Traffic delivery in user equipment-to-network relay scenarios

Abstract

Embodiments of the present disclosure relate to traffic delivery in a user equipment (UE)-to-network (U2N) relay scenario. A central unit of a first network device sends a request to a central unit of a second network device to communicate traffic between a remote terminal device and the central unit of the first network device using a distributed unit of the second network device and a relay terminal device. The first network device and the second network device are a main node and an auxiliary node of the relay terminal device. In turn, the central unit of the first network device receives a response from the central unit of the second network device, the response includes information for the central unit of the first network device to send traffic of the remote terminal device to the relay terminal device via the distributed unit of the second network device or to receive traffic of the remote terminal device from the relay terminal device.

Description

Technical Field

[0001] Various example embodiments relate to the field of telecommunications, and in particular to methods, devices, apparatuses, and computer-readable storage media for traffic delivery in a User Equipment (UE) to Network (U2N) relay scenario. Background Art

[0002] Sidelink (SL) relays are introduced to support U2N relay functions to provide U2N remote UEs with connectivity to the network. In addition, with the development of communication technology, a new network architecture has been developed to split the functions of base stations in the radio access network to increase deployment flexibility. Some functions of the base station are deployed on the central unit (CU), while other functions are deployed on the distributed unit (DU). For example, the CU can be responsible for some high-level protocol stack functions, and the DU can be responsible for low-level protocol stack functions.

[0003] In addition, a technology called multi-radio dual connectivity (MR-DC) is also supported. Using MR-DC, a UE in a connected state is configured to utilize radio resources provided by two different schedulers, which are located in two different network nodes (referred to as the primary network node and the secondary network node, respectively), which are connected via a non-ideal backhaul, one network node providing new radio (NR) access, and the other network node providing evolved universal terrestrial radio access (E-UTRA) or NR access. MR-DC is a key enabler for fifth-generation (5G) networks and beyond. When the UE is connected to multiple network nodes at the same time, communication efficiency can be improved. However, in U2N relay scenarios, the utilization of MR-DC needs to be studied and developed. Summary of the invention

[0004] In general, example embodiments of the present disclosure provide a solution for traffic delivery in a U2N relay scenario.

[0005] In a first aspect, a central unit of a first network device is provided. The central unit of the first network device includes at least one processor and at least one memory storing instructions, and when the instructions are executed by the at least one processor, the central unit of the first network device at least: sends a request to the central unit of a second network device to transmit services between a remote terminal device and the central unit of the first network device using a distributed unit and a relay terminal device of the second network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and receives a response from the central unit of the second network device, the response including information for the central unit of the first network device to send services of the remote terminal device to the relay terminal device or to receive services of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0006] In a second aspect, a central unit of a second network device is provided. The central unit of the second network device includes at least one processor and at least one memory storing instructions, and when the instructions are executed by the at least one processor, the central unit of the second network device at least: receives a request from the central unit of the first network device to transmit services between a remote terminal device and the central unit of the first network device using a distributed unit of the second network device and a relay terminal device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and sends a response to the central unit of the first network device, the response including information for the central unit of the first network device to send services of the remote terminal device to the relay terminal device or receive services of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0007] In a third aspect, a distributed unit of a second network device is provided. The distributed unit of the second network device includes at least one processor and at least one memory storing instructions, and when the instructions are executed by the at least one processor, the distributed unit of the second network device at least: receives a request from the central unit of the second network device to use a relay terminal device to transmit a service of a remote terminal device between the remote terminal device and the central unit of a first network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; determines a configuration for transmitting the service based on the request; and sends the configuration to the central unit of the second network device.

[0008] In a fourth aspect, a relay terminal device is provided. The distributed unit of the second network device includes at least one processor and at least one memory storing instructions, and when the instructions are executed by the at least one processor, the relay terminal device at least: receives a configuration message from the central unit of the first network device or the central unit of the second network device, and the configuration message is used to configure the relay terminal device for mapping of services of the remote terminal device to be relayed by the relay terminal device between the following items: a first communication channel between the relay terminal device and the remote terminal device; and a second communication channel between the distributed unit of the second network device and the relay terminal device, and wherein the first network device and the second network device are the primary node and the secondary node of the relay terminal device.

[0009] In a fifth aspect, a method implemented at a central unit of a first network device is provided. The method includes sending a request to a central unit of a second network device to transmit a service between a remote terminal device and the central unit of the first network device using a distributed unit of the second network device and a relay terminal device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and receiving a response from the central unit of the second network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device or to receive the service of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0010] In a sixth aspect, a method implemented at a central unit of a second network device is provided. The method includes receiving a request from a central unit of a first network device to transmit a service between a remote terminal device and the central unit of the first network device using a distributed unit of the second network device and a relay terminal device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and sending a response to the central unit of the first network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device or to receive the service of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0011] In a seventh aspect, a method implemented at a distributed unit of a second network device is provided. The method includes receiving a request from a central unit of the second network device to use a relay terminal device to transmit a service of a remote terminal device between the remote terminal device and a central unit of a first network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; determining a configuration for transmitting the service based on the request; and sending the configuration to the central unit of the second network device.

[0012] In an eighth aspect, a method implemented at a relay terminal device is provided. The method includes receiving a configuration message from a central unit of a first network device or a central unit of a second network device, the configuration message being used to configure the relay terminal device for mapping of services of a remote terminal device to be relayed by the relay terminal device between: a first communication channel between the relay terminal device and the remote terminal device; and a second communication channel between a distributed unit of the second network device and the relay terminal device, and wherein the first network device and the second network device are a primary node and a secondary node of the relay terminal device.

[0013] In a ninth aspect, a device is provided. The device includes a component for sending a request for transmitting a service between a remote terminal device and the central unit of the first network device using a distributed unit of the second network device and a relay terminal device at a central unit of a first network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and a component for receiving a response from the central unit of the second network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device or to receive the service of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0014] In a tenth aspect, a device is provided. The device includes a component for receiving, at a central unit of a second network device, a request for transmitting a service between a remote terminal device and the central unit of the first network device using a distributed unit of the second network device and a relay terminal device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and a component for sending a response to the central unit of the first network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device or to receive the service of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0015] In an eleventh aspect, an apparatus is provided. The apparatus includes a component for receiving, at a distributed unit of a second network device, from a central unit of the second network device, a request for using a relay terminal device to transmit a service of a remote terminal device between the remote terminal device and a central unit of a first network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; a component for determining a configuration for transmitting the service based on the request; and a component for sending the configuration to the central unit of the second network device.

[0016] In a twelfth aspect, an apparatus is provided. The apparatus includes a component for receiving a configuration message from a central unit of a first network device or a central unit of a second network device at a relay terminal device, the configuration message being used to configure the relay terminal device for mapping of services of a remote terminal device to be relayed by the relay terminal device between: a first communication channel between the relay terminal device and the remote terminal device; and a second communication channel between a distributed unit of the second network device and the relay terminal device, and wherein the first network device and the second network device are a primary node and a secondary node of the relay terminal device.

[0017] In a thirteenth aspect, a non-transitory computer-readable medium is provided, the non-transitory computer-readable medium comprising program instructions for causing an apparatus to at least execute a method according to any one of the fifth to eighth aspects above.

[0018] In a fourteenth aspect, a computer program is provided, which includes instructions, which when executed by a device cause the device to at least perform a method according to any one of the fifth to eighth aspects above.

[0019] In a fifteenth aspect, a terminal device is provided. The terminal device includes a sending circuit system configured to send a request to a central unit of a second network device to transmit a service between a remote terminal device and a central unit of a first network device using a distributed unit of the second network device and a relay terminal device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and a receiving circuit system configured to receive a response from the central unit of the second network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device or to receive the service of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0020] In a sixteenth aspect, a central unit of a second network device is provided. The central unit of the second network device includes a receiving circuit system configured to receive a request from the central unit of a first network device to transmit a service between a remote terminal device and the central unit of the first network device using a distributed unit of the second network device and a relay terminal device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and a sending circuit system configured to send a response to the central unit of the first network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device or to receive the service of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0021] In a seventeenth aspect, a distributed unit of a second network device is provided. The distributed unit of the second network device includes a receiving circuit system configured to receive a request from a central unit of the second network device to use a relay terminal device to transmit a service of a remote terminal device between the remote terminal device and the central unit of a first network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; a determining circuit system configured to determine a configuration for transmitting the service based on the request; and a sending circuit system configured to send the configuration to the central unit of the second network device.

[0022] In an eighteenth aspect, a relay terminal device is provided. A distributed unit of a second network device includes a receiving circuit system configured to receive a configuration message from a central unit of a first network device or a central unit of a second network device, the configuration message being used to configure the relay terminal device for mapping of services of a remote terminal device to be relayed by the relay terminal device between: a first communication channel between the relay terminal device and the remote terminal device; and a second communication channel between the distributed unit of the second network device and the relay terminal device, and the first network device and the second network device are a primary node and a secondary node of the relay terminal device.

[0023] It should be understood that the invention summary is not intended to identify the key or essential features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0025] Figure 1A illustrates an example environment in which example embodiments of the present disclosure may be implemented;

[0026] Figure 1B illustrates example scenarios in which some example embodiments of the present disclosure may be implemented;

[0027] Figure 1C illustrates a user plane (UP) protocol stack for a layer 2 (L2) U2N relay according to some example embodiments of the present disclosure;

[0028] Figure 1D illustrates a control plane (CP) protocol stack for L2 U2N relay according to some example embodiments of the present disclosure;

[0029] Figure 2 illustrates an example of a signaling flow according to some example embodiments of the present disclosure;

[0030] Figure 3illustrates example processes according to some example embodiments of the present disclosure;

[0031] Figure 4 illustrates a flow chart of a method implemented at a central unit of a first network device according to some embodiments of the present disclosure;

[0032] Figure 5 illustrates a flow chart of a method implemented at a central unit of a second network device according to some embodiments of the present disclosure;

[0033] Figure 6 A flowchart of a method implemented at a distributed unit of a second network device according to some embodiments of the present disclosure is illustrated;

[0034] Figure 7 A flowchart of a method implemented at a relay terminal device according to some embodiments of the present disclosure is illustrated;

[0035] Figure 8 illustrates a simplified block diagram of a device suitable for implementing some example embodiments of the present disclosure; and

[0036] Fig. 9 A block diagram illustrating an example of a computer readable medium according to some example embodiments of the present disclosure is illustrated.

