WO2023077433A1

WO2023077433A1 - Method and apparatus for harq-ack codebook determination for multiple services

Info

Publication number: WO2023077433A1
Application number: PCT/CN2021/129020
Authority: WO
Inventors: Haipeng Lei
Original assignee: Lenovo (Beijing) Limited
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2023-05-11

Abstract

Embodiments of the present disclosure relate to HARQ-ACK codebook determination. According to some embodiments of the disclosure, a UE may receive a first set of DCI formats for scheduling a first set of PDSCHs, and a second set of DCI formats for scheduling a second set of PDSCHs. The UE may transmit a HARQ-ACK codebook comprising a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs. The HARQ-ACK codebook may be determined according to various methods as disclosed in the present disclosure.

Description

METHOD AND APPARATUS FOR HARQ-ACK CODEBOOK DETERMINATION FOR MULTIPLE SERVICES

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to wireless communication technology, and more particularly to hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook determination.

BACKGROUND

Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, broadcasts, and so on. Wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power) . Examples of wireless communication systems may include fourth generation (4G) systems, such as long term evolution (LTE) systems, LTE-advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may also be referred to as new radio (NR) systems.

In a wireless communication system, a user equipment (UE) may monitor a physical downlink control channel (PDCCH) in one or more search spaces. The PDCCH may carry downlink control information (DCI) , which may schedule uplink channels, such as a physical uplink shared channel (PUSCH) , or downlink channels, such as a physical downlink shared channel (PDSCH) . A UE may transmit hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback (e.g., included in a HARQ-ACK codebook) corresponding to PDSCH transmissions through a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) .

There is a need for handling HARQ-ACK codebook determination in a wireless communication system.

SUMMARY

Some embodiments of the present disclosure provide a user equipment (UE) . The UE may include: a transceiver; and a processor coupled to the transceiver. The processor may be configured to: receive a first set of downlink control information (DCI) formats for scheduling a first set of physical downlink shared channels (PDSCHs) , wherein the first set of PDSCHs is associated with a first service; receive a second set of DCI formats for scheduling a second set of PDSCHs, wherein the second set of PDSCHs is associated with a second service; and transmit a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook comprising a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs, wherein the first HARQ-ACK sub-codebook is placed in front of the second HARQ-ACK sub-codebook in the HARQ-ACK codebook.

In some examples, the second service may be a multicast service, and the second set of DCI formats may be group-common DCI formats and the second set of PDSCHs may be group-common PDSCHs.

In some examples, the first set of DCI formats may be UE-specific DCI formats and the first set of PDSCHs may be UE-specific PDSCHs in response to the first service being a unicast service; and the first set of DCI formats may be group-common DCI formats and the first set of PDSCHs may be group-common PDSCHs in response to the first service being a multicast service.

Some embodiments of the present disclosure provide a base station (BS) . The BS may include: a transceiver; and a processor coupled to the transceiver. The processor may be configured to: transmit, to a UE of a group of UEs, a first set of downlink control information (DCI) formats for scheduling a first set of physical downlink shared channels (PDSCHs) , wherein the first set of PDSCHs is associated with a first service; transmit, to the group of UEs, a second set of DCI formats for scheduling a second set of PDSCHs, wherein the second set of PDSCHs is associated with a second service; and receive, from the UE of the group UEs, a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook comprising a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs, wherein the first HARQ-ACK sub-codebook is placed in front of the second HARQ-ACK sub-codebook in the HARQ-ACK codebook.

Some embodiments of the present disclosure provide a method for wireless communication performed by a user equipment (UE) . The method may include: receiving a first set of downlink control information (DCI) formats for scheduling a first set of physical downlink shared channels (PDSCHs) , wherein the first set of PDSCHs is associated with a first service; receiving a second set of DCI formats for scheduling a second set of PDSCHs, wherein the second set of PDSCHs is associated with a second service; and transmitting a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook comprising a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs, wherein the first HARQ-ACK sub-codebook is placed in front of the second HARQ-ACK sub-codebook in the HARQ-ACK codebook.

Some embodiments of the present disclosure provide a method for wireless communication performed by a base station (BS) . The method may include: transmitting, to a UE of a group of UEs, a first set of downlink control information (DCI) formats for scheduling a first set of physical downlink shared channels (PDSCHs) , wherein the first set of PDSCHs is associated with a first service; transmitting, to the group of UEs, a second set of DCI formats for scheduling a second set of PDSCHs, wherein the second set of PDSCHs is associated with a second service; and receiving, from the UE of the group UEs, a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook comprising a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs, wherein the first HARQ-ACK sub-codebook is placed in front of the second HARQ-ACK sub-codebook in the HARQ-ACK codebook.

Some embodiments of the present disclosure provide an apparatus. According to some embodiments of the present disclosure, the apparatus may include: at least one non-transitory computer-readable medium having stored thereon computer-executable instructions; at least one receiving circuitry; at least one transmitting circuitry; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry, wherein the at least one non-transitory computer-readable medium and the computer executable instructions may be configured to, with the at least one processor, cause the apparatus to perform a method according to some embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the advantages and features of the disclosure can be obtained, a description of the disclosure is rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. These drawings depict only exemplary embodiments of the disclosure and are not therefore to be considered limiting of its scope.

FIG. 1 illustrates a schematic diagram of a wireless communication system in accordance with some embodiments of the present disclosure;

FIG. 2 illustrates a schematic diagram of HARQ-ACK codebook determination in accordance with some embodiments of the present disclosure;

FIG. 3 illustrates a schematic diagram of HARQ-ACK codebook determination in accordance with some embodiments of the present disclosure;

FIG. 4 illustrates an exemplary HARQ-ACK codebook in accordance with some embodiments of the present disclosure;

FIG. 5 illustrates an exemplary HARQ-ACK codebook in accordance with some embodiments of the present disclosure;

FIG. 6 illustrates a flow chart of an exemplary procedure of wireless communications in accordance with some embodiments of the present disclosure;

FIG. 7 illustrates a flow chart of an exemplary procedure of wireless communications in accordance with some embodiments of the present disclosure; and

FIG. 8 illustrates a block diagram of an exemplary apparatus in accordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the preferred embodiments of the present disclosure and is not intended to represent the only form in which the present disclosure may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present disclosure.

Reference will now be made in detail to some embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as the 3rd generation partnership project (3GPP) 5G (NR) , 3GPP long-term evolution (LTE) Release 8, and so on. It is contemplated that along with the developments of network architectures and new service scenarios, all embodiments in the present disclosure are also applicable to similar technical problems; and moreover, the terminologies recited in the present disclosure may change, which should not affect the principles of the present disclosure.

FIG. 1 illustrates a schematic diagram of a wireless communication system 100 in accordance with some embodiments of the present disclosure.

As shown in FIG. 1, a wireless communication system 100 may include some UEs 101 (e.g., UE 101a and UE 101b) and a base station (e.g., BS 102) . Although a specific number of UEs 101 and BS 102 are depicted in FIG. 1, it is contemplated that any number of UEs and BSs may be included in the wireless communication system 100.

