Configuring wireless backhaul link for relaying wireless communication signals between nodes

Abstract

In an integrated access and backhaul (IAB) network, an IAB node may provide wireless access services and wireless backhaul services for user equipment. In such a network, one or more IAB nodes may act as relay nodes to relay data between the UE and the core network. Embodiments relate to configuring a wireless backhaul link for relaying wireless communication packets between an IAB relay node and a centralized network node. The centralized IAB node maps a user equipment (UE) bearer associated with the UE to at least one backhaul bearer, the UE bearer being between the UE and the network node, and the backhaul bearer being between the relay node and the network node. The centralized node then sends the mapping to the relay node.

Description

Technical Field

[0001] Various example embodiments are directed to configuring a wireless backhaul link for relaying packets between nodes in a wireless communication network, and in particular in a network supporting Integrated Access and Backhaul (IAB). Background Art

[0002] In an integrated access and backhaul (IAB) network, an IAB node can provide wireless access services and wireless backhaul services for user equipment. In such a network, one or more IAB nodes can act as relay nodes that relay data between the UE and the core network. The service data of the user equipment can be sent by the IAB node to another node, such as a base station, via a wireless backhaul link. The other node can be connected to the 5G core network element and can be referred to as an IAB donor node.

[0003] When the IAB node is a mobile node, the IAB donor node connected to another node is frequently changed, and this may have a high signaling overhead, especially if the IAB node has descendants and the topology changes.

[0004] Embodiments attempt to address these issues Summary of the invention

[0005] The scope of protection sought by various exemplary embodiments is set out by the independent claims. Exemplary embodiments and features described in this specification that do not fall within the scope of the independent claims, if any, should be construed as examples that aid in understanding the various embodiments of the invention.

[0006] According to various (but not necessarily all) example embodiments, according to one aspect, there is provided an apparatus for supporting wireless communications at a network node, the apparatus comprising: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, causes the apparatus or the network node to at least perform: mapping at least one user equipment UE bearer associated with a UE to at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the network node, and the at least one backhaul bearer is between a relay node and the network node; and sending a message to the relay node indicating the mapping of the at least one UE bearer to the at least one backhaul bearer.

[0007] Embodiments provide mapping of user plane bearers to backhaul bearers between relay nodes and network nodes. The backhaul bearers may be terminated at the network nodes. In this way, the backhaul connection does not require an intermediate protocol layer, so in the case where the relay node is mobile (such as in a vehicle), there is no need to change the topology as the cell to which the relay node is connected changes.

[0008] In some example embodiments, the relay node is at least partially controlled by the network node.

[0009] In some example embodiments, the portion includes a distributed unit portion of the relay node but does not include an MT mobile terminated portion.

[0010] In some example embodiments, the mapping comprises an association between the at least one UE bearer and the at least one backhaul bearer, and the message comprises a UE context modification request.

[0011] In some example embodiments, the at least one UE bearer is carried in an F1-U tunnel between the relay node and the network node.

[0012] In some example embodiments, the backhaul bearer is identified by an identifier and the F1-U tunnel is identified by an identifier, and the mapping includes information linking the identifiers.

[0013] In some example embodiments, the apparatus is caused to perform: in response to a first request to act as an auxiliary network node, acting as the auxiliary node.

[0014] In some example embodiments, the first request is generated in the apparatus itself in response to determining that the relay node comprises an IAB integrated access and backhaul node.

[0015] In some example embodiments, the apparatus is caused to perform, in response to receiving a request to terminate the at least one backhaul bearer, terminating the at least one backhaul bearer.

[0016] In some example embodiments, at least one of the first request and the request to terminate the at least one backhaul bearer is received from a further network node.

[0017] In some example embodiments, the request to terminate the backhaul bearer is received as part of the first request, in other embodiments it is received as a separate request, in which case it may be received before or after the "first" request.

[0018] In some example embodiments, the apparatus or network node is further caused to perform: generating a request requesting the further network node to establish or modify a configuration for a radio connection for the at least one backhaul bearer; and sending the request to the further network node.

[0019] In some example embodiments, the request to the further network node to establish or modify comprises assisting the node in modifying a required message.

[0020] In some example embodiments, the relay node comprises a mobile IAB node.

[0021] In some example embodiments, the mapping of the at least one UE bearer to the at least one backhaul bearer includes mapping the plurality of the UE bearers to one backhaul bearer among the backhaul bearers.

[0022] In some example embodiments, the apparatus includes a control plane entity and a user plane entity, the control plane entity being configured to perform: providing information associated with the mapping of the at least one UE bearer to the at least one backhaul bearer to the user plane entity, the user plane entity being configured to perform the mapping based on the information.

[0023] In some example embodiments, the device or network node is also caused to perform: receiving a response to the message indicating the mapping from the relay node, the response confirming that the message indicating the mapping is received at the relay node, and confirming that the mapping of the at least one UE bearer to the at least one backhaul bearer is performed at the relay node.

[0024] According to various but not necessarily all example embodiments, according to another aspect, there is provided an apparatus for supporting wireless communications at a relay network node for relaying packets between a user equipment and a network node, the apparatus comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, cause the apparatus or the relay network node to at least perform: receiving a message from a network node indicating a mapping between at least one UE bearer and at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the network node and the at least one backhaul bearer is between the relay node and the network node; and in response to receiving the message, performing the mapping of the at least one UE bearer to the at least one backhaul bearer based on the mapping between the at least one UE bearer and the at least one backhaul bearer.

