阅读说明：本技术 无线通信系统中的码块组(cbg)级重传 (Code Block Group (CBG) level retransmission in a wireless communication system ) 是由 蔡承融 于 2020-01-08 设计创作，主要内容包括：一种数据重传方法,该方法可以包括以下步骤：在无线通信系统中的接收器处从发送器接收与第一混合自动重传请求(HARQ)进程相对应的、包括码块组(CBG)的传输块(TB),并且从所述接收器发送TB/CBG指示符以及HARQ重传信息。所述HARQ重传信息包括针对所述第一HARQ进程的HARQ确认(HARQ-ACK)反馈或重传指示。所述TB/CBG指示符指示所述HARQ-ACK反馈或重传指示是TB级还是CBG级。(A method of data retransmission, the method may comprise the steps of: a Transport Block (TB) including a code group (CBG) corresponding to a first hybrid automatic repeat request (HARQ) process is received from a transmitter at a receiver in a wireless communication system, and a TB/CBG indicator and HARQ retransmission information are transmitted from the receiver. The HARQ retransmission information comprises HARQ acknowledgement (HARQ-ACK) feedback or retransmission indication for the first HARQ process. The TB/CBG indicator indicates whether the HARQ-ACK feedback or retransmission indication is of a TB level or a CBG level.)

1. A method, comprising:

receiving, at a receiver in a wireless communication system, a Transport Block (TB) including one or more Code Block Groups (CBGs) corresponding to a first hybrid automatic repeat request (HARQ) process from a transmitter; and

transmitting, from the receiver, a TB/CBG indicator and HARQ retransmission information, the HARQ retransmission information including HARQ acknowledgement (HARQ-ACK) feedback or a retransmission indication for the first HARQ process, the TB/CBG indicator indicating whether the HARQ-ACK feedback or the retransmission indication is of a TB level or a CBG level.

2. The method of claim 1, wherein the transmitter is a Base Station (BS) and the receiver is a User Equipment (UE) in the wireless communication system, and

the HARQ retransmission information is a HARQ-ACK codebook that includes HARQ-ACK feedback for a plurality of HARQ processes configured at the UE.

3. The method of claim 2, wherein the TB/CBG indicator indicates: whether respective HARQ-ACK feedback for the plurality of HARQ processes configured at the UE is of a TB level or a CBG level.

4. The method of claim 1, wherein the transmitter is a UE and the receiver is a BS in the wireless communication system, and

the HARQ retransmission information is one of:

a HARQ-ACK codebook including HARQ-ACK feedback for a first plurality of HARQ processes configured at the UE; or

A retransmission indicator comprising retransmission indications for a second plurality of HARQ processes configured at the UE.

5. The method of claim 4, wherein the TB/CBG indicator indicates:

whether respective HARQ-ACK feedback for the first plurality of HARQ processes configured at the UE is of TB level or CBG level, or

Each retransmission indication for the second plurality of HARQ processes configured at the UE is of a TB level or a CBG level.

6. The method of claim 4, wherein the retransmission indicator is included in an uplink grant that schedules a plurality of uplink data transmissions corresponding to the second plurality of HARQ processes configured at the UE.

7. The method of claim 1, wherein the first HARQ process is provided with HARQ-ACK feedback at TB level when:

all of the CBGs in the TB in the first HARQ process are correctly decoded;

no CBG in the TB in the first HARQ process is decoded correctly; or

The TB in the first HARQ process is not detected.

8. The method of claim 1, wherein the first HARQ process is provided with a retransmission indication at TB level when:

all CBGs in the TB in the first HARQ process are correctly decoded; or

No CBG in the TB in the first HARQ process is decoded correctly.

9. The method of claim 1, wherein the HARQ retransmission information comprises: HARQ-ACK feedback or retransmission indication for HARQ processes belonging to the same component carrier or different component carriers used by the transmitter and the receiver.

10. The method of claim 1, wherein an amount of HARQ processes in the HARQ retransmission information, each provided with HARQ-ACK feedback or retransmission indications at CBG level, is limited to less than or equal to a preconfigured number.

11. A receiver, the receiver comprising circuitry configured to:

receiving, from a transmitter in a wireless communication system, a Transport Block (TB) including one or more Code Block Groups (CBGs) corresponding to a first hybrid automatic repeat request (HARQ) process; and

transmitting a TB/CBG indicator and HARQ retransmission information, the HARQ retransmission information including HARQ acknowledgement (HARQ-ACK) feedback or a retransmission indication for the first HARQ process, the TB/CBG indicator indicating whether the HARQ-ACK feedback or the retransmission indication is of a TB level or a CBG level.

12. The receiver of claim 11, wherein the transmitter is a Base Station (BS) and the receiver is a User Equipment (UE) in the wireless communication system, and

the HARQ retransmission information is a HARQ-ACK codebook that includes HARQ-ACK feedback for a plurality of HARQ processes configured at the UE.

13. The receiver of claim 12, wherein the TB/CBG indicator indicates: whether respective HARQ-ACK feedback for the plurality of HARQ processes configured at the UE is of a TB level or a CBG level.

14. The receiver of claim 11, wherein the transmitter is a UE and the receiver is a BS in the wireless communication system, and

the HARQ retransmission information is one of:

a HARQ-ACK codebook including HARQ-ACK feedback for a first plurality of HARQ processes configured at the UE; or

A retransmission indicator comprising retransmission indications for a second plurality of HARQ processes configured at the UE.

15. The receiver of claim 14, wherein the TB/CBG indicator indicates:

whether respective HARQ-ACK feedback for the first plurality of HARQ processes configured at the UE is of TB level or CBG level, or

Each retransmission indication for the second plurality of HARQ processes configured at the UE is of a TB level or a CBG level.

16. A method, comprising:

receiving, at a receiver in a wireless communication system, a Transport Block (TB) including one or more Code Block Groups (CBGs) corresponding to a first hybrid automatic repeat request (HARQ) process from a transmitter; and

transmitting HARQ retransmission information from the receiver,

wherein the HARQ retransmission information includes a first field indicating a TB level positive Acknowledgement (ACK) or Negative Acknowledgement (NACK) for the first HARQ process, or indicating a new transmission or retransmission for the first HARQ process,

when the first field indicates a TB level NACK for the first HARQ process, the HARQ retransmission information further includes a second field indicating a CBG level ACK or NACK for the first HARQ process, an

When the first field indicates a retransmission for the first HARQ process, the HARQ retransmission information further includes a second field that provides a CBG level retransmission indication for the first HARQ process.

17. The method of claim 16, wherein the transmitter is a Base Station (BS) and the receiver is a User Equipment (UE) in the wireless communication system, and

the first field of the HARQ retransmission information indicates: TB-level ACKs or NACKs for a plurality of HARQ processes configured at the UE.

18. The method of claim 16, wherein the transmitter is a UE and the receiver is a BS in the wireless communication system, and

the first field of the HARQ retransmission information indicates: a TB-level ACK or NACK for a first plurality of HARQ processes configured at the UE, or a new transmission or retransmission for a TB-level of a second plurality of HARQ processes configured at the UE.

19. The method of claim 18, wherein the HARQ retransmission information is included in an uplink grant that schedules a plurality of uplink data transmissions corresponding to the second plurality of HARQ processes configured at the UE.

20. The method of claim 16, wherein the HARQ retransmission information comprises: a new transmission or retransmission at TB level or a TB level for HARQ processes belonging to the same component carrier or different component carriers used by the transmitter and the receiver.