The UE (s) 101 may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , or the like. According to some embodiments of the present disclosure, the UE (s) 101 may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network. In some embodiments of the present disclosure, the UE (s) 101 includes wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the UE (s) 101 may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art. The UE (s) 101 may communicate with the BS 102 via uplink (UL) communication signals.

The BS 102 may be distributed over a geographic region. In certain embodiments of the present disclosure, the BS 102 may also be referred to as an access point, an access terminal, a base, a base unit, a macro cell, a Node-B, an evolved Node B (eNB) , a gNB, a Home Node-B, a relay node, or a device, or described using other terminology used in the art. The BS 102 is generally a part of a radio access network that may include one or more controllers communicably coupled to one or more corresponding BSs 102. The BS 102 may communicate with UE (s) 101 via downlink (DL) communication signals.

The wireless communication system 100 may be compatible with any type of network that is capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with a wireless communication network, a cellular telephone network, a time division multiple access (TDMA) -based network, a code division multiple access (CDMA) -based network, an orthogonal frequency division multiple access (OFDMA) -based network, an LTE network, a 3GPP-based network, a 3GPP 5G network, a satellite communications network, a high altitude platform network, and/or other communications networks.

In some embodiments of the present disclosure, the wireless communication system 100 is compatible with 5G NR of the 3GPP protocol. For example, BS 102 may transmit data using an orthogonal frequency division multiple (OFDM) modulation scheme on the DL and the UE (s) 101 may transmit data on the UL using a discrete Fourier transform-spread-orthogonal frequency division multiplexing (DFT-S-OFDM) or cyclic prefix-OFDM (CP-OFDM) scheme. More generally, however, the wireless communication system 100 may implement some other open or proprietary communication protocols, for example, WiMAX, among other protocols.

In some embodiments of the present disclosure, the BS 102 and UE (s) 101 may communicate using other communication protocols, such as the IEEE 802.11 family of wireless communication protocols. Further, in some embodiments of the present disclosure, the BS 102 and UE (s) 101 may communicate over licensed spectrums, whereas in some other embodiments, the BS 102 and UE (s) 101 may communicate over unlicensed spectrums. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

In some embodiments of the present disclosure, the wireless communication system 100 may support multicast and broadcast services (MBSs) . For example, one or more UEs (e.g., UE 101a and UE 101b) may be grouped as an MBS group to receive a MBS (s) (e.g., an MBS PDSCH) from a BS (e.g., BS 102) .

A group-common radio network temporary identifier (RNTI) (e.g., group-RNTI (G-RNTI) ) is introduced for an MBS so that a UE can differentiate a DCI scheduling a group-common PDSCH carrying an MBS service (e.g., an MBS PDSCH) from a DCI scheduling UE-specific PDSCH carrying a unicast service. For example, the cyclic redundancy check (CRC) of the DCI scheduling the unicast PDSCH may be scrambled by a UE-specific RNTI (e.g., cell-RNTI (C-RNTI) ) and the scheduled unicast PDSCH may also be scrambled by the UE-specific RNTI. The CRC of the DCI scheduling the group-common PDSCH may be scrambled by a G-RNTI and the scheduled group-common PDSCH carrying the MBS may also be scrambled by the G-RNTI. When a UE supports multiple MBS services, each service may be configured with a G-RNTI specific to the service. In other words, from a UE’s perspective, the G-RNTIs can be used to differentiate the multiple MBS services.

The HARQ-ACK feedback from UEs corresponding to a downlink multicast transmission is essential for the multicast services in order to satisfy the QoS requirement, e.g., reliability. Two types of HARQ-ACK codebooks may be defined for HARQ-ACK multiplexing for multiple received PDSCHs. One may be named a Type-1 HARQ-ACK codebook (also referred to as “semi-static HARQ-ACK codebook” ) , and another may be named a Type-2 HARQ-ACK codebook (also referred to as “dynamic HARQ-ACK codebook” ) . The definitions of the Type-1 HARQ-ACK codebook and Type-2 HARQ-ACK codebook are specified in 3GPP specifications.

In some embodiments of the present disclosure, when UE is configured with parameters such as the pdsch-HARQ-ACK-Codebook, pdsch-HARQ-ACK-CodebookList, etc. for ACK/NACK-based feedback for multicast, the parameters may be applied to all G-RNTIs (all multicast services) configured to UE.

In some embodiments of the present disclosure, HARQ-ACK feedback for unicast and HARQ-ACK feedback for a multicast service (s) may be multiplexed in the same PUCCH resource. In some embodiments of the present disclosure, HARQ-ACK feedback for a plurality of multicast services may be multiplexed in the same PUCCH resource. In the above embodiments, separate Type-2 HARQ-ACK sub-codebooks may be generated for the unicast and multicast services, and then concatenated into a Type-2 HARQ-ACK codebook.

In some embodiments, for Type-2 HARQ-ACK codebook concatenation to be multiplexed in the same PUCCH resource, the Type-2 HARQ-ACK sub-codebook for unicast may precede the Type-2 HARQ-ACK sub-codebook (s) for the multicast service (s) . When a UE supports and is configured with a plurality of G-RNTIs (e.g., for a plurality of multicast services) , for Type-2 HARQ-ACK codebook construction, the downlink assignment indicator (DAI) may be separately counted per G-RNTI. Type-2 HARQ-ACK codebook may be constructed by concatenating the Type-2 HARQ-ACK sub-codebooks for the plurality of multicast services according to a predefined order (e.g., an ascending order of the corresponding G-RNTI values) .

For example, assuming a UE supports two MBS services, when HARQ-ACK feedback for the two MBS services is to be transmitted in the same slot and the two MBS services are of the same priority, the UE may multiplex the HARQ-ACK information bits for the two MBS services into one codebook, and then transmit it in a PUCCH. For instance, firstly, separate sub-codebooks may be generated for the two MBS services, where each sub-codebook includes HARQ-ACK information bits only for the corresponding MBS service arranged based on the order of the DAIs corresponding to each sub-codebook. Then, the two sub-codebooks may be concatenated in the ascending order of the G-RNTI values associated with the two MBS services. The concatenated sub-codebooks may be regarded as the final HARQ-ACK codebook and transmitted in the PUCCH in the indicated slot.

As mentioned above, the placement for the HARQ-ACK sub-codebooks for the multiple MBS services may be based on the ascending order of G-RNTI values. Assuming that a UE supports two MBS services, e.g., multicast 1 and multicast 2, and the G-RNTI value of multicast 1 is smaller than that of multicast 2, the HARQ-ACK sub-codebook for multicast 1 may be placed in front of the HARQ-ACK sub-codebook for multicast 2 in the HARQ-ACK codebook. Such construction method may cause a wrong HARQ-ACK codebook when the last DCI scheduling PDSCH for multicast 1 is missed by the UE. When the UE supports more than two MBS services, similar error case may happen.