[0037] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0038] The principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described only for illustrative purposes and help those skilled in the art to understand and implement the present disclosure, and do not represent any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in various other ways except for the way described below.

[0039] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0040] In this disclosure, references to "one embodiment," "an embodiment," and "an example embodiment" indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include the particular feature, structure, or characteristic. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, those skilled in the art believe that it is within the knowledge of those skilled in the art to affect such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described.

[0041] It should be understood that although the terms "first" and "second" etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the example embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0042] The term used herein is only used to describe specific embodiments, but is not intended to limit exemplary embodiments. The singular form "one", "one" and "the" used herein also include plural forms, unless the context clearly states otherwise. It is further understood that the term "includes", "comprising", "having", "having", "including" and / or "comprising" specifies the existence of the features, elements and / or components when used in this article, but does not exclude the existence or addition of one or more other features, elements, components and / or their combinations. As used in this article, "at least one of the following: <list of two or more elements>" and "at least one of the lists of <two or more elements>" and similar wording (wherein the list of two or more elements is connected by "and" or "or") refer to at least any one element in these elements, or at least any two or more elements in these elements, or at least all elements in these elements.

[0043] As used in this application, the term "circuitry" may refer to one, more, or all of the following:

[0044] (a) a pure hardware circuit implementation (such as an implementation using only analog and / or digital circuitry), and

[0045] (b) a combination of hardware circuitry and software such as (where applicable):

[0046] (i) a combination of analog and / or digital hardware circuits and software / firmware, and

[0047] (ii) any portion of hardware processor(s) (including digital signal processor(s)) with software, software and memory(s) that work together to enable a device (such as a mobile phone or server) to perform various functions), and

[0048] (c) Hardware circuits and / or processor(s), such as microprocessor(s) or portions of microprocessor(s), that require software (e.g., firmware) to operate, but which may not be present when the software is not required for operation.

[0049] This definition of circuitry applies to all uses of the term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its accompanying software and / or firmware. For example, if applicable to a particular claim element, the term circuitry also covers a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0050] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as Long Term Evolution (LTE), Advanced LTE (LTE-A), Wideband Code Division Multiplexing (WCDMA), High Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), Non-terrestrial Network (NTN), IoT on NTN, etc. In addition, the communication between the terminal device and the network device in the communication network can be performed according to any suitable generation of communication protocol, including but not limited to the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G), future sixth generation (6G) communication protocol, and / or any other protocol currently known or to be developed in the future. The embodiments of the present disclosure can be applied to various communication systems. Considering the rapid development of communication, there will certainly be communication technologies and systems that can be used to embody future types of the present disclosure. It should not be regarded as limiting the scope of the present disclosure to the above-mentioned system.

[0051] As used herein, the term "network device" refers to a node in a communication network via which a terminal device accesses the network and receives services from the network. Depending on the terminology and technology applied, a network device may refer to a base station (BS) or an access point (AP), such as a NodeB (NodeB or NB), an evolved NodeB (eNodeB or eNB), a new radio (NR) NB (also known as a gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), an integrated access and backhaul (IAB) node, a relay, a low-power node (such as a femto, a pico), etc.

[0052] The term "terminal device" refers to any terminal device capable of wireless communication. As an example and not limitation, a terminal device may also be referred to as a communication device, a user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device (such as a digital camera), a game terminal device, a music storage and playback device, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a laptop embedded device (LEE), a laptop mounted device (LME), a USB dongle, a smart device, a wireless customer premises equipment (CPE), an Internet of Things (IoT) device, a machine type communication (MTC) device, a watch or other wearable device, a head mounted display (HMD), a vehicle, a drone, medical equipment and applications (e.g., remote surgery), industrial equipment and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronic devices, equipment operating on commercial and / or industrial wireless networks, etc. In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0053] As mentioned above, SL relay is introduced to support U2N relay function to provide connection to the network for U2N remote UE. UP and CP protocol stacks of L2 U2N relay are introduced respectively. For remote UE, high-level protocols such as Uu Service Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP) and Radio Resource Control (RRC) protocol are terminated end-to-end between remote UE and New Radio (NR) NodeB (gNB). Low-level protocols such as Radio Link Control (RLC), Media Access Control (MAC) and Physical Layer (PHY) protocols are terminated in each hop between remote UE and relay UE or between relay UE and gNB. There are other protocols such as Uu Sidelink Relay Application Protocol (SRAP) between relay UE and gNB and Proximity Service (ProSe) Communication 5 (PC5) SRAP between remote UE and relay UE, which are introduced in each hop to handle the service mapping of different bearers and remote UEs. With the development of communication technology, a new network architecture has been developed to split the functions of base stations in the access network to improve the flexibility of deployment. Some functions of the base station are deployed on the CU, while other functions are deployed on the DU. For example, the CU may be responsible for some high-level protocol stack functions, and the DU may be responsible for low-level functions.

[0054] In Release 17 (Rel-17), the remote UE and L2 U2N relay UE are connected to the same gNB-CU and the same gNB-DU. For the F1 CP / UP (F1-C / U) traffic of the remote UE, in the downlink (DL) direction, the DL F1-C / U traffic of the remote UE is sent to the gNB-DU, and the gNB-DU performs DL mapping, such as mapping from the F1 user plane (F1-U) tunnel to the Uu RLC channel (CH) of the relay UE. In the uplink (UL) direction, the data radio bearer (DRB) / signaling radio bearer (SRB) traffic of the remote UE is received at the gNB-DU and then transmitted to the gNB-CU via the relevant F1-U tunnel or F1-C signaling. For example, during the F1 application protocol (F1AP) UE context establishment procedure of the remote UE and the relay UE, the gNB-DU also generates the PC5 relay RLC CH configuration for the remote UE and the relay UE.

[0055] In addition, a technique called MR-DC is also supported. With MR-DC, a UE in a connected state is configured to utilize radio resources provided by two different schedulers, which are located in two different network nodes (referred to as the primary network node and the secondary network node, respectively), which are connected via a non-ideal backhaul, one network node providing NR access and the other network node providing E-UTRA or NR access. In DC, the primary node (MN or MN-CU) decides to split the bearer, for example, using the secondary cell group (SCG) path of a certain DRB to decide to split the bearer.

[0056] In the U2N relay scenario, the relay UE can be dual connected to two gNBs, for example, to improve robustness, reliability, etc. As in Rel-17, the remote UE and the relay UE use the same gNB-DU and the same gNB-CU, and when the relay UE is in NR-DC, only the master gNB can configure the SL of the relay UE and the remote UE. In other words, PC5 can only be configured by the master gNB. This means that the master gNB-DU is used for the remote UE to generate the PC5 relay RLC CH configuration. The DL F1-U traffic of the remote UE is terminated at the master gNB-DU. Then, the DL traffic of the remote UE is sent to the relay UE via the master cell group (MCG).

[0057] Currently, even if the MCG path is congested, the SCG path of the relay UE cannot be used for the service of the remote UE, so the DC of the relay UE cannot be utilized. How to use the SCG path of the relay UE for the remote UE is still an important issue that needs to be solved.

[0058] According to an embodiment of the present disclosure, a service transmission scheme in a U2N relay scenario is provided. Through this scheme, the central unit of a first network device sends a request to the central unit of a second network device to use a distributed unit of the second network device and a relay terminal device to transmit services between a remote terminal device and the central unit of the first network device. The first network device and the second network device are a primary node and a secondary node of the relay terminal device. Subsequently, the central unit of the first network device receives a response from the central unit of the second network device, the response including information for the central unit of the first network device to send the services of the remote terminal device to the relay terminal device via the distributed unit of the second network device or to receive the services of the remote terminal device from the relay terminal device.

[0059] In this way, by transmitting the services of the terminal device via the distributed unit and the relay terminal device of the second network device, the mobility robustness and overall reliability of the network can be improved, especially when the communication channel between the distributed unit and the relay terminal device of the first network device is congested. Accordingly, the switching interruption time can be reduced, and the communication efficiency and user experience can be improved.

[0060] The principles and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Figure 1A , which illustrates an example environment 100 in which example embodiments of the present disclosure may be implemented.

[0061] Environment 100, which may be part of a communication network, includes two network devices 103 and 105, also referred to as first network device 103 and second network device 105. For example, first network device 103 and second network device 105 may communicate with each other or with other devices via each other.

[0062] like Figure 1A As shown, the first network device 103 may include a CU 110 and a DU 115, and the second network device 105 may include a CU 120 and a DU 125. For example, the DU 115 may be under the control of the CU 110, and similarly, the DU 125 may be under the control of the CU 120.

[0063] Environment 100 also includes two terminal devices 130 and 140 that communicate with each other or with other devices via each other. Terminal device 140 can communicate with network devices 103 and 105 via terminal device 130. In this case, terminal device 130 is dual-connected to two network devices 103 and 105. First network device 103 and second network device 105 are a master node (MN) and a secondary node (SN) of terminal device 130. For the purpose of discussion, terminal devices 130 and 140 will be referred to as relay terminal device 130 and remote terminal device 140, respectively.

[0064] In some example embodiments, the relay terminal device 130 may be connected to the CU 105 via the DU 110 and connected to the CU 115 via the DU 120. In some other example embodiments, the relay terminal device 130 may communicate with the CU 105 via the DU 120. For example, the terminal device 140 may communicate with the CU 110 via the DU 115 and the relay terminal device 130. Alternatively or additionally, the terminal device 140 may communicate with the CU 110 via the DU 120 and the relay terminal device 130.

[0065] It should be understood that Figure 1A The network environment 100 shown is for illustration purposes only and does not represent any limitation on the scope of the present disclosure. Figure 1A The terminal devices 130 and 140 are depicted as mobile phones, but the terminal devices 130 and 140 may be any type of user equipment.

