HK1140332B - Feedback signaling error detection and checking in mimo wireless communication systems - Google Patents

Description

Feedback signaling error detection and checking in a MIMO wireless communication system

Technical Field

The present invention relates to wireless communications.

Background

The goal of the third generation partnership project (3GPP) Long Term Evolution (LTE) project is to develop new technologies, new architectures and new methods for provisioning and configuring in wireless communication systems to improve spectral efficiency, reduce latency and better use of radio resources for faster user experience and for lower cost, richer applications and services for lower cost users.

Wireless communication systems typically require feedback signaling for uplink and downlink communications. For example, hybrid automatic repeat request (HARQ) can actively require acknowledgement/non-acknowledgement (ACK/NACK) feedback. Adaptive Modulation and Coding (AMC) requires Channel Quality Index (CQI) feedback from the receiver. Multiple input/multiple output (MIMO) systems or precoding require rank and/or Precoding Matrix Index (PMI) feedback from the receiver. Typically, this feedback signaling is protected by coding and the signaling has no error checking or detection capability. However, efficient signaling is essential for evolved Universal Mobile Telephone System (UMTS) terrestrial radio access networks (E-UTRRANs). Adding Error Checking (EC) and error detection performance to feedback control signaling is more likely to be an even more improved application. Error Checking (EC) and error detection lead to improved signaling mechanisms, enhanced MIMO link performance, reduced system load and increased system capacity.

An example of an application that requires error detection and verification performance for feedback control signaling is precoding information verification. The precoding information verification is used to inform the WTRU about the precoding information used at the enodeb so that the effective channel including precoding effect visible to the WTRU can be reconstructed by the WTRU. This is for accurate data detection for MIMO systems using precoding, beamforming or the like.

A Wireless Transmit Receive Unit (WTRU) may feed back a Precoding Matrix Index (PMI) or antenna weights to a Base Station (BS) or an enodeb (enb). The eNB may send a verification message to the WTRU to inform the WTRU of the precoding matrix used at the eNB. Each matrix sent by the WTRU to the eNB as feedback may be indicated by PMI _ j1, PMI _ j2.. The eNB may send a verification message to the WTRU including information about the N PMIs indicated by PMI _ k1, PMI _ k2..

Each PMI may be represented by L bits. The value of L depends on a multiple input/output (MIMO) antenna configuration and a codebook size.

Communication resources may be allocated to the WTRU. A Resource Block (RB) includes M subcarriers, e.g., M12, where M is a positive integer. A Resource Block Group (RBG) or subband may include N _ RB RBs, where N _ RB equals, for example, 2, 4, 5, 6, 10, 25, or greater. The system bandwidth may have one or more RBGs or subbands that depend on the bandwidth size and the value of N _ RB for each RBG or subband.

The WTRU may feed back a PMI to each RBG or subband configured to the WTRU. The terms RBG and subband may be used interchangeably. N RBGs, where N ≦ N _ RBG, may be configured or selected by the WTRU for feedback and reporting purposes. The WTRU feeds back N PMIs to the eNB if N RBGs or subbands are configured or selected by the WTRU. The eNB sends a verification message including N PMI blocks to the WTRU.

N _ PMI is the number of bits representing the PMI. The total number of bits for WTRU PMI feedback is N xN _ PMI. The maximum number of bits for WTRU PMI feedback is N _ RBG x N _ PMI bits per feedback instance. When using the direct precoding verification mechanism, the maximum number of bits of the PMI verification message is N _ RBG x N _ PMI bits per verification message.

Table 1 shows the number of bits for WTRU PMI feedback and signaling assuming N _ PMI-5 bits. The numbers are summarized under 5, 10 and 20MHz bandwidths. The second row N _ RB is the number of RBs per RBG or subband, which is in the range of 2 to 100 for 20 MHz. Third, N _ RBG per bandwidth is the number of RBGs or subbands per 5, 10, or 20 MHz. The value of N _ RBG is in the range of 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 feedback.

TABLE 1 maximum number of bits for PMI feedback and PMI verification

As shown in the above table, PMI feedback and PMI validation requires approximately more than 250 bits per feedback instance and per validation message.

Feedback errors greatly degrade the performance of the link and system. The feedback to be protected is more desirable than a specific error check, such as channel coding. Furthermore, knowing whether there is an error in the feedback signal will improve system performance, such as link performance, because erroneous feedback information can be avoided. Furthermore, knowledge of whether there is an error in the feedback signaling enables the use of improved signaling mechanisms or applications such as precoding acknowledgement and indication mechanisms. If there is no error in the feedback signaling, a precoding confirmation is sent to confirm the correctness of the feedback signaling.

A single bit or sequence of bits may be used to precode acknowledgements and may be sufficient for some applications. The use of improved signaling, such as the use of acknowledged precoding checks, greatly reduces the signaling load. Error checking and detection is therefore desirable.

Disclosure of Invention

A method and apparatus for feedback type signaling error checking, detection and protection in a wireless communication system is disclosed. The feedback type signaling may include a Channel Quality Index (CQI), a Precoding Matrix Index (PMI), a rank, and/or an acknowledgement/non-acknowledgement (ACK/NACK). The disclosure includes a Wireless Transmit Receive Unit (WTRU) performing a method comprising: providing PMI(s), generating Error Check (EC) bit(s), encoding the PMI(s) and the EC bit(s), and transmitting the encoded PMI(s) and EC bit(s). The method is applied to other feedback information such as CQI, rank, ACK/NACK and the like.

