI); determine a number of bits of the feedback signal to be encoded; select a type of error detection and correction scheme to apply to the feedback signal based on the number of bits of the feedback signal to be encoded, wherein the processor is configured to select the type of error detection and correction scheme by selecting a number of error check (EC) bits to attach to the feedback signal and by selecting a type of channel coding scheme to apply to the feedback signal and the selected number of EC bits; encode the feedback signal and the selected number of EC bits using the selected type of channel coding scheme; and transmit the encoded feedback signal. [0019] In a further aspect the present invention provides a method for a wireless transmit receive unit (WTRU), the method including: the WTRU determining to transmit a first feedback signal in a first transmission time interval (TTI), wherein the first feedback signal includes a first group of precoding matrix indices (PMIs); the WTRU selecting a first type of error detection and correction scheme to apply to the first feedback signal based on a number of bits of the first feedback signal to be encoded, wherein selecting the first type of error detection and correction scheme to apply to the first feedback signal includes selecting a number of cyclic redundancy check (CRC) bits to attach to the first feedback signal and selecting a type of channel coding scheme to apply to the first feedback signal and the selected number of CRC bits; 4b the WTRU applying the first type of error detection and correction scheme to the first feedback signal; the WTRU transmitting the encoded first feedback signal in the first TTI after applying the first type of error detection and correction scheme; the WTRU determining to transmit a second feedback signal in a second TTI, wherein the second feedback signal includes a second group of precoding matrix indices (PMIs); the WTRU selecting a second type of error detection and correction scheme to apply to the second feedback signal based on a number of bits of the second feedback signal to be encoded; the WTRU applying the second type of error detection and correction scheme to the second feedback signal; and the WTRU transmitting the encoded second feedback signal in the second TTI after applying the second type of error detection and correction scheme. [0020] In yet another aspect the present provides a wireless transmit receive unit (WTRU) including a processor configured, at least in part, to: generate a feedback signal, the feedback signal including at least one of a precoding matrix index (PMI) or a channel quality index (CQI); determine a number of bits of the feedback signal to be encoded; select a number of error check (EC) bits to attach to the feedback signal based on the number of bits of the feedback signal to be encoded; selecting a type of channel coding scheme to apply to the feedback signal and the selected number of EC bits based on the number of bits of the feedback signal to be encoded; encode the feedback signal and the selected number of EC bits using the selected type of channel coding scheme; and transmit the encoded feedback signal. BRIEF DESCRIPTION OF THE DRAWINGS [0021] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings wherein: [00221 Figure 1 shows a wireless communications system including a plurality of WTRUs and an eNB; [0023] Figurc 2 is h ftinctional block diagram of the WTRU and the eNB of the wireless communication system of Figure 1; [0024] Figure 3 is a block diagram of PMI feedback with error checking and correction in accordance with one embodiment; [0025] Figure 4 is a block diagram of PMI feedback with error checking and correction in accordance with another embodiment; [0026] Figure 5 is a block diagram of PMI feedback with error checking and correction in accordance with an alternative embodiment; [0027] Figure 6 is a block diagram of PMI feedback with error checking and correction in accordance with another alternative embodiment; 100281 Figure 7 is a block diagram of PMI feedback with error checking and correction in accordance with yet another alternative embodiment; [0029] Figure 8 is a block diagram of PMI feedback with error checking and correction in accordance with yet another alternative embodiment; [0030] Figure 9 is a block diagram of PMI and CQI fbedback with error checking and correction in accordance with yet another alternative enabodiment; [0031] Figure 10 is a block diagram of PMI and CQI feedback with error checking and correction in accordance with yet another alternative embodiment; [0032] Figure 11 is a block diagram of PML, OQI and ACK/NACK feedback with error checking and correction in accordance with yet another embodiment; and [0033] Figure 12 is a block diagram of PMI, CQI and ACK/NACK feedback with error checking and correction in accordance with yet another embodiment. [0034] DETAILED DESCRIPTION 10035] When referred to hereafter, the terminology "wireless transmit/receive unit CWTRUy includes but is not limited to a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a cellular -5telephone, a personal digital assistant (PDA), a computer, or any other type of user device capable of operating in a wireless environment. When referred to hereafter, the terminology "base station" includes but is not limited to a Node-B, a site controller, an access point (AP), or any other type of interfacing device capable of operating in a wireless environment. 