Protocol data unit set dependency and data burst dependency awareness

Abstract

This disclosure provides systems, devices, apparatus, and methods, including computer programs encoded on storage media, for PDU set dependency awareness. A first wireless communication device transmits (810), to a second wireless communication device, an indication of a dependency between first protocol data unit, PDU, Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group. The first device transmits (830), to the second device, the first PDU Set or the first Data Burst.

Description

PROTOCOL DATA UNIT SET DEPENDENCY AND DATA BURST DEPENDENCY AWARENESSTECHNICAL FIELD

[0001] The present disclosure relates generally to wireless communication, and more particularly, to protocol data unit (PDU) Set dependency awareness and Data Burst dependency awareness.BACKGROUND

[0002] The Third Generation Partnership Project (3GPP) specifies a radio interface referred to as fifth generation (5G) new radio (NR) (5G NR). An architecture for a 5G NR wireless communication system (5GS) includes a 5G core (5GC) network, a 5G radio access network (5G- RAN), a user equipment (5G UE), etc. The 5G NR architecture seeks to provide increased data rates, decreased latency, and / or increased capacity compared to prior generation cellular communication systems.

[0003] Wireless communication systems, in general, provide various telecommunication services (e.g., telephony, video, data, messaging, etc.) based on multiple-access technologies, such as orthogonal frequency division multiple access (OFDMA) technologies, that support communication with multiple UEs. Improvements in mobile broadband continue the progression of such wireless communication technologies.

[0004] A dependent protocol data unit (PDU) Set depends on the data in a reference PDU Set for correct rendering. Similarly, a dependent Data Burst depends on the data in a reference Data Burst for correct rendering. In some implementations, a user equipment (UE) or network entity cannot decode dependent PDU Sets or dependent Data Bursts (e.g., P-frame video data) without first decoding a reference PDU Set or reference Data Burst (e.g., I-frame video data). If the UE or the network entity does not correctly receive and decode the reference PDU Set or reference Data Burst, subsequent transmission of dependent PDU Sets or Data Bursts use network resources but do not provide much benefit at the receiver.BRIEF SUMMARY

[0005] The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects. This summary neither identifies key or critical elements of all aspects nor delineates the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0006] A user equipment (UE) or network entity (e.g., base station, unit of a base station, core network entity, etc.) communicates video data organized into protocol data unit (PDU) Sets and / or Data Bursts. A PDU Set includes one or more PDUs carrying a pay load of one unit of information generated at the application level (e.g., a video frame or video slice). A PDU Set group includes multiple PDU Sets (e.g., multiple video frames and / or multiple video slices). A Data Burst is a set of multiple PDUs generated and sent by the application in a short period of time. A Data Burst includes one or multiple PDU Sets. A Data Burst group includes multiple Data Bursts.

[0007] To address network inefficiency due to subsequent transmission of dependent PDU Sets or dependent Data Bursts after unsuccessful receipt of a reference PDU Set or reference Data Burst, the UE or network entity implements network control techniques that utilize inter-PDU Set dependency awareness and additional controls (e.g., packet data convergence protocol (PDCP) discard timer, PDU Set importance (PSI), and downgrading of radio bearers). These network control techniques apply to both the instantaneous decoding refresh model and the gradual decoding refresh model for the decoding of video frames. For example, a UE transmits to a network entity (or a network entity transmits to a UE) an indication of the dependency among PDU Sets within a PDU Set group or the dependency among Data Bursts within a Data Burst group. In one example, dependent PDU Sets or dependent Data Bursts include a sequence number pointing to the reference PDU Set or reference Data Burst required for correct rendering of the dependent PDU Sets or dependent Data Bursts.

[0008] When the UE or network entity transmits a PDU Set or Data Burst, the transmitting entity waits for a positive acknowledgement (ACK) to indicate that the PDU Set or Data Burst was correctly decoded at the receiving entity. If the UE or network entity does not receive a successful delivery confirmation (e.g., hybrid automatic repeat request (HARQ) acknowledgement (ACK)) by lower layers (e.g., medium access control (MAC) layer) before expiration of a timer (e.g., a PDCP discard timer), the UE or network entity determines the PDU Set or Data Burst was not correctly decoded. The PDCP discard time period is extended for reference PDU Sets or reference Data Bursts as compared to dependent PDU Sets or dependent Data Bursts due to the higher importance (e.g., higher PSI) of the reference PDU Sets or reference Data Bursts. In some aspects, when the reference PDU Set or reference Data Burst is not correctly decoded by the receiving entity, the transmitting entity (e.g., UE or network entity) discards the remaining PDU Set(s) within the PDU Set group or the remaining Data Burst(s) within the Data Burst group. In some aspects, the UE or network entity transmits a second reference PDU Set or second reference Data Burst. The second reference PDU Set or second reference Data Burst may be a retransmission of the first reference PDU Set or first reference Data Burst. In some aspects, the second reference PDU Set or second reference Data Burst may be a different reference PDUSet or different Data Burst. Alternatively, the UE or network entity downgrades a radio bearer of the remaining PDU Set(s) within the PDU Set group or downgrades a radio bearer of the remaining Data Burst(s) within the Data Burst group. Since the decoding of the remaining PDU Set(s) / Data Burst(s) are dependent on the reference PDU Set / Data Burst and cannot be decoded without the reference PDU Set / Data Burst, discarding or downgrading the remaining PDU Set(s) / Data Burst(s) reduces network inefficiency.

[0009] In some aspects, the UE or network entity may receive the indication of dependency between PDU Sets or Data Bursts from an application layer or video coder-decoder (codec). For example, an extended reality (XR) application or video codec executing on the UE provides to lower layers (e.g., PDCP layer) the dependency between PDU Sets within a PDU Set group or the dependency between Data Bursts within a Data Burst group. At the network side, as another example, an XR application server or codec provides the network entity (e g., generation Node B (gNB), base station, central unit (CU), distributed unit (DU), radio unit (RU), etc.) with the dependency between the PDU Sets or the dependency between Data Bursts via a general packet radio service tunneling protocol user plane (GTP-U) header, a real-time transport protocol (RTP) header, or control plane signaling. The network entity transmits the indication of PDU Set / Data Burst dependency to the UE when a network congestion level nears or exceeds a threshold. The UE begins discarding / downgrading dependent PDU Set(s) / Data Burst(s) when the UE receives the PDU Set / Data Burst dependency indication.

[0010] According to some aspects, a UE transmits to a network entity (or a network entity transmits to a UE), an indication of a dependency between PDU Sets within a PDU Set group or a dependency between Data Bursts within a Data Burst group. The UE transmits to the network entity (or the network entity transmits to the UE) a first PDU Set or a first Data Burst.

[0011] Technical benefits of the present disclosure include reducing network traffic because the UE and network entity discard dependent PDU Set(s) / Data Burst(s) when a reference PDU Set within a PDU Set group or a reference Data Burst within a Data Burst group is not correctly decoded. Further benefits include the network entity and / or the UE controlling the discarding of dependent PDU Set(s) / Data Burst(s) using the examples described with reference to FIGs. 2-15.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 illustrates a diagram of a wireless communications system that includes a plurality of user equipments (UEs) and network entities in communication over one or more cells according to an embodiment.

[0013] FIG. 2 illustrates a diagram of a wireless communications system that includes a plurality of UEs and a network entity in communication over access links according to an embodiment.

[0014] FIG. 3 illustrates a diagram of the dependency between video slices in an I-frame and video slices in P-frames according to an embodiment.

[0015] FIG. 4A illustrates a diagram of protocol data unit (PDU) Set groups in a gradual decoding refresh model according to an embodiment.

[0016] FIG. 4B illustrates a diagram of PDU Set groups in an instantaneous decoding refresh model according to an embodiment.

[0017] FIG. 5 illustrates a timing diagram of video frames and a dependency between reference PDU Sets and dependent PDU Sets according to an embodiment.

[0018] FIG. 6 illustrates a timing diagram of video frames and a dependency between reference Data Bursts and dependent Data Bursts according to an embodiment.

[0019] FIG. 7A illustrates a dependency indication table for reference PDU Sets and dependent PDU Sets using the gradual decoding refresh model according to an embodiment.

[0020] FIG. 7B illustrates a dependency indication table for reference Data Bursts and dependent Data Bursts using the gradual decoding refresh model according to an embodiment.

[0021] FIG. 7C illustrates a dependency indication table for reference PDU Sets and dependent PDU Sets using the instantaneous decoding refresh model according to an embodiment.

[0022] FIG. 7D illustrates a dependency indication table for reference Data Bursts and dependent Data Bursts using the instantaneous decoding refresh model according to an embodiment.

[0023] FIG. 8 is a signaling diagram illustrating communications between a UE and a network entity for PDU Set / Data Burst interdependency and discarding by a UE according to an embodiment.

[0024] FIG. 9 is a signaling diagram illustrating communications between a UE and a network entity for PDU Set / Data Burst interdependency and discarding by a network entity according to an embodiment.

[0025] FIG. 10 is a flowchart of a method of PDU Set / Data Burst interdependency and discarding at a UE according to an embodiment.

[0026] FIG. 11 is a flowchart of a method of PDU Set / Data Burst interdependency and discarding at a network entity according to an embodiment.

[0027] FIG. 12 is a flowchart of a method of wireless communication at a UE according to another embodiment.

[0028] FIG. 13 is a flowchart of a method of wireless communication at a network entity according to another embodiment.

[0029] FIG. 14 is a diagram illustrating a hardware implementation for an example UE apparatus according to some embodiments.

[0030] FIG. 15 is a diagram illustrating a hardware implementation for one or more example network entities according to some embodiments.