Drawings

The invention will be understood in more detail from the following description of preferred embodiments, given by way of example and understood in conjunction with the accompanying drawings, in which:

figure 1 shows a wireless communication system including a plurality of WTRUs and an eNB;

figure 2 is a functional block diagram of a WTRU and an eNB in the wireless communication system of figure 1;

fig. 3 is a block diagram of PMI feedback with error checking and correction according to one embodiment;

fig. 4 is a block diagram of PMI feedback with error checking and correction according to another embodiment;

fig. 5 is a block diagram of PMI feedback with error checking and correction according to an alternative embodiment;

fig. 6 is a block diagram of PMI feedback with error checking and correction according to another alternative embodiment;

fig. 7 is a block diagram of PMI feedback with error checking and correction according to yet another alternative embodiment;

fig. 8 is a block diagram of PMI feedback with error checking and correction according to yet another alternative embodiment;

fig. 9 is a block diagram of PMI feedback with error checking and correction according to yet another alternative embodiment;

fig. 10 is a block diagram of PMI feedback with error checking and correction according to yet another alternative embodiment;

FIG. 11 is a block diagram of PMI, CQI and ACK/NACK feedback with error check and correction, according to yet another alternative embodiment; and

fig. 12 is a block diagram of PM, CQI and ACK/NACK feedback with error checksum correction according to yet another alternative embodiment.

Detailed Description

The term "wireless transmit/receive unit (WTRU)" as referred to below includes, but is not limited to, a User Equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, a wireless telephone, a Personal Digital Assistant (PDA), a computer, or any other type of user device capable of operating in a wireless environment. The term "base station" as referred to below includes, but is not limited to, a node B, a site controller, an Access Point (AP), or any type of interfacing device capable of operating in a wireless environment.

Fig. 1 shows a wireless communication system 100, the wireless communication system 100 including a plurality of WTRUs 110 and an eNB 120. Although three WTRUs 110 and one eNB120 are shown in fig. 1, it should be noted that any combination of wireless and wired devices may be included in the wireless communication system 100.

Fig. 2 is a functional block diagram 200 of the WTRU 110 and the eNB120 in the wireless communication system 100 shown in fig. 1. As shown in fig. 2, the WTRU 110 communicates with the eNB 120. The WTRU 110 is configured to send feedback signals and control signals to the eNB 120. The WTRU is also configured to receive feedback and control signals from the eNB and to send the feedback and control signals to the eNB. Both the eNB and the WTRU are configured to process the modulated and encoded signals.

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 the receiver 216 and the transmitter 217 to facilitate the transmission and reception of wireless data.

In addition to the components found in a typical eNB, the eNB120 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 the receiver 226 and the transmitter 227 to facilitate the transmission and reception of wireless data.

The WTRU may send a feedback signal (e.g., PMI feedback) to the eNB. Error Check (EC) (e.g., Cyclic Redundancy Check (CRC)) bits may be appended to the feedback signal (e.g., PMI feedback). Both the feedback signal (e.g., PMI) and the EC bits are encoded prior to transmission. The feedback signal may comprise a PMI, CQI, rank, ACK/NACK, or other type of feedback signal. While the present disclosure refers to PMI bits, CQI bits, EC bits, and the like, one skilled in the art will recognize that PMI feedback, CQI feedback, error checking and correction may be, and in most cases is, multi-bit. Although feedback signals such as PMI or CQI are used as examples, other feedback signals may also be used.

Different types of channels may be used to transmit and carry feedback type signals. For example, both control type channels and data type channels may be used to carry feedback type signals. An example of a control type channel is a Physical Uplink Control Channel (PUCCH). An example of a data type channel is a Physical Uplink Shared Channel (PUSCH). Those skilled in the art will recognize that the methods and apparatus disclosed herein are independent of channel selection.

The PMI and EC bits may be encoded with or without data bits. Both the data type channel and the control type channel may be used to send the feedback signal and the EC bit. For example, a data type channel, such as a Physical Uplink Shared Channel (PUSCH), may be used to transmit the PMI and EC bits. A control type channel, such as a Physical Uplink Control Channel (PUCCH), may be used to transmit the PMI and EC bits.

Alternatively, the PMI and EC bits may be encoded with a first encoding scheme, and the data bits may be encoded with a second encoding scheme. Each coding scheme may be different. For example, convolutional coding or Reed-Muller (Reed-Muller) coding may be used for feedback type signals, while turbo coding is used for data type signals. Alternatively, the encoding scheme may be the same, but with different parameters and settings to address the different error rate requirements of the feedback type signal and the data type signal. A data type channel (e.g., PUSCH) may be used to transmit the PMI and EC bits. A control type channel (e.g., PUCCH) may also be used to transmit PMI and EC bits.

If the packet is used for feedback type signaling, the PMI and EC bits may be encoded separately for each group.

All PMI and/or EC bits may be fed back or reported at the same time. For example, all PMI and/or EC bits may be reported at the same Transmission Time Interval (TTI). Alternatively, the feedback type bits and the error check bits may be reported at different times. For example, PMI and/or EC bits may be partitioned into groups and reported at different TTIs.