Technical Field

The present invention relates to wireless communications, and more particularly to data retransmission techniques (e.g., hybrid automatic repeat request (HARQ) -related schemes).

Background

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

Transmissions over the wireless channel can be subject to errors due to variations in received signal quality. This change can be handled by employing a hybrid automatic repeat request (HARQ) scheme. HARQ is a combination of error correction coding and retransmission of erroneous data units. For example, after detecting an erroneous data unit transmitted from the transmitter, the receiver may request retransmission from the transmitter by providing HARQ feedback to the transmitter.

Disclosure of Invention

Aspects of the present invention provide a data retransmission method. The method may comprise the steps of: at a receiver in a wireless communication system, a transport block (TB: transport block) including a Code Block Group (CBG) corresponding to a first hybrid automatic repeat request (HARQ) process is received from a transmitter, and a TB/CBG indicator and HARQ retransmission information are transmitted from the receiver. The HARQ retransmission information comprises HARQ acknowledgement (HARQ-ACK) feedback or retransmission indication for the first HARQ process. The TB/CBG indicator indicates whether the HARQ-ACK feedback or the retransmission indication is of a TB level or a CBG level.

In an embodiment, the transmitter is a Base Station (BS) and the receiver is a User Equipment (UE) in the wireless communication system, and the HARQ retransmission information is a HARQ-ACK codebook comprising HARQ-ACK feedback for a plurality of HARQ processes configured at the UE. In an example, the TB/CBG indicator indicates: whether respective HARQ-ACK feedback for the plurality of HARQ processes configured at the UE is of a TB level or a CBG level.

In an embodiment, the transmitter is a UE and the receiver is a BS in the wireless communication system, and the HARQ retransmission information is one of: a HARQ-ACK codebook including HARQ-ACK feedback for a first plurality of HARQ processes configured at the UE; or a retransmission indicator comprising retransmission indications for a second plurality of HARQ processes configured at the UE including the first HARQ process. In an example, the TB/CBG indicator indicates whether respective HARQ-ACK feedback for the first plurality of HARQ processes configured at the UE is of TB level or CBG level, or whether respective retransmission for the second plurality of HARQ processes configured at the UE is of TB level or CBG level. In an example, the retransmission indicator is included in an uplink grant that schedules a plurality of uplink data transmissions corresponding to the second plurality of HARQ processes configured at the UE.

In an embodiment, the first HARQ process is provided with the HARQ-ACK feedback in TB level when: all CBGs in a TB of the first HARQ process are correctly decoded; no CBG in the TB in the first HARQ process is correctly decoded; or the TB in the first HARQ process is not detected.

In an embodiment, the first HARQ process is provided with the retransmission indication in TB level when: all CBGs in a TB in the first HARQ process are correctly decoded; or no CBG in the TB in the first HARQ process is decoded correctly.

In an embodiment, the HARQ retransmission information comprises: HARQ-ACK feedback or retransmission indication for HARQ processes belonging to the same component carrier (component carrier) or different component carriers used by the transmitter and the receiver. In an embodiment, the amount of HARQ processes in the HARQ retransmission information, each provided with HARQ-ACK feedback or retransmission indications at CBG level, is limited to be less than or equal to a preconfigured number.

Aspects of the invention provide a receiver including a circuit. The circuit is configured to: from a transmitter of the wireless communication system, a TB including a CBG corresponding to the first HARQ process is received, and a TB/CBG indicator and HARQ retransmission information are transmitted. The HARQ retransmission information includes: HARQ-ACK feedback or retransmission indication for the first HARQ process. The TB/CBG indicator indicates whether the HARQ-ACK feedback or retransmission indication is of a TB level or a CBG level.

Aspects of the present invention provide a data retransmission method. The method may comprise the steps of: at a receiver in a wireless communication system, a TB including a CBG corresponding to a first HARQ process is received from a transmitter, and HARQ retransmission information is transmitted from the receiver. The HARQ retransmission information includes a first field indicating a TB level ACK or NACK for the first HARQ process or indicating a new transmission or retransmission of the first HARQ process. When the first field indicates a TB level NACK for the first HARQ process, the HARQ retransmission information further includes a second field indicating a CBG level ACK or NACK for the first HARQ process. When the first field indicates retransmission, the HARQ retransmission information further includes a second field that provides a CBG level retransmission indication for the first HARQ process.

In an embodiment, the transmitter is a BS and the receiver is a UE in the wireless communication system. The first field of the HARQ retransmission information indicates: TB-level ACKs or NACKs for a plurality of HARQ processes configured at the UE. In an embodiment, the transmitter is a UE and the receiver is a BS in the wireless communication system. The first field of the HARQ retransmission information indicates: a TB-level ACK or NACK for a first plurality of HARQ processes configured at the UE, or a new transmission or retransmission for a TB-level of a second plurality of HARQ processes configured at the UE. The HARQ retransmission information may be included in an uplink grant that schedules a plurality of uplink data transmissions corresponding to the second plurality of HARQ processes configured at the UE.

In an embodiment, the HARQ retransmission information comprises: a TB-level ACK/NACK indication or a new transmission or retransmission at TB level for HARQ processes belonging to the same component carrier or different component carriers used by the transmitter and the receiver.

Drawings

Various embodiments of the present invention will be described in detail, by way of example, with reference to the following figures, wherein like reference numerals refer to like parts, and wherein:

fig. 1 illustrates a wireless communication system 100 according to some embodiments of the present invention;

fig. 2 illustrates an example of hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback and data retransmission operations based on a Code Block Group (CBG);

fig. 3A to 3B illustrate an example of how a CBG is formed in a Transport Block (TB);

fig. 4 shows an example of a CBG-based HARQ process 400 for data transmission in the downlink direction;

fig. 5 shows an example of a CBG-based HARQ process 500 for data transmission in the uplink direction;

fig. 6 shows another example of a CBG-based HARQ process 600 for data transmission in the uplink direction;

fig. 7 illustrates an example process 700 for TB-level one-shot HARQ-ACK feedback for uplink data transmission;

fig. 8 illustrates an example process 800 for TB level one time HARQ-ACK feedback for downlink data transmission;

fig. 9 illustrates a comparison between the size of a TB-level one-time HARQ-ACK codebook 910 and the size of a CBG-level one-time HARQ-ACK codebook 920;

fig. 10 shows an example of retransmission indication information 1000 carried in a single uplink grant scheduling multiple PUSCHs;

fig. 11 shows an example process 1100 for scheduling a single uplink grant for multiple PUSCHs, where a CBG level retransmission indication is included in the uplink grant;

fig. 12 shows an example of TB/CBG level hybrid HARQ-ACK feedback 1200 according to an embodiment of the invention;

fig. 13 shows a comparison between all CBG level HARQ-ACK feedback 1310 and hybrid HARQ-ACK feedback 1320;

fig. 14 shows a variation of hybrid HARQ-ACK feedback 1200;

FIG. 15 shows an example of a TB/CBG level hybrid retransmission indication 1500 according to an embodiment of the invention;

fig. 16 illustrates an example of a HARQ-ACK codebook 1610 according to an embodiment of the present invention;

fig. 17 shows an example of a retransmission indication 1710 according to an embodiment of the invention;

fig. 18 shows an example of a CBG-based HARQ retransmission process 1800 according to an embodiment of the present invention;

FIG. 19 shows an example of a retransmission process 1900 according to an embodiment of the invention; and

fig. 20 illustrates an example device 2000 in accordance with an embodiment of the present invention.

