Wireless communication device and method for data packet discarding

Abstract

The invention discloses a data packet discarding method executed by first wireless communication equipment, which comprises the following steps that: the first wireless communication equipment sends a protocol data unit (PDU) to second wireless communication equipment, the PDU header of the PDU contains PDU set related information, and the PDU header of the PDU contains PDU set related information; the PDU set related information is used for the second wireless communication equipment to identify which PDU set the PDU belongs to and the dependent PDU set; detecting, by the first wireless communication device, a status report based on a PDU set sent by the second wireless communication device, the status report based on the PDU set indicating that the dependent PDU set has been lost or unsuccessfully transmitted when the PDU in the dependent PDU set is lost or unsuccessfully transmitted; when the status report based on the PDU set is detected, a service data unit (SDU) belonging to a PDU set associated with the dependent PDU set is discarded by the first wireless communication device.

Description

Technical Field

[0001] The present application relates to the field of wireless communication systems, and more specifically, to a wireless communication device and a wireless communication method for performing packet discarding in a 5G NR (new wireless) communication system. More specifically, the present application discusses the relevant content of the new work item "XR Enhancements for NR" in Release 18, which may be led by RAN2. The purpose of the present application is to support the associated processing of traffic in a 5G wireless communication system (NR, new wireless) to support extended reality (XR, eXtended Reality) services, including representative forms such as augmented reality (AR), virtual reality (VR) or mixed reality (MR). In addition, the topic of XR-awareness in RAN is also involved. Information related to the specific XR service PDU set provided by 5GC (for example, PDU set sequence number, PDU size, PDU set dependency, etc.) may also be discussed in this application. Background Art

[0002] 5G wireless communication systems are designed to provide enhanced mobile broadband (eMBB), ultra-reliable low latency communication (URLLC), and massive machine type communication (mMTC) services. For 5G or NR, support for eMBB, URLLC, and mMTC was first introduced in Release 15 and enhanced in Release 16 and Release 17. Extended Reality (XR) is a general term covering augmented reality (AR), mixed reality (MR), and virtual reality (VR). XR applications generally require high throughput and low latency, and cloud gaming is another application with the same requirements. XR and cloud gaming are important applications supported by 5G.

[0003] XR services are characterized by their special real-time, high data rate and low latency traffic. Especially for video streams, different frames / video slice packets have different characteristics. XR service flows have some special characteristics that should be considered when 5G supports XR services.

[0004] In the prior art, for XR services, video is one of the typical traffic types of XR services. We first analyze the characteristics of video. According to the description of "IP Video Encoding Explained", when encoding a video, the video frames are arranged in the order of "Group of Picture (GOP)". A single GOP consists of one or more of the following frame types in order (see Figure 1 ):

[0005] Intra-coded frame (I-frame): A frame that is independently coded (it is coded without reference to any other frame). The first frame in a GOP is always an I-frame. I-frames have the largest amount of data (require the most bits) and can be decoded at the receiving end without relying on the data of any other frame.

[0006] (Forward) Predictive Coding Frame (P-frame): A frame that is coded based on the motion changes of the most recent I-frame or P-frame. The amount of data in a P-frame is smaller than that of an I-frame.

[0007] Bidirectionally predictive coded frames (B frames): Frames that are coded based on the most recent I or P frame, the next I or P frame, or a combination of both. B frames require the fewest bits, but video quality may suffer if too many B frames are used. Unlike I and P frames, B frames are not used as reference frames for other frames.

[0008] In a GOP, the first frame is always an I-frame, which is independently coded using intra-frame coding, as described above. P-frames are coded based on the motion differences of the previous I-frame or P-frame. B-frames can be bidirectionally predicted, using the most recent I-frame or P-frame, the next I-frame or P-frame, or a combination of both (see Figure 2 ).

[0009] Due to the nature of inter-frame coding, coding or transmission related errors may affect the perceived quality of the video to different degrees, depending on the type of frames affected in the GOP (see Figure 3 ). If an I-frame is corrupted during encoding, or due to packet loss during transmission, the error will propagate to all remaining B- and P-frames in the GOP, causing visible distortion that may last for several seconds. If an error occurs in a P-frame, the error will propagate to all remaining B- and P-frames. If only a single B-frame is affected, the error only affects that frame (usually lasting 15-30 milliseconds), and the viewer may not even notice.

[0010] From the description of the IP video structure above, it can be seen that there are dependencies between the GOP elements (i.e., I-frames, P-frames, and B-frames) in the video frame, which should be considered during transmission. The I-frame is the most important part and must be transmitted successfully, otherwise the subsequent P-frames and B-frames will not be encoded correctly. In this case, all P-frames and B-frames associated with this I-frame will be discarded.

[0011] In addition, from the definition of PDU set, one PDU set corresponds to one I frame / P frame / B frame in XR video. Therefore, the dependency of PDU set corresponds to the dependency of I frame / P frame / B frame in XR service. As mentioned above, if an I frame is received incorrectly, the subsequent P frame / B frame associated with the I frame will be discarded. Therefore, for RAN, when an IPDU set is not successfully received, all related P PDU sets and B PDU sets may need to be discarded. Similarly, if an IPDU set is successfully received, but a certain P PDU set is not successfully received, then its related B PDU set may also need to be discarded. In other words, in RAN, the PDU set should be processed as a whole.

[0012] Therefore, a wireless communication device and a wireless communication method are needed to discuss an XR service-specific packet discard mechanism in the RAN. Summary of the invention

[0013] The purpose of this application is to propose a wireless communication device and method for data packet discarding, and to discuss how to handle data packet discarding in RAN based on XRPDU set related information.

[0014] In a first aspect of the present application, a data packet discarding method is performed by a first wireless communication device, comprising: the first wireless communication device sends a protocol data unit (PDU) to a second wireless communication device, wherein the PDU header of the PDU contains PDU set related information, and the PDU set related information is used by the second wireless communication device to identify which PDU set the PDU belongs to and the dependent PDU set; the first wireless communication device detects a PDU set-based status report sent by the second wireless communication device, and when a PDU in the dependent PDU set is lost or unsuccessfully transmitted, the PDU set-based status report indicates that the dependent PDU set has been lost or unsuccessfully transmitted; when the PDU set-based status report is detected, the first wireless communication device discards a service data unit (SDU) belonging to the PDU set associated with the dependent PDU set; wherein the data packet discarding method is performed by a packet data convergence protocol (PDCP) entity or a radio link control (RLC) entity of the first wireless communication device.

