Side link multicast method and network node thereof

Abstract

The method includes a processor of a first UE receiving a first set of information for a user group having user equipment members, the first set of information including information for mapping a side link channel resource for each of the user equipment members for the user group to perform multicast communication via a side link, the first UE being a user equipment member of the user group. The method also includes receiving a second set of information for transmitting data within the multicast communication, the second set of information including updated information of the first set of information specific to the first UE; initiating a first transmission process based on the first set of information to transmit a first data block to the user group for multicast communication via a side link; and adapting the first transmission process of the first data block based on the second set of information.

Description

Technical Field

[0001] One or more example embodiments relate to a wireless communication network. Background Art

[0002] Wireless communication networks use multicast or groupcast messages that allow devices to communicate with each other. These messages can include defined groups of devices. Summary of the invention

[0003] At least one example embodiment is directed to a method.

[0004] In an exemplary embodiment, the method includes receiving, by at least one first processor of a first user equipment (UE), a first set of information for a user group having user equipment members, the first set of information including information for mapping side link channel resources for each of the user equipment members for the user group to perform multicast communication via a side link, the first UE being a user equipment member of the user group; receiving, by at least one first processor, a second set of information for transmitting data within the multicast communication, the second set of information including updated information of the first set of information specific to the first UE; initiating, by at least one first processor, a first transmission process based on the first set of information to transmit a first data block to the user group for multicast communication via a side link; and adapting, by at least one first processor, the first transmission process of the first data block based on the second set of information.

[0005] In an example embodiment, the first transmission process is a hybrid automatic repeat request (HARQ) process over a sidelink.

[0006] In one example embodiment, the sidelink channel resource is a Physical Sidelink Feedback Channel (PSFCH).

[0007] In an example embodiment, the receiving of the second set of information can occur during one of: before initiating the first transmission process, or after initiation of the first transmission process and during a time period in which the first transmission process is ongoing.

[0008] In an example embodiment, the method further comprises: receiving first feedback information from the user group, wherein the adapting of the first transmission process comprises determining whether to continue the first transmission process based on the second group information and the first feedback information.

[0009] In an exemplary embodiment, the first feedback information is HARQ feedback information, and the HARQ feedback information includes one of acknowledgment, negative acknowledgment, or discontinuous transmission (DTX) information.

[0010] In an example embodiment, the adapting of the first transmission process further comprises initiating a second transmission process based on the second group information to transmit a second data block to a user group for multicast communication over the side link.

[0011] In an example embodiment, the second transmission process includes an indicator indicating to the user group that the first data block in the first transmission process and the second data block in the second transmission process are the same data block.

[0012] In an exemplary embodiment, the method further includes: receiving second feedback information from at least one first user device among the user device members of the user group that has received the first data block of the first transmission process, the second feedback information indicating that the at least one first user device will ignore the second transmission process.

[0013] In an exemplary embodiment, the method further includes: after initiation of the first transmission process, receiving DTX feedback information from at least one first user equipment among the user equipment members; initiating reporting of the identity of at least one first user equipment from the access layer to the application layer at the first UE; and / or ignoring at least one first user equipment during the remaining part of the first transmission process.

[0014] At least another example embodiment relates to a first network node.

[0015] In an example embodiment, a first network node includes a memory including computer-readable instructions; and at least one first processor configured to read and execute the computer-readable instructions to receive a first set of information for a user group having user device members, the first set of information including information for mapping side link channel resources for each of the user device members for the user group to perform multicast communication via the side link, the first network node being a user device member of the user group, receiving a second set of information for transmitting data within the multicast communication, the second set of information including updated information of the first set of information specific to the first network node, initiating a first transmission process based on the first set of information to transmit a first data block to the user group for multicast communication via the side link, and adapting the first transmission process of the first data block based on the second set of information.

[0016] In an example embodiment, the first transmission process is a hybrid automatic repeat request (HARQ) process over a sidelink.

[0017] In one example embodiment, the sidelink channel resource is a Physical Sidelink Feedback Channel (PSFCH).

[0018] In an example embodiment, the at least one first processor is configured to receive the second set of information during one of: before initiating the first transmission process, or after initiation of the first transmission process and during a time period in which the first transmission process is ongoing.

[0019] In an example embodiment, the at least one first processor is further configured to: receive first feedback information from the user group, wherein the adapting of the first transmission process includes determining whether to continue the first transmission process based on the second group information and the first feedback information.

[0020] In an exemplary embodiment, the first feedback information is HARQ feedback information, and the HARQ feedback information includes one of acknowledgment, negative acknowledgment, or discontinuous transmission (DTX) information.

[0021] In an example embodiment, the at least one first processor is configured to adapt the first transmission process by initiating a second transmission process based on the second group information to transmit a second data block to a user group for multicast communication over a sidelink.

[0022] In an example embodiment, the second transmission process includes an indicator indicating to the user group that the first data block in the first transmission process and the second data block in the second transmission process are the same data block.

[0023] In an exemplary embodiment, the at least one first processor is further configured to receive second feedback information from at least one first user device among the user device members of the user group, which has received the first data block of the first transmission process, the second feedback information indicating that the at least one first user device will ignore the second transmission process.