[0031] In FIGs. 1-15 like reference numbers refer to like actions.DETAILED DESCRIPTION

[0032] FIG. 1 illustrates a diagram 100 of a wireless communications system associated with a plurality of cells 190. The wireless communications system includes user equipments (UEs) 102 and base stations / network entities 104. Some base stations may include an aggregated base station architecture and other base stations may include a disaggregated base station architecture. The aggregated base station architecture utilizes a radio protocol stack that is physically or logically integrated within a single radio access network (RAN) node. A disaggregated base station architecture utilizes a protocol stack that is physically or logically distributed among two or more units (e.g., radio unit (RU) 106, distributed unit (DU) 108, central unit (CU) 110). For example, a CU 110 is implemented within a RAN node, and one or more DUs 108 may be co-located with the CU 110, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes. The DUs 108 may be implemented to communicate with one or more RUs 106. Any of the RU 106, the DU 108 and the CU 110 can be implemented as virtual units, such as a virtual radio unit (VRU), a virtual distributed unit (VDU), or a virtual central unit (VCU). The base station / network entity 104 (e.g., an aggregated base station or disaggregated units of the base station, such as the RU 106 or the DU 108), may be referred to as a transmission reception point (TRP).

[0033] Operations of the base station 104 and / or network designs may be based on aggregation characteristics of base station functionality. For example, disaggregated base station architectures are utilized in an integrated access backhaul (IAB) network, an open-radio access network (O-RAN) network, or a virtualized radio access network (vRAN), which may also be referred to a cloud radio access network (C-RAN). Disaggregation may include distributing functionality across the two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network designs. The various units of the disaggregated base station architecture, or the disaggregated RAN architecture, can be configured for wired or wireless communication with at least one other unit. For example, the base stations 104d, 104e and / or the RUs 106a, 106b, 106c, 106d may communicate with the UEs 102a, 102b, 102c, 102d, and / or 102s via one or more radio frequency (RF) access links based on a Uu interface. In examples, multiple RUs 106 and / or base stations 104 may simultaneously serve the UEs 102, such as by intra-cell and / or inter-cell access links between the UEs 102 and the RUs 106 / base stations 104.

[0034] The RU 106, the DU 108, and the CU 110 may include (or may be coupled to) one or more interfaces configured to transmit or receive information / signals via a wired or wireless transmission medium. For example, a wired interface can be configured to transmit or receive the information / signals over a wired transmission medium, such as viathe fronthaul link 160 between the RU 106d and the baseband unit (BBU) 112 of the base station 104d associated with the cell 190d. The BBU 112 includes a DU 108 and a CU 110, which may also have a wired interface (e.g., midhaul link) configured between the DU 108 and the CU 110 to transmit or receive the information / signals between the DU 108 and the CU 110. In further examples, awireless interface, which may include a receiver, a transmitter, or a transceiver, such as an RF transceiver, configured to transmit and / or receive the information / signals via the wireless transmission medium, such as for information communicated between the RU 106a of the cell 190a and the base station 104e of the cell 190e via cross-cell communication beams 136-138 of the RU 106a and the base station 104e.

[0035] The RUs 106 may be configured to implement lower layer functionality. For example, the RU 106 is controlled by the DU 108 and may correspond to a logical node that hosts RF processing functions, or lower layer PHY functionality, such as execution of fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc. The functionality of the RU 106 may be based on the functional split, such as a functional split of lower layers.

[0036] The RUs 106 may transmit or receive over-the-air (OTA) communication with one or more UEs 102. For example, the RU 106b of the cell 190b communicates with the UE 102b of the cell 190b via a first set of communication beams 132 of the RU 106b and a second set of communication beams 134b of the UE 102b, which may correspond to inter-cell communication beams or, in some examples, cross-cell communication beams. For instance, the UE 102b of the cell 190b may communicate with the RU 106a of the cell 190a via a third set of communication beams 134a of the UE 102b and a fourth set of communication beams 136 of the RU 106a. DUs 108 can control both real-time and non-real-time features of control plane and user plane communications of the RUs 106.

[0037] Any combination of the RU 106, the DU 108, and the CU 110, or reference thereto individually, may correspond to a base station 104. Thus, the base station 104 may include at least one of the RU 106, the DU 108, or the CU 110. The base stations 104 provide the UEs 102 with access to a core network 120. The base stations 104 may relay communications between the UEs 102 and the core network 120. The base stations 104 may be associated with macrocells for higher- power cellular base stations and / or small cells for lower-power cellular base stations. For example, the cell 190emay correspond to a macrocell, whereas the cells 190a-190d may correspond to smallcells. Small cells include femtocells, picocells, microcells, etc. A network that includes at least one macrocell and at least one small cell may be referred to as a “heterogeneous network.” One or more CUs 110 may communicate directly with a core network 120 via a backhaul link. For example, the CU 110 communicates with the core network 120 over a backhaul link based on a next generation (NG) interface. The one or more CUs 110 may also communicate indirectly with the core network 120 through one or more disaggregated base station units, such as a near-real time RAN intelligent controller (R1C) via an E2 link and a service management and orchestration (SMO) framework, which may be associated with a non-real time RIC.

[0038] Transmissions from a UE 102 to a base station 104 / RU 106 are referred to as uplink (UL) transmissions, whereas transmissions from the base station 104 / RU 106 to the UE 102 are referred to as downlink (DL) transmissions. Uplink transmissions may also be referred to as reverse link transmissions and downlink transmissions may also be referred to as forward link transmissions. For example, the RU 106d utilizes antennas of the base station 104d of cell 190d to transmit a downlink / forward link communication to the UE 102d or receive an uplink / reverse link communication from the UE 102d based on the Uu interface associated with the access link between the UE 102d and the base station 104d / RU 106d.

[0039] Communication links between the UEs 102 and the base stations 104 / RUs 106 may be based on multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication links may be associated with one or more carriers. The UEs 102 and the base stations 104 / RUs 106 may utilize a spectrum bandwidth of F MHz (e g., 5, 10, 15, 20, 100, 400, 800, 1600, 2000, etc. MEIz) per carrier allocated in a carrier aggregation of up to a total of Yx MHz, where x component carriers (CCs) are used for communication in each of the uplink and downlink directions. The carriers may or may not be adjacent to each other along a frequency spectrum. In examples, uplink and downlink carriers may be allocated in an asymmetric manner, with more or fewer carriers allocated to either the uplink or the downlink. A primary component carrier and one or more secondary component carriers may be included in the component carriers. The primary component carrier may be associated with a primary cell (PCell) and a secondary component carrier may be associated with a secondary cell (S Cell).

[0040] Some UEs 102, such as the UEs 102a and 102s, may perform device-to-device (D2D) communications over sidelink. For example, a sidelink communication / D2D link utilizes a spectrum for a wireless wide area network (WWAN) associated with uplink and downlink communications. Such sidelink / D2D communication may be performed through various wireless communications systems, such as wireless fidelity (Wi-Fi) systems, Bluetooth systems, Long Term Evolution (LTE) systems, New Radio (NR) systems, etc.

[0041] The UEs 102 and the base stations 104 / RUs 106 may each include a plurality of antennas. The plurality of antennas may correspond to antenna elements, antenna panels, and / or antenna arrays that may facilitate beamforming operations. For example, the RU 106b transmits a downlink beamformed signal based on a first set of communication beams 132 to the UE 102b in one or more transmit directions of the RU 106b. The UE 102b may receive the downlink beamformed signal based on a second set of communication beams 134b from the RU 106b in one or more receive directions of the UE 102b. In a further example, the UE 102b may also transmit an uplink beamformed signal (e.g., sounding reference signal (SRS)) to the RU 106b based on the second set of communication beams 134b in one or more transmit directions of the UE 102b. The RU 106b may receive the uplink beamformed signal from the UE 102b in one or more receive directions of the RU 106b. The UE 102b may perform beam training to determine the best receive and transmit directions for the beamformed signals. The transmit and receive directions for the UEs 102 and the base stations 104 / RUs 106 may or may not be the same.

[0042] In further examples, beamformed signals may be communicated between a first base station / RU 106a and a second base station 104e. For instance, the base station 104e of the cell 190e may transmit a beamformed signal to the RU 106a based on the communication beams 138 in one or more transmit directions of the base station 104e. The RU 106a may receive the beamformed signal from the base station 104e of the cell 190e based on the RU communication beams 136 in one or more receive directions of the RU 106a. In further examples, the base station 104e transmits a downlink beamformed signal to the UE 102e based on the communication beams 138 in one or more transmit directions of the base station 104e The UE 102e receives the downlink beamformed signal from the base station 104e based on UE communication beams 130 in one or more receive directions of the UE 102e. The UE 102e may also transmit an uplink beamformed signal to the base station 104e based on the UE communication beams 130 in one or more transmit directions of the UE 102e, such that the base station 104e may receive the uplink beamformed signal from the UE 102e in one or more receive directions of the base station 104e.

[0043] The base station 104 may include and / or be referred to as a network entity. That is, “network entity” may refer to the base station 104 or at least one unit of the base station 104, such as the RU 106, the DU 108, and / or the CU 110. The base station 104 may also include and / or be referred to as a next generation evolved Node B (ng-eNB), a next generation NB (gNB), an evolved NB (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), aTRP, a network node, network equipment, or other related terminology. The base station 104 or an entity at the base station 104 can be implemented as an IAB node, a relay node, a sidelink node, an aggregated (monolithic) base station, or a disaggregated base station including one or moreRUs 106, DUs 108, and / or CUs 110. A set of aggregated or disaggregated base stations may be referred to as a next generation-radio access network (NG-RAN). In some examples, the UE 102a operates in dual connectivity (DC) with the base station 104e and the base station / RU 106a. In such cases, the base station 104e can be a master node and the base station / RU 160a can be a secondary node.

[0044] Still referring to FIG. 1, in certain aspects, any of the UEs 102 may include a video data dependency component 140 configured to transmit, to a network entity, an indication of a dependency between a first protocol data unit (PDU) Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group. The video data dependency component 140 is further configured to transmit, to the network entity, the first PDU Set or the first Data Burst.

[0045] In certain aspects, any of the base stations 104 or a network entity of the base stations 104 may include a PDU Set / Data Burst dependency component 150 configured to transmit, to a UE, an indication of a dependency between a first PDU Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group. The PDU Set / Data Burst dependency component 150 is further configured to transmit, to the UE, the first PDU Set or the first Data Burst.

[0046] Accordingly, FIG. 1 describes a wireless communication system that may be implemented in connection with aspects of one or more other figures described herein. Further, although the following description may be focused on 5GNR, the concepts described herein may be applicable to other similar areas, such as 5G-Advanced and future versions, LTE, LTE- advanced (LTE-A), and other wireless technologies, such as 6G.