Error checking and detection methods such as Cyclic Redundancy Check (CRC) may be used. If a CRC is used, the CRC may be, for example, a 24-bit CRC or a 16-bit CRC. The length of the CRC is variable and the actual length used may depend on design choice.

The CRC bits may be appended to the feedback type signal and transmitted over the data type channel to carry the feedback type signal bits and the CRC bits. The feedback type signal may be, for example, PMI, CQI, rank, or ACK/NACK. The data type channel may be, for example, PUSCH. The data type channel has a large capacity and can accommodate a relatively large number of bits. Thus, the CRC may be, for example, a 24-bit CRC, a 16-bit CRC, or some other length of CRC. A long CRC may be used and is preferred because it provides a better error check. However, this would increase extra overhead due to the addition of CRC bits, but PUSCH has the capacity to handle a large number of bits. The use of a data channel, e.g., PUSCH, allows transmission of feedback signals such as PMI, CQI, rank, and ACK/NACK in a single TTI. Thus, a feedback type signal with a long CRC providing better error checking performance can be realized.

Alternatively, the CRC bits may be appended to the feedback type signal and transmitted on the control type channel. The CRC may be a 24 bit CRC, a 16 bit CRC, or other length CRC. Typically, a control type channel may not have a large capacity to carry a large number of bits. The transmission may be divided and transmitted at multiple times to transmit the CRC bits and the feedback type signal. The PMI feedback signal may be divided and transmitted over multiple TTIs. For example, one PMI may be transmitted on each TTI until all feedback signals are transmitted. The CQI or other feedback signal may be processed in the same manner.

PMI, CQI, and/or other feedback type signals may be transmitted at different times or different TTIs, respectively. In general, a control type channel (e.g., PUCCH) cannot carry a large number of bits at a time, and if there are a large number of feedback bits to send, the feedback bits may be divided or partitioned into groups. Each group may report one at a time. Each feedback instance may include a single PMI, CQI, other feedback signal, or a combination of feedback signals. The CRC may be fed back or transmitted at the same time (in the same TTI) like PMI or CQI. Alternatively, the CRC may be fed back or transmitted from the PMI or CQI, respectively. That is, C may transmit the CRC at a different time or in a different TTI than the time or TTI at which the PMI or CQI is transmitted. The CRC may also be divided into segments or groups, and each CRC segment may be transmitted or fed back at the same time or in the same TTI as the feedback signal. Each CRC segment may also be transmitted at a different time or a different TTI.

The use of CRC appended to the feedback signal may be applied to a single feedback signal, such as a PMI and/or a CQI. This single feedback mechanism may be used when non-frequency selective feedback or wideband feedback (one feedback per entire bandwidth or per entire configured bandwidth).

Other error checking or detection methods such as parity (including single bit parity) or block parity may also be used. As can be appreciated by those skilled in the art, the disclosure herein is not limited to any particular error checking mechanism.

Encoding mechanisms such as convolutional encoding, Reed-Solomon (Reed-Solomon) or Reed-Muller encoding may be used. Other coding schemes, such as turbo coding and Low Density Parity Check (LDPC) coding, are also contemplated. If the feedback is sent over a data type channel, such as the physical link shared channel (PUSCH), convolutional or block coding is appropriate, since the data type channel, such as the PUSCH, allows for the transmission of a large number of bits. Reed-Muller or Reed-Solomon encoding is also suitable, as a suitable number of bits are encoded by these encoding schemes. As can be appreciated by those skilled in the art, the disclosure herein is not limited to any one particular encoding mechanism.

Fig. 3 is a block diagram 300 of PMI feedback with error checking and correction, according to one embodiment. A plurality of PMIs configured as PMI _ 1302, PMI _ 2304, PMI _ 3306 to PMI _ N-1308, and PMI _ N310 are shown in fig. 3. EC bit 312 is appended to PMI signal 316. The EC bits 312 may be CRC bits of 24 bits, 20 bits length, or 16 bits length. Other lengths of CRC may also be used. The PMI bits (302-310) and EC bits 312 are encoded by a channel coding function 314 prior to transmission. All PMIs and ECs may be co-coded (joint) for channel coding. The jointly encoded PMI and EC may be transmitted at the same time or on the same TTI. The jointly encoded PMI and EC may be transmitted at different times or TTIs. Alternatively, channel coding may be performed separately for each PMI and EC bit or for a group of PMI and EC. The EC bits may be divided into segments, and each EC bit segment may be channel coded and transmitted, respectively.

For example, if there are an integer "N" PMIs, each PMI may be 4 bits and each EC may be 24 bits, e.g., using a 24-bit CRC. The total number of bits is 4N +24 bits. The total number of bits may be jointly encoded using channel coding (e.g., convolutional coding). The coded bits may be transmitted or fed back at once over a single TTI. The total number of coded bits may also be transmitted or fed back at different times or different TTIs. For example, the encoded bits are sent an integer number "M" of times over M different TTIs. (4N +24)/M original information and CRC bits may be transmitted per TTI. The (4N +24)/M original information and CRC bits may include PMI bits and/or CRC bits in each TTI. If the TTI includes a combination of PMI and CRC bits, 4N/M PMI bits and 24/M CRC bits may be included in a single TTI. If M is N, 4 PMI bits and partial CRC bits may be transmitted in a single TTI.