100361 Figure 1 shows a wireless communication system 100 including a plurality of WTRUs 110 and an eNB 120. As shown in Figure 1, the WTRUs 110 are in communication with the eNB 120. Although three WTRUs 110 and one eNB 120 are shown in Figure 1, it should be noted that any combination of wireless and wired devices may be included in the wireless communication system 100, [0037] Figure 2 is a functional block diagram 200 ofthe WTRU 110 and the eNB 120 of the wireless communication system 100 of Figure 1. As shown in Figure 2, the WTRU 110 is in communication with the eNB 120. The WTRU 110 is configured to transmit feedback signals and control signals to the eNB 120. The WTRU is also configured to receive and transmit feedback and control signals from and to the eNB. Both the eNB and the WTRU are configured to process signals that are modulated and coded. [0038 In addition to the components that may be found in a typical WTRU, the WTRU 110 includes a processor 215, a receiver 216, a transmitter 217, and an antenna 218. The receiver 216 and the transmitter 217 are in communication with the processor 215. The antenna 218 is in communication with both the receiver 216 and the transmitter 217 to facilitate the transmission and reception of wireless data. [0039] In addition to the components that may be found in a typical eNB, the eNB 120 includes a processor 225, a receiver 226, a transmitter 227, and an antenna 228. The receiver 226 and the transmitter 227 are in communication with the processor 225, The antenna 228 is in communication with both the receiver 226 and the transmitter 227 to facilitate the transmission and reception of wireless data, -6- 10040) A WTRU may transmit a feedback signal (e.g., PMI feedback) to an eNB. Error check (EC) (e.g., Cyclic Redundancy Check (CRC)) bits may be attached to the feedback signal (e.g., PMI feedback). Both the feedback signal (e.g., PMI) and the EC bits may be encoded prior to transmission. The feedback signal may include PMI, CQI, rank, ACK/NACK or other type feedback signal. While this disclosure makes reference to a PMI bit, CQI bit, EC bit and the like, one skilled in the art may recognize that PMI feedback, CQI feedback and error checking and correction may be, and in most cases is multiple bits. Although feedback signasl such as PMI or CQI are used as examples other type feedback signals may also be used.. {0041] Different type channels may be used for transmitting and carrying the feedback type signal. For example, both control type channels and data type channels may be used to carry the feedback type signal. An example of a control type channel is the physical uplink control channel (PUCCH). An example of a data type channel is the physical uplink shared channel (PUSCH). However, one skilled in art will recognize that the method and apparatus disclosed herein are independent of channel choice. [00421 The PIVU and EC bits may be coded together, with or without data bits. Both data type channels and control type channels may be used to transmit the feedback signal and EC bits. For example a data type channel (e.g., the physical uplink shared channel (PUSCH)) may be used to transmit PMI and EC bits. A control type channel (e.g., the physical uplink control channel (PUCCH)) may also be used to transmit PMI and EC bits. {0043] Alternatively, PMI1 and EC bits may be coded with a first coding scheme and data bits may be coded with a second coding scheme. Each of the coding schemes may be different. For example, convolutional coding or Reed Muller coding maybe used for the feedback type signal and while turbo codingis used for the data type signal. Alternatively, the coding schemes may be the same, but with different parameters and settings to address different error rate requirements for feedback type signal and data type signal. The data type -7cl-uuwl (e., PU UH) may be used to transmit PMI and EC bits, The control type Ilmtunel (e.g., PUUUH) may also be used to transmit PMI and EC bits. [0044] PMI and BC bits may be separately coded for each group, if grouping is used for feedback type signaling. [0045] All the PMI and/or EC bits may be fed back or reported at the same time For example, all the PMI and/or BC bits may be reported in a same transmission time interval (TTI). Alternatively, the feedback type bits and the error checking bits may be reported at a different time. For example, PMI and/or EC bits may be split into groups and reported in different TTIs. [0046] Error checking and detection methods such as cyclic redundancy check (CRC), for example, may be used. If CRC is used, it may be, for example, 24-bit CRC or 16-bit CRC, The length of the CRC may be varied, and the actual length used may depend on design choices. [0047] CRC bits may be attached to feedback type signals and transmitted on a data type channel to carry the feedback type signal bits and CRC bits. The feedback type signals may be, for example, PMI, CQI, rank or ACKINACK, The data type channel nay be, for example, a PUSCH. A data type channel has a large capacity and can accommodate a relatively large number of bits. Therefore, the CRC can be, fBor example, 24-bit CRC, 16-bit CRC or some other length CRC. Long CRC may be used, and is preferable as it provides for better error checking. While this may add additional overhead due to the addition of CRC bits, the PUSCH may have the capacity to handle the larger number of bits. Using a data channel, such as PUSCH, allows for the transmission of feedback signals such as PMI, CQI, rank and ACK/NACK in a single TTIL Therefore, a feedback type signal with a long CRC that provides better error check capability can be implemented. [0048] Alternatively, CRC bits may be attached to feedback type signals and transmitted on a control type channel. The CRC can be a 24-bit CRC, 16-bit CRC or other length CRC. Typically, control type channels may not have large capacity to carry a large number of bits, In order to transmit CRC bits and the feedback type signals, the transmission may be split and transmitted multiple -8trmos, The PMI feedback signal may be split, amd transmitted in multiple 'TTis. For exnmpl 1 ne PMI may be tonnmtAd -n r.