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WO2024160341A1 - Récupération rapide à partir d'un transfert avec un mode de distribution irrégulière - Google Patents

Récupération rapide à partir d'un transfert avec un mode de distribution irrégulière Download PDF

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Publication number
WO2024160341A1
WO2024160341A1 PCT/EP2023/052155 EP2023052155W WO2024160341A1 WO 2024160341 A1 WO2024160341 A1 WO 2024160341A1 EP 2023052155 W EP2023052155 W EP 2023052155W WO 2024160341 A1 WO2024160341 A1 WO 2024160341A1
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WIPO (PCT)
Prior art keywords
receiving
protocol entity
data packets
transport protocol
data
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2023/052155
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English (en)
Inventor
Torsten DUDDA
Henning Wiemann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Priority to CN202380092027.5A priority Critical patent/CN120604481A/zh
Priority to PCT/EP2023/052155 priority patent/WO2024160341A1/fr
Priority to EP23702574.7A priority patent/EP4659392A1/fr
Publication of WO2024160341A1 publication Critical patent/WO2024160341A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/02—Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
    • H04W36/023—Buffering or recovering information during reselection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1829—Arrangements specially adapted for the receiver end
    • H04L1/1858—Transmission or retransmission of more than one copy of acknowledgement message
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/34—Flow control; Congestion control ensuring sequence integrity, e.g. using sequence numbers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/04—Error control

Definitions

  • the present invention relates to the field of fast recovery from handover procedures .
  • the present invention relates to a receiving data link layer protocol entity and a method thereof which performs delivery of data packets to a receiving higher layer transport protocol entity for fast recovery from handover .
  • the present invention relates to packet data convergence protocol (PDCP ) delivery for fast handover recovery .
  • PDCP packet data convergence protocol
  • a radio connection of a wireless device to a network is moved from a source cell to a target cell .
  • the source cell may be served by a source network node , like a source gNB, and the target cell may be served by a target network node , like a target gNB .
  • the wireless device may be a terminal , a user equipment (UE ) , or the like .
  • protocol operations during a handover are described for the above mentioned 3GPP 5G deployment .
  • the wireless device protocol instances and the network protocol instances of respective protocol layers may undergo the following procedures :
  • Radio Access Network (RAN) protocol layers hence the physical layer ( PHY) , medium acces s control (MAC ) layer, and radio link control (RLC ) layer, of the wireless device may be reset .
  • the packet data convergence protocol (PDCP) layer is a RAN protocol layer or a sublayer of the protocol stack. It may be a sublayer of the layer 2/MAC according to the Open Systems Interconnection (OSI) model.
  • the PDCP layer, of the wireless device which serves as the handover/mobility anchor protocol may undergo a reestablishment procedure, which includes the following:
  • the PDCP sequence numbers and reordering timer may be reset. Data in flight, that has not yet been received, may be lost. Unsent data may be transmitted after the connection is established in the target cell. Buffer forwarding may be used in downlink (DL) to transport unsent data from the source network node, like the source gNB, to the target network node, like the target gNB.
  • DL downlink
  • a receiving PDCP entity for the RAN layers mentioned above, of a receiving node e.g. the wireless device for DL, may perform out-of-order delivery of any data that may have already been received before the handover, to a receiving higher layer transport protocol entity of the receiving node, without waiting for missing packets from the PDCP sequence number order.
  • the PDCP sequence numbers and reordering timers may continue, i.e. may be maintained. Data in flight, that has not been received, may be retransmitted as well as unsent data after the connection is established in the target cell. Buffer forwarding may be used for both sent but unacknowledged data and unsent data from a source network node to a target network node.
  • the receiving PDCP entity might not perform out-of-order delivery to the receiving higher layer transport protocol entity, i.e. the receiving PDCP entity may wait until missing packets are retransmitted. In other words , the receiving PDCP entity may wait until gaps in the sequence numbering are closed or at least until a reordering timer expires .
  • a PDCP reordering timer may be used to define a maximum waiting time for outstanding packets from PDCP sequence numbering . This way packets that were received from lower layers out of sequence , e . g . since transmitted with di f ferent HARQ processes with di f ferent transmission/retransmission delays , are re-ordered at PDCP and provided to higher layers in-order .
  • PDCP out-of-order delivery can be optionally configured for continuous operation (not speci fically for handover ) in order to enable lower latency, more interactivity, and less head- of-line blocking for services .
  • Modern transport protocols are expected to cope well with out-of-order delivery .
  • Transport protocols such as Transmission Control Protocol ( TCP ) , Quick UDP Internet Connections (QUIC ) , or the like , and their congestion control algorithms have to identi fy congestion on the transport connection to be able to adj ust the number of packets brought into flight and to avoid further congestion . This is done by observing packet reordering, i . e . number and time of packets received after a missing packet .
  • the transmitting transport protocol entity of a transmitting node executing the transport protocol gets this information based on acknowledgements (ACKs ) received from the receiving transport protocol entity of a receiving node .
  • ACKs acknowledgements
  • the transmitting node may be a network node and, thus , the transmitting transport protocol entity may perform functions of the network node .
  • the receiving node may be a wireless device and, thus , the receiving transport protocol entity may perform functions of the wireless device .
  • the transmitting node may be the wireless device and, thus , the transmitting transport protocol entity may perform functions of the wireless device .
  • the receiving node may be a network node and, thus , the receiving transport protocol entity may perform functions of the network node .
  • One challenge is to distinguish congestion events from noncongestion events related to reordering on the connection .
  • the challenge on radio protocol design is to balance achievable throughput and latency . Higher throughput may be possible i f available bandwidth is fully utili zed which requires that transport protocol congestion control algorithms bring suf ficient data in flight . This requires that re-ordering introduced in NR is not falsely interpreted as congestion by the transport .
  • RAN protocols might not handle handover related retransmissions themselves but leave retransmissions of lost data packets during the handover procedure to the transport protocols , such as TCP or QUIC . Due to the acknowledgment clocked and timer-based nature of these protocols , delays with retransmission of these packets are expected .
  • these obj ects may be met by adj usting protocol behaviour at the data packet receiving side .
  • the herein presented techniques and methods may combine wanted ef fects like lower latencies achieved with, for example , PDCP data packet delivery, without or less negative impact on throughput/ latency when handover procedures occur .
  • a method, performed by a receiving data link layer protocol entity comprises the step o f delivering a plurality of data packets to a receiving higher layer transport protocol entity . Furthermore, the method comprises the steps of re-delivering a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number of times during a handover procedure .
  • a receiving node comprises a processor into which a receiving data link layer protocol entity is loadable . Execution of the receiving data link layer protocol entity by the processor causes the receiving node to delivering a plurality of data packets to a receiving higher layer transport protocol entity . Furthermore, the receiving node is caused to re-deliver a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number of times during a handover procedure .
  • a receiving node comprises a receiving data link layer protocol entity .
  • the receiving node is configured to deliver a plurality of data packets to a receiving higher layer transport protocol entity and redeliver a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number of times during a handover procedure .
  • a computer program comprises program code to be executed by processor to operate a receiving data link layer protocol entity .
  • Execution of the program code causes the receiving data link layer protocol entity to perform operations which comprise delivering a plurality of data packets to a receiving higher layer transport protocol entity .
  • the operations comprise performing re-delivering a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number of times during a handover procedure .
  • a computer program product comprises a non-transitory storage medium which includes program code to be executed by processing circuitry to operate a receiving data link layer protocol entity .
  • Execution of the program code causes the receiving data link layer protocol entity to perform operations which comprise delivering a plurality of data packets to a receiving higher layer transport protocol entity .
  • the operations comprise re-delivering a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number of times during a handover procedure .
  • a method implemented by a host operating in a communication system that further includes a network node and a user equipment (UE ) comprises providing user data for the UE . Furthermore, the method comprises initiating a transmission carrying the user data to the UE via a cellular network comprising the network node .
  • the UE performs the following operations to receive the user data from the host .