For example, referring to FIG. 2, a BS may transmit, to a UE, four DCI formats 211-214 with DAIs equal to 1, 2, 3, and 4, respectively, to schedule four PDSCHs (e.g., PDSCHs #1-#4) associated with multicast service #1, and two

DCI formats

215 and 216 with DAIs equal to 1 and 2, respectively, to schedule two PDSCHs (e.g., PDSCHs #5 and #6) associated with multicast service #2.

Assuming that HARQ-ACK feedback for the six PDSCHs is to be transmitted in the same slot in PUCCH 231, HARQ-ACK feedback for the six PDSCHs will be multiplexed in the same HARQ-ACK codebook. The HARQ-ACK codebook may include two sub-codebooks, sub-codebook #1 includes HARQ-ACK information bits for PDSCHs #1-#4 associated with multicast service #1, and sub-codebook #2 includes HARQ-ACK information bits for PDSCHs #5 and #6 associated with multicast service #2. Sub-codebook #1 may be placed in front of sub-codebook #2 in the HARQ-ACK codebook. When there is no DCI format missed by the UE, the UE may transmit a HARQ-ACK codebook, for example, { {a0, a1, a2, a3} , {b0, b1} } , to the BS, where {a0, a1, a2, a3} are sub-codebook #1 including HARQ-ACK information bits for PDSCHs #1-#4, and {b0, b1} are sub-codebook #2 including HARQ-ACK information bits for PDSCHs #5 and #6. However, when DCI format 214 scheduling PDSCH #4 for multicast service #1 is missed by the UE, which cannot be identified by the UE since it is the last DCI format for PDSCHs for multicast service #1, the UE may transmit a wrong HARQ-ACK codebook, for example, { {a0, a1, a2} , {b0, b1} } , to the BS. Since the HARQ-ACK information bit (s) (e.g., a3) for PDSCH #4 is not included in the final HARQ-ACK codebook, the BS may misunderstand b0 as the HARQ-ACK feedback for PDSCH #4 and regard b1 as the HARQ-ACK feedback for PDSCH #5. Therefore, the HARQ-ACK information bits may be shifted at least one bit forward. Such misunderstanding between the UE and the BS may cause the retransmission of unnecessary PDSCHs by the BS, and thus degrade the DL performance.

Furthermore, when the HARQ-ACK feedback for PDSCHs carrying a unicast service is to be transmitted in the same slot with the HARQ-ACK feedback for PDSCHs carrying one or more MBS services, and the unicast service and the one or more MBS services are of the same priority, the UE will multiplex the HARQ-ACK information bits for the unicast service and the one or more MBS services into one HARQ-ACK codebook. The HARQ-ACK codebook may include multiple sub-codebooks, i.e., a first sub-codebook includes HARQ-ACK information bits for the unicast service, a second sub-codebook includes HARQ-ACK information bits for an MBS service with the lowest G-RNTI value among the one or more MBS services, a third sub-codebook includes HARQ-ACK information bits for another MBS service with the second lowest G-RNTI value among the one or more MBS services, till the last sub-codebook includes HARQ-ACK information bits for the last MBS service with the highest G-RNTI value among the one or more MBS services. Similar HARQ-ACK misunderstanding as described above may happen. In addition, when the UE supports one MBS service or more than two MBS services with HARQ-ACK feedback to be transmitted with the unicast service, similar error case may happen.

For example, referring to FIG. 3, a BS may transmit, to a UE, four DCI formats 311-314 with DAIs equal to 1, 2, 3, and 4, respectively, to schedule four PDSCHs (e.g., PDSCHs #1’-#4’) associated with the unicast service, two

DCI formats

315 and 316 with DAIs equal to 1 and 2, respectively, to schedule two PDSCHs (e.g., PDSCHs #5’ and #6’) associated with multicast service #1’, and two

DCI formats

317 and 318 with DAIs equal to 1, 2, respectively, to schedule two PDSCHs (e.g., PDSCHs #7’ and #8’) associated with multicast service #2’. Assuming that HARQ-ACK feedback for the eight PDSCHs is to be transmitted in the same slot in PUCCH 331, HARQ-ACK feedback for the eight PDSCHs will be multiplexed in the same HARQ-ACK codebook. When DCI format 314 scheduling PDSCH #4’ for the unicast service, or DCI format 316 scheduling PDSCH #6’ for multicast service #1’ is missed by the UE, which cannot be identified by the UE since DCI format 314 is the last DCI format for PDSCHs for the unicast service and DCI format 316 is the last DCI format for PDSCHs for multicast service #1’, the UE may transmit a wrong HARQ-ACK codebook to the BS.

Embodiments of the present disclosure provide solutions for HARQ-ACK codebook determination. For example, solutions for determining a HARQ-ACK codebook when multiple MBS services are supported are proposed. For example, solutions for determining a HARQ-ACK codebook when HARQ-ACK feedback for at least one MBS service and a unicast service is to be transmitted in the same slot are proposed. These solutions can solve the HARQ-ACK codebook misunderstanding between a UE and a BS. More details on the embodiments of the present disclosure will be illustrated in the following text in combination with the appended drawings.

In some embodiments of the present disclosure, for a UE supporting a plurality of MBS services, RRC signaling may be used to configure a plurality of G-RNTI values with each G-RNTI corresponding to a respective multicast service and a plurality of priority values with each priority value corresponding to a respective multicast service. In response to the reception of the RRC signaling, the UE can determine the maximum number of HARQ-ACK sub-codebooks for multicast services with each sub-codebook corresponding to a respective multicast service based on the maximum number of multicast services with the same priority. For example, the UE can derive the maximum number of HARQ-ACK sub-codebooks for multicast services with priority 0 and the maximum number of HARQ-ACK sub-codebooks for multicast services with priority 1. Since, in some embodiments, multicast services with different priority values may be not supported to be multiplexed in the same HARQ-ACK codebook, based on the derived maximum number of HARQ-ACK sub-codebooks for multicast services with

priority

0 or 1, the UE can generate the HARQ-ACK codebook according to the maximum number of HARQ-ACK sub-codebooks for

priority

0 or 1.

In some embodiments of the present disclosure, for a UE supporting a plurality of multicast services, the final HARQ-ACK codebook may include a plurality of HARQ-ACK sub-codebooks for the plurality of multicast services. For each multicast service, the HARQ-ACK information bits in the corresponding sub-codebook may be ordered based on the corresponding DAIs separately.

In some embodiments, the final HARQ-ACK codebook may also include a HARQ-ACK sub-codebook for the unicast service, which may be placed at a predefined position of the final HARQ-ACK codebook, for example, in front of all HARQ-ACK sub-codebooks for the multicast services in the HARQ-ACK codebook. Although the following embodiments may be described with respect to the HARQ-ACK sub-codebook for the multicast service, it is contemplated that all embodiments in the present disclosure are also applicable to the HARQ-ACK sub-codebook for the unicast service.