-1 'rPT -tnL ani the tAiAI5a&t signals are transmitted. CQI or other feedback signals can be handled in a similar way. [0049] PM, CQT and/or other feedback type signals can be transmitted separately at different times or in different TTIs. In general, a control type channel (e.g. PUCCH) may not carry large number of bits each time and if there are large number of feedback bits needed to be sent, the feedback bits can be divided or split into groups. Each group may be reported, one at a time. Each feedback instance may contain a single PMI, CQI, other feedback signal, or combination of feedback signals. The CRC can be fed back or transmitted at the same time (in the same TTI) as PMI or CQI. Alternatively, the CRC can be fed back or transmitted separately from PMI or CQL That is, CRC can be transmitted at diffeTrent times or in different TTIs from the times or TTIs that the PMI or CQI are transmitted. CRC can also be divided into segments or groups, and each CRC segment may be transmitted or fed back with feedback signal at the same time or in the same TT. Each CRC segment can also be transmitted at different time or different TTL [00501 Use of ORC attached to the feedback signal can apply to a single feedback signal such as one PMI and/or one CQ. Such single feedback scheme may be used when non-frequency selective feedback or widebaud feedback (one feedback per entire bandwidth or per entire configured bandwidth) is used. [0051] Other error check or detection methods such as parity check (including a single-bit parity check) or a block parity check, for example, may also be used. The disclosure herein is not limited to any one particular error checking scheme, as would be recognized by one skilled in the art. [0052] Coding schemes such as convolutional coding, Reed-Solomon or Reed-Muller coding, for example, may be used. Other coding schemes, for example, turbo coding and low density parity check (LDPO) code, may also be considered. If the feedback is transmitted via a data type channel (e.g., physical uplink shared channel (PUSCH)), convolutional or block coding may be suitable -9because the data type channel (e.g., PUSCH) allows transmission of a large number of bits. Reed-Muller or Reed-Solomon coding also may be suitable due to a moderate number of bits being coded by these coding schemes. The disclosure herein is not limited to nrny nne particular coding ,;Lmue, as would be recognized by one skilled in the art. [0053] Figure 3 is a block diagram 300 of PMI feedback with error checking and correction in accordance with one embodiment. Multiple PMIs configured as PM1_1 302, PMI2 304, PMI_3 306 through PMIN-1 308 and PMIN 310 are shown in Figure 3. EC bits 312 are attached to the PMI signal 316. The EC bits 312 could be CRC bits of 24 bit length, 20 bit length or 16 bit length. Other lengths of CRC may also be used. PMI bits (302-310) and the EC bits 312 are encoded by a channel coding function 314 prior to transmission. The channel coding can be performed jointly for all PMIs and EC. The jointly encoded PMIs and EC can be transmitted at the same time or in the same TT. The jointly encoded PMfs and EC can be transmitted at a different time or in different TTIs. Alternatively the channel coding can be performed separately for each PMI and the EC bits or for a group of PMIs and BC. The EC bits can be divided into segments and each EC bit segment can be separately channel encoded and transmitted. [00541 For example if there are an integer number "N" PMIs, each PM may be 4 bits and each EC may be 24 bits, using, for example, 24 bit CRC. The total number of bits is 4N+24 bits. The total number of bits can be jointly encoded using channel coding (e.g., convolutional coding). The encoded bits can be transmitted or fed back at one time in a single TTI. The total number of encoded bits can also be transmitted or fed back at several different time, or different TTIs. For example, the encoded bits may be transmitted an integer number "U" times in M different TTIs. Each TTI may transmit (4N+24)/M original information and CRC bits. The (4N+24)/M original information and CRC bits in each TTI may contain PMT bits and/or CRC bits. If the TTI contains a combination of PMI and CRC bits, then 4N/M PMI bits and 24/M CRC bits may -10be included in a single TTI. If M-N, 4 PMI bits and a fractional portion of the CRC bits may be tramittrfl.p1l in % dingio TTL [0055] Alternatively, a 24 bit CRC can be divided into 6 segments, each with 4 bits, which is the same number of bits as in a PMJ. Each PMI and each CRC segment may be separately or jointly encoded and transmitted in a TTI. [00561 The BC bits 312 can be a CRC, for example, The channel coding function 314 can be convolution coding, for example. Error checking and detection methods, such as a parity check, can also be used, and other channel coding methods, such as Reed-Muller coding or Reed-Solomon coding, for example, can also be used. [0057] Each PMI may represent preceding information for a sub-band, an RBG, a group of sob-bands or a wideband. For example, PMI_1 can be a wideband PMI ("average" preceding information for a whole band) and PMI_2 to PMIN can be sub-band PMIs or averaged PMIs, each corresponding to a preceding information for a sub-band, and RBG, or a group of sub-bands. [0058] Similarly CQI and other feedback type signals can be added with error check capability by attaching CRC, channel coded and transmitted as described previously. [00591 PMI feedback signaling may be combined into groups with separate error checking for each group of PMIs. EC bits may be attached to each group of PMIs before channel coding. [0060] Figure 4 is a block diagram 400 of PMI feedback with error checking and correction in accordance with another embodiment, where PMI_1402, PMI_2 404 and PMI_3 406 are grouped together and a first error check EC(1) 408 is attached. PM4 410, PML5 412 and PMIL6 414 are grouped together and are attached with EC(2) 416. PMEN-2 418, PMI_N-1 420 and PMIN 422 are grouped together and are attached with EC(G) 424. PMI (402-406, 410-414,418 422) and EC 408, 416, 424 are coded by channel coding function 426. [0061] As state above, the EC could be a CRC. An error checking, detection and correction method may be selected based on a total number of bits that are encoded. The RC may use, for example, a short or long CRC, a single parity bit -11or a black pnrity chock bit. Othlerv f checking, correction and detection methods, such as advanced parity checking, for example, may be used. [0062) The channel coding function may use, for example, convolutional coding or Reed-Solomon coding. Other channel coding methods, such as block coding, turbo coding or LDPC, for example, may also be