Wireless communication method and device for augmented reality traffic

Abstract

The present disclosure provides a wireless communication method, which can be performed in a wireless communication device operating as a transmitter device, comprising: receiving a plurality of data packets of corresponding frames in an augmented reality (XR) stream of an XR service, wherein each data packet in the plurality of data packets of the corresponding frame comprises a protocol data unit (PDU) header carrying a data packet identifier of the data packet; configuring a transmission window based on the corresponding frame of the XR stream and a timer of the transmission window; determining whether to discard a data packet related to the data packet identifier based on the data packet identifier; when the data packet identifier of the data packet is in the transmission window of the corresponding frame, transmitting the data packet to a lower layer; and when the data packet identifier of the data packet exceeds the transmission window of the corresponding frame, discarding the data packet.

Description

Technical Field

[0001] The present disclosure relates to the field of communication systems, and in particular, to a wireless communication method and device for extended reality (XR) traffic. Background Art

[0002] Wireless communication systems, such as the 3rd Generation (3G) mobile phone standards and technologies are well known. The 3G standards and technologies were developed by the 3rd Generation Partnership Project (3GPP). The 3rd Generation of wireless communications is generally developed to support macrocellular mobile phone communications. Communication systems and networks have evolved towards broadband and mobile systems. In a cellular wireless communication system, a user equipment (UE) is connected to a radio access network (RAN) via a radio link. The RAN includes a set of base stations (BSs) that provide radio links to UEs located within the cell covered by the base station, as well as an interface to a core network (CN) that provides overall network control. As is well known, the RAN and CN each perform corresponding functions in the overall network. 3GPP developed the so-called Long Term Evolution (LTE) system, the Evolved Universal Mobile Telecommunication System Territorial Radio Access Network (E-UTRAN), for mobile access networks, where one or more macro cells are supported by a base station called eNodeB or eNB (evolved NodeB). Recently, LTE is evolving further to the so-called 5G or NR (New Radio) system, where one or more cells are supported by a base station called gNB. Technical issues

[0003] 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. In 5G or NR, features supporting eMBB, URLLC, and mMTC were introduced in Release 15 and enhanced in Releases 16 and 17.

[0004] Extended Reality (XR) and cloud gaming services are important media applications supported by 5G. In 3GPP, a series of research projects have been completed and it has been found that XR services have some unique characteristics in terms of traffic characteristics, and the current 5G system may not be able to support XR services well. Some characteristics of XR traffic are listed below: ●A unique feature of XR traffic is that each data packet has the attributes of a frame. From the perspective of network transmission, each video frame in an XR service may be segmented into one or more data packets. Generally, a video frame can only be correctly decoded and reconstructed when all related multiple data packets are correctly received. Another feature of XR traffic is that XR services are time-sensitive, and each frame should arrive at the client of the XR application within a specified time window. It is well known that it is meaningless to transmit outdated data packets to the client terminal of the XR application. However, according to the current 3GPP architecture, the association between an XR frame and multiple data packets belonging to the XR frame has not been discussed in the NR standardization work. Therefore, when some data packets constituting a frame arrive at the Radio Access Network (RAN) (e.g., a UE or a base station in the RAN), if the RAN cannot transmit these data packets within the required delay, the RAN may still try to transmit these data packets without knowing the association between the multiple data packets and the frame. That is, if a frame and its multiple data packets cannot be identified, the Quality of Service (QoS) of the XR service cannot be guaranteed, and potential unnecessary transmission may reduce network capacity. ●Multiple data streams: According to the XR service traffic model agreed upon in the 3GPP RAN1 Release 17 XR Study Item (SI), there are three options for the multi-stream model of downlink (DL) XR traffic: ■Option 1: I frame + P frame; ■Option 2: Video + Audio / Data; and ■Option 3: Field of View (FOV) + ​​omnidirectional stream.

[0005] In Option 1, I-frames are referred to as intra-coded frames or independent frames, and P-frames are referred to as predicted frames. In the XR service, the XR traffic stream of Option 1 includes an I-frame stream and a P-frame stream. In Option 2, video, audio, and data represent video streams, audio streams, and data streams in the XR traffic stream, respectively. The XR traffic stream of Option 2 includes a video stream and an audio / data stream. In Option 3, FOV represents a Field of Vision (FOV) stream in the XR traffic stream. The XR traffic stream of Option 3 includes a FOV stream and an omnidirectional stream.

[0006] The multi-stream model for uplink (UL) XR traffic also has three options: Option 2: Gesture / control + aggregated scene, video, data and audio Option 3A: Gesture / Control + Aggregate Scene and Video Streams + Aggregate Audio and Data Streams; and ●Option 3B: gesture / control + I stream of video + P stream of video.

[0007] In options 2, 3A, and 3B for UL XR traffic, attitude / control represents the attitude and control information flow of the XR traffic flow. Due to the different delays caused by encoding / rendering and network transmission for different flows, different flows from the same XR service may have different packet arrival times even if all flows have the same periodicity and start time. However, from the perspective of intelligent radio bearer control and adaptive scheduling in RAN, RAN may require multi-flow synchronization based on packets or frames to perform intelligent radio bearer control and adaptive scheduling for the flows of XR traffic.

[0008] Therefore, a method is needed to process data packets for XR services. Summary of the invention

[0009] The objective of the present disclosure is to provide a user equipment (UE), a base station and a wireless communication method.

[0010] In a first aspect, an embodiment of the present invention provides a wireless communication method that can be performed in a wireless communication device operating as a transmitter device, comprising: Receive multiple data packets of corresponding frames in an XR stream of an extended reality XR service, wherein each of the multiple data packets of the corresponding frame includes a protocol data unit (PDU) header carrying a data packet identifier of the data packet; configuring the transmission window based on the corresponding frame of the XR stream and a timer of the transmission window; Determining whether to discard a data packet associated with the data packet identifier based on the data packet identifier; When the data packet identifier of the data packet is within the transmission window of the corresponding frame, delivering the data packet to a lower layer; and When the data packet identifier of the data packet exceeds the transmission window of the corresponding frame, the data packet is discarded.

[0011] In a second aspect, an embodiment of the present invention provides a wireless communication, including a processor, wherein the processor is configured to call and run a computer program stored in a memory so that a device equipped with the processor executes the disclosed method.

