Patent Description:
Wireless communications systems are widely deployed to provide various telecommunications services such as telephony, video, data, messaging, and broadcasts. Typical wireless communications systems may employ multiple-access technologies capable of supporting communications with multiple users by sharing available system resources (e.g., bandwidth, transmit power, and/or the like). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, single-carrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE/LTE-Advanced is a set of enhancements to the universal mobile telecommunications system (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

A wireless communications network may include a number of base stations (BSs) that can support communications for a number of user equipment (UEs). The downlink (or forward link) refers to the communications link from the BS to the UE, and the uplink (or reverse link) refers to the communications link from the UE to the BS. As will be described in more detail, a BS may be referred to as a Node B, a gNB, an access point (AP), a radio head, a transmit receive point (TRP), a New Radio (NR) BS, a <NUM> Node B, and/or the like.

The above multiple access technologies have been adopted in various telecommunications standards to provide a common protocol that enables different user equipment to communicate on a municipal, national, regional, and even global level.

<CIT> discloses a Tx UE that receives msg2 from a base station and obtains control information necessary for transmitting msg3 from the msg2. Since it is necessary for all of the rest of UEs within a group to receive msg3 (groupcast message), the UEs should know msg3 scheduling information. In order to simply obtain the msg3 scheduling information, it is able to make all UEs in the group receive the msg2. Hence, it is able to make all UEs in the group decode the msg2 using a group-RNTI. The group-RNTI should be shared with each other in advance. As an example, the group-RNTI can be generated based on a group ID. In order to make a plurality of UEs receive PDCCH related to the msg2, the PDCCH related to msg2 can be transmitted in a common search space. Or, in the aspect of a group-specific, the PDCCH related to the msg2 can be transmitted in a UE-specific search space. Yet, it is able to reduce blind decoding complexity by informing/fixing a search space in advance. The Tx UE uses the msg2 to generate and transmit the msg3, whereas the Rx UEs use the msg2 to decode the msg3. Hence, an object of the msg2 may vary according to a UE. Subsequently, if the groupcast msg3 is transmitted, both the base station and the Rx UE receive and decode the msg3. In this case, various situations may occur. There may exist an Rx UE or a base station succeeded in receiving the msg3 and an Rx UE or a base station failed to receive the msg3.

According to an aspect of the present disclosure, a method for wireless communication performed by a user equipment (UE) is provided according to appended claim <NUM>.

In another aspect of the present disclosure, a method for wireless communication performed by a base station (BS) is provided according to appended claim <NUM>.

In another aspect of the present disclosure, a UE for wireless communications is provided according to appended claim <NUM>.

In another aspect of the present disclosure, a base station (BS) for wireless communications is provided according to appended claim <NUM>.

Additional features and advantages will be described. Characteristics of the concepts disclosed, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures.

So that features of the present disclosure can be understood in detail, a particular description, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.

Various aspects of the disclosure are described more fully below with reference to the accompanying drawings. Based on the teachings one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth. It should be understood that any aspect of the disclosure disclosed may be embodied by one or more elements of a claim.

Several aspects of telecommunications systems will now be presented with reference to various apparatuses and techniques.

It should be noted that while aspects may be described using terminology commonly associated with <NUM> and later wireless technologies, aspects of the present disclosure can be applied in other generation-based communications systems, such as and including <NUM> and/or <NUM> technologies.

In new radio (NR), performance may be improved for some communication scenarios by using multi-user packets (MUPs), where data for multiple user equipments (UEs) may be multiplexed together in a single packet. For example, in scenarios where a small amount of data is communicated to the multiple UEs, such as a factory automation scenario, an Industrial Internet-of-Things (IIoT) scenario, a broadcast or multicast scenario, an evolved multimedia broadcast multicast service (eMBMS) scenario, a single-cell point-to-multipoint (SC-PTM) scenario, and/or the like, performance may be improved by aggregating the data in an MUP as opposed to transmitting the data via multiple packets. For example, such aggregation or concatenation of data in an MUP may improve coding gains as compared to the transmission of multiple packets. Additionally, or alternatively, downlink control overhead may be reduced because downlink control information (DCI) may be transmitted for the MUP instead of a DCI for multiple packets for different UEs.

Aspects of the present disclosure are directed to UE-assisted retransmission of MUPs. According to some aspects, multiple UEs receive an MUP from a base station. Each UE may transmit acknowledgment/negative acknowledgment (ACK/NACK) feedback in response to the received MUP. The base station may map the ACK/NACK feedback to the UEs. The base station may request one or more UEs associated with an ACK to retransmit at least a portion of the MUP. Aspects of the present disclosure may conserve network resources and computing resources of the base station and/or the UEs.

The network <NUM> may be a <NUM> or NR network or some other wireless network, such as an LTE network. A BS is an entity that communicates with user equipment (UEs) and may also be referred to as a base station, an NR BS, a Node B, a gNB, a <NUM> node B (NB), an access point, a transmit and receive point (TRP), and/or the like. Each BS may provide communications coverage for a particular geographic area.

A BS may provide communications coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "node B", "<NUM> NB", and "cell" may be used interchangeably.

In the example shown in <FIG>, a relay station 110d may communicate with macro BS 110a and a UE 120d in order to facilitate communications between the BS 110a and UE 120d.