  • the operations comprise to deliver of a plurality of data packets to a receiving higher layer transport protocol entity and re-deliver a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number of times during a handover procedure .
  • the UE comprises a communication interface and processing circuitry .
  • the communication interface and processing circuity of the UE are configured to perform the following operations to receive the user data from the host .
  • the operations comprise to deliver a plurality of data packets to a receiving higher layer transport protocol entity and re-deliver a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number of times during a handover procedure .
  • the user data originates from a transmission which the network node has received from the UE .
  • the network node performs the following operations to receive the user data from the UE for the host .
  • the operations comprise to del iver a plurality of data packets to a receiving higher layer transport protocol entity and re-deliver a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number o f times during a handover procedure .
  • the network node has a communication interface and processing circuitry .
  • the processing circuitry of the network node is configured to perform the following operations to receive the user data from the UE for the host .
  • the operations comprise to deliver of a plurality of data packets to a receiving higher layer transport protocol entity and re-deliver a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number o f times during a handover procedure .
  • FIG . 1 shows an example of a communication system in accordance with some embodiments .
  • FIG . 2 is a block diagram of a host , which may be an embodiment of the host of FIG . 1 , in accordance with various aspects described herein .
  • FIG . 3 shows a communication diagram of a host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments .
  • FIG . 4A illustrates data transmission between a network node and a wireless device for downlink ( DL ) according to an embodiment .
  • FIG . 4B illustrates data transmission between a network node and a wireless device for uplink (UL ) according to an embodiment .
  • FIG . 5 illustrates a receiving data link layer protocol entity and a receiving higher layer transport protocol entity of a receiving node according to an embodiment .
  • FIG . 6 illustrates a transmitting data link layer protocol entity and a transmitting higher layer transport protocol entity of a transmitting node according to an embodiment .
  • FIG . 7 illustrates a system overview with higher layer transport protocol entities and data link layer protocol entities of a transmitting node and a receiving node according to an embodiment .
  • Fig . 8 illustrates an exemplary system overview with transport protocol entities as higher layer transport protocol entities and PDCP entities as data link layer protocol entities of a transmitting node and a receiving node .
  • FIG . 9 illustrates an exemplary method performed by a receiving data link layer protocol entity for triggering further data packet transmissions .
  • FIG . 10 illustrates an example for triggering further data transmission .
  • FIG . 11 illustrates an exemplary method performed by a system comprising a transmitting node and a receiving node for triggering fast handover recovery .
  • FIG . 12 illustrates an exemplary configuration for a receiving node .
  • FIG . 13 illustrates an exemplary configuration for a transmitting node .
  • FIG . 14 shows an example of respective hardware which may use software to implement the functions described herein .
  • FIG . 15 illustrates simulation results using the herein described method for fast handover recovery according to an embodiment .
  • FIG . 16 illustrates further simulation results using the herein described method for fast handover recovery according to an embodiment .
  • FIG . 1 shows an example of a communication system 100 in accordance with some embodiments .
  • the communication system 100 includes a telecommunication network 102 that includes an access network 104 , such as a radio access network (RAN) , and a core network 106 , which includes one or more core network nodes 108 .
  • the access network 104 includes one or more access network nodes , such as network nodes 110a and 110b ( one or more of which may be generally referred to as network nodes 110 ) , or any other similar 3rd Generation Partnership Proj ect ( 3GPP ) access node or non-3GPP access point .
  • 3GPP 3rd Generation Partnership Proj ect
  • the network nodes 110 facilitate direct or indirect connection of user equipment (UE ) , such as by connecting UEs 112a, 112b, 112c, and 112d ( one or more of which may be generally referred to as UEs 112 ) to the core network 106 over one or more wireless connections .
  • UE user equipment
  • Example wireless communications over a wireless connection include transmitting and/or receiving wireless signals using electromagnetic waves , radio waves , infrared waves , and/or other types of signals suitable for conveying information without the use of wires , cables , or other material conductors .
  • the communication system 100 may include any number of wired or wireless networks , network nodes , UEs , and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections .
  • the communication system 100 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system .
  • the UEs 112 may be any of a wide variety of communication devices , including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes 110 and other communication devices .
  • the network nodes 110 are arranged, capable , configured, and/or operable to communicate directly or indirectly with the UEs 112 and/or with other network nodes or equipment in the telecommunication network 102 to enable and/or provide network access , such as wireless network access , and/or to perform other functions , such as administration in the telecommunication network 102 .
  • the core network 106 connects the network nodes 110 to one or more hosts , such as host 116 . These connections may be direct or indirect via one or more intermediary networks or devices . In other examples , network nodes may be directly coupled to hosts .
  • the core network 106 includes one more core network nodes ( e . g . , core network node 108 ) that are structured with hardware and software components . Features of these components may be substantially similar to those described with respect to the UEs , network nodes , and/or hosts , such that the descriptions thereof are generally applicable to the corresponding components of the core network node 108 .
  • Example core network nodes include functions of one or more of a Mobile Switching Center (MSC ) , Mobility Management Entity (MME ) , Home Subscriber Server (HSS ) , Access and Mobility Management Function (AMF) , Session Management Function ( SMF) , Authentication Server Function (AUSF) , Subscription Identi bomb De-concealing function ( S IDF) , Uni fied Data Management (UDM) , Security Edge Protection Proxy ( SEPP ) , Network Exposure Function (NEF) , and/or a User Plane Function (UPF) .
  • MSC Mobile Switching Center
  • MME Mobility Management Entity
  • HSS Home Subscriber Server
  • AMF Access and Mobility Management Function
  • SMF Session Management Function
  • AUSF Authentication Server Function
  • S IDF Subscription Identi fier De-concealing function
  • UDM Uni fied Data Management
  • SEPP Security Edge Protection Proxy
  • NEF Network Exposure Function
  • UPF User Plane Function
  • the host 116 may be under the ownership or control of a service provider other than an operator or provider of the access network 104 and/or the telecommunication network 102 , and may be operated by the service provider or on behal f o f the service provider .
  • the host 116 may host a variety of applications to provide one or more service . Examples of such applications include live and pre-recorded audio/video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.
  • the communication system 100 of Figure 1 enables connectivity between the UEs, network nodes, and hosts.
  • the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM) ; Universal Mobile Telecommunications System (UMTS) ; Long Term Evolution (LTE) , and/or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G) ; wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi) ; and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax) , Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and/or any low-power wide- area network (LPWAN) standards such as LoRa and Sigfox.
  • GSM Global System for Mobile Communications
  • UMTS Universal Mobile Telecommunication
  • the telecommunication network 102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 102. For example, the telecommunications network 102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and/or Massive Machine Type Communication (mMTC) /Massive loT services to yet further UEs. In some examples, the UEs 112 are configured to transmit and/or receive information without direct human interaction.
  • URLLC Ultra Reliable Low Latency Communication
  • eMBB Enhanced Mobile Broadband
  • mMTC Massive Machine Type Communication
  • the UEs 112 are configured to transmit and/or receive information without direct human interaction.
  • a UE may be designed to transmit information to the access network 104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 104.
  • a UE may be configured for operating in single- or multi-RAT or multistandard mode.
  • a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC) , such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC) .
  • MR-DC multi-radio dual connectivity
  • E-UTRAN Evolved-UMTS Terrestrial Radio Access Network
  • EN-DC New Radio - Dual Connectivity
  • the hub 114 communicates with the access network 104 to facilitate indirect communication between one or more UEs (e.g., UE 112c and/or 112d) and network nodes (e.g., network node 110b) .
  • the hub 114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs.
  • the hub 114 may be a broadband router enabling access to the core network 106 for the UEs.
  • the hub 114 may be a controller that sends commands or instructions to one or more actuators in the UEs.
  • the hub 114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data.
  • the hub 114 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 114 then provides to the UE either directly, after performing local processing, and/or after adding additional local content.
  • the hub 114 acts as a proxy server or orchestrator for the UEs , in particular in i f one or more of the UEs are low energy loT devices .