[0025] In some example embodiments, the mapping comprises an association between the at least one UE bearer and the at least one backhaul bearer, and the message comprises a UE context modification request.

[0026] In some example embodiments, the at least one UE bearer is carried in an F1-U tunnel between the relay node and the network node, and the mapping of the at least one UE bearer to the at least one backhaul bearer includes mapping the at least one F1-U tunnel to the at least one backhaul bearer.

[0027] In some example embodiments, the apparatus or relay network node is caused to perform: sending a response to the message indicating the mapping, the response confirming that the mapping of the at least one UE bearer to the at least one backhaul bearer is performed at the relay node.

[0028] According to various but not necessarily all example embodiments, there is provided a wireless communication system comprising a relay network node supported by an apparatus according to another aspect, the relay network node being configured to receive packets from a user equipment and to relay packets received from the user equipment to a network node supported by an apparatus according to one aspect.

[0029] According to various but not necessarily all example embodiments, there is provided an apparatus for supporting wireless communications at another network node, the apparatus comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, cause the apparatus or the other network node to at least: receive a packet from a relay network node; determine whether the relay network node comprises an integrated access and backhaul relay node; and, if so: generate a request requesting the network node to act as an auxiliary network node; and send the request to the network node.

[0030] According to various but not necessarily all example embodiments, a method for supporting wireless communication at a network node is provided, the method comprising: mapping at least one user equipment (UE) bearer associated with a UE to at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the network node, and the at least one backhaul bearer is between a relay node and the network node; and sending a message to the relay node indicating the mapping of the at least one UE bearer to the at least one backhaul bearer.

[0031] In some example embodiments, the method further comprises, in response to a first request to serve as a secondary network node, serving as the secondary node.

[0032] In some example embodiments, the method further comprises: terminating the at least one backhaul bearer in response to receiving a request to terminate the at least one backhaul bearer.

[0033] In some example embodiments, the method further comprises receiving at least one of the first request and the request to terminate the at least one backhaul bearer from a further network node.

[0034] In some example embodiments, the method further comprises generating a request requesting the further network node to establish or modify a configuration for a radio connection for the at least one backhaul bearer; and sending the request to the further network node.

[0035] In some example embodiments, the step of mapping the at least one UE bearer to the at least one backhaul bearer includes mapping a plurality of the UE bearers to one backhaul bearer among the backhaul bearers.

[0036] In some example embodiments, the method further includes receiving a response from the relay node to the message indicating the mapping, the response confirming receipt of the message indicating the mapping at the relay node and confirming performance of the mapping of the at least one UE bearer to the at least one backhaul bearer at the relay node.

[0037] According to various but not necessarily all example embodiments, there is provided a method for supporting wireless communication at a relay network node for relaying packets between a user equipment and the network node, the method comprising:

[0038] Receiving a message from a network node indicating a mapping between at least one UE bearer and at least one backhaul bearer, wherein the at least one UE bearer is between a UE and the network node, and the at least one backhaul bearer is between the relay node and the network node; and in response to receiving the message, mapping the at least one UE bearer to the at least one backhaul bearer based on the mapping between the at least one UE bearer and the at least one backhaul bearer.

[0039] In some example embodiments, the at least one UE bearer is carried in an F1-U tunnel between the relay node and the network node, and the step of mapping the at least one UE bearer to the at least one backhaul bearer includes mapping the at least one F1-U tunnel to the at least one backhaul bearer.

[0040] In some example embodiments, the method further comprises sending a response to the message indicating the mapping, the response confirming that the mapping of the at least one UE bearer to the at least one backhaul bearer is performed at the relay node.

[0041] According to various but not necessarily all example embodiments, a method for supporting wireless communications at another network node is provided, the method comprising: receiving a packet from a relay network node; determining whether the relay network node comprises an integrated access and backhaul relay node; and if so: generating a request requesting the network node to act as an auxiliary network node; and sending the request to the network node.

[0042] According to various but not necessarily all example embodiments, there is provided a computer program comprising computer instructions which, when executed by at least one processor on a device, are configured to control the device to perform a method according to one or more of the method steps described above.

[0043] According to various but not necessarily all example embodiments, a non-transitory computer-readable medium is provided, including program instructions stored thereon, for performing at least the following at a network node: mapping at least one user equipment (UE) bearer associated with a UE to at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the network node, and the at least one backhaul bearer is between a relay node and the network node, generating a message for transmission of the mapping to a relay node, and controlling the network node to send the message to the relay node.

[0044] According to various but not necessarily all example embodiments, a non-transitory computer-readable medium is provided, including program instructions stored thereon, for performing at least the following at a relay node: mapping at least one UE bearer to at least one backhaul bearer based on a message received from a network node indicating a mapping of the at least one UE bearer and the at least one backhaul bearer.

[0045] According to various but not necessarily all example embodiments, there is provided an apparatus for supporting wireless communications at a network node, the apparatus comprising: a component for mapping at least one user equipment (UE) bearer associated with a UE to at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the network node, and the at least one backhaul bearer is between a relay node and the network node; and a component for controlling transmission of a message to the relay node indicating the mapping of the at least one UE bearer to the at least one backhaul bearer.