The wireless network <NUM> may be a heterogeneous network that includes BSs of different types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/or the like. These different types of BSs may have different transmit power levels, different coverage areas, and different impact on interference in the wireless network <NUM>.

As an example, the BSs <NUM> (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and the core network <NUM> may exchange communications via backhaul links <NUM> (e.g., S1, etc.). Base stations <NUM> may communicate with one another over other backhaul links (e.g., X2, etc.) either directly or indirectly (e.g., through core network <NUM>). The UEs <NUM> (e.g., 120a, 120b, 120c) may communicate with the core network <NUM> through a communications link <NUM>.

The core network <NUM> may be an evolved packet core (EPC), which may include at least one mobility management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME may be the control node that processes the signaling between the UEs <NUM> and the EPC. All user IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may be connected to the network operator's IP services. The operator's IP services may include the Internet, the Intranet, an IP multimedia subsystem (IMS), and a packet-switched (PS) streaming service.

The core network <NUM> may provide user authentication, access authorization, tracking, IP connectivity, and other access, routing, or mobility functions. One or more of the base stations <NUM> or access node controllers (ANCs) may interface with the core network <NUM> through backhaul links <NUM> (e.g., S1, S2, etc.) and may perform radio configuration and scheduling for communications with the UEs <NUM>.

UEs <NUM> (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network <NUM>, and each UE may be stationary or mobile. A UE may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communications device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, biometric sensors/devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio), a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.

One or more UEs <NUM> may establish a protocol data unit (PDU) session for a network slice. In some cases, the UE <NUM> may select a network slice based on an application or subscription service. By having different network slices serving different applications or subscriptions, the UE <NUM> may improve its resource utilization in the wireless communications system <NUM>, while also satisfying performance specifications of individual applications of the UE <NUM>. In some cases, the network slices used by UE <NUM> may be served by an AMF (not shown in <FIG>) associated with one or both of the base station <NUM> or core network <NUM>. In addition, session management of the network slices may be performed by a session management function (SMF).

The BSs <NUM> (e.g., BSs 110a, 110b, 110c, 110d) may include an MUP retransmission request module <NUM> for transmitting a message requesting an MUP retransmission. For ease of explanation, only one BS 110a is shown as including the MUP retransmission request module <NUM>. The MUP retransmission request module <NUM> may be a component of each BS <NUM>. The MUP retransmission request module <NUM> may transmit an MUP physical downlink shared channel (PDSCH) communication (MUP-PDSCH) including multiple payloads to multiple UEs <NUM>. The MUP retransmission request module <NUM> may receive a negative acknowledgment (NACK) from a first UE <NUM> of the multiple UEs <NUM> in response to the MUP-PDSCH communication. The MUP retransmission request module <NUM> may also receive an acknowledgment (ACK) from a second UE <NUM> of the multiple UEs <NUM> in response to the MUP-PDSCH communication. Additionally, the MUP retransmission request module <NUM> may transmit, to the second UE <NUM> in response to receiving the NACK from the first UE <NUM> and the ACK from the second UE <NUM>, a first message requesting the second UE <NUM> to retransmit one or more payload (e.g., one or more payload portions) of the multiple payloads.

The UEs <NUM> (e.g., UEs 120a, 120b, 120c, 120d, 120e) may include an MUP retransmission module <NUM>. For ease of explanation, only one UE 120d is shown as including the MUP retransmission module <NUM>. The MUP retransmission module <NUM> may be a component of each UE <NUM>. The MUP retransmission module <NUM> may be configured for receiving a multi-user physical (MUP) downlink shared channel (PDSCH) communication comprising multiple payloads (e.g., multiple payload portions). The MUP retransmission module <NUM> may transmit an ACK in response to decoding the MUP-PDSCH communication. The MUP retransmission module <NUM> may receive a message requesting retransmission of at least one payload of the multiple payloads. Additionally, the MUP retransmission module <NUM> may transmit the payload(s) in response to the message.

Some UEs may be considered machine-type communications (MTC) or evolved or enhanced machine-type communications (eMTC) UEs. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communications link. Some UEs may be considered Internet-of-Things (IoT) devices, and/or may be implemented as NB-IoT (narrowband Internet-of-things) devices. Some UEs may be considered a customer premises equipment (CPE).

In this case, the UE <NUM> may perform scheduling operations, resource selection operations, and/or other operations described elsewhere as being performed by the base station <NUM>. For example, the base station <NUM> may configure a UE <NUM> via downlink control information (DCI), radio resource control (RRC) signaling, a media access control-control element (MAC-CE) or via system information (e.g., a system information block (SIB).

<FIG> shows a block diagram of a design <NUM> of the base station <NUM> and UE <NUM>, which may be one of the base stations and one of the UEs in <FIG>. The base station <NUM> may be equipped with T antennas 234a through 234t, and UE <NUM> may be equipped with R antennas 252a through 252r, where in general T ≥ <NUM> and R ≥ <NUM>.