[0047] FIG. 2 illustrates a diagram of a wireless communications system 200 that includes a plurality of UEs 102 and a network entity 104 in communication over access links 250 (e.g., Uu access links). The network entity 104 communicates with the core network 120 over a backhaul link 252a (e g., Xn interface). The UEs 102 execute extended Reality (XR) applications (e.g., augmented reality (AR), virtual reality (VR), and / or mixed reality (MR)). In some aspects, the UEs 102 communicate video data associated with the XR application with XR server 121. The UEs 102 communicate the video data with the XR server 121 through network entity 104 and core network 120 using backhaul links 252a and 252b. In some aspects, XR device 101 (e.g., XR headset, XR glasses) executes an XR application and uses UE 102a as a hub / gateway to communicate with the XR server 121. For example, the XR application or the video codec is located in the XR device 101 and the modem is located in UE 102a. XR device 101 communicates with UE 102a using additional link 250c (e.g., a local network, Sidelink PC5, WiFi, universal serial bus (USB), etc.).

[0048] In some aspects, the XR device 101, UEs 102, network entity 104, core network 120, and XR server 121 communicate the video data as video frames / slices. The video frames / slices are designed to optimize the video codec compression efficiency. I-frames / slices are intra-coded frames / slices and are images or slices of an image that do not depend on any other frames / slices and encode an entire scene. P-frames / slices are predicted frames / slices that encode the changes with respect to the previous frames / slices. The previous frames / slices could be I-frames / slices or P-frames / slices. B-frames / shces are bi-directional frames / slices and are encoded with reference to previous frames / slices and to the next frames / slices. I-frames are more important to be delivered than a P-frame, because if an I-frame is missing at the decoder then dependent P-frames or B- frames that follow will not be decoded correctly and will not be useful.

[0049] Video frames are carried in Data Bursts. Video slices of a frame are carried by PDU Sets. A dependent PDU Set depends on the data in a reference PDU Set for correct rendering. Similarly, a dependent Data Burst depends on the data in a reference Data Burst for correct rendering. In some implementations, a UE 102 or network entity 104 cannot decode dependent PDU Sets or dependent Data Bursts (e.g., P-frame video data) without first decoding a reference PDU Set or reference Data Burst (e.g., I-frame video data). If the UE 102 or the network entity 104 does not correctly receive and decode the reference PDU Set or reference Data Burst, subsequent transmission of dependent PDU Sets or dependent Data Bursts use network resources but do not provide much benefit at the receiver.

[0050] To address network inefficiency due to subsequent transmission of dependent PDU Sets or Data Bursts after unsuccessful decoding of a reference PDU Set or reference Data Burst, the UE 102 or network entity 104 implements network control techniques that utilize inter PDU Set / Data Burst dependency awareness and additional controls (e.g., packet data convergence protocol (PDCP) discard timer, PDU Set importance (PSI), and downgrading of radio bearers). These network control techniques apply to both the instantaneous decoding refresh (IDR) model and the gradual decoding refresh (GDR) model for the decoding of video frames. In IDR model, P-frames contain only the changes in the image and rely on previous frames and mainly on the previous I-frame to be decoded. In the GDR model, the video frame is refreshed over a period of frames as there is an I-slice in each video frame. GDR allows for better random access as the refreshed area can be constructed properly when the decoding starts from any GDR frame and gradually covers the entire frame. In some aspects, the UE 102 transmits to the network entity 104 an indication of the dependency between PDU Sets within a PDU Set group or the dependency between Data Bursts within a Data Burst group. As another example, the network entity 104 transmits to the UE 102 an indication of the dependency between PDU Sets within a PDU Set group or the dependency between Data Bursts within a Data Burst group. In some aspects, thenetwork entity 104 receives the dependency information from XR server 121 (e.g., a video codec running on the XR server) via core network 120.

[0051] In some aspects, dependent PDU Sets or dependent Data Bursts include a sequence number pointing to the reference PDU Set or reference Data Burst required for correct rendering of the dependent PDU Sets or dependent Data Bursts as described with reference to FIGs. 7A-7D. The network control techniques that utilize inter-PDU Set dependency awareness are described with reference to FIGs. 3-13.

[0052] FIG. 3 illustrates a diagram 300 of the dependency between video slices 323 in an I- frame 321 and video slices 324 / 325 / 326 in P-frames 322 according to an embodiment. In the example of FIG. 3, slice 324a of P-frame 322a and slice 325a of P-frame 322b are dependent on slice 323a of I-frame 321. Correct decoding of slice 323a of I-frame 321 is required for correct subsequent rendenng of slice 324a of P-frame 322a, slice 325a of P-frame 322b, and slice 326a of P-frame 322c. Each of the video slices 323, 324, 325, and 326 are communicated via PDU Sets. Slice 324a of P-frame 322a, slice 325a of P-frame 322b, and slice 326a of P-frame 322c are considered dependent PDU Sets. Slice 323a of 1-frame 321 is considered a reference PDU Set. If the receiving entity (UE or network entity) does not correctly decode the reference PDU Set (I- frame slice), the transmitting entity discards the dependent PDU Sets since transmitting the dependent PDU Sets wastes network resources given that the dependent PDU sets cannot be decoded without successful decoding of the reference PDU set. Similarly, slice 324b of P-frame 322a, slice 325b of P-frame 322b, and slice 326b of P-frame 322c are dependent on slice 323b of 1-frame 321. Slice 324c of P-frame 322a, slice 325c of P-frame 322b, and slice 326c of P-frame 322c are dependent on slice 323c of 1-frame 321. Slice 324d of P-frame 322a, slice 325d of P- frame 322b, and slice 326d of P-frame 322c are dependent on slice 323d of 1-frame 321.

[0053] FIG. 4A illustrates a diagram 400 of PDU Set groups 424 configured for a gradual decoding refresh model according to an embodiment. PDU Set groups 424a-424f are each a group of PDU Sets including a reference PDU Set (I-frame slice) and dependent PDU Sets (P-frame slices). Each PDU set group 424 includes a reference PDU Set and all of its dependent PDU Sets. For example, referring to FIG. 4A, I-frame 321 slice #1 323a is the I-slice portion of 424a and P- frame 322 slices 324a, 325a are the P-slice portion of 424a. Similarly, the I-frame 321 slice #1 323b is the I-slice portion of 424b, and P-frame 322 slices 324b, 325b are the P-slice portions of 424b, etc. The I-frame slices are staggered across time (the x-axis) and each column of slices may form a single four-slice video frame. The dependent PDU Sets within a PDU Set group 424 that are transmitted within a frame (column) depend on the reference PDU Set within a previous frame (column) for correct rendering.

[0054] FIG. 4B illustrates a diagram 401 of PDU Set groups 425 configured for an instantaneous decoding refresh model according to an embodiment. PDU Set groups 425a-425d are each a group of PDU Sets including a reference PDU Set (I-frame slice) and dependent PDU Sets (P-frame slices). Each PDU set group 425 includes a reference PDU Set and all of its dependent PDU Sets. For example, referring to FIG. 4B, I-frame 321 slice #1 323a is the I-slice portion of 425a and the P-frame 322 slices 324a, 325a are the P-slice portion of 425a. Similarly, 1-frame 321 slice #1 323b is the I-slice portion of 425b, and P-frame 322 slices 324b, 325b are the P-slice portions of 425b, etc. In the IDR model, P-frames contain only the changes in the image and rely on one or more previous frames and mainly on the previous 1-frame to be rendered. The dependent PDU Sets within a PDU Set group 425 that are transmitted within a frame depend on the reference PDU Set within the same frame for correct rendering.

[0055] FIG. 5 illustrates a timing diagram 500 of video frames and a dependency between a reference PDU Set 550 and dependent PDU Sets 555 according to an embodiment. PDU Set group 424 is a group of PDU Sets including reference PDU Set 550 and dependent PDU Sets 555a and 555b. The dependent PDU Sets 555 depend on the reference PDU Set 550 in the PDU Set group 424 for rendenng. Each of the PDU Sets 550, 555 in the PDU set group 424 is associated with a different Data Burst 556 (e.g., different video frame). For example, PDU Set group 424 includes reference PDU Set 550 (I-frame slices) and two dependent PDU Sets 555a and 555b (P-frame slices). For example, referring to FIG. 4A, reference PDU Set 550 is the I-slice portion of 424a and PDU Sets 555a, 555b are the P-slice portions of 424a. Although the example of FIG. 5 describes PDU Set group 424 including two dependent PDU Sets 555, the present disclosure is not so limited and PDU Set group 424 may include any number of dependent PDU Sets 555. The reference PDU Set 550 is transmitted in a first Data Burst 556a within frame k. Dependent PDU Set 555a is scheduled to be transmitted in subsequent Data Burst 556b within frame k+1. Dependent PDU Set 555b is scheduled to be transmitted in subsequent Data Burst 556c wdthin frame k+2.

[0056] A UE transmits to a network entity (or a network entity transmits to a UE) an indication of the dependency betw een reference PDU Set 550 and dependent PDU Sets 555a and 555b within PDU Set group 424. As described further with reference to FIGs. 7A-7D, dependent PDU Sets 555 include a sequence number pointing to the reference PDU Set 550 required for correct rendering of the dependent PDU Sets 555.