[0015] In a second aspect of the present application, a data packet discarding method is performed by a second wireless communication device, comprising: the second wireless communication device detects a protocol data unit (PDU) sent by a first wireless communication device, the PDU header of the PDU containing the PDU set related information, wherein the PDU set related information is used by the second wireless communication device to identify which PDU set the PDU belongs to, and the dependent PDU set; the second wireless communication device sends a PDU set-based status report to the first wireless communication device when the dependent PDU set is lost or unsuccessfully transmitted, wherein the PDU set-based status report indicates that the dependent PDU set is lost or unsuccessfully transmitted; when the PDU set-based status report is detected, the first wireless communication device is controlled to discard a service data unit (SDU) belonging to the PDU set associated with the dependent PDU set; wherein the data packet discarding method is performed by a packet data convergence protocol (PDCP) entity or a radio link control (RLC) entity of the second wireless communication device.

[0016] In a third aspect of the present application, a first wireless communication device includes a memory, a transceiver, and a processor connected to the memory and the transceiver. The processor is configured to execute the above method.

[0017] In a fourth aspect of the present application, a second wireless communication device includes a memory, a transceiver, and a processor connected to the memory and the transceiver, wherein the processor is configured to execute the above method.

[0018] In a fifth aspect of the present application, a non-transitory machine-readable storage medium stores instructions thereon, and when a computer executes the instructions, the instructions cause the computer to execute the above method.

[0019] In a sixth aspect of the present application, a chip includes a processor configured to call and run a computer program stored in a memory so that a device equipped with the chip executes the above method.

[0020] In a seventh aspect of the present application, a computer-readable storage medium stores a computer program, wherein the computer program enables a computer to execute the above method.

[0021] In an eighth aspect of the present application, a computer program product comprises a computer program, wherein the computer program enables a computer to execute the above method.

[0022] In a ninth aspect of the present application, a computer program is provided, wherein the computer program enables a computer to execute the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or related technologies, the following briefly introduces the drawings to be described in the embodiments. Obviously, the drawings are only some embodiments of the present application, and ordinary technicians in this field can obtain other drawings based on these drawings without paying any price.

[0024] Figure 1 is a schematic diagram of an exemplary GOP structure.

[0025] Figure 2 It is a schematic diagram of the coding dependency between P frames and B frames.

[0026] Figure 3 It is a schematic diagram of error propagation in GOP.

[0027] Figure 4 It is a block diagram of a first wireless communication device and a second wireless communication device in a communication network system according to an embodiment of the present application.

[0028] Figure 5It is a flowchart of a data packet discarding method executed by a first wireless communication device according to an embodiment of the present application.

[0029] Figure 6 It is a flowchart of a data packet discarding method executed by a second wireless communication device according to an embodiment of the present application.

[0030] Figure 7 This is an example schematic diagram of mapping the associated PDU sets of a GOP to the same DRB according to an embodiment of the present application.

[0031] Figure 8 This is a schematic diagram of an example of a PDCP status report based on a PDCP PDU set according to an embodiment of the present application.

[0032] Fig. 9 This is an example schematic diagram of mapping the associated PDU set of a GOP to different DRBs according to an embodiment of the present application.

[0033] Fig.10 It is an example schematic diagram of a radio resource control (RRC) reconfiguration process according to an embodiment of the present application.

[0034] Fig.11 This is a schematic diagram of an example of a PDCP status report based on a PDCP PDU set according to an embodiment of the present application.

[0035] Fig.12 This is an example schematic diagram of mapping the associated PDU sets of a GOP to the same DRB according to an embodiment of the present application.

[0036] Fig.13 is a block diagram of a first wireless communication device according to an embodiment of the present application.

[0037] Fig.14 is a block diagram of a second wireless communication device according to an embodiment of the present application.

[0038] Fig.15 is a block diagram of a wireless communication system according to an embodiment of the present application. DETAILED DESCRIPTION

[0039] The technical content, structural features, objectives and effects of the present application are described in detail below in conjunction with the accompanying drawings. Specifically, the terms in the embodiments of the present application are only used to describe the purpose of specific embodiments, and are not intended to limit the present application.

[0040] Figure 4It is described that in some embodiments, a first wireless communication device 10 and a second wireless communication device 20 for communication in a communication network system 40 are provided, and the communication network system 40 includes the first wireless communication device 10 and the second wireless communication device 20. The first wireless communication device 10 may include a memory 12, a transceiver 13 and a processor 11, wherein the processor 11 is coupled to the memory 12 and the transceiver 13. The second wireless communication device 20 may include a memory 22, a transceiver 23 and a processor 21, wherein the processor 21 is coupled to the memory 22 and the transceiver 23. The processor 11 or 21 may be configured to implement the functions, processes and / or methods described herein. The layers of the wireless interface protocol may be implemented in the processor 11 or 21. The memory 12 or 22 is operatively coupled to the processor 11 or 21, and stores a variety of information to operate the processor 11 or 21. The transceiver 13 or 23 is operatively coupled to the processor 11 or 21, and the transceiver 13 or 23 is responsible for sending and / or receiving wireless signals.

[0041] The processor 11 or 21 may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits and / or data processing devices. The memory 12 or 22 may include a read-only memory (ROM), a random access memory (RAM), a flash memory, a memory card, a storage medium and / or other storage devices. The transceiver 13 or 23 may include a baseband circuit for processing radio frequency signals. When the embodiment is implemented in software, the techniques described herein may be implemented by modules (e.g., procedures, functions, etc.) that perform the functions described herein. These modules may be stored in the memory 12 or 22 and executed by the processor 11 or 21. The memory 12 or 22 may be implemented inside the processor 11 or 21, or outside the processor 11 or 21, in which case it may be communicatively coupled to the processor 11 or 21 in various known ways.