[0046] In some example embodiments, the control device is further configured to control the device to act as an auxiliary node in response to a first request to act as the auxiliary network node.

[0047] In some example embodiments, the control apparatus is further configured to control the apparatus to terminate the at least one backhaul bearer in response to receiving a request to terminate the at least one backhaul bearer.

[0048] In some example embodiments, at least one of the first request and the request to terminate the at least one backhaul bearer is received from a further network node.

[0049] In some example embodiments, the apparatus further comprises means for generating a request requesting the further network node to establish or modify a configuration of a radio connection for the at least one backhaul bearer; and means for controlling transmission of the request to the further network node.

[0050] In some example embodiments, the apparatus comprises a control plane entity and a user plane entity, the control plane entity comprising means for providing information associated with the mapping of the at least one UE bearer to the at least one backhaul bearer to the user plane entity, the user plane entity comprising the means for mapping, the mapping being performed based on the information.

[0051] In some example embodiments, the apparatus further comprises means for receiving a response from the relay node to the message indicating the mapping, the response confirming receipt of the message indicating the mapping at the relay node and confirming execution of the mapping of the at least one UE bearer to the at least one backhaul bearer at the relay node.

[0052] According to various but not necessarily all example embodiments, there is provided an apparatus for supporting wireless communications at a relay network node for relaying packets between a user equipment and a network node, the apparatus comprising: a component for receiving a message from a network node indicating a mapping between at least one UE bearer and at least one backhaul bearer, wherein the at least one UE bearer is between a UE and the network node, and the at least one backhaul bearer is between the relay node and the network node; and a component for performing, in response to receiving the message, mapping the at least one UE bearer to the at least one backhaul bearer based on the mapping between the at least one UE bearer and the at least one backhaul bearer.

[0053] In some example embodiments, the apparatus further comprises means for controlling transmission of a response to the message indicating the mapping, the response confirming that the mapping of the at least one UE bearer to the at least one backhaul bearer is performed at the relay node.

[0054] According to various but not necessarily all example embodiments, there is provided an apparatus for supporting wireless communications at an additional network node, the apparatus comprising: a component for receiving a packet from a relay network node; a component for determining whether the relay network node comprises an integrated access and backhaul relay node; a component for generating a request to request a network node to act as an auxiliary network node; and a component for controlling transmission of the request to the network node.

[0055] According to various but not necessarily all example embodiments, there is provided an apparatus for supporting wireless communications at a network node, the apparatus comprising: a mapping circuit system configured to map at least one user equipment (UE) bearer associated with a UE to at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the network node, and the at least one backhaul bearer is between a relay node and the network node; and a control circuit system configured to control transmission of a message to the relay node indicating the mapping of the at least one UE bearer to the at least one backhaul bearer.

[0056] In some example embodiments, the control circuitry is further configured to control the apparatus to act as an auxiliary node in response to a first request to act as the auxiliary network node.

[0057] In some example embodiments, the control circuitry is further configured to control the apparatus to terminate the at least one backhaul bearer in response to receiving a request to terminate the at least one backhaul bearer.

[0058] In some example embodiments, at least one of the first request and the request to terminate the at least one backhaul bearer is received from a further network node.

[0059] In some example embodiments, the control circuitry is further configured to control the apparatus to generate a request requesting the further network node to establish or modify a configuration of a radio connection for a backhaul bearer; and to send the request to the further network node.

[0060] In some example embodiments, the apparatus includes a control plane entity and a user plane entity, the control plane entity including a circuit system configured to provide information associated with the mapping of the at least one UE bearer to the at least one backhaul bearer to the user plane entity, the user plane entity including the mapping circuit system, the mapping circuit system configured to perform the mapping based on the information.

[0061] In some example embodiments, the apparatus further comprises a circuit system for receiving a response to the message indicating the mapping from the relay node, the response confirming receipt of the message indicating the mapping at the relay node and confirming performance of the mapping of the at least one UE bearer to the at least one backhaul bearer at the relay node.

[0062] According to various but not necessarily all example embodiments, there is provided an apparatus for supporting wireless communications at a relay network node, for relaying packets between a user equipment and a network node, the apparatus comprising: a circuit system configured to receive a message from the network node indicating a mapping between at least one UE bearer and at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the network node, and the at least one backhaul bearer is between the relay node and the network node; and a mapping circuit system configured to, in response to receiving the message, map the at least one UE bearer to the at least one backhaul bearer based on the mapping between the at least one UE bearer and the at least one backhaul bearer.

[0063] In some example embodiments, the apparatus further comprises circuitry configured to control transmission of a response to the message indicating the mapping, the response confirming that the mapping of the at least one UE bearer to the at least one backhaul bearer is performed at the relay node.

[0064] According to various but not necessarily all example embodiments, there is provided an apparatus for supporting wireless communications at an additional network node, the apparatus comprising: a circuit system configured to receive a packet from a relay network node; a circuit system configured to determine whether the relay network node comprises an integrated access and backhaul relay node; a circuit system configured to generate a request for the requesting network node to act as an auxiliary network node; and a circuit system configured to control transmission of the request to the network node.