[0024] In an example embodiment, the at least one first processor is further configured to: after initiation of the first transmission process, receive DTX feedback information from at least one first user equipment among the user equipment members, initiate reporting of the identity of the at least one first user equipment from the access layer to the application layer at the first UE, and / or ignore the at least one first user equipment during the remaining part of the first transmission process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Example embodiments will be more fully understood from the detailed description and accompanying drawings given below, in which like elements are represented by like reference numerals, which are given by way of example only and thus do not limit the present disclosure.

[0026] Figure 1 illustrates a simplified diagram of a wireless communication network for explaining an example embodiment;

[0027] Figure 2 illustrates a block diagram of a base station according to an example embodiment;

[0028] Figure 3 illustrates a block diagram of a user equipment (UE) according to an example embodiment;

[0029] Figure 4 A method of initiating a communication process according to an example embodiment is illustrated; and

[0030] Figure 5 A signaling diagram according to an example embodiment is illustrated.

[0031] It should be noted that these figures are intended to illustrate the general characteristics of methods, structures, and / or materials utilized in certain example embodiments, as well as to supplement the written description provided below. However, these drawings are not drawn to scale and may not accurately reflect the precise structure or performance characteristics of any given embodiment, and should not be interpreted as defining or limiting the range of values ​​or characteristics included in the example embodiments. The use of similar or identical reference numerals in the various drawings is intended to indicate the presence of similar or identical elements or features. DETAILED DESCRIPTION

[0032] Various example embodiments will now be described more fully with reference to the accompanying drawings, in which some example embodiments are shown.

[0033] Detailed illustrative embodiments are disclosed herein. However, the specific structural and functional details disclosed herein are merely intended for the purpose of describing the exemplary embodiments. However, the exemplary embodiments may be embodied in many alternative forms and should not be construed as being limited to the embodiments set forth herein.

[0034] It should be understood that the exemplary embodiments are not intended to be limited to the specific forms disclosed. On the contrary, the exemplary embodiments will cover all modifications, equivalents, and substitutions that fall within the scope of the present disclosure. In the description throughout the drawings, the same numbers represent the same elements.

[0035] Although one or more example embodiments may be described from the perspective of a radio network element (e.g., a gNB), a user equipment, etc., it should be understood that one or more example embodiments discussed herein may be performed by one or more processors (or processing circuitry) at an applicable device. For example, according to one or more example embodiments, at least one memory may include or store computer program code, and at least one storage and computer program code may be configured to cause, together with at least one processor, a radio network element (or user equipment) to perform the operations discussed herein.

[0036] It should be understood that various example embodiments may be used in combination.

[0037] Introduction:

[0038] In an example embodiment, sidelink (SL) multicast with hybrid automatic repeat request (HARQ) feedback may be implemented using Option 2 as follows:

[0039] - In an example embodiment, PSFCH resources for individual receiving user equipment (Rx UE) are derived using the group member IDs of the Rx UE and the transmitting user equipment (Tx UE);

[0040] - In an example embodiment, the Tx UE may use HARQ feedback option 2 only if the group size is not greater than the number of candidate PSFCH resources associated with the selected PSFCH resource. RANI assumes that RAN2 will handle the selection of the appropriate groupcast HARQ feedback option.

[0041] In an example embodiment: it is assumed that the V2X application layer provides the AS layer with accurate and up-to-date information about group size and member IDs.

[0042] discuss:

[0043] In an example embodiment, it is important that there is no mismatch in the derived PSFCH resources between the Tx UE and the Rx UE when using HARQ feedback option 2. Therefore, the group information (including member ID and group size) used to derive the PSFCH resources for individual group members must be the same or common to all group members.

[0044] Observation 1: The group information (including member ID and group size) used to derive PSFCH resources for individual group members must be the same or common to all group members.

[0045] Proposal 1: HARQ feedback option 2 uses common group information for PSFCH mapping.

[0046] In an example embodiment, a specific Tx UE of an ongoing SL HARQ process may use HARQ feedback option 2 for groupcast. In an example embodiment, this may be performed dynamically when the number of group members that are actually present in the vicinity of the Tx UE (within range) and are able to receive HARQ transmissions of the ongoing HARQ process is less than the group size given in the common group information used to derive PSFCH resources. In an example embodiment, this is due to, for example, mobility of individual group members and radio channel conditions. In an example embodiment, if the Tx UE is not provided with the latest information of group members present in the vicinity of the Tx UE (referred to as Tx UE-specific group information), the Tx UE may expect to receive HARQ feedback from all group members given in the common group information, including those group members that are not present in the vicinity of the Tx UE during the ongoing HARQ process. In an example embodiment, this may cause the Tx UE to continue to perform unnecessary HARQ retransmissions up to the maximum limit configured for the ongoing HARQ process and result in an overall failure of the ongoing HARQ process. In an example embodiment, this may further lead to unnecessary retransmissions at higher layers due to the failure of the HARQ process at the Tx UE. In an example embodiment, one option to address this issue is to have the Tx UE ignore or exclude those group members from which the Tx UE detects HARQ DTX for the remainder of the ongoing HARQ process. However, since HARQ DTX may not only occur to group members that are not present in the vicinity of the Tx UE, the option of ignoring or excluding group members that detect HARQ DTX may not be robust enough.