At the base station <NUM>, a transmit processor <NUM> may receive data from a data source <NUM> for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS(s) selected for the UE, and provide data symbols for all UEs. Decreasing the MCS lowers throughput but increases reliability of the transmission. The transmit processor <NUM> may also process system information (e.g., for semi-static resource partitioning information (SRPI) and/or the like) and control information (e.g., channel quality indicator (CQI) requests, grants, upper layer signaling, and/or the like) and provide overhead symbols and control symbols. The transmit processor <NUM> may also generate reference symbols for reference signals (e.g., the cell-specific reference signal (CRS)) and synchronization signals (e.g., the primary synchronization signal (PSS) and secondary synchronization signal (SSS)).

At the UE <NUM>, antennas 252a through 252r may receive the downlink signals from the base station <NUM> and/or other base stations and may provide received signals to demodulators (DEMODs) 254a through 254r, respectively. A receive processor <NUM> may process (e.g., demodulate and decode) the detected symbols, provide decoded data for the UE <NUM> to a data sink <NUM>, and provide decoded control information and system information to a controller/processor <NUM>. In some aspects, one or more components of the UE <NUM> may be included in a housing.

On the uplink, at the UE <NUM>, a transmit processor <NUM> may receive and process data from a data source <NUM> and control information (e.g., for reports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) from the controller/processor <NUM>. The symbols from the transmit processor <NUM> may be precoded by a TX MIMO processor <NUM> if applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, and/or the like), and transmitted to the base station <NUM>. At the base station <NUM>, the uplink signals from the UE <NUM> and other UEs may be received by the antennas <NUM>, processed by the demodulators <NUM>, detected by a MIMO detector <NUM> if applicable, and further processed by a receive processor <NUM> to obtain decoded data and control information sent by the UE <NUM>. The receive processor <NUM> may provide the decoded data to a data sink <NUM> and the decoded control information to a controller/processor <NUM>. The base station <NUM> may include communications unit <NUM> and communicate to the core network <NUM> via the communications unit <NUM>. The core network <NUM> may include a communications unit <NUM>, a controller/processor <NUM>, and a memory <NUM>.

The controller/processor <NUM> of the base station <NUM>, the controller/processor <NUM> of the UE <NUM>, and/or any other component(s) of <FIG> may perform one or more techniques associated with MUP retransmission, as described in more detail elsewhere. For example, the controller/processor <NUM> of the base station <NUM>, the controller/processor <NUM> of the UE <NUM>, and/or any other component(s) of <FIG> may perform or direct operations of, for example, the processes of <FIG> and/or other processes as described. Memories <NUM> and <NUM> may store data and program codes for the base station <NUM> and UE <NUM>, respectively.

In some aspects, the UEs <NUM> may include means for receiving a multi-user physical (MUP) downlink shared channel (PDSCH) communication (MUPC) including multiple payloads; transmitting an acknowledgement (ACK) in response to decoding the MUPC; receiving a message requesting retransmission of at least one payload of the multiple payloads; and transmitting the at least one payload in response to the message.

In some aspects, a BSs <NUM> may include means for transmitting an MUPC including multiple payloads to multiple UEs; receiving a negative acknowledgement (NACK) from a first UE of the multiple UEs in response to the MUPC; receiving an ACK from a second UE of the multiple UEs in response to the MUPC; and transmitting, to the second UE in response to receiving the NACK from the first UE and the ACK from the second UE, a first message requesting the second UE to retransmit at least one payload of the multiple payloads.

In new radio (NR), performance may be improved for some communications scenarios by using multi-user packets (MUPs), where data for multiple UEs <NUM> is multiplexed together in the payload of a single packet. For example, in scenarios where a small amount of data is communicated to multiple UEs <NUM>, such as a factory automation scenario, an Industrial Internet-of-Things (IIoT) scenario, a broadcast or multicast scenario, an evolved multimedia broadcast multicast service (eMBMS) scenario, a single-cell point-to-multipoint (SC-PTM) scenario, and/or the like, performance may be improved by aggregating the data in an MUP. The aggregation of data in an MUP may improve coding gains and/or reduce downlink control overhead.

Aspects of the present disclosure are directed to UE-assisted retransmission for MUPs. According to some aspects, multiple UEs <NUM> receive an MUP from a base station <NUM>. Each UE <NUM> may transmit ACK/NACK feedback in response to the received MUP. The base station may map the ACK/NACK feedback to the UEs <NUM>. Additionally, the base station <NUM> may request one or more UEs <NUM> associated with an ACK to retransmit at least a portion of the MUP. Aspects of the present disclosure may conserve network resources and computing resources of the base station <NUM> and/or the UEs <NUM>.

<FIG> is a diagram illustrating an example <NUM> of an MUP design for NR, in accordance with various aspects of the present disclosure. In some cases, an MUP is referred to as a multi-user physical downlink shared channel (PDSCH) communication (MUPC). The MUPC may also be referred to as an MUP-PDSCH communication.

As shown in <FIG>, an MUPC may include multiple sub-headers. Together, the multiple sub-headers form an MUPC header <NUM>. A sub-header may include a UE ID identifying a specific UE <NUM>, such as a cell radio network temporary identifier (C-RNTI). Different sub-headers may include different UE IDs identifying different UEs <NUM>. For example, a first sub-header (e.g., shown as sub-header A) may identify a first UE <NUM> (e.g., shown as UE A), a second sub-header (e.g., shown as sub-header B) may identify a second UE <NUM> (e.g., shown as UE B), and a third sub-header (e.g., shown as sub-header C) may identify a third UE <NUM> (e.g., shown as UE C). Aspects of the present disclosure are not limited to an MUPC for three UEs. The MUPC may aggregate data for any number of UEs (e.g., two or more UEs).