[0012] The disclosed method can be implemented in a chip. The chip may include a processor configured to call and run a computer program stored in a memory so that a device equipped with the chip executes the disclosed method.

[0013] The disclosed method can be programmed as computer executable instructions stored in a non-transitory computer readable medium. When the non-transitory computer readable medium is loaded into a computer, the processor of the computer is instructed to execute the disclosed method.

[0014] The non-transitory computer-readable medium may include at least one of the following: a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an EPROM, an electrically erasable programmable read-only memory, and a flash memory.

[0015] The disclosed method can be programmed as a computer program product, which enables a computer to perform the disclosed method.

[0016] The disclosed method can be programmed as a computer program, which enables a computer to perform the disclosed method. Beneficial effects

[0017] Embodiments of the present invention provide: ●A method of identifying multiple packets of a frame in a transmission network. ●A method for extending a data packet identifier of a transport frame based on the Real-time Transport Protocol (RTP) and the RTP header. ●A method for discarding outdated packets based on a timer, a transmission window, and an identifier that identifies the frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present disclosure or related technologies, the following briefly introduces the drawings to be described in the embodiments. Obviously, these drawings are only some embodiments of the present disclosure. A person of ordinary skill in the art can obtain other drawings based on these drawings without paying any prerequisites.

[0019] Figure 1 Schematic diagram showing an example of a telecommunications system.

[0020] Figure 2 A schematic diagram showing a network embodiment of the disclosed wireless communication method.

[0021] Figure 3 Diagram showing an example of a protocol stack of entities involved in an XR service.

[0022] Figure 4 A schematic diagram showing a wireless communication method according to an embodiment of the present disclosure.

[0023] Figure 5 A schematic diagram showing a wireless communication method according to an embodiment of the present disclosure.

[0024] Figure 6 Example diagram showing XR service downlink (DL) flow.

[0025] Figure 7 Example diagram showing XR service uplink (UL) flow.

[0026] Figure 8 Diagram showing the protocol stack and several XR packet examples.

[0027] Fig. 9 Diagram showing another example of the protocol stack and multiple XR packets.

[0028] Fig.10 A schematic diagram showing an example of a potential protocol stack for the adaptation layer in the disclosed method.

[0029] Fig.11 Diagram showing an example of an RTP generic packet header.

[0030] Fig.12 Diagram showing an example of an RTP single-byte header.

[0031] Fig.13 Diagram showing an example of an RTP two-byte header.

[0032] Fig.14 A schematic diagram showing a first example of RTP header extension.

[0033] Fig.15 A schematic diagram showing a second example of RTP header extension.

[0034] Fig.16 A schematic diagram showing a third example of RTP header extension.

[0035] Fig.17 A schematic diagram showing a fourth example of RTP header extension.

[0036] Fig.18 Diagram showing an example of a transfer window.

[0037] Fig.19 A diagram showing an example of signaling Quality of Service (QoS) requirements for XR services.

[0038] Fig. 20 A schematic diagram showing a wireless communication system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0039] In conjunction with the accompanying drawings, the following describes in detail the technical matters, structural features, achieved goals and effects of the embodiments of the present disclosure. Specifically, the terms in the embodiments of the present disclosure are only used for the purpose of describing specific embodiments, rather than limiting the present disclosure.

[0040] The present invention discloses a wireless communication method for extended reality (XR) traffic to process multiple data packets of multiple frames in an XR service. The XR service may include augmented reality (AR), virtual reality (VR) or mixed reality (MR).

[0041] Reference Figure 1 A telecommunication system including a user equipment (UE) 10a, a UE 10b, a base station (BS) 20a and a network entity device 30 performs the disclosed method according to an embodiment of the present disclosure. Figure 1For illustration only, not limitation, the system may include more UE, BS and CN entities. The connections between the devices and device components in the figure are represented by lines and arrows. The UE 10a may include a processor 11a, a memory 12a and a transceiver 13a. The UE 10b may include a processor 11b, a memory 12b and a transceiver 13b. The base station 20a may include a processor 21a, a memory 22a and a transceiver 23a. The network entity device 30 may include a processor 31, a memory 32 and a transceiver 33. Each of the processors 11a, 11b, 21a and 31 may be configured to implement the functions, procedures and / or methods proposed in the description. The layers of the wireless interface protocol may be implemented in the processors 11a, 11b, 21a and 31. Each of the memories 12a, 12b, 22a and 32 can be operated to store various programs and information to operate the connected processors. Each of the transceivers 13a, 13b, 23a and 33 is operably coupled to a connected processor to transmit and / or receive wireless signals or wired signals. The UE 10a may communicate with the UE 10b via a side link. The base station 20a may be an evolved Node B (eNB), a next generation Node B (gNB) or one of other types of wireless nodes, and may configure wireless resources for the UE 10a and UE 10b.

[0042] The network entity device 30 may be a node in the core network (CN). The CN may include LTE CN or 5G Core (5G Core, 5GC), including User Plane Function (UPF), Session Management Function (SMF), 5G Core Network Access and Mobility Management Function (AMF), Unified Data Management (UDM), Policy Control Function (PCF), Control Plane (CP) / User Plane (UP) Separation (CUPS), Authentication Server Function (AUSF), Network Slice Selection Function (NSSF) and Network Exposure Function (NEF).

[0043] Examples of UEs described herein may include one of UE 10a or UE 10b. Examples of base stations described herein may include the base station 20a. Uplink (UL) transmission of control signals or data may be a transmission operation from the UE to the base station. Downlink (DL) transmission of control signals or data may be a transmission operation from the base station to the UE. The DL control signal may include downlink control information (DCI) or radio resource control (RRC) signals from the base station to the UE.