[0065] Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

[0066] When a device feature is described as being usable to provide a function, it should be understood that this includes device features that provide that function or are adapted or configured to provide that function. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0068] Figure 1 The basic structure of the IAB network architecture is shown;

[0069] Figure 2 shows the structure of a radio access network supporting a single-hop backhaul for a mobile IAB node according to an embodiment;

[0070] Figure 3 shows the division between protocol stacks and nodes according to an embodiment;

[0071] Figure 4 Schematically illustrates the signaling between nodes during the mobile IAB node integration process;

[0072] Figure 5 shows the signaling between nodes during establishment of a UE connection and how data bearers are configured when accessed via a mobile IAB node;

[0073] Figure 6 schematically illustrates examples of possible modifications to messages to support UE bearer configuration via a mobile IAB node; and

[0074] Figure 7 Nodes in a network according to an embodiment are schematically illustrated. DETAILED DESCRIPTION

[0075] Before discussing example embodiments in greater detail, an overview will first be provided.

[0076] In an integrated access and backhaul (IAB) network, an IAB node may provide wireless access services and wireless backhaul services for control and data transmission. One or more IAB nodes may act as relay nodes that relay data between the UE and the core network. An IAB network may have two types of IAB nodes, an IAB donor node is a base station with a wired backhaul to the 5G core network, and an IAB node or relay node uses one or more wireless backhaul links to reach the IAB donor node. Therefore, the IAB donor node acts as a radio access gateway for the relay node.

[0077] In the case where the IAB node is a mobile node, the IAB donor node connected to the IAB node may change frequently, which may have a high signaling overhead, especially in the case where the IAB node has descendants and the topology changes.

[0078] Embodiments seek to address these issues by using data bearers (DRBs) to carry backhaul data and mapping user equipment (UE) data bearers to backhaul data bearers used for wireless backhaul links from IAB nodes to nodes in the network. By doing so, the IAB backhaul connection does not require an intermediate protocol layer, so in the case where the IAB is mobile (such as on a vehicle) and changes frequently, when the donor node to which the IAB node is connected changes, there is no need to change the topology. Multiple UEs can use a single backhaul link using aggregation controlled in SDAP (Service Data Adaptation Protocol) or a corresponding layer.

[0079] The relay IAB node appears to the donor node as a UE. In an embodiment, the donor node may determine that the IAB relay node is not a UE but an IAB relay based on an indication of the device type during the IAB node access process or receiving such information from the core network. With the connection device type (i.e., the IAB node) known, the IAB donor may initiate an auxiliary node addition process and send an auxiliary node addition request message to another node. The other node may be preconfigured to select a specific node as a node that later becomes a termination node for both backhaul and UE data bearer and a distributed unit (DU) portion of the control IAB node. The other node is an anchor node or a centralized node and acts as an auxiliary node toward the donor network node for the backhaul connection, but acts as a master node for the core network toward the QoS flow to be mapped for the UE bearer.

[0080] Figure 1 An IAB network architecture is shown, where a UE 10 is connected to distributed units 22 of IAB nodes 20. These IAB nodes act as relay nodes for relaying packets between the UE and an IAB donor 30, which may be a base station and provides wired access to the core network CN.

[0081] In this example, layer 2 L2 relay is used and a new protocol layer (BAP, Backhaul Adaptation Protocol) is introduced for routing and channel mapping. One of the main arguments for L2 relay is that it can be hidden from the core network (CN) and there is no CN interface through the radio interface. This also means that the centralized unit CU (donor) should be located at a fixed site with a wired connection to the CN. This gives rise to an IAB architecture with a split gNB structure, where the DU function 22 is located in the IAB node 20.

[0082] In this architecture, the CN interface is terminated at the IAB donor, so the relay is only a RAN function. The solution leverages a split gNB architecture for Centralized Unit (CU) and Distributed Unit (DU) such that the CU functionality is at the IAB donor and the DU is at the IAB node. For connection setup and communication with the parent node (which can be another IAB node or an IAB donor), the IAB node hosts the MT (Mobile Terminal) functionality corresponding to the UE operations or a portion of the UE operations.

[0083] For single-hop mobile IAB scenarios, such IAB specifications result in excessive overhead on the BH backhaul link, unnecessary signaling and configuration of related nodes due to IAB node mobility, and unnecessary HO:s (handovers) for access UEs connected to mobile IAB nodes. For example, routing is not relevant to single-hop backhaul links, thus making routing configuration and related routing functions for donor DUs and IAB nodes obsolete. The term "single-hop" refers to a single backhaul link between a mobile IAB node and a fixed serving node, which can be a donor node or an intermediate IAB node.

[0084] Embodiments seek to address such issues, and the following RAN architecture is proposed for both mobile IAB and fixed IAB scenarios, including a centralized CU functionality dedicated to the control of mobile / fixed IAB nodes and the control (RRC) of UEs connected to the (multiple) cells of the mobile / fixed IAB nodes. Although the proposed architecture is applicable to both fixed and mobile IAB nodes, the mobile IAB node will be considered below as it is particularly advantageous in such scenarios. Figure 2 The structure is shown.

[0085] Figure 2 The structure of a radio access network supporting single-hop BH for mobile IAB according to one embodiment is shown.