Additionally, the MUPC may include a payload <NUM> that is aggregated from multiple payload portions (e.g., payload portion a, payload portion b, and payload portion c) corresponding to the multiple UEs <NUM> (e.g., UE A, UE B, and UE C). Each payload portion may be referred to as a transport block (TB). The different payload portions may carry data intended for different UEs <NUM>. In one example, a first UE <NUM> (e.g., UE A) may identify a sub-header including a UE identifier for the first UE <NUM>. The first UE <NUM> may then identify a payload portion that corresponds to the identified sub-header (e.g., payload portion A). Furthermore, the first UE <NUM> may obtain the data included in the identified payload portion. In this way, data for multiple UEs <NUM> may be carried in a single MUPC.

In some aspects, as shown in <FIG>, a sub-header may include a length field indicating a length (e.g., a size, a number of bits, a number of bytes, and/or the like) of a corresponding payload portion. Additionally, or alternatively, a sub-header may include a field indicating whether that sub-header is the last sub-header (shown as "Last SH Indicator"). One or more of these fields may identify an end of the sub-headers and a start of the payload portions. A UE <NUM> may identify a start of a payload portion intended for the UE <NUM> based on the start of the payload portions and a sum of all of the lengths indicated in sub-headers that occur before the sub-header that identifies the UE <NUM>. The UE <NUM> may identify an end of the payload portion intended for the UE <NUM> using the length indicated in the sub-header that identifies the UE <NUM>.

As further shown, a sub-header may include an acknowledgment or negative acknowledgment (ACK/NACK) resource indicator (ARI). The ARI may identify (e.g., by itself or in combination with other information) a physical uplink control channel (PUCCH) resource in which the UE <NUM>, identified in the sub-header, is to transmit ACK/NACK feedback for the MUPC (e.g., the payload portion, of the MUPC, that corresponds to the UE <NUM>). A base station <NUM> may configure the ARIs included in different sub-headers to indicate different PUCCH resources, such that different UEs <NUM> transmit ACK/NACK feedback for the MUPC in different PUCCH resources (e.g., different time resources, different symbols, different slots, different subframes, different frequency resources, different resource blocks, and/or the like). In this way, the base station <NUM> may map ACK/NACK feedback to a UE <NUM> based on the PUCCH resource in which the ACK/NACK feedback is received.

In some aspects, the header <NUM> of the MUPC and the payload <NUM> of the MUPC may be included in a PDSCH payload. Additionally, or alternatively, the header of the MUPC (e.g., all of the sub-headers) may be included in a physical layer header (e.g., rather than a media access control (MAC) header), thereby allowing the header to be processed more quickly by the UEs <NUM> and reducing latency. In some aspects, each of the sub-headers may be the same size as one another. Additionally, or alternatively, the header may be a fixed or pre-configured size across multiple MUPCs. Thus, the sub-headers may include one or more reserved bits (e.g., filler bits) to achieve such alignment and reduce complexity. Alternatively, different sub-headers included in a header may have different sizes. Additionally, or alternatively, different headers included in different MUPCs may have different sizes. In this way, an MUPC may be flexibly configured (e.g., depending on a number of UEs <NUM> for which the MUPC is intended).

As shown by reference number <NUM>, in some aspects, an MUPC may have a first format where the sub-headers are grouped consecutively at the beginning of the MUPC. Additionally, or alternatively, if the MUPC is transmitted using multiple code blocks, the sub-headers may be included in a first code block (e.g., an initial code block or a first code block in time) of the MUPC. As such, the sub-headers may occur closer in time to a demodulation reference signal (DMRS), which may improve reliability of reception of the sub-headers. Furthermore, reducing a time between sub-headers and a DMRS may reduce an amount of data to be processed by UEs <NUM> because a UE <NUM> may process the sub-headers to determine whether there is a payload portion for the UE <NUM>. As shown by reference number <NUM>, in some aspects, an MUPC may have a second format where each sub-header is located immediately before a respective payload portion corresponding to that sub-header.

In some aspects, a DCI (not shown in <FIG>) may schedule and/or activate an MUPC. The DCI may be transmitted on a downlink control channel, such as a physical downlink control channel (PDCCH)). The DCI may include a group-radio network temporary identifier (RNTI) assigned to a group of UEs <NUM>. A UE <NUM> included in the group may determine that the DCI includes information for the UE <NUM> based on the group-RNTI. For example, the DCI may be descrambled based on the group-RNTI. Thus, the DCI may include the group-RNTI for the group of UEs <NUM> (e.g., a group-specific RNTI), and the MUPC sub-headers may include UE-specific RNTIs. Accordingly, each UE <NUM> configured with the group-RNTI may decode the PDSCH (e.g., the header <NUM> and payload <NUM> of the MUPC). As described above, by parsing the header <NUM>, a UE <NUM> may determine if it is being addressed and identify a corresponding payload portion (e.g., TB).