[0066] It should be understood that Figure 1A The number of devices (ie, network devices 103 and 105, terminal devices 130 and 140) shown and their connection relationships, structures and types are for illustration purposes only and do not represent any limitation. Environment 100 may include any suitable number of devices suitable for implementing embodiments of the present disclosure.

[0067] Communications in environment 100 may follow any suitable communications standards or protocols that already exist or will be developed in the future, such as Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), Advanced LTE (LTE-A), Fifth Generation (5G) New Radio (NR), Wireless Fidelity (Wi-Fi), and Worldwide Interoperability for Microwave Access (WiMAX) standards, and employ any suitable communications technology, including, for example, Multiple Input Multiple Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM), Time Division Multiplexing (TDM), Frequency Division Multiplexing (FDM), Code Division Multiplexing (CDM), Bluetooth, ZigBee, and Machine Type Communications (MTC), Enhanced Mobile Broadband (eMBB), Massive Machine Type Communications (mMTC), Ultra-Reliable Low Latency Communications (URLLC), Carrier Aggregation (CA), Dual Connectivity (DC), and New Radio Unlicensed (NR-U) technologies.

[0068] Reference now Figure 1B , which illustrates an example scenario 150 in which some example embodiments of the present disclosure may be implemented. Figure 1BAs shown, remote UE 151 communicates with relay UE 153. Relay UE 153 is dual-connected to MN and SN. MN communicates with core network (CN) 163. MN includes MN-CU 155 and MN-DU 157, and SN includes SN-CU 159 and SN-DU 161. In some example embodiments, remote UE 151 may communicate with MN-CU 155 via MN-DU 157 and relay UE 153. In some other example embodiments, for example, if the communication channel between MN-DU 157 and relay UE 153 is congested, remote UE 151 may communicate with MN-CU 155 via SN-DU 161 and relay UE 153.

[0069] Figure 1C and Figure 1D The UP and CP protocol stacks of the L2U2N relay according to some example embodiments of the present disclosure are illustrated respectively. For the remote UE, high-layer protocols such as Uu SDAP, PDCP, and RRC protocols are terminated end-to-end between the remote UE and the NR gNB. Low-layer protocols such as RLC, MAC, and PHY protocols are terminated in each hop between the remote UE and the relay UE or between the relay UE and the gNB. In addition, some protocols such as Uu SRAP and PC5 SRAP protocols are also supported in each hop to handle the service mapping of different bearers and remote UEs.

[0070] Figure 2 An example of a signaling flow according to some example embodiments of the present disclosure is illustrated. For the purpose of discussion, reference will be made to Figure 1A The signaling flow 200 is described. The signaling flow 200 involves the CU 110 and DU 115 of the first network device 103, the CU 120 and DU 125 of the second network device 105, the relay terminal device 130, and the remote terminal device 140. The first network device 103 and the second network device 105 are the master node and the slave node of the relay terminal device 130. It should be understood that although Figure 1A The signaling flow 200 is described in the network environment 100, but the process flow can also be applied to other communication scenarios.

[0071] like Figure 2 As shown, CU 110 sends (205) a request 206 to CU 120 to transmit services between remote terminal device 130 and CU 110 using DU 125 and relay terminal device 130. For example, CU 110 may send an XnAP request message to CU 120 to request that services of remote terminal device 140 be transmitted via the SCG path of relay terminal device 130. Accordingly, CU 120 receives (210) the request 206 from CU 110.

[0072] In some example embodiments, for example, if the CU 110 determines that the communication channel (e.g., Uu relay RLC CH) between the DU 115 of the first network device 103 and the relay terminal device 130 is congested, or when the CU 110 detects that a new remote terminal device is connected and the channel (e.g., Uu relay RLCCH) between the DU 115 of the first network device 103 and the relay terminal device 130 cannot support the service of the remote terminal device, or if the CU 110 determines other scenarios in which the service of the remote terminal device can be better supported by using the SCG or DU 125, the CU 110 may determine to request the use of the DU 125 and the relay terminal device 130 to transmit the service between the CU 110 and the remote terminal device 140. In this case, by using the DU 125 to transmit the service of the remote terminal device 140, communication interruption can be effectively avoided.

[0073] In some example embodiments, the request 206 may include an identifier (ID) of the relay terminal device 130. The request 206 may also include SRAP header information, such as an ID of the remote terminal device 140, an ID of a DRB for the service, an ID of an SRB for the service, a quality of service (QoS) associated with the service, an ID of a first communication channel (e.g., a PC5 relay RLC CH) for transmitting the service between the remote terminal device 140 and the relay terminal device 130, and a QoS associated with the first communication channel, which will be used by the CU 125 to configure the relay terminal device 130 for, for example, mapping between a Uu relay RLC CH and a PC5 relay RLC CH. In this case, the PC5 relay RLC CH is still configured by the first network device 103. For example, the first network device 103 may send the configured PC5 relay RLC CH ID and the associated QoS to the second network device 105 so that the second network device 105 configures the Uu-PC5 mapping in the relay terminal device 130.

[0074] Alternatively or additionally, the request 206 may also include an index or ID of a second communication channel (e.g., a Uu relay RLC CH) required for transmitting traffic between the DU 125 and the relay terminal device 130, and a QoS associated with the second communication channel. For example, the request 206 may also include an index of a tunnel (e.g., an F1 tunnel) used for transmitting traffic between the CU 110 and the DU 125, and a QoS associated with the tunnel, which will be used by the CU 120 to determine the required Uu relay RLC CH to be established or modified between the DU 125 and the relay terminal device 130. Alternatively or additionally, the request 206 may also include a tunnel endpoint ID (TEID) of the tunnel that terminates at the CU 110, such as a UL Fully Qualified TEID (F-TEID), which will be used by the CU 120 to configure the DU 125 for forwarding UL UP traffic of the remote terminal device 130.

[0075] Then, the CU 120 may determine the required Uu relay RLC CH to be established / modified. In addition, the CU 120 sends (215) to the DU 125 an additional request 216 to use the relay terminal device 130 to transmit the traffic of the remote terminal device 140 between the CU 110 and the remote terminal device 140. For example, the CU 120 may send to the DU 125 an additional request 216 for the relay terminal device 130 for configuring the DU 125 to use the relay terminal device 130 to transmit the traffic of the remote terminal device 140. Accordingly, the DU 125 receives (220) the additional request 216 from the CU 120. For example, the additional request 216 may request DL F1-U tunnel information from the DU 125.

[0076] This is not supported in the current F1AP, which only supports DL mapping configuration (and F1-U tunnel information) for the remote terminal device 140 via UE-associated F1AP signaling. In this case, there is no context associated with the remote terminal device 140 in the CU 120, so the UE-associated F1AP signaling cannot be reused for the remote terminal device 140 to configure DL mapping and F1-U. It is necessary to introduce enhancements to the existing F1AP process or introduce new F1AP processes.

[0077] For example, a new or enhanced F1AP request message may be used to configure the DU 125 to support the services of the remote terminal device 140 via the SCG path of the relay terminal device 130. In another example, the CU 120 may initiate UE-associated F1AP signaling for the relay terminal device 130 to configure the DU 125 to support the services of the remote terminal device 140 via the SCG path of the relay terminal device 130. In this case, an F1 procedure may be initiated for the relay terminal device 130 to establish an F1-U tunnel, a Uu relay RLC CH, and mappings therebetween. In this case, no DRB is established, and thus the F1-U tunnel is established without DRB establishment.

[0078] In some example embodiments, the further request 216 may include at least one of the following: an ID of the relay terminal device 130; information about a second communication channel (e.g., Uu relay RLC CH) for transmitting traffic between the DU 125 and the relay terminal device 130, including, for example, the QoS of the Uu relay RLC CH; a mapping between the second communication channel and a tunnel for transmitting traffic between the CU 110 and the DU 125, such as a DL mapping from F1-U to the Uu relay RLC CH; an index of the tunnel; or a TEID of the tunnel that terminates at the CU 110 (such as a UL F-TEID). For example, the DU 125 may store at least one of the mapping or TEID included in the request 216.

[0079] In this case, DU 125 does not have the UE context of remote terminal device 140, and DU 125 does not need to know which remote terminal device F1-U or DL ​​mapping is for. It should be understood that DU 125 regards the traffic as the traffic of relay terminal device 130 and does not need to know the remote terminal device 140.

[0080] The DU 125 determines 225 a configuration 231 for transmitting the service based on the request 216. For example, the DU 125 may determine a configuration 231 for the DU 125 to transmit the service based on the request 216. Then, the DU 125 sends 230 the configuration 231 to the CU 120. On the receiving side, the CU 120 receives 235 the configuration 231 from the DU 125.

[0081] In some example embodiments, DU 125 may allocate a TEID (or F-TEID) of a tunnel between CU 110 and DU 125 for transmitting traffic that terminates at DU 125 based on request 216. For example, configuration 231 may include the TEID of the tunnel that terminates at DU 125. In some example embodiments, DU 125 may generate a channel configuration of a second communication channel (e.g., Uu relay RLC CH) for transmitting traffic between DU 125 and relay terminal device 130 based on request 216. For example, the channel configuration may include a physical channel configuration of the second communication channel, and / or a radio link control (RLC) configuration and / or a media access control (MAC) configuration. Subsequently, configuration 231 may include a channel configuration of the second communication channel between DU 125 and relay terminal device 130. For example, DU 125 may establish or modify the second communication channel based on the information received in request 216, and generate a channel configuration of the second communication channel established / modified between DU 125 and relay terminal device 130.

[0082] For example, operation 236 or 237 may be performed. In some example embodiments, the service mapping between the first communication channel (e.g., PC5 relay RLC CH) between the relay terminal device 130 and the remote terminal device 140 and the second communication channel (e.g., Uu relay RLC CH) between the DU 125 of the second network device and the relay terminal device 130 may be configured by the CU 120. In this case, Figure 2 As shown, CU 120 may send (240) a configuration message 241 toward the relay terminal device 130 via DU 125 to configure the relay terminal device 130 for service mapping between a first communication channel between the relay terminal device 130 and the remote terminal device 140, and a second communication channel between the DU 125 of the second network device and the relay terminal device 130. Accordingly, the relay terminal device 130 may receive (245) a configuration message 241 from the CU 120 via DU 125.