In some embodiments of the present disclosure, from the UE’s perspective, the last (or latest) received DAI among the DCIs scheduling PDSCHs carrying a specific multicast service with corresponding HARQ-ACK information bits in the same sub-codebook may be included in a predefined position in the HARQ-ACK codebook. For example, the predefined position may be the beginning of the HARQ-ACK codebook or the end of the HARQ-ACK codebook. In some examples, when the final HARQ-ACK codebook size is smaller than a specific value (e.g., 11) , padding bit (s) (e.g., NACK bit (s) ) may be appended to the HARQ-ACK codebook for Reed-Muller (RM) coding. For example, (32, K) RM coding may be used to encode the final HARQ-ACK codebook, where 11 basic sequences are defined to support encoding of maximum 11 HARQ-ACK information bits.

In this way, the BS can determine whether the last (or latest) transmitted DCI among the DCIs scheduling PDSCHs carrying a specific multicast service with corresponding HARQ-ACK information bits in the same sub-codebook is missed by the UE by comparing whether the DAI in the HARQ-ACK codebook is equal to or smaller than the DAI in the last transmitted DCI (hereinafter, “last transmitted DAI” ) . For example, when the DAI in the HARQ-ACK codebook is equal to the last transmitted DAI, the BS may determine that the last transmitted DCI for the multicast service is not missed by the UE. Otherwise, when the DAI in the HARQ-ACK codebook is smaller than the last transmitted DAI, the BS may determine that the last transmitted DCI for the multicast service is missed, and may adjust the received HARQ-ACK codebook. For example, in response to determine the last transmitted DCI is missed, the BS may insert padding bit (s) (e.g., NACK bit (s) ) in the HARQ-ACK codebook for the PDSCH scheduled by the missed DCI, and identify the HARQ-ACK information bits of the immediately following sub-codebook. In this way, even when the last transmitted DCI is missed by a UE, in response to the reception of the last received DAI of the UE, the BS can adjust the bit positions of the multiple sub-codebooks so as to obtain a correct understanding on the HARQ-ACK codebook.

In some embodiments, all last received DAIs for the multicast services with HARQ-ACK feedback to be transmitted in the same HARQ-ACK codebook except the one for the multicast service with a sub-codebook arranged at the end of the HARQ-ACK codebook (e.g., the multicast service associated with the largest G-RNTI value) are included in the HARQ-ACK codebook. In some embodiments, all last received DAIs for the multicast services with HARQ-ACK feedback to be transmitted in the same HARQ-ACK codebook are included in the HARQ-ACK codebook. In some embodiments, the last received DAIs in the HARQ-ACK codebook may be arranged according to a predefined order in the HARQ-ACK codebook. For example, the last received DAIs in the HARQ-ACK codebook may be arranged in the same order as the HARQ-ACK sub-codebooks.

For example, it is assumed that DAI “00” , “01” , “10” , and “11” indicate values of 1, 2, 3, 4, respectively, and for simplicity it is further assumed that each PDSCH corresponds to a single HARQ-ACK information bit. Referring back to FIG. 2, when DCI format 214 for multicast service #1 is not missed, the last received DAI for multicast service #1 is “11” indicating value of 4 from the UE’s perspective. The UE may generate HARQ-ACK codebook 400 as shown in FIG. 4. As shown in FIG. 4, HARQ-ACK codebook 400 may include a field 411, which indicates the last received DAI (e.g., “11” ) for multicast service #1, at the beginning of the HARQ-ACK codebook, followed by

fields

412 and 413, which may respectively correspond to HARQ-ACK sub-codebooks for multicast services #1 and #2. The HARQ-ACK sub-codebook for multicast service #1 may include HARQ-ACK information bits {a0, a1, a2, a3} for PDSCHs #1-#4, respectively. The HARQ-ACK sub-codebook for multicast service #2 may include HARQ-ACK information bits {b0, b1} for PDSCHs #5 and #6, respectively. Hence, the UE may generate a HARQ-ACK codebook of {1, 1, a0, a1, a2, a3, b0, b1} . Since the size of the HARQ-ACK codebook is smaller than 11 bits, the UE may add padding bits to the HARQ-ACK codebook (e.g., at a predefined position) until the size of the HARQ-ACK codebook after padding is 11 bits. For example, three NACK bits may be added to the end of HARQ-ACK codebook 400 (e.g., field 414) .

Referring back to FIG. 2, when DCI format 214 for multicast service #1 is missed by the UE and DCI format 213 is received by the UE, the last received DAI for multicast service #1 is “10” indicating value of 3 from the UE’s perspective. The UE may generate HARQ-ACK codebook 500 as shown in FIG. 5. As shown in FIG. 5, HARQ-ACK codebook 500 may include a field 511, which indicates the last received DAI (e.g., “10” ) for multicast service #1, at the beginning of the HARQ-ACK codebook, followed by

fields

512 and 513, which may respectively correspond to HARQ-ACK sub-codebooks for multicast services #1 and #2. The HARQ-ACK sub-codebook for multicast service #1 may include HARQ-ACK information bits {a0, a1, a2} for PDSCHs #1-#3, respectively. The HARQ-ACK sub-codebook for multicast service #2 may include HARQ-ACK information bits {b0, b1} for PDSCHs #5 and #6, respectively. Hence, the UE may generate a HARQ-ACK codebook of {1, 1, a0, a1, a2, b0, b1} . Since the size of the HARQ-ACK codebook is smaller than 11 bits, the UE may add padding bits to the HARQ-ACK codebook (e.g., at a predefined position) until the size of the HARQ-ACK codebook after padding is 11 bits. For example, four NACK bits may be added to the end of HARQ-ACK codebook 500 (e.g., field 514) .

At the BS side, since the last transmitted DAI for multicast service #1 is 4, in response to the reception of the HARQ-ACK codebook, when the value of the DAI in the HARQ-ACK codebook equals to 4, the BS may determine that the last transmitted DCI for multicast service #1 is not missed by the UE and the bit positions of the received HARQ-ACK codebook are correct. Otherwise, when the value of the DAI for multicast service #1 in the HARQ-ACK codebook is smaller than 4, for example, equals to 3 as shown in FIG. 5, the BS may determine that the last transmitted DCI for multicast service #1 is missed by the UE and may insert a padding bit (e.g., NACK bit) for the PDSCH scheduled by the missed DCI. For example, referring to FIG. 5, the BS may add a NACK bit between a2 and b0. After the insertion of the NACK bit, the bit positions of the HARQ-ACK codebook are correct. In this way, when the last transmitted DCI is missed, there is no misunderstanding between the BS and UE on the HARQ-ACK codebook.

In some embodiments of the present disclosure, to avoid any ambiguity between the BS and the UE on the HARQ-ACK sub-codebook size, HARQ-ACK feedback quantification may be employed to align the size of a HARQ-ACK sub-codebook for a corresponding multicast service to a value in a set of potential values. The set of potential values for HARQ-ACK sub-codebook size for a multicast service may be configured by RRC signaling or predefined in a standard (s) . Examples of the set of potential values may include {2, 4, 6, 8, 10, 12, etc. } and {4, 8, 12, etc. } .

In some examples, different multicast services may share the same set of potential values for HARQ-ACK sub-codebook size. In some examples, different multicast services may be configured with respective sets of potential values for HARQ-ACK sub-codebook size. For example, two different multicast services may be associated with different sets of potential values.