In some aspects, the DCI may include scheduling information and/or control information for the MUPC, which may indicate PDSCH resources that carry the MUPC, a modulation and coding scheme (MCS) for the MUPC, and/or the like. Additionally, or alternatively, the MUPC may be pre-scheduled using semi-persistent scheduling (SPS) (e.g., where scheduling information may be indicated in a radio resource control (RRC) message), and the UE <NUM> may activate and/or deactivate monitoring for the MUPC based at least in part on the DCI. In some aspects, the DCI may be a same format, size, and/or the like as unicast DCI, thereby reducing complexity.

In one configuration, a UE <NUM> configured to monitor a group-RNTI may decode data for other UEs <NUM> in the MUPC, when attempting to decode its own data. In some cases, the UE <NUM> may not be served by a particular MUPC. Still, the UE <NUM> is unaware of whether it is served by the particular MUPC until the UE <NUM> decodes the header <NUM>. In some aspects, a DCI piggyback design may separate the header <NUM> from the payload out of MUP-PDSCH. That is, the header <NUM> may be separately encoded from the payload <NUM>. Radio resource control (RRC) signaling may configure the UE <NUM> to decode the payload <NUM>.

<FIG> is a diagram illustrating an example <NUM> of UE-assisted full MUPC retransmission, in accordance with various aspects of the present disclosure. As shown in <FIG>, a first UE <NUM> (e.g., shown as UE0), a second UE <NUM> (e.g., shown as UE1), and a third UE <NUM> (e.g., shown as UE2) may be configured as a mutual assisting group. Additionally, the first, second, and third UEs <NUM> may be configured with a group-RNTI.

In one example, at a first time period (T1), a base station <NUM> (e.g., a gNB) may transmit a first DCI <NUM> for an MUPC <NUM>, in a similar manner as described in connection with <FIG>. The first DCI <NUM> may correspond to the group-RNTI, such that each UE <NUM> configured with the group-RNTI may receive and decode the first DCI <NUM>.

Each UE <NUM> configured with the group-RNTI may determine, or attempt to determine, whether a sub-header of the MUPC <NUM> includes a UE-ID of the UE <NUM>. Additionally, each UE <NUM> configured with the group-RNTI may attempt to identify or decode a payload portion corresponding to the sub-header including the UE-ID. Such an attempt may be successful, or may fail, and the UE <NUM> may selectively transmit ACK/NACK feedback based on whether the attempt succeeded or failed.

In the example of <FIG>, the first, second, and third UEs <NUM> belong to the same group and are configured with a same group-RNTI. At a second time period (T2), the base station <NUM> transmits the MUPC <NUM> to the first, second, and third UEs <NUM>. Additionally, at the second time period (T2), the first, second, and third UEs <NUM> attempt to decode the MUPC <NUM> based on the first DCI <NUM>. In the current example, a payload <NUM> of the MUPC <NUM> includes a first payload portion (e.g., shown as TB to UE0), a second payload portion (e.g., shown as TB to UE1), and a third payload portion (e.g., shown as TB to UE2). Each payload portion of the payload <NUM> may correspond to a different UE <NUM> configured with the group-RNTI. For example, the first payload portion (e.g., TB to UE0) corresponds to the first UE (e.g., UE0).

As described above, at the second time period (T2), each UE <NUM> may receive and attempt to decode the MUPC <NUM>. As described, by parsing the header <NUM>, a UE <NUM> can identify a portion of the payload <NUM> designated for itself. In the example of <FIG>, the first UE <NUM> fails to decode or receive the MUPC <NUM>. Therefore, the first UE <NUM> transmits a NACK <NUM> to the base station <NUM> at a third time period (T3). Additionally, the second and third UEs <NUM> successfully receive and decode the MUPC <NUM>. Therefore, each one of the second and third UEs <NUM> transmits an ACK <NUM> to the base station <NUM> (T3).

In one configuration, the UEs <NUM> may identify a PUCCH resource, for acknowledging receipt (e.g., ACK/NACK) of the payload portion based on a UE-specific ARI included in the sub-header of the MUPC <NUM> that identifies the UE <NUM>. The PUCCH resource may also be identified based on a common ARI included in the first DCI <NUM>. For example, the UE <NUM> may determine the PUCCH resource as a function of the common ARI and the UE-specific ARI.

In one configuration, at time period T3, each UE <NUM> transmits an ACK <NUM> if the UE <NUM> has decoded the entire payload <NUM> (e.g., each payload portion) of the MUPC <NUM>, as opposed to only decoding a payload portion designated for the UE <NUM>. For example, in order to transmit the ACK <NUM>, the second UE <NUM> may be specified to successfully decode the payload portion designated for the first UE <NUM> (e.g., TB for UE0), the payload portion designated for the second UE <NUM> (e.g., TB for UE1), and the payload portion designation for the third UE <NUM> (e.g., TB for UE2).

In another configuration, a payload portion may not be designated for a UE <NUM>. In this configuration, the header <NUM> may still include a sub-header for the UE <NUM>. The UE <NUM> may decode the sub-header to determine that a payload portion is not designated for the UE <NUM>. In this configuration, the UE <NUM> without a designated payload portion may be referred to as an assisting-only UE. Additionally, in this configuration, the assisting-only UE <NUM> transmits an ACK <NUM> if it has successfully decoded each payload portion of the payload <NUM>.