[0083] Then, if Figure 2 As shown, CU 120 sends (250) a response 251 to CU 110, the response including information for CU 110 to send or receive services of remote terminal device 140 to or from relay terminal device 130 via DU 125. On the receiving side, CU 110 receives (255) the response 251 from CU 120.

[0084] In some example embodiments, the response 251 may include at least one of the following: an ID of a second communication channel (e.g., Uu relay RLC CH) for transmitting traffic between the relay terminal device 130 and the DU 125 of the second network device, an index of a tunnel (e.g., F1-U tunnel) for transmitting traffic between the CU 110 and the DU 125 of the second network device, or a TEID (or F-TEID) of the tunnel terminating at the DU 125, which is used to establish the F1-U tunnel for the remote terminal device 140. Then, for example, the CU 110 may configure its UP to use the new DL F1-U TEID (or F-TEID) for the F1-U of the remote terminal device 140.

[0085] Alternatively or additionally, service mapping between a first communication channel (e.g., PC5 relay RLC CH) between the relay terminal device 130 and the remote terminal device 140, and a second communication channel (e.g., Uu relay RLC CH) between the DU 125 of the second network device and the relay terminal device 130 may be configured by the CU 110. In this case, based on information about the second communication channel between the DU 125 and the relay terminal device 130 acquired from the response 251 from the CU 120, the CU 110 may configure bearer mapping in the relay terminal device 130. Figure 2 As shown, CU 110 may send (260) a configuration message 261 toward the relay terminal device 130 via DU 115, the configuration message 261 being used to configure the relay terminal device 130 for service mapping between a first communication channel between the relay terminal device 130 and the remote terminal device 140, and a second communication channel between DU 125 and the relay terminal device 130. Accordingly, the relay terminal device 130 may receive (265) the configuration message 261 from CU 110 via DU 115.

[0086] On this basis, an F1-U tunnel of the remote terminal equipment 140 is established between the CU 110 and the DU 125 , while the PC5 relay RLC CH configuration of the remote terminal equipment 140 is still generated by the DU 115 .

[0087] Then, DL data transmission or UL data transmission between the CU 110 and the remote terminal device 140 can be supported via the DU 125 and the relay terminal device 130. For example, the relay terminal device 130 can receive a service from the remote terminal device 140, and then send the service to the DU 125. In addition, the service can be forwarded to the CU 110 via the F1-U tunnel established between the CU 110 and the DU 125. As another example, the first CU 110 can send the service of the remote terminal device 140 to the DU 125 via the F1-U tunnel established between the CU 110 and the DU 125. In addition, the relay terminal device 130 can receive a service from the DU 125, and then send the service to the remote terminal device 140.

[0088] In some example embodiments, after the service of the remote terminal device 140 may be transmitted via the SCG of the relay terminal device 130, the CU 110 may initiate an XnAP process to modify / release the offloaded service of the remote terminal device 140. For example, the CU 110 may send an additional request to the CU 120 to modify or release at least one of the following: the configuration of the service or the configuration of the service, the first communication channel between the remote terminal device 140 and the relay terminal device 130 for transmitting the service, the second communication channel between the DU 125 of the second network device and the relay terminal device 130 for transmitting the service, or the tunnel between the CU 110 and the DU 125 of the second network device for transmitting the service. For example, CU 110 may send the following request to CU 120: modify the configuration (e.g., QoS) of the service, or modify the QoS of the first communication channel for transmitting the service between the remote terminal device 140 and the relay terminal device 130, or modify the QoS of the second communication channel for transmitting the service between the DU 125 of the second network device and the relay terminal device 130, or modify the QoS of the F1-U tunnel for transmitting the service between the CU 110 and the DU 125 of the second network device. As another example, CU 110 may send the following request to CU 120: release the configuration of the service, or release the first communication channel for transmitting the service between the remote terminal device 140 and the relay terminal device 130, or release the second communication channel for transmitting the service between the DU 125 of the second network device and the relay terminal device 130, or release the F1-U tunnel for transmitting the service between CU 110 and the DU 125 of the second network device.

[0089] Alternatively or additionally, after the service of the remote terminal device 140 can be transmitted via the SCG of the relay terminal device 130, the CU 120 can initiate an XnAP process to modify / release the offloaded service of the remote terminal device 140. For example, the CU 120 can send an additional request to the CU 110 to modify or release at least one of the following: the configuration of the service or the configuration of the service, the first communication channel between the remote terminal device 140 and the relay terminal device 130 for transmitting the service, the second communication channel between the DU 125 of the second network device and the relay terminal device 130 for transmitting the service, or the tunnel between the CU 110 and the DU 125 of the second network device for transmitting the service. For example, CU 120 may send the following request to CU 110: modify the configuration of the service (e.g., QoS), or the QoS of the first communication channel for transmitting the service between the remote terminal device 140 and the relay terminal device 130, or the QoS of the second communication channel for transmitting the service between the DU 125 of the second network device and the relay terminal device 130, or the QoS of the F1-U tunnel for transmitting the service between the CU 110 and the DU 125 of the second network device. As another example, CU 120 may send the following request to CU 110: release the configuration of the service, or release the first communication channel for transmitting the service between the remote terminal device 140 and the relay terminal device 130, or release the second communication channel for transmitting the service between the DU 125 of the second network device and the relay terminal device 130, or release the F1-U tunnel for transmitting the service between the CU 110 and the DU 125 of the second network device.

[0090] In this way, by transmitting the services of the terminal device via the DU 125 and the relay terminal device, the mobility robustness and overall reliability of the network can be improved, especially when the communication channel between the CU 110 and the relay terminal device 130 is congested. Therefore, the switching interruption time can be reduced, and the communication efficiency and user experience can be improved.

[0091] In addition, it is allowed to maintain the current principle, that is, the MN as the first network device 103 configures the PC5 relay RLC CH for the relay terminal device 130 and the remote terminal device 140, while enabling the use of the SCG path of the relay terminal device 130 in the MR-DC to relay the service of the remote terminal device 140. It does not affect the remote terminal device 140, that is, the remote terminal device 140 does not know that the SCG path of the relay terminal device 130 is used.

[0092] Figure 3 An example process 300 is illustrated according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1AThe process 300 is described. The remote terminal device 140 is implemented by a remote UE 301. The relay terminal device 130 is implemented by a relay UE 303. The DU 105 is represented as MN-DU 305. The CU 110 includes a CP 307 and an UP 309, which are represented as MN-CU-CP 307 and MN-CU-UP 309, respectively. The DU 125 is represented as SN-DU 311. The CU 120 includes a CP 313, which is also represented as SN-CU-CP 313. The process 300 also involves a CN 315. It should be understood that although the CN 315 is described in detail in the present invention, the CN 315 is not described in detail in the present invention. Figure 1A The process 300 is described in the network environment 100, but the process 300 can also be applied to other communication scenarios.

[0093] like Figure 3 As shown, at 320-362, the conventional initial access procedure of the remote UE 301 is performed. The relay UE 303 always uses the MN for the remote UE 301. In this case, the sidelink UE information (SidelinkUEInformation) is sent to the MN-DU 305 and is further forwarded to the MN-CU-CP 307.

[0094] At 364, the MN-CU-CP 307 configures a PC5 relay RLC CH for the relay UE 303, which will be used for the SRB / DRB of the relay U2N remote UE 301. At 366, the MN-CU-CP 307 configures a PC5 relay RLC CH for the remote UE 301, which will be used for the SRB / DRB of the remote UE 301. The MN-DU 305 generates a PC5 relay RLC CH configuration for the remote UE 301 and the relay UE 303.

[0095] At 368, MN-CU-CP 307 decides to use the SCG of relay UE 303 to transmit the traffic of remote UE 301. This decision can be made based on various reasons, for example, Uu relay RLC CH congestion between MN-DU 305 and relay UE 303. MN-CU-CP 307 sends an XnAP REQUEST message to SN-CU-CP 313 to request to offload the traffic of remote UE 301 to the SCG path of relay UE 303. In other words, the XnAP request message requests to use SN-DU 311 and relay UE 303 to transmit traffic between remote UE 301 and MN-CU-UP 309.

[0096] For example, the XnAP request message may include information of the service to be offloaded to the SCG path, such as a list of information of the DRB / SRB of the remote UE 301, including: the ID of the relay UE 303, SRAP header information (such as the local ID of the remote UE, DRB ID, SRB ID, PC5 relay RLC CH ID) and the QoS of the DRB / PC5 relay RLC CH, which will be used by the SN-CU-CP 313 to configure the relay UE 303 for, for example, the mapping between the Uu relay RLC CH and the PC5 relay RL CH, and to configure the SN-DU for, for example, the mapping between the F1-U of the remote UE and the Uu relay RLC CH. Alternatively or additionally, the XnAP request message may include information of the Uu relay RLC CH required for offloading the service to the SCG path between the relay UE 303 and the SN-DU 311, such as the ID of the Uu relay RLC CH and the QoS of the Uu relay RLC CH. In this case, the PC5 relay RLC CH is still configured by the MN. The MN only sends the configured PC5 relay RLC CH ID and associated QoS to the SN so that the SN configures Uu-PC5 mapping in the relay UE 303 .

[0097] In addition, the XnAP request message may also include an F1-U tunnel index and a QoS associated with the F1-U tunnel, which will be used by the SN-CU-CP 313 to determine the required Uu relay RLCCH to be established or modified between the SN-DU 311 and the relay UE 303. The XnAP request message may also include a UL F-TEID terminated at the MN-CU-UP 309, which will be used by the SN-CU-CP 313 to configure the SN-DU 311 for forwarding UL UP traffic of the remote UE 301.