  • the hub 114 may have a constant /persistent or intermittent connection to the network node 110b .
  • the hub 114 may also allow for a di f ferent communication scheme and/or schedule between the hub 114 and UEs ( e . g . , UE 112c and/or 112d) , and between the hub 114 and the core network 106 .
  • the hub QQ114 is connected to the core network 106 and/or one or more UEs via a wired connection .
  • the hub 114 may be configured to connect to an M2M service provider over the access network 104 and/or to another UE over a direct connection .
  • UEs may establish a wireless connection with the network nodes 110 while still connected via the hub 114 via a wired or wireless connection .
  • the hub 114 may be a dedicated hub - that is , a hub whose primary function is to route communications to/ from the UEs from/to the network node 110b .
  • the hub 114 may be a nondedicated hub - that is , a device which is capable of operating to route communications between the UEs and network node 110b, but which is additionally capable of operating as a communication start and/or end point for certain data channels .
  • FIG . 2 is a block diagram of a host 200 , which may be an embodiment of the host 116 of FIG . 1 , in accordance with various aspects described herein .
  • the host 200 may be or comprise various combinations hardware and/or software , including a standalone server, a blade server, a cloud- implemented server, a distributed server, a virtual machine , container, or processing resources in a server farm .
  • the host 200 may provide one or more services to one or more UEs .
  • the host 200 includes processing circuitry 202 that i s operatively coupled via a bus 204 to an input/output interface 206, a network interface 208, a power source 210, and a memory 212.
  • processing circuitry 202 that i s operatively coupled via a bus 204 to an input/output interface 206, a network interface 208, a power source 210, and a memory 212.
  • Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such that the descriptions thereof are generally applicable to the corresponding components of host 200.
  • the memory 212 may include one or more computer programs including one or more host application programs 214 and data 216, which may include user data, e.g., data generated by a UE for the host 200 or data generated by the host 200 for a UE .
  • Embodiments of the host 200 may utilize only a subset or all of the components shown.
  • the host application programs 214 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (WC) , High Efficiency Video Coding (HEVC) , Advanced Video Coding (AVC) , MPEG, VP9) and audio codecs (e.g., FLAG, Advanced Audio Coding (AAC) , MPEG, G.711) , including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems) .
  • video codecs e.g., Versatile Video Coding (WC) , High Efficiency Video Coding (HEVC) , Advanced Video Coding (AVC) , MPEG, VP9
  • audio codecs e.g., FLAG, Advanced Audio Coding (AAC) , MPEG, G.711
  • UEs e.g., handsets, desktop computers, wearable display systems, heads-up display systems
  • the host application programs 214 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 200 may select and/or indicate a different host for over-the-top services for a UE .
  • the host application programs 214 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP) , Real-Time Streaming Protocol (RTSP) , Dynamic Adaptive Streaming over HTTP (MPEG-DASH) , etc .
  • FIG. 3 shows a communication diagram of a host 302 communicating via a network node 304 with a UE 306 over a partially wireless connection in accordance with some embodiments.
  • Example implementations, in accordance with various embodiments, of the UE (such as a UE 112a of FIG. 1) , network node (such as network node 110a of FIG. 1) , and host (such as host 116 of FIG. 1 and/or host 200 of FIG. 2) discussed in the preceding paragraphs will now be described with reference to FIG. 3.
  • host 302 Like host 200, embodiments of host 302 include hardware, such as a communication interface, processing circuitry, and memory.
  • the host 302 also includes software, which is stored in or accessible by the host 302 and executable by the processing circuitry.
  • the software includes a host application that may be operable to provide a service to a remote user, such as the UE 306 connecting via an over-the- top (OTT) connection 350 extending between the UE 306 and host 302.
  • OTT over-the- top
  • a host application may provide user data which is transmitted using the OTT connection 350.
  • the network node 304 includes hardware enabling it to communicate with the host 302 and UE 306.
  • the connection 360 may be direct or pass through a core network (like core network 106 of FIG. 1) and/or one or more other intermediate networks, such as one or more public, private, or hosted networks.
  • a core network like core network 106 of FIG. 1
  • an intermediate network may be a backbone network or the Internet.
  • the UE 306 includes hardware and software, which is stored in or accessible by UE 306 and executable by the UE's processing circuitry.
  • the software includes a client application, such as a web browser or operator-specific "app" that may be operable to provide a service to a human or non-human user via UE 306 with the support of the host 302.
  • a client application such as a web browser or operator-specific "app" that may be operable to provide a service to a human or non-human user via UE 306 with the support of the host 302.
  • an executing host application may communicate with the executing client application via the OTT connection 350 terminating at the UE 306 and host 302.
  • the UE ' s client application may receive request data from the host ' s host application and provide user data in response to the request data .
  • the OTT connection 350 may trans fer both the request data and the user data .
  • the UE ' s client application may interact with the user to generate the user data that it provides
  • the OTT connection 350 may extend via a connection 360 between the host 302 and the network node 304 and via a wireless connection 370 between the network node 304 and the UE 306 to provide the connection between the host 302 and the UE 306 .
  • the connection 360 and wireless connection 370 over which the OTT connection 350 may be provided, have been drawn abstractly to illustrate the communication between the host 302 and the UE 306 via the network node 304 , without explicit reference to any intermediary devices and the precise routing of messages via these devices .
  • the host 302 provides user data, which may be performed by executing a host application .
  • the user data is as sociated with a particular human user interacting with the UE 306 .
  • the user data is associated with a UE 306 that shares data with the host 302 without explicit human interaction .
  • the host 302 initiates a transmission carrying the user data towards the UE 306 .
  • the host 302 may initiate the transmission responsive to a request transmitted by the UE 306 .
  • the request may be caused by human interaction with the UE 306 or by operation of the client application executing on the UE 306 .
  • the transmission may pass via the network node 304 , in accordance with the teachings of the embodiments described throughout this disclosure . Accordingly, in step 312 , the network node 304 transmits to the UE 306 the user data that was carried in the transmission that the host 302 initiated, in accordance with the teachings of the embodiments described throughout this disclosure . In step 314 , the UE 306 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 306 associated with the host application executed by the host 302 .
  • the UE 306 executes a client application which provides user data to the host 302 .
  • the user data may be provided in reaction or response to the data received from the host 302 .
  • the UE 306 may provide user data, which may be performed by executing the client application .
  • the client application may further consider user input received from the user via an input/output interface of the UE 306 .
  • the UE 306 initiates , in step 318 , transmission of the user data towards the host 302 via the network node 304 .
  • the network node 304 receives user data from the UE 306 and initiates transmission of the received user data towards the host 302 .
  • the host 302 receives the user data carried in the transmission initiated by the UE 306 .
  • One or more of the various embodiments improve the performance of OTT services provided to the UE 306 using the OTT connection 350 , in which the wireless connection 370 forms the last segment . More precisely, the teachings of these embodiments may improve the latency and throughput also for handover procedures , during which the UE 306 moves from a source network node , e . g . network node 304 , to a target network node , and thereby provide benefits such as reduced user waiting time and better responsiveness after handover procedures .
  • factory status information may be collected and analysed by the host 302 .
  • the host 302 may process audio and video data which may have been retrieved from a UE for use in creating maps .
  • the host 302 may collect and analyse real-time data to assist in controlling vehicle congestion ( e . g . , controlling traf fic lights ) .
  • the host 302 may store surveillance video uploaded by a UE .
  • the host 302 may store or control access to media content such as video , audio , VR or AR which it can broadcast , multicast or unicast to UEs .
  • the host 302 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs , location services , presentation services (such as compiling diagrams etc . from data collected from remote devices ) , or any other function of collecting, retrieving, storing, analysing and/or transmitting data .
  • a measurement procedure may be provided for the purpose of monitoring data rate , latency and other factors on which the one or more embodiments improve .
  • the measurement procedure and/or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of the host 302 and/or UE 306 .
  • sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 350 passes ; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exempli fied above , or supplying values of other physical quantities from which software may compute or estimate the monitored quantities .
  • the reconfiguring of the OTT connection 350 may include message format , retransmission settings , preferred routing etc . ; the reconfiguring need not directly alter the operation of the network node 304 .
  • Such procedures and functionalities may be known and practiced in the art .
  • measurements may involve proprietary UE signalling that facilitates measurements of throughput, propagation times, latency and the like, by the host 302.
  • the measurements may be implemented in that software causes messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection 350 while monitoring propagation times, errors, etc.
  • handover related losses may be missing data packets lost during handover procedure, e.g. due to reset of RAN lower layer protocols such as RLC and MAC/HARQ.
  • FIG. 4A illustrates data transmission from a network node 410 to a wireless device 420 in a downlink (DL) direction according to an embodiment.
  • the wireless device 420 may be any type of device that has access to (i.e., is served by) a cellular communications network by communicating wirelessly with network nodes and/or other wireless devices. Communicating wirelessly can involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air.
  • the wireless device may be a wireless end device or a UE as described with respect to the previous figures.
  • a wireless end device examples include, but are not limited to, a terminal, smart phones, mobile phones, cell phones, voice over IP (VoIP) phones, wireless local loop phones, desktop computers, personal digital assistants (PDAs) , wireless cameras, gaming consoles or devices, music storage devices, playback appliances, wearable devices, wireless endpoints, mobile stations, tablets, laptops, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , smart devices, wireless customer-premise equipment (CPE) , mobile-type communication (MTC) devices, Internet-of- Things (IoT) devices, vehicle-mounted wireless terminal devices , etc .
  • the term “wireles s device” or “wireless end device” is used interchangeably herein with the term “UE” or “terminal” .
  • the network node 410 may be a network node as previously described with respect to the previous figures or a radio network node which is any node that is part of the radio access network of a cellular communications network .
  • a network node is equipment capable , configured, arranged, and/or operable to communicate directly or indirectly with a wireless device and/or with other network nodes or equipment in the cellular communications network, to enable and/or provide wireless access to the wireless device , and/or to perform other functions ( e . g . , administration) in the cellular communications network .
  • the network node may be a gNodeB, gNB, or the like .
  • the network node 410 may transmit data packets to the wireless device 420 .
  • the wireless device 420 may send, to the network node 410 , acknowledgments (ACKs ) corresponding to the correctly received data packets .
  • ACKs acknowledgments
  • Correctly and success fully received data packets may be data packets which have been received without errors , for example .
  • the wireless device 420 may refrain from sending ACKs .
  • the wireless device 420 may send non-acknowledgements (NACKs ) to the network node 410 instead of ACKs or may send neither ACKs nor NACKs .
  • NACKs non-acknowledgements
  • the network node 110 may be triggered to retransmit the data packets for which no ACK has been received .
  • FIG . 4B illustrates data transmission from the wireless device 420 to the network node 410 in an uplink (UL ) direction according to an embodiment .
  • the wireless device 420 may transmit data packets to the network node 410 .
  • the network node 410 may send, to the wireless device 420 , ACKs corresponding to the correctly received data packets . I f the network node 410 does not receive any data packet or i f the network node 410 receives a data packet with errors , the network node 410 refrains from sending an ACK to the wireless device 120 .
  • the network node 410 may send a NACK instead of ACK to the wireless device 420 or may send neither NACK nor ACK .
  • the wireless device 420 may triggered to retransmit the data packet .
  • the ACK and NACK feedback can be implemented by Hybrid Automatic Repeat Request , HARQ, of e . g . the 5G or 6G physical layer .
  • FIG . 5 illustrates a receiving data link layer protocol entity 520 and a receiving higher layer transport protocol entity 510 for performing the functions of a receiving side 500 of data packets according to an embodiment .
  • the receiving side 500 may comprise the wireless device 420 .
  • the receiving side 500 may comprise the network node 410 and/or a core network node .
  • the wireless device 420 may comprise the receiving data link layer protocol entity 520 and the receiving higher layer transport protocol entity 510 , wherein the wireless device 420 may receive packets from the network in DL transmission .
  • the two entities 510 and 520 do not need to be both placed within a single wireless device 420 but may be placed in more than one wireless device and thus placed in di f ferent locations .
  • the wireless device 420 may be a smart watch and a small pocket device , wherein the receiving higher layer transport protocol entity 510 and the receiving data link layer protocol entity 520 may be divided between the smart watch and the small pocket device .
  • the receiving data link layer protocol entity 510 and the receiving higher layer transport protocol entity 510 may be in separate nodes .
  • the network node like a radio network node , e . g . a gNB, may comprise receiving RAN layer protocol entities and a receiving data link layer protocol entity 520 .
  • the data link layer protocol performed by the receiving data link layer protocol entity 520 may be PDCP .
  • the protocol may be called di f ferently .
  • the network node 410 may receive packets in an UL transmission from the wireless device 420 .
  • the receiving higher layer transport protocol entity might not be in the core network but outside of the telecommunication network, i . e . outside of the RAN or core network .
  • the receiving higher layer transport protocol entity is executed by a server somewhere in the internet or data-network .
  • the core network node may comprise the receiving data link layer protocol entity which may perform PDCP or any other data link layer protocol .
  • the network node like gNB, as separate node may comprise the RAN layer protocol entities , wherein the core network node may receive the packets in an UL transmission from the wireless device or network node , like gNB .
  • the receiving higher layer transport protocol entity might not be in the core network but outside of the telecommunication network, i . e . RAN or core network .
  • the receiving higher layer transport protocol entity is executed by a server somewhere in the internet or data- network .
  • the receiving data link layer protocol entity 520 and optionally the receiving higher layer transport protocol entity 510 may perform the functions of the respective protocol layers of the receiving side 500 .
  • a data link layer protocol entity or higher layer transport protocol entity may represent a logical instance .
  • the receiving data link layer protocol entity 520 and the receiving higher layer transport protocol entity 510 may each be loadable into respective hardware which may use respective software to implement the functions of the entities 510 and 520 .
  • a hardware device has a processor and optionally a memory .
  • the protocol entities 520 and optionally 510 are , as logical instances , loadable into the processor so that the hardware device performs the actions provided by the protocol entities 510 and 520 .
  • FIG . 14 shows an example of the respective hardware which may use software to implement the functions described herein .
  • the hardware device 1400 may comprise a processor 1410 and, optionally, an interface 1420 and/or a memory 1430 .
  • the receiving data link layer protocol entity 520 may perform the functions of a lower protocol layer of the receiving side 500 compared to the receiving higher layer transport protocol entity 510 which may perform the functions of a higher protocol layer of the receiving side 500 .
  • the receiving data link layer protocol entity 520 may be located in the data link layer of the receiving side 500 and may perform the functions of the data link layer .
  • the receiving data link layer protocol entity 520 is a receiving PDCP entity performing the functions of the PDCP sub-layer of the receiving side 500 .
  • the receiving higher layer transport protocol entity 510 may be located in the transport layer of the receiving side 500 and may perform the functions o f the transport layer .
  • the receiving higher layer transport protocol entity 510 is a receiving transport protocol entity located in the transport layer which may use the protocols TCP or QUIC .
  • the receiving side 500 may receive data packets transmitted from a transmitting node (not shown) .
  • the receiving side 500 may comprise the wireless device 420 and the transmitting node may be the network node 410 for DL transmis sion .
  • the receiving side 500 may comprise the network node 410 and/or core network node and the transmitting node may be the wireless device 420 .
  • the data packets received may be delivered from the lower layers to the higher layers using corresponding receiving protocol entities .
  • the receiving data link layer protocol entity 520 may receive the data packets from receiving lower layer protocol entities and may deliver the data packets to the receiving higher layer transport protocol entity 510 .
  • the receiving data link layer protocol entity 520 may be the receiving PDCP entity which receives the data packets from receiving RAN lower layer protocol entities .