Detailed Description

Fig. 1 illustrates a wireless communication system 100 according to some embodiments of the present invention. System 100 may include a User Equipment (UE)110 and a Base Station (BS) 120. In some examples, the system 100 employs a fifth generation (5G) New Radio (NR) air interface developed by the third generation partnership project (3 GPP). In some examples, system 100 employs other wireless communication technologies developed by various standard development organizations. In some examples, system 100 employs non-standardized wireless communication technologies.

In some examples, BS120 may be a base station implementing a gNB node as specified in the 5G NR air interface standard developed by 3 GPP. In one example, BS120 may be configured to control one or more antenna arrays to form directional Tx or Rx beams for transmitting or receiving wireless signals. The UE110 may be a mobile phone, a laptop computer, a car-mounted mobile communication device, a utility meter (utility meter) fixed at a specific location, and the like. Similarly, in one example, UE110 may employ one or more antenna arrays to generate directional Tx or Rx beams for transmitting or receiving wireless signals. BS120 and UE110 may communicate with each other according to respective communication protocols according to an air interface between BS120 and UE 110.

In various examples, system 100 can employ a hybrid automatic repeat request (HARQ) scheme for data transmission or retransmission in the downlink or uplink direction. For example, the HARQ scheme may employ a HARQ entity at the MAC layer of the BS 120. The HARQ entity comprises a set of stop-and-wait (stop-and-wait) processes running in parallel. Each stop-and-wait process, referred to as a HARQ process, may transmit a Transport Block (TB) and stop and wait for HARQ acknowledgement (HARQ-ACK) information from UE 110. The HARQ-ACK information may be a single bit indicating positive Acknowledgement (ACK) or Negative Acknowledgement (NACK). If a NACK is received, retransmission of the TB may be performed.

At UE110, another HARQ entity including the same number of HARQ processes as at BS120 may be configured to receive the TBs from BS 120. Each HARQ process at UE110 corresponds to a corresponding HARQ process at BS 120. When each HARQ process receives a TB, UE110 attempts to decode the TB and generates an acknowledgement indicating whether the transport block was decoded correctly.

Similarly, HARQ entities or processes may be configured at UE110 and BS120 to implement a HARQ scheme for uplink data retransmission. For uplink data retransmission, for example, the HARQ feedback information may take the form of retransmission indication carried in an uplink scheduling grant (uplink grant). The retransmission indication provides enough information to inform UE110 of the retransmission of the TB in the uplink.

In some examples, system 100 may employ a block of code group (CBG) based HARQ scheme for data retransmission. For example, BS120 may transmit TBs partitioned into CBGs. UE110 may decode CBGs alone and provide harq-ACK feedback for TBs at the CBG level. Based on the CBG level HARQ-ACK feedback, the BS120 may retransmit only the negatively acknowledged CBG, rather than the entire TB. As a result, data retransmission may be more efficient in terms of radio resource consumption, especially for large size TBs.

However, when using the CBG level HARQ scheme, the size of the corresponding HARQ-ACK feedback (or retransmission indication of uplink data transmission) for downlink data transmission may be significantly increased compared to the HARQ scheme having TB level HARQ feedback information. Fig. 1 shows such an example of downlink data transmission. As shown, BS120 may perform multiple downlink data transmissions to transmit TBs 131 and 134 using HARQ processes #0 through #3, respectively. The TBs in each downlink transmission may be divided into 4 CBGs. The multiple downlink transmissions may span multiple time slots in an Orthogonal Frequency Division Multiplexing (OFDM) resource grid and span multiple component carriers.

In response, UE110 may provide HARQ feedback information 160 at the CBG level. As an option, HARQ feedback information 160 may be a HARQ-ACK codebook 140 including CBG level HARQ-ACK feedbacks 141-144 for the respective HARQ processes #0 to # 3. As shown, the CBG level HARQ-ACK codebook 140 may have a size of 16 bits.

In some examples, a one-shot HARQ-ACK feedback scheme (one-shot HARQ-ACK feedback) is employed in which the latest status of all HARQ processes configured at UE110 (e.g., pending or reported HARQ-ACK reports) is reported to BS120 in one HARQ-ACK feedback. The total size of the reported payload is 128 bits for a configuration of 8 CBGs per TB and 16 HARQ processes.

Thus, in some embodiments, when using a CBG level HARQ scheme, a hybrid HARQ feedback mechanism is employed to compress HARQ feedback information. For example, as shown in HARQ-ACK codebook 140, HARQ-ACK feedback 141 for HARQ process #0 includes 4 ACKs, which 4 ACKs indicate that all CBGs in TB 131 are decoded correctly. Therefore, TB level HARQ-ACK feedback may be used instead of CBG level HARQ-ACK feedback. Specifically, one bit indicating ACK may be used in HARQ-ACK codebook 140 instead of 4 bits indicating 4 ACKs for HARQ feedback corresponding to HARQ process 141.

Similarly, HARQ-ACK feedback 142 for HARQ process #1 includes 4 NACKs, which 4 NACKs indicate that none of the CBGs in TB 132 were detected or correctly decoded. Therefore, TB level HARQ-ACK feedback (1-bit NACK) may be used instead of CBG level HARQ-ACK feedback including 4-bit NACK. For HARQ processes #2 and #3, CBG level feedback may still be maintained since HARQ-ACK feedback 143 through 144 both contain correctly decoded CBGs or incorrectly decoded CBGs. In this way, the size of the HARQ-ACK codebook 140 may be reduced from 16 bits to 10 bits, resulting in a data compression ratio of 16: 10.

To indicate whether to provide HARQ-ACK feedback for HARQ processes at the TB level or at the CBG level, a TB/CBG level indicator 150 may be introduced in HARQ information 160. As shown, the TB/CBG level indicator values for HARQ processes #0 and #1 are set to 0 to indicate TB level HARQ-ACK feedback, and for HARQ processes #2 and #3, the respective TB/CBG level indicator values are set to 1 to indicate CBG level HARQ-ACK feedback.

The TB and hybrid HARQ feedback mechanisms described above may also be applied to data transmission in the uplink direction. For example, when a HARQ-ACK codebook is transmitted from the BS120, or when retransmission indicators for multiple HARQ processes are provided in a grant for scheduling multiple Physical Uplink Shared Channels (PUSCHs), a hybrid HARQ feedback mechanism may be employed to compress the corresponding HARQ feedback information. The corresponding HARQ feedback information may be HARQ-ACK information in a HARQ-ACK codebook or retransmission indication information of a retransmission indicator in an uplink scheduling grant (uplink grant).

Fig. 2 shows an example of CBG-based HARQ-ACK feedback and data retransmission operations. TB 210 is transmitted from a transmitter (e.g., BS120) to a receiver (e.g., UE 110). TB 210 is divided into 7 CBs from CB #0 to CB #6, the 7 CBs being organized into 4 CBGs from CBG #0 to CBG # 3. Decoding of CB #3 fails during reception of TB 210 by UE 110. Thus, UE110 may send CBG level ACK/NACK feedback [ a na ], where a represents an ACK bit and N represents a NACK bit. The ACK or NACK bits correspond to 4 CBGs from CBG #0 to CBG #3, respectively. In response, the BS120 may perform CBG level retransmission in which CBG #1 is retransmitted. In some other examples, TB 120 may be transmitted from UE110 to BS120, CBG level ACK/NACK feedback [ a na a ] may be provided in the form of a retransmission indicator, e.g., [ 0100 ] in an uplink grant transmitted from BS120 to UE110, where "0" indicates that the corresponding CBG should not be retransmitted and "1" indicates that the corresponding CBG should be retransmitted.