[0047] Observation 2: In an example embodiment, if the number of group members present in the vicinity (range) of the Tx UE during an ongoing HARQ process is smaller than the group size given in the common group information, the Tx UE may have to perform HARQ retransmissions under the maximum limit of the ongoing HARQ process.

[0048] In an example embodiment, the application layer at the Tx UE may have updated the knowledge of the group members present in the vicinity of the Tx UE in real time based on, for example, frequent exchanges of security or group management related messages.

[0049] Observation 3: In the example embodiment, the application layer at the Tx UE may have updated the knowledge of the group members present in the vicinity of the Tx UE based on, for example, frequent exchanges of security or group management related messages.

[0050] In an example embodiment, considering the availability of Tx UE-specific group information updated to the AS layer by the application layer at the Tx UE in real time, the Tx UE may be able to avoid unnecessary reception and retransmission of PSFCH for group members that are not present near the Tx UE in the ongoing HARQ process.

[0051] Proposal 2: In an example embodiment, a Tx UE in an ongoing HARQ process using HARQ feedback option 2 considers the available Tx UE-specific group information for HARQ operation.

[0052] Proposal 3: In an example embodiment, RAN2 sends LS to SA2 and keeps copying RANI to ensure that the V2X application layer provides common group information to all group members, and furthermore, checks and confirms the availability of updated UE-specific group information.

[0053] in conclusion:

[0054] In example embodiments, the following observations and suggestions are made in this document.

[0055] Observation 1: In the example embodiment, the group information (including member ID and group size) used to derive PSFCH resources for individual group members must be the same or common to all group members.

[0056] Observation 2: In an example embodiment, if the number of group members present in the vicinity (range) of the Tx UE during an ongoing HARQ process is smaller than the group size given in the common group information, the Tx UE may have to perform HARQ retransmissions under the maximum limit of the ongoing HARQ process.

[0057] Observation 3: In the example embodiment, the application layer at the Tx UE may have updated the knowledge of the group members present in the vicinity of the Tx UE based on, for example, frequent exchanges of security or group management related messages.

[0058] Proposal 1: In an example embodiment, HARQ feedback option 2 uses common group information for PSFCH mapping.

[0059] Proposal 2: In an example embodiment, a Tx UE in an ongoing HARQ process using HARQ feedback option 2 considers the available Tx UE-specific group information for HARQ operation.

[0060] Proposal 3: In an example embodiment, RAN2 transmits LS to SA2 and keeps copying RANI to ensure that the V2X application layer provides common group information to all group members, and furthermore, checks and confirms the availability of updated UE-specific group information.

[0061] Problems to be solved according to some current example embodiments:

[0062] In the current example embodiment, multicast over the side link (SL) or PC5 interface may use hybrid automatic repeat request (HARQ), where HARQ feedback of acknowledgment (ACK) / negative acknowledgment (NACK) / discontinuous transmission (DTX) is sent from individual Rx UEs of the user group on a dedicated physical side link feedback channel (PSFCH). The current example embodiment includes a dedicated physical side link feedback channel (PSFCH) that is determined based on a member identifier (ID) of an individual receiving (Rx) UE within the user group. In the current example embodiment, the PSFCH may also be determined based on the group size of the user group. In the example embodiment, the member ID and group size are provided by the application layer, as discussed in 3GPP TS23.287 (which is incorporated herein by reference in its entirety), as described below:

[0063] The QoS treatment described in clause 5.4.1.2 (above) applies to all group communications, i.e., application layer connectionless groups or application layer managed groups. In addition, the following apply:

[0064] The PFI and PC5 QoS parameters are negotiated during the Layer 2 Link Establishment procedure as described in clause 6.3.3.1 (3GPP TS 23.287) or during the Layer 2 Link Modification procedure as described in clause 6.3.3.4 (3GPP TS 23.288).

[0065] - If the V2X application layer provides the group size and member IDs for the application layer managed group, the V2X layer passes them to the AS layer for multicast control as defined in 3GPP TS 38.300 (which is incorporated herein by reference). It is assumed that the V2X application layer provides accurate and up-to-date information about the group size and member IDs.

[0066] Structural embodiment:

[0067] Figure 1A simplified diagram of a wireless communication network 10 is shown for explaining the current example embodiment. In the example embodiment, the network 10 is part of a third generation partnership project (3GPP) new radio (NR) access network. In the example embodiment, the 3GPP NR radio access deployment includes a base station (e.g., gNB 102) with a transmission and reception point (TRP) 102a, 102b, 102c. Each TRP 102a, 102b, 102c can be, for example, a remote radio head (RRH) or a remote radio unit (RRU), which includes at least, for example, a radio frequency (RF) antenna (or multiple antennas) or an antenna panel, and a radio transceiver for transmitting and receiving data within a geographic area. In the example embodiment, from the perspective that the TRP 102a, 102b, 102c is a smaller cell that communicates in conjunction with a larger cell (e.g., gNB 102), the TRP 102a, 102b, 102c is considered a secondary cell (SCell). The TRPs 102a, 102b, 102c provide cellular resources to user equipment (UE) 106a, 106b, 106c, 106d within the geographic coverage area. In some cases, in fifth generation (5G) cells, baseband processing may be divided between the TRPs 102a, 102b, 102c and the gNB 102. Alternatively, baseband processing may be performed at the gNB 102. Figure 1 In the example shown, TRPs 102a, 102b, 102c are configured to communicate with a user equipment or UE (e.g., UE 106a) via one or more transmit (TX) / receive (RX) beam pairs. The gNB 102 communicates with the network core 1, which is referred to as the new core in 3GPP NR.