  • the receiving PDCP entity may deliver the data packets to the receiving transport protocol entity as example of the receiving higher layer transport protocol entity 510 .
  • the receiving higher layer transport protocol entity 510 may deliver ACKs to the receiving lower layer protocol entities which may then transmit the ACKs to the transmitting node . These ACKs are used to acknowledge the correct and success ful reception of the data packets .
  • the receiving higher layer transport protocol entity 510 may deliver the ACKs to the receiving data link layer protocol entity 520 which may then deliver the ACKs to the receiving lower layer protocol entities of the receiving side 500 .
  • FIG . 6 illustrates a transmitting data link layer protocol entity 620 and a transmitting higher layer transport protocol entity 610 performing the functions of a transmitting side 600 of the communication .
  • the transmitting side 600 may comprise the network node 410 and/or a core network node .
  • the transmitting side 600 may comprise the wireless device 420 .
  • the wireless device 420 may comprise the transmitting data link layer protocol entity 620 and the transmitting higher layer transport protocol entity 610 .
  • the two entities 610 and 620 do not need to be both placed in a single wireless device 420 but may be placed in more than one wireless device ( see also the example given with respect to FIG . 5 ) .
  • the transmitting data link layer protocol entity 620 and the transmitting higher layer transport protocol entity 610 may be in separate nodes .
  • the network node like a gNB, may comprise transmitting RAN layer protocol entities and a transmitting data link layer protocol entity 620 .
  • the transmitting higher layer transport protocol entity 610 might not be in the core network but outside of the telecommunication network, i . e . RAN or core network .
  • the transmitting higher layer transport protocol entity 610 is executed by a server somewhere in the internet or data-network .
  • the core network node may comprise the transmitting data link layer protocol entity 620 which may perform PDCP or any other data link layer protocol .
  • the network node may comprise the RAN layer protocol entities , wherein the core network node may transmit the packets in an DL transmission to the wireless device or network node , like gNB .
  • the transmitting higher layer transport protocol entity 610 might not be in the core network but outside of the telecommunication network, i . e . RAN or core network .
  • the transmitting higher layer transport protocol entity 610 is executed by a server somewhere in the internet or data-network .
  • the transmitting data link layer protocol entity 620 and the transmitting higher layer transport protocol entity 610 may perform the functions of the respective layers , i . e . may perform the protocols of the respective layers .
  • the transmitting data link layer protocol entity 620 and the transmitting higher layer transport protocol entity 610 may each be loadable into respective hardware which may use respective software to implement the functions of the entities 610 and 620 .
  • a hardware device has a processor and optionally a memory .
  • the protocol entities 620 and optionally 610 as logical instances are loadable so that the hardware device performs the actions provided by the protocol entities 610 and 620 . Please refer to FIG . 14 for an example of a hardware device .
  • the transmitting data link layer protocol entity 620 may perform the functions of a lower layer of the transmitting side 600 compared to the transmitting higher layer transport protocol entity 610 which may perform the functions of a higher layer of the transmitting side 600 .
  • the transmitting data link layer protocol entity 620 may perform the functions of the data link layer of the transmitting side 600 .
  • the transmitting data link layer protocol entity 620 is a transmitting PDCP entity performing the functions of the PDCP sub-layer of the transmitting side 600 .
  • the transmitting higher layer transport protocol entity 610 may perform the functions of the transport layer of the transmitting side 600 .
  • the transmitting higher layer transport protocol entity 610 is a transmitting transport protocol entity performing the functions of the transport layer .
  • the transmitting transport protocol entity may perform TCP or QUIC .
  • the data packets transmitted by the transmitting side 600 to the receiving side 500 as exemplary illustrated in FIG . 5 may be delivered from the higher layers to the lower layers using corresponding transmitting protocol entities .
  • the transmitting higher layer transport protocol entity 610 may deliver the data packets to the transmitting data link layer protocol entity 620 which may then deliver the data packets to transmitting lower layer protocol entities (not shown) .
  • the data packets are transmitted to the receiving side 500 .
  • the transmitting PDCP entity 620 may receive the data packets from the transmitting transport protocol entity 610 .
  • the transmitting PDCP entity 620 may deliver the data packets to transmitting RAN lower layer protocol entities which may then transmit the data packets to the receiving side 500 .
  • the transmitting side 600 may receive ACKs from the receiving side 500 .
  • the transmitting lower layer protocol entities may deliver the ACKs to the transmitting data link layer protocol entity 620 which may then deliver the ACKs to the transmitting higher layer transport protocol entity 610 to acknowledge the correct and success ful reception of the data packets .
  • FIG . 7 illustrates a system overview 700 with higher layer transport protocol entities and data link layer protocol entities of a transmitting side 600 and a receiving side 500 according to an embodiment .
  • the transmitting side 600 and the receiving side 500 have been described in detail with respect to FIGs . 5 and 6 .
  • FIG . 7 exemplary shows the interaction between the entities of the transmitting node 600 and the entities of the receiving node 500 when the transmitting node 600 transmits data packets to the receiving node 500 and the receiving node 500 transmits ACKs to the transmitting node 600 i f success fully receiving the data packets .
  • the transmitting higher layer transport protocol entity 610 of the transmitting side 600 may deliver data packets to the transmitting data link layer protocol entity 620 .
  • the transmitting data link layer protocol entity 620 may deliver the data packets to transmitting lower layer protocol entities (not shown) which may transmit the data packets to the receiving entities of the receiving side 500 .
  • receiving lower layer protocol entities may receive the data packets from the transmitting lower layer protocol entities and may deliver the data packets to the receiving data link layer protocol entity 520 .
  • the receiving data link layer protocol entity 520 may deliver the data packets to the receiving higher layer transport protocol entity 510 .
  • the receiving higher layer transport protocol entity 510 may deliver an ACK corresponding to the success fully received data packet to the receiving data link layer protocol entity 520 .
  • the receiving data link layer protocol entity 520 may deliver the ACK to receiving lower layer protocol entities which may then transmit the ACK to the transmitting lower layer protocol entities of the transmitting side 600 .
  • the transmitting lower layer protocol entities may deliver the ACK to the transmitting data link layer protocol entity 620 which may then deliver the ACK to the transmitting higher layer transport protocol entity 610 .
  • the transmitting higher layer transport protocol entity 610 may learn or determine that the data packet corresponding to the ACK has been success fully received by the receiving side 500 and no retransmission of the data packet is required .
  • the transmitting higher layer transport protocol entity 610 may assume that the data packet was lost and may retransmit the data packet to the receiving side 500 .
  • the transmitting higher layer transport protocol entity 610 may assume that the data packet was lost and may retransmit the data packet to the receiving side 500 .
  • FIG . 8 illustrates an exemplary system overview 800 with transport protocol entities as higher layer protocol entities and PDCP entities as data link layer protocol entities of a transmitting side 1000 and a receiving side 900 of a communication .
  • the transmitting side 1000 and the receiving side 900 are similar to the transmitting side 600 and the receiving side 500 described with respect to Figs . 5 to 7 .
  • a detailed description about how data packets and ACKs are transmitted between the transmitting side 1000 and the receiving side 900 is omitted at this point for conciseness reasons .
  • the transmitting side 1000 may comprise a transmitting transport protocol entity 1010 which acts as transmitting higher layer transport protocol entity described above .
  • the transmitting transport protocol entity 1010 may perform TCP or QUIC .
  • the transmitting side 1000 may comprise a transmitting PDCP entity 1020 acting as transmitting data link layer protocol entity described above and transmitting RAN lower layer protocol entities 1030 .
  • the transmitting RAN lower layer protocol entities may introduce out-of-order delivery with the introduction of hybrid automatic repeat request (HARQ) .
  • HARQ hybrid automatic repeat request
  • the receiving side 900 may comprise a receiving transport protocol entity 910 which acts as receiving higher layer transport protocol entity described above .
  • the receiving transport protocol entity 910 may perform TCP or QUIC .