Alternatively, the 24-bit CRC may be divided into 6 segments of 4 bits each, with the same number of bits in the PMI. Each PMI and each CRC segment may be encoded and transmitted separately or together over a TTI.

For example, the EC bit 312 may be a CRC. The channel coding function 314 may be, for example, convolutional coding. Error checking and detection methods such as parity checking and other channel coding methods such as Reed-Muller coding or Reed-Solomon coding may also be used.

Each PMI may represent precoding information for a subband, an RBG, a group of subbands, or a wideband. For example, PMI _1 may be a wideband PMI (the "average" precoding information over the entire band), and PMI _2 to PMI _ N may be subband PMIs or average PMIs, each corresponding to precoding information of a subband and an RBG or a group of subbands.

Likewise, CQI and other feedback type signals may error check performance by appending the previously described CRC increase after channel coding and transmission.

PMI feedback signaling may be combined into groups with separate error checking for each group. EC bits may be appended to each set of PMIs prior to channel coding.

Fig. 4 is a block diagram 400 of PMI feedback with error checking and correction according to another embodiment, where PMI _1402, PMI _2404 and PMI _ 3406 are grouped together with an appended first error check EC (1) 408. PMI _ 4410, PMI _5412 and PMI _ 6414 are grouped together and EC (2)416 is appended. PMI _ N-2418, PMI _ N-1420 and PMI _ N422 are grouped together with the addition of EC (G) 424. The PMIs (402-.

As described above, EC may be CRC. The error checking, detecting and correcting method may be selected based on the total number of bits encoded. EC may use, for example, shorter or long CRCs, single parity bits, or block parity bits. Other error checking, correction and detection methods, such as modified parity, may also be used.

A channel coding function such as convolutional coding or Reed-Solomon coding may be used. Other channel coding methods, such as block coding, turbo coding, or LDPC, may also be used.

The PMIs may be divided into several groups and these PMI groups may be transmitted over different Transmission Time Intervals (TTIs). These PMI groups may also be transmitted over a single TTI. Each group may be reported after channel coding. This refers to frequency selective feedback and reporting of multiple PMIs. The CQI, rank, and ACK/NACK signals may also be fed back or reported on a frequency selective basis.

PMI _1402, PMI _2404, PMI _ 3406, and EC (1)408 may be reported over a single TTI, e.g., TTI (1). PMI _ 4410, PMI _5412, PMI _ 6414, and EC (2)416 may be reported on a second TTI, e.g., TTI (2). PMI _ N-2418, PMI _ N-1420, PMI _ N422, and EC (G)424 may be reported in another TTI, e.g., TTI (G).

If an error detection or checking mechanism is not available or if the error detection or checking capability is removed, no EC bit will be attached. In this case, PMI group 1(PMI _1402, PMI _2404, PMI _ 3406) may be reported on TTI (1), PMI group 2(PMI _ 4410, PMI _5412, PMI _ 6414) may be reported on TTI (2), and PMI group G (PMI _ N-2418, PMI _ N-1420, PMI _ N422) may be reported on TTI (G). Reporting may occur with or without an EC bit.

Fig. 5 is a block diagram of PMI feedback with error checking and correction according to an alternative embodiment. Error check bit EC (1)508 is used for PMI _ 1502, PMI _ 2504, and PMI _ 3506. Error check bits EC (2)516 are used for PMI _ 4510, PMI _ 5512 and PMI _ 6514, and error check bits EC (G)528 are used for PMI _ N-2522, PMI _ N-1524 and PMI _ N526. The PMI bits and EC bits are encoded by a channel encoding function 540 before transmission.

In another alternative embodiment, the PMIs may be divided into groups, with each group having an associated error detection and check value. The feedback signaling and the error checking of each group are encoded separately. The encoded feedback bits and EC bits may be transmitted over the same TTI or different TTIs. Each PMI packet is encoded separately from its associated EC.

Fig. 6 is a block diagram 600 of PMI feedback with error checking and correction according to another alternative embodiment. The PMIs are divided into G groups for error detection and/or correction. EC (1)620 is appended to PMI _ 1602, PMI _ 2604 and PMI _ 3606, EC (2)622 is appended to PMI _4608, PMI _ 5610 and PMI _ 6612, and EC (N)624 is appended to PMI _ N-2614, PMI _ N-1616 and PMI _ N618. PMI _ 1602, PMI _ 2604, PMI _ 3606, and EC (1)620 are encoded by the first channel encoding function 630. PMI _ 4612, PMI _ 5614, and PMI _6616 are encoded by the second channel encoding function 640 together with EC (2) 622. PMI _ N-2614, PMI _ N-1616 and PMI _ N618 are encoded by the G-th channel coding function 650 together with EC (G) 824. The error checking, correcting and detecting method may be selected based on the number of bits that are required to be encoded. EC may use a CRC of, for example, 24 bits, 20 bits, or 16 bits. The EC may also use a single parity bit or block parity bit of less than 16 bits. For example, the EC may also use error checking and detection methods such as modified parity.

Channel coding functions 630, 640, and 650 may use, for example, convolutional coding or Reed-Solomon coding. Other suitable channel coding such as block coding, turbo coding, or LDPC may also be used.

The EC bits may be divided into groups, and each group of bits may be fed back or reported at the same time or at different times. For example, each set of EC bits may be fed back or reported in the same or different TTIs. Each group is reported after channel coding, either jointly or separately, for each group.