[0068] The TRPs 102a, 102b, 102c may have independent schedulers, or the gNB 102 may perform joint scheduling between the TRPs 102a, 102b, 102c.

[0069] It should be understood that the gNB 102 and TRPs 102a, 102b, 102c can provide communication services to a relatively large number of UEs 106a, 106b, 106c, 106d within the coverage area of ​​the TRPs 102a, 102b, 102c. For clarity of the current example embodiment, the communication services (including the transmission and reception of wireless signals) will be directed to Figure 1 The present invention is discussed with respect to network 10, although it should be understood that network 10 may include any number of base stations (e.g., gNB 102), any number of secondary cells (e.g., TRP 102a) or no secondary cells, and any number of user devices (e.g., UE 106a, 106b, 106c, 106d).

[0070] Figure 2 A block diagram of a base station according to an example embodiment is shown, where the base station may be, for example, a gNB 102 (e.g., Figure 1 In example embodiments, other types of base stations are contemplated for use Figure 1 In the network 10 of , other types of base stations include the same structural elements described herein. In the example embodiment, as Figure 2 As shown, gNB 102 includes: a memory 240; a processor 220 connected to the memory 240; various interfaces 260 connected to the processor 220; and one or more antennas or antenna panels 265 connected to the various interfaces 260. The various interfaces 260 and antennas 265 may constitute a transceiver for transmitting / receiving data from / to gNB 102 or from / to multiple TRPs 102a, 102b, 102c, etc. via multiple wireless beams. As will be understood, depending on the implementation of gNB 102, gNB 102 may include more than Figure 2 Many more components are shown. However, it is not necessary to show all of these components in order to disclose an illustrative example embodiment.

[0071] The memory 240 may be a computer-readable storage medium that typically includes random access memory (RAM), read-only memory (ROM), and / or a permanent mass storage device, such as a disk drive. The memory 240 also stores an operating system and any other routines / modules / applications for providing the functionality of the gNB 102 to be executed by the processor 220 (e.g., functionality of the gNB, methods according to example embodiments, etc.). These software components may also be loaded into the memory 240 from a separate computer-readable storage medium using a drive mechanism (not shown). Such a separate computer-readable storage medium may include a disk, tape, DVD / CD-ROM drive, memory card, or other similar computer-readable medium (not shown). In some example embodiments, the software components may be loaded into the memory 240 via one of the various interfaces 260 rather than via a computer-readable storage medium.

[0072] The processor 220 may be configured to execute instructions of a computer program by performing arithmetic, logical, and input / output operations of the system. The instructions may be provided to the processor 220 by the memory 240.

[0073] The various interfaces 260 may include components that interface the processor 220 with the antenna 265, or other input / output components. As will be appreciated, the various interfaces 260 and the programs stored in the memory 240 for addressing the specific functions of the gNB 102 will vary depending on the implementation of the gNB 102.

[0074] Interface 260 may also include one or more user input devices (eg, keyboard, keypad, mouse, etc.) and user output devices (eg, display, speaker, etc.).

[0075] Although not specifically discussed in this article, Figure 2 The illustrated configuration may be used to implement the TRPs 102a, 102b, 102c, other radio access and backhaul network elements and / or devices, etc. In this regard, for example, the memory 240 may store an operating system and any other routines / modules / applications for providing the functionality of the TRPs, etc. to be executed by the processor 220 (e.g., the functionality of these elements, methods according to example embodiments, etc.).

[0076] Figure 3 FIG. 1 is a block diagram of a user equipment (UE) 106a according to an example embodiment. It should be understood that other UEs 106b, 106c, 106d have the same structure. In the example embodiment, UE 106a is a terminal user using Figure 1 A device that communicates with a network 10. Examples of UE include cellular phones, smartphones, tablets, computers, laptops, vehicles, in-vehicle devices, other Internet of Things (IoT) devices, etc.

[0077] As shown, UE 106a includes: a memory 340; a processor 320 connected to the memory 340; various interfaces 360 connected to the processor 320; and one or more antennas or antenna panels 365 connected to the various interfaces 360. The various interfaces 360 and antennas 365 may constitute a transceiver for transmitting / receiving data to / from gNB 102 or to / from multiple TRPs 102a, 102b, 102c, etc. via multiple wireless beams. As will be appreciated, depending on the implementation of UE 106a, UE 106a may include more than Figure 3 Many more components are shown. However, it is not necessary to show all of these typically conventional components in order to disclose an illustrative example embodiment.