  • the receiving side 900 may comprise a receiving PDCP entity 920 acting as receiving data link layer protocol entity described above .
  • the receiving PDCP entity 920 may optionally perform re-ordering of the received data packets .
  • the receiving side 900 may comprise receiving RAN lower layer protocol entities 930 which may introduce out-of-order delivery with the introduction of HARQ .
  • the transmitting transport protocol entity 1010 may be in a server, and the entities 1020 and 1030 may be included in a network node , like a gNB .
  • the transmitting PDCP entity 1020 may be included in a core network node and the transmitting RAN lower layer protocol entities 1030 may be included in the network node .
  • the receiving side 900 may comprise a single wireless device where all entities 910 , 920 , and 930 are integrated into the single wireless device .
  • the wireless device comprises more than one device where , for example the entity 910 may be part of a smart watch or the like and the entities 920 and 930 may be part of a UE or smartphone .
  • the transmitting side 1000 may comprise a single wireless device where all entities 1010 , 1020 , and 1030 are integrated into the single wireless device .
  • the wireless device comprises more than one device where , for example the entity 1010 may be part of a smart watch or the like and the entities 1020 and 1030 may be part of a UE or smartphone .
  • the receiving transport protocol entity 910 may be in a server, and the entities 920 and 930 may be included in a network node , like a gNB .
  • the transmitting PDCP entity 920 may be included in a core network node and the transmitting RAN lower layer protocol entities 930 may be included in the network node .
  • transport protocols and their congestion control algorithms executed by the higher layer protocol entities have to identi fy congestion on the transport connection to be able to adj ust the number of packets brought into flight and to avoid further congestion . This is done by observing packet reordering, i . e . number and time of packets received after a missing packet .
  • the transmitting higher layer transport protocol entity executing the transport protocol may get this information based on ACKs received from the receiving higher layer transport protocol entity .
  • problems may occur for handover procedures which ensure that a wireless device is trans ferred from a source network node serving a source cell to a target network node serving a target cell .
  • packets which have not yet been transmitted are lost .
  • the receiving data link layer protocol entity does not have any packets in its receive queue that it could deliver to the receiving higher layer transport protocol entity upon/after handover . Since the receiving higher layer transport protocol entity does not receive any data packets , the receiving higher layer transport protocol entity does not deliver any ACKs to the receiving lower layer protocol entities for transmitting the ACKs to the transmitting higher layer transport protocol entity .
  • the transmitting higher layer transport protocol entity is waiting for ACKs after a missing data packet and stops transmitting new data packets into the network . Only after expiry of a (potentially long-running) recovery timer, the transmitting higher layer transport protocol entity may attempt to retransmit packets , resulting in large and unnecessary delays . Furthermore , the transmitting higher layer transport protocol entity may set its congestion window to a very small value , such that the subsequent transmission after handover might not get up to speed .
  • the idea is to re-deliver one or several packets from the receiving data link layer protocol entity to the receiving higher layer transport protocol entity .
  • the receiving data link layer protocol entity and the receiving higher layer transport protocol entity may be operating for, i . e , perform the functions of a wireless device for DL transmission, or a network device and/or core network node for UL transmission .
  • the receiving higher layer transport protocol entity may be triggered to react and send ACKs to the transmitting higher layer transport protocol entity which in turn may trigger further data packet transmissions .
  • alternative recovery mechanisms in transport protocol implementations like connection probing and delayed ack transmission ( overhead i f frequent , delay i f infrequent ) , are avoided .
  • FIG . 9 illustrates an exemplary method performed by a receiving data link layer protocol entity for triggering further data packet transmissions .
  • the method may be triggered when no handover related retransmissions of lost data during the handover in RAN ( e . g . no PDCP-like protocol ) and/or no buf fer forwarding from source network node to target network node is foreseen .
  • Optional steps are shown with dashed lines .
  • the receiving data link layer protocol entity may be a receiving PDCP entity for RAN layers .
  • the receiving PDCP entity may be loadable into hardware which may use respective software for executing the functions of the PDCP sub-layer .
  • the receiving data link layer protocol entity may delivery ( S910 ) a plurality of data packets to a receiving higher layer transport protocol entity .
  • the receiving higher layer transport protocol entity may be a receiving transport protocol entity for RAN protocol layers .
  • the receiving transport protocol entity may use TCP or QUIC .
  • the receiving transport protocol entity may be loadable into hardware which may use respective software for executing the functions of the transport layer .
  • the receiving transport protocol entity is part of the mobile network, which can be an in-network TCP or QUIC entity or proxy entity, e . g .
  • the receiving data link layer protocol entity may re-deliver ( S 930 ) a selected number of lastly delivered data packets among the plurality of data packets to the receiving higher layer transport protocol entity a certain number of times during a handover procedure .
  • the selected number of the lastly delivered data packets may be predetermined or preselected before performing a handover procedure .
  • the expression "during a handover procedure” may be understood as "part of the handover procedure .
  • the receiving data link layer protocol entity may store ( S 920 ) the selected number of the lastly delivered data packets before re-delivering them to the higher layer transport protocol entity .
  • the lastly delivered data packets may be the data packets among the plurality of data packets which have been lastly delivered in time to the receiving higher layer transport protocol entity .
  • the receiving data link layer protocol entity may use a storage entity for storing, saving, or remembering the data packets .
  • the storage entity may be a memory which is part of the receiving node , or which is a separate entity from the receiving node .
  • the idea is to trigger a reaction of the receiving higher layer transport protocol entity to transmit ACKs , i . e . a transport protocol reaction, by duplicating previously data packet deliveries from the receiving data link layer protocol entity, such as the receiving PDCP entity for RAN .
  • the selected number of lastly delivered data packets may be operated in a wireless device , such as a UE or terminal , for DL transmission or may be operated in a network node , such as a gNB, and/or core network node for UL transmission .
  • the receiving data link layer protocol entity and the receiving higher layer transport protocol entity may perform functions of the wireless device , the network node and/or the core network node .
  • the receiving data link layer protocol entity may receive data packets 1 , 2 , and 3 ( DPI , DP2 , and DP3 ) before a handover procedure over a time t .
  • DPI , DP2 , and DP3 may be delivered to the receiving higher layer transport protocol entity .
  • the receiving data link layer protocol entity may perform storing of a selected number X of lastly delivered data packets among the plurality of data packets DPI , DP2 , and DP3 which have been delivered to the receiving higher layer transport protocol entity .
  • the receiving data link layer protocol entity is able to remember or save the X lastly delivered data packets .
  • the selected number X of lastly delivered data packets is set to 1 .
  • the receiving data link layer protocol entity may perform storing of the lastly delivered data packet DP3 .
  • X can be any positive integer .
  • X > 1 may be advantageous when multiple TCP flows are multiplexed in a PDCP buf fer .
  • the receiving data link layer protocol entity may perform storing of the two lastly delivered data packets DP2 and DP3 .
  • the receiving data link layer protocol entity may re-deliver these stored, i . e . remembered or saved, X data packets a certain number o f times Y to the receiving higher layer transport protocol entity .
  • Y is set to 3 , but Y can be set to any positive integer .
  • Y > 1 may be advantageous to be resistant against ACKs losses .
  • DP3 is redelivered three times to the receiving higher layer transport protocol entity .
  • the transmission of duplicate ACKs from the receiving higher layer transport protocol entity to the transmitting higher layer transport protocol entity is triggered .
  • the receiving higher layer transport protocol entity obtains a data packet below an upper window edge again, i . e . obtains a duplicate data packet
  • the receiving higher layer transport protocol entity immediately sends a duplicate ACK, even though a delayed ACK timer is running, as the duplicate received data packet is considered reordered .
  • the receiving higher layer transport protocol entity may immediately send the duplicate ACK, because it assumes that a data packet loss has been identi fied .
  • the receiving higher layer transport protocol entity may send duplicate Acks in response to the re-delivered selected number of the lastly delivered data packets before a delayed ACK timer is elapsed, resulting in fast and immediate recovery from a handover procedure .