As shown, a more refined ACK/NACK feedback based on CBG (or a more refined retransmission indication in the uplink grant) may be used to provide HARQ ACK/NACK feedback compared to TB-based HARQ-ACK feedback. Therefore, only CBGs with failed CBs are transmitted, not the entire TBs, which improves spectral efficiency.

In contrast, in an example in which the CBG-based HARQ scheme of fig. 2 is not employed, if Code Block (CB) decoding fails when the TB is decoded, the entire TB must be retransmitted. Such TB-based HARQ may lead to performance degradation especially in case that TB size is large (e.g., TB contains many CBs), severe time-varying interference, ultra-reliable low-latency communication (URLLC) preempts ongoing transmission of enhanced mobile broadband (eMMB), or interference from hidden nodes in NR unlicensed band operation.

Fig. 3A to 3B show examples of how a CBG is formed in a TB. In an embodiment, the maximum number of CBGs in a TB (denoted by N) may be provided by higher layer signaling (e.g., Radio Resource Control (RRC) signaling) or system information broadcast from BS120 to UE110, so that BS120 and UE110 may have a common understanding of the maximum number of CBGs per TB. In one example, N may be 2, 4, 6, or 8 in different configurations.

The determination of the TB size and the number of CBs in a TB (denoted by C) may be independent of the maximum number N of CBGs in a TB. For example, the size of the TB may be determined based on the allocated radio resources and a corresponding Modulation and Coding Scheme (MCS). When a TB having a certain size is received from a MAC layer at a physical layer, the TB, including an additional Cyclic Redundancy Check (CRC), may be divided into a plurality of CBs (e.g., tens or hundreds) to match a code size of a channel encoder (e.g., a Low Density Parity Check (LDPC) encoder) for encoding the CBs. The CBs, each with an attached CRC, may then be fed into a channel encoder and the resulting bits concatenated to form an encoded TB.

The number C of CBs in a TB may be grouped into a number of CBGs having a number Min (N, C). In the example of fig. 3A, there are 4 CBGs (N ═ 4) in the TB, and 3 CBs (CB #0 to CB #2) are generated (C ═ 3). Thus, there are 3 CBGs in TB, each CBG containing one CB. In the example of fig. 3B, there are still 4 CBGs in the TB (N ═ 4), however, 7 CBs (CB #0 to CB #6) are generated. Thus, there are 4 CBGs in a corresponding TB, each CBG including one or two CBs.

Fig. 4 shows an example of a CBG-based HARQ process 400 for data transmission in the downlink direction. The process 400 may include 4 steps from S401 to S404, and the process 400 is performed by the BS420 and the UE 410. The BS420 may configure the UE410 with a maximum number of CBGs per TB, which is 4 in the example of fig. 4, e.g., through RRC signaling.

At S401, the BS420 transmits a first TB431 (this is an initial transmission). TB431 may include CB #0 to CB #6 organized into CBG #0 to CBG # 3. After channel coding and rate matching, TB431 may be carried in a first Physical Downlink Shared Channel (PDSCH). First Downlink Control Information (DCI) scheduling an initial transmission on a first PDSCH may be carried in a first physical control channel (PDCCH) accompanying the PDSCH. The first DCI of the initial transmission may include a first CBG transmission indicator (CBGTI) indicating which CBGs are present in the transmitted TBs 431, for example. However, the UE410 may ignore the first CBGTI and assume that all CBGs are present in the initial transmission.

UE410 decodes the first PDCCH to obtain the first DCI and then decodes the first PDSCH to obtain decoded TB432, which decoded TB432 is a decoded version of TB 431. As an example, the decoding of CB #3 may fail, while the decoding of the other CBs #0 to #2 and CB #4 to #6 is successful. For example, the CRCs attached to the respective CBs may be checked to determine whether the respective CBs are correctly decoded. The UE410 may accordingly generate a first HARQ-ACK feedback comprising bits a na. The first HARQ-ACK feedback indicates that CBGs #0, #2, and #3 were correctly received, but CBG #1 was not correctly received.

At S402, the UE410 may transmit a first HARQ-ACK feedback including a bit [ AN a ] to the BS420, e.g., using the resources indicated by the first DCI. For example, the first HARQ-ACK may be carried in a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH).

In response to receiving the first HARQ-ACK feedback, the BS420 may retransmit CBG #1 carried in the second TB441 at S403. A second CBGTI carried in the second DCI may accompany (acontany) the second TB441 to indicate which CBGs are present or absent in the second TB 441. For example, the second CBGTI may still include 4 bits [ 0100 ], where the 4 bits indicate that CBG #1 (second CBG) in the initial TB431 is carried in the second TB441, and the first CBG, the third CBG, and the fourth CBG in the initial TB431 are not present in the second TB 441. The second TB441 may be carried in the second PDSCH, while the second DCI may be carried in the second PDCCH.

Based on the second CBGTI, the UE410 may determine that CBG #1 in the initial TB431 is being retransmitted without retransmitting CBGs #0, #2, and #3, and may combine the decoded CBG #1 in the decoded TB 442 with the previously consecutively received CBGs #0, #2, and #3 to form a TB in the completely decoded initial TB 431.

At S404, the UE410 may provide the second HARQ-ACK feedback to the BS120 since the retransmitted data has been continuously decoded. The second HARQ-ACK feedback may include a bit a to indicate that all CBGs of the initial transmission at S401 have been correctly received. The process may thereafter terminate.

Fig. 5 shows an example of a CBG-based HARQ process 500 for data transmission in the uplink direction. The process 500 may include steps from S501 to S504, and the process 500 is performed by the BS 520 and the UE 510. Similarly, the BS 520 may configure the UE 510 with a maximum number of CBGs per TB, which is 4 in fig. 5.

At S501, the BS 520 may transmit a first uplink scheduling grant (uplink grant) to the UE 510. For example, a first uplink grant is carried in the first DCI, and an uplink resource of the UE 510 is designated to transmit the TB 531. The first uplink grant may carry a first CBGTI indicating which CBGs to send in TB 531. Since the transmission of TB531 will be the initial transmission of TB531, UE 510 may ignore the first CBGTI and assume that all CBGs are to be sent in the initial transmission.

The UE 510 may prepare the TB531 based on the first uplink grant from the BS 520. As an example, TB531 includes CBs #0 to #6 organized into CBGs #0 to # 3.

At S502, the UE 510 transmits the TB531, for example, carried in the first PUSCH, as an initial transmission to the BS 520. The BS 520 decodes the first PUSCH from the UE 510 to obtain a decoded TB 532. As an example, decoding of CB #3 fails and decoding of other CBs in TB 532 is successful. Accordingly, the BS 520 may determine to retransmit CBG # 1.

At S503, the BS 520 transmits a second uplink grant in the second DCI to schedule the second uplink transmission. In particular, the second uplink grant may include a second CBGTI to indicate which CBGs in the initial TB531 to retransmit. For example, the second CBGTI from BS 520 may include bits [ 0100 ] that each correspond to a CBG in the initial TB 531. "0" indicates that the corresponding CBG should not be resent, and "1" indicates that the corresponding CBG should be resent.

Based on the second CBGTI received from the BS 520, the UE 510 may prepare a second TB 541 including CBG #1 in the initial TB 531.

At S504, the UE 510 may send a second TB 541 carried in a second PUSCH (which is a partial retransmission of the initial TB 531) to the BS 520. The BS120 decodes the second PUSCH from the UE 510, and obtains a decoded TB 542 including CBG #1 in the initial TB 531. The process 500 may then terminate.