[0098] At 370, the SN-CU-CP 313 determines the required Uu relay RLC CH to be established / modified, and then sends a F1AP message to configure the SN-DU 311 for the traffic of the offloaded remote UE 301. The F1AP message may include an ID of the relay UE 303, for example, a gNB-CU UE F1AP ID if UE-associated signaling is used for the relay UE 303. The F1AP message may also include information about the Uu relay RLC CH to be established / modified for the traffic of the remote UE 301 for relay offloading, including the QoS of the Uu relay RLC CH. The F1AP message may also include information for DL ​​mapping, for example, DL mapping from the DL F1-U of the remote UE 301 to the Uu relay RLC CH. Alternatively or additionally, the F1AP message may also include F1-U tunnel information, for example, a UL F-TEID terminated at the MN-CU-UP 309.

[0099] Then, the SN-DU 311 performs the relevant configuration. For example, the SN-DU 311 may establish / modify the Uu relay RLC CH. The SN-DU 311 may save the DL mapping information and the F1-U tunnel information. The SN-DU 311 may allocate the DL F1-U tunnel information. The SN-DU 311 may generate the Uu relay RLC CH configuration for the relay UE 303. At 372, the SN-DU 311 replies to the SN-CU-CP 313 with the Uu relay RLCCH information and the DL F1-U tunnel information.

[0100] At 374, the SN-CU-CP 313 sends an F1AP message including an RRC reconfiguration (RRCReconfiguration) of the relay UE 303 to the SN-DU 311. At 376, the SN-DU 311 sends an RRC reconfiguration to the relay UE 303 to configure the Uu relay RLC CH and bearer mapping in the relay UE 303. Alternatively or additionally, the service mapping between the communication channel (e.g., Uu relay RLC CH) between the SN-DU 311 of the second network device and the relay UE 303 and the communication channel (e.g., PC5 relay RLC CH) between the relay UE 303 and the remote UE 301 can be configured by the MN-CU-CP 307.

[0101] At 378, the SN-CU-CP 313 sends an XnAP response message including information of the offloaded remote UE 301's traffic to the MN-CU-CP 307. For each DRB of the remote UE 301, the information may include a list of the following information of the F1-U tunnel of each remote UE 301: the F1-U tunnel index and the DL F-TEID terminated at the SN-DU 311, which will be forwarded by the MN-CU-CP 307 to configure the MN-CU-UP 309 for sending the UP traffic of the DL remote UE 301. In another example embodiment, the MN-CU-CP 307 may initiate an F1AP message including an RRC reconfiguration of the relay UE 303 toward the MN-DU 305. Then, the MN-DU 305 may send an RRC reconfiguration to the relay UE 303 to configure the Uu relay RLC CH and bearer mapping in the relay UE 303.

[0102] At 380 , the MN-CU-CP 307 sends the DL F-TEID terminated at the SN-DU 311 to the MN-CU-UP 309 so that the MN-CU-UP 309 can send the DL F1-U traffic of the remote UE 301 using the DL F-TEID.

[0103] On this basis, an F1-U tunnel for the remote UE 301 is established between the MN-CU-UP 309 and the SN-DU 311. In other words, the F1-U of the remote UE 301 is terminated at the MN-CU-UP 309 and the SN-DU 311, while the PC5 of the remote UE 301 is still configured by the MN. The communication path of the service of the remote UE 301 is shown at 382-398. The DL service of the remote UE 301 is sent via CN315->MN-CU-UP 309->SN-DU 311->relay UE 303->remote UE 301, as shown at 382-388. The UL service of the remote UE 301 is sent via the remote UE 301->relay UE 303->SN-DU 311->MN-CU-UP 309->CN 315, as shown at 390-398.

[0104] As mentioned above Figure 2 All operations and features described are also applicable to process 300 and have similar effects. For simplicity, details will be omitted.

[0105] Figure 4 A flowchart 400 of a method implemented at a central unit of a first network device according to some embodiments of the present disclosure is illustrated. For discussion purposes, reference will be made to Figure 1A The method 400 is described from the perspective of the central unit 110 .

[0106] At block 410, the central unit 110 sends a request to the central unit 120 of the second network device 105 to transmit a service between the remote terminal device and the central unit 110 using the distributed unit 125 of the second network device 105 and the relay terminal device, and the first network device 103 and the second network device 105 are the primary node and the secondary node of the relay terminal device. At block 420, the central unit 110 receives a response from the central unit 120, the response including information for the central unit 110 to send the service of the remote terminal device to the relay terminal device via the distributed unit 125 or to receive the service of the remote terminal device from the relay terminal device.

[0107] In some example embodiments, the central unit 110 also determines to request the use of the distributed unit 125 and the relay terminal device to transmit traffic between the central unit 110 and the remote terminal device based on determining that the communication channel between the distributed unit 115 of the first network device 103 and the relay terminal device is congested.

[0108] In some example embodiments, the request includes at least one of: an identifier of the relay terminal device; an identifier of the remote terminal device; an identifier of a data radio bearer for the service; an identifier of a signaling radio bearer for the service; a quality of service associated with the service; an identifier of a first communication channel between the remote terminal device and the relay terminal device for transmitting the service; the quality of service associated with the first communication channel; an index or identifier of a second communication channel required for transmitting the service between the distributed unit 125 of the second network device 105 and the relay terminal device; the quality of service associated with the second communication channel; an index of a tunnel between the central unit 110 and the distributed unit 125 of the second network device 105 for transmitting the service; the quality of service associated with the tunnel; or a tunnel endpoint identifier of the tunnel terminating at the central unit 110.

[0109] In some example embodiments, the response includes at least one of: an identifier of a second communication channel for transmitting services between the relay terminal device and the distributed unit 125 of the second network device 105; an index of a tunnel for transmitting services between the central unit 110 and the distributed unit 125 of the second network device 105; or a tunnel endpoint identifier of the tunnel terminating at the distributed unit 125.

[0110] In some example embodiments, the central unit 110 also sends an additional request to the central unit 120 to modify or release at least one of: the configuration of the service or the configuration of the service; a first communication channel for transmitting the service between the remote terminal device and the relay terminal device; a second communication channel for transmitting the service between the distributed unit 125 of the second network device 105 and the relay terminal device; or a tunnel for transmitting the service between the central unit 110 and the distributed unit 125 of the second network device 105.

[0111] In some example embodiments, the central unit 110 also receives an additional request from the central unit 120 to modify or release at least one of: the configuration of the service or the configuration of the service; a first communication channel between the remote terminal device and the relay terminal device for transmitting the service; a second communication channel between the distributed unit 125 of the second network device 105 and the relay terminal device for transmitting the service; or a tunnel between the central unit 110 and the distributed unit 125 of the second network device 105 for transmitting the service.

[0112] In some example embodiments, the central unit 110 also sends a configuration message toward the relay terminal device, which is used to configure the relay terminal device for mapping services between: a first communication channel between the relay terminal device and the remote terminal device and a second communication channel between the distributed unit 125 of the second network device 105 and the relay terminal device.

[0113] Figure 5 A flowchart 500 of a method implemented at the central unit 120 of the second network device 105 according to some embodiments of the present disclosure is illustrated. For discussion purposes, reference will be made to Figure 1A The method 500 is described from the perspective of the central unit 120 .

[0114] At block 510, the central unit 120 receives a request for transmitting a service between a remote terminal device and the central unit 110 using the distributed unit 125 of the second network device 105 and the relay terminal device from the central unit 110 of the first network device 103, the first network device 103 and the second network device 105 being the primary node and the secondary node of the relay terminal device. At block 520, the central unit 120 sends a response to the central unit 110, the response including information for the central unit 110 to send the service of the remote terminal device to the relay terminal device via the distributed unit 125 or to receive the service of the remote terminal device from the relay terminal device.

[0115] In some example embodiments, the request includes at least one of: an identifier of the relay terminal device; an identifier of the remote terminal device; an identifier of a data radio bearer for the service; an identifier of a signaling radio bearer for the service; a quality of service associated with the service; an identifier of a first communication channel between the remote terminal device and the relay terminal device for transmitting the service; the quality of service associated with the first communication channel; an index or identifier of a second communication channel required for transmitting the service between the distributed unit 125 of the second network device 105 and the relay terminal device; the quality of service associated with the second communication channel; an index of a tunnel between the central unit 110 and the distributed unit 125 of the second network device 105 for transmitting the service; the quality of service associated with the tunnel; or a tunnel endpoint identifier of the tunnel terminating at the central unit 110.

[0116] In some example embodiments, the response includes at least one of: an identifier of a second communication channel for transmitting services between the relay terminal device and the distributed unit 125 of the second network device 105; an index of a tunnel for transmitting services between the central unit 110 and the distributed unit 125 of the second network device 105; or a tunnel endpoint identifier of the tunnel terminating at the distributed unit 125.

[0117] In some example embodiments, the central unit 120 further sends to the distributed unit 125 an additional request to transmit traffic of the remote terminal device between the central unit 110 and the remote terminal device using the relay terminal device; and receives from the distributed unit 125 a configuration for transmitting traffic.

[0118] In some example embodiments, the additional request includes at least one of: an identifier of the relay terminal device; information about a second communication channel for transmitting services between the distributed unit 125 and the relay terminal device; a mapping between the second communication channel and a tunnel for transmitting services between the central unit 110 and the distributed unit 125; an index of the tunnel; or a tunnel endpoint identifier of the tunnel terminating at the central unit 110.

[0119] In some example embodiments, the configuration includes at least one of: a channel configuration of a second communication channel between the distributed unit 125 and the relay terminal device for transmitting services; or a tunnel endpoint identifier of a tunnel between the central unit 110 and the distributed unit 125 for transmitting services, terminating at the distributed unit 125.

[0120] In some example embodiments, the central unit 120 also receives from the central unit 110 an additional request to modify or release at least one of: configuration of the service; a first communication channel between the remote terminal device and the relay terminal device for transmitting the service; a second communication channel between the distributed unit 125 of the second network device 105 and the relay terminal device for transmitting the service; or a tunnel between the central unit 110 and the distributed unit 125 of the second network device 105 for transmitting the service.