[0042] In some embodiments, the transceiver 13 is configured to send a protocol data unit (PDU) to the second wireless communication device 20, wherein the PDU header of the PDU contains PDU set related information, and the PDU set related information is used by the second wireless communication device 20 to identify which PDU set the PDU belongs to and the dependent PDU set. The processor 11 is configured to detect a PDU set-based status report sent by the second wireless communication device 20, and when a PDU in the dependent PDU set is lost or unsuccessfully transmitted, the PDU set-based status report indicates that the dependent PDU set has been lost or unsuccessfully transmitted. The processor 11 is also configured to, when the PDU set-based status report is detected, discard the service data unit (SDU) belonging to the PDU set associated with the dependent PDU set by the first wireless communication device 10; wherein the data packet discarding method is performed by a packet data convergence protocol (PDCP) entity or a radio link control (RLC) entity of the first wireless communication device 10. This method can save wireless transmission resources for XR services.

[0043] In some embodiments, the processor 21 is configured to detect a protocol data unit (PDU) sent by the first wireless communication device 10, the PDU header of the PDU containing the PDU set related information, wherein the PDU set related information is used by the second wireless communication device 20 to identify which PDU set the PDU belongs to, and the dependent PDU set. The transceiver 23 is configured to send a PDU set-based status report to the first wireless communication device 10 when the dependent PDU set is lost or unsuccessfully transmitted, wherein the PDU set-based status report indicates that the dependent PDU set is lost or unsuccessfully transmitted. The processor 21 is also configured to control the first wireless communication device 10 to discard the service data unit (SDU) belonging to the PDU set associated with the dependent PDU set when the PDU set-based status report is detected; wherein the data packet discarding method is performed by the packet data convergence protocol (PDCP) entity or the radio link control (RLC) entity of the second wireless communication device 20. This method can save wireless transmission resources for XR services.

[0044] Figure 5The invention discloses a method for discarding a data packet performed by a first wireless communication device according to an embodiment of the present application. In some embodiments, the method 500 includes: step 502, the first wireless communication device sends a protocol data unit (PDU), wherein the PDU header of the PDU contains PDU set related information, and the PDU set related information is used by the second wireless communication device to identify which PDU set the PDU belongs to and the dependent PDU set; step 504, the first wireless communication device detects a PDU set-based status report sent by the second wireless communication device, when the PDU in the dependent PDU set is lost or unsuccessfully transmitted, the PDU set-based status report indicates that the dependent PDU set has been lost or unsuccessfully transmitted; step 506, when the PDU set-based status report is detected, the first wireless communication device discards a service data unit (SDU) belonging to the PDU set associated with the dependent PDU set; wherein the method for discarding a data packet is performed by a packet data convergence protocol (PDCP) entity or a radio link control (RLC) entity of the first wireless communication device. This method can save wireless transmission resources for XR services.

[0045] Figure 6The invention discloses a method for discarding a data packet performed by a second wireless communication device according to an embodiment of the present application. In some embodiments, the method 600 includes: step 602, the second wireless communication device detects a protocol data unit (PDU) sent by a first wireless communication device, the PDU header of the PDU containing the PDU set related information, wherein the PDU set related information is used by the second wireless communication device to identify which PDU set the PDU belongs to and the dependent PDU set; step 604, the second wireless communication device sends a PDU set-based status report to the first wireless communication device when the dependent PDU set is lost or unsuccessfully transmitted, wherein the PDU set-based status report indicates that the dependent PDU set is lost or unsuccessfully transmitted; step 606, when the PDU set-based status report is detected, the first wireless communication device is controlled to discard a service data unit (SDU) belonging to the PDU set associated with the dependent PDU set; wherein the method for discarding a data packet is performed by a packet data convergence protocol (PDCP) entity or a radio link control (RLC) entity of the second wireless communication device. This method can save wireless transmission resources for XR services.

[0046] Embodiment 1:

[0047] In this embodiment, the specific packet discarding mechanism applicable to the XR service at the RAN PDCP layer is mainly considered.

[0048] Specifically, when the PDCP entity at the receiving end confirms that the dependent PDCP PDU set has not been successfully transmitted based on the PDU set granularity through the PDCP status report based on the PDU set, the PDCP entity at the transmitting end should discard the PDCP SDU belonging to the PDU set related to the dependent PDCP PDU set. If the corresponding PDCP data PDU has been submitted to the lower layer, the discard operation should be indicated to the lower layer. For example, when the PDCP entity at the receiving end notifies the loss of the IPDU set through the PDCP status report based on the PDU set, the PDCP entity at the transmitting end should discard the PDCP SDU contained in the P PDU set and the B PDU set because these PDU sets are associated with the IPDU set. In other words, the data packets in the P PDU set and the B PDU set are dependent on the data packets in the IPDU set.

[0049] In this embodiment, the associated PDU sets of the XR service are mapped to the same DRB, that is, centralized DRB mapping is adopted. Figure 7is a schematic diagram illustrating an embodiment of the present application, in which all PDU sets of the same GOP are mapped to the same DRB. Figure 7 As shown, all PDU sets of Gop1 are mapped to DRB1, and all PDU sets of Gop2 are mapped to DRB2. (Note: For easier explanation, the following takes the Gop-based model as an example, where one Gop contains IPDU sets, P PDU sets, and B PDU sets.)

[0050] As mentioned above, the dependencies of the PDU set in a Gop are as follows:

[0051] The decoding of the P PDU set depends on the IPDU set. The decoding of the B PDU set depends on the IPDU set and the P PDU set.

[0052] Therefore, it can be inferred that at the transmitting end of the RAN:

[0053] If an IPDU set is lost or unsuccessfully transmitted, its associated P PDU set and B PDU set shall be discarded; if a P PDU set is lost or unsuccessfully transmitted, its associated B PDU set shall be discarded.

[0054] To support packet discard for XR services and implement a packet discard scheme based on PDU sets, the PDCP layer needs to be enhanced as follows:

[0055] 1. Enhance the PDCP data PDU function of DRB. Specifically, it is necessary to add PDU set related information to the PDCP PDU header at the transmitting end so that the PDCP entity at the receiving end can determine whether the dependent PDCP PDU set is not successfully transmitted. When the dependent PDCP PDU set is lost, the PDCP entity at the receiving end can send a PDCP status report to the PDCP entity at the transmitting end.