[0086] This embodiment proposes the following specific features:

[0087] Centralized mobile-CU, m-CU can be the anchor node that controls the mobile IAB node (F1-C control plane) and the access UEs connected to the mobile IAB-node (RRC radio resource control)

[0088] • The donor provides service for the cell of the IAB Node BH link carrying the BH Data Radio Bearer (DRB).

[0089] Mobile IAB-MT is RRC connected to the serving (access network) node CU (donor-CU)

[0090] m-CU-UP Mobile Central Unit User Plane Termination DRB for BH and Access Links

[0091] UE DRBs can be aggregated at m-CU-UP (optional) for BH links

[0092] · Donor-CU and m-CU can communicate over Xn to configure GTP tunnel to carry BH DRBs between m-CU-UP and Donor-DU. Donor-CU configures Donor-DU for BH connection· Mobile IAB-node connects to fixed (stationary) node (donor) which can be partially IAB capable

[0093] CP control plane signaling (F1-C UE RRC) can be carried via Xn between donor-CU and m-CU, or via BH RRC between donor and IAB-MT - CP / UP split for NR (New Radio, also known as 5G Radio) Dual Connectivity (DC) as per Rer.17 IAB specification

[0094] The BH link does not require the BAP backhaul adaptation protocol layer; no routing is required on a single link, and the mapping (aggregation) of UE bearers to BH bearers can be done in the m-CU-UP

[0095] The logical structure of the mobile IAB is consistent with R16 / 17 IAB, the CU is in the fixed network, and the DU is at the IAB node. The MT mobile terminal establishes / maintains a connection with the service network for BH data.

[0096] The physical architecture for the network does not have to define the location of the m-CU, and it can be a normal base station or a virtual node in the RAN cloud. In addition, the IAB donor architecture can be cloud-based, where the CU is in the cloud. The advantage of a cloud-based architecture is the flexibility to serve large areas with dedicated mobile functions serving mobile IAB-nodes.

[0097] The UP protocol stack of the proposed solution is as follows Figure 3 As shown:

[0098] At the top, there are UE bearers (SDAP / PDCP) mapped to the F1-U user plane using traditional principles. The F1-U is transported in the DRB configured for the BH link. Multiple UE bearers (F1-U tunnels) can be aggregated to a single BH bearer in SDAP'. The SDAP' layer will be different from standard SDAP in that its mapping (aggregation to BH bearer) as input is the F1-U carrying the UE bearers, not the QoS flows from the core network.

[0099] Because the BH bearer is terminated at the m-CU-UP, the donor-CU and the m-CU-CP must negotiate the QoS parameters and the transport layer (TNL) to be configured between the m-CU-UP and the donor-DU. This will correspond to an R17 partial migration, where F1 can be routed via the topology of the target donor between the source CU and the target donor-DU.

[0100] To further reduce the protocol overhead in the radio interface, header compression may be performed for F1-U. Since UE F1-U and SDAP' are configured by m-CU, there may be implementation-dependent options to perform header compression. In addition, the protocol layers used for F1-U may be non-standard, where for example the GTP layer is a modified protocol except that it explicitly distinguishes UE bearers carried over the backhaul link.

[0101] The advantages of the proposed mobile IAB / VMR vehicle mobile relay structure may be at least as follows:

[0102] Allows minimization / optimization or at least reduction / improvement of the need to access RAN (donor) functionality and upgrade IAB support; most enhancements will be implemented in dedicated functions / entities (i.e. m-CU and mobile IAB nodes)

[0103] Topology adaptation (mobile IAB node HO, migration), i.e. BH link change, is limited to a single hop and will not affect accessing UEs as long as the m-CU remains unchanged

[0104] If the mobile IAB node is served by a node of the IAB network, no routing reconfiguration is required in the fixed part of the IAB network

[0105] The serving access node does not have to support all IAB functions; only minor upgrades are required to the traditional RAN (which may include a large number of CU / DU nodes) which usually do not need to support wireless backhaul

[0106] There is no routing on the mobile BH link; there is no BAP in the mobile IAB-node or serving node DU, and no routing (re)configuration during mobility / migration

[0107] Flexibility to apply to various use cases and network deployment scenarios; this is partly due to (near) transparency into the access RAN

[0108] refer to Figure 2 and 3 In the description of the illustrated embodiment, the following functions are explained:

[0109] - Mapping of UE DRB to BH DRB

[0110] The input to the SDAP layer is usually a QoS flow from the UPF user plane function; here the input is F1-U carrying UE DRBs. Therefore, based on the current standard, it is not possible to map a QoS flow to a (BH) bearer at SDAP.