In some examples, HARQ-ACK feedback quantification may not be applied to the HARQ-ACK sub-codebook arranged at the end of the HARQ-ACK codebook. In some examples, HARQ-ACK feedback quantification may be applied to all HARQ-ACK sub-codebooks in the HARQ-ACK codebook.

The BS may take the potential values into consideration when perform DL scheduling. For example, when a multicast service is associated with a set of HARQ-ACK sub-codebook sizes {4, 8, 12, etc. } , the BS may not schedule 5 DCIs which schedules PDSCHs for the multicast service with HARQ-ACK feedback to be transmitted in the same slot, since the UE may generate a HARQ-ACK sub-codebook size of 4 even when the last transmitted DCI for the multicast service is missed by the UE.

Assuming that a multicast service is associated with a set of HARQ-ACK sub-codebook sizes {2, 4, 6, 8, 10, 12, etc. } , when a UE determines that the HARQ-ACK sub-codebook size for the multicast service is 3 based on the received PDSCH transmissions for the multicast service. The UE may update the HARQ-ACK sub-codebook size to 4 by looking up the set of potential values. For example, the UE may select a minimum value (e.g., 4) which is equal to or greater than the determined size of 3 from the set of potential values as the final HARQ-ACK sub-codebook size for the multicast service. Since 4 is greater than 3, the UE may add one padding bit (e.g., a NACK bit) to the HARQ-ACK sub-codebook for the multicast service such that the size of the final HARQ-ACK sub-codebook is equal to 4. The padding bit may be added to the predefined position (e.g., at the end) of the HARQ-ACK sub-codebook. When the HARQ-ACK sub-codebook size based on the received PDSCH transmissions for the multicast service is equal to a value in the set of HARQ-ACK sub-codebook sizes, no padding is needed. In other words, the final HARQ-ACK sub-codebook size should be a value in the set of potential values; otherwise, padding may be performed to make the final HARQ-ACK sub-codebook size equal to a next nearest value in the set of potential values.

The BS and the UE may maintain the same set (s) of potential values of HARQ-ACK sub-codebook size for the multicast service (s) . In this way, no ambiguity on the HARQ-ACK sub-codebook size for a multicast service would occur.

After HARQ-ACK feedback quantification for each HARQ-ACK sub-codebook, the final HARQ-ACK codebook may be generated by concatenating the quantified sub-codebooks in a predefined order as described above, for example, according to the ascending order to the G-RNTI values associated with the multicast services. At the BS side, the BS may firstly determine the size of each HARQ-ACK sub-codebook by quantification and then determine the size of the whole HARQ-ACK codebook.

For example, it is assumed that a set of potential values for HARQ-ACK sub-codebook size, {2, 4, 6, 8} , is configured by RRC signaling for a plurality of multicast services. For simplicity, it is assumed that a single HARQ-ACK information bit is required for each PDSCH. Referring back to FIG. 2, when DCI format 214 for multicast service #1 and DCI format 216 for multicast service #2 is not missed, the UE may generate a HARQ-ACK sub-codebook {a0, a1, a2, a3} for multicast service #1, which is well aligned with the potential sub-codebook size of 4 so that no padding is needed, and a HARQ-ACK sub-codebook {b0, b1} for multicast service #2, which is well aligned with the potential sub-codebook size of 2 so that no padding is needed. Hence, the UE may transmit the HARQ-ACK codebook, {a0, a1, a2, a3, b0, b1} , to the BS in PUCCH 231.

However, when DCI format 214 for multicast service #1 is missed by the UE, since the UE may only receive three PDSCHs, PDSCHs #1-#3, the UE may only generate 3 bits in the sub-codebook, e.g., {a0, a1, a2} , for multicast service #1 for the three PDSCHs. For a sub-codebook size of 3, the next nearest value in the set of potential values for HARQ-ACK sub-codebook size is 4. Therefore, the UE may add a padding bit (e.g., NACK) to the sub-codebook for multicast service #1 to guarantee that the sub-codebook size is equal to 4. For example, the final sub-codebook for multicast service #1 may be {a0, a1, a2, NACK} .

When DCI format 216 for multicast service #2 is not missed by the UE, the UE may generate a HARQ-ACK sub-codebook {b0, b1} for multicast service #2, which is well aligned with the potential sub-codebook size of 2 so that no padding is needed. Hence, the UE may transmit the HARQ-ACK codebook, {a0, a1, a2, NACK, b0, b1} , to the BS in PUCCH 231.

In some examples, when DCI format 216 for multicast service #2 is missed by the UE, the UE may generate a HARQ-ACK sub-codebook {b0, NACK} for multicast service #2 based on the HARQ-ACK feedback quantification. Hence, the UE may transmit the HARQ-ACK codebook, {a0, a1, a2, NACK, b0, NACK} , to the BS in PUCCH 231. In some other examples, HARQ-ACK feedback quantification may not be applied to the last HARQ-ACK sub-codebook in the HARQ-ACK codebook. Hence, the UE may transmit the HARQ-ACK codebook, {a0, a1, a2, NACK, b0} , to the BS in PUCCH 231.

In this way, the HARQ-ACK information bit (s) for a PDSCH (s) scheduled by a missed DCI format is not shifted and the same HARQ-ACK codebook size can be guaranteed between both the BS and UE. On the other hand, when the BS only transmits three DCIs for scheduling three PDSCHs for multicast service #1, all of which are received by the UE, the UE may still add a padding bit (e.g., a NACK bit) to the sub-codebook for multicast service #1 such that the sub-codebook size for multicast service #1 is equal to the next nearest value (e.g., 4) in the set of potential values for HARQ-ACK sub-codebook size.

In some embodiments of the present disclosure, for the UE supporting a plurality of multicast services, the final HARQ-ACK codebook may include a plurality of HARQ-ACK sub-codebooks for the plurality of multicast services. The sub-codebook size for a multicast service of the plurality of multicast services may be configured by RRC signaling. For example, the sub-codebook size may be configured as 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. The UE may not be expected to receive PDSCHs carrying a multicast service with the number of corresponding HARQ-ACK information bits to be transmitted in the same slot larger than the RRC configured sub-codebook size.

In this way, even when the last transmitted DCI of a multicast service is missed, the bit positions of the plurality of sub-codebooks for the plurality of multicast services will not be impacted.

In some examples, different multicast services may share the same RRC configured sub-codebook size. In some examples, different multicast services may be configured with respective RRC configured sub-codebook sizes. For example, two different multicast services may be configured with different sub-codebook sizes.

In some examples, the RRC configured sub-codebook size for multicast may be applied all the sub-codebooks for the multicast services to be multiplexed to the same HARQ-ACK codebook except the last multicast sub-codebook in the HARQ-ACK codebook (e.g., the multicast sub-codebook corresponding to the multicast service with the largest G-RNTI value of the supported multiple multicast services) since the bit positions of the HARQ-ACK codebook would not be impacted when the last transmitted DCI for the corresponding multicast service (e.g., the one with the largest G-RNTI value) is missed. In some examples, the RRC configured sub-codebook size for multicast can be applied all the sub-codebooks for the multicast services to be multiplexed to the same HARQ-ACK codebook.