In the example of <FIG>, based on the NACK <NUM> received from the first UE <NUM>, the base station <NUM> determines the first UE <NUM> failed to receive or decode the MUPC <NUM>. Additionally, based on the ACK <NUM> received from the second and third UEs <NUM>, the base station <NUM> determines the second and third UEs <NUM> successfully received and decoded MUPC <NUM>. Therefore, the second and third UEs <NUM> have successfully received and decoded the payload portion of the first UE <NUM>.

In response to the ACKs <NUM> from the second and third UEs <NUM> and the NACK <NUM> from the first UE <NUM>, at a fourth time period (T4), the base station <NUM> transmits a message to the second and/or third UEs <NUM> requesting retransmission of the MUPC <NUM>. In one configuration, the message is a second DCI <NUM> associated with the group-RNTI. The second DCI <NUM> may include a field to trigger the retransmission. The field may be an added field or a repurposed field. A downlink channel communication, such as a PDSCH, is not associated with the second DCI <NUM>.

The retransmission may be a full retransmission, where the entire MUPC <NUM> is retransmitted. Alternatively, the retransmission may be a partial retransmission, where only a portion of the MUPC is retransmitted. A hybrid automatic repeat request (HARQ) process ID and an NDI included in the second DCI <NUM> may indicate whether the retransmission is full or partial. That is, the HARQ process ID and the NDI may identify one or more payload portions for retransmission. Additionally, the second DCI identifies one or more resources for the retransmission. In one configuration, a time domain resource assignment (TDRA) or a frequency domain resource assignment (FDRA) in the second DCI <NUM> may be used for the retransmission.

As described above, in <FIG>, the base station <NUM> transmits the second DCI <NUM> to the first, second, and third UEs <NUM> at the fourth time period (T4). As described, <FIG> is an example of a full retransmission. Therefore, a format of the second DCI <NUM> matches a format of the first DCI <NUM>. For example, the HARQ process ID and the NDI of the second DCI <NUM> match the HARQ process ID and the NDI of the first DCI <NUM>.

In one configuration, a UE <NUM> that successfully decoded an initial MUPC performs a retransmission in response to receiving the second DCI <NUM> if a slot offset (K0) is greater than zero (e.g., the PDSCH and the PDCCH are in different slots).

In the example of <FIG>, the second and/or third UEs <NUM> receive the second DCI <NUM> and determine that both the HARQ process ID and the NDI of the second DCI <NUM> match the HARQ process ID and the NDI of the first DCI <NUM>. As a result, the second and/or third UEs <NUM> determine the second DCI <NUM> is an assisted retransmission grant for a full retransmission. In the example of <FIG>, K0 is greater than zero for the second and third UEs <NUM>.

In response to receiving the second DCI <NUM>, the second and/or third UEs <NUM> may retransmit the MUPC <NUM> at a fifth time period (T5). The second and/or third UEs <NUM> are not specified to change the MUPC <NUM>, such that the first UE <NUM> may soft combine the retransmitted MUPC <NUM>. Still, this comes at a cost to the second and third UEs because both the second and third payload portions are retransmitted to each of the UEs <NUM>. In this example, none of the UEs <NUM> in the group-RNTI have a use for the second or third payload portions.

The second and/or third UEs <NUM> may retransmit the MUPC <NUM> via one or more resources indicated in the second DCI <NUM>. Additionally, the second and/or third UEs <NUM> may re-encode the MUPC <NUM> and rate match the re-encoded MUPC <NUM> to the one or more indicated resources. The redundancy version identifier (RVID) used to retransmit the MUPC <NUM> matches the RVID of the first DCI <NUM>.

As described, both the second and third UEs <NUM> may retransmit the MUPC <NUM>. In some examples, the second UE <NUM> may receive the MUPC <NUM> retransmission from the third UE <NUM>, and vice versa. In such examples, the second and third UEs <NUM> refrain from transmitting an ACK <NUM> or NACK <NUM> for the MUPC <NUM> retransmission.

The retransmissions from the second and/or third UEs <NUM> may follow a PDSCH waveform in a system frame number (SFN) fashion.

In the example of <FIG>, at the fifth time period (T5), the first UE <NUM> receives the second DCI <NUM> and treats the second DCI <NUM> as a retransmission grant for itself. The first UE <NUM> may combine the retransmitted MUPC <NUM> with the initial MUPC <NUM> based on a log-likelihood ratio (LLR) method. That is, the first UE <NUM> may apply soft combining on the retransmitted MUPC <NUM> and the initial MUPC <NUM>. From the perspective of the first UE <NUM>, the source of the MUPC <NUM> retransmission is transparent.

In one configuration, the first UE <NUM> transmits an ACK <NUM> or a NACK <NUM> to the base station <NUM> in response to the MUPC retransmission. The second DCI <NUM> may provide an uplink grant for transmitting the ACK <NUM> or the NACK <NUM> at a sixth time period (T6). In some aspects, multiple MUPC <NUM> retransmissions may be performed by one or more UEs <NUM> that successfully decoded an initial transmission of the MUPC <NUM>.

The example of <FIG> is an example of macro diversity. In addition to, or as an alternate to, the aspects described in <FIG>, the second and/or third UEs <NUM> may detect the NACK <NUM> transmitted by the first UE <NUM>. A retransmission of the MUPC <NUM> may be triggered in response to detecting the NACK <NUM> transmitted by the first UE <NUM>.