[0044] Figure 2It is an Extended Reality (XR) service transmission network model supported by the fifth generation (5G) system. User Equipment (UE) 10 is a 5G terminal that supports XR services and XR applications, and can be called a client, client terminal or XR client. Next Generation Node B (gNB) 20 is a 5G wireless node. The gNB 20 communicates with the UE 10 and provides NR user plane and control plane protocol termination to the UE through the New Radio (NR) Uu interface. The gNB 20 is connected to the 5G Core Network (5GC) 300 through the NG interface. The User Plane Function (UPF) 30b is the UPF in the 5GC 300, and the 5GC 300 is the 5G Core Network. The Data Network (DN) 40 is the DN where the XR server 41 that provides XR services is located. The DN 40 can provide network operator services, Internet access or third-party services. The XR server 41 may include a processor 411, a memory 412, and a transceiver 413. The processor 411 may be configured to implement the XR service-related functions, programs, and / or methods described. The wireless interface protocol layer may be implemented in the processor 411. The memory 412 may be operable to store various programs and information to operate the connected processor. The transceiver 413 is operatively coupled to the connected processor to send and / or receive wireless signals or wired signals.

[0045] Each of the processors 411, 11a, 11b, 21a and 31 may include an Application-Specific Integrated Circuit (ASIC), other chipsets, logic circuits and / or data processing devices. Each of the memories 412, 12a, 12b, 22a and 32 may include a Read-Only Memory (ROM), a Random Access Memory (RAM), flash memory, a memory card, a storage medium and / or other storage devices. Each of the transceivers 413, 13a, 13b, 23a and 33 may include a baseband circuit and a Radio Frequency (RF) circuit to process radio frequency signals. When the embodiment is implemented in software, the techniques described herein may be implemented by modules, programs, functions, entities, etc. that perform the functions described herein. These modules may be stored in a memory and executed by a processor. The memory may be implemented inside or outside a processor, where it may be communicatively coupled to the processor in various known ways. The device that performs the wireless communication method may be a sending device that sends an XR traffic stream of an XR service to a receiving device, or a receiving device that receives an XR traffic stream. The XR traffic flow may include one or more XR flows of the XR service. For example, the device performing the wireless communication method may include the gNB 20, the XR server 41 in the data network 40, or the UE. That is, the XR server 41 in the data network 40 may operate as a sending device performing the wireless communication method in certain XR traffic delivery scenarios, and the UE 10 may operate as a receiving device receiving the XR traffic flow from the sending device. Similarly, the UE 10 may perform the wireless communication method as a sending device in certain XR traffic delivery scenarios, and the XR server 41 may operate as a receiving device receiving the XR traffic flow from the sending device. Alternatively, the sending device may include an intermediate device between the UE 10 and the XR server 41. The UE 10 may include an embodiment of the UE 10a or the UE 10b. The gNB 20 may include an embodiment of the base station 20a. It should be noted that although the description uses gNB 20 and UPF / 5GC 30b as examples, the wireless communication method may be performed by a base station, such as another gNB, an evolved Node B (eNB), a base station integrating eNB and gNB, or a base station for beyond 5G technology. The UPF / 5GC 30b may include another network entity of 5GC.

[0046] One or more steps (or modules) in the embodiments of the present disclosure may be implemented as a computer program, instruction, or software module and stored in a memory of a sending device, or may be implemented as a circuit or hardware module in a processor of a sending device, or may be implemented as an integrated circuit (IC) chip, circuit, or plug-in of a sending device.

[0047] Figure 3 An example of the overall protocol stack between the UE 10 and the XR server 41 is shown, including intermediate entities (i.e., the gNB 20 and the UPF 30a). The communication between any two entities in the same protocol layer is represented by arrows. Figure 3 The protocol layers in have been standardized and are briefly described as follows: ● Adaptation layer: A virtual stack or layer that adapts application data to multiple packets in a format suitable for the transport network, or adapts multiple packets in a suitable format from the transport network. The adaptation layer will be standardized by the 3rd Generation Partnership Project (3GPP) and may include one or more sublayers and may refer to one or more existing specifications. ●5G User Plane (UP) encapsulation: A virtual stack or layer that will be standardized by 3GPP into appropriate specifications, such as GPRS Tunnelling Protocol User Plane (GTP-U). ●L1: Internet physical layer, which can be any suitable first-layer technology, such as point-to-point or point-to-multipoint technology. ●L2: Internet data link layer, which can be any suitable data link layer protocol, such as Point-to-Point Protocol (PPP), Ethernet, etc. ●IP: "Internet Protocol", please refer to the "Internet Protocol Version 6 (IPv6) Specification" in the Internet Engineering Task Force (IETF) RFC 791 or IETF RFC 8200. ●UDP: "User Datagram Protocol", please refer to IETF RFC 768 (1980-08). ●GTP-U: "General Packet Radio Service (GPRS) Tunneling Protocol User Plane (GTPv1-U)", please refer to 3GPPTS29.281. ●PHY: New air interface physical layer, refer to 3GPP TS 38.211 to 38.215. ●MAC: New air interface Media Access Control (MAC) protocol, please refer to 3GPP TS38.321. ●RLC: New air interface radio link control (RLC) protocol, please refer to 3GPP TS38.322. ●PDCP: Packet Data Convergence Protocol (PDCP), please refer to 3GPP TS 38.323. ●SDAP: Evolved Universal Terrestrial Radio Access (E-UTRA) and New Radio Service Data Adaptation Protocol (SDAP), please refer to 3GPP TS 37.324. Each layer of one or more protocols may be implemented as a module, entity or unit for processing the one or more protocols. For example, the application layer in a sending device (such as UE 10 or XR server 41) or a receiving device (such as XR server 41 or UE 10) may include an application entity of the sending device or the receiving device. Similarly, the adaptation layer in a sending device (such as UE 10 or XR server 41) or a receiving device (such as XR server 41 or UE 10) may include an adaptation entity of the sending device or the receiving device. The SDAP layer in a sending device, a receiving device or an intermediate device (such as gNB 20 or UPF 30a) may include an SDAP entity of the sending device, the receiving device or the intermediate device. The PDCP layer in a sending device, a receiving device or an intermediate device may include a PDCP entity of the sending device, the receiving device or the intermediate device. The RLC layer in a sending device, a receiving device or an intermediate device may include an RLC entity of the sending device, the receiving device or the intermediate device. The MAC layer in a sending device, a receiving device or an intermediate device may include a MAC entity of the sending device, the receiving device or the intermediate device. The PHY layer in the transmitting device, the receiving device, or the intermediate device may include a PHY entity of the transmitting device, the receiving device, or the intermediate device. The 5G UP encapsulation layer in the transmitting device, the receiving device, or the intermediate device may include a 5G UP encapsulation entity of the transmitting device, the receiving device, or the intermediate device. The GTP-U layer in the transmitting device, the receiving device, or the intermediate device may include a GTP-U entity of the transmitting device, the receiving device, or the intermediate device. The UDP / IP layer in the transmitting device, the receiving device, or the intermediate device may include a UDP / IP entity of the transmitting device, the receiving device, or the intermediate device. The L2 layer in the transmitting device, the receiving device, or the intermediate device may include an L2 entity of the transmitting device, the receiving device, or the intermediate device. The L1 layer in the transmitting device, the receiving device, or the intermediate device may include an L1 entity of the transmitting device, the receiving device, or the intermediate device.