For example, it is assumed that the sub-codebook size for multicast is configured as 4 and applied to all sub-codebooks for the multicast services except the last one in the HARQ-ACK codebook. For simplicity, it is assumed that a single HARQ-ACK information bit is required for each PDSCH. Referring back to FIG. 2, when DCI format 214 for multicast service #1 and DCI format 216 for multicast service #2 is not missed, the UE may generate a HARQ-ACK sub-codebook {a0, a1, a2, a3} for multicast service #1 and a HARQ-ACK sub-codebook {b0, b1} for multicast service #2. Hence, the UE may transmit a HARQ-ACK codebook, {a0, a1, a2, a3, b0, b1} , to the BS in PUCCH 231.

When DCI format 214 for multicast service #1 is missed by the UE, this error case cannot be identified by the UE since DCI format 214 is the last DCI format for PDSCHs for multicast service #1. According to the configured sub-codebook size for multicast, the UE may add a padding bit (e.g., a NACK bit) to the sub-codebook for multicast service #1 to guarantee that the sub-codebook size is equal to the configured size of 4. That is, the UE may generate a sub-codebook of {a0, a1, a2, NACK} for multicast service #1 corresponding to PDSCHs #1-#4. The UE may transmit a HARQ-ACK codebook, for example, {a0, a1, a2, NACK, b0, b1} , to the BS.

In this way, the HARQ-ACK information bit (s) for a PDSCH (s) scheduled by a missed DCI format is not shifted and the same HARQ-ACK codebook size can be guaranteed between both the BS and UE. On the other hand, when the BS only transmits three DCIs for scheduling three PDSCHs for multicast service #1, the UE may add a padding bit (s) to the sub-codebook for multicast service #1 such that the sub-codebook size for multicast service #1 is equal to the RRC configured size of 4.

In another example, when it is assumed that the sub-codebook size for multicast is applied to all sub-codebooks for the multicast services, the UE may transmit a HARQ-ACK codebook, for example, {a0, a1, a2, NACK, b0, b1, NACK, NACK} , to the BS, wherein the last two NACK bits are padding bits for the sub-codebook for multicast service #2 (so that the sub-codebook size is 4) .

In some embodiments of the present disclosure, to avoid any ambiguity between the BS and the UE on the HARQ-ACK sub-codebook size, different PUCCH resources may be indicated (e.g., by a PUCCH resource indicator (PRI) ) in the last transmitted DCI format and the penultimately transmitted DCI format for a multicast service (hereinafter, “multicast service #1A” ) , the sub-codebook of which is placed prior to that of another multicast service (hereinafter, “multicast service #2A” ) in a HARQ-ACK codebook. For example, the G-RNTI value associated with multicast service #1A is smaller than the one associated with multicast service #2A.

At the BS side, when the PUCCH carrying the HARQ-ACK codebook for the two multicast services is detected in the PUCCH resource indicated in the last transmitted DCI for multicast service #1A, the BS may determine that the last transmitted DCI for multicast service #1A is not missed by the UE and the bit positions in the HARQ-ACK codebook are not shifted. When the PUCCH carrying the HARQ-ACK codebook for the two multicast services is detected in the PUCCH resource indicated in the penultimately transmitted DCI for multicast service #1A, the BS may determine that the last transmitted DCI for multicast service #1A is missed by the UE, and the bit positions in the HARQ-ACK codebook are shifted due to the missed DCI. In this case, the BS will adjust the received HARQ-ACK codebook. For example, the BS may insert a padding bit (s) (e.g., NACK bit (s) ) in the HARQ-ACK codebook for the PDSCH scheduled by the missed DCI for multicast service #1A, identify the HARQ-ACK information bits of the immediately following sub-codebook (e.g., the sub-codebook for multicast service #2A) . In this way, the BS can determine whether the HARQ-ACK information bits are shifted or not. Even when the last transmitted DCI is missed by a UE, in response to the detection of a PUCCH in the resource indicated in the penultimately transmitted DCI for multicast service #1A (which is the last received DCI for multicast service #1A from the perspective of the UE) , the BS can adjust the bit positions of the multiple sub-codebooks so as to obtain a correct understanding on the HARQ-ACK codebook. From the UE’s perspective, the UE may expect different PUCCH resources indicated by the last transmitted DCI and the penultimately transmitted DCI for multicast service #1A. The UE may transmit the HARQ-ACK codebook on the PUCCH resource indicated by the last received DCI for multicast service #1A.

Although the above methods for solving the HARQ-ACK codebook misunderstanding between a UE and a BS are described with respect to the HARQ-ACK sub-codebooks for multicast services, it is contemplated that the above methods can also be applied to the HARQ-ACK sub-codebook for a unicast service. For example, when the HARQ-ACK feedback for a unicast service and at least one MBS service is to be transmitted in the same slot, the above methods may be applied to the sub-codebook for the at least one MBS service, as well as the sub-codebook for the unicast service.

For instance, the last (or latest) received DAI among the DCIs scheduling PDSCHs carrying the unicast service may be included in the HARQ-ACK codebook at, for example, a predefined position. For example, the last received DAIs in the HARQ-ACK codebook may be arranged in the same order as the HARQ-ACK sub-codebooks. For example, the last received DAI corresponding to the unicast service may be placed in the front of all last received DAIs indicated in the HARQ-ACK codebook. For instance, HARQ-ACK feedback quantification may be applied to the HARQ-ACK sub-codebook for the unicast service. For instance, the size of the sub-codebook for the unicast service may be configured by RRC signaling. For instance, different PUCCH resources may be indicated in the last transmitted DCI format and the penultimately transmitted DCI format for the unicast service.

FIG. 6 illustrates a flow chart of an exemplary procedure 600 for wireless communications in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 6. In some examples, the procedure may be performed by a UE, for example, UE 101 in FIG. 1.

Referring to FIG. 6, in operation 611, a UE may receive a first set of DCI formats for scheduling a first set of PDSCHs. The first set of PDSCHs may be associated with a first service. In operation 613, the UE may receive a second set of DCI formats for scheduling a second set of PDSCHs. The second set of PDSCHs may be associated with a second service.

In some embodiments, the second service may be a multicast service, and the second set of DCI formats may be group-common DCI formats and the second set of PDSCHs may be group-common PDSCHs. In some embodiments, the first service may be a unicast service. In these embodiments, the first set of DCI formats may be UE-specific DCI formats and the first set of PDSCHs may be UE-specific PDSCHs. In some embodiments, the first service may be a multicast service. For example, the first and second services may be different multicast services. In these embodiments, the first set of DCI formats may be group-common DCI formats and the first set of PDSCHs may be group-common PDSCHs.

In operation 615, the UE may transmit a HARQ-ACK codebook including a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs. The first HARQ-ACK sub-codebook may be placed in front of the second HARQ-ACK sub-codebook in the HARQ-ACK codebook.