[0057] When the UE or network entity transmits reference PDU Set 550, the transmitting entity waits for a successful delivery confirmation (e.g., hybrid automatic repeat request (HARQ) acknowledgement (ACK)) from lower layers (e g., medium access control (MAC) layer) to indicate that the reference PDU Set 550 was correctly decoded at the receiving entity. If the UEor network entity does not receive a successful delivery confirmation before expiration of a timer (e.g., a PDCP discard timer), the UE or network entity concludes the reference PDU Set 550 was not correctly decoded. In some implementations, the PDCP discard time period is extended for reference PDU Set 550 as compared to dependent PDU Sets 555 based on a higher importance (e.g., higher PSI) of the reference PDU Set 550. In some aspects, when reference PDU Set 550 is not correctly decoded by the receiving entity, the transmitting entity (e.g., UE or network entity) discards dependent PDU Sets 555 (as indicated by the X in FIG. 5) within PDU Set group 424. In some aspects, the UE or network entity transmits a second reference PDU Set. For example, the transmitting entity may receive a request and / or a trigger from the XR application and / or video codec to transmit the second reference PDU Set. The second reference PDU Set may be a retransmission of the first reference PDU Set 550. In some aspects, the second reference PDU Set may be a different reference PDU Set. Alternatively, the transmitting entity (e.g., UE or network entity) downgrades a radio bearer of the remaining PDU Sets 555 within PDU Set group 424. Since the decoding of the remaining dependent PDU Sets 555 are dependent on reference PDU Set 550 and cannot be rendered without reference PDU Set 550, discarding or downgrading a radio bearer of the remaining dependent PDU Sets 555 reduces network inefficiency.

[0058] FIG. 6 illustrates a timing diagram 600 of video frames and a dependency between a reference Data Burst 625 and dependent Data Bursts 626 according to an embodiment. FIG. 5 illustrates a dependency between a reference PDU Set 550 and dependent PDU Sets 555 while FIG. 6 illustrates a dependency between a reference Data Burst 625 and dependent Data Bursts 626. Data Burst group 624 is a group of Data Bursts including reference Data Burst 625 and dependent Data Bursts 626a and 626b. The dependent Data Bursts 626 depend on reference Data Burst 625 in the Data Burst group 624 for correct rendering. Each of the Data Bursts 625, 626 in the Data Burst group 624 is associated with a different video frame (e.g., video frame k, k+1, or k+2). Data Burst group 624 includes reference Data Burst 625 in frame k including PDU Sets carrying I-frame slices and dependent Data Burst 626a in frame k+ 1 and dependent Data Burst 626b in frame k+2 including PDU Sets carrying P-frame slices. Although the example of FIG. 6 describes Data Burst group 624 including two dependent data bursts 626, the present disclosure is not so limited and Data Burst Group 624 may include any number of dependent Data Bursts 626. The reference Data Burst 625 is transmitted within frame k. Dependent Data Burst 626a is scheduled to be transmitted within subsequent frame k+1 and dependent Data Burst 626b is scheduled to be transmitted within frame k+2.

[0059] A UE transmits to a network entity (or a network entity transmits to a UE) an indication of the dependency between reference Data Burst 625 and dependent Data Bursts 626a and 626b. As described further with reference to FIGs. 7A-7D, dependent Data Bursts 626 includea sequence number pointing to the reference Data Burst 625 required for correct rendering of the dependent Data Bursts 626.

[0060] When the UE or network entity transmits reference Data Burst 625, the transmitting entity waits for a successful delivery confirmation (e.g., HARQ ACK from lower layers (e.g., MAC layer)) to indicate that the reference Data Burst 625 was correctly decoded by the receiving entity. If the UE ornetwork entity does not receive a successful delivery confirmation (e.g., HARQ ACK) from lower layers before expiration of a timer (e.g., a PDCP discard timer), the UE or network entity concludes the reference Data Burst 625 was not correctly decoded. In some implementations, the PDCP discard time period is extended for a reference Data Burst 625 as compared to dependent Data Bursts 626 based on a higher importance (e.g., higher PSI) of the reference Data Burst 625. In some aspects, when reference Data Burst 625 is not correctly decoded by the receiving entity, the transmitting entity (e.g., UE or network entity) discards dependent Data Bursts 626 (as indicated by the X in FIG. 6) within Data Burst group 624. In some aspects, the UE or network entity transmits a second reference Data Burst. The second reference Data Burst may be a retransmission of the first reference Data Burst 625. In some aspects, the second reference Data Burst may be a different reference Data Burst. Alternatively, the transmitting entity (e.g. UE or network entity) downgrades a radio bearer of the remaining dependent Data Bursts 626 within Data Burst group 624. Since the rendering of the remaining dependent Data Bursts 626 are dependent on reference Data Burst 625 and cannot be properly rendered without correct decoding of reference Data Burst 625, discarding or downgrading a radio bearer of the remaining dependent Data Bursts 626 reduces network inefficiency. FIGs. 7A-7D described below are example indications of the dependency between reference PDU Sets / Data Bursts and dependent PDU Sets / Data Bursts described with reference to FIGs. 5 and 6.

[0061] FIG. 7A illustrates a dependency indication table 735 for reference PDU Sets and dependent PDU Sets using the gradual decoding refresh model according to an embodiment. The reference PDU Sets and dependent PDU Sets may be organized according to the descriptions of FIGs. 3 -5. A UE transmits to a network entity (or a network entity transmits to a UE) an indication of the dependency between reference PDU Sets and dependent PDU Sets based on sequence numbers of the PDU Sets. Dependency indication table 735 includes PDU Set groups 424a and 424b. Each of the dependent PDU Sets in PDU Set group 424a is assigned a sequence number indicated in the right column of table 735. A sequence number of the reference PDU Set that the dependent PDU Set depends upon is indicated in the left column. Similarly, each of the dependent PDU Sets in PDU Set group 424b (and other PDU Set groups in table 735) is assigned a sequence number indicated in the right column of table 735 and a sequence number of the reference PDU Set that the dependent PDU Set depends upon is indicated in the left column. In some aspects, theUE or network entity may receive the indication of dependency between PDU Sets from an application layer or video codec. For example, an XR application or video codec executing on the UE provides to lower layers (e.g., PDCP layer) the dependency between PDU Sets within PDU Set group 424. At the network side, as another example, an XR application server or codec provides the network entity (e g., gNB, BS, CU, DU, RU) with the dependency between the PDU Sets via a GTP-U header, a RTP header, or control plane signaling. Additionally or alternatively, the XR application or video codec may signal the dependency between video slices and / or between video frames to the transmitting entity. The transmitting entity may in turn convert the dependency between video slices and / or between video frames into the dependency between PDU Sets and / or the dependency between Data Bursts.

[0062] FIG. 7B illustrates a dependency indication table 736 for reference Data Bursts and dependent Data Bursts using the gradual decoding refresh model according to an embodiment. The reference Data Bursts and dependent Data Bursts may be organized according to the description of FIG 6. FIG. 7B illustrates a dependency indication table 736 structure similar to dependency indication table 735. A sequence number of the reference Data Burst that the dependent Data Bursts depend on is indicated in the left column. Each of the dependent Data Bursts in Data Burst group 624 (and other Data Burst groups in table 736) is assigned a sequence number indicated in the right column of table 736.

[0063] FIG. 7C illustrates a dependency indication table 737 for reference PDU Sets and dependent PDU Sets using the instantaneous decoding refresh model according to an embodiment. The reference PDU Sets and dependent PDU Sets may be organized according to the description of FIG 4B. FIG. 7C illustrates a similar dependency indication table 737 structure as dependency indication table 735. A sequence number of the reference PDU Set that the dependent PDU Sets depend upon is indicated in the left column. Each of the dependent PDU Sets in PDU Set group 424a (and other PDU Set groups in table 737) is assigned a sequence number indicated in the right column of table 737.

[0064] FIG. 7D illustrates a dependency indication table 738 for reference Data Bursts and dependent Data Bursts using the instantaneous decoding refresh model according to an embodiment. FIG. 7D illustrates a similar dependency indication table 738 structure as dependency indication table 735. A sequence number of the reference Data Burst that the dependent Data Bursts depend on is indicated in the left column. Each of the dependent Data Bursts in Data Burst group 624 (and other Data Burst groups in table 736) is assigned a sequence number indicated in the right column of table 738.

[0065] FIG. 8 is a signaling diagram 800 illustrating communications between a UE 102 and a network entity 104 for discarding / downgrading PDU Sets / Data Bursts according to anembodiment. In the example of FIG. 8, UE 102 is the PDU Set / Data Burst transmitting entity. A network entity 104 determines 805 a network congestion level. For example, network entity 104 determines whether a network congestion level nears or exceeds a threshold. The UE 102 and / or network entity 104 begin discarding / downgrading dependent PDU Sets / Data Bursts based on the network congestion level. Network entity 104 transmits 806 a PDCP discard timer configuration to the UE 102. The PDCP discard timer configuration indicates a time period(s) during which network entity 104 waits for confirmation from lower layers that the reference PDU Set or reference Data Burst has not been successfully delivered. The PDCP discard timer configuration may indicate the same PDCP discard timer period for reference PDU Sets / Data Bursts and dependent PDU Sets / Data Bursts. Alternatively, the PDCP discard timer configuration may indicate a longer PDCP discard timer period for reference PDU Sets / Data Bursts and a shorter PDCP discard timer period for dependent PDU Sets / Data Bursts. The PDCP discard time period is extended for reference PDU Sets or reference Data Bursts as compared to dependent PDU Sets or dependent Data Bursts due to the higher importance (e g., higher PSI) of the reference PDU Sets or Data Bursts.

[0066] The network entity 104 transmits 810, to the UE 102, an indication of PDU Set dependencies within PDU Set groups and / or Data Burst dependencies within Data Burst groups. For example, network entity 104 transmits 810 PDU Set dependency indication tables 735 and / or 737 to the UE 102 as described with reference to FIGs. 7A and 7C, respectively. Network entity 104 transmits 810 Data Burst dependency indication tables 736 and / or 738 to the UE 102 as described with reference to FIGs. 7B and 7D, respectively. The network entity 104 transmits 810 the indication of PDU Set / Data Burst dependency to the UE 102 when a network congestion level nears or exceeds a threshold. The UE 102 begins discarding / downgrading dependent PDU Set(s) / Data Burst(s) when the UE 102 receives 810 the PDU Set / Data Burst dependency indication. The UE 102 interprets the PDU Set / Data Burst dependency indication as a trigger to begin discarding / downgrading dependent PDU Set(s) / Data Burst(s).