[0078] The memory 340 may be a computer-readable storage medium, which typically includes a random access memory (RAM), a read-only memory (ROM), and / or a permanent mass storage device, such as a disk drive. The memory 340 also stores an operating system and any other routines / modules / applications for providing the functions of the UE 106a to be executed by the processor 320 (e.g., the functions of the UE, the methods according to the example embodiments, etc.). These software components may also be loaded into the memory 340 from a separate computer-readable storage medium using a drive mechanism (not shown). Such a separate computer-readable storage medium may include a disk, a tape, a DVD / CD-ROM drive, a memory card, or other similar computer-readable media (not shown). In some example embodiments, the software components may be loaded into the memory 340 via one of the various interfaces 360 rather than via a computer-readable storage medium.

[0079] The processor 320 may be configured to execute instructions of a computer program by performing arithmetic, logical, and input / output operations of the system. The instructions may be provided to the processor 320 by the memory 340.

[0080] The various interfaces 360 may include components that interface the processor 320 with an antenna 365, or other input / output components. As will be appreciated, the various interfaces 360 and the programs stored in the memory 340 for addressing the specific functions of the UE 106a will vary depending on the implementation of the UE 106b.

[0081] Interface 360 ​​may also include one or more user input devices (eg, keyboard, keypad, mouse, etc.) and user output devices (eg, display, speaker, etc.).

[0082] General method - mapping:

[0083] In an example embodiment, the first set of information (overall group size and member ID) can be used by Rx UE 106b to determine PSFCH resources. In an example embodiment, the second set of information is used to update (modify) the group size (e.g., actual group size) of the active group members and the member IDs of these active members. Herein, the member ID of each Rx UE (e.g., 106b, 106c) in the first set of information and the second set of information should not change. After obtaining the updated second set of information, the transmission on the ongoing HARQ process is adapted accordingly.

[0084] General method - enhanced HARQ:

[0085] Some example embodiments address the possible impact of the accuracy and timing of group information updates on HARQ operation and performance of SL multicast.

[0086] In an example embodiment, a Tx UE behavior is proposed to enhance HARQ with dedicated feedback for SL multicast that adapts to the accuracy and timing of updated group information as follows:

[0087] 1. In an example embodiment, the SL multicast Tx UE is updated with group information including members that are believed to be currently present in the vicinity of the Tx UE. In an example embodiment, this update may be periodic or event triggered.

[0088] 2. In an example embodiment, the Tx UE is configured to adapt the current HARQ process based on the latest updated group information received during the current HARQ process using at least one of the following options (see A.-D. below), depending on the changes in the group configuration and the QoS requirements of the ongoing data.

[0089] A. In an example embodiment, the processor 320 of the Tx UE 106a continues the current HARQ process and ignores the update. In an example embodiment, this option is further applicable to the case where the group update indicates no change or group reduction, which has no effect on the current HARQ process (including the case where the Tx UE terminates the HARQ process if a NACK is received from some member(s) in the previous group that is not currently in the updated group, and an ACK is received from the remaining members of the updated group). The latter refers to the case where some packet loss within a certain time limit is tolerable for multicast (such as in a voice group call). Otherwise, one of the following options may be considered.

[0090] B. In an exemplary embodiment, if there are more group members in the updated group, the processor 320 of the Tx UE 106a continues the current HARQ process using the self-decoded redundant version of the transport block (TB), and extends the HARQ process by the determined number of HARQ retransmissions based on the determined maximum number of HARQ retransmissions. In an exemplary embodiment, this allows new group members and existing group members that have not received the TB to continue the current HARQ process without restarting, and thus the existing group members do not lose the combining gain of using the redundant version of the previously received TB.

[0091] C. In an example embodiment, the processor 320 of the Tx UE 106a continues to perform the current HARQ process for existing members that remain in the updated group and have not received the TB (from which NACK was previously received), and initiates a new HARQ process for the current TB, and the new HARQ process is addressed to the new UE(s) added to the group.

[0092] C1 In an example embodiment, a 1-bit indication may be introduced in the SCI to indicate that the new HARQ process is for an existing TB so that existing members of the group (retained from a previous update) may ignore the new HARQ process.

[0093] D. In an example embodiment, the processor 320 of the Tx UE 106a uses NDI to restart the current HARQ process or terminate the current HARQ process and initiate a new HARQ process for the current TB or a new TB including data of the current TB, for example, when the HARQ process has just started the first transmission and HARQ feedback (ACK / NACK / DRX) has not been received, or ACK has not been received, or the number of received NACKs is high enough.

[0094] 3. In an example embodiment, upon receiving / detecting HARQ DTX from a member for a certain number of times during the current HARQ process, the Tx UE may consider that the member is not nearby. In an example embodiment, the Tx UE may be configured to perform at least one of the following options (see a and b below).

[0095] a. In an example embodiment, the Tx UE ignores this member in the remainder of the current HARQ process.

[0096] b. In an exemplary embodiment, the access layer at the Tx UE responsible for controlling and executing the current HARQ process reports the member to the upper layer (application layer) at the Tx UE. This means, for example, that the processor of the Tx UE 106a records the identity of the member within the upper layer of the Tx UE 106a.

[0097] Specific example embodiments:

[0098] Figure 4 A method of initiating a communication process according to an example embodiment is illustrated. In an example embodiment, the steps of the method are performed by the processor 320 of the Tx UE 106a.