In some embodiments, the HARQ-ACK codebook may include a DAI indicated in a DCI format last received among the first set of DCI formats. The DAI may be placed in a predefined position in the HARQ-ACK codebook. The size of the first HARQ-ACK sub-codebook may be determined based on the value of the DAI indicated in the DCI format last received among the first set of DCI formats.

In some embodiments, the UE may determine a first sub-codebook size for the first HARQ-ACK sub-codebook based on a first set of HARQ-ACK sub-codebook sizes (e.g., a set of potential values for HARQ-ACK sub-codebook size as described above) . The first set of HARQ-ACK sub-codebook sizes may be configured by RRC signaling or predefined. In some examples, to determine the first sub-codebook size, the UE may determine a second HARQ-ACK sub-codebook size based on the first set of PDSCHs, and may select, from the first set of HARQ-ACK sub-codebook sizes, a minimum value which is equal to or greater than the second HARQ-ACK sub-codebook size as the first sub-codebook size. In some examples, the UE may add a padding bit (s) to the first HARQ-ACK sub-codebook until the size of the first HARQ-ACK sub-codebook is equal to the determined first sub-codebook size.

In some examples, the UE may determine a second sub-codebook size for the second HARQ-ACK sub-codebook based on a second set of HARQ-ACK sub-codebook sizes. The second set of HARQ-ACK sub-codebook sizes may be configured by RRC signaling or predefined. The second set of HARQ-ACK sub-codebook sizes may be different or the same as the first set of HARQ-ACK sub-codebook sizes.

In some embodiments, the size of the first HARQ-ACK sub-codebook may be equal to a first predetermined HARQ-ACK sub-codebook size. The first predetermined HARQ-ACK sub-codebook size may be configured by RRC signaling or predefined. In some examples, the UE may add a padding bit (s) to the first HARQ-ACK sub-codebook until the size of the first HARQ-ACK sub-codebook is equal to the first predetermined HARQ-ACK sub-codebook size.

In some examples, the size of the second HARQ-ACK sub-codebook may be equal to a second predetermined HARQ-ACK sub-codebook size. The second predetermined HARQ-ACK sub-codebook size may be configured by RRC signaling or predefined. The second predetermined HARQ-ACK sub-codebook size may be different or the same as the first predetermined HARQ-ACK sub-codebook size.

In some embodiments, the HARQ-ACK codebook may be transmitted in a first uplink resource indicated by a DCI format last received among the first set of DCI formats. In some examples, the first uplink resource may be different from a second uplink resource indicated by a DCI format penultimately received among the first set of DCI formats.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary procedure 600 may be changed and some of the operations in exemplary procedure 600 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 7 illustrates a flow chart of an exemplary procedure 700 for wireless communications in accordance with some embodiments of the present disclosure. Details described in all of the foregoing embodiments of the present disclosure are applicable for the embodiments shown in FIG. 7. In some examples, the procedure may be performed by a BS, for example, BS 102 in FIG. 1.

Referring to FIG. 7, in operation 711, a BS may transmit, to a UE of a group of UEs, a first set of DCI formats for scheduling a first set of PDSCHs. The first set of PDSCHs may be associated with a first service. In operation 713, the BS may transmit, to the group of UEs, a second set of DCI formats for scheduling a second set of PDSCHs. The second set of PDSCHs may be associated with a second service.

In operation 715, the BS may receive, from the UE, a HARQ-ACK codebook including a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs. The first HARQ-ACK sub-codebook may be placed in front of the second HARQ-ACK sub-codebook in the HARQ-ACK codebook.

In some embodiments, the HARQ-ACK codebook may include a DAI indicated in a DCI format last received by the UE among the first set of DCI formats. The DAI may be placed in a predefined position in the HARQ-ACK codebook, for example, at the beginning or at the end of the HARQ-ACK codebook. The size of the first HARQ-ACK sub-codebook may be based on the value of the DAI indicated in the DCI format last received by the UE among the first set of DCI formats.

The BS may determine whether the UE has missed a DCI format of the first set of DCI formats based on the DAI in the HARQ-ACK codebook. For example, in response to the DAI in the HARQ-ACK codebook is equal to the DAI indicated in the last transmitted DCI format of the first set of DCI formats, the BS may determine that the last transmitted DCI format is not missed by the UE. In response to the DAI in the HARQ-ACK codebook is smaller than the DAI indicated in the last transmitted DCI format of the first set of DCI formats, the BS may determine that the last transmitted DCI format is missed by the UE. In some examples, in response to determining that the UE has missed a DCI format of the first set of DCI formats (e.g., the last transmitted DCI format of the first set of DCI formats) , the BS may add a padding bit (s) to the first HARQ-ACK sub-codebook for the PDSCH scheduled by the missed DCI format.

In some embodiments, the BS may determine a first sub-codebook size for the first HARQ-ACK sub-codebook based on a first set of HARQ-ACK sub-codebook sizes (e.g., a set of potential values for HARQ-ACK sub-codebook size as described above) . In some examples, the BS may transmit, to the UE, RRC signaling to configure the first set of HARQ-ACK sub-codebook sizes. In some examples, the first set of HARQ-ACK sub-codebook sizes may be predefined.

In some examples, to determine the first sub-codebook size, the BS may determine a second HARQ-ACK sub-codebook size based on the first set of PDSCHs, and may select, from the first set of HARQ-ACK sub-codebook sizes, a minimum value which is equal to or greater than the second HARQ-ACK sub-codebook size as the first sub-codebook size.

In some examples, the BS may determine a second sub-codebook size for the second HARQ-ACK sub-codebook based on a second set of HARQ-ACK sub-codebook sizes. The second set of HARQ-ACK sub-codebook sizes may be configured to the UE by the BS via RRC signaling or predefined. The second set of HARQ-ACK sub-codebook sizes may be different or the same as the first set of HARQ-ACK sub-codebook sizes.

In some embodiments, the size of the first HARQ-ACK sub-codebook may be equal to a first predetermined HARQ-ACK sub-codebook size. In some examples, the BS may transmit, to the UE, RRC signaling to configure the first predetermined HARQ-ACK sub-codebook size. In some examples, the first predetermined HARQ-ACK sub-codebook size may be predefined. In some examples, the size of the second HARQ-ACK sub-codebook may be equal to a second predetermined HARQ-ACK sub-codebook size. The second predetermined HARQ-ACK sub-codebook size may be configured to the UE by the BS via RRC signaling or predefined. The second predetermined HARQ-ACK sub-codebook size may be different or the same as the first predetermined HARQ-ACK sub-codebook size.

In some embodiments, the last transmitted DCI format among the first set of DCI formats may indicate a first uplink resource which is different from a second uplink resource indicated by the penultimately transmitted DCI format among the first set of DCI formats. The BS may determine whether the UE has missed a DCI format of the first set of DCI formats based on the uplink resource on which the HARQ-ACK codebook is received.

For instance, in some examples, in response to receiving the HARQ-ACK codebook in the first uplink resource, the BS may determine that the UE has not missed the last transmitted DCI format. In some examples, in response to receiving the HARQ-ACK codebook in the second uplink resource, the BS may that the UE has missed the last transmitted DCI format. The BS may add a padding bit (s) to the first HARQ-ACK sub-codebook for the PDSCH scheduled by the missed DCI format.