Fig. 6 shows another example of a CBG-based HARQ process 600 for data transmission in the uplink direction. In the process 600, a pair of specific HARQ processes with ID # n at the UE 610 and the BS 620 is depicted. Also, the operation of a New Data Indicator (NDI) carried in an uplink grant is described. The process 600 may include steps from S601 to S604, and the process 600 is performed by the UE 610 and the BS 620.

At S601, the BS 620 transmits a first uplink grant (UL grant #1) to the UE 610. UL grant #1 may include: a first field carrying a HARQ process ID (e.g., # n), a second field carrying a first NDI, and a third field carrying a first CBGTI. Since UL grant #1 is used to schedule initial data transmission, the first NDI may have a "toggled" state compared to the state of a previous NDI corresponding to HARQ process # n in a UL grant preceding UL grant # 1. Based on UL grant #1, UE 610 may determine that UL grant #1 schedules an initial data transmission to be performed by HARQ process # n. The first CBGTI may be ignored and the UE 610 may transmit all CBGs in the TB 631 to be transmitted.

At S602, the UE 610 may perform initial data transmission using HARQ process # n to transmit a TB 631 through a first PUSCH. As shown, TB 631 may include 4 CBGs from CBG #1 to CBG # 4. The BS 620 performs decoding to obtain a decoded TB 632 of the initial TB 631. CBG #2 and #3 failed to receive.

At S603, the BS 620 may accordingly transmit a second uplink grant (UL grant #2) to schedule retransmission of the failed CBGs #2 and # 3. Specifically, UL grant #2 may include: a first field indicating the same HARQ process ID (# n), as in UL grant # 1. UL grant #2 may also include a second field indicating a second NDI having a "not toggled" state compared to the first NDI in UL grant # 1. The "not switched" status indicates that retransmission is to be performed using the resources specified by UL grant # 2. UL grant #2 may also include a third field indicating a second CBGTI to indicate which CBGs to retransmit. The second CBGTI may have bits [ 0110 ] corresponding to the decoding result of the decoded TB 632.

Based on UL grant #2, the UE 610 may determine to retransmit CBGs #2 and #3 in the initial TB 631.

At S604, the UE 610 retransmits the second TB 633 including CBGs #2 and #3 with the HARQ process # n indicated by the UL grant #2 through the second PUSCH. Thereafter, the process 600 terminates.

Fig. 7 shows an example process 700 for TB-level one-time HARQ-ACK feedback for uplink data transmission. The process 700 includes steps S701 and S702, and the process 700 is performed by the UE 710 and the BS 720.

In S701, the UE 710 performs multiple initial transmissions of TB 731-734 by using multiple HARQ processes #3, #1, #6, and #2, respectively, over component carrier CC # x. The initial transmission of TB 731-. For example, the transmission of TB 731-.

BS 720 performs reception using HARQ processes #3, #1, #6, and #2, respectively, to obtain decoded TB 741-744 corresponding to initial TB 731-734. By way of example, TB 742-.

At S702, the BS 720 may perform HARQ-ACK feedback once. In one-time HARQ-ACK feedback, a HARQ-ACK codebook 751 can be transmitted that includes HARQ-ACK feedback for multiple or all configured HARQ processes at the UE 710. For example, there may be 8 HARQ processes from #0 to #7 configured at the UE 710. HARQ-ACK codebook 751 may include 8 bits (both ACK or NACK) corresponding to 8 HARQ processes #0 to # 7. In one example, the latest status of each HARQ process is reported in a one-time HARQ-ACK codebook. For example, ACK of HARQ processes (e.g., HARQ processes #3 and #2) that correctly decode the TB is reported, while NACK of HARQ processes (e.g., HARQ processes #1, #6, and #7) that inaccurately decode the TB or HARQ processes (e.g., HARQ processes #0, #4, and #5) that do not detect the TB during a preconfigured period before one HARQ-ACK feedback is reported. In one example, the one-time HARQ-ACK codebook 751 is carried in Downlink Feedback Information (DFI) in the PDCCH.

As an example, the UE 710 and the BS 720 may operate on unlicensed spectrum, and the frequency of the component carrier CC # x may be shared with hidden devices (e.g., Wi-Fi receivers or transmitters) and not always available. When component carrier CC # x is available, e.g., after a listen-before-talk (LBT) access procedure, BS 720 may determine to provide HARQ-ACK feedback to UE 710 once for this opportunity.

In response to the one-time HARQ-ACK feedback, in one example, the UE 710 may or may not perform the retransmission. If retransmission is performed, the process provided with NACK may perform retransmission using PUSCH resources scheduled by the uplink grant or preconfigured by the BS 720 without providing any uplink grant. Process 700 may then terminate.

Fig. 8 shows an example process 800 for TB-level one-time HARQ-ACK feedback for downlink data transmission. The process 800 may include steps from S801 to S803, and the process 800 is performed by the UE 810 and the BS 820.

At S801, BS820 may perform initial transmission of TB 831-834 by using HARQ processes #3, #1, #6, and #2 through component carrier CC # x, respectively. UE 810 may perform reception using HARQ processes #3, #1, #6, and #2 to obtain decoded TB 841-844 corresponding to initial TB 831-834, respectively. Decoding of TBs 842 and 843 may fail. TB 831-834 may be transmitted in different time slots.

At S802, the BS820 may send a request for one HARQ-ACK feedback for all HARQ processes configured at the UE 810. The request may be carried in DCI in PDCCH. For example, the HARQ-ACK feedback transmission opportunity is temporarily unavailable (e.g., when operating over the unlicensed spectrum), or the BS820 has lost transmission of HARQ-ACK feedback from the UE 810 due to severe interference. BS820 will have no HARQ-ACK process available for downlink data transmission. Accordingly, the BS820 may determine to send a request for one HARQ-ACK feedback to trigger the UE 810 to provide the required HARQ-ACK feedback. The request may be accompanied by resource scheduling information (e.g., carried in an uplink scheduling grant (uplink grant) or a downlink scheduling assignment) for scheduling resources for one HARQ-ACK feedback. The resource scheduling information may be carried in the same DCI as the request for one HARQ-ACK feedback.

In response to receiving the request for one-time HARQ-ACK feedback, the UE 810 performs TB-level one-time HARQ-ACK feedback S803. The HARQ-ACK codebook 851, including ACKs or NACKs of all configured HARQ processes from #0 to #7, may be included in Uplink Control Information (UCI) and transmitted through PUCCH resources. In other examples, the HARQ codebook may be carried in the PUSCH. In response to receiving the UCI at S803, the BS820 may perform data retransmission as indicated by one HARQ-ACK feedback at S803 at a later stage. Process 800 may then terminate.

Fig. 9 shows a comparison between the size of the TB-level one-time HARQ-ACK codebook 910 and the size of the CBG-level one-time HARQ-ACK codebook 920. The two codebooks 910 and 920 may include: TB level or CBG level HARQ-ACK feedback for 16 HARQ processes from #0 to #15 configured for component carrier CC # x. For codebook 920, a CBG-based HARQ scheme is employed, and the maximum number of CBGs per TB is equal to 8. Thus, TB-level one-time HARQ-ACK codebook 910 may include 16 bits (ACK or NACK) for 16 HARQ processes, while CBG-level one-time HARQ-ACK codebook 920 may include 128 bits, and each HARQ process has 8 bits of ACK or NACK for a corresponding 8 CBGs.