used. [0063] PMIs can be divided into several groups and groups of PMIs can be transmitted in different transmission time intervals (TTI). Groups of PMIs may also be transmitted in a single TTI. Each group may be reported after channel coding. This is referred to as frequency selective feedback and reporting of multiple PMIs, CQL rank and ACKJNACK signals may also be fed back or reported on a frequency selective basis. [0064] PMI1 402, PMI_2 404, PMI3 406 and EC(1) 408 maybe reported in a single TT, for example TTI(1). PMl44 410, PML5 412, PMI6 414 and EC(2) 416 may be reported in a second TTI, for example TTI(2). PMLWN-2 418, PMIN-1 420, PMIN 422 and EC(G) 424 may be reported in another TTI, for example TTI(G). [0065] If the error detection or checking mechanism is disabled or if the error detection or checking capability is removed, there is no EC bit attachment. In that case, PMI group 1 (PMI1 402, PMI 2 404, PML3 406) may be reported in TTI(1), PMI group 2 (PMI4 4 10, PML5 412, PM16 414) may be reported in TTI(2) and PMI group G (PMIN-2 418, PMLN-1 420, PMIJN 422) may be reported in TTI(G). The reporting may occur with or without EC bits. [00661 Figure 5 is a block diagram of PMI feedback with error check and correction in accordance with an alternative embodiment. The error check bits EC(1) 508 are used for PMI_1 502, PMI_2 504 and PML3 506. The error check bits EG(2) 516 are used for PMIL4 510, PMI 512 and PMI6 514 and the error check bits EC(G) 528 are used for PMIN-2 522, PML N-1 524 and PMIN 526. The PMI bits and the EC bits are coded by channel coding function 540 prior to transmission. [0067] In another alternative embodiment, the PIs may be separated into groups, and each group has an associated error detection and check value. The -12feedback signaling and error check of each group are coded separately. The coded feedback bits and EC bits can be transmitted in the same TTI or in different TTIs. Each PM group, with itssmneiated RC, ic coded individually. [0068] Figure 6 is a block diagram 600 of PMI feedback with error check and correction in accordance with the other alternative embodiment. PMIs are divided into G groups for error detection and/or correction. EC.) 620 is attached to PMI_1 602, PMI_2 604 and PMI_3 606, EC(2) 622 is attached to PML4 608, PMI5 610 and PMI6 612 and EC(N) 624 is attached to PMEINT-2 614, PMI.-I 616 and PMLN 618. PMI 602, PMIA2 604 and PMI_3 606 and BC (1) 620 are encoded by a first channel coding function 630. PMIL4 612, PMI15 614 and PMl6 616, along with E0(2) 622 are encoded by second channel coding function 640. PMIN-2 614, PMIN-1 616 and PMIN 61.8, along with EC(G) 824 are encoded by an Gth channel coding function 650. Error checking, correction and detection methods may be chosen based on the number of bits requiring encoding. The EC may use, for example, a CRC that may be, for example, 24 bits, 20 bits or 16 bits. The EC may also use a single parity bit or block parity check bits that have fewer bits than 16 bits. The EC may also use, for example, error checking and detection methods such as advanced parity check. [0069] The channel coding functions 630, 640, 650 may use, for example, convolutional coding or Reed-Solomon coding. Other appropriate channel coding such as block coding, turbo coding or LDPC may also be used. [0070] The BC bits can be divided into several groups, each group of EC bits can be fed back or reported at the same time or at different time. For example each group of EC bits can be fed back or reported in the same or different TTIs. Each group is reported after joint or separate channel coding for each group. [0071] Each PMI group can be reported in a different TTI or together in the same TTIl. Each group is reported after separate channel coding of groups. Also, other feedback signaling, such as CQ, rank, and ACK/NACK, for example, may be used. -13- [00721 PMI_1 602, PML2 604, PMLS 606 and EC(1) 620 may be reported in TTI(1). PMI34, PMG PMIJ and ElC(z) may be reported in TTI(2), and PMIN-2 , PMIN- I, PMIN and EC(G) may be reported in TTI say TTI(G), [00731 If the error detection or check mechanism is disabled or if error detection or check capability is removed, there may be no EC bits attachment, The PMI groups may then be reported without the EC bits. PMI group 1 (PMI1i 402, PML2 404, PMI-3 406) may be reported in a TTI(1), PM1 group 2 (PMI_4 410, PMI5 412, PMI6 414) may be reported in TTI(2) and PM1 group G (PMIN-2 418, PMIN-1 420, PMI$ 422) may be reported in TTI(G). Each reporting group may have separate channel coding. [0074] When the number of PMVIT groups is equal to the number of PMIs (G=N), then there is one PMI per each PM1 group. Each PMI may be attached with EC (e.g., CRC) bits and encoded separately. Each PMI may be reported at different times. PIM_1 702, PMI_2 704 and PMLN 706 may be reported in different TIs. For example, PMI_1 702 may be reported in TTI(l), PMI_-2 704 in TTI(2) and PMIN 706 in TTI(N.). The feedback or reporting may occur via a control type channel (e.g., physical uplink control channel (PUCCH)). [00751 Alternatively, PMI_ 1 704, PMI_2 70, PMIN 706 may be reported at the same time. For example PMI_1 704 to PMTN 706 may be reported in a single TTI. This may occur via the data type channel (e.g., PUSCH), due the ability of the data type channel (e.g., PUSCH) to handle more bits. Other feedback signals, such as CQ, rank, and ACK/NACK, for example, may be used with or instead of PMI. [0076] Figure 7 is a block diagram of PMI feedback with error checking and correction in accordance with yet another alternative embodiment. PMIs are divided into G groups for error check and detection, with G-N. PML1 702 is attached with error check bits EC(1) 712, PTMI2 704 is attached with EC(2) 714 and PMIJN 706 are attached with EG(N) 716. Each PMI/EC pair is encoded by the channel coding function 720. Appropriate error checking, correction and error detection schemes may be used, and may depend on the number of bits required to be encoded. For example, a particular EC may use a CRC, for -14example, 24-bit CRC, short CRC, a single parity bit or block parity check