[0056] The PDU set related information includes at least one of the following:

[0057] PDU Set type: This field indicates whether the type of the corresponding PDU set is an IPDU set, a P PDU set or a B PDU set.

[0058] PDU Set Sequence Number: This field indicates the sequence number of the corresponding PDU set.

[0059] PDU Sequence Number in a PDU Set: This field indicates the sequence number of the corresponding PDU contained in the PDU Set.

[0060] Packet priority in a PDU Set: This field indicates whether the corresponding PDU in a PDU Set has the highest priority.

[0061] PI: This field indicates whether the corresponding PDU in the PDU set is the first data packet, the last data packet, or a data packet located between the first and last data packets.

[0062] Dependent PDU Set Sequence Number: This field indicates the sequence number of the dependent PDU set of the corresponding PDU set.

[0063] 2. Enhancement of PDCP status report. Specifically, a PDCP status report based on a PDU set is introduced. When a dependent PDCP PDU set is lost, the receiving PDCP entity may send a PDCP status report to the transmitting PDCP entity (see Figure 8 ). Figure 8 The present invention is a schematic diagram illustrating an embodiment of the present invention, showing an example of a PDCP status report based on a PDU set. Based on the PDCP status report, the transmitting PDCP entity shall discard the PDCP SDU belonging to the PDU set associated with the dependent PDCP PDU set.

[0064] PDU Set based PDCP Status reporting:

[0065] Send operation:

[0066] For AM DRBs or UM DRBs configured by upper layers to send PDU set based PDCP status reports, the receiving PDCP entity shall trigger a PDCP status report when: the dependent PDCP PDU set is lost; and / or the t-Reordering timer expires. If the PDU set based PDCP status report is triggered, the receiving PDCP entity shall do the following: Set the FMP (First Lost Packet) field to the first unsuccessfully received PDU set sequence number; In the bitmap field: for all PDCP SDUs in the PDU set that were not successfully received (and optionally PDCP SDUs that failed to be decompressed), set to '0'; for all successfully received PDCP SDUs in the PDU set, set to '1'; Submit the PDU set based PDCP status report to the lower layers as the first PDCP PDU for transmission by the transmitting PDCP entity.

[0067] Receive operation:

[0068] For AM DRBs or UM DRBs, when the transmitting PDCP entity receives the PDU set PDCP status report, it should perform the following operations: For each PDU set: If the bit value in the bitmap field is '1', or the value of the dependent PDU set sequence number is less than the value of the FMP field, it is considered to have been successfully transmitted; If the bit value in the bitmap field is '0', it is considered to have been unsuccessfully transmitted; If the PDU set type that was not successfully transmitted is "IPDU set type", the PDCP SDUs of all associated PDU sets are discarded according to the dependent PDU set sequence number.

[0069] Embodiment 2:

[0070] In this embodiment, the specific packet discarding mechanism applicable to the XR service at the RAN PDCP layer is mainly considered.

[0071] Specifically, when the receiving-end PDCP entity confirms through a PDU set-based PDCP status report that a dependent PDCP PDU set has not been successfully transmitted, the transmitting-end PDCP entity shall discard the PDCP SDUs belonging to the PDU set associated with the dependent PDCP PDU set. If the corresponding PDCP data PDU has been submitted to the lower layer, the discard operation shall be indicated to the lower layer. For example, when the receiving-end PDCP entity notifies through a PDU set-based PDCP status report that an IPDU set is lost, the transmitting-end PDCP entity shall discard the PDCP SDUs contained in the P PDU set and the B PDU set because these PDU sets are associated with the IPDU set. In other words, the data packets in the P PDU set and the B PDU set depend on the data packets in the IPDU set.

[0072] In this embodiment, the associated PDU sets of the XR service are mapped to different DRBs, that is, a distributed DRB mapping mechanism is adopted. Fig. 9 FIG. 1 is a schematic diagram illustrating an embodiment of the present application, in which a PDU set of the same GOP is mapped to different DRBs. Fig. 9 As shown: All IPDU sets of Gop1 and Gop2 are mapped to DRB1; all P PDU sets and B PDU sets of Gop1 and Gop2 are mapped to DRB2. (Note: For easier explanation, the following takes the GOP-based model as an example, where one GOP contains IPDU sets, P PDU sets, and B PDU sets.)

[0073] As mentioned above, the dependencies of the PDU sets in a GOP are as follows:

[0074] The decoding of the P PDU set depends on the IPDU set. The decoding of the B PDU set depends on the IPDU set and the P PDU set.

[0075] Therefore, it can be inferred that at the transmitting end of the RAN:

[0076] If the IPDU set in DRB1 is lost or unsuccessfully transmitted, the associated P PDU set and B PDU set in DRB2 shall be discarded. If the P PDU set in DRB2 is lost or unsuccessfully transmitted, the associated B PDU set in DRB2 shall be discarded.

[0077] To support packet discard for XR services and implement a packet discard scheme based on PDU sets, the PDCP layer needs to be enhanced as follows:

[0078] 1. Enhance the PDCP data PDU function of DRB. Specifically, it is necessary to add PDU set related information to the PDCP PDU header at the transmitting end so that the PDCP entity at the receiving end can determine whether the dependent PDCP PDU set is not successfully transmitted. When the dependent PDCP PDU set is lost, the receiving end PDCP entity will send a PDCP status report to the transmitting end PDCP entity.

[0079] The PDU set related information includes at least one of the following:

[0080] PDU Set type: This field indicates whether the type of the corresponding PDU set is an IPDU set, a P PDU set, or a B PDU set.

[0081] PDU Set Sequence Number: This field indicates the sequence number of the corresponding PDU set.

[0082] PDU Sequence Number in a PDU Set: This field indicates the sequence number of the corresponding PDU contained in the PDU Set.

[0083] Packet priority in a PDU Set: This field indicates whether the corresponding PDU in a PDU Set has the highest priority.

[0084] PI: This field indicates whether the corresponding PDU in the PDU set is the first data packet, the last data packet, or a data packet located between the first and last data packets.

[0085] Dependent DRB ID: This field indicates the dependent DRB ID to which the PDU set is allocated. For example, PDU set 2 is allocated to DRB2; the dependent PDU set 1 is allocated to DRB1, so the dependent DRB ID is DRB1.