It can be seen that the size of codebook 920 can be enlarged with the maximum number of CBGs per TB (e.g., 2, 4, 6, or 8 CBGs per TB) or the number of HARQ processes increasing, which results in a larger payload size of DFI or UCI carrying one HARQ-ACK feedback. Therefore, a compression scheme for reducing the size of the CBG level one-time HARQ-ACK feedback codebook is desired.

Thus, in some embodiments, hybrid TB level or CBG level HARQ-ACK feedback is included in the one-time HARQ-ACK feedback codebook at the same time. CBG level HARQ feedback is not required for CBGs that are not detected, CBGs that are not decoded correctly, or HARQ processes that have all CBGs decoded correctly. Conversely, TB level HARQ feedback may be used. In contrast, CBG level HARQ feedback may be employed for HARQ processes with both failed CBGs and successful CBGs. In this way, the total size of the one-time HARQ feedback codebook may be reduced.

Fig. 10 shows an example of retransmission indication information 1000 carried in a single uplink grant scheduling multiple PUSCHs. For example, the uplink grant schedules 8 PUSCHs for 8 uplink data transmissions or retransmissions with 8 HARQ processes from # n to # n +7 at the UE. For example, a HARQ process ID, an NDI, and a CBGTI may be included in the uplink grant for each HARQ process. When a maximum of 8 CBGs are configured in TBs, each CBGTI may include 8 bits corresponding to a corresponding CBG in a corresponding TB. Thus, the CBGTI bit size may be 64 bits. It can be seen that the size of the CBGTI bits may be proportional to the maximum number of CBGs configured by TB and the number of PUSCHs that may be scheduled by a single uplink grant, which similarly results in a larger payload size of DCI carrying uplink grants scheduling multiple PUSCHs. Therefore, this compression scheme is desirable to reduce the size of the CBGTI bits used for retransmission indications.

As shown, HARQ processes # n, # n +1, and # n +3 all have a "handed over" NDI indicating initial data transmission for each respective HARQ process. In contrast, HARQ processes # n +2 and # n +4 to # n +7 all have an "unswitched" NDI indicating a retransmission of data for each respective HARQ process. In addition, the CBGTI of each handed-over NDI may indicate which CBGs in the corresponding initial TB are to be retransmitted.

Similarly, mixed TB level and CBG level retransmission indications may be included in the retransmission indication information 1000. For example, a CBG level retransmission indication is not needed for HARQ processes that do not decode correctly for CBGs (e.g., HARQ process # n +6 in fig. 10) or HARQ processes with initial transmission (e.g., HARQ process # n). In contrast, CBG level retransmission indications may be used for HARQ processes with both correctly decoded CBGs and incorrectly decoded CBGs.

Fig. 11 shows an example process 1100 for scheduling a single uplink grant for multiple PUSCHs, where a CBG level retransmission indication is included in the uplink grant. The process 1100 includes steps S1101 and S1102, and the process 1100 is performed by the UE1110 and the BS 1120.

At S1101, the UE1110 may perform initial transmission of a set of TBs 1131-1134 by using HARQ processes #3, #1, #6, and #2 through component carrier CC # x, respectively. BS 1120 performs reception to obtain decoded TB 1141 and 1144. The initial transmission of the TBs 1131-1134 may be based on the CBG level. Decoded TBs 1142 and 1143 may include incorrectly decoded CBGs.

At S1102, the BS 1120 may transmit an uplink grant scheduling multiple PUSCHs. For example, the uplink grant may indicate a number of HARQ processes from # n to # n +7 for a number of uplink transmissions (initial transmissions or retransmissions) over the scheduled PUSCH. As an example, a maximum of 8 CBGs may be carried in one TB by the configuration of the BS 1120. Thus, the CBGTI field in the uplink grant may include 64 bits (for 8 HARQ processes, each HARQ process corresponding to 8 CBGs). HARQ processes from # n to # n +7 may include HARQ processes #1 and #6 corresponding to failed TBs 1142 and 1143. The corresponding CBGTI bits may indicate which CBGs of the initial TBs 1132 and 1133 need to be retransmitted. In response to receiving the uplink grant at S1102, the UE1110 may then perform data retransmission or initial data transmission according to the indication of the CBGTI field in the uplink grant at S1102. Thereafter, process 1100 may terminate.

Fig. 12 shows an example of TB/CBG level hybrid HARQ-ACK feedback 1200 according to an embodiment of the invention. For example, the receiver receives a TB from the transmitter. Enabling CBG level retransmissions between the receiver and the transmitter. A maximum of 8 CBGs per TB is configured. The hybrid HARQ-ACK feedback 1200 may be carried in DFI, UCI, or PUSCH and sent from the receiver to the transmitter.

Hybrid HARQ-ACK feedback 1200 may include a TB/CBG indicator 1220 and a HARQ-ACK codebook 1230. In the example of fig. 12, the HARQ-ACK codebook 1230 includes HARQ-ACK feedbacks 1231-1238 for all HARQ processes #0 to #7 configured at the receiver, and thus is a codebook of one-time HARQ-ACK feedbacks. In other examples, HARQ-ACK codebook 1230 may include a subset of all HARQ processes configured at the receiver.

The TB/CBG indicator 1220 may be a bitmap field including bits S0 through S7. Each bit S0 through S7 corresponds to one of HARQ processes #0 through # 7. The bits S0 to S7 indicate whether the respective HARQ processes #0 to #7 are provided with respective HARQ-ACK feedbacks 1231 and 1238 of the TB level or the respective HARQ-ACK feedbacks 1231 and 1238 of the CBG level. For example, bits S0, S2 to S4, and S7 indicate that HARQ-ACK feedback for HARQ processes #0, #2 to #4, and #7 is TB-level, and bits S1, S5, and S6 indicate that HARQ-ACK feedback for HARQ processes #1, #5, and #6 is CBG-level. As shown, the number of HARQ-ACK processes with CBG level HARQ-ACK feedback in hybrid HARQ-ACK codebook 1200 is reduced from 8 to 3 compared to a HARQ-ACK codebook with pure CBG level HARQ-ACK feedback.

In other examples, HARQ-ACK feedback 1231-1238 in HARQ-ACK codebook 1230 may be all TB levels or all CBG levels depending on whether a correctly decoded CBG or an incorrectly decoded CBG in the respective HARQ-ACK feedback.

In some examples, to limit the size of hybrid HARQ-ACK feedback 1200, the amount of HARQ processes with CBG level HARQ-ACK feedback is limited to be less than or equal to a preconfigured number. For example, the maximum number of HARQ processes with CBG level HARQ feedback is set to 4. If the maximum number is reached, the additional HARQ processes with both failed and successful CBGs can be limited to have TB level HARQ-ACK feedback. In this way, the payload size corresponding to the hybrid HARQ-ACK feedback 1200 may be controlled to be below the limit.

In addition, when a carrier aggregation scheme is employed, the HARQ processes in the hybrid HARQ-ACK feedback 1200 may belong to the same component carrier or different component carriers. For example, the HARQ-ACK codebook 1230 may include one HARQ-ACK feedback for HARQ-ACK processes belonging to multiple component carriers.

Fig. 13 shows a comparison between all CBG level HARQ-ACK feedback 1310 and hybrid HARQ-ACK feedback 1320. As shown, CBG level HARQ-ACK feedback 1310 may be a HARQ-ACK codebook 1311, where each HARQ process #0 through #7 includes 8 ACK/NACK bits. Each ACK/NACK bit corresponds to a CBG in the TB. Hybrid HARQ-ACK feedback 1320 may include a TB/CBG indicator (bitmap field) 1321 and a HARQ-ACK codebook 1322.