Each PMI group may be reported on a different TTI or together in the same TTI. Each group is reported after being separately channel coded. Other feedback signals such as CQI, rank, and ACK/NACK may also be used.

PMI _ 1602, PMI _ 2604, PMI _ 3606, and EC (1)620 may be reported on TTI (1). PMI _4, PMI _5, PMI _6, and EC (2) may be reported on TTI (2), and PMI _ N-2, PMI _ N-1, PMI _ N, and EC (G) may be reported on TTI (G).

If an error detection or checking mechanism is not available, or if error detection or checking performance is removed, then no EC bit is attached. PMI groups may be reported without EC bits. PMI group 1(PMI _1402, PMI _2404, PMI _ 3406) may be reported in TTI (1), PMI group 2(PMI _ 4410, PMI _5412, PMI _ 6414) may be reported in TTI (2), and PMI group G (PMI _ N-2418, PMI _ N-1420, PMI _ N422) may be reported in TTI (G). Each report group has a separate channel code.

When the number of PMI groups is equal to the number of PMIs (G ═ N), then there is one PMI per PMI group. Each PMI may be separately attached to EC (e.g., CRC) bits and encoded. Each PMI may be reported at a different time. PMI _ 1702, PMI _ 2704, and PMI _ N706 may be reported in different TTIs. For example, PMI _ 1702 may be reported on TTI (1), PMI _ 2704 on TTI (2), and PMI _ N706 on TTI (N). Feedback or reporting may be performed over a control type channel, such as a Physical Uplink Control Channel (PUCCH).

Alternatively, the PMI _ 1704, PMI _ 270, PMI _ N706 may be reported at the same time. For example, the PMI _ 1704 to PMI _ N706 may be reported in a single TTI. This may occur through a data type channel (e.g., PUSCH) where more bits are processed depending on the capabilities of the data type channel (e.g., PUSCH). Other feedback signals such as CQI, rank, and ACK/NACK may be used with or in place of PMI.

Fig. 7 is a block diagram of PMI feedback for error checking and correction according to yet another alternative embodiment. The PMI is divided into G groups for error checksum detection, G ═ N. PMI _ 1702 is appended with error check bits EC (1)712, PMI _ 2704 is appended with EC (2)714, and PMI _ N706 is appended with EC (2) 716. Each PMI/EC pair is encoded by a channel encoding function 720. Suitable error checking, correction and error detection mechanisms may be used and may depend on the number of bits that need to be encoded. For example, a particular EC may use a CRC, such as a 24-bit CRC, a short CRC, a single check bit, or a block check bit. For example, the channel coding may use Reed-Solomon coding. Other suitable error checksum detection may be used, such as a long CRC or other parity check mechanism. Other suitable channel coding may also be used, such as block coding, convolutional coding, turbo coding, or LDPC.

Using frequency selective reporting, PMI _ 1702 may be reported in TTI (1), PMI _ 2704 may be reported in TTI (2), and PMI _ N706 may be reported in TTI (N). These PMIs may be reported over a control type channel (e.g., PUCCH). Alternatively, PMI _1 to PMI _ N may be reported on a single TTI through a data type channel (e.g., PUSCH). Other feedback signaling such as CQI, rank, and ACK/NACK may be used.

Fig. 8 is a block diagram of PMI feedback with error checking and correction according to yet another alternative embodiment. EC (1)812 may be used for PMI _ 1802, EC (2)814 may be used for PMI _2(804), and EC (N)816 may be used for PMI _ N (806). The PMI and EC may be separately encoded or jointly encoded at channel encoding function 820.

PMI _ 1802 may be reported in TTI (1), and PMI _ 2804 may be reported in TTI (2). And PMI (N)806 may be reported in TTI (N). PMI _ 1802, PMI _ 2804, and PMI _ N806 may be encoded and reported separately on different or the same TTI. Alternatively, PMI _ 1802, PMI _ 2804, and PMI _ N806 may be jointly encoded and reported on the same TTI. Alternatively, PMI _ 1802, PMI _ 2804, and PMI _ N806 may be encoded separately using different protection mechanisms and reported on the same TTI. CQI, rank, and ACK/NACK may also be used.

Fig. 3-8 depict error checking, encoding, and feedback for PMI, and show a single type of feedback signal. CQI and other types of feedback signals may replace PMI.

Fig. 9-12 depict error checking, encoding, transmission, and feedback for more than one type of feedback signal. Fig. 9 to 12 are described in detail below.

PMI feedback and other types of control signaling may be error checked with the same or different error checks, respectively, and encoded together. For example, a first type feedback signal, which may be a PMI, may be appended to a first EC, which may be a CRC, such as a 24-bit CRC. The same EC may be attached to the second type of feedback signal, which may be a CQI.

In another embodiment, a first type feedback signal, which may be a PMI, may be appended to an EC, which may be a CRC, e.g., a 24-bit CRC. The second type of feedback signal may append a second EC, which may be a 16-bit CEC.

In general, different error checking and/or correction may be used for different types of feedback signals or different feedback signals of the same type. The choice of which error checking and/or correction to use may involve design decisions of robustness versus overhead. A longer CRC may give more protection, but more bits are also built up. Thus, if one type of feedback signal is more important than another type of feedback signal, longer error checking and/or correction capabilities may be provided for the more important type of feedback signal. Similar to the same type of feedback signal, if one feedback signal or group of feedback signals is more important than another feedback signal or group of feedback signals, stronger error checking and/or correction capabilities may be provided for the more important feedback signal or group of feedback signals.