[0111] - Aggregate UE DRBs into BH DRBs. This is desirable because the number of LCID logical channel IDs may become limited on the BH link

[0112] An embodiment of a mobile IAB for solving the above problems may have the following specific features:

[0113] m-CU:

[0114] Can act as a secondary node (SN) for m-IAB nodes

[0115] Can be added by the donor CU in the standard SN addition process with respect to UE DRBs. m-CU acts as a MN master node towards the CN (UE bearer configuration, QoS flows, etc.), but acts as a SN auxiliary node towards the donor (for BH connections) Maps F1-U (e.g. using GTP TEID tunnel endpoint identifier) ​​to (multiple) BH DRBs, the m-CU-CP configures the m-CU-UP for DL ​​mapping Sends F1-U / BH DRB mapping to the m-IAB Initiates BH DRB setup (addition) or modification whenever it is needed to accommodate changing UE traffic (UE DRBs) using SN Modification Required messages

[0116] Donor-CU:

[0117] During the IAB Node Integration process, the "UE-Type" of the connecting device becomes known (= mobile IAB-Node, or IAB-Node supporting BH over DRB);

[0118] o Determine the donor-CU behavior in the following stages (SN addition, F1-C forwarding)

[0119] Act as MN for m-IAB node, add m-CU as SN

[0120] ·Terminate IAB-MT RRC

[0121] Allows the m-CU to initiate the setup and modification of BH DRBs in the form of SN terminated MCG bearers (where MCG is the IAB-MT to donor radio link)

[0122] Standard operation when receiving a required SN modification

[0123] Trigger the donor DU to (re)configure the RLC bearer of the BH DRB between the donor DU and the m-IAB-MT (standard operation)

[0124] Separate and forward CP (F1-C) services between m-IAB-DU and m-CU-CP according to Rel.17IAB CP-UP

[0125] m-IAB-Node:

[0126] Receive F1-U / BH DRB mapping from m-CU

[0127] Receive F1-U configuration for each UE DRB from m-CU

[0128] UL: Map F1-U of (multiple) UE DRBs to (multiple) BH DRBs based on configured F1-U / BH DRB mapping

[0129] It should be noted that although the embodiments are particularly effective for mobile m-IAB nodes which suffer from the above-mentioned problems, they are also applicable to fixed IAB nodes.

[0130] The basis of the embodiment is a DC dual connectivity operation, where the donor CU adds the m-CU as a secondary node. This can be done during the mobile IAB-node integration process, such as Figure 4 As shown. Initially, the IAB-MT behaves like a normal UE establishing a connection with the network (Phase 1). If this is the power-on situation, the IAB-MT registers with the network and performs normal procedures with the Core Network (CN), such as authentication, identification, etc. The service donor becomes aware of the "UE type", in this case a mobile IAB-node. With this knowledge, the donor assumes that the control plane (CP) of the mobile IAB-DU, i.e. F1-C, is routed to the mCU via the donor through MT RRC signaling and XnAP signaling. The donor can be pre-configured with information about the m-CU with which the mobile IAB-node is to communicate when it connects to the donor. This information may also come from OAM (Operation, Administration and Maintenance) as part of the node configuration data. The Xn connection can be established in advance between the donor and the m-CU.

[0131] The IAB-MT may establish a PDU session (Phase 2) to download configuration data from the OAM (Phase 3). The data path in this phase may be routed via the donor CU-UP.

[0132] In phase 4, F1 between the mCU and the IAB-DU is established using standard F1 procedures. As described above, messages are transmitted in RRC messages between the IAB-MT and the donor, and in XnAP messages between the donor and the m-CU.

[0133] In stage 5 of the integration process, the donor adds the m-CU as a secondary node (SN) for the intended SN terminated backhaul bearer. The SN Add Request-Message may optionally include a default set of backhaul (BH) data bearers (DRBs) over which UE traffic may be transmitted over the BH link. The SN Add process is a standard process using existing messages. The process is configured for transmission of UL / DL UP tunnels between the m-CU-UP and the donor DU; messages 5-2 and 5-9 (for m-CU-UP) and 5-4 and 5-8 (for donor DU). At the end of the process, the IAB-MT has configured the MCG primary cell group with an SN terminated bearer with a tunnel configured for transmission directly between the donor-DU and the m-CU-UP. The IAB node is now ready to activate (multiple) IAB-DU cells and accept UE access and traffic via (multiple) serving cells.

[0134] Figure 5 It shows how the UE connection is established and how the data bearers are configured when accessing via a mobile IAB-node. In phase 1, the UE accesses the cell normally and performs the required routines with the CN, such as for authentication, security, etc. Since the m-CU controls the mobile IAB-DU, the RRC signaling is sent through the m-CU-CP, which also forwards NAS messages to or from the CN.

[0135] For data connections, the UE may initiate a PDU Session Establishment (1). The CN processes the request in a standard manner and sends a PDU Session Request to the m-CU (via the AMF). The UP part of the m-CU (m-CU-UP) is configured with the new bearer(s) to be established, and tunnel information (to the UPF / CN and the UL TNL (Transport Network Layer) for the m-CU-UP) is exchanged between the m-CU-CP and the m-CU-UP.

[0136] The m-CU is the SN which can initiate (SN terminate) the modification of the BH DRB (6). This is required in case the service requested by the UE requires a change in the BH configuration. The procedure for SN modification uses standard signalling. The donor sends an SN modification confirmation indicating the accepted modification(s) (11).

[0137] The IAB-DU is configured with new bearer(s) (12). The F1-U TNL information is provided to the IAB-DU (12) for UL data and to the m-CU-CP (14).

[0138] Mapping of (multiple) UE F1-U tunnels to (multiple) BH DRBs:

[0139] -DL: m-CU-CP configures the mapping using the Bearer Context Modification Request (E1) message (17), where DL TNL information (for IAB-DU) is also included.