[0048] The video stream of the XR service will be periodically encoded and compressed in the form of frames, and the corresponding frame period is 1 / 60 second, 1 / 90 second or 1 / 120 second. Since the sending device may divide the video stream of the XR service into multiple transmission units, encapsulate and transmit each transmission unit into a transmission data packet transmitted across the network, the transmission mechanism of the XR service is actually based on data packets rather than frames. The size of each of the multiple data packets may be variable, the number of the multiple data packets may be variable, and can be configured based on one or more quality of service (QoS) requirements and characteristic parameters of the XR service, such as packet delay budget (PDB), packet error rate (PER), packet loss rate (PLR), frame error rate, frame delay budget, resolution, frame rate and / or data rate.

[0049] Reference Figure 4 and Figure 5 , a sending device performs an embodiment of the disclosed method.

[0050] An embodiment of the present disclosure provides a wireless communication method for identifying a data packet of a frame, inserting an identifier of the frame into the data packet, and transmitting the data packet in a transmission network or discarding it as an obsolete data packet based on the identifier.

[0051] One embodiment of the disclosed method includes the following steps for identifying and processing a plurality of packets of a frame: ● in an identifier insertion layer, inserting a packet identifier into a protocol data unit (PDU) header of each packet of a plurality of packets of a corresponding frame in an XR stream of the XR service (module 100), wherein the packet identifier comprises at least one of a frame identifier or a packet identifier, the frame identifier being capable of uniquely identifying at least a frame of the plurality of packets among a predetermined number of consecutive different frames of the XR stream, and the packet identifier being defined as identifying each packet of a frame or all packets of a frame; ● In a header processing layer, receiving a plurality of data packets of the corresponding frame in the XR stream of the XR service, wherein each of the plurality of data packets of the corresponding frame comprises a PDU header carrying a data packet identifier of the data packet (module 101); ● In the packet discarding layer, determining whether to discard the data packet associated with the data packet identifier based on the data packet identifier (module 103); When the packet identifier of the packet is within the transmission window of the corresponding frame, delivering the packet to a lower layer (module 104); and ●When the data packet identifier of the data packet exceeds the transmission window of the corresponding frame, discard the data packet (module 105).

[0052] The packet identifier is a temporary identifier because it is inserted into the PDU header by the adaptation layer (or application layer) of the sending device and removed by the header processing layer of the sending device. The packet identifier is a frame-packet association identifier because it associates multiple packets to a corresponding frame. The packet identifier is an inter-layer message because it is generated by the adaptation layer (or application layer) of the sending device and processed and removed by the header processing layer of the sending device.

[0053] Reference Figure 5 ,An embodiment of the disclosed method also includes obtaining and removing the data packet identifier from the PDU header of the data packet (module 102).

[0054] In one embodiment, inserting the packet identification into the PDU header of each of the plurality of packets of the corresponding frame is performed in an identifier insertion layer at a source point of the XR stream of the XR service.

[0055] In one embodiment, obtaining and removing the data packet identifier from the PDU header of the data packet is performed in the header processing layer of the sending device.

[0056] In one embodiment, determining whether to discard the data packet associated with the data packet identifier, delivering the data packet, and discarding the data packet are performed in a data packet discard layer of the sending device.

[0057] In one embodiment, the identifier insertion layer includes an application layer or an adaptation layer of the sending device.

[0058] In one embodiment, the header processing layer includes a Packet Data Convergence Protocol (PDCP) layer or a Service Data Adaptation Protocol (SDAP) layer of the sending device.

[0059] In one embodiment, the data packet discard layer includes a packet data convergence protocol (PDCP) layer or a radio link control (Radio Link Control, RLC) layer of the sending device.

[0060] One embodiment of the disclosed method includes the following steps for identifying and processing a plurality of packets of a frame: ● a frame processing layer (such as an application layer or an adaptation layer) inserting a packet identifier into an adaptation layer protocol data unit (PDU) header of each of a plurality of packets of a corresponding frame in an XR stream of the XR service, wherein the packet identifier comprises at least one of a frame identifier or a packet identifier, the frame identifier can at least uniquely identify a frame of the plurality of packets among a predetermined number of consecutive different frames of the XR stream, and the packet identifier is defined as identifying each packet of a frame or all packets of a frame; The header processing layer (such as the PDCP layer) obtains and removes the packet identifier from the PDU header of one of the multiple packets of the corresponding frame; ●determining in a packet discard layer whether to discard a data packet associated with the data packet identifier based on the data packet identifier; The packet discard layer delivers the packet to a lower layer (such as an RLC layer) when the packet identifier of the packet is within the transmission window of the corresponding frame; and When the data packet identifier of the data packet is not within the transmission window range of the corresponding frame, the data packet discarding layer discards the data packet.

[0061] PDCP stands for Packet Data Convergence Protocol (PDCP) and RLC stands for Radio Link Control (RLC). Obtaining and removing packet identifiers may be performed at the PDCP layer or the SDAP layer. In this description, packet identifiers may be referred to as identifiers, and outdated packets are packets of frames that do not meet frame timing requirements. For example, the timing requirement specifies that multiple packets of a frame should be transmitted within a transmission window defined for the frame. A frame of an XR service (such as a video frame) may be segmented into one or more packets for transmission over the network. These multiple packets may be referred to as packets corresponding to the frame or corresponding packets of the frame. The frame may be referred to as a frame corresponding to these packets or a corresponding frame of these packets.