Referring again to the example provided above, if the first feedback signal, which may be a PMI, is more important than the second feedback signal, which may be a CQI, a longer CRC with error checking and detection capability may be used for the PMI and a shorter CRC with error checking and detection capability may be used for the CQI.

Applying different error checking and/or correction capabilities to the feedback signals may protect important feedback signals, optimize link performance, and minimize signaling overhead.

Fig. 9 is a block diagram 900 of PMI feedback with error checksum correction and Channel Quality Index (CQI) feedback with error checksum correction, according to yet another embodiment. A first EC 930 (e.g., CRC) is attached to PMI _ 1902, PMI _ 2904, PMI _ 3906 through PMI _ N908. A second EC 940, such as a CRC, is appended to CQI-1912 through CQI-M914. The EC of the additional PMI signal 910 and the CQI signal 920 are encoded together in a channel coding function 950 to generate a single transmitted signal.

In fig. 9, the first EC 930 and the second EC 940 may be the same. This will provide equal error checksum protection for each feedback signal.

Alternatively, the first EC 930 and the second EC 940 may be different. The first EC 930 may be more efficient if PMI feedback is more important to system performance than CQI feedback. For example, the first EC may be a 24-bit CRC and the second EC may be a 16-bit CRC.

The PMI feedback signal may include a "wideband" PMI, a "narrowband" PMI, a "subband" PMI, and/or an average PMI. Similarly, the CQI feedback signal may include a "wideband" PMI, a "narrowband" PMI, a "subband" PMI, and/or an average PMI.

As shown in fig. 3-8, the EC bits and feedback bits may be transmitted in a single TTI, or may be divided into multiple TTIs, similar to embodiments including a single feedback. More particularly, a data type channel (such as PUSCH) may be used to send feedback bits and EC bits over a single TTI, because the data type channel is able to handle a greater number of bits per TTI.

The coding for the feedback bits and the EC bits may also be the same with the same or different weights, or may be different. Those skilled in the art will recognize that there are many possible combinations of encoding, transmission and error checking.

Fig. 10 is a block diagram 100 of PMI and CQI feedback according to yet another embodiment. The feedback signal may be appended with error checking bits and encoded together. The signals including PMI _ 11002 to PMI _ N1004 are input to the EC add/insert function 1020 together with the signals including CQI _ 11012 to CQI _ M1014. The signal is processed by an EC function 1020 and the single output signal is input to a channel coding function 1030 prior to transmission.

Control signaling other than CQI including rank and ACK/NACK may also be used.

Fig. 11 is a block diagram 1100 of PMI feedback with error check sum correction, CQI feedback with error check sum correction, and ACK/NACK feedback according to yet another embodiment. The first EC 1110 is appended to the PMI _ 11102 to the PMI _ N1104. The second EC 1120 is attached to CQI _ 11112 through CQI _ M1114. The PMI signal 1106, the CQI signal 1116, and the ACK/NACK signal 1130 are input to a channel coding function 1140.

The ACK/NACK feedback signal 1130 may replace the rank feedback signal in fig. 12. Alternatively, a rank feedback signal may be added to fig. 12.

Fig. 12 is a block diagram 1200 of PMI feedback and CQI feedback with ACK/NACK feedback according to yet another embodiment. The CQI, PMI and ACK/NACK may be encoded together but error checked separately. The PMI signal 1202 including the PMI _ 11204 to the PMI _ N1206, the CQI signal 1212 including the CQI _11214 to the CQI _ M1216, and the ACK/NACK signal 1220 are input to the EC addition/insertion function 1230. The single signal output is processed through a channel coding function 1240 and transmitted. An EC (e.g., CRC) is appended to the combined signal prior to encoding and transmission.

The ACK/NACK feedback signal 1220 may be replaced with a rank feedback signal in fig. 12. Alternatively, the feedback signal may be added to fig. 12.

The PMI, CQI, and ACK/NACK signals may have different error checking and/or protection. For example, the PMI may have the highest error checking and/or error protection, while the CQI has a lower error checking and/or error protection. When different error checking and/or coding mechanisms are used or the same error checking and/or coding mechanism is used, the PMI, CQI, and ACK/NACK may have different error checking and/or protection. Different weights may be used on the PMI, CQI, and ACK/NACK signals. Different error checking and/or error protection may be obtained by using different error checking and/or coding schemes, or by using the same error checking and/or coding scheme, but by using the same error checking and/or coding and protection scheme may have different important weights on different feedback types of signals. This may be applicable to other feedback signaling such as rank.

Similarly, the PMI feedback signal may include a "wideband" PMI, a "narrowband" PMI, a "subband" PMI, and/or an average PMI. Similarly, the CQI feedback signal may include a "wideband" CQI, a "narrowband" CQI, a "subband" CQI, and/or an average CQI.

Examples

1. A method of feedback in a Wireless Transmit Receive Unit (WTRU), the method comprising: providing a Precoding Matrix Index (PMI); error checking the PMI to generate Error Check (EC) bits; encoding the PMI and EC bits; and transmitting the encoded PMI and EC bits.