<FIG> is a diagram illustrating another example <NUM> of UE-assisted full MUPC retransmission, in accordance with various aspects of the present disclosure. As shown in <FIG>, at time period T1, a base station <NUM> may transmit a first DCI <NUM> to a first UE <NUM>, second UE <NUM>, and third UE <NUM>, as described in <FIG>. Additionally, as described in <FIG>, at time period T2, the base station <NUM> may transmit the MUPC <NUM> to the first, second, and third UEs <NUM>.

In the example of <FIG>, at time period T3, the first and third UEs <NUM> transmit a NACK <NUM> in response to the MUPC <NUM> (e.g., an initial MUPC <NUM> transmission). Additionally, at time period T3, the second UE <NUM> transmits an ACK <NUM> in response to the initial MUPC <NUM> transmission. In response to the ACK <NUM> from the second UE <NUM> and the NACKs <NUM> from the first and third UEs <NUM>, at time period T4, the BS <NUM> transmits a second DCI <NUM> to the first, second, and third UEs <NUM>.

The second UE <NUM> identifies the second DCI <NUM> as a retransmission request and retransmits the MUPC <NUM>, in a similar manner as described in connection with <FIG>. Additionally, each one of the first and the third UEs <NUM> receives the second DCI <NUM> and treats the second DCI <NUM> as a retransmission grant itself. At time period T5, the first and third UEs <NUM> receive the MUPC <NUM> retransmission from the second UE <NUM>, in a similar manner as described in connection with <FIG>.

As described, the retransmission may be a partial retransmission (e.g., selective retransmission). <FIG> is a diagram illustrating an example <NUM> of UE-assisted partial MUPC retransmission, in accordance with various aspects of the present disclosure. As shown in <FIG>, at time period T1, a base station <NUM> may transmit a first DCI <NUM> to a first UE <NUM>, second UE <NUM>, and third UE <NUM>, in a similar manner as described in connection with <FIG>. Additionally, in a similar manner as described in connection with <FIG>, at time period T2, the base station <NUM> may transmit the MUPC <NUM> to the first, second, and third UEs <NUM>.

In the example of <FIG>, at time period T3, the first UE <NUM> transmits a NACK <NUM> in response to the initial MUPC <NUM> transmission. Additionally, at time period T3, the second and third UEs <NUM> transmits an ACK <NUM> in response to the initial MUPC <NUM> transmission. In response to the ACKs <NUM> from the second and third UEs <NUM> and the NACK <NUM> from the first UE <NUM>, the BS <NUM> initiates a selective retransmission procedure.

In the example of <FIG>, for the selective retransmission procedure, the BS <NUM> identifies the one or more payload portions that were not received by one or more UEs <NUM>. In this example, the first UE <NUM> did not receive the first payload portion (e.g., TB for UE0). In response, the BS <NUM> transmits a message requesting the second and/or third UEs <NUM> to only retransmit the portion of the MUPC <NUM> corresponding to the first payload portion (e.g., the first payload portion and the corresponding sub-header).

In one configuration, at time period T4, the BS transmits a second DCI <NUM> to the second and/or third UEs <NUM> because the second and third UEs transmitted ACKs <NUM> in response to the initial MUPC <NUM>. The second DCI <NUM> may be associated with the group-RNTI of the first, second, and third UEs <NUM>. The content of the second DCI <NUM> distinguishes the second DCI <NUM> from an initial transmission grant (e.g., the first DCI <NUM>, as described in <FIG>). That is, the content of the second DCI <NUM> identifies the second DCI <NUM> as a partial retransmission request. In one configuration, a HARQ process ID and NDI of the second DCI <NUM> identifies specific payload portions (e.g., specific TBs) for the retransmission. Additionally, or alternatively, a separate bit field of the second DCI <NUM> may identify specific payload portions (e.g., specific TBs) for the retransmission.

As shown in <FIG>, at time period T5, the second and/or third UEs <NUM> may retransmit the payload portion identified in the second DCI <NUM> (e.g., the first payload portion) via resources identified in a third DCI <NUM>. The resources may include an RVID, a modulation coding scheme (MCS), and/or the like. The partial retransmissions from the second and/or third UEs <NUM> may follow a PDSCH waveform in a system frame number (SFN) fashion.

In one configuration, as shown in <FIG>, at time period T4, the BS <NUM> transmits a third DCI <NUM> to the first UE <NUM> because the first UE <NUM> transmitted the NACK <NUM> in response to the initial MUPC <NUM> transmission. The NDI of the third DCI <NUM> may be flipped or the HARQ process ID of the third DCI <NUM> may be different from the HARQ process ID of the first DCI <NUM>. The first UE <NUM> may treat the third DCI <NUM> as a grant for a new transmission, where the new transmission is received according to the information in the third DCI <NUM>.

In the example of <FIG>, at time period T5, the first UE <NUM> receives the retransmission from the second and or third UEs <NUM>. Because the second DCI <NUM> requests one or more specific payload portions, the first UE <NUM> may not perform soft combining on the retransmitted payload portion and the initial payload portion. From the perspective of the first UE <NUM>, the source of the retransmitted payload portion is transparent. At time period T6, the first UE <NUM> may transmit an ACK <NUM> or a NACK <NUM> to the BS <NUM> in response to receiving the retransmitted payload portion.