It should be appreciated by persons skilled in the art that the sequence of the operations in exemplary procedure 700 may be changed and some of the operations in exemplary procedure 700 may be eliminated or modified, without departing from the spirit and scope of the disclosure.

FIG. 8 illustrates a block diagram of an exemplary apparatus 800 according to some embodiments of the present disclosure. As shown in FIG. 8, the apparatus 800 may include at least one processor 806 and at least one transceiver 802 coupled to the processor 806. The apparatus 800 may be a UE or a BS.

Although in this figure, elements such as the at least one transceiver 802 and processor 806 are described in the singular, the plural is contemplated unless a limitation to the singular is explicitly stated. In some embodiments of the present application, the transceiver 802 may be divided into two devices, such as a receiving circuitry and a transmitting circuitry. In some embodiments of the present application, the apparatus 800 may further include an input device, a memory, and/or other components.

In some embodiments of the present application, the apparatus 800 may be a UE. The transceiver 802 and the processor 806 may interact with each other so as to perform the operations with respect to the UE described in FIGS. 1-7. In some embodiments of the present application, the apparatus 800 may be a BS. The transceiver 802 and the processor 806 may interact with each other so as to perform the operations with respect to the BS described in FIGS. 1-7.

In some embodiments of the present application, the apparatus 800 may further include at least one non-transitory computer-readable medium.

For example, in some embodiments of the present disclosure, the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 806 to implement the method with respect to the UE as described above. For example, the computer-executable instructions, when executed, cause the processor 806 interacting with transceiver 802, so as to perform the operations with respect to the UE described in FIGS. 1-7.

In some embodiments of the present disclosure, the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 806 to implement the method with respect to the BS as described above. For example, the computer-executable instructions, when executed, cause the processor 806 interacting with transceiver 802 to perform the operations with respect to the BS described in FIGS. 1-7.

Those having ordinary skill in the art would understand that the operations or steps of a method described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Additionally, in some aspects, the operations or steps of a method may reside as one or any combination or set of codes and/or instructions on a non-transitory computer-readable medium, which may be incorporated into a computer program product.

While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in other embodiments. Also, all of the elements of each figure are not necessary for the operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure.

In this document, the terms "includes, " "including, " or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a, " "an, " or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Also, the term "another" is defined as at least a second or more. The term "having" and the like, as used herein, are defined as "including. " Expressions such as "A and/or B" or "at least one of A and B" may include any and all combinations of words enumerated along with the expression. For instance, the expression "A and/or B" or "at least one of A and B" may include A, B, or both A and B. The wording "the first, " "the second" or the like is only used to clearly illustrate the embodiments of the present application, but is not used to limit the substance of the present application.

Claims

A user equipment (UE) , comprising:

a transceiver; and

a processor coupled to the transceiver, wherein the processor is configured to:

receive a first set of downlink control information (DCI) formats for scheduling a first set of physical downlink shared channels (PDSCHs) , wherein the first set of PDSCHs is associated with a first service;

receive a second set of DCI formats for scheduling a second set of PDSCHs, wherein the second set of PDSCHs is associated with a second service; and

transmit a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook comprising a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs, wherein the first HARQ-ACK sub-codebook is placed in front of the second HARQ-ACK sub-codebook in the HARQ-ACK codebook.
The UE of claim 1, wherein the HARQ-ACK codebook includes a downlink assignment indicator (DAI) indicated in a DCI format last received among the first set of DCI formats.
The UE of claim 1, wherein the size of the first HARQ-ACK sub-codebook is determined based on the value of a downlink assignment indicator (DAI) indicated in a DCI format last received among the first set of DCI formats.
The UE of claim 1, wherein the processor is further configured to determine a first sub-codebook size for the first HARQ-ACK sub-codebook based on a first set of HARQ-ACK sub-codebook sizes.
The UE of claim 4, wherein to determine the first sub-codebook size, the processor is configured to:

determine a second HARQ-ACK sub-codebook size based on the first set of PDSCHs; and

select, from the first set of HARQ-ACK sub-codebook sizes, a minimum value which is equal to or greater than the second HARQ-ACK sub-codebook size as the first sub-codebook size.
The UE of claim 1, wherein the processor is further configured to determine a second sub-codebook size for the second HARQ-ACK sub-codebook based on a second set of HARQ-ACK sub-codebook sizes.
The UE of claim 1, wherein the size of the first HARQ-ACK sub-codebook is equal to a first predetermined HARQ-ACK sub-codebook size.
The UE of claim 7, wherein the first predetermined HARQ-ACK sub-codebook size is configured by radio resource control (RRC) signaling or predefined.
The UE of claim 1, wherein the size of the second HARQ-ACK sub-codebook is equal to a second predetermined HARQ-ACK sub-codebook size.
The UE of claim 1, wherein the HARQ-ACK codebook is transmitted in a first uplink resource indicated by a DCI format last received among the first set of DCI formats.
The UE of claim 10, wherein the first uplink resource is different from a second uplink resource indicated by a DCI format penultimately received among the first set of DCI formats.
The UE of claim 1, wherein the second service is a multicast service, and the second set of DCI formats are group-common DCI formats and the second set of PDSCHs are group-common PDSCHs.
The UE of claim 1, wherein the first set of DCI formats are UE-specific DCI formats and the first set of PDSCHs are UE-specific PDSCHs in response to the first service being a unicast service; and the first set of DCI formats are group-common DCI formats and the first set of PDSCHs are group-common PDSCHs in response to the first service being a multicast service.
A base station (BS) , comprising:

a transceiver; and

a processor coupled to the transceiver, wherein the processor is configured to:

transmit, to a user equipment (UE) of a group of UEs, a first set of downlink control information (DCI) formats for scheduling a first set of physical downlink shared channels (PDSCHs) , wherein the first set of PDSCHs is associated with a first service;

transmit, to the group of UEs, a second set of DCI formats for scheduling a second set of PDSCHs, wherein the second set of PDSCHs is associated with a second service; and

receive, from the UE, a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook comprising a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs, wherein the first HARQ-ACK sub-codebook is placed in front of the second HARQ-ACK sub-codebook in the HARQ-ACK codebook.
A method for wireless communication performed by a base station (BS) , comprising:

transmitting, to a user equipment (UE) of a group of UEs, a first set of downlink control information (DCI) formats for scheduling a first set of physical downlink shared channels (PDSCHs) , wherein the first set of PDSCHs is associated with a first service;

transmitting, to the group of UEs, a second set of DCI formats for scheduling a second set of PDSCHs, wherein the second set of PDSCHs is associated with a second service; and

receiving, from the UE, a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook comprising a first HARQ-ACK sub-codebook for the first set of PDSCHs and a second HARQ-ACK sub-codebook for the second set of PDSCHs, wherein the first HARQ-ACK sub-codebook is placed in front of the second HARQ-ACK sub-codebook in the HARQ-ACK codebook.