As shown in CBG level HARQ-ACK feedback 1310, all CBGs in the TB are correctly decoded and 8 ACK bits are provided for HARQ processes #0, #1, and # 6. In contrast, in hybrid HARQ-ACK feedback 1320, HARQ-ACK feedback for HARQ processes #0, #1, and #6 is converted to TB level and all are set with a single ACK bit. Similarly, the CBG level HARQ-ACK feedback for HARQ-ACK process #3 in CBG level HARQ-ACK feedback 1310 is converted to TB level in hybrid HARQ-ACK feedback 1320 and a NACK bit is set.

In particular, for HARQ process #7 with both correctly decoded CBGs and incorrectly decoded CBGs, the CBG level HARQ-ACK feedback is also converted to TB level to meet the limit of the maximum number of HARQ processes with CBG level HARQ-ACK feedback. For the remaining HARQ processes #2, #4, and #5, 8-bit CBG level HARQ-ACK feedback is maintained between CBG level HARQ-ACK feedback 1310 and hybrid HARQ-ACK feedback 1320 to facilitate CBG-based data retransmission.

Thus, TB/CBG indicator 1321 provides bit 0 to indicate that HARQ-ACK processes #0, #1, #3, #6, and #7 are provided with TB level HARQ-ACK feedback; and bit 1 is provided to indicate that HARQ-ACK processes #2, #4, and #5 are provided with CBG level HARQ-ACK feedback.

As shown in fig. 13, the size of the HARQ-ACK feedback is reduced from 64 bits in CBG level HARQ-ACK feedback 1310 to 37 bits in the hybrid HARQ-ACK feedback.

Fig. 14 shows a variation of hybrid HARQ-ACK feedback 1200. As shown, hybrid HARQ-ACK feedback 1200 is included in a HARQ-ACK codebook 1400 that includes a first field and a second field. The first field corresponds to a TB/CBG indicator 1220 and the second field corresponds to a HARQ-ACK codebook 1230.

Fig. 15 shows an example of a TB/CBG level hybrid retransmission indication 1500 according to an embodiment of the present invention. For example, DCI (including an uplink grant) scheduling a plurality of PUSCHs #0 to #7 may be transmitted from the BS to the UE. The plurality of PUSCHs #0 to #7 correspond to a plurality of HARQ processes # n to # n + 7. The DCI may carry information of the hybrid retransmission indication 1500. The hybrid retransmit indication 1500 may include a TB/CBG indicator 1511 and a retransmit indicator 1512.

The TB/CBG indicator 1511 may indicate: the retransmission indication corresponding to each of the HARQ processes # n to # n +7 is of TB level or CBG level. For example, TB/CBG indicator 1511 may include bits 0 or 1, each bit corresponding to one of HARQ processes # n to # n + 7. For HARQ processes # n, # n +1, # n +3, and # n +6, bit 0 is set to indicate that the respective retransmission indication is TB level, and for HARQ processes # n +2, # n +4, # n +5, and # n +7, bit 1 is set to indicate that the respective retransmission indication is CBG level. In particular, for HARQ processes with initial transmission or HARQ processes with all CBGs in the corresponding TB to be retransmitted, bit 1 is set to indicate that the corresponding retransmission indication is TB level.

Retransmission indicator 1512 may include a retransmission indication (1 bit or 8 bits) for each HARQ process. Each retransmission indicator may indicate whether a respective transmission in a respective PUSCH is an initial transmission or a retransmission. For example, a retransmission indication of 0 for HARQ processes # n, # n +1, and # n +3 indicates an initial transmission, and a retransmission indication of 1 (for HARQ process # n +6) or 8-bit retransmission indication (for HARQ processes # n +2, # n +4, and # n +5) indicates a retransmission.

Compared to the retransmission indication information 1000 in fig. 10 (reproduced as retransmission indication information 1501 in fig. 15), the NDI and CBGTI in fig. 10 are replaced with a TB/CBG indicator 1511 and a retransmission indicator 1512. The size of the retransmission indication information is reduced from 72 bits in the CBG level retransmission indication information 1000 to 44 bits in the hybrid retransmission indication 1500.

Similar to the hybrid HARQ-ACK feedback 1200 in fig. 12, the retransmission indications for the individual HARQ processes in fig. 15 may be all TB level or all CBG level. The maximum number of HARQ processes with CBG level retransmission indications may be configured to control the size of the hybrid retransmission indication 1500. The HARQ processes indicated in the DCI scheduling multiple PUSCHs may belong to the same component carrier or different component carriers.

Fig. 16 shows an example of a HARQ-ACK codebook 1610 according to an embodiment of the present invention. For example, the receiver receives a TB from the transmitter. 8 HARQ processes #0 to #7 are configured at the receiver. Enabling CBG level retransmissions between the receiver and the transmitter. A maximum of 8 CBGs per TB is configured. The hybrid HARQ-ACK codebook 1610 may be carried in DFI, UCI, or PUSCH and transmitted from a receiver to a transmitter.

The HARQ-ACK codebook 1610 may include a first field 1620 and a second field 1630. The first field 1620 may be a bitmap field including bits S0 through S7. Each bit S0 through S7 corresponds to one of HARQ processes #0 through # 7. The first field 1620 may indicate ACK or NACK of the respective HARQ processes #0 to #7 at TB level with the respective bits S0 to S7. For example, all CBGs in the corresponding TB have been correctly received for HARQ processes #0, #2 through #4, and # 7. Accordingly, a TB level ACK for each HARQ process #0, #2 through #4, or #7 may be set in the first field 1620 to indicate that the entire TB has been correctly decoded.

In contrast, for HARQ processes #1, #5, and #6, a TB level NACK is set in the first field 1620 to indicate that at least one CBG has not been correctly decoded for the corresponding HARQ process or that the corresponding TB has been lost (not detected). In particular, in the second field, CBG level ACKs or NACKs 1632, 1636, and 1637 are also set for HARQ processes #1, #5, and #6 having TB level NACK in the first field 1620.

In the example of fig. 13, HARQ process #3 has 8 failed CBGs in HARQ-ACK codebook 1311 and a TB level NACK is used in hybrid HARQ-ACK codebook 1322. Compared to the example of fig. 13, in fig. 16, even if all CBGs in the corresponding HARQ process fail, all HARQ processes having the failed CBG may be all provided with CBG level ACK or NACK. In addition, in fig. 16, no bit is carried in the second field 1630 for HARQ processes with TB level ACK.

The TB-level ACK/NACK bits S0 through S7 in the first field 1620 may all be ACKs or NACKs depending on whether the corresponding CBGs are all correctly received. In addition, HARQ processes #0 to #7 indicated in the HARQ-ACK codebook 1610 may belong to the same component carrier or different component carriers.

Fig. 17 shows an example of a retransmission indication 1710 according to an embodiment of the present invention. For example, DCI (including an uplink grant) scheduling a plurality of PUSCHs may be transmitted from the BS to the UE. The plurality of PUSCHs correspond to the plurality of HARQ processes #0 to # 7. The DCI may carry information of the retransmission indication 1710. Retransmission indication 1710 may include a first field 1720 and a second field 1730.