[0067] In some aspects, the UE 102 receives an indication of dependency between PDU Sets / Data Bursts from an application layer or video codec. For example, an XR application or video codec executing on the UE 102 provides to lower layers of the UE 102 (e.g., PDCP layer) the dependency between PDU Sets within a PDU Set group or the dependency between Data Bursts within a Data Burst group. The UE 102 transmits 820, to network entity 104, the indication of PDU Set dependencies within PDU Set groups and / or Data Burst dependencies within Data Burst groups. For example, UE 102 transmits 820 PDU Set dependency indication tables 735 and / or 737 to the network entity 104 as described with reference to FIGs. 7A and 7C, respectively.UE 102 transmits 820 Data Burst dependency indication tables 736 and / or 738 to the network entity 104 as described with reference to FIGs. 7B and 7D, respectively.

[0068] The UE 102 transmits 830, to network entity 104, afirst PDU Set or a first Data Burst. The first PDU Set is a reference PDU Set. The first Data Burst is a reference Data Burst. The UE 102 starts the PCDP discard timer 850 when the first PDU Set or first Data Burst is received in the PDCP transmit buffer. If the UE 102 does not receive a successful delivery confirmation (e.g., ACK) assocrated wrth the first PDU Set or the first Data Burst from network entity 104 before the PDCP discard timer 850 expires, the UE 102 retransmits 860 the first PDU Set / first Data Burst, transmits a different PDU Set / Data Burst, discards 870 dependent Data Sets / Data Bursts, and / or downgrades 880 a radio bearer of dependent PDU Set(s) / Data Burst(s).

[0069] If the UE 102 receives 840 a confirmation from lower layers that the first PDU Set or first Data Burst has not been successfully delivered indicating the first PDU Set or first Data Burst was not correctly decoded by the network entity 104, the UE 102 retransmits 860 the first PDU Set / first Data Burst, transmits a different reference PDU Set / reference Data Burst, discards 870 dependent Data Sets / Data Bursts, or downgrades 880 a radio bearer of dependent PDU Set(s) / Data Burst(s). Since the rendering of the dependent PDU Set(s) / Data Burst(s) are dependent on the reference PDU Set / Data Burst, and the resulting frame (or slice) cannot be rendered properly without the reference PDU Set / Data Burst, discarding 870 or downgrading 880 the dependent PDU Set(s) / Data Burst(s) reduces network inefficiency.

[0070] FIG. 9 is a signaling diagram 900 illustrating communications between a UE 102 and a network entity 104 for discarding / downgrading PDU Sets / Data Bursts according to another embodiment. In FIG. 9, the network entity 104 is the PDU Set / Data Burst transmitting entity. Network entity 104 determines 805 a network congestion level. For example, the network entity 104 determines whether a network congestion level nears or exceeds a threshold. When the network congestion level nears or exceeds the threshold, the network entity 104 transmits 907 a congestion level indicator to core network 120. Core network 120 forwards the congestion level indicator to a video server (e.g., a codec on the video server) executing an application (e.g., XR application) in conjunction with the UE 102. The video server transmits an indication of PDU Set dependencies within PDU Set groups and / or Data Burst dependencies within Data Burst groups that are associated with the XR application to core network 120. Core network 120 transmits 908 the PDU Set / Data Burst dependencies to network entity' 104.

[0071] Network entity 104 transmits 806 a PDCP discard timer configuration and transmits 810 an indication of PDU Set dependencies within PDU Set groups and / or Data Burst dependencies within Data Burst groups as described with reference to FIG. 8 The UE 102 transmits 820, to the network entity 104, the indication of PDU Set dependencies within PDU Setgroups and / or Data Burst dependencies within Data Burst groups as described with reference to FIG. 8. Network entity 104 begins discarding / downgrading dependent PDU Set(s) / Data Burst(s) when network entity 104 receives 820 the PDU Set / Data Burst dependency indication.

[0072] In a manner that is the reverse of the uplink PDU Set or Data Burst shown in FIG. 8, the network entity 104 transmits 930, to UE 102, a first PDU Set or a first Data Burst. The first PDU Set is a reference PDU Set. The first Data Burst is a reference Data Burst. The network entity 104 starts the PCDP discard timer 950 when the first PDU Set or first Data Burst is received in the PDCP transmit buffer. If network entity 104 does not receive a successful delivery confirmation (e.g., an ACK) associated with the first PDU Set or the first Data Burst from UE 102 before the PDCP discard timer 950 expires, the network entity 104 retransmits 960 the first PDU Set / first Data Burst, transmits a different PDU Set / Data Burst, discards 970 dependent Data Sets / Data Bursts, and / or downgrades 980 a radio bearer of the first PDU Set / first Data Burst.

[0073] If the network entity 104 receives 940 a NACK from UE 102 indicating the first PDU Set or first Data Burst was not correctly decoded by the UE 102, the network entity 104 retransmits 960 the first PDU Set / first Data Burst, transmits a different reference PDU Set / reference Data Burst, discards 970 dependent Data Sets / Data Bursts, and / or downgrades 980 a radio bearer of the first PDU Set / first Data Burst.

[0074] Since the decoding of the dependent PDU Set(s) / Data Burst(s) are dependent on the reference PDU Set / Data Burst and cannot be rendered without the reference PDU Set / Data Burst, discarding 970 or downgrading 980 the dependent PDU Set(s) / Data Burst(s) reduces network inefficiency.

[0075] FIG. 10 illustrates a flowchart of a method 1000 of a UE performing PDU Set / Data Burst discarding / downgrading that relates to FIGs. 8-9, which illustrate signal flow diagrams showing options for PDU Set / Data Burst discarding / downgrading.

[0076] The UE receives 1006 a PDCP discard timer configuration from a network entity as described with reference to 806 in FIGs. 8-9.

[0077] The UE receives 1010, from the network entity, an indication of PDU Set dependency within PDU Set group(s) and / or a Data Burst dependency within Data Burst group(s) as described with reference to 810 in FIGs. 8-9.

[0078] The UE transmits 1020, to the network entity, an indication of PDU Set dependency within PDU Set group(s) and / or a Data Burst dependency within Data Burst group(s) as described with reference to 820 in FIGs. 8-9.

[0079] The UE transmits 1030, to the network entity, a first PDU Set or a first Data Burst as described with reference to 830 in FIG 8.

[0080] The UE starts 1035 a PDCP discard timer based on the PDCP discard timer configuration received 1006 from the network entity.

[0081] The UE determines 1040 whether an unsuccessful delivery confirmation (e.g., NACK) has been received. If an unsuccessful delivery confirmation has been received for the reference PDU Set, the UE discards 1070 the dependent PDU Sets or downgrades 1080 the radio bearer of the dependent PDU Sets in the corresponding PDU Set Group as described with reference to 870 / 880 in FIGs. 8-9. If an unsuccessful delivery confirmation has been received for the reference Data Burst, the UE discards 1070 the dependent Data Bursts or downgrades 1080 the radio bearer of the dependent Data Bursts in the corresponding Data Burst Group as described with reference to 870 / 880 in FIGs. 8-9. In some aspects, the UE receives a successful delivery confirmation (e.g., ACK) indicating that the network entity has successfully received and decoded the reference PDU Set / reference Data Burst (not shown). In this case, the UE transmits the dependent PDU Sets / dependent Data Bursts to the network entity. If the network entity correctly decodes the reference PDU Set / reference Data Burst and the dependent PDU Sets / dependent Data Bursts, the network entity transmits the reference PDU Set / reference Data Burst and the dependent PDU Sets / dependent Data Bursts to the core network.

[0082] If an unsuccessful delivery confirmation has not been received, the UE determines 1050 whether the PDCP discard timer has expired. If the PDCP discard timer has not expired, the UE waits for an unsuccessful delivery confirmation or expiration of the PDCP discard timer. If the UE transmitted 1030 a reference PDU Set and determines 1050 that the PDCP timer has expired, the UE discards 1070 the dependent PDU Sets or downgrades 1080 the radio bearer of the dependent PDU Sets in the corresponding PDU Set Group as described with reference to 870 / 880 in FIG. 8. If the UE transmitted 1030 a reference Data Burst and determines 1050 the PDCP timer has expired, the UE discards 1070 the dependent Data Bursts or downgrades 1080 the radio bearer of the dependent Data Bursts in the corresponding Data Burst Group as described with reference to 870 / 880 in FIGs. 8-9. Essentially, when no unsuccessful delivery confirmation was received by the UE and the PDCP discard timer expired, that means that no delivery confirmation (e.g., indicating either successful or unsuccessful delivery) was received by the UE.

[0083] FIG. 11 illustrates a flowchart of a method 1100 of a network entity performing PDU Set / Data Burst discarding / downgrading that relates to FIGs. 8-9, which illustrate signal flow diagrams showing options for PDU Set / Data Burst discarding / downgrading.

[0084] The network entity determines 1105 a network congestion level as described with reference to 805 in FIGs. 8-9.

[0085] The network entity transmits 1106 a PDCP discard timer configuration to a UE as described with reference to 806 in FIGs. 8-9.

[0086] The network entity transmits 1107 the network congestion level to a core network as described with reference to 907 in FIG 9.

[0087] The network entity receives 1108 a core network indication of PDU Set dependency within PDU Set group(s) and / or a Data Burst dependency within Data Burst group(s) as described with reference to 908 in FIG 9.

[0088] The network entity transmits 1110, to the UE, an indication of PDU Set dependency within PDU Set group(s) and / or a Data Burst dependency within Data Burst group(s) as described with reference to 810 in FIGs. 8-9.

[0089] The network entity receives 1120, from the UE, an indication of PDU Set dependency within PDU Set group(s) and / or a Data Burst dependency within Data Burst group(s) as described with reference to 820 in FIGs. 8-9.

[0090] The network entity transmits 1130, to the UE, a first PDU Set or a first Data Burst as described with reference to 930 in FIG 9.

[0091] The network entity starts 1135 a PDCP discard timer based on the PDCP discard timer configuration.