[0099] In an exemplary embodiment, as shown in step S400, the processor 320 of the Tx UE 106a receives first group information for a user group, the first user group information including information for mapping a side link channel resource for each user equipment member of the user group for the user group to perform a first multicast communication via a first side link. In an exemplary embodiment, the Tx UE 106a is a member of the user group.

[0100] In an example embodiment, as shown in step S402, the processor 320 of the Tx UE 106a receives a second set of information for transmitting data during the first multicast communication. In an example embodiment, the second set of information includes updated information of the first set of information specific to the Tx UE 106a.

[0101] In an exemplary embodiment, as shown at S404, the processor 320 of the Tx UE 106a initiates a transmission process based on the first group information to transmit a first data block to a user group for multicast communication through a side link.

[0102] In an example embodiment, as shown at S406 , the processor 320 of the Tx UE 106 a adapts a transmission process of the first data block based on the second set of information.

[0103] Figure 5 A signaling diagram according to an example embodiment is illustrated. In an example embodiment, as shown in step S500, the processor 320 of the transmitting UE (e.g., Tx UE 106a) uses the stored group information to initiate a first side link transmission process for transmitting a transport block (TB) or data block for a multicast communication involving user equipment members of a user group (e.g., UE 106b, 106c, 106d). In an example embodiment, the Tx UE 106a is a member of the user group. In an example embodiment, the transmission process is a HARQ transmission process. In an example embodiment, as shown in step S502, the processor 320 of the Tx UE 106a transmits a HARQ TB to multiple receiving UEs (e.g., Rx UE 106b), wherein the Rx UE 106b is a member of the user group for the multicast communication. In an example embodiment, steps S500 and S502 correspond to Figure 4 Step S404.

[0104] In an exemplary embodiment, as shown in step S504, the processor 320 of the Tx UE 106a receives an update (updated information) of the group information (second group information) from an upper layer (e.g., an application layer) at the Tx UE 106a. For example, the update may be based on information exchange on the application layer between members of the user group. In an exemplary embodiment, as shown in step S506, the processor 320 of the Tx UE 106a receives feedback information (HARQ ACK / NACK / DRX) from the members of the group on a dedicated PSFCH. In an exemplary embodiment, the feedback information is HARQ feedback information. In an exemplary embodiment, steps S504 and S506 correspond to Figure 4 Step S402.

[0105] In an example embodiment, step S504 may occur before initiating the first side link transmission process (step S500), or step S504 may occur after initiation of the first side link transmission process (e.g., once step S500 is ongoing), wherein step S504 may, for example, occur while step S502 (transmission of the first side link transmission process) is occurring or partially occurring.

[0106] In an exemplary embodiment, as shown in step S508, the processor 320 of the Tx UE 106a determines whether to continue the current transmission process based on the updated information and based on the feedback information. In an exemplary embodiment, as shown in step S510, the processor 320 of the Tx UE 106a and the processor 320 of the Rx UE 106b jointly perform one of the options (described above) based on the determination in step S508. This step corresponds to the above-mentioned "Option 2C".

[0107] In an example embodiment, as shown in step S512, the processor 320 of the Tx UE 106a initiates a second sidelink transmission process for transmitting a transport block. In an example embodiment, the second transmission process is for a changed plurality of members of the user group. In an example embodiment, the second transmission process is initiated to transmit the same transport block included in the first transmission process. In an example embodiment, the second transmission process includes a flag (indicator) to the user group, which indicates to the user group (e.g., existing and / or changed members of the user group) that the transport block is the same transport block included in the first sidelink transmission process. In an example embodiment, step S512 corresponds to Figure 4 Step S406.

[0108] In an example embodiment, as shown in step S514, the processor 320 of the Tx UE 106a transmits the second side link transmission process to the Rx UE 106b. In an example embodiment, as shown in step S516, as an alternative to step S514, the processor 320 of the Tx UE 106a sends the second side link transmission process with a flag (indicator), as described above.

[0109] In an example embodiment, as shown in step S518, once the processor 320 of the existing member receives the flag (indicator), the processor 320 of the existing member of the user group including the processor 320 of the Rx UE 106b skips the second sidelink transmission process.

[0110] In an exemplary embodiment, as shown in step S520, the processors 320 of the Rx UE 106b and other existing members of the user group transmit feedback information (ACK / NACK / DTX) to the Tx UE 106a. In an exemplary embodiment, as shown in step S522, the added (new) member of the user group sends feedback information to the Tx UE 106a.

[0111] In an exemplary embodiment, as shown in step S524, the processor 320 of the Tx UE 106a reports the group information to the upper layer at the Tx UE based on the received HARQ feedback information. In an exemplary embodiment, for example, in this step, the processor 320 of the Tx UE 106a reports to the upper layer (application layer) at the Tx UE the Rx UE with one or more consecutive DTX HARQ feedback information as detected by the Tx UE. This information can be used by the upper layer for group management. In an exemplary embodiment, the Tx UE is configured to ignore the Rx UE with one or more consecutive DTX HARQ feedback information for the remainder of the transmission process.

[0112] In an example embodiment, as shown in step S508, the processor 320 of the Tx UE 106a

[0113] Although the terms first, second, etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, the first element can be referred to as the second element, and similarly, the second element can be referred to as the first element. As used herein, the term "and / or" includes any and all combinations of one or more related listed items.