[0086] Dependent PDU Set Sequence Number: This field indicates the sequence number of the dependent PDU set of the corresponding PDU set.

[0087] (Optional) Dependent DRB IDs may be configured by control plane mechanisms. Fig.10 1 is a schematic diagram illustrating an embodiment of the present application, showing an example of the RRC reconfiguration process. When establishing a DRB, the network may use the RRC reconfiguration process to notify the user equipment (UE) that it relies on the DRB ID (see Fig.10 ).

[0088] RADIOBEARERCONFIG (Radio Bearer Configuration):

[0089] Information element (IE): RadioBearerConfig is used to add, modify and release signaling radio bearers (SRBs) and / or data radio bearers (DRBs). Specifically, this IE carries PDCP parameters and, if applicable, parameters of the SDAP (Service Data Adaptation Protocol) entity for radio bearer configuration.

[0090]

[0091]

[0092] 2. Enhancement of PDCP status report: Specifically, a PDCP status report based on a PDU set is introduced. When the dependent PDCP PDU set is lost, the receiving PDCP entity will send a PDCP status report to the transmitting PDCP entity (see Fig.11 ). Based on the PDCP status report, the transmitting PDCP entity shall notify the associated transmitting PDCP entity according to the "dependent DRB ID" that the dependent PDCP PDU set has been lost. Then, the associated transmitting PDCP entity shall discard the PDCP SDU belonging to the PDU set associated with the dependent PDCP PDU set.

[0093] PDU Set based PDCP Status reporting:

[0094] Send operation:

[0095] For AM DRBs or UM DRBs configured by upper layers to send PDU set based PDCP status reports, the receiving PDCP entity shall trigger a PDCP status report when: the dependent PDCP PDU set is lost; and / or the t-Reordering timer expires.

[0096] If the PDU set-based PDCP status report is triggered, the receiving PDCP entity shall perform the following operations: set the FMP (First Lost Packet) field to the first unsuccessfully received PDU set sequence number; in the bitmap field: for all PDCP SDUs in the PDU set that are not successfully received (and optionally PDCP SDUs that fail to decompress), set it to '0'; for all successfully received PDCP SDUs in the PDU set, set it to '1'; submit the PDU set-based PDCP status report as the first PDCP PDU to the lower layer for transmission by the transmitting PDCP entity.

[0097] Receive operation:

[0098] For AM DRBs or UM DRBs, when the transmitting PDCP entity receives the PDU set PDCP status report, it should perform the following operations: For each PDU set: If the bit value in the bitmap field is '1', or the value of the dependent PDU set sequence number is less than the value of the FMP field, it is considered to have been successfully transmitted; If the bit value in the bitmap field is '0', it is considered to have been unsuccessfully transmitted; If the type of the unsuccessfully transmitted PDU set is "IPDU set type", then according to the "dependent DRBID" and "dependent PDU set sequence number", all PDCP SDUs belonging to the associated DRB are discarded.

[0099] Embodiment 3:

[0100] In this embodiment, the specific packet discarding mechanism of the RAN RLC layer applicable to the XR service is mainly considered.

[0101] Specifically, when the receiving RLC entity confirms through the RLC status report that the dependent RLC PDU set has not been successfully transmitted, the transmitting RLC entity shall discard the RLC SDUs belonging to the PDU set associated with the dependent RLC PDU set. For example: when the receiving RLC entity notifies through the RLC status report that the IPDU set is lost, the transmitting RLC entity shall discard the RLC SDUs contained in the P PDU set and the BPDU set, because the data packets in the P PDU set and the B PDU set depend on the data packets in the IPDU set.

[0102] In this embodiment, the associated PDU sets of the XR service are mapped to the same DRB, that is, a centralized DRB mapping mechanism is adopted. Fig.12 FIG. 1 is a schematic diagram illustrating an embodiment of the present application, showing that all PDU sets of the same GOP are mapped to the same DRB. Fig.12 As shown: All PDU sets of Gop1 are mapped to DRB1; all PDU sets of Gop2 are mapped to DRB2. (Note: For easier explanation, the following is an example of a Gop-based model, where one Gop contains an IPDU set, a P PDU set, and a B PDU set.)

[0103] As mentioned above, the dependencies of the PDU set in a Gop are as follows:

[0104] The decoding of the P PDU set depends on the IPDU set. The decoding of the B PDU set depends on the IPDU set and the P PDU set.

[0105] Therefore, it can be inferred that at the sender of the RA: If an IPDU set is lost or unsuccessfully transmitted, the associated PPDU set and B PDU set should be discarded. If a P PDU set is lost or unsuccessfully transmitted, the associated B PDU set should be discarded.

[0106] To support packet drop for XR services and implement a packet drop scheme based on PDU sets, the RLC layer needs to be enhanced as follows:

[0107] 1. Enhance the RLC data PDU function of DRB: Specifically, it is necessary to add PDU set related information to the RLC PDU header at the sending end so that the RLC entity at the receiving end can determine whether the dependent RLC PDU set is not successfully transmitted. When the dependent RLC PDU set is lost, the RLC entity at the receiving end will send an RLC status report to the RLC entity at the sending end.

[0108] The PDU set related information includes at least one of the following:

[0109] PDU Set type: This field indicates whether the type of the corresponding PDU set is an IPDU set, a P PDU set, or a B PDU set.

[0110] PDU Set Sequence Number: This field indicates the sequence number of the corresponding PDU set.

[0111] PDU Sequence Number in a PDU Set: This field indicates the sequence number of the corresponding PDU contained in the PDU Set.

[0112] Packet priority in a PDU Set: This field indicates whether the corresponding PDU in a PDU Set has the highest priority.

[0113] PI: This field indicates whether the corresponding PDU in the PDU set is the first data packet, the last data packet, or a data packet located between the first and last data packets.

[0114] Dependent PDU Set Sequence Number: This field indicates the sequence number of the dependent PDU set of the corresponding PDU set.

[0115] In addition, since RAN can adopt the Cu-DU separation architecture, the above PDU set related information should also be transmitted through the F1-U interface. Therefore, it is also necessary to add PDU set related information for the sender in the F1-U header.