[0062] In one embodiment of the disclosed method, the packet identifier of the data packet of the frame is transmitted using the Real-time Transport Protocol (RTP), and an RTP header extension may be inserted: ●In RTP PDU, the "X" field of the RTP header shall be set to "1"; ●Identifier of the data packet in the transmission frame using RTP header extension.

[0063] A sending device of an XR stream of an XR service may perform an embodiment of the disclosed method to discard outdated data packets of a frame based on the following factors: ●Configurable timers and / or transmission windows; ●The data packet identifier is the frame serial number (Serial Number, SN) of each data packet. Identify the packets of the frame:

[0064] like Figure 6 and Figure 8 As shown, one embodiment of the disclosed method is used for a downlink (DL) XR stream 501, that is, from an XR server 41 to an XR client (such as UE 10), and includes the following detailed steps: ● An XR frame (e.g., a video frame) 40 from an application layer XR application may be segmented into one or more packets 400 at the adaptation layer. For each packet 410, the adaptation layer inserts a packet identifier 401 into the adaptation layer header of the packet 410 and passes the packet 410 to the SDAP layer. The SDAP layer processes the packet as a protocol data unit (PDU) by adding an SDAP header to the packet. The SDAP layer transmits the packet as a service data unit (SDU) to the PDCP layer. ●When receiving the SDU from the SDAP layer, the PDCP layer obtains and removes the data packet identifier 401 from the adaptation layer header, compresses and passes the data packet to the RLC layer and lower layers (i.e., MAC and PHY layers) for transmission through the Radio Access Network (RAN) and the 5G Core (5GC).

[0065] Multiple data packets of the frame of the downlink XR stream 501 are sent from the application layer of the XR server 41 (ie, the source of the downlink XR stream 501) to the application layer of the UE 10 (ie, the destination of the downlink XR stream 501). Figure 6 As shown, multiple data packets in the downlink XR flow 501 are processed along each layer of the downlink XR flow 501. It should be noted that, in one embodiment, the insertion of the data packet identifier may be performed at the adaptation layer of the XR server 41, while the determination of whether to discard the data packet associated with the data packet identifier and the discarding operation are performed at the PDCP layer of the gNB 20.

[0066] like Figure 7 and Fig. 9 As shown, for the uplink video stream 502, that is, from the XR client (such as UE 10) to the XR server 41, the corresponding detailed process is similar to the downlink. ● An XR frame (e.g., a video frame) 50 of an application layer XR application from an XR server 51 may be segmented into one or more data packets 500 at the adaptation layer. For each data packet 510, the adaptation layer inserts a data packet identifier 501 into the adaptation layer header of the data packet 510 and passes the data packet 510 to the SDAP layer. The SDAP layer processes the data packet as a protocol data unit (PDU) by adding an SDAP header to the data packet. The SDAP transmits the data packet as a service data unit (SDU) to the PDCP layer. ●When receiving the SDU from the SDAP layer, the PDCP layer obtains and removes the data packet identifier 501 from the adaptation layer header, compresses and passes the data packet to the RLC layer and lower layers (i.e., MAC and PHY layers) for transmission through the RAN and 5GC.

[0067] The inserting operation is performed in the adaptation layer, and the obtaining operation is performed in the PDCP layer of the UE 10. As for the obtaining and removing functions in the PDCP layer, the function may be part of the header compression function or may be a separate function in the PDCP layer.

[0068] The data packets of the frames of the uplink XR stream 502 are sent from the application layer of the UE 10 (ie, the source of the uplink XR stream 502) to the application layer of the XR server 41 (ie, the destination of the uplink XR stream 502). Figure 7 As shown, multiple data packets in the uplink XR stream 502 are processed along each layer of the uplink XR stream 502. It should be noted that, in one embodiment, the insertion of the data packet identifier may be performed at the adaptation layer of the UE 10, and the determination of whether to discard the data packet associated with the data packet identifier and the discarding operation are performed at the PDCP layer of the UE 10 or the PDCP layer of the gNB 20.

[0070] In another embodiment, the function of obtaining and removing the data packet identifier (ie, obtaining and removing the data packet identifier) ​​is located in the SDAP layer. Frame level identifier:

[0071] The data packet identifier may be a sequence number (SN) of a corresponding extended reality (XR) frame (eg, a video frame), such that all data packets of a frame have the same data packet identifier. Packet level identifiers and frame level identifiers:

[0072] In another embodiment, the packet identification of each data packet corresponding to a frame includes an identifier for the data packet and an identifier for the corresponding frame. The identifier of the data packet is a packet-level identifier for identifying the data packet among multiple data packets corresponding to the frame, and the identifier of the corresponding frame is a frame-level identifier for identifying the frame corresponding to the data packet among multiple frames. For example, the identifier of the data packet is a packet sequence number (SN) of the data packet in the frame, and the identifier of the corresponding frame is a frame SN of the frame.

[0073] The data packet SN may be counted up or down according to the counting sequence of a modulus counter, so that the data packet SN is reset to the initial SN when the counting sequence of the counter ends (i.e., overflows or underflows). Similarly, the frame SN may be counted up or down according to the counting sequence of another modulus counter, so that the frame SN is reset to the initial SN when the counting sequence of the counter ends (i.e., overflows or underflows). The data packet SN and / or the frame SN may be generated locally in the adaptation layer or received from the application layer. Identifier for packets transporting frames using the Real-time Transport Protocol (RTP) header extension:

[0074] Fig.10 An example of a potential protocol stack for the adaptation layer in the disclosed method is shown. The model includes multiple protocol sublayers, and the RTP protocol is used to transmit multiple data packets of frames of the XR service. The packet identifier is inserted into the header extension of the RTP header in the protocol data unit (PDU) header.

[0075] As we all know, the RTP protocol is designed for end-to-end, real-time streaming media transmission. The protocol provides jitter compensation and the ability to detect packet loss and out-of-order delivery, which are common in User Datagram Protocol (UDP) transmission over IP networks. The RTP general packet header is as follows: Fig.11 shown.