bits. Chmannel mding may ten Rood Soiomon codin%, fur ample. Other appropriate error check and detection such as long CRC or other parity check schemes may be used. Other appropriate channel coding such as block coding, convolutional coding, turbo coding or LDPC may also be use. [0077] Using frequency selective reporting, PMI1 702 may be reported in TTI(1), PML2 704 in TTI(2) and PMEN 706 in TTI(N). These PMIs may be reported via the control type channel (e.g., PUCCH). Alternatively, PMLI to PMIJN can be reported in a single TTI via the data type channel (e.g., PUS CH). Other feedback signaling, such as CQI, rank and ACK/NACK, for example, may be used. [0078] Figure 8 is a block diagram of PMI feedback with error checking and correction in accordance with yet another alternative embodiment. EC(l) 812 may be used for PMI1 802, EC(2) 814 may be used for PMI2 (804) and EC(N) 816 may be used for PMIN (806). PMIs and ECs are coded either separately or jointly in the channel coding function 820. {0079 PMIJ 802 may be reported in TTI(i), PMI_2 804 may be reported in TTII(2) and PMI(N) 806 may be reported in TTI(N). PML1 802, PML2 804 and PMLN 806 can be separately coded and reported in different or the same TIs. Alternatively PML1 802 PMJ2 804, and PMIN 806 can be jointly coded, split, and reported in different TTIs. Furthermore PML1 802, PMI_2 804 and PMIN 806 can be jointly coded and reporLed in the same TTL Alternatively, PMI1 802, PM12 804 and PMIN 806 can be separately coded with different protection schemes and reported in the same TTI. CQI, rank and ACI/NACK may be used as well. [0080] Figures 3 to 8 depict error checking, coding and feedback for PMI, and show a single type feedback signal. CQI and other type feedback signals can be substituted for PMI. [0081 Figures 9 through 12 depict error checking, coding, transmission and feedback for more than one type feedback signal. Figures 9 through 12 are discussed in detail below. -15- [0082] PMI feedback and other type control signaling may be error checked separately with the same or different error checking and then encoded together, For example, a first type feedback signal, which may be a PMI, can be attached with a first EC, which may be a CRC, such as a 24 bit CRC. A second type feedback signal, which may be a CQI, may be attached with the same C. [0083 in another example, a first type feedback signal, which may be a PMI, may be attached with an EC, which may be a CRC, such as a 24 bit CRC. A second type feedback signal may be attached with a second EC, may be a 16 bit CRC. [0084] In general, difbrent error checking and/or correction can be used fbr different types feedback signals or different feedback signals of the same type, The choice of which error checking and/or correction to uso may involve a design decision of robustness versus overhead, A longer CRC may give greater protection, but it also creates more bits. Therefore, if one type feedback signal is more important than another type feedback signal, a stronger error checking and/or correction capability can be provided to the more important type feedback signal. Similarly for the feedback signal of the same type if one feedback signal or group of feedback signals is more important than another foodback signal or group of feedback signals, a stronger error checking and/or correction capability can be provided to the more important feedback signal or group of feedback signals. [0085] Referring again to the examples provided above, if the first feedback signal, which may be PMI, is more important than the second feedback signal, which may be a CQI, then a longer CRC with higher error check and detection ability can be used for PMI and shorter CRC with lower error check and detection ability can be used for CQ. [0086] Applying different error checking and/or correction capabilities to feedback signals can protect the feedback signal that are of importance, optimize the link performance and minimize the signaling overhead. [00871 Figure 9 is a block diagram 900 of PMI feedback with error checking and correction and channel quality index (CQI) feedback with error checking and -16correction in accordance with yet another alternative embodiment. A first EC 930 (e.g., CRC) is attached to PML1, 902 PML_2 904, PMI_3 906 through PMIN 908, A second EC 940 (e.g., CRC) is attached to CQI-1 912 through CQI-M 914. The EC attached PMI signal 910 and the CQI signal 920 are coded together in the channel coding function 950 to produce a single transmit signal. [0088] In Figure 9 the first EC 930 and the second EC 940 may be the same. This would give equal error checking and protection to each feedback signal. [00891 Alternatively, the first EC 930 and the second EQ 940 may be different. If the PMI feedback is more important to system performance than the CQI feedback, the first EC 930 may be more robust. For example, the first EQ may be a 24-bit CRC and the second EQ may be a 16-bit CRC. [00901 PMI feedback signals can consist of a "wideband" PMI, "narrowband" PMI", "sub-band" PMI, and/or averaged PML Similarly CQI feedback signals can consists of a "wideband" CQ, "narrowband" CQI, "sub-band" CQI and/or averaged CQI, Also, similar to the embodiments including a single feedback, as shown in Figure 3 through Figure 8, the EC bits and the feedback bits may be transmitted in a single TTI, or may be split in to multiple TTIs, More specifically, the data type channels (e.g., PUSCH) may be used to transmit the feedback bits and the EC bits in a single TTI, as the data type channel is able to handle a greater number of bits per TTI. [00913 Also, the coding used for the feedback bits and the EC bits may be the same with the same or different weights, or may be different. One skilled in the art would recognize that there numerous possible combinations of coding, transmitting, and error checking. [0092] Figure 10 is a block diagram 1000 of PMI and CQI feedback in accordance with yet another embodiment. The feedback signals may be attached with error check bits together and coded together. Signals that include PMI_1 1002 through PMT N 1004 are input into an EC