[0116] 2. Enhancement of RLC status report: Specifically, RLC status report is applicable to RLC acknowledged mode (AM) DRBs and RLC unacknowledged mode (UM) DRBs. When the dependent RLC PDU set is lost, the receiving RLC entity shall send an RLC status report to the transmitting RLC entity. Based on the RLC status report, the transmitting RLC entity shall discard the RLC SDU belonging to the PDU set associated with the dependent RLC PDU set.

[0117] RLC status reporting mechanism:

[0118] Send operation:

[0119] An RLC acknowledged mode (AM) entity or an unacknowledged mode (UM) entity sends a STATUS PDU to its peer AM RLC entity or UM RLC entity to provide an acknowledgement (ACK) or a negative acknowledgement (NACK) of an RLC SDU or part thereof.

[0120] The conditions that trigger the STATUS report include: the dependent RLC PDU set is lost; receiving operation.

[0121] When the STATUS report is triggered, the receiving end of the AM RLC entity or UM RLC entity shall perform the following operations: For each RLC PDU in the PDU set, if there is a 'NACK_SN' (Negative ACK Sequence Number), it is considered as unsuccessfully transmitted. If the PDU set type to which the unsuccessfully transmitted RLC PDU belongs is "IPDU set type", all RLC SDUs of the associated PDU set shall be discarded based on the dependent PDU set sequence number.

[0122] In summary, in order to implement a packet discard mechanism based on the dependency of a PDU set in RAN, the present application proposes a grouping method that supports packet discard. Both PDCP layer packet discard and RLC layer packet discard are considered. The relevant enhancement schemes are as follows: add PDU set dependency information in the PDCP header, RLC header and / or F1-U GTP-U header for transmission of DRBs associated with the XR PDU set on the Uu interface; introduce PDCP status reporting with PDU set granularity; introduce RLC status reporting of RLC unacknowledged mode (UM) RLC entity. The PDU set dependency information includes at least one of the following: PDU set sequence number (PDU SetSN), start and / or end information of the PDU set, PDU sequence number in the PDU set, number of PDUs in the PDU set, importance and / or dependency of the PDU set, priority of packets in the PDU set, position indicator (PI), dependent DRB identifier (DRB ID), and dependent PDU set sequence number. The following terms are used in certain embodiments of the present application: PSDB (PDU-Set Delay Budget): PDU set delay budget, PSER (PDU-Set Error Rate): PDU set bit error rate.

[0123] Fig.13 It is a block diagram of a first wireless communication device 1300, illustrating an embodiment of the present application. The first wireless communication device 1300 includes: a transmitter 1301, configured to send a PDU to a second wireless communication device, and include PDU set related information in a PDU header so that the second wireless communication device can identify the PDU set and its dependent PDU set; a detector 1302, configured to detect a PDU set status report sent by the second wireless communication device, and when a PDU dependent on the PDU set is lost or unsuccessfully transmitted, the status report indicates the situation; a discard circuit 1303, configured to discard an SDU belonging to a PDU set associated with a dependent PDU set when a PDU set status report is detected; the packet discard method is performed by a PDCP entity or an RLC entity of the first wireless communication device.

[0124] Fig.14It is a block diagram of a second wireless communication device 1400, illustrating an embodiment of the present application. The second wireless communication device 1400 includes: a detector 1401, which is used to detect a PDU sent by a first wireless communication device, and read the PDU set related information in the PDU header to determine the PDU set to which the PDU belongs and its dependent PDU set; a transmitter 1402, which is used to send a PDU set status report to the first wireless communication device when a PDU dependent on the PDU set is lost or unsuccessfully transmitted; a controller 1403, which is used to control the first wireless communication device to discard the SDU belonging to the PDU set associated with the dependent PDU set when the PDU set status report is detected; the data packet discarding method is performed by a PDCP entity or an RLC entity of the second wireless communication device.

[0125] In some embodiments, the dependent PDU set includes: at least one IPDU set, at least one P PDU set, and at least one BPDU set. When at least one IPDU set is lost or unsuccessfully transmitted, at least one associated P PDU set and / or at least one associated B PDU set should be discarded. When at least one P PDU set is lost or unsuccessfully transmitted, at least one associated B PDU set should be discarded.

[0126] In some embodiments, the PDU set related information includes at least one of the following: PDU set type, PDU set sequence number (SN), start and / or end information of the PDU set, PDU sequence number in the PDU set, number of PDUs in the PDU set, importance and / or dependency of the PDU set, priority of packets in the PDU set, position indicator (PI), associated data radio bearer (DRB) identifier (ID), dependent PDU set sequence number,

[0127] In some embodiments, the associated PDU sets may be mapped to the same DRB or different DRBs. When the associated PDU sets are mapped to the same DRB and the packet discard method is executed by the PDCP entity of the first wireless communication device, the PDU set related information includes at least one of the following: PDU set type, PDU set SN, PDU SN, PDU priority, PI, dependent PDU set SN. When the associated PDU sets are mapped to different DRBs and the packet discard method is executed by the PDCP entity of the first wireless communication device, the PDU set related information includes at least one of the following: PDU set type, PDU set SN, PDU SN, PDU priority, PI, dependent DRB ID, dependent PDU set SN.

[0128] In some embodiments, based on the PDU set status report, the PDCP entity of the first wireless communication device is configured to notify the associated transmitting PDCP entity of the loss of the dependent PDCP PDU set according to the dependent DRB ID. In some embodiments, the associated transmitting PDCP entity is configured to discard the PDCP SDU belonging to the PDU set associated with the dependent PDCP PDU set. In some embodiments, for an acknowledgement mode (AM) DRB or an unacknowledgement mode (UM) DRB configured by at least one upper layer to send a PDU set status report, when the dependent PDU set is lost or unsuccessfully transmitted, and / or the t-Reordering timer expires, the second wireless communication device triggers a PDU set status report.

[0129] In some embodiments, when the second wireless communication device triggers a PDU set status report, the device performs at least one of the following operations: compiling a PDU set status report, including: setting the first unsuccessfully received PDU set sequence number (SN) to the FMP field; in the bitmap field, setting it to a first value for an incompletely received PDCP SDU or a PDCP SDU that fails to decompress; setting it to a second value for all PDCP SDUs that are completely received or lost; submitting the PDU set status report as the first PDCP PDU to at least one lower layer for transmission by the PDCP entity of the first wireless communication device.