[0076] Some fields of the RTP header are as follows: ●X (Extended): 1-bit field indicating whether there is an extended header between the header and the payload data of the data packet. The extended header can be application-specific or profile-specific. ● Header Extension: An optional field whose presence is indicated by the Extension field (i.e., field X). The first 32-bit word in the header extension contains a profile-specific identifier (16 bits) and a length indicator (16 bits), the latter indicating the length of the extension (in 32-bit units, excluding the 32 bits of the extension header). The extension header data content is described in detail below.

[0077] In addition, in the latest version of RTP (RFC 5285), two types of extended headers are used, including one-byte headers and two-byte headers. The details are as follows: ●One-byte header: ■Reference Fig.12 , a one-byte header consisting of the following fields: ◆0xBE: one-byte header; ◆0xDE: one-byte header; ◆Length = 3: three extension headers; ◆L=0: L is the length of the data following the extended header. ●Two-byte header: ■Reference Fig.13 ,The two-byte header includes multiple fields.

[0078] The present invention provides various embodiments of a wireless communication method for data packet identification of a data packet of an RTP protocol and an RTP header extension transmission frame.

[0079] refer to Fig.14 In one embodiment, the RTP protocol data unit (PDU) and its one-byte header extension are defined as follows: ● In the RTP PDU, the field "X" is set to "1", indicating that the RTP header contains one or more header extensions carrying packet identifiers; ●Append a header extension to identify the data packet of the frame, the format is as follows: ■The "ID" field of the header extension can be predefined or dynamically generated and has a length of 4 bits. ■The "L" field of the header extension indicates the number of data fields used for the packet identifier and / or frame identifier. For example, the "L" field can be set to "1", indicating that there is only one byte of data field, including two subfields, one for the packet identifier and the other for the frame identifier, and each subfield is 4 bits long. ■The packet identifier uniquely identifies a packet among multiple packets of a frame of an XR stream corresponding to an XR service. For example, the packet identifier of each packet may be the SN of the packet in the frame, and the maximum number of packets in a frame is 16. ■The frame identifier identifies a frame corresponding to the data packet in a predefined number of consecutive frames and is incremented for each predefined number of consecutive different frames. For example, the frame identifier of each frame may be a frame SN of the frame. The predefined number of frame SNs is 16.

[0080] refer to Fig.15 In another embodiment, the RTP PDU and its one-byte header extension are defined as follows: ● In the RTP PDU, the field "X" shall be set to "1", indicating that the RTP header contains one or more header extensions carrying packet identifiers; ●Append a header extension to identify multiple packets in the same frame, the format is as follows: ■The "ID" field of the header extension can be predefined or dynamically generated and has a length of 4 bits. ■The "L" field of the header extension indicates the number of data fields used for the packet identifier and / or frame identifier. For example, the "L" field can be set to "1", indicating that only one byte of the data field is used for the frame identifier. ■The frame identifier identifies a frame corresponding to the data packet in a predefined number of consecutive frames and is incremented for each predefined number of consecutive different frames. For example, the frame identifier of each frame may be a frame SN of the frame. The predefined number of frame SNs is 256. ■For each data packet of the same frame, the frame identifier is the same.

[0081] refer to Fig.16 In another embodiment, the RTP PDU and its two-byte header extension are defined to be longer, as shown below: ● In the RTP PDU, the field "X" shall be set to "1", indicating that the RTP header contains one or more header extensions carrying packet identification; ●Append a header extension to identify multiple packets in the same frame, the format is as follows: ■The "ID" field of the header extension can be predefined or dynamically generated. ■The "L" field of the header extension indicates the number of data fields used for the packet identifier and / or frame identifier. For example, the "L" field can be set to "2", indicating a 2-byte data field, including two subfields, one for the packet identifier and the other for the frame identifier, each subfield is 1 byte long. ■The packet identifier uniquely identifies a packet among multiple packets of a frame of an XR stream corresponding to an XR service. For example, the packet identifier of each packet may be the SN of the packet in the frame, and the maximum number of packets in a frame is 256. ■The frame identifier identifies a frame corresponding to the data packet in a predefined number of consecutive frames and is incremented for each predefined number of consecutive different frames. For example, the frame identifier of each frame may be a frame SN of the frame. The predefined number of frame SNs is 256.

[0082] refer to Fig.17 In another embodiment, the RTP PDU and its two-byte header extension are defined to be longer, as shown below: ● In the RTP PDU, the field "X" shall be set to "1", indicating that the RTP header contains one or more header extensions carrying packet identification; ●Append a header extension to identify multiple packets in the same frame, the format is as follows: ■The "ID" field of the header extension can be predefined or dynamically generated and has a length of 1 byte; ■The "L" field of the header extension indicates the number of data fields used for the packet identifier and / or frame identifier. For example, the "L" field can be set to "2", indicating that a two-byte data field is used for the frame identifier. ■The frame identifier identifies a frame corresponding to the data packet in a predefined number of consecutive frames and is incremented for each predefined number of consecutive different frames. For example, the frame identifier of each frame may be the frame SN of the frame. The predefined number of frame SNs is 65536. ■For each data packet of the same frame, the frame identifier is the same. Packet Dropped:

[0083] XR services are time-sensitive, and each data packet corresponding to a frame should arrive at the client of the XR application within the required time delay. If a data packet is no longer useful to the decoder (or decompressor) of the XR receiver (e.g., the UE 10 or the XR server 41) because the decoding / decompression operation in the decoder (or the decompressor) has moved to multiple data packets of the subsequent frame, then the data packet is an obsolete data packet and can be discarded as soon as possible. In other words, transmitting obsolete data packets is unnecessary and inefficient, and may waste network capacity of the Radio Access Network (RAN) or the Core Network (CN).

[0084] refer to Fig.18, the transmitter device performs an embodiment of the disclosed method, discarding outdated data packets (e.g., data packets 411 and 414) based on a timer and a transmission window. The timer and the transmission window are refreshed for each frame of the XR stream of the XR service. In one embodiment, the timer is represented as t_frame_transmission, configured to time the transmission window in the time domain, the transmission window has a window size represented as Window_size, and is bounded by a minimum frame SN Minimum_frame_SN and a maximum frame SN obtained from Minimum_frame_SN+Window_size. That is, the transmission window is a range defined by the minimum frame SN Minimum_frame_SN and the maximum frame SN. The maximum frame SN is determined by the minimum frame SN and a predefined window size of the transmission window. The transmission window slides when the timer expires, by adding one or a predefined value to the minimum frame SN to form a new minimum frame SN value of the transmission window. When the sender device processes the XR stream of the XR service, in the frame of the sender device, the data packets of the corresponding frame that arrive at the packet discard layer (e.g., the PDCP layer or the SDAP layer) within the transmission window of the corresponding frame (e.g., data packets 412 or 413) are data packets that meet the delay requirement of the XR service, and the data packets of the corresponding frame that arrive at the packet discard layer outside the transmission window of the corresponding frame (e.g., data packets 411 or 414) are outdated data packets that do not meet the delay requirement of the XR service.