attachment/insertion function 1020 along with signals that include CQJ_ 1012 through CQI._M 1014. The -17signals are processed by the EC function 1020 and a single output signal is input into a channel coding function 1030 prior to trasnmission. [0093] Control signaling other than CQI may be used as well, including rankz and AUlNACK. [0094] Figure 11 is a block diagram 1100 of PMI feedback with error checking and correction, CQI feedback with error checking and correction and ACKJNACK feedback in accordance with yet another embodiment. A first EC 1110 is attached to PMI_1 1102 through PMILJN 1104. A second EC 1120 is attached to CQI1 1112 through CQIjM 1114. The PMI signal 1106 and the OQI signal 1116 are inpnt into a channel coding function 1140 with an AKJ/NACK( signal 1130. [0095] ACKINACK feedback signal 1130 can be replaced with rank feedback signal in Figure 12. Alternatively rank feedback signal can be added to Figure 12. [0096] Figure 12 is a block diagram 1200 of PMI feedback and CQI feedback with ACK/NACK feedback in accordance with yet another embodiment, CQI, PMI and ACK/NACK may be coded together, but error checked separately. A PM signal 1202 including PMI 1 1204 through PMI_N 1206, a CQI signal 1212 including CQI 1214 through CQLM 1216 and an ACK/NACKsignal 1220 are input into an EC attacbment/insertion function 1230. The single signal output is processed by a channel coding function 1240 and transmitted. One EC (e.g., CRC) is attached to the combined signal prior to coding and transmission. [0097] ACK/NACK feedback signal 1220 can be replaced with rank feedback signal in Figure 12. Alternatively rank feedback signal can be added to Figure 12. [0098] The PMI, CQI and ACINACK signals may have different error checking and/or protection. For example PM may have the highest error checking and/or error protection, while CQI may have lower error checking and/or error protection. PMI, CQI, and ACK/NACK can have different error checking and/or protection while using different error checking and/or coding schemes or using the same error checking and/or coding scheme. Different -18weights may be used on, PMI, CQI and ACK/NACK signals. The different error checking and/or error protection may be achieved by using different error checking and/or coding schemes, or using the same error checking and/or coding s cheme but with different importance weights on different feedback type signals by using unequal error checking and/or coding and protection schemes. This may be applicable to other feedback signaling, such as rank, for example. [0099] Similarly PMI feedback signals can consist of a "wideband" PMI, "narrowband" PMI", "sub-band" PMI and/or averaged PMI. Similarly CQI feedback signals can consists of a "widoband" CQI, "narrowband" CQI, "sub-band" CQI and/or averaged OQI. [00100] EMBODIMENTS [00101] 1. A method of feedback in a wireless transmit receive unit (WTRU), the method comprising providing a pr coding matrix index (PMI);error checking the PMI to produce an error check (EC) bit; coding the PMI and the BC bit; and transmitting the coded PMI and EC bit. [00102] 2. The method as in embodiment 1 finther comprising grouping a plurality of PMIs into PMI groups. [00103] 3, The method as in embodiment 1 or 2 further comprising error checking each of the plurality of PIV groups to produce the EQ bit. [00104] 4. The method as in any one of embodiments 2 or 3 further comprising error checking each of the plurality of PMI groups to produce a plurality of EQ bits, wherein one of the plurality of EC bits is attached to each PMI group; an coding the attached EU bit with the corresponding PMI group. [001051 5. The method as in any one of embodiments 2-4 further comprising error checking each of the plurality of PMI groups to produce a plurality of EC bits, wherein one of the plurality of EC bits is attached to each PMI group; and coding the E C bits after coding the PMI groups. [00106] 6. The method as in embodiment 4 or 5 further comprising providing a plurality of coding functions, wherein each of the plurality of coding functions is associated with one of the plurality ofPMI groups; and coding each of -19the plurality of PMI groups and associated EC bits with an associated coding function. [001071 7. The method as in any one of embodiments 3-6 wherein a number of PMI groups is equal to a number of EC bits. [001081 8. The niethod as in any one of embodiments 3-7 further comprising error checking each PMI group individually; and coding the plurality of PMI groups with the EC bits. 100109] 9. The method as in any one of embodiment 3-8 further comprising error checking each PMI group individually, and coding the plurality of PMI groups separately from the EC bits. [00110] 10. The method as in any one of embodiments 1-9 further comprising providing a control index; error checking the control index to produce a second EC bit; and coding the PMI and the RC bit with the control index and the second EC bit. [00111] 11. The method as in embodiment 10 further comprising providing a error detection signal; and coding the PMI, the control index, the E Q bit, the second EC bit and the error detection signal. [001.12] 12, The method as in embodiment 11 wherein the error detection signal is an acknowledge/non-acknowledge (ACK/NACK) signal. [00113] 13. A method for feedback in a wireless transmit receive unit (WTLT), the method comprising providing a precoding matrix index (PMI); providing a control index; error checking the PMI and the control index to produce an error checking (EC) bit; and coding the PMI, the control index and EC bit. [00114] 14. The method as in embodiment 13 farther comprising transmitting the coded PMI, control index and EC bit to a base station. [00115] 15, The method as in embodiment 13 or 14 wherein the control index is a channel quality index (CQI). [00116] 16. A wireless transmit/receive unit (WTRU) comprising a processor configured to determine a preceding matrix index (PMI); error check -20the (PMT) tn nrnlwa @n mrrnr ohoc (r'C) '; an - 1,v rr uMB the 'Dir; and a transmitter configured to transmit the coded PMI and EC bit. [001171 17. The W'TtRU as in embodiment 16 wherein the processor is further configured to group a plurality of PMIs into PMI groups. 