The first field 1720 may be a bitmap field including bits S0 through S7. Each bit S0 through S7 corresponds to one of HARQ processes #0 through # 7. The first field 1720 may indicate whether a transmission corresponding to each HARQ process #0 to #7 is a new (initial) transmission or a retransmission using respective bits S0 to S7. For example, new transmissions are indicated in the first field 1720 for HARQ processes #0, #2 through #4, and #7, while retransmissions are indicated in the first field 1720 for HARQ processes #1, #5, and # 6. In addition, CBG level retransmission indications 1732, 1736, and 1737 are set in the second field for HARQ processes with retransmission indications. In one example, each bit in the first field may be an NDI bit corresponding to each HARQ process.

In the example of fig. 15, HARQ process # n +6 has 8 failed CBGs, and a 1-bit TB level retransmission indication is set in retransmission indicator 1512. In contrast, in fig. 17, for a HARQ process having 8 CBGs that failed, a CBG-level retransmission indication is set in the second field 1730 instead of a TB-level retransmission indication. In addition, in fig. 17, no bits are carried in the second field 1730 for HARQ processes with new transmissions in the first field 1720.

The new transmissions or retransmissions indicated in the first field 1620 may all be new transmissions or retransmissions depending on whether the corresponding CBGs were all correctly received. In addition, HARQ processes #0 to #7 indicated in the retransmission indication 1710 may belong to the same component carrier or different component carriers.

Fig. 18 shows an example of a CBG-based HARQ retransmission process 1800 according to an embodiment of the present invention. Process 1800 employs the TB/CBG level hybrid HARQ feedback mechanism of the present invention. Process 1800 may be performed at a receiver that receives a TB from a sender. The transmitter and receiver are part of a wireless communication network. Process 1800 may begin at S1801 and proceed to S1810.

At S1810, a TB including a CBG may be received at a receiver. The reception of the TB may be performed by the first HARQ process.

At S1820, hybrid HARQ feedback information may be transmitted from the receiver. The hybrid HARQ feedback information may include a TB/CBG indicator and HARQ retransmission information. The HARQ retransmission information may be a HARQ-ACK codebook, or retransmission indicators for a number of HARQ processes configured at the receiver. For example, the HARQ-ACK codebook may be a codebook for one-time HARQ-ACK feedback. The retransmission indicator may be included in an uplink grant that schedules multiple PUSCHs. The HARQ-ACK codebook may provide HARQ-ACK feedback for each of the plurality of HARQ processes, and the retransmission indicator may provide a retransmission indication for each of the plurality of HARQ processes.

The indicator may indicate: the HARQ-ACK feedback or retransmission indication for each of the plurality of HARQ processes is of TB level or CBG level. Process 1800 may proceed to S1899 and terminate at S1899.

Fig. 19 shows an example of a retransmission process 1900 according to an embodiment of the invention. In process 1900, HARQ retransmission information for TB level ACK/NACK combined with CBG level ACK/NACK for a negatively acknowledged HARQ process, or TB level new transmission or retransmission indication combined with CBG level retransmission indication for a HARQ process performing retransmission is sent from the receiver to the transmitter. Process 1900 may begin at S1901 and proceed to S1910.

At S1910, a TB including a CBG may be received at a receiver. The reception of the TB may be performed by the first HARQ process.

At S1920, HARQ retransmission information may be transmitted from the receiver. The HARQ retransmission information may be a HARQ-ACK codebook or retransmission indications for a number of HARQ processes configured at the receiver. For example, the HARQ-ACK codebook may be a codebook for one-time HARQ-ACK feedback. The retransmission indication may be included in an uplink grant that schedules multiple PUSCHs.

The HARQ retransmission information may include a first field and a second field. For the retransmission information being a HARQ-ACK codebook, the first field may indicate a TB level ACK or NACK for the first process. The second field of retransmission information may also indicate a CBG level ACK or NACK for the first HARQ process when a TB level NACK is indicated.

For the retransmission information being a retransmission indication, the first field may indicate a new transmission or retransmission of the first process. The second field of retransmission information may also provide a CBG level retransmission indication for the first HARQ process when retransmission is indicated. Process 1900 may proceed to S1999 and terminate at S1999.

Fig. 20 illustrates an example device 2000 in accordance with an embodiment of the present invention. The device 2000 may be configured to perform various functions in accordance with one or more embodiments or examples described herein. Thus, the device 2000 may provide means for implementing the mechanisms, techniques, processes, functions, components, systems described herein. For example, the apparatus 2000 may be used to implement the functions of the UE, BS, transmitter, and receiver in the various embodiments and examples described herein. The apparatus 2000 may include a general purpose processor or a specially designed circuit to implement the various functions, components or processes described herein in the various embodiments. The apparatus 2000 may include: processing circuitry 2010, memory 2020, and a Radio Frequency (RF) module 2030.

In various examples, processing circuitry 2010 may include circuitry configured to perform the functions and processes described herein, with or without software. In various examples, processing circuit 2010 may be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), a digital enhancement circuit, or the like, or a combination of these.

In certain other examples, the processing circuit 2010 may be a Central Processing Unit (CPU) configured to execute program instructions to perform various functions and processes described herein. Accordingly, the memory 2020 may be configured to store program instructions. Processing circuitry 2010 may perform the functions and processes described when executing the program instructions. The memory 2020 may also store other programs or data, such as an operating system, application programs, and the like. The memory 2020 may include: a non-transitory storage medium such as Read Only Memory (ROM), Random Access Memory (RAM), flash memory, solid state memory, a hard disk drive, an optical disk drive, and the like.

In an embodiment, the RF module 2030 receives the processed data signals from the processing circuitry 2010 and converts the processed data signals into beamformed wireless signals that are then transmitted via the antenna array 2040, or the RF module 2030 converts the beamformed signals received via the antenna array 2040 into data signals for processing by the processing circuitry 2010. The RF module 2030 may include a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), an up-converter (up converter), a down-converter (down converter), a filter, and an amplifier for receiving and transmitting operations. The RF module 2030 may include a multi-antenna circuit for a beamforming operation. For example, the multi-antenna circuit may include an uplink spatial filter circuit and a downlink spatial filter circuit for shifting the phase of the analog signal or scaling the amplitude of the analog signal. The antenna array 2040 may include one or more antenna arrays.

The apparatus 2000 may optionally include other components, such as input and output devices, additional or signal processing circuitry, and so forth. Thus, device 2000 is capable of performing other additional functions, such as executing applications, and handling alternative communication protocols.

The processes and functions described herein may be implemented as a computer program that, when executed by one or more processors, may cause the one or more processors to perform the respective processes and functions. The computer program may be stored or distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware. The computer program may also be distributed in other forms, such as being distributed via the internet or other wired or wireless telecommunication systems. The computer program may be obtained and loaded into the apparatus, for example, by means of a physical medium or by a distributed system, for example including from a server connected to the internet.

The computer program can be accessed from a computer-readable medium that provides program instructions for use by or in connection with a computer or any instruction execution system. The computer readable medium can include any apparatus that can store, communicate, propagate, or transport the computer program for use by or in connection with the instruction execution system, apparatus, or device. The computer readable medium can be a magnetic, optical, electronic, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. The computer-readable medium may include a computer-readable non-transitory storage medium such as a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a Random Access Memory (RAM), a read-only memory (ROM), a magnetic disk, an optical disk and the like. The computer-readable non-transitory storage medium may include all types of computer-readable media, including magnetic storage media, optical storage media, flash memory media, and solid state storage media.

While aspects of the present invention have been described in conjunction with specific embodiments thereof, which have been presented by way of example, alternatives, modifications, and variations may be made to these examples. Accordingly, the embodiments set forth herein are intended to be illustrative, not limiting. There are changes that may be made without departing from the scope of the claims as set forth.