[0130] In some embodiments, for AM DRBs or UM DRBs, when the first wireless communication device receives a PDU set status report, at least one of the following operations is performed: for each PDU set, if the bit value in the bitmap field is a first value, it is deemed to be unsuccessfully transmitted or lost; if the bit value in the bitmap field is a second value, or the value of the dependent PDU set SN is less than the value of the FMP field, it is deemed to be successfully transmitted or lost; when the type of the PDU set that is unsuccessfully transmitted or lost is an IPDU set type: if the associated PDU sets are mapped to the same DRB, the PDCP SDUs of all associated PDU sets should be discarded according to the dependent PDU set SN; if the associated PDU sets are mapped to different DRBs, the PDCP SDUs of all associated PDU sets should be discarded according to the dependent DRB ID and the dependent PDU set SN.

[0131] In some embodiments, when the packet discarding method is performed by the RLC entity of the first wireless communication device, the PDU set related information includes at least one of the following: PDU set type, PDU set sequence number (SN), PDU sequence number within the PDU set, PDU priority within the PDU set, position indicator (PI), dependent PDU set SN, in some embodiments, when the packet discarding method is performed by the RLC entity of the first wireless communication device, the PDU set related information is stored in the RLC header and / or the F1-U header. In some embodiments, the PDU set status report is applicable to RLC AM DRBs and / or RLC UM DRBs. In some embodiments, for the PDU set status report, the AM RLC entity or UM RLC entity of the second wireless communication device sends a status PDU (STATUS PDU) to its peer AM RLC entity or peer UM RLC entity of the first wireless communication device to provide positive (ACK) and / or negative (NACK) confirmation of the RLC SDU or part thereof. In some embodiments, the condition for the AM RLC entity or UM RLC entity of the second wireless communication device to trigger the PDU set status report includes: the dependent PDU set is lost or unsuccessfully transmitted. In some embodiments, when the AM RLC entity or UM RLC entity of the second wireless communication device triggers a PDU set status report, at least one of the following operations is performed by the AM RLC entity or UM RLC entity of the first wireless communication device: for each RLC PDU in the PDU set, if NACK_SN exists, it is deemed to be unsuccessfully transmitted or lost; when the PDU set type to which the unsuccessfully transmitted or lost RLC PDU belongs is an IPDU set type: discard the RLC SDUs of all associated PDU sets based on the dependent PDU set SN.

[0132] Fig.15 7 is a block diagram of an exemplary wireless communication system 700 according to an embodiment of the present application. The embodiments described herein may be implemented into a system using any appropriately configured hardware and / or software. Fig.15 A system 700 is shown, which includes a radio frequency (RF) circuit 710, a baseband circuit 720, an application circuit 730, a memory / storage device 740, a display 750, a camera 760, a sensor 770, and an input / output (I / O) interface 780, which are coupled to each other at least as shown. The application circuit 730 may include circuits, such as but not limited to one or more single-core or multi-core processors. The processor may include any combination of general-purpose processors and special-purpose processors, such as a graphics processor, an application processor. The processor may be coupled to a memory / storage device and configured to execute instructions stored in the memory / storage device to enable various applications and / or operating systems to run on the system.

[0133] While the present disclosure has been described in connection with what is considered to be the most practical and preferred embodiment, it is to be understood that the present disclosure is not limited to the disclosed embodiment, but is intended to cover various arrangements made without departing from the scope of the broadest interpretation of the appended claims.

Claims

1. A method for discarding a data packet, performed by a first wireless communication device, characterized in that: include: The first wireless communication device sends a protocol data unit (PDU) to the second wireless communication device, wherein a PDU header of the PDU includes PDU set related information, and the PDU set related information is used by the second wireless communication device to identify which PDU set the PDU belongs to and the dependent PDU set; The first wireless communication device detects a PDU set-based status report sent by the second wireless communication device, and when a PDU in the dependent PDU set is lost or unsuccessfully transmitted, the PDU set-based status report indicates that the dependent PDU set has been lost or unsuccessfully transmitted; When the PDU set-based status report is detected, the first wireless communication device discards a service data unit SDU belonging to a PDU set associated with the dependent PDU set; The data packet discarding method is executed by a Packet Data Convergence Protocol PDCP entity or a Radio Link Control RLC entity of the first wireless communication device.

2. The method for discarding data packets according to claim 1, characterized in that: The dependent PDU set is an IPDU set, a PPDU set and / or a B PDU set. When at least one IPDU set is lost or unsuccessfully transmitted, at least one associated P PDU set and / or at least one associated B PDU set is discarded, or when at least one P PDU set is lost or unsuccessfully transmitted, at least one associated B PDU set is discarded.

3. The method for discarding data packets according to claim 1, characterized in that: The PDU set related information includes at least one of the following: PDU set type, PDU set sequence number SN, start and / or end of the PDU set, PDU SN in the PDU set, number of PDUs in the PDU set, importance and / or dependency of the PDU set, priority of data packets in the PDU set, location indicator PI, dependent data radio bearer DRB identifier ID, and dependent PDU set SN.

4. The method for discarding a data packet according to any one of claims 1 to 3, characterized in that: Associated PDU sets are mapped to the same DRB or to different DRBs.

5. The method for discarding data packets according to claim 4, characterized in that: When the associated PDU set is mapped to the same DRB and the data packet discard method is executed by the PDCP entity of the first wireless communication device, the PDU set related information includes at least one of the following: PDU set type, PDU set SN, PDU SN in the PDU set, data packet priority in the PDU set, PI, and dependent PDU set SN.

6. The method for discarding data packets according to claim 4, characterized in that: When the associated PDU set is mapped to the different DRB and the data packet discard method is executed by the PDCP entity of the first wireless communication device, the PDU set related information includes at least one of the following: PDU set type, PDU set SN, PDU SN within the PDU set, data packet priority within the PDU set, PI, dependent DRB ID, and dependent PDU set SN.

7. The method for discarding data packets according to claim 6, characterized in that: The dependent DRB ID is configured by the control plane mechanism.