[0085] In one embodiment, the frame identifier is a frame SN. The packet identifier includes the frame SN of the corresponding frame. If the frame SN is within the range defined by the minimum frame SN and the maximum frame SN, the packet of the corresponding frame is within the transmission window of the corresponding frame. If the frame SN is not within the range defined by the minimum frame SN and the maximum frame SN, the packet is not within the transmission window of the corresponding frame. When the packet identifier of the packet is within the transmission window of the corresponding frame, the packet discard layer passes the packet to a lower layer (e.g., an RLC layer). When the packet identifier of the packet is not within the transmission window range of the corresponding frame, the packet discard layer discards the packet. An embodiment of the disclosed method may be embodied as the following algorithm: ●When configuring the RLC entity for XR services, ■Configure the Window_size of the transmission window for each XR stream; ■Configure a timer t_frame_transmission for each XR stream and reset it for each frame of the XR stream; ● In the RLC entity, each service data unit (SDU) received from the upper layer includes a data packet of a frame of the XR stream, and the data packet carries the frame SN of the data packet. ● When the RLC entity receives an SDU, ■ If the timer t_frame_transmission is not running, ◆ Start the timer t_frame_transmission and set the minimum frame SN Minimum_frame_SN to the frame SN. ■ Otherwise ◆ If the frame SN < Minimum_frame_SN or the frame SN >= (Minimum_frame_SN + Window_size), ● Discard the SDU. ◆ Otherwise ● Pass the PDU corresponding to the SDU to the lower layer. ● If the timer t_frame_transmission has expired, ■ Set Minimum_frame_SN to Minimum_frame_SN + 1; ■ Reset and restart the timer t_frame_transmission;

[0086] The timer t_frame_transmission can be configured as an integer multiple of the frame period. The frame SN information of the data packet in each SDU can be received from the PDCP layer in the form of an inter-layer service or an SDU header. For example, in one embodiment, the RLC layer synchronously receives the frame SN information of each SDU from the PDCP layer. In another embodiment, the RLC layer obtains and removes the frame SN information from the SDU header, and obtains the remaining part of the SDU as the final SDU of the RLC entity.

[0087] In another embodiment, the timer t_frame_transmission can be set to one of two values, t1 and t2. t1 is configured for the first frame, and t2 is configured for other frames. Generally, t1 is greater than t2. Each of t1 and t2 can be configured as an integer multiple of the frame period.

[0088] For the configuration of Window_size and timer t_frame_transmission, the gNB 20 may obtain the configuration information of Window_size and timer t_frame_transmission from a radio resource control (RRC) message or a medium access control (MAC) control element (CE) of the UE through an NR Uu interface, or obtain it from an NG application protocol (NGAP) message of an access and mobility management function (AMF) through an NG interface, such as Fig.19 shown.

[0089] The transmitter device may determine the configuration of Window_size and t_frame_transmission based on the quality of service (QoS) requirements and / or characteristics of the XR service and one or more parameters of XR client capabilities. The XR client capability parameters represent various capabilities of one or more XR clients (such as the transmitter device and / or the receiver device). In one embodiment, the parameters may include, but are not limited to, one or more of the following parameters related to the XR service: QoS requirement parameters; ●Flow characteristic parameters; and ●XR client capability parameters.

[0090] QoS requirement parameters include one or more of the following: Packet Delay Budget (PDB); Packet Error Rate (PER); Packet loss rate (PLR); Frame error rate; and ●Frame delay budget.

[0091] Traffic characteristic parameters include one or more of the following: ● Resolution; Frame rate ● frame size; and ●Data rate.

[0092] XR client capability parameters include one or more of the following: ●The XR client’s buffering capability for the XR service.

[0093] Fig. 20 7 is a block diagram of an exemplary system 700 for wireless communication according to one embodiment of the present disclosure. The embodiments described herein may be implemented into the system using any suitably configured hardware and / or software. Fig. 20The system 700 is shown, including radio frequency (RF) circuitry 710, baseband circuitry 720, processing unit 730, memory / storage 740, display 750, camera 760, sensor 770, and input / output (I / O) interface 780, which are coupled to each other as shown.

[0094] The processing unit 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 and an application processor. The processor may be coupled to the memory / storage and configured to execute instructions stored in the memory / storage to enable various applications and / or operating systems running on the system.

[0095] The radio control functions may include, but are not limited to, signal modulation, encoding, decoding, radio frequency shifting, etc. In some embodiments, the baseband circuitry may provide communications compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry may support communications with the fifth generation new radio (5G NR), long term evolution (LTE), evolved universal terrestrial radio access network (EUTRAN) and / or other wireless metropolitan area networks (WMANs), wireless local area networks (WLANs), wireless personal area networks (WPANs). An embodiment configured to support radio communications of more than one wireless protocol may be referred to as a multi-mode baseband circuit. In various embodiments, the baseband circuitry 720 may include circuitry for operating signals that are not strictly considered to be baseband frequencies. For example, in some embodiments, the baseband circuitry may include circuitry for operating signals having an intermediate frequency that is between the baseband frequency and the radio frequency.

[0096] In various embodiments, the system 700 may be a mobile computing device, such as, but not limited to, a laptop, a tablet, a netbook, an ultrabook, a smartphone, etc. In various embodiments, the system may have more or fewer components, and / or a different architecture. Where appropriate, the methods described herein may be implemented as a computer program. The computer program may be stored on a storage medium, such as a non-transient storage medium.

[0097] The embodiments of the present disclosure are a combination of techniques / processes that can be adopted in the 3GPP specifications to create a final product.