[0092] The network entity determines 1140 whether an unsuccessful delivery confirmation (e.g., NACK) has been received. If an unsuccessful delivery confirmation has been received for the reference PDU Set, the network entity discards 1170 the dependent PDU Sets or downgrades 1180 the radio bearer of the dependent PDU Sets in the corresponding PDU Set Group as described with reference to 970 / 980 in FIG. 9. If an unsuccessful delivery confirmation has been received for the reference Data Burst, the network entity discards 1170 the dependent Data Bursts or downgrades 1180 the radio bearer of the dependent Data Bursts in the corresponding Data Burst Group as described with reference to 970 / 980 in FIG. 9. In some aspects, the network entity receives (not shown) a successful delivery confirmation (e.g., ACK) indicating that the UE has successfully received and decoded the reference PDU Set / reference Data Burst. In this case, the network entity transmits the dependent PDU Sets / dependent Data Bursts to the UE. If the UE correctly decodes the dependent PDU Sets / dependent Data Bursts, the UE renders the dependent PDU Sets / dependent Data Bursts based on the reference PDU Set / reference Data Burst.

[0093] If an unsuccessful delivery confirmation has not been received, the network entity determines 1150 whether the PDCP discard timer has expired. If the PDCP discard timer has not expired, the network entity waits for an unsuccessful delivery confirmation or expiration of the PDCP discard timer. If the network entity transmitted 1130 a reference PDU Set and determines 1150 the PDCP timer has expired, the network entity discards 1170 the dependent PDU Sets or downgrades 1 180 the radio bearer of the dependent PDU Sets in the corresponding PDU Set Group as described with reference to 970 / 980 in FIG. 9. If the network entity transmitted 1130 a referenceData Burst and detennines 1150 the PDCP timer has expired, the network entity discards 1170 of the dependent Data Bursts or dow ngrades 1180 the radio bearer of the dependent Data Bursts in the corresponding Data Burst Group as described with reference to 970 / 980 in FIG. 9.

[0094] FIG. 12 illustrates a flowchart 1200 of a method of wireless communication at a first wireless communication device. With reference to FIGs. 1-10, the method may be performed by a PDU Set / Data Burst transmitting entity such as the UE 102 or network entity 104.

[0095] The first wireless communication device optionally communicates 1206 a PDCP discard timer configuration. For example, referring to FIGs. 8-9, network entity 104 transmits 806 a PDCP discard timer configuration to the UE 102.

[0096] The first wireless communication device transmits 1210, to a second wireless communication device, an indication of a dependency between a first PDU Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group. For example, referring to FIGs. 8-9, network entity 104 transmits 810, to the UE 102, a dependency between a first PDU Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group. As another example, referring to FIG. 8-9, UE 102 transmits 820, to the network entity 104, a dependency between a first PDU Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group.

[0097] The first wireless communication device transmits 1230, to the second wireless communication device, the first PDU Set or the first Data Burst. For example, referring to FIG. 8, UE 102 transmits 830 a reference PDU Set or a reference Data Burst to the network entity 104. As another example, referring to FIG. 9, network entity 104 transmits 930 a reference PDU Set or a reference Data Burst to the UE 102.

[0098] The first wireless communication device may retransmit 1260, to the second wireless communication device, the first PDU Set or the first Data Burst. For example, referring to FIG. 8, the UE 102 may retransmit 860, to the network entity 104, the reference PDU Set or the reference Data Burst based on the absence of receipt, from the network entity 104, of a successful delivery confirmation associated with the reference PDU Set or reference Data Burst. For example, referring to FIG. 9, the network entity 104 may retransmit 860, to the UE 102, the reference PDU Set or the reference Data Burst based on the absence of receipt, from the UE 102, of a successful delivery confirmation associated with the reference PDU Set or reference Data Burst.

[0099] The first wireless communication device discards 1270 the second PDU Set, based on the absence of receipt, from the second wireless communication device, of a first successful delivery confirmation associated with the first PDU Set. For example, referring to FIG. 8, the UE 102 discards 870 the dependent PDU Set, based on an absence of receipt, from the network entity104, of a first successful delivery confirmation associated with the reference PDU Set. As another example, referring to FIG. 9, the network entity 104 discards 970 the dependent PDU Set, based on the absence of receipt, from the UE 102, of a first successful delivery confirmation associated with the reference PDU Set.

[0100] The first wireless communication device discards 1270 the second Data Burst, based on the absence of receipt, from the second wireless communication device, of a second successful delivery confirmation associated with the first Data Burst. For example, referring to FIG. 8, the UE 102 discards 870 the dependent Data Burst, based on the absence of receipt, from the network entity 104, of a second successful delivery confirmation associated with the reference Data Burst. As another example, referring to FIG. 9, the network entity 104 discards 970 the dependent Data Burst, based on the absence of receipt, from the UE 102, of a second successful delivery confirmation associated with the reference Data Burst.

[0101] The first wireless communication device downgrades 1280 a radio bearer of the second PDU Set, based on the absence of receipt, from the second wireless communication device, of a first successful delivery confirmation associated with the first PDU Set. For example, referring to FIG. 8, the UE 102 downgrades 880 a radio bearer of the dependent PDU Set, based on the absence of receipt, from the network entity 104, of a first successful delivery confirmation associated with the reference PDU Set. As another example, referring to FIG. 9, the network entity 104 downgrades 980 a radio bearer of the dependent PDU Set, based on the absence of receipt, from the UE 102, of a first successful delivery confirmation associated with the reference PDU Set.

[0102] The first wireless communication device downgrades 1280 a radio bearer of the second Data Burst, based on the absence of receipt, from the second wireless communication device, of a second successful delivery confirmation associated with the first Data Burst. For example, referring to FIG. 8, the UE 102 downgrades 880 a radio bearer of the dependent Data Burst, based on the absence of receipt, from the network unit 104, of a second successful delivery confirmation associated with the reference Data Burst. As another example, referring to FIG. 9, the network entity 104 downgrades 980 a radio bearer of the dependent Data Burst, based on the absence of receipt, from the UE 102, of a second successful delivery confirmation associated with the reference Data Burst.

[0103] FIG. 12 describes a method from the point of view of the PDU Set / Data Burst transmitting entity, whereas FIG. 13 describes a method from the point of view of the PDU Set / Data Burst receiving entity.

[0104] FIG. 13 illustrates a flowchart 1300 of a method of wireless communication at a second wireless communication device. With reference to FIGs. 1-10. the method may be performed by a PDU Set / Data Burst receiving entity such as the UE 102 or network entity 104.

[0105] The second wireless communication device communicates 1306 a PDCP discard timer configuration. For example, referring to FIGs. 8-9, network entity 104 transmits 806 a PDCP discard timer configuration to the UE 102.

[0106] The second wireless communication device receives 1310, from a first wireless communication device, an indication of a dependency between a first PDU Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group. For example, referring to FIGs. 8-9, the UE 102 receives 810, from the network entity 104, a dependency between a first PDU Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group. For example, referring to FIGs. 8-9, network entity 104 receives 820, from the UE 102, a dependency between a first PDU Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group.

[0107] The second wireless communication device receives 1330, from the first wireless communication device, the first PDU Set or the first Data Burst. For example, referring to FIG. 8, network entity 104 receives 830 a reference PDU Set or a reference Data Burst from the UE 102. For example, referring to FIG. 9, UE 102 receives 930 a reference PDU Set or a reference Data Burst from the network entity 104.

[0108] The second wireless communication device transmits 1340, to the first wireless communication device, an unsuccessful delivery confirmation (e.g., NACK) based on a failure to decode the first PDU Set or the first Data Burst. For example, referring to FIG. 8, network entity 104 transmits 840 a NACK based on a failure to decode the first PDU Set or the first Data Burst. For example, referring to FIG. 9, UE 102 transmits 940 a NACK based on a failure to decode the first PDU Set or the first Data Burst.

[0109] FIG. 14 is a diagram 1400 illustrating an example of a hardware implementation for a UE apparatus 1402. The UE apparatus 1402 may be the UE 102, a component of the UE 102, or may implement UE functionality as descnbed in FIGs. 3-10 and 12. The UE apparatus 1402 may include an application processor 1406, which may have on-chip memory 1406’. In examples, the application processor 1406 may be coupled to a secure digital (SD) card 1408 and / or a display 1410. The application processor 1406 may also be coupled to a sensor(s) module 1412, a power supply 1414, an additional module of memory 1416, a camera 1418 for recording single modal video data, a video codec for encoding and decoding I-frame video and P-frame video, and / or other related components.

[0110] The UE apparatus 1402 may further include a wireless baseband processor 1426, which may be referred to as a modem. The wireless baseband processor 1426 may have on-chip memory 1426'. Along with, and similar to, the application processor 1406, the wireless baseband processor 1426 may also be coupled to the sensor(s) module 1412, the power supply 1414, the additional module of memory 1416, the camera 1418, and / or other related components. The wireless baseband processor 1426 may be additionally coupled to one or more subscriber identity module (SIM) card(s) 1420 and / or one or more transceivers 1430 (e.g., wireless RF transceivers).

[0111] Within the one or more transceivers 1430, the UE apparatus 1402 may include a Bluetooth module 1432, a wireless local area network (WLAN) module 1434, a satellite positioning system (SPS) module 1436 (e.g., global navigation satellite system (GNSS) module), and / or a cellular module 1438. The Bluetooth module 1432, the WLAN module 1434, the SPS module 1436, and the cellular module 1438 may each include an on-chip transceiver (TRX), or in some cases, just a transmitter (TX) or just a receiver (RX). The Bluetooth module 1432, the WLAN module 1434, the SPS module 1436, and the cellular module 1438 may each include dedicated antennas and / or utilize antennas 1440 for communication with one or more other nodes. For example, the UE apparatus 1402 can communicate through the transceiver(s) 1430 via the antennas 1440 with another UE (e.g., sidelink communication) and / or with a network entity 104 (e.g., uplink / downlink communication), where the network entity 104 may correspond to a base station or a unit of the base station, such as the RU 106, the DU 108, or the CU 110.

[0112] The wireless baseband processor 1426 and the application processor 1406 may each include a computer-readable medium / memory 1426', 1406', respectively. The additional module of memory 1416 may also be considered a computer-readable medium / memory. Each computer- readable medium / memory 1426', 1406', 1416 may be non-transitory. The wireless baseband processor 1426 and the application processor 1406 may each be responsible for general processing, including execution of software stored on the computer-readable medium / memory 1426', 1406', 1416. The software, when executed by the wireless baseband processor 1426 / application processor 1406, causes the wireless baseband processor 1426 / application processor 1406 to perform the various functions described herein. The computer-readable medium / memory may also be used for storing data that is manipulated by the wireless baseband processor 1426 / application processor 1406 when executing the software. The wireless baseband processor 1426 / application processor 1406 may be a component of the UE 102. The UE apparatus 1402 may be a processor chip (e.g., modem and / or application) and include just the wireless baseband processor 1426 and / or the application processor 1406. In other examples, the UE apparatus 1402 may be the entire UE 102 and include the additional modules of the apparatus 1402.