[0114] When an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element or there may be intervening elements. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent to" versus "directly adjacent to," etc.).

[0115] The terms used herein are for the purpose of describing specific embodiments only and are not intended to be limiting. As used herein, the singular forms "a", "an", and "the" also include the plural forms, unless the context clearly indicates otherwise. It should be further understood that the terms "comprises", "comprising", "includes", and / or "including" when used herein specify the presence of the features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groups thereof.

[0116] It should also be noted that in some alternative implementations, the functions / actions may occur in a different order than that described in the figures. For example, two figures shown in succession may actually be performed substantially simultaneously, or may sometimes be performed in reverse order, depending on the functions / actions involved.

[0117] Specific details are provided in the following description to provide a thorough understanding of the example embodiments. However, one of ordinary skill in the art will appreciate that the example embodiments may be practiced without these specific details. For example, the system may be shown in a block diagram to avoid obscuring the example embodiments with unnecessary details. In other cases, well-known processes, structures, and techniques may be shown without unnecessary details to avoid obscuring the example embodiments.

[0118] As discussed herein, the illustrative embodiments will be described with reference to acts and symbolic representations of operations (e.g., in the form of flow charts, flow diagrams, data flow diagrams, structure diagrams, block diagrams, etc.), which may be implemented as program modules or functional processes, including routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types, and may be implemented using existing hardware at, for example, existing user equipment, base stations, evolved Node Bs (eNBs), remote radio heads (RRHs), 5G base stations (gNBs), femto base stations, network controllers, computers, etc. Such existing hardware may be processing or control circuitry such as, but not limited to, one or more processors, one or more central processing units (CPUs), one or more controllers, one or more arithmetic logic units (ALUs), one or more digital signal processors (DSPs), one or more microcomputers, one or more field programmable gate arrays (FPGAs), one or more systems on chips (SoCs), one or more programmable logic units (PLUs), one or more microprocessors, one or more application specific integrated circuits (ASICs), or one or more other devices capable of responding to and executing instructions in a defined manner.

[0119] Although a flow chart may describe operations as a sequential process, many operations may be performed in parallel, concurrently, or simultaneously. In addition, the order of the operations may be rearranged. A process may terminate when its operations are completed, but may also have additional steps not included in the figure. A process may correspond to a method, function, process, subroutine, subprogram, etc. When a process corresponds to a function, its termination may correspond to the function returning to the calling function or main function.

[0120] As disclosed herein, the term "storage medium", "computer-readable storage medium", or "non-transitory computer-readable storage medium" may refer to one or more devices for storing data, including read-only memory (ROM), random access memory (RAM), magnetic RAM, core memory, magnetic disk storage media, optical storage media, flash memory devices, and / or other tangible machine-readable media for storing information. The term "computer-readable medium" may include, but is not limited to, portable or fixed storage devices, optical storage devices, and various other media capable of storing, containing, or carrying (multiple) instructions and / or data.

[0121] In addition, the example embodiments can be implemented by hardware, software, firmware, middleware, microcode, hardware description language or any combination thereof. When implemented with software, firmware, middleware or microcode, the program code or code segment for performing the necessary tasks can be stored in a machine or computer readable medium (such as a computer readable storage medium). When implemented with software, one or more processors will perform the necessary tasks. For example, as described above, according to one or more example embodiments, at least one memory may include or store computer program code, and at least one memory and computer program code may be configured to cause a network element or network device to perform necessary tasks together with at least one processor. In addition, the processor, memory and example algorithm encoded as computer program code are used as parts for providing or causing the execution of the operation discussed herein.

[0122] The code segment of computer program code can represent any combination of process, function, subprogram, program, routine, subroutine, module, software package, class, or instruction, data structure, or program statement. Code segment can be coupled to another code segment or hardware circuit by transmitting and / or receiving information, data, independent variable, parameter, or memory content. Information, independent variable, parameter, data etc. can be transmitted, forwarded, or transmitted via any suitable technology, including memory sharing, message passing, token passing, network transmission etc.

[0123] As used herein, the terms "including" and / or "having" are defined as comprising (i.e., open language). The term "coupled," as used herein, is defined as connected, although not necessarily directly and not necessarily mechanically. Terms derived from the word "indicating" (e.g., "indicates" and "indication") are intended to cover all of the various techniques that can be used to transmit or reference the indicated object / information. Some, but not all, examples of techniques that can be used to transmit or reference the indicated object / information include transmission of the indicated object / information, transmission of an identifier of the indicated object / information, transmission of information used to generate the indicated object / information, transmission of a segment or portion of the indicated object / information, transmission of some derivative of the indicated object / information, and transmission of some symbol representing the indicated object / information.

[0124] According to example embodiments, user equipment, base stations, eNBs, RRHs, gNBs, femto base stations, network controllers, computers, etc. may be (or include) hardware, firmware, hardware executing software, or any combination thereof. Such hardware may include processing or control circuit systems, such as, but not limited to, one or more processors, one or more CPUs, one or more controllers, one or more ALUs, one or more DSPs, one or more microcomputers, one or more FPGAs, one or more SoCs, one or more PLUs, one or more microprocessors, one or more ASICs, or one or more other devices capable of responding to and executing instructions in a defined manner.