As indicated above, <FIG>, <FIG>, <FIG>, and <FIG> are provided as examples. Other examples may differ from what is described with respect to <FIG>, <FIG>, <FIG>, and <FIG>.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a UE, in accordance with various aspects of the present disclosure. The example process <NUM> is an example of wireless communications, by a UE (user equipment), such as one of the UEs <NUM> described in <FIG> or by a MUP retransmission module <NUM> as described in <FIG>. The process <NUM> may include.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a UE, in accordance with various aspects of the present disclosure. The example process <NUM> is an example of a multi-user packet for user equipment assisted retransmission.

As shown in <FIG>, in some aspects, the process <NUM> may include receiving a multi-user physical (MUP) downlink shared channel (PDSCH) communication (MUPC) comprising a plurality of payloads (block <NUM>). For example, the UE (e.g., using the antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) can receive a multi-user physical (MUP) downlink shared channel (PDSCH) communication (MUPC).

As shown in <FIG>, in some aspects, the process <NUM> may include transmitting an acknowledgement (ACK) in response to decoding the MUPC (block <NUM>). For example, the UE (e.g., using the antenna <NUM>, MOD <NUM>, TX MIMO processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) can transmit an acknowledgement (ACK).

As shown in <FIG>, in some aspects, the process <NUM> may include receiving a message requesting retransmission of at least one payload of the plurality of payloads (block <NUM>). For example, the UE (e.g., using the antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) can receive a message requesting retransmission.

As shown in <FIG>, in some aspects, the process <NUM> may include transmitting the at least one payload in response to the message (block <NUM>). For example, the UE (e.g., using the antenna <NUM>, MOD <NUM>, TX MIMO processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) can transmit the at least one payload.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a BS, in accordance with various aspects of the present disclosure. The example process <NUM> is an example of wireless communications, by a BS, such as the BS <NUM> as described in <FIG> or by a MUP retransmission request module <NUM> as described in <FIG>. The process <NUM> includes.

<FIG> is a diagram illustrating an example process <NUM> performed, for example, by a base station, in accordance with various aspects of the present disclosure. The example process <NUM> is an example of a multi-user packet for user equipment assisted retransmission.

As shown in <FIG>, in some aspects, the process <NUM> may include transmitting a multi-user physical (MUP) downlink shared channel (PDSCH) communication (MUPC) comprising a plurality of payloads to a plurality of UEs (block <NUM>). For example, the base station (e.g., using the antenna <NUM>, MOD <NUM>, TX MIMO processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) can transmit a multi-user physical (MUP) downlink shared channel (PDSCH) communication (MUPC).

As shown in <FIG>, in some aspects, the process <NUM> may include receiving a negative acknowledgement (NACK) from a first UE of the plurality of UEs in response to the MUPC (block <NUM>). For example, the base station (e.g., using the antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, the controller/processor <NUM>, memory <NUM>, and/or the like) can receive a negative acknowledgement (NACK) from a first UE of the plurality of UEs in response to the MUPC.

As shown in <FIG>, in some aspects, the process <NUM> may include receiving an acknowledgement (ACK) from a second UE of the plurality of UEs in response to the MUPC (block <NUM>). For example, the base station (e.g., using the antenna <NUM>, DEMOD <NUM>, MIMO detector <NUM>, receive processor <NUM>, the controller/processor <NUM>, memory <NUM>, and/or the like) can receive an acknowledgement (ACK) from a second UE of the plurality of UEs in response to the MUPC.

As shown in <FIG>, in some aspects, the process <NUM> may include transmitting, to the second UE in response to receiving the NACK from the first UE and the ACK from the second UE, a first message requesting the second UE to retransmit at least one payload of the plurality of payloads (block <NUM>). For example, the base station (e.g., using the antenna <NUM>, MOD <NUM>, TX MIMO processor <NUM>, transmit processor <NUM>, controller/processor <NUM>, memory <NUM>, and/or the like) can transmit a first message requesting the second UE to retransmit at least one payload of the plurality of payloads.

As used, the term "component" is intended to be broadly construed as hardware, firmware, and/or a combination of hardware and software. As used, a processor is implemented in hardware, firmware, and/or a combination of hardware and software.

Some aspects are described in connection with thresholds. As used, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and/or the like.

It will be apparent that systems and/or methods described may be implemented in different forms of hardware, firmware, and/or a combination of hardware and software. Thus, the operation and behavior of the systems and/or methods were described without reference to specific software code-it being understood that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description.

Claim 1:
A method (<NUM>) for wireless communications performed by a user equipment, UE, comprising:
receiving (<NUM>) a multi-user physical, MUP, downlink shared channel, PDSCH, communication, MUPC, comprising a plurality of payloads;
transmitting (<NUM>) an acknowledgement, ACK, in response to decoding the MUPC;
receiving (<NUM>) a message requesting retransmission of at least one payload of the plurality of payloads, wherein the message comprises a group-radio network temporary identifier, RNTI, downlink control information, DCI, comprising a field for triggering the retransmission;
retransmitting (<NUM>) the at least one payload to one or more other UEs in response to the message; and
determining a resource for the retransmission based on a time domain resource assignment, TDRA, or a frequency domain resource assignment, FDRA, in the group-RNTI DCI.