[0113] As discussed in FIG. 1 and implemented with respect to FIG. 12, the video data dependency component 140 is configured to transmit, to a network entity, an indication of a dependency between first PDU Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group. The video data dependency component 140 is further configured to transmit, to the network entity, the first PDU Set or the first Data Burst. The video data dependency component 140 is further configured to discard the second PDU Set based on an absence of a receipt from the network entity of a first successful delivery confirmation associated with the first PDU Set or the video data dependency component 140 is further configured to discard the second Data Burst based on an absence of a receipt from the network entity of a second successful delivery confirmation associated with the first Data Burst. The video data dependency component 140 may be within the application processor 1406 (e.g., at 140a), the wireless baseband processor 1426 (e.g., at 140b), or both the application processor 1406 and the wireless baseband processor 1426. The PDU Set discard component 140a- 140b may be one or more hardware components specifically configured to carry out the stated processes / algorithm, implemented by one or more processors configured to perform the stated processes / algorithm, stored within a computer-readable medium for implementation by the one or more processors, or a combination thereof.

[0114] FIG. 15 is a diagram 1500 illustrating an example of a hardware implementation for one or more network entities 104. The one or more network entities 104 may be a base station, a component of a base station, or may implement base station functionality as described in FIGs. 3- 7, 11, and 13. The one or more network entities 104 may include, or may correspond to, at least one of the RU 106, the DU, 108, or the CU 110. The CU 110 may include a CU processor 1546, which may have on-chip memory 1546'. In some aspects, the CU 110 may further include an additional module of memory 1556 and / or a communications interface 1548, both of which may be coupled to the CU processor 1546. The CU 110 can communicate with the DU 108 through a midhaul link 162, such as an Fl interface between the communications interface 1548 of the CU 110 and a communications interface 1528 of the DU 108.

[0115] The DU 108 may include a DU processor 1526, which may have on-chip memory 1526'. In some aspects, the DU 108 may further include an additional module of memory 1536 and / or the communications interface 1528, both of which may be coupled to the DU processor 1526. The DU 108 can communicate with the RU 106 through a fronthaul link 160 between the communications interface 1528 of the DU 108 and a communications interface 1508 of the RU 106.

[0116] The RU 106 may include an RU processor 1506, which may have on-chip memory 1506'. In some aspects, the RU 106 may further include an additional module of memory 1516,the communications interface 1508, and one or more transceivers 1530, all of which may be coupled to the RU processor 1506. The RU 106 may further include antennas 1540, which may be coupled to the one or more transceivers 1530, such that the RU 106 can communicate through the one or more transceivers 1530 via the antennas 1540 with the UE 102.

[0117] The on-chip memory 1506', 1526', 1546' and the additional modules of memory 1516, 1536, 1556 may each be considered a computer-readable medium / memory. Each computer-readable medium / memory may be non-transitory. Each of the processors 1506, 1526, 1546 is responsible for general processing, including execution of software stored on the computer-readable medium / memory. The software, when executed by the corresponding processor(s) 1506, 1526, 1546 causes the processor(s) 1506, 1526, 1546 to perform the various functions described herein. The computer-readable medium / memory may also be used for storing data that is manipulated by the processor(s) 1506, 1526, 1546 when executing the software. In examples, the congestion control component 150 may sit at any of the one or more network entities 104, such as at the CU 110; both the CU 110 and the DU 108; each of the CU 110, the DU 108, and the RU 106; the DU 108; both the DU 108 and the RU 106; or the RU 106.

[0118] As discussed in FIG. 1 and implemented with respect to FIG. 13, the PDU Set / Data Burst dependency component 150 is configured to transmit, to a UE, an indication of a dependency between first PDU Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group. The PDU Set / Data Burst dependency component 150 is further configured to transmit, to the UE, the first PDU Set or the first Data Burst. The PDU Set / Data Burst dependency component 150 is further configured to discard the second PDU Set, based on an absence of a receipt from the UE of a first successful delivery confirmation associated with the first PDU Set or the PDU Set / Data Burst dependency component 150 is further configured to discard the second Data Burst, based on an absence of a receipt from UE of a second successful delivery confirmation associated with the first Data Burst. The PDU Set / Data Burst dependency component 150 may be within one or more processors of the one or more network entities 104, such as the RU processor 1506 (e.g., at 150a), the DU processor 1526 (e.g., at 150b), and / or the CU processor 1546 (e.g., at 150c). The congestion control component 150a-150c may be one or more hardware components specifically configured to carry out the stated processes / algorithm, implemented by one or more processors 1506, 1526, 1546 configured to perform the stated processes / algorithm, stored within a computer-readable medium for implementation by the one or more processors 1506, 1526, 1546, or a combination thereof.

[0119] The specific order or hierarchy of blocks in the processes and flowcharts disclosed herein is an illustration of example approaches. Hence, the specific order or hierarchy of blocksin the processes and flowcharts may be rearranged. Some blocks may also be combined or deleted. Dashed lines may indicate optional elements of the diagrams. The accompanying method claims present elements of the various blocks in an example order, and are not limited to the specific order or hierarchy presented in the claims, processes, and flowcharts.

[0120] The detailed description set forth herein describes various configurations in connection with the drawings and does not represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough explanation of various concepts. However, these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

[0121] Aspects of wireless communication systems, such as telecommunication systems, are presented with reference to various apparatuses and methods. These apparatuses and methods are described in the following detailed description and are illustrated in the accompanying drawings by various blocks, components, circuits, processes, call flows, systems, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, computer software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0122] An element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems-on-chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PUDs), state machines, gated logic, discrete hardware circuits, and other similar hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software, which may be referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, or any combination thereof.

[0123] If the functionality described herein is implemented in software, the functions may be stored on, or encoded as, one or more instructions or code on a computer-readable medium, such as a non-transitory computer-readable storage medium. Computer-readable media includescomputer storage media and can include a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer. Storage media may be any available media that can be accessed by a computer.

[0124] Aspects, implementations, and / or use cases described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, the aspects, implementations, and / or use cases may come about via integrated chip implementations and other non-module-component based devices, such as enduser devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchasing devices, medical devices, artificial intelligence (Al)-enabled devices, machine learning (ML)-enabled devices, etc. The aspects, implementations, and / or use cases may range from chip-level or modular components to non-modular or non-chip-level implementations, and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more techniques described herein.

[0125] Devices incorporating the aspects and features described herein may also include additional components and features for the implementation and practice of the claimed and described aspects and features. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes, such as hardware components, antennas, RF-chains, power amplifiers, modulators, buffers, processor(s), interleavers, adders / summers, etc. Techniques described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated or disaggregated components, end-user devices, etc., of varying configurations.

[0126] The description herein is provided to enable a person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not limited to the aspects described herein, but are to be interpreted in view of the full scope of the present disclosure consistent with the language of the claims.

[0127] Reference to an element in the singular does not mean “one and only one” unless specifically stated, but rather “one or more.” Terms such as “if,” “when,” and “while” do not imply an immediate temporal relationship or reaction. That is, these phrases, e.g., “when,” do not imply an immediate action in response to or during the occurrence of an action, but simply imply that if a condition is met then an action will occur, but without requiring a specific or immediate time constraint for the action to occur. The terms “may”, “might”, and “can”, as used in this disclosure,often carry certain connotations. For example, “may” refers to a pemiissible feature that may or may not occur, “might” refers to a feature that probably occurs, and “can” refers to a capability (e.g., capable of). The phrase “For example” often carries a similar connotation to “may” and, therefore, “may” is sometimes excluded from sentences that include “for example” or other similar phrases.

[0128] Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C” or “one or more of A, B, or C” include any combination of A, B, and / or C, such as A and B, A and C, B and C, or A and B and C, and may include multiples of A, multiples of B, and / or multiples of C, or may include A only, B only, or C only. Sets should be interpreted as a set of elements where the elements number one or more. Moreover, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from the context, the phrase “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B. Terms or articles such as “a”, “an”, and / or “the” may refer to one of an item, feature, element, etc., that the term or article precedes, or may refer to more than one of said item, feature, element, etc. that the term or article precedes. For example, the recitation “a widget” does not preclude reference to multiples of said widget, as “multiple widgets” necessarily includes “a widget”. Hence, the recitation “a widget” may be interpreted as “at least one widget” or, similarly, interpreted as “one or more widgets”.

[0129] Unless otherwise specifically indicated, ordinal terms such as “first” and “second” do not necessarily imply an order in time, sequence, numerical value, etc., but are used to distinguish between different instances of a term or phrase that follows each ordinal term. Reference numbers, as used in the specification and figures, are sometimes cross-referenced among drawings to denote same or similar features. A feature that is exactly the same in multiple drawings may be labeled with the same reference number in the multiple drawings. A feature that is similar among the multiple drawings, but not exactly the same, may be labeled with reference numbers that have different leading numbers, but have one or more of the same trailing numbers (e.g., 206, 306, 406, etc., may refer to similar features in the drawings). Sometimes an “X” is used to universally denote multiple variations of a feature. For instance, “X06” can universally refer to all reference numbers that end in “06” (e.g., 206, 306, 406, etc.).

[0130] Structural and functional equivalents to elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are encompassed by the claims. The words “module,” “mechanism,” “element,” “device,” and the like may not be a substitute for theword “means.” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for.” As used herein, the phrase “based on” shall not be construed as a reference to a closed set of information, one or more conditions, one or more factors, or the like. In other words, the phrase “based on A”, where “A” may be information, a condition, a factor, or the like, shall be construed as “based at least on A” unless specifically recited differently.

[0131] The following examples are illustrative only and may be combined with other examples or teachings described herein, without limitation.