[0125] The benefits, other advantages, and solutions to problems have been described above with respect to specific embodiments of the present disclosure. However, the benefits, advantages, solutions to problems, and any element(s) that may cause or produce such benefits, advantages, or solutions, or cause such benefits, advantages, or solutions to become more apparent, shall not be construed as key, necessary, or essential features or elements of any or all of the claims.

Claims

1. A method for communication, include: receiving, by at least one first processor of a first user equipment (UE), first group information for a user group having user equipment members, the first group information comprising information for mapping a sidelink channel resource for each of the user equipment members for the user group to perform multicast communication via a sidelink, the first UE being a user equipment member of the user group; receiving, by the at least one first processor, a second set of information for transmitting data within the multicast communication, the second set of information comprising updated information of the first set of information specific to the first UE; Initiating, by the at least one first processor, a first transmission process based on the first group information to transmit a first data block to the user group for the multicast communication through the side link; as well as adapting, by the at least one first processor, the first transmission process of the first data block based on the second set of information, Wherein adapting the first transmission process based on the second set of information comprises: initiating a second transmission process based on the second set of information to transmit a second data block to the user group used for the multicast communication through the side link, wherein the second transmission process comprises an indicator, and the indicator indicates to the user group that the first data block in the first transmission process and the second data block in the second transmission process are the same data block.

2. The method of claim 1, wherein the first transmission process is a hybrid automatic repeat request (HARQ) process through the sidelink.

3. The method of claim 1, wherein the sidelink channel resource is a physical sidelink feedback channel (PSFCH).

4. The method of claim 1 , wherein the receiving of the second set of information occurs during one of: Before initiating the first transmission process, or After said initiation of said first transmission process and during a time period while said first transmission process is ongoing.

5. The method according to claim 1, further comprising: include: receiving first feedback information from the user group, The adaptation of the first transmission process includes: determining whether to continue the first transmission process based on the second set of information and the first feedback information.

6. The method according to claim 5, wherein the first feedback information is HARQ feedback information, and the HARQ feedback information includes one of acknowledgment, negative acknowledgment, or discontinuous transmission (DTX) information.

7. The method according to claim 5, further comprising: include: Second feedback information is received from at least one first user equipment among the user equipment members of the user group, which has received the first data block of the first transmission process, wherein the second feedback information indicates that the at least one first user equipment will ignore the second transmission process.

8. The method according to any one of claims 1 to 7, further comprising: include: After the initiation of the first transmission process, receiving DTX feedback information from at least one first user equipment among the user equipment members; Initiating, at the first UE, reporting of the identity of the at least one first user equipment from the access layer to the application layer; and / or During the remainder of the first transmission process, the at least one first user equipment is ignored.

9. A first network node, include: a memory containing computer-readable instructions; as well as At least one first processor is configured to read and execute the computer readable instructions so as to receiving first group information for a user group having user equipment members, the first group information comprising information for mapping a side link channel resource for each of the user equipment members for the user group to perform multicast communication via a side link, the first network node being a user equipment member of the user group, receiving a second set of information for transmitting data within the multicast communication, the second set of information comprising updated information of the first set of information specific to the first network node, initiating a first transmission process based on the first set of information to transmit a first data block to the user group for the multicast communication via the side link, and adapting the first transmission process of the first data block based on the second set of information, Wherein adapting the first transmission process based on the second set of information comprises: initiating a second transmission process based on the second set of information to transmit a second data block to the user group used for the multicast communication through the side link, wherein the second transmission process comprises an indicator, and the indicator indicates to the user group that the first data block in the first transmission process and the second data block in the second transmission process are the same data block.

10. The first network node of claim 9, wherein the first transmission process is a hybrid automatic repeat request (HARQ) process over the sidelink.

11. The first network node of claim 9, wherein the sidelink channel resource is a Physical Sidelink Feedback Channel (PSFCH).

12. The first network node of claim 9, wherein the at least one first processor is configured to receive the second set of information during one of: Before initiating the first transmission process, or After said initiation of said first transmission process and during a time period while said first transmission process is ongoing.

13. The first network node according to claim 9, wherein the at least one first processor is further configured to: receiving first feedback information from the user group, wherein the adaptation of the first transmission process include: Determine whether to continue the first transmission process based on the second set of information and the first feedback information.

14. The first network node according to claim 13, wherein the first feedback information is HARQ feedback information, and the HARQ feedback information includes one of acknowledgment, negative acknowledgment, or discontinuous transmission (DTX) information.

15. The first network node according to claim 13, wherein the at least one first processor is further configured to: Second feedback information is received from at least one first user equipment among the user equipment members of the user group, which has received the first data block of the first transmission process, wherein the second feedback information indicates that the at least one first user equipment will ignore the second transmission process.

16. The first network node according to any one of claims 9 to 15, wherein the at least one first processor is further configured to: After the initiation of the first transmission process, receiving DTX feedback information from at least one first user equipment among the user equipment members, Initiating, at the first UE, a report of the identity of the at least one first user equipment from the access layer to the application layer, and / or During the remainder of the first transmission process, the at least one first user equipment is ignored.

17. A computer-readable storage medium comprising program instructions stored thereon for executing the method according to any one of claims 1 to 8.

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