8. The method for discarding data packets according to claim 7, characterized in that: The first wireless communication device and the second wireless communication device notify the first wireless communication device and the second wireless communication device of the dependent DRB ID through a radio resource control RRC reconfiguration process, and establish a DRB.

9. The method for discarding data packets according to claim 6, characterized in that: In the PDU set-based status report, the PDCP entity of the first wireless communication device is configured to notify a dependent sending PDCP entity of a lost dependent PDCP PDU set according to the dependent DRB ID.

10. The method for discarding data packets according to claim 9, characterized in that: The dependent transmitting PDCP entity is configured to discard PDCP SDUs belonging to a PDU set associated with the dependent PDCP PDU set.

11. The method for discarding data packets according to claim 4, characterized in that: For an acknowledgement mode AM DRB or an unacknowledgement mode UM DRB configured by at least one upper layer to send the PDU set-based status report, the PDU set-based status report is triggered by the second wireless communication device when the dependent PDU set is lost or unsuccessfully transmitted and / or t-reordering times out.

12. The method for discarding data packets according to claim 4, characterized in that: When the PDU set-based status report is triggered by the second wireless communication device, the second wireless communication device performs at least one of the following operations: The PDU set-based status report is compiled in the following manner: Set the first missing packet FMP field to the first unsuccessfully received PDU set SN; In the bitmap field, for the PDCP SDUs in the PDU set that are not fully received or fail to be decompressed, set to a first value; In the bitmap field, for all received PDCP SDUs in the PDU set, set to a second value; The PDU set-based status report is submitted as a first PDCP PDU to at least one lower layer for transmission through the PDCP entity of the first wireless communication device.

13. The method for discarding data packets according to claim 4, characterized in that: For an AM DRB or a UM DRB, when the first wireless communication device receives the PDU set-based status report, the first wireless communication device performs at least one of the following operations: Consider, for each PDU set, whether the PDU set set to the first value in the bitmap is not successfully transmitted or lost; Consider, for each PDU set, whether the PDU set set to the second value in the bitmap or the PDU set whose dependent PDU set SN is less than the value of the FMP field is successfully transmitted; When the PDU set type of the unsuccessfully transmitted or lost PDU set is an IPDU set type: if the associated PDU set is mapped to the same DRB, discarding the PDCP SDUs of all associated PDU sets according to the dependent PDU set SN; If the associated PDU set is mapped to the different DRB, the PDCP SDUs of all associated PDU sets are discarded according to the dependent DRB ID and the dependent PDU set SN.

14. The method for discarding data packets according to claim 3, characterized in that: When the data packet discarding method is executed by the RLC entity of the first wireless communication device, the PDU set related information includes at least one of the following: PDU set type, PDU set SN, PDU SN in the PDU set, data packet priority in the PDU set, PI, and dependent PDU set SN.

15. The method for discarding data packets according to claim 1 or 14, characterized in that: When the data packet discarding method is executed by the RLC entity of the first wireless communication device, the PDU set related information is located in the RLC header and / or the F1-U header of the first wireless communication device.

16. The method for discarding data packets according to claim 1 or 15, characterized in that: The PDU set-based status report is used for RLC acknowledged mode AM DRB and / or RLC unacknowledged mode UM DRB.

17. The method for discarding data packets according to claim 16, characterized in that: For the PDU set-based status reporting, a status PDU is sent by the AM RLC entity or UM RLC entity of the second wireless communication device to the peer AM RLC entity or peer UM RLC entity of the first wireless communication device to provide positive and / or negative confirmation of the RLC SDU, or positive and / or negative confirmation of a partial RLC SDU.

18. The method for discarding data packets according to claim 17, characterized in that: The triggering condition for triggering the PDU set-based status report by the AM RLC entity or the UM RLC entity of the second wireless communication device includes that the dependent PDU set is lost or not successfully transmitted.

19. The method for discarding data packets according to claim 17 or 18, characterized in that: When the PDU set-based status report is triggered by the AM RLC entity or the UM RLC entity of the second wireless communication device, the AM RLC entity or the UM RLC entity of the first wireless communication device performs at least one of the following operations: Consider for each RLC PDU whether there is any NACK_SN marked as unsuccessful transmission or loss; When the PDU set type to which the unsuccessfully transmitted or lost RLC PDU belongs is an IPDU set type, all RLC SDUs of the associated PDU set are discarded according to the dependent PDU set SN.

20. A method for discarding a data packet, performed by a second wireless communication device, characterized in that: include: The second wireless communication device detects a protocol data unit PDU sent by the first wireless communication device, wherein a PDU header of the PDU includes the PDU set related information, wherein the PDU set related information is used by the second wireless communication device to identify which PDU set the PDU belongs to and the dependent PDU set; When the dependent PDU set is lost or unsuccessfully transmitted, the second wireless communication device sends a PDU set-based status report to the first wireless communication device, wherein the PDU set-based status report indicates that the dependent PDU set is lost or unsuccessfully transmitted; When the PDU set-based status report is detected, controlling the first wireless communication device to discard a service data unit SDU belonging to a PDU set associated with the dependent PDU set; The data packet discarding method is executed by a Packet Data Convergence Protocol PDCP entity or a Radio Link Control RLC entity of the second wireless communication device.

21. A first wireless communication device, characterized in that: include: Memory; Transceiver; as well as a processor coupled to the memory and the transceiver; Wherein, the processor is configured to execute the method of any one of claims 1 to 19.

22. A second wireless communication device, characterized in that: include: Memory; Transceiver; as well as a processor coupled to the memory and the transceiver; Wherein, the processor is configured to execute the method of claim 20.

23. A non-transitory machine-readable storage medium, characterized in that: Instructions are stored thereon, and when a computer executes the instructions, the instructions cause the computer to perform the method of any one of claims 1 to 20.

24. A chip, characterized in that: include: A processor configured to call and run a computer program stored in a memory so that a device equipped with the chip executes a method according to any one of claims 1 to 20.

25. A computer-readable storage medium, characterized in that: A computer program is stored therein, wherein the computer program causes a computer to execute the method of any one of claims 1 to 20.

26. A computer program product, characterized in that Comprising a computer program, wherein the computer program causes a computer to perform the method of any one of claims 1 to 20.

27. A computer program, characterized in that The computer program causes a computer to execute the method of any one of claims 1 to 20.

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