100118] 18. The WTRU as in embodiment 17 wherein the processor is further configured to error check each of the plurality of PMI groups to produce the EC bit. [00119] 19. The WT7RU as in embodiment 17 or 18 wherein the processor is further configured to error check each of the plurality of PMI groups to produce a plurality of EC bits, wherein one of the plurality of EC bits is attached to each PMI group; and code the attached EC bit with the corresponding PMI group. [00120] 20. The WTRU as in any one of embodiments 17-19 wherein the processor is further configured to error check each of the plurality of PMI groups to produce a plurality of EC bits, wherein one of the plurality of EC bits is attached to each PMI group; and code the EC bits after coding the PMI groups 100121] 21. The WTRU as in embodiment 20 or 21 wherein the processor is further configured to determine a plurality of coding functions, wherein each of the plurality of coding functions is associated with one of the plurality of PM4I groups; and code each of the plurality of PMI groups and associated EX bits with an associated coding function. [00122] 22. The WTRU as in any one of embodiments 19-21 wherein a nuTber of PMI groups is equal to a number of EC bits. [00123] 23, The WTRU as in any one of embodiments 19-22 wherein the processor is further configured to error check each PMI group individually; and code the plurality of PMI groups with the EC bits. [00124] 24. The WTRU as in any one of embodiments 19-23 wherein the processor is further configured to error check each PMI group individually, and code the plurality of PMI groups separately from the EC bits. [00125] 25. The WTRU as in any one of embodiments 16-23 wherein the processor is further configured to determine a control index; error check the -2]control index to produce a second EC bit; and code the PMI and the EC bit with the control indx and teb second EC bit. [00126] 26. The WTRU as in embodiment 25 wherein the processor is further cQfigured in AAPraring a error detection signl, and code the pIv11, the control index, the EC bit, the second EC bit and the error detection signal, [00127] 27. The WTRU as in embodiment 25 or 26 wherein the error detection signal is an acknowledge/non-acknowledge (ACK/NACK) signal [00128] 28. A method of feedback in a wireless transmit receive unit (WTRU), the method comprising providing a feedback bit error checking the feedback bit to produce an error check (EC) bit coding the feedback bit and the BC bit and transmitting the coded feedback bit and E C bit. [00129] 29. The method as in embodiment 28 further comprising grouping a plurality of feedback bits into feedback groups, 100130] 30. The method as in embodiment 28 or 29 further comprising error checking each of the plurality of feedback groups to produce the EC bit. [00131] 31, The method as in any one of embodiments 28-80 wherein the feedback bit comprises a precoding matrix index (PMI). [00132] 32. The method as in any one of embodiments 28-31 wherein the feedback bit comprises a channel quality index (CQI). [00133] 33. The method as in any one of embodiments 28-32 wherein the feedback bit comprises a rank, [00134] 34. The method as in any one of embodiments 28-33 wherein the feedback bit comprises anacknowledge/non-acknowledge (ACK/NACM. [00135] 35. The method as in any one of embodiments 28-34 wherein the BC bit comprises a cyclic redundancy check (CRC). [00136] 36. The method as in any one of embodiments 28-35 further comprising coding the EC bit with the feedback bit. (00137] 37. The method as in any one of embodiments 28-36 further comprising coding the RC bit separate from the EC bit, -22- 9 [00138] 38. The method as in any one of embodiments 28-37 further comprising transmitting the feedback bit and the EC bit in a single transmission time int(ITval (TTU) [001391 39. The method as in any one of embodiments 28-38 further comprising transmitting the feedback bit and the EC bit in separate TTIs. [00140) 40. The method as in any one of embodiments 28-39 further comprising transmitting the feedback bit and a portion of the EC bit in a single TTI. [00141] 41. The method as in any one of embodiments 29-40 further comprising error checking each of the plurality of feedback groups to produce a plurality of EC bits, wherein one of the plurality of EC bits is attached to each feedback group; and coding the EC bits after coding the feedback groups. [00142] 42. The method as in embodiment 41 further comprising providing a plurality of coding functions, wherein each of the plurality of coding functions is associated with one of the plurality of feedback groups; and coding each of the plurality of the feedback groups and associated EC bits with an associated coding function. [001431 Although features and elements are described above in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements. The methods or flow charts provided herein may be implemented in a computer program, software, or firmware incorporated in a computer readable storage medium for execution by a general purpose computer or a processor. Examples of computer-readable storage mediums include a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). [00144] Suitable processors include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in -23association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine. [00145] A processor in association with software may be used to implement a radio frequency transceiver for use in a wireless transmit receive unit (WTRU), user equipment (UE), terminal, base station, radio network controller (RNC), or any host computer, The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, a Bluetooth@ module, a frequency modulated (FM) radio unit, a liquid crystal display (LCD) display unit, an organic light-emitting diode (OLE))) display unit, a digital music player, a media player, a video game player module, an Internet browser, and/or any wireless local area network (WLAN) or Ultra Wide Band (UJWB) module. * * * -24-