[0121] In some example embodiments, the central unit 120 also sends an additional request to the central unit 110 to modify or release at least one of: the configuration of the service or the configuration of the service; a first communication channel for transmitting the service between the remote terminal device and the relay terminal device; a second communication channel for transmitting the service between the distributed unit 125 of the second network device 105 and the relay terminal device; or a tunnel for transmitting the service between the central unit 110 and the distributed unit 125 of the second network device 105.

[0122] In some example embodiments, the central unit 120 also sends a configuration message toward the relay terminal device, which is used to configure the relay terminal device for mapping services between: a first communication channel between the relay terminal device and the remote terminal device; and a second communication channel between the distributed unit 125 of the second network device 105 and the relay terminal device.

[0123] Figure 6 A flowchart 600 of a method implemented at a distributed unit 125 of a second network device 105 according to some embodiments of the present disclosure is illustrated. For discussion purposes, reference will be made to Figure 1A The method 600 is described from the perspective of the distributed unit 125 .

[0124] At block 610, the distributed unit 125 receives a request from the central unit 120 of the second network device 105 for the relay terminal device 130 to configure the distributed unit 125 to use the relay terminal device to transmit the service of the remote terminal device between the remote terminal device and the central unit 110 of the first network device 103, the first network device 103 and the second network device 105 being the primary node and the secondary node of the relay terminal device. At block 620, the distributed unit 125 determines the configuration for transmitting the service based on the request. At block 630, the distributed unit 125 sends the configuration to the central unit 120.

[0125] In some example embodiments, the request includes at least one of: an identifier of the relay terminal device; information about a second communication channel for transmitting services between the distributed unit 125 and the relay terminal device; a mapping between the second communication channel and a tunnel for transmitting services between the central unit 110 and the distributed unit 125; an index of the tunnel; or a tunnel endpoint identifier of the tunnel terminating at the central unit 110.

[0126] In some example embodiments, distributed unit 125 also stores at least one of a mapping or a tunnel endpoint identifier.

[0127] In some example embodiments, distributed unit 125 also allocates a tunnel endpoint identifier of a tunnel between central unit 110 and distributed unit 125 for transmitting traffic, which tunnel terminates at distributed unit 125, based on the request.

[0128] In some example embodiments, the distributed unit 125 also generates, based on the request, a channel configuration of a second communication channel between the distributed unit 125 and the relay terminal device for transmitting traffic.

[0129] In some example embodiments, the distributed unit 125 also establishes or modifies a second communication channel based on the request.

[0130] In some example embodiments, the configuration for transmitting the service includes at least one of the following: a channel configuration of a second communication channel between the distributed unit 125 and the relay terminal device for transmitting the service; or a tunnel endpoint identifier of a tunnel between the central unit 110 and the distributed unit 125 for transmitting the service, which terminates at the distributed unit 125.

[0131] In some example embodiments, the distributed unit 125 also transmits the traffic of the remote terminal device to the relay terminal device or receives the traffic of the remote terminal device from the relay terminal device.

[0132] Figure 7 700 of a method implemented at a relay terminal device according to some embodiments of the present disclosure is illustrated. For discussion purposes, reference will be made to Figure 1A The method 700 is described from the perspective of the relay terminal device 130 .

[0133] At box 710, the relay terminal device receives a configuration message from the central unit 110 of the first network device 103 or the central unit 120 of the second network device 105, which is used to configure the relay terminal device 130 for mapping the service of the remote terminal device 140 to be relayed by the relay terminal device 130 between: a first communication channel between the relay terminal device and the remote terminal device; and a second communication channel between the distributed unit 125 of the second network device 105 and the relay terminal device, wherein the first network device 103 and the second network device 105 are the main node and the auxiliary node of the relay terminal device.

[0134] In some example embodiments, the relay terminal device also receives services from a remote terminal device or a distributed unit 125; based on determining that the services come from a remote terminal device, sends services to the distributed unit 125 based on a configuration message; and based on determining that the services come from the distributed unit 125, sends services to the remote terminal device based on the configuration message.

[0135] In some example embodiments, a device capable of executing method 400 (e.g., central unit 110) may include components for executing the corresponding steps of method 400. The components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module.

[0136] In some example embodiments, the apparatus includes a component for sending a request to a central unit of a second network device to transmit services between a remote terminal device and a central unit of a first network device using a distributed unit of the second network device and a relay terminal device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and a component for receiving a response from the central unit of the second network device, the response including information for the central unit of the first network device to send services of the remote terminal device to the relay terminal device or to receive services of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0137] In some example embodiments, the apparatus further comprises a component for determining, based on determining that a communication channel between the distributed unit of the first network device and the relay terminal device is congested, to request the use of the distributed unit and the relay terminal device of the second network device to transmit services between the central unit of the first network device and the remote terminal device.

[0138] In some example embodiments, the request includes at least one of: an identifier of a relay terminal device; an identifier of a remote terminal device; an identifier of a data radio bearer for the service; an identifier of a signaling radio bearer for the service; a quality of service associated with the service; an identifier of a first communication channel between the remote terminal device and the relay terminal device for transmitting the service; the quality of service associated with the first communication channel; an index or identifier of a second communication channel required for transmitting the service between a distributed unit of a second network device and the relay terminal device; the quality of service associated with the second communication channel; an index of a tunnel for transmitting the service between a central unit of the first network device and a distributed unit of the second network device; the quality of service associated with the tunnel; or an identifier of a tunnel endpoint of the tunnel terminating at the central unit of the first network device.

[0139] In some example embodiments, the response includes at least one of: an identifier of a second communication channel for transmitting services between the relay terminal device and the distributed unit of the second network device; an index of a tunnel for transmitting services between the central unit of the first network device and the distributed unit of the second network device; or a tunnel endpoint identifier of the tunnel terminating at the distributed unit of the second network device.

[0140] In some example embodiments, the apparatus further comprises a component for sending to a central unit of a second network device an additional request to modify or release at least one of: a configuration of a service or a configuration of a service; a first communication channel between a remote terminal device and a relay terminal device for transmitting a service; a second communication channel between a distributed unit of the second network device and the relay terminal device for transmitting a service; or a tunnel between a central unit of the first network device and a distributed unit of the second network device for transmitting a service.

[0141] In some example embodiments, the apparatus further comprises a component for receiving from a central unit of a second network device an additional request to modify or release at least one of: a configuration of a service or a configuration of a service; a first communication channel between a remote terminal device and a relay terminal device for transmitting a service; a second communication channel between a distributed unit of the second network device and the relay terminal device for transmitting a service; or a tunnel between a central unit of the first network device and a distributed unit of the second network device for transmitting a service.

[0142] In some example embodiments, the apparatus further comprises a component for sending a configuration message toward a relay terminal device, the configuration message being used to configure the relay terminal device for mapping services between: a first communication channel between the relay terminal device and a remote terminal device; and a second communication channel between a distributed unit of a second network device and the relay terminal device.

[0143] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of method 400. In some embodiments, the means comprises at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to cause the above-mentioned execution of the apparatus together with the at least one processor.

[0144] In some example embodiments, a device capable of executing method 500 (e.g., central unit 120) may include components for executing the corresponding steps of method 500. The components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module.

[0145] In some example embodiments, the apparatus includes a component for receiving a request from a central unit of a first network device to transmit services between a remote terminal device and the central unit of the first network device using a distributed unit of a second network device and a relay terminal device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; and a component for sending a response to the central unit of the first network device, the response including information for the central unit of the first network device to send the services of the remote terminal device to the relay terminal device or to receive the services of the remote terminal device from the relay terminal device via the distributed unit of the second network device.

[0146] In some example embodiments, the request includes at least one of: an identifier of a relay terminal device; an identifier of a remote terminal device; an identifier of a data radio bearer for the service; an identifier of a signaling radio bearer for the service; a quality of service associated with the service; an identifier of a first communication channel between the remote terminal device and the relay terminal device for transmitting the service; the quality of service associated with the first communication channel; an index or identifier of a second communication channel required for transmitting the service between a distributed unit of a second network device and the relay terminal device; the quality of service associated with the second communication channel; an index of a tunnel for transmitting the service between a central unit of the first network device and a distributed unit of the second network device; the quality of service associated with the tunnel; or an identifier of a tunnel endpoint of the tunnel terminating at the central unit of the first network device.

[0147] In some example embodiments, the response includes at least one of: an identifier of a second communication channel for transmitting services between the relay terminal device and the distributed unit of the second network device; an index of a tunnel for transmitting services between the central unit of the first network device and the distributed unit of the second network device; or a tunnel endpoint identifier of the tunnel terminating at the distributed unit of the second network device.

[0148] In some example embodiments, the apparatus further comprises a component for sending to a distributed unit of a second network device an additional request for using a relay terminal device to transmit a service of a remote terminal device between a central unit of a first network device and the remote terminal device; and a component for receiving a configuration for transmitting the service from the distributed unit of the second network device.

[0149] In some example embodiments, the additional request includes at least one of: an identifier of the relay terminal device; information about a second communication channel for transmitting services between a distributed unit of the second network device and the relay terminal device; a mapping between the second communication channel and a tunnel for transmitting services between a central unit of the first network device and a distributed unit of the second network device; an index of the tunnel; or a tunnel endpoint identifier of the tunnel terminating at the central unit of the first network device.

[0150] In some example embodiments, the configuration includes at least one of the following: a channel configuration of a second communication channel for transmitting services between a distributed unit of a second network device and a relay terminal device; or a tunnel endpoint identifier of a tunnel for transmitting services between a central unit of a first network device and a distributed unit of a second network device, which terminates at the distributed unit of the second network device.

[0151] In some example embodiments, the apparatus further comprises a component for receiving from a central unit of a first network device an additional request to modify or release at least one of: a configuration of a service or a configuration of a service; a first communication channel between a remote terminal device and a relay terminal device for transmitting a service; a second communication channel between a distributed unit of a second network device and a relay terminal device for transmitting a service; or a tunnel between a central unit of the first network device and a distributed unit of a second network device for transmitting a service.