[0098] If the software functional unit is implemented, used and sold as a product, it can be stored in a readable storage medium in a computer. Based on this understanding, the technical solution proposed in the present disclosure can be implemented basically or partially in the form of a software product. Alternatively, a part of the technical solution that is beneficial to traditional technology can be implemented in the form of a software product. The software product in the computer is stored in a storage medium, including multiple commands that enable a computing device (such as a personal computer, a server or a network device) to run all or part of the steps disclosed in the embodiments of the present disclosure. The storage medium includes a USB disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a floppy disk or other media capable of storing program code.

[0099] In an embodiment of the present disclosure, video frames of the XR service may be periodically segmented into one or more data packets for transmission over the network.

[0100] Embodiments of the present invention provide: ●A method of identifying multiple packets of a frame in a transmission network. ●A method for extending a data packet identifier of a transmission frame based on the Real-time Transport Protocol (RTP) protocol and the RTP header. ●A method for discarding outdated packets of a frame based on a timer, a transmission window, and an identifier that identifies the frame.

[0101] While the present disclosure has been described in connection with what are considered to be the most practical and preferred embodiments, it is to be understood that the present disclosure is not limited to the disclosed embodiments but is intended to cover various arrangements made without departing from the broadest interpretation of the appended claims.

Claims

1. A wireless communication method, which may be performed in a wireless communication device operating as a transmitter device, comprising: Receive multiple data packets of corresponding frames in an XR stream of an extended reality XR service, wherein each of the multiple data packets of the corresponding frame includes a protocol data unit (PDU) header carrying a data packet identifier of the data packet; configuring the transmission window based on the corresponding frame of the XR stream and a timer of the transmission window; Determining whether to discard a data packet associated with the data packet identifier based on the data packet identifier; When the data packet identifier of the data packet is within the transmission window of the corresponding frame, delivering the data packet to a lower layer; and When the data packet identifier of the data packet exceeds the transmission window of the corresponding frame, the data packet is discarded.

2. The method of claim 1 , wherein the packet identifier comprises at least one of a frame identifier or a packet identifier, wherein the frame identifier identifies the corresponding frame of the plurality of packets among a predetermined number of consecutive different frames of the XR stream, and the packet identifier identifies the packet among a plurality of packets of the corresponding frame.

3. The method of claim 2, wherein the frame identifier is a frame sequence number SN, which is incremented for each frame in the predetermined number of consecutive different frames.

4. The method of claim 2, wherein in an identifier insertion layer, the packet identification is inserted into a protocol data unit (PDU) header of each of a plurality of packets of the corresponding frame.

5. The method of claim 2, wherein the data packet identifier is inserted into a header extension of a real-time transport protocol (RTP) header in the PDU header.

6. The method of claim 5, wherein the field "X" in the RTP header is set to "1" to indicate that there are one or more header extensions in the RTP header that carry the data packet identifier.

7. The method of claim 6, wherein the packet identifier includes only the frame identifier.

8. The method of claim 6, wherein the packet identifier comprises the frame identifier and the packet identifier.

9. The method of claim 1, wherein the transmission window is configured for the XR stream, and the transmission window is defined by a minimum frame sequence number SN and a maximum frame sequence number SN.

10. The method of claim 9, wherein the data packet identifier comprises a frame SN of the corresponding frame, and if the frame SN is within the range defined by the minimum frame SN and the maximum frame SN, the data packet is within the transmission window of the corresponding frame; if the frame SN is not within the range defined by the minimum frame SN and the maximum frame SN, the data packet is not within the transmission window of the corresponding frame.

11. The method of claim 9, wherein the maximum frame SN is determined by the minimum frame SN and a predefined window size of the transmission window.

12. The method of claim 1 or 9, wherein when the timer expires, the transmission window is slid by adding 1 or a predefined value to the minimum frame SN to form a new minimum frame SN value of the transmission window.

13. The method of claim 9, wherein the window size of the transmission window and the timer are determined based on one or more of the following: Quality of Service (QoS) requirement parameters of the XR service; Traffic characteristic parameters of the XR service; and XR client capability parameters of the XR service.

14. The method of claim 13, wherein the window size and the configuration information of the timer are transmitted in a radio resource control RRC message or a media access control MAC control element CE via an NR Uu interface, or are transmitted in a NG application protocol NGAP message from an access and mobility management function AMF via an NG interface.

15. The method of claim 13, wherein the QoS requirement parameters of the XR service include one or more of the following: Packet Delay Budget (PDB); Packet Error Rate (PER); Packet Loss Rate (PLR); Frame Error Rate; and Frame delay budget.

16. The method of claim 13, wherein the flow characteristic parameters include one or more of the following: Resolution; Frame rate; frame size; and Data rate.

17. The method of claim 13, wherein the XR client capability parameters include one or more of the following: The buffering capabilities of the XR client of the XR service.

18. The method of claim 1, further comprising: The data packet identifier is obtained and removed from the PDU header of the data packet.

19. The method of claim 18, wherein inserting the packet identifier into the PDU header of each of the plurality of packets of the corresponding frame is performed in an identifier insertion layer of a source point of the XR stream of the XR service; Obtaining and removing the data packet identifier from the PDU header of the data packet is performed in the header processing layer of the transmitter device; Determining whether to discard a data packet associated with the data packet identifier, delivering the data packet, and discarding the data packet are performed in a data packet discard layer of the transmitter device.

20. The method of claim 19, wherein the header processing layer comprises a Packet Data Convergence Protocol (PDCP) layer or a Service Data Adaptation Protocol (SDAP) layer of the transmitter device.

21. The method of claim 19, wherein the packet discard layer comprises a Packet Data Convergence Protocol (PDCP) layer or a Radio Link Control (RLC) layer of the sender device.

22. A wireless communication device, comprising: A processor configured to call and run a computer program stored in a memory so that a device equipped with the processor executes the method described in any one of claims 1 to 21.

23. A chip, comprising: 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 as described in any one of claims 1 to 21.

24. A computer-readable storage medium storing a computer program, wherein the computer program enables a computer to execute the method according to any one of claims 1 to 21.

25. A computer program product comprising a computer program, wherein the computer program causes a computer to execute the method according to any one of claims 1 to 21.

26. A computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 21.

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