[0140] -UL: The m-CU-CP configures the mapping to the IAB-DU using the UE Context Modification Request (F1AP) message (19).

[0141] The UE bearers on the access link are configured with conventional signaling (21-24). The procedure in the RAN is completed with the m-CU-CP sending a PDU Session Response message to the CN to complete the procedure also in the CN.

[0142] Example of modification of messages via mobile IAB node to support UE bearer configuration: UL TNL mapping for m-CU-UP and IAB-DU in Figure 6 is displayed.

[0143] Figure 7 A wireless communication network according to an embodiment is shown. Figure 7 A vehicle 12 including a plurality of user devices 10 and a relay node 20 is schematically shown. The relay node 20 is an IAB mobile node and acts as a relay for packets between the user devices 10 and the 5G core network. This has the advantage that when the vehicle 12 passes between cells, the handover from the cell is performed via the relay node 20, rather than each of the individual user devices 10 that need to perform the handover. The relay node 20 is connected to the base station 30 when it is within the cell of the base station 30. The base station 30 is a donor IAB node 30 and treats the relay node 20 as a user device with the same protocol stack. However, the donor becomes aware of the type of access device during the integration process, thereby identifying this node as a relay IAB node. In response to this knowledge, the donor node 30 can initiate a secondary node addition process by sending a secondary node addition request message to the centralized node 40, requesting it to become a secondary node.

[0144] The donor 30 has devices associated with it, one or more of which may be within the node itself or at a location in the cloud that is remote from the node. The devices may be divided into different units, which may be physically different or logically different. They may include a control unit 32 configured to control the control plane and a control unit 34 and distributed units 36 configured to control the user plane. They may include a processor and a memory for storing instructions to control the processor to control the device. The control unit may be a virtual function in the cloud, or they may include circuit systems configured to perform these functions. The node 30 includes a sending and receiving circuit system for sending and receiving CP and UP data from other nodes and user equipment, and is controlled by signals from units 32, 34 and 36. The control plane control unit 32 generates a secondary node addition request.

[0145] The centralized or anchor node 40 also has associated therewith an apparatus which may be within the node 40 itself where the transmit and receive circuitry is located, or may be remote from the node 40, possibly in the cloud. The apparatus includes a control unit 42 for the control plane and a control unit 46 for the user plane. Again, these may be physically distinct units, or they may be only logically distinct, each configured to perform a specific function. The units may include a processor and a memory for storing instructions to control the processor to control the apparatus.

[0146] The donor IAB node 30 and the anchor node 40 may have a wired Xn backhaul link 52 .

[0147] A user plane control unit 46 associated with the centralized node 40 includes a mapping circuit system 47 for mapping at least one user equipment bearer associated with a UE connected to the relay node to at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the relay node, and the at least one backhaul bearer is between the relay node 20 and the centralized node 40. This mapping is performed in the user plane control unit 46, but is controlled by the control circuit system 43 in the control plane unit 42.

[0148] Once the mapping has been generated, the control circuit system 43 within the control plane entity 42 of the device supporting the centralized node 40 controls the node 40 to send the mapping in the form of a UE context modification request, which includes the uplink F1 tunnel mapped to the backhaul DRB to the relay node 20. The relay node 20 responds with a context modification response indicating that it has received the mapping and that it will perform the mapping when it receives a data packet. In this way, a data path available for UE data is established between the relay node 20 and the centralized node 40.

[0149] The relay node includes a mapping circuit system configured to map at least one UE bearer to at least one backhaul bearer based on a mapping in a message received from the anchor node or centralized node 40. This provides a backhaul link in the form of an F1-U tunnel between the relay node and the anchor node or centralized node 40. That is, the UE bearer is carried in the F1-U tunnel between the relay node 20 and the anchor network node 40, and this is configured as a backhaul link for the two nodes.

[0150] There may be a GTP tunneling protocol tunnel between the m-CU-UP 46 and the donor DU 36. Transport Network Layer (TNL) parameters (for the GTP tunnel) are exchanged with the SN Add Request / Response or SN Modify Request / Confirm-messages. The GTP tunnel endpoint will then be known at the donor-CU 32 (= tunnel endpoint at the m-CU-UP 46 for UL data) and at the m-CU-UP 46 for DL ​​data (tunnel endpoint at the donor-DU 36).

[0151] Those skilled in the art will readily recognize that the steps of the various methods described above can be performed by a programmed computer.Herein, some embodiments are also intended to encompass program storage devices, such as digital data storage media, which are machine or computer readable and encode machine executable or computer executable instruction programs, wherein the instructions perform some or all of the steps of the above methods.The program storage device can be, for example, a digital memory, a magnetic storage medium (such as a disk and a tape), a hard drive, or an optically readable digital data storage medium.Embodiments are also intended to encompass computers programmed to perform the steps of the above methods.The term "non-transient" used herein is a limitation of the medium itself (i.e., tangible, rather than a signal), rather than a limitation of data storage persistence (e.g., RAM and ROM).

[0152] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0153] (a) hardware circuit implementation only (e.g., implementation only in analog and / or digital circuitry) and

[0154] (b) a combination of hardware circuitry and software such as (where applicable):

[0155] (i) a combination of analog and / or (multiple) digital hardware circuits and software / firmware and

[0156] (ii) any portion of hardware processor(s) (including digital signal processor(s)), software and memory(s) with software that work together to enable a device (such as a mobile phone or server) to perform various functions and (c) hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s) that require software (e.g., firmware) to operate, but where the software is not required for operation, the software may not be present.