  • the duplicate ACKS in contrast to selective ACKs ( sACKs ) , may trigger at the transmitting higher layer transport protocol entity a retransmission of all the data packets for which ACKs has not yet been received by the transmitting higher layer transport protocol entity .
  • the transmitting higher layer transport protocol entity may retransmit all data packets which have not yet been ( selectively) acknowledged by the receiving higher layer transport protocol entity, even for gaps in between selectively acknowledged data packets and even for data packets above a lower transmission ( Tx ) edge , that has never been ( selectively) acknowledged or no higher ACK has been received before .
  • the transmitting higher layer transport protocol entity may interpret the duplicate ACKs as data packet losses due to congestion and may immediately reduce the congestion window .
  • the duplicate ACKs may trigger reduction of the congestion window at the transmitting higher layer transport protocol entity .
  • the duplicate ACKs may trigger the retransmission of data packets at the transmitting higher layer transport protocol entity only when the data packets were transmitted at least a certain recent ACK (RACK) round trip time (RTT ) delay before .
  • RACK recent ACK
  • RTT round trip time
  • the RACK RTT delay threshold is adaptive and may be adequately set . By waiting a certain RACK RTT delay threshold before transmitting the data packets , it is ensured that the transmitting higher layer transport protocol entity is able to dif ferentiate from potential reordering .
  • the receiving data link layer protocol entity may spread out the re-delivering of the selected number of the lastly delivered data packets in time , e . g . with 5 ms in-between deliveries .
  • the receiving data link layer protocol entity may spread out the re-delivering of the selected number of the lastly delivered data packets in time , e . g . with 5 ms in-between deliveries .
  • the receiving data link layer protocol entity may deliver the plurality of data packets in an out-of-order manner to the receiving higher layer transport protocol entity, or deliver the plurality of data packets in an in-order manner to the receiving higher layer transport protocol entity .
  • Out-of- order delivery may be performed to ensure continuous operation, lower latency, more interactivity, and less head- of-line blocking .
  • the receiving data link layer protocol entity may re-deliver the selected number of lastly delivered packets in a case where the receiving data link layer protocol entity refrains from buf fer forwarding during the handover .
  • the receiving PDCP entity may be configured to perform storing, i . e . may be conf igured to remember or save , the last X delivered packets .
  • the receiving PDCP entity may be configured to re-deliver these X packets Y times to the receiving higher layer transport protocol entity .
  • Transport protocols executed by a transmitting side of the communication may be expected to react with retransmissions of missing intermediate data packets (which have been lost during the handover procedure ) when receiving the ACKs of these duplicate delivered data packets , immediately .
  • the receiving data link layer protocol entity may refrain from buf fer forwarding during the handover procedure .
  • the receiving data link layer protocol entity may perform the re-delivering in a case where the receiving data link layer protocol entity refrains from buf fer forwarding from a source network node to a target network node during the handover procedure .
  • the receiving data link layer protocol entity may be in an unacknowledged mode (UM) or in an acknowledged mode (AM) .
  • UM unacknowledged mode
  • AM acknowledged mode
  • the receiving data link layer protocol entity may refrain from buf fer forwarding during the handover procedure .
  • UM no retransmission of lost data packets may be done in PDCP .
  • the receiving data link layer protocol entity may be the receiving PDCP entity which may perform the storing of the selected number of lastly delivered data packets and/or may re-deliver the selected number of the lastly delivered data packets during the handover, e . g . as part of a PDCP re-establishment procedure , when the handover is completed, or when connection to a target cell is established .
  • the completion of the handover may be seen as last step of the handover procedure .
  • the storing and/or re-delivering may be performed during a PDCP re-establishment procedure , i . e . at the end o f the handover procedure , upon a completion of the handover procedure , or upon a target cell establishment .
  • the PDCP reestablishment procedure may be triggered at handover .
  • the receiving PDCP entity may perform functions of a wireless device which performs the re-delivering during the PDCP re-establishment procedure , upon a completion of the handover procedure , or upon a target cell establishment .
  • the receiving data link layer protocol entity may perform the respective layer functions of the wireless device .
  • the receiving higher layer transport protocol entity may perform higher layer functions of the wireless device .
  • the receiving data link layer protocol entity and the receiving higher layer transport protocol entity perform the functions for the wireless device , i . e . operate in the wireless device .
  • the receiving data link layer protocol entity may perform the respective layer functions of the network node and/or the core network node .
  • the receiving higher layer transport protocol entity may perform higher layer functions of the network node and/or the core network node .
  • the receiving data link layer protocol entity and the receiving higher layer transport protocol entity perform the functions for the network device and/or the core network node , i . e . operate in the network device and/or the core network node .
  • the receiving data link layer protocol entity which performs the re-delivering as described above may perform the functions either of the source network node or of the target network node .
  • the receiving data link layer protocol entity may perform the re-delivering, for example , when handover is triggered for the wireless device , e . g . when a handover command sent , or when a handover success is indicated by the target network node .
  • the receiving data link layer protocol entity may operate in the target network node and may perform the re-delivering after having received the selected number of the lastly delivered data packets from the source network node .
  • the receiving data link layer protocol entity of the target network node may re-deliver the data packets to the receiving higher layer transport protocol entity of the target network node which requires that the receiving data link layer protocol entity of the source network node forwards the stored selected number of lastly delivered data packets to the receiving data link layer protocol entity of the target network node .
  • FIG . 11 illustrates an exemplary method performed by a system comprising a transmitting node on a transmitting side and a receiving node on a receiving side for triggering fast handover recovery .
  • a detailed description of the transmitting side and the receiving side is omitted at this point for conciseness reasons , and it is referred to the above given explanations .
  • Optional steps are shown with dashed lines .
  • the transmitting node may transmit a plurality of data packets to the receiving node , whereas the receiving node responds to success fully received plurality of data packets by transmitting ACKs to the transmitting node .
  • the transmitting node may use a transmitting data link layer protocol entity and a transmitting higher layer transport protocol entity .
  • the transmitting data link layer protocol entity may be a transmitting PDCP entity and the transmitting higher layer transport protocol entity may be a transmitting transport protocol entity, see the previous explanations .
  • the receiving node may use a receiving data link layer protocol entity and a receiving higher layer transport protocol entity .
  • the receiving data link layer protocol entity may be a receiving PDCP entity and the receiving higher layer transport protocol entity may be a receiving transport protocol entity, see the previous explanations .
  • the transmitting node may transmit ( S 1110 ) a plurality of data packets to the receiving node .
  • the plurality of data packets may be received ( S 1120 ) by the receiving node .
  • the receiving node in particular the receiving data link layer protocol entity, may deliver ( S 1130 ) the plurality of the plurality of data packets to the receiving higher layer transport protocol entity .
  • the receiving data link layer protocol entity re-deliver ( S 1150 ) the selected number of the lastly delivered data packets to the receiving higher layer transport protocol entity a certain number of times during a handover procedure .
  • the receiving data link layer protocol entity may store ( S 1140 ) the selected number of lastly delivered data packets before re-delivering them .
  • a storage entity such as a memory, may be used which stores the selected number of lastly delivered data packets .
  • the receiving higher layer transport protocol entity of the receiving side may send, to the transmitting side , in particular the transmitting higher layer transport protocol entity, duplicate ACKs in response to the re-delivered selected number of the lastly delivered data packets before a delayed ACK timer is elapsed .
  • the transmitting higher layer transport protocol entity may retransmit , to the receiving side , data packets for which ACKs have not yet been received by the transmitting higher layer transport protocol entity .
  • fast handover recovery is achieved .
  • FIG . 12 illustrates an exemplary configuration for a receiving node 1200 .
  • the receiving node 1200 may be a wireless device for receiving a DL transmission from a network, or a network node and/or core network node for receiving an UL transmission from a wireless device .
  • the receiving node 1200 may comprise a processing unit 1210 and a communication interface .