[0132] Example 1 is a method of wireless communication at a first wireless communication device, comprising transmitting, to a second wireless communication device, an indication of dependency between first protocol data unit, PDU, Set and a second PDU Set within a PDU Set group or a dependency between a first Data Burst and a second Data Burst within a Data Burst group; transmitting, to the second wireless communication device, the first PDU Set or the first Data Burst.

[0133] Example 2 may be combined with Example 1 and includes the PDU Set group includes a reference PDU Set and a dependent PDU Set, the dependent PDU Set including an indicator of a sequence number of the reference PDU Set.

[0134] Example 3 may be combined with Example 2 and further includes the reference PDU Set is associated with a first video frame and the dependent PDU Set is associated with a second video frame.

[0135] Example 4 may be combined with any of Examples 1-3 and further includes the first PDU Set includes a reference PDU Set and the method further includes discarding all PDU Sets with the PDU Set group.

[0136] Example 5 may be combined with any of Examples 1-4 and further includes the Data Burst group includes a reference Data Burst and a dependent Data Burst, the dependent Data Burst including an indicator of a sequence number of the reference Data Burst.

[0137] Example 6 may be combined with any of Examples 1-4 and further includes the reference Data Burst is associated with a first video frame and the dependent Data Burst is associated with a second video frame.

[0138] Example 7 may be combined with any of Examples 1-6 and further includes the first PDU Set includes a video i-slice and the second PDU Set includes a video p-slice.

[0139] Example 8 may be combined with any of Examples 1-7 and further includes the first PDU Set includes a first video p-slice and the second PDU Set includes a second video p-slice.

[0140] Example 9 may be combined with any of Examples 1 -8 and further includes the first Data Burst includes at least one PDU Set.

[0141] Example 10 may be combined with any of Examples 1-9 and further includes downgrading, based on the absence of the first acknowledgment associated with the first PDU Set, a radio bearer associated with a third PDU Set or downgrading, based on the absence of the second acknowledgment associated with the first Data Burst, a radio bearer associated with a third Data Burst.

[0142] Example 11 may be combined with any of Examples 1-10 and further includes transmitting the indication via time sensitive communication assistance information, TSCA1, uplink control information, downlink control information, DCI, or a medium access controlcontrol element, MAC-CE.

[0143] Example 12 may be combined with any of Examples 1-11 and further includes starting a PDCP discard timer when the first PDU Set or the first Data Burst arrives in a transmit buffer. The discarding the second PDU Set is further based on the PDCP discard timer expiring or the discarding the second Data Burst is further based on the PDCP discard timer expiring.

[0144] Example 13 may be combined with any of Examples 1-12 and further includes receiving, from an application layer or a core network, the dependency between the PDU Sets within the PDU Set group or the dependency between the Data Bursts within the Data Burst group.

[0145] Example 14 may be combined with any of Examples 1-13 and further includes the discarding the second PDU Set is further based on a PDU Set importance, PSI, of the second PDU Set or the discarding the second Data Burst is further based on a PSI of the second Data Burst.

[0146] Example 15 may be combined with any of Examples 1-14 and further includes transmitting, to the second wireless communication device, a third PDU Set, the third PDU Set including a reference PDU Set or transmitting, to the second wireless communication device, a third Data Burst, the third Data Burst including a reference Data Burst.

[0147] Example 16 may be combined with any of Examples 1-15 and further includes the indication includes at least one of: a starting PDU Set sequence number, SN, within the PDU Set group; an ending PDU Set SN within the PDU Set group; a starting Data Burst SN within the Data Burst group; an ending Data Burst SN within the Data Burst group; a reference PDU Set in the PDU Set group; a dependent PDU Set in the PDU Set group; a reference Data Burst in the Data Burst group; a dependent Data Burst in the Data Burst group; a starting PDU SN within the Data Burst group; an ending PDU SN within the Data Burst group; a number of PDUs within the PDU Set group; a number of PDU Sets within the PDU Set group; a number of PDUs within the Data Burst group; a number of PDU Sets within the Data Burst group; or a number of Data Bursts within the Data Burst group.

[0148] Example 17 may be combined with any of Examples 1 -16 and further includes receiving the dependency between the PDU Sets or the Data Bursts via a general packet radioservice tunneling protocol user plane, GTP-U, header, a real-time transport protocol, RTP, header, or control plane signaling.

[0149] Example 18 may be combined with any of Examples 1-17 and further includes transmitting the indication based on a network congestion level satisfying a threshold.

[0150] Example 19 may be combined with any of Examples 1-18 and further includes the wireless communication device includes a UE or a network entity.

[0151] Example 20 may be combined with any of Examples 1-19 and further includes discarding the second PDU Set, based on an absence of a receipt from the second wireless communication device of a first successful delivery confirmation associated with the first PDU Set; or the second Data Burst, based on an absence of a receipt from the second wireless communication device of a second successful delivery confirmation associated with the first Data Burst.

[0152] Example 21 is a method of wireless communication at a second wireless communication device, comprising receiving, from a first wireless communication device, an indication of: a dependency between protocol data unit, PDU, Sets within a PDU Set group; or a dependency between Data Bursts within a Data Burst group; receiving, from the first wireless communication device, a first PDU Set or a first Data Burst; transmitting, to the first wireless communication device, a NACK based on a failure to decode the first PDU Set or the first Data Burst.

[0153] Example 22 is an apparatus for wireless communication for implementing a method as in any of Examples 1-21.

[0154] Example 23 is an apparatus for wireless communication including means for implementing a method as in any of Examples 1-21.

[0155] Example 24 is a non-transitory computer-readable medium storing computer executable code, the code when executed by a processor causes the processor to implement a method as in any of Examples 1-21.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A method of wireless communication performed by a first wireless communication device, the method comprising: transmitting (810, 820), to a second wireless communication device, an indication of: a dependency between a first protocol data unit, PDU, Set and a second PDU Set within a PDU Set group; or a dependency between a first Data Burst and a second Data Burst within a Data Burst group; and transmitting (830, 930), to the second wireless communication device, the first PDU Set or the first Data Burst.

2. The method of claim 1, wherein the PDU Set group comprises a reference PDU Set and a dependent PDU Set, the dependent PDU Set comprising an indicator of a sequence number of the reference PDU Set.

3. The method of any of claims 1 to 2, wherein the first PDU Set comprises a reference PDU Set and the method further comprises: discarding all PDU Sets with the PDU Set group based on an absence of receipt of a first successful delivery confirmation associated with the first PDU Set.

4. The method of claim 1 , wherein the Data Burst group comprises a reference Data Burst and a dependent Data Burst, the dependent Data Burst comprising an indicator of a sequence number of the reference Data Burst.

5. The method of any of claims 1 to 4, further comprising: discarding (870, 970) the second PDU Set, based on an absence of receipt from the second wireless communication device of a first successful delivery confirmation associated with the first PDU Set; or discarding (870, 970) the second Data Burst, based on an absence of receipt from the second wireless communication device of a second successful delivery confirmation associated with the first Data Burst.

6. The method of any of claims 1 to 5, further comprising:downgrading (880, 980) a radio bearer associated with the second PDU Set, based on an absence of receipt from the second wireless communication device of a first successful delivery confirmation associated with the first PDU Set; or downgrading (880, 980), a radio bearer associated with the second Data Burst, based on an absence of receipt from the second wireless communication device of a second successful delivery confirmation associated with the first Data Burst.

7. The method of any of claims 1 to 6, wherein the transmitting (810) the indication comprises transmitting (810) the indication via time sensitive communication assistance information, TSCAI, uplink control information, downlink control information, DCI, or a medium access control-control element, MAC-CE.

8. The method of any of claims 1 to 7, further comprising: starting a packet data convergence protocol, PDCP, discard timer (850) when the first PDU Set or the first Data Burst arrives in a transmit buffer; discarding (870, 970) the second PDU Set based on the PDCP discard timer expiring; or discarding (870, 970) the second Data Burst based on the PDCP discard timer expiring.

9. The method of any of claims 1 to 8, further comprising: receiving, from an application layer or a core network (120): the dependency between the PDU Sets within the PDU Set group; or the dependency between the Data Bursts within the Data Burst group.

10. The method of any of claims 1 to 9, further comprising: discarding (870, 970) the second PDU Set based on a PDU Set importance, PSI, of the second PDU Set; or discarding (870, 970) the second Data Burst based on a PSI of the second Data Burst.

11. The method of any of claims 1 to 10, further comprising: transmitting (860), to the second wireless communication device, a third PDU Set, wherein the third PDU Set comprises a reference PDU Set; or transmitting (860), to the second wireless communication device, a third Data Burst, wherein the third Data Burst comprises a reference Data Burst.

12. The method of any of claims 1 to 11, wherein the indication comprises one of:a starting PDU Set sequence number, SN, within the PDU Set group; an ending PDU Set SN within the PDU Set group; a starting Data Burst SN wi thin the Data Burst group; an ending Data Burst SN within the Data Burst group; a reference PDU Set in the PDU Set group; a dependent PDU Set in the PDU Set group; a reference Data Burst in the Data Burst group; a dependent Data Burst in the Data Burst group; a starting PDU SN within the Data Burst group; an ending PDU SN within the Data Burst group; a number of PDUs within the PDU Set group; a number of PDU Sets within the PDU Set group; a number of PDUs within the Data Burst group; a number of PDU Sets within the Data Burst group; or a number of Data Bursts within the Data Burst group.

13. The method of any of claims 1 to 12, wherein the wireless communication device comprises: a user equipment, UE,; or a network entity.

14. A method of wireless communication performed by a second wireless communication device, the method comprising: receiving (810, 820), from a first wireless communication device, an indication of: a dependency between a first protocol data unit, PDU, Set and a second PDU Set within a PDU Set group; or a dependency between a first Data Burst and a second Data Burst within a Data Burst group; receiving (830, 930), from the first wireless communication device, the first PDU Set or the first Data Burst; and transmitting (840), to the first wireless communication device, a negative acknowledgement, NACK, based on a failure to decode the first PDU Set or the first Data Burst.

15. An apparatus for wireless communication comprising a transceiver, a memory, and a processor coupled to the transceiver and the memory and configured to implement a method as in any of claims 1-14.

Images