2. The method of embodiment 1 further comprising grouping a plurality of PMIs into PMI groups.

3. The method of embodiment 1 or 2, further comprising error checking each PMI group of a plurality of PMIs to generate the EC bit.

4. The method of embodiment 2 or 3, further comprising: performing error checking on each of a plurality of PMI groups to generate a plurality of EC-bits, wherein one EC-bit of the plurality of EC-bits is appended to each PMI group; and encoding the appended EC bits together with the corresponding PMI group.

5. The method of any of embodiments 2-4, further comprising: performing error checking on each of a plurality of PMI groups to generate a plurality of EC-bits, wherein one EC-bit of the plurality of EC-bits is appended to each PMI group; and encoding the EC bits after encoding the PMI group.

6. The method of 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 of PMI groups; and encoding each of the plurality of PMI groups and associated EC bits with an associated encoding function.

7. The method as in any one of embodiments 3-6 wherein the number of PMI groups is equal to the number of EC bits.

8. The method of any of embodiments 3-7, further comprising: error checking is performed on each PMI group separately; and encoding the plurality of PMI groups and the EC bits together.

9. The method of any of embodiments 3-8, further comprising: error checking is performed on each PMI group separately; and encoding the plurality of PMI groups and the EC bits, respectively.

10. The method of any of embodiments 1-9, further comprising: providing a control index; error checking the control index to generate a second EC bit; and encoding the PMI and the EC bit together with the control index and the second EC bit.

11. The method of embodiment 10, further comprising: providing an error detection signal; and encoding the PMI, the control index, the EC bit, the second EC bit, and the error detection signal.

12. The method of embodiment 11 wherein the error detection signal is an acknowledgement/non-acknowledgement (ACK/NACK) signal.

13. A method of feedback in a Wireless Transmit Receive Unit (WTRU), the method comprising: providing a Precoding Matrix Index (PMI); providing a control index; error checking the PMI and a control index to generate Error Check (EC) bits; encoding the PMI, a control index and EC bits.

14. The method of embodiment 13 further comprising transmitting the encoded PMI, control index and EC bit to a base station.

15. The method of embodiment 13 or 14, wherein the control index is a Channel Quality Index (CQI).

16. A wireless transmit/receive unit (WTRU) comprising: a processor configured to: determining a Precoding Matrix Index (PMI); error checking the PMI to generate Error Check (EC) bits; and encoding the PMI and EC bits; and a transmitter configured to transmit the encoded PMI and EC bits.

17. The WTRU of embodiment 16 wherein the processor is further configured to group the plurality of PMIs into PMI groups.

18. The WTRU of embodiment 17 wherein the processor is further configured to error check each of the plurality of PMI groups to generate the EC bit.

19. The WTRU of embodiment 17 or 18, wherein the processor is further configured to: error checking each of a plurality of PMI groups to generate a plurality of EC-bits, wherein one EC-bit of the plurality of EC-bits is appended to each PMI group; and encoding the appended EC bits together with the corresponding PMI group.

20. The WTRU as in any one of embodiments 17-19, wherein the processor is further configured to: error checking each of the plurality of PMI groups to generate a plurality of EC-bits, wherein one EC-bit of the plurality of EC-bits is appended to each PMI group; and encoding the EC bits after encoding the PMI group.

21. The WTRU of embodiment 20 or 21, wherein the processor is further configured to: determining a plurality of coding functions, wherein each of the plurality of coding functions is associated with one of the plurality of PMI groups; encoding each of the plurality of PMI groups and associated EC bits with an associated encoding function.

22. The WTRU as in any one of embodiments 19-21 wherein the number of PMI groups is equal to the number of EC bits.

23. The WTRU as in any one of embodiments 19-22 wherein the processor is further configured to: error checking is performed on each PMI group separately; and encoding the plurality of PMI groups and the EC bits together.

24. The WTRU as in any one of embodiments 19-23, wherein the processor is further configured to: error checking is performed on each PMI group separately; and encoding the plurality of PMI groups and the EC bits, respectively.

25. The WTRU as in any one of embodiments 16-23, wherein the processor is further configured to: determining a control index; error checking the control index to generate a second EC bit; and encoding the PMI and EC bits together with the control index and second EC bit.

26. The WTRU of embodiment 25, wherein the processor is further configured to: determining an error detection signal; and encoding the PMI, the control index, the EC bit, the second EC bit, and the error detection signal.

27. The WTRU as in embodiment 25 or 26 wherein the error detection signal is an acknowledgement/non-acknowledgement (ACK/NACK) signal.

28. A method of feedback in a Wireless Transmit Receive Unit (WTRU), the method comprising: providing a feedback bit; error checking the feedback bits to generate Error Check (EC) bits; encoding the feedback bits and EC bits; and transmitting the encoded feedback bits and EC bits.

29. The method of embodiment 28 further comprising grouping a plurality of the feedback bits into feedback groups.

30. The method of embodiment 28 or 29, further comprising error checking each of a plurality of feedback groups to generate the EC bit.

31. The method as in any one of embodiments 28-30 wherein the feedback bits comprise a Precoding Matrix Index (PMI).

32. The method as in any one of embodiments 28-31 wherein the feedback bits comprise a Channel Quality Index (CQI).

33. The method as in any one of embodiments 28-32 wherein the feedback bits comprise a rank.

34. The method as in any one of embodiments 28-33 wherein the feedback bits comprise acknowledgement/non-acknowledgement (ACK/NACK).