Claims (23)

1. A method of feedback in a wireless transmit receive unit (WTRU), the method including: the WTRU generating a feedback signal, the feedback signal including at least one of a precoding matrix index (PMI) or a channel quality index (CQI); the WTRU determining a number of bits of the feedback signal to be encoded; the WTRU selecting a type of error detection and correction scheme to apply to the feedback signal based on the number of bits of the feedback signal to be encoded, wherein selecting the type of error detection and correction scheme includes selecting a number of error check (EC) bits to attach to the feedback signal and selecting a type of channel coding scheme to apply to the feedback signal and the selected number of EC bits; the WTRU encoding the feedback signal and the selected number of EC bits using the selected type of channel coding scheme; and the WTRU transmitting the encoded feedback signal.

2. The method as in claim 1, wherein the error detection mechanism of the error detection and correction scheme is disabled, and the number of EC bits is selected to be zero.

3. The method as in claim 1, wherein the number of EC bits includes a number of cyclic redundancy check bits.

4. The method as in claim 1, wherein the encoded feedback signal is transmitted over a data-type channel.

5. The method as in claim 4, wherein the encoded feedback signal is transmitted over the data-type channel with turbo coded user data bits.

6. The method as in claim 5, wherein the data-type channel is a physical uplink shared channel (PUSCH). 26

7. A wireless transmit receive unit (WTRU) including a processor configured, at least in part, to: generate a feedback signal, the feedback signal including at least one of a precoding matrix index (PMI) or a channel quality index (CQI); determine a number of bits of the feedback signal to be encoded; select a type of error detection and correction scheme to apply to the feedback signal based on the number of bits of the feedback signal to be encoded, wherein the processor is configured to select the type of error detection and correction scheme by selecting a number of error check (EC) bits to attach to the feedback signal and by selecting a type of channel coding scheme to apply to the feedback signal and the selected number of EC bits; encode the feedback signal and the selected number of EC bits using the selected type of channel coding scheme; and transmit the encoded feedback signal.

8. The WTRU as in claim 7, wherein the processor is configured to determine to disable the error detection mechanism of the error detection and correction scheme such that the number of EC bits to attach to the feedback signal is selected to be zero.

9. The WTRU as in claim 7, wherein the selected type of channel coding scheme includes a convolutional coding scheme.

10. The WTRU as in claim 9, wherein the selected number of EC bits includes a selected number of cyclic redundancy check (CRC) bits.

11. The WTRU as in claim 7, wherein the processor is configured to transmit a rank indicator with the encoded feedback signal.

12. The WTRU as in claim 11, wherein the processor is configured to transmit a hybrid automatic repeat request (HARQ) acknowledgement/negative acknowledgment (ACK/NACK) with the encoded feedback signal. 27

13. The WTRU as in claim 7, wherein the feedback signal includes a first group of PMIs, the processor is configured to transmit the encoded feedback signal in a first transmission time interval (TTI), a second feedback signal includes a second group of PMIs, and the processor is configured to transmit an encoded instance of the second feedback signal in a second TTI.

14. The WTRU as in clam 13, wherein the processor is configured to select a second type of error detection and correction scheme to apply to the second feedback signal based on the number of bits of the second feedback signal.

15. The WTRU as in claim 13, wherein the second error detection and correction scheme is selected to be the same error detection and correction scheme as was selected for the feedback signal.

16. A method for a wireless transmit receive unit (WTRU), the method including: the WTRU determining to transmit a first feedback signal in a first transmission time interval (TTI), wherein the first feedback signal includes a first group of precoding matrix indices (PMIs); the WTRU selecting a first type of error detection and correction scheme to apply to the first feedback signal based on a number of bits of the first feedback signal to be encoded, wherein selecting the first type of error detection and correction scheme to apply to the first feedback signal includes selecting a number of cyclic redundancy check (CRC) bits to attach to the first feedback signal and selecting a type of channel coding scheme to apply to the first feedback signal and the selected number of CRC bits; the WTRU applying the first type of error detection and correction scheme to the first feedback signal; the WTRU transmitting the encoded first feedback signal in the first TTI after applying the first type of error detection and correction scheme; the WTRU determining to transmit a second feedback signal in a second TTI, wherein the second feedback signal includes a second group of precoding matrix indices (PMIs); 28 the WTRU selecting a second type of error detection and correction scheme to apply to the second feedback signal based on a number of bits of the second feedback signal to be encoded; the WTRU applying the second type of error detection and correction scheme to the second feedback signal; and the WTRU transmitting the encoded second feedback signal in the second TTI after applying the second type of error detection and correction scheme.

17. A wireless transmit receive unit (WTRU) including a processor configured, at least in part, to: generate a feedback signal, the feedback signal including at least one of a precoding matrix index (PMI) or a channel quality index (CQI); determine a number of bits of the feedback signal to be encoded; select a number of error check (EC) bits to attach to the feedback signal based on the number of bits of the feedback signal to be encoded; selecting a type of channel coding scheme to apply to the feedback signal and the selected number of EC bits based on the number of bits of the feedback signal to be encoded; encode the feedback signal and the selected number of EC bits using the selected type of channel coding scheme; and transmit the encoded feedback signal.

18. The WTRU as in claim 24, wherein zero EC bits are selected for attachment to the first feedback signal.

19. The WTRU as in claim 24, wherein the number of EC bits include a number of cyclic redundancy check (CRC) bits.

20. The method as in claim 1, and substantially as hereinbefore described with reference to the accompanying figures. 29

21. The WTRU as in claim 7, and substantially as hereinbefore described with reference to the accompanying figures.

22. The method as in claim 16, and substantially as hereinbefore described with reference to the accompanying figures.

23. The WTRU as in claim 17, and substantially as hereinbefore described with reference to the accompanying figures. INTERDIGITAL TECHNOLOGY CORPORATION WATERMARK PATENT AND TRADE MARKS ATTORNEYS P32540AU01