[0152] In some example embodiments, the apparatus further comprises a component for sending to a central unit of a first network device an additional request to modify or release at least one of: a configuration of a service or a configuration of a service; a first communication channel for transmitting a service between a remote terminal device and a relay terminal device; a second communication channel for transmitting a service between a distributed unit of a second network device and a relay terminal device; or a tunnel for transmitting a service between a central unit of the first network device and a distributed unit of a second network device.

[0153] In some example embodiments, the apparatus further comprises a component for sending a configuration message toward a relay terminal device, the configuration message being used to configure the relay terminal device for mapping services between: a first communication channel between the relay terminal device and a remote terminal device; and a second communication channel between a distributed unit of a second network device and the relay terminal device.

[0154] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of method 500. In some embodiments, the means comprises at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to cause the above-mentioned execution of the apparatus together with the at least one processor.

[0155] In some example embodiments, a device capable of performing method 600 (e.g., distributed unit 125) may include components for performing corresponding steps of method 600. The components may be implemented in any suitable form. For example, the components may be implemented in a circuit system or a software module.

[0156] In some example embodiments, the apparatus includes a component for receiving a request from a central unit of a second network device to use a relay terminal device to transmit a service of a remote terminal device between the remote terminal device and a central unit of a first network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; a component for determining a configuration for transmitting the service based on the request; and a component for sending the configuration to the central unit of the second network device.

[0157] In some example embodiments, the request includes at least one of: an identifier of the relay terminal device; information about a second communication channel for transmitting services between a distributed unit of the second network device and the relay terminal device; a mapping between the second communication channel and a tunnel for transmitting services between a central unit of the first network device and a distributed unit of the second network device; an index of the tunnel; or a tunnel endpoint identifier of the tunnel terminating at the central unit of the first network device.

[0158] In some example embodiments, the apparatus further comprises means for storing at least one of a mapping or a tunnel endpoint identifier.

[0159] In some example embodiments, the apparatus further comprises means for allocating, based on the request, a tunnel endpoint identifier of a tunnel between a central unit of the first network device and a distributed unit of the second network device for transmitting traffic, terminating at the distributed unit of the second network device.

[0160] In some example embodiments, the apparatus further comprises means for generating, based on the request, a channel configuration of a second communication channel for transmitting traffic between the distributed unit of the second network device and the relay terminal device.

[0161] In some example embodiments, the apparatus further comprises means for establishing or modifying a second communication channel based on the request.

[0162] In some example embodiments, the configuration for transmitting the service includes at least one of the following: a channel configuration of a second communication channel for transmitting the service between a distributed unit of a second network device and a relay terminal device; or a tunnel endpoint identifier of a tunnel for transmitting the service between a central unit of a first network device and a distributed unit of a second network device, which terminates at the distributed unit of the second network device.

[0163] In some example embodiments, the apparatus further comprises means for transmitting the traffic of the remote terminal device to the relay terminal device or receiving the traffic of the remote terminal device from the relay terminal device.

[0164] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of method 600. In some embodiments, the means comprises at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to cause the above-mentioned execution of the apparatus together with the at least one processor.

[0165] In some example embodiments, an apparatus capable of executing method 700 (e.g., relay terminal device 130) may include a component for executing the corresponding steps in method 700. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module.

[0166] In some example embodiments, the apparatus includes a component for receiving a configuration message from a central unit of a first network device or a central unit of a second network device, the configuration message being used to configure the relay terminal device for mapping services of a remote terminal device to be relayed by the relay terminal device between: a first communication channel between the relay terminal device and the remote terminal device; and a second communication channel between a distributed unit of the second network device and the relay terminal device, and wherein the first network device and the second network device are a primary node and a secondary node of the relay terminal device.

[0167] In some example embodiments, the apparatus further comprises a component for receiving a service from a remote terminal device or from a distributed unit of a second network device; a component for sending a service to a distributed unit of the second network device based on a configuration message based on determining that the service is from the remote terminal device; and a component for sending a service to a remote terminal device based on a configuration message based on determining that the service is from a distributed unit of the second network device.

[0168] In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of method 700. In some embodiments, the means comprises at least one processor; and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to cause the above-mentioned execution of the apparatus together with the at least one processor.

[0169] Figure 8 A simplified block diagram of a device 800 suitable for implementing some example embodiments of the present disclosure is illustrated. The device 800 may be provided to implement a communication device, such as Figure 1A The central unit 110, the central unit 120, the distributed unit 125 or the relay terminal device 130 are shown. As shown in the figure, the device 800 includes one or more processors 810, one or more memories 820 coupled to the processor 810, and one or more communication modules 840 coupled to the processor 810.

[0170] The communication module 840 is used for two-way communication. The communication module 840 has at least one antenna to facilitate communication. The communication interface may represent any interface required for communication with other network elements.

[0171] Processor 810 may be of any type suitable for the local technology network, and may include, as non-limiting examples, one or more of a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 800 may have multiple processors, such as application specific integrated circuit chips that are time slaved to a clock synchronized with a main processor.

[0172] The memory 820 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 824, electrically programmable read-only memory (EPROM), flash memory, hard disks, compact disks (CDs), digital video disks (DVDs), and other magnetic storage devices and / or optical storage devices. Examples of volatile memories include, but are not limited to, random access memory (RAM) 822 and other volatile memories that do not persist during power outages.

[0173] The computer program 830 includes computer executable instructions that are executed by the associated processor 810. The program 830 may be stored in the ROM 824. The processor 810 may perform any suitable actions and processes by loading the program 830 into the RAM 822.

[0174] The embodiments of the present disclosure may be implemented by a program 830, so that the device 800 may execute the reference Figures 2 to 3Any process of the present disclosure discussed. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0175] In some example embodiments, the program 830 may be tangibly embodied in a computer-readable medium that may be included in the device 800 (such as in the memory 820) or in other storage devices accessible to the device 800. The device 800 may load the program 830 from the computer-readable medium to the RAM 822 for execution. The computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc.

[0176] Fig. 9 830 is stored on the computer-readable medium 900. It should be noted that although the computer-readable medium 900 is stored on the computer-readable medium 900, the computer-readable medium 900 may be stored on the computer-readable medium 900. Fig. 9 Although depicted in the form of a CD or DVD, computer readable medium 900 may be in any other form suitable for carrying or storing program 830.

[0177] Generally, various embodiments of the present disclosure may be implemented using hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented using hardware, while other aspects may be implemented using firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are illustrated and described as block diagrams, flow charts, or using some other graphical representations, it should be understood that, as non-limiting examples, the blocks, devices, systems, techniques, or methods described herein may be implemented using hardware, software, firmware, dedicated circuits or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0178] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer executable instructions, such as instructions included in a program module, which are executed in a device on a target real or virtual processor to perform the above reference Figures 4 to 7 Any of the methods described in . Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various embodiments, the functions of program modules can be combined or split between program modules as needed. The machine executable instructions of program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in both local and remote storage media.

[0179] The program code for executing the method of the present disclosure can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device so that the program code is implemented when executed by the processor or controller in the flow chart and / or the block diagram. The program code can be executed completely on the machine, partially on the machine, as an independent software package, partially on the machine and partially on a remote machine, or completely on a remote machine or server.

[0180] In the context of the present disclosure, computer program codes or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of carriers include signals, computer readable media, etc.

[0181] Computer readable medium can be a computer readable signal medium or a computer readable storage medium. Computer readable medium can include but is not limited to electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. A more specific example of a computer readable storage medium will include an electrical connection with one or more wires, a portable computer floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term "non-transient" used herein is a restriction on the medium itself (i.e., tangible, rather than a signal), rather than a restriction on data storage persistence (e.g., RAM and ROM).

[0182] In addition, although the operations are described in a particular order, this should not be understood as requiring such operations to be performed in the particular order shown or in order or performing all the operations shown to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of the present disclosure, but rather descriptions of features that may be specific to a particular embodiment. Certain features described in the context of a separate embodiment may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination.

[0183] Although the disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features or acts described above are disclosed as example forms of implementing the claims.

Claims

1. A central unit of a first network device, comprising: at least one processor; as well as at least one memory storing instructions which, when executed by the at least one processor, cause the central unit of the first network device to at least: Sending a request to a central unit of a second network device to transmit a service between a remote terminal device and the central unit of the first network device using a distributed unit and a relay terminal device of the second network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; as well as A response is received from the central unit of the second network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device via the distributed unit of the second network device, or to receive the service of the remote terminal device from the relay terminal device.

2. The central unit of the first network device according to claim 1, wherein the central unit of the first network device is further configured to: Based on determining that the communication channel between the distributed unit of the first network device and the relay terminal device is congested, it is determined to request the use of the distributed unit and the relay terminal device of the second network device to transmit the service between the central unit of the first network device and the remote terminal device.

3. The central unit of the first network device according to claim 1 or 2, wherein the request comprises at least one of the following: An identifier of the relay terminal device; an identifier of the remote terminal device; an identifier of a data radio bearer used for the service; an identifier of a signalling radio bearer used for the service; the quality of service associated with the service; an identifier of a first communication channel between the remote terminal device and the relay terminal device for transmitting the service; a quality of service associated with said first communication channel; An index or identifier of a second communication channel required for transmitting the service between the distributed unit of the second network device and the relay terminal device; a quality of service associated with the second communication channel; an index of a tunnel between the central unit of the first network device and the distributed unit of the second network device for transmitting the service; a quality of service associated with the tunnel; or A tunnel endpoint identifier of the tunnel terminating at the central unit of the first network device.

4. The central unit of the first network device according to any one of claims 1 to 3, wherein the response comprises at least one of the following: an identifier of a second communication channel between the relay terminal device and the distributed unit of the second network device for transmitting the service; an index of a tunnel between the central unit of the first network device and the distributed unit of the second network device for transmitting the service; or A tunnel endpoint identifier of the tunnel terminating at the distributed unit of the second network device.