  • the receiving node 1200 comprises a transmitting unit 1220 and a receiving unit 1230 for communicating with a transmitting node .
  • the receiving node 1200 may further comprise a memory which may also be referred to as storage unit or storage entity (not shown) .
  • the processing unit 1210 may be a processing circuitry (which may also be referred to as control circuitry) and may also be called a processor . Any module or unit of the receiving node 1200 may be implemented in and/or executable by, the processing unit 1210 , in particular as module in the processing unit 1410 .
  • the receiving data link layer protocol entity may be loadable into the processing unit 1410 .
  • the receiving node 1200 is a wireless device , such as a UE or terminal
  • the receiving data link layer protocol entity and the higher layer transport protocol entity may be loadable into the processing unit 1410 .
  • the receiving data link layer protocol entity may be loadable into the processing unit 1410 .
  • the higher layer transport protocol entity might not be loaded into the processing unit 1410 , but may be loadable into a server or host outside of the telecommunication network (RAN or core network) , e . g . into a server somewhere in the internet or data-network .
  • the transmitting unit 1220 and the receiving unit 1230 may be radio circuitry providing receiving and transmitting or transceiving functionality, e . g . one or more transmitters and/or receivers and/or transceivers , wherein the radio circuitry is connected or connectable to the processing unit 1210 .
  • An antenna circuitry (not shown) of the receiving node 1200 may be connected or connectable to the radio circuitry to collect or send and/or ampli fy signals .
  • the data packets transmitted by the transmitting node may be received using the receiving unit 1230 .
  • the transmitting unit 1220 may be used for transmitting the ACKs ( selective and/or duplicate ACKs ) to the transmitting node .
  • the receiving node 1200 may be adapted to carry out any of the methods described above .
  • FIG . 13 illustrates an exemplary configuration for a transmitting node 1300 .
  • the transmitting node 1300 may be a wireless device for sending an UL transmission to the network, or a network node and/or core network node for sending a DL transmission to the wireless device .
  • the transmitting node 1300 may comprise a processing unit 1310 and a communication interface .
  • the transmitting node 1300 comprises a transmitting unit 1320 and a receiving unit 1330 for communicating with a receiving node .
  • the transmitting node 1300 may further comprise a memory which may also be referred to as storage unit or storage entity (not shown) .
  • the processing unit 1310 may be a processing circuitry (which may also be referred to as control circuitry) and may also be called a processor . Any module or unit of the transmitting node 1300 may be implemented in and/or executable by, the processing unit 1310 , in particular as module in the processing unit 1310 .
  • the transmitting data link layer protocol entity may be loadable into the processing unit 1310 .
  • the transmitting node 1300 is a wireless device , such as a UE or terminal , the transmitting data link layer protocol entity and the higher layer transport protocol entity may be loadable into the processing unit 1310 .
  • the transmitting data link layer protocol entity may be loadable into the processing unit 1310 .
  • the higher layer transport protocol entity might not be loaded into the processing unit 1310 , but may be loadable into a server or host outside of the telecommunication network (RAN or core network) , e . g . into a server somewhere in the internet or data-network .
  • the transmitting unit 1320 and the receiving unit 1330 may be radio circuitry providing receiving and transmitting or transceiving functionality, e . g . one or more transmitters and/or receivers and/or transceivers , wherein the radio circuitry is connected or connectable to the processing unit 1310 .
  • An antenna circuitry (not shown) of the transmitting node 1300 may be connected or connectable to the radio circuitry to collect or send and/or ampli fy signals .
  • the data packets may be transmitted using the transmitting unit 1320 .
  • the receiving unit 1320 may be used for receiving the ACKs ( selective and/or duplicate ACKs ) from the receiving node .
  • the transmitting node 1300 may be adapted to carry out any of the methods described above .
  • the transmitting node and the receiving node described herein may also be implemented as a hardware device 1400 as exemplary shown in FIG . 14 .
  • FIG . 15 illustrates simulation results using the herein described method for fast handover recovery according to an embodiment .
  • the obj ect bitrate of 10MB file download over a l O OMbit/ s channel with HARQ and 10% block error rate (BLER) target is shown over time t in ms .
  • the umooo-line shows results of PDCP unacknowledged mode with out-of-order deliver .
  • the umoooDeliverAgainO-3-line shows results of PDCP unacknowledged mode with out-of-order deliver where no data packets are lost and buf fer forwarding is performed .
  • Duplicate delivery ( three times after the handover ) of last downlink TCP data packets is performed in the receiving PDCP entity . Since in this case the same results as for the baseline (umooo-line ) are achieved, the umooo-line and the umoooDeliverAgainO-3-line overlap each other in the diagram of FIG . 15 .
  • the umoooNoHoForward-line shows results of PDCP unacknowledged mode with out-of-order delivery but without handover buf fer forwarding .
  • the umoooNoHoForwardDeliverAgainO-3-line shows results of PDCP unacknowledged mode with out-of-order delivery but without handover buf fer forwarding .
  • the above described method for storing and re-delivering of the selected number of the lastly delivered data packets Y number of times during the handover procedure is performed, wherein Y is set to 3 .
  • FIG . 16 illustrates further simulation results using the herein described method for fast handover recovery .
  • the same settings as in FIG . 15 have been used, wherein handover during the slowstart phase of TCP download is shown .
  • the umoooNoHoForwardDeliveryAgainO-3-line which is close to the umooo-baseline and the umoooDeliverAgainO-3-line .
  • the umoooNoHoForward-line highlights that performing neither buf fer forwarding nor the above-described method results in poor performance .
  • FIGs illustrates further simulation results using the herein described method for fast handover recovery .
  • the same settings as in FIG . 15 have been used, wherein handover during the slowstart phase of TCP download is shown .
  • 15 and 16 show that very good performances and fast handover recovery can be achieved when executing the above-described method in the receiving data link layer protocol entity, i . e . when triggering duplicate ACKs by storing and re-delivering a selected number of lastly delivered data packets a certain number of times .
  • a computer program product comprising instructions adapted for causing processing and/or control circuitry to carry out and/or control any method described herein with regard to the receiving/ transmitting data link layer protocol entity, the receiving/ transmitting higher layer transport protocol entity, the wireless device , and the network node , in particular when executed on the processing and/or control circuitry .
  • a carrier medium arrangement carrying and/or storing a computer program product as described herein .

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne des procédés pour une entité de protocole de couche de liaison de données de réception, telle qu'une entité de protocole de convergence de données par paquets (PDCP) de réception, pour une récupération de transfert rapide. Un procédé, mis en œuvre par l'entité de protocole de couche de liaison de données de réception, comprend l'étape de distribution d'une pluralité de paquets de données à une entité de protocole de transport de couche supérieure de réception. En outre, le procédé comprend les étapes consistant à redistribuer un nombre sélectionné de paquets de données délivrés en dernier parmi la pluralité de paquets de données à l'entité de protocole de transport de couche supérieure de réception un certain nombre de fois pendant une procédure de transfert intercellulaire.
PCT/EP2023/052155 2023-01-30 2023-01-30 Récupération rapide à partir d'un transfert avec un mode de distribution irrégulière Ceased WO2024160341A1 (fr)

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CN202380092027.5A CN120604481A (zh) 2023-01-30 2023-01-30 从具有乱序递送的切换中快速恢复
PCT/EP2023/052155 WO2024160341A1 (fr) 2023-01-30 2023-01-30 Récupération rapide à partir d'un transfert avec un mode de distribution irrégulière
EP23702574.7A EP4659392A1 (fr) 2023-01-30 2023-01-30 Récupération rapide à partir d'un transfert avec un mode de distribution irrégulière

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US20090086676A1 (en) * 2007-09-28 2009-04-02 Qualcomm Incorporated Methods for intra base station handover optimizations
KR20110036953A (ko) * 2008-07-31 2011-04-12 콸콤 인코포레이티드 무선 통신 시스템에서 핸드오버 동안에 데이터 손실을 감소시키기 위한 방법 및 장치

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