35. The method as in any one of embodiments 28-34 wherein the EC bit comprises a Cyclic Redundancy Check (CRC).

36. The method as in any one of embodiments 28-35 further comprising encoding the EC bit and the feedback bit together.

37. The method as in any one of embodiments 28-36 further comprising encoding the EC bit and the EC bit separately.

38. The method as in any one of embodiments 28-37 further comprising transmitting the feedback bits and EC bits in a single Transmission Time Interval (TTI).

39. The method as in any one of embodiments 28-38 further comprising transmitting the feedback bits and the EC bits on separate TTIs.

40. The method as in any one of embodiments 28-39 further comprising transmitting the feedback bits and a portion of the EC bits over a single TTI.

41. The method of any one of embodiments 29-40, further comprising error checking each of a plurality of feedback groups to generate a plurality of EC-bits, wherein one EC-bit of the plurality of EC-bits is appended to each feedback group; and encoding the EC bit after encoding the feedback group.

42. The method of embodiment 41, further comprising providing a plurality of encoding functions, wherein each of the plurality of encoding functions is associated with one of the plurality of feedback groups; and encoding each of the plurality of feedback groups and the associated EC bit with an associated encoding function.

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. The methods or flow charts provided in the present invention may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium for execution by a general purpose computer or a processor. Examples of the computer readable storage medium include Read Only Memory (ROM), Random Access Memory (RAM), registers, 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 optical disks and Digital Versatile Disks (DVDs).

For example, suitable processors include: 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 conjunction with a DSP core, a controller, a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) circuit, any Integrated Circuit (IC), and/or a state machine.

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 video phone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, and BluetoothA module, a Frequency Modulation (FM) radio unit, a Liquid Crystal Display (LCD) display unit, an Organic Light Emitting Diode (OLED) 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) module or Ultra Wideband (UWB) module.

Claims (16)

1. A method of feedback in a Wireless Transmit Receive Unit (WTRU), the method comprising:

determining feedback, wherein the feedback comprises a Precoding Matrix Index (PMI);

appending Error Check (EC) bits to the feedback;

encoding the feedback and the EC bits using a channel coding function; and

and sending the feedback and EC bits after channel coding.

2. The method of claim 1, wherein the feedback further comprises a plurality of PMIs, and further comprising:

grouping the plurality of PMIs into a plurality of PMI groups;

appending a corresponding EC bit to each of the plurality of PMI groups; and

channel coding at least one of the corresponding EC-bits together with the corresponding PMI group.

3. The method of claim 2, further comprising:

providing a plurality of channel coding functions, wherein each of the plurality of channel coding functions is associated with one of the plurality of PMI groups; and

encoding each of the plurality of PMI groups and associated EC bits with an associated channel coding function.

4. The method of claim 3, further comprising:

error checking is separately performed on each PMI group, and channel coding is performed on the plurality of PMI groups together with the plurality of EC bits.

5. The method of claim 3, further comprising:

error checking is separately performed for each PMI group, and channel coding is performed for the plurality of PMI groups and the plurality of EC bits, respectively.

6. The method of claim 1, further comprising:

providing a control index and error checking the control index to generate a second EC bit; and

encoding the feedback and the EC-bit together with the control index and the second EC-bit using the channel coding function.

7. The method of claim 6, further comprising:

determining an error detection signal; and

channel coding the feedback, the control index, the EC-bit, the second EC-bit, and the error detection signal.

8. The method of claim 7, wherein the error detection signal is an acknowledgement/non-acknowledgement (ACK/NACK) signal.

9. A wireless transmit/receive unit (WTRU), comprising:

a processor configured to:

determining feedback, wherein the feedback comprises a Precoding Matrix Index (PMI),

adding an Error Check (EC) bit to the feedback, and

encoding the feedback and the EC bits using a channel coding function; and

a transmitter configured to transmit the channel coded feedback and the EC bits.

10. The WTRU of claim 9, wherein the feedback further comprises a plurality of PMIs, and the processor is further configured to:

grouping the plurality of PMIs into a plurality of PMI groups;

appending a corresponding EC bit to each of the plurality of PMI groups; and

encoding each of the corresponding EC-bits together with the corresponding PMI group using a corresponding channel coding function.

11. The WTRU of claim 10, wherein the processor is further configured to:

determining a plurality of channel coding functions, wherein each of the plurality of channel coding functions is associated with one of the plurality of PMI groups; and

encoding each of the plurality of PMI groups and associated EC bits with an associated channel coding function.

12. The WTRU as in claim 11 wherein the processor is further configured to error check each PMI group separately and channel code the plurality of PMI groups and the plurality of EC bits together.

13. The WTRU as in claim 11 wherein the processor is further configured to error check each PMI group separately and channel code the plurality of PMI groups and the EC bits separately.

14. The WTRU of claim 9, wherein the processor is further configured to:

determining a control index and performing error checking on the control index to generate a second EC bit; and

channel coding the feedback and the EC-bit together with the control index and the second EC-bit.

15. The WTRU of claim 14, wherein the processor is further configured to:

determining an error detection signal; and

channel coding the feedback, the control index, the EC-bit, the second EC-bit, and the error detection signal.

16. The WTRU of claim 15 wherein the error detection signal is an acknowledgement/non-acknowledgement (ACK/NACK) signal.