5. The central unit of the first network device according to any one of claims 1 to 4, wherein the central unit of the first network device is further configured to: Sending a further request to the central unit of the second network device to modify or release at least one of: Configuration of the service; A first communication channel between the remote terminal device and the relay terminal device for transmitting the service; a second communication channel between the distributed unit of the second network device and the relay terminal device for transmitting the service; or A tunnel between the central unit of the first network device and the distributed unit of the second network device is used to transmit the service.

6. The central unit of the first network device according to any one of claims 1 to 4, wherein the central unit of the first network device is further configured to: receiving, from the central unit of the second network device, a further request to modify or release at least one of: Configuration of the service; A first communication channel between the remote terminal device and the relay terminal device for transmitting the service; a second communication channel between the distributed unit of the second network device and the relay terminal device for transmitting the service; or A tunnel between the central unit of the first network device and the distributed unit of the second network device is used to transmit the service.

7. The central unit of the first network device according to any one of claims 1 to 6, wherein the central unit of the first network device is further configured to: Sending a configuration message towards the relay terminal device, the configuration message being used to configure the relay terminal device for mapping the service between the following items: a first communication channel between the relay terminal device and the remote terminal device; and A second communication channel between the distributed unit of the second network device and the relay terminal device.

8. A central unit of a second network device, comprising: at least one processor; as well as at least one memory storing instructions which, when executed by the at least one processor, cause the central unit of the second network device to at least: receiving, from a central unit of a first network device, a request to transmit a service between a remote terminal device and the central unit of the first network device using a distributed unit and a relay terminal device of the second network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; as well as A response is sent to the central unit of the first network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device via the distributed unit of the second network device, or to receive the service of the remote terminal device from the relay terminal device.

9. The central unit of the second network device according to claim 8, wherein the request comprises at least one of the following: An identifier of the relay terminal device; an identifier of the remote terminal device; an identifier of a data radio bearer used for the service; an identifier of a signalling radio bearer used for the service; the quality of service associated with the service; an identifier of a first communication channel between the remote terminal device and the relay terminal device for transmitting the service; a quality of service associated with said first communication channel; An index or identifier of a second communication channel required for transmitting the service between the distributed unit of the second network device and the relay terminal device; a quality of service associated with the second communication channel; an index of a tunnel between the central unit of the first network device and the distributed unit of the second network device for transmitting the service; a quality of service associated with the tunnel; or A tunnel endpoint identifier of the tunnel terminating at the central unit of the first network device.

10. The central unit of the second network device according to claim 8 or 9, wherein the response comprises at least one of the following: an identifier of a second communication channel between the relay terminal device and the distributed unit of the second network device for transmitting the service; an index of a tunnel between the central unit of the first network device and the distributed unit of the second network device for transmitting the service; or A tunnel endpoint identifier of the tunnel terminating at the distributed unit of the second network device.

11. The central unit of the second network device according to any one of claims 8 to 10, wherein the central unit of the second network device is further configured to: sending to the distributed unit of the second network device a further request to use the relay terminal device to transmit the service of the remote terminal device between the central unit of the first network device and the remote terminal device; and A configuration for transmitting the service is received from the distributed unit of the second network device.

12. The central unit of the second network device according to claim 11, wherein the further request comprises at least one of the following: An identifier of the relay terminal device; information about a second communication channel between the distributed unit of the second network device and the relay terminal device for transmitting the service; a mapping between the second communication channel and a tunnel for transmitting the traffic between the central unit of the first network device and the distributed unit of the second network device; an index of the tunnel; or A tunnel endpoint identifier of the tunnel terminating at the central unit of the first network device.

13. The central unit of the second network device according to claim 11 or 12, wherein the configuration comprises at least one of the following: channel configuration of a second communication channel between the distributed unit of the second network device and the relay terminal device for transmitting the service; or A tunnel endpoint identifier of a tunnel between the central unit of the first network device and the distributed unit of the second network device for transmitting the service, the tunnel terminating at the distributed unit of the second network device.

14. The central unit of the second network device according to any one of claims 8 to 13, wherein the central unit of the second network device is further configured to: receiving, from the central unit of the first network device, a further request to modify or release at least one of: Configuration of the service; A first communication channel between the remote terminal device and the relay terminal device for transmitting the service; a second communication channel between the distributed unit of the second network device and the relay terminal device for transmitting the service; or A tunnel between the central unit of the first network device and the distributed unit of the second network device is used to transmit the service.

15. The central unit of the second network device according to any one of claims 8 to 13, wherein the central unit of the second network device is further configured to: Sending a further request to the central unit of the first network device to modify or release at least one of: Configuration of the service; A first communication channel between the remote terminal device and the relay terminal device for transmitting the service; a second communication channel between the distributed unit of the second network device and the relay terminal device for transmitting the service; or A tunnel between the central unit of the first network device and the distributed unit of the second network device is used to transmit the service.

16. The central unit of the second network device according to any one of claims 8 to 15, wherein the central unit of the second network device is further configured to: Sending a configuration message towards the relay terminal device, the configuration message being used to configure the relay terminal device for mapping the service between the following items: a first communication channel between the relay terminal device and the remote terminal device; and A second communication channel between the distributed unit of the second network device and the relay terminal device.

17. A distributed unit of a second network device, comprising: at least one processor; as well as at least one memory storing instructions, which when executed by the at least one processor cause the distributed unit of the second network device to at least: receiving, from the central unit of the second network device, a request to use a relay terminal device to transmit a service of a remote terminal device between the remote terminal device and the central unit of the first network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; determining, based on the request, a configuration for delivering the service; as well as The configuration is sent to the central unit of the second network device.

18. The distributed unit of the second network device according to claim 17, wherein the request comprises at least one of the following: An identifier of the relay terminal device; information about a second communication channel between the distributed unit of the second network device and the relay terminal device for transmitting the service; a mapping between the second communication channel and a tunnel for transmitting the traffic between the central unit of the first network device and the distributed unit of the second network device; an index of the tunnel; or A tunnel endpoint identifier of the tunnel terminating at the central unit of the first network device.

19. The distributed unit of the second network device according to claim 18, wherein the distributed unit of the second network device is further configured to: At least one of the mapping or the tunnel endpoint identifier is stored.

20. The distributed unit of the second network device according to any one of claims 17 to 19, wherein the distributed unit of the second network device is further configured to: A tunnel endpoint identifier of a tunnel between the central unit of the first network device and the distributed unit of the second network device for transmitting the traffic, which tunnel terminates at the distributed unit of the second network device, is allocated based on the request.

21. The distributed unit of the second network device according to any one of claims 17 to 19, wherein the distributed unit of the second network device is further configured to: A channel configuration of a second communication channel for transmitting the service between the distributed unit of the second network device and the relay terminal device is generated based on the request.

22. The distributed unit of the second network device according to claim 21, wherein the distributed unit of the second network device is further configured to: The second communication channel is established or modified based on the request.

23. The distributed unit of the second network device according to any one of claims 21 or 22, wherein the configuration for transmitting the service comprises at least one of the following: the channel configuration of the second communication channel for transmitting the service between the distributed unit of the second network device and the relay terminal device; or A tunnel endpoint identifier of a tunnel between the central unit of the first network device and the distributed unit of the second network device for transmitting the service, the tunnel terminating at the distributed unit of the second network device.

24. The distributed unit of the second network device according to any one of claims 17 to 23, wherein the distributed unit of the second network device is further configured to perform at least one of the following: The service of the remote terminal device is sent to the relay terminal device, or the service of the remote terminal device is received from the relay terminal device.

25. A relay terminal device, comprising: at least one processor; as well as At least one memory stores instructions, which, when executed by the at least one processor, cause the relay terminal device to at least: A configuration message is received from a central unit of the first network device or a central unit of the second network device, wherein the configuration message is used to configure the relay terminal device for mapping of services of a remote terminal device to be relayed by the relay terminal device between the following items: a first communication channel between the relay terminal device and the remote terminal device; and a second communication channel between the distributed unit of the second network device and the relay terminal device, and The first network device and the second network device are the main node and the auxiliary node of the relay terminal device.

26. The relay terminal device according to claim 25, wherein the relay terminal device is further configured to: receiving the service from the remote terminal device or from the distributed unit of the second network device; Based on determining that the service is from the remote terminal device, sending the service to the distributed unit of the second network device based on the configuration message; and Based on determining that the service comes from the distributed unit of the second network device, the service is sent to the remote terminal device based on the configuration message.

27. A method comprising: At a central unit of a first network device, sending a request to a central unit of a second network device to transmit a service between a remote terminal device and the central unit of the first network device using a distributed unit and a relay terminal device of the second network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; as well as A response is received from the central unit of the second network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device via the distributed unit of the second network device, or to receive the service of the remote terminal device from the relay terminal device.

28. A method comprising: receiving, at a central unit of a second network device, from a central unit of a first network device, a request to transmit a service between a remote terminal device and the central unit of the first network device using a distributed unit and a relay terminal device of the second network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; as well as A response is sent to the central unit of the first network device, the response including information for the central unit of the first network device to send the service of the remote terminal device to the relay terminal device via the distributed unit of the second network device, or to receive the service of the remote terminal device from the relay terminal device.

29. A method comprising: receiving, at a distributed unit of a second network device, a request from a central unit of the second network device to use a relay terminal device to transmit a service of a remote terminal device between the remote terminal device and a central unit of a first network device, the first network device and the second network device being a primary node and a secondary node of the relay terminal device; determining, based on the request, a configuration for delivering the service; as well as The configuration is sent to the central unit of the second network device.

30. A method comprising: At the relay terminal device, a configuration message is received from a central unit of the first network device or a central unit of the second network device, wherein the configuration message is used to configure the relay terminal device for mapping of services of the remote terminal device to be relayed by the relay terminal device between the following items: a first communication channel between the relay terminal device and the remote terminal device; and a second communication channel between the distributed unit of the second network device and the relay terminal device, and The first network device and the second network device are the main node and the auxiliary node of the relay terminal device.

31. A non-transitory computer readable medium comprising program instructions for causing an apparatus to at least perform the method according to any one of claims 27 to 30.

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