[0157] This definition of circuitry applies to all uses of the term in this application, including in any claims. As a further 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. The term "circuitry" also covers, for example, 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, if applicable to the particular claim element.

[0158] Although embodiments have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed.

[0159] Features described in the preceding description may be used in combinations other than the combinations explicitly described.

[0160] Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

[0161] Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.

[0162] While an effort has been made in the foregoing description to call attention to those features of the example embodiments which are regarded as particularly important, it should be understood that the applicant claims protection for any patentable feature or combination of features mentioned above and / or shown in the accompanying drawings, whether or not particular emphasis has been given thereto.

Claims

1. An apparatus for supporting wireless communication at a network node, the apparatus 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 apparatus or the network node to at least perform: Mapping at least one UE bearer associated with a user equipment UE to at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the network node, and the at least one backhaul bearer is between a relay node and the network node; as well as A message is sent to the relay node indicating the mapping of the at least one UE bearer to the at least one backhaul bearer.

2. The device according to claim 1, wherein: The mapping includes: an association between the at least one UE bearer and the at least one backhaul bearer, and the message includes a UE context modification request.

3. The apparatus according to claim 1 or 2, wherein the at least one UE bearer is carried in an F1-U tunnel between the relay node and the network node.

4. An apparatus according to any preceding claim, wherein the apparatus is caused to perform: in response to a first request to act as an auxiliary network node, acting as the auxiliary node.

5. An apparatus according to any preceding claim, wherein the apparatus is caused to perform: in response to receiving a request to terminate the at least one backhaul bearer, terminating the at least one backhaul bearer.

6. The apparatus according to claim 4 or 5, wherein the first request is received from a further network node.

7. The apparatus of claim 6, wherein the apparatus or network node is further configured to perform: generating a request requesting the further network node to establish or modify a configuration for a radio connection for the at least one backhaul bearer; and The request is sent to the further network node.

8. The apparatus of claim 7, wherein the request to the further network node to establish or modify comprises: The secondary node modifies the required message.

9. An apparatus as claimed in any preceding claim, wherein the relay node comprises a mobile IAB node.

10. The apparatus of any preceding claim, wherein the mapping of the at least one UE bearer to the at least one backhaul bearer comprises: The multiple UE bearers are mapped to one backhaul bearer among the backhaul bearers.

11. An apparatus according to any preceding claim, comprising: A control plane entity and a user plane entity, the control plane entity being configured to perform: providing information associated with the mapping of the at least one UE bearer to the at least one backhaul bearer to the user plane entity, the user plane entity being configured to perform the mapping based on the information.

12. According to any of the preceding claims, the device or network node is also configured to perform: receiving a response to the message indicating the mapping from the relay node, the response confirming that the message indicating the mapping is received at the relay node, and confirming that the mapping of the at least one UE bearer to the at least one backhaul bearer is performed at the relay node.

13. An apparatus for supporting wireless communications at a relay network node for relaying packets between a user equipment and a network node, the apparatus 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 device or the relay network node to at least perform: receiving a message from a network node indicating a mapping between at least one UE bearer and at least one backhaul bearer, wherein the at least one UE bearer is between a UE and the network node, and the at least one backhaul bearer is between the relay node and the network node; as well as In response to receiving the message, the mapping of the at least one UE bearer to the at least one backhaul bearer is performed based on the received message.

14. The device according to claim 13, wherein: The mapping comprises an association between the at least one UE bearer and the at least one backhaul bearer, and the message comprises a UE context modification request.

15. The apparatus according to claim 13 or 14, wherein the at least one UE bearer is carried in an F1-U tunnel between the relay node and the network node, and the mapping of the at least one UE bearer to the at least one backhaul bearer comprises: The at least one F1-U tunnel is mapped to the at least one backhaul bearer.

16. An apparatus according to any one of claims 13 to 15, wherein the apparatus or relay network node is configured to perform: sending a response to the message indicating the mapping, the response confirming that the mapping of the at least one UE bearer to the at least one backhaul bearer is performed at the relay node.

17. A wireless communication system comprising a relay network node according to any one of claims 13 to 16, the relay network node being configured to relay packets between a user equipment and a network node according to any one of claims 1 to 12.

18. A method for supporting wireless communication at a network node, the method comprising: Mapping at least one UE bearer associated with a user equipment UE to at least one backhaul bearer, wherein the at least one UE bearer is between the UE and the network node, and the at least one backhaul bearer is between a relay node and the network node; as well as A message is sent to the relay node indicating the mapping of the at least one UE bearer to the at least one backhaul bearer.

19. The method according to claim 18, further comprising: In response to a first request to serve as a secondary network node, serving as the secondary node.

20. The method according to claim 18 or 19, comprising: In response to receiving the request to terminate the at least one backhaul bearer, the at least one backhaul bearer is terminated.

21. The method according to claim 19 or 20, comprising: The first request is received from a further network node.

22. The method according to claim 21, comprising: generating a request requesting the further network node to establish or modify a configuration for a radio connection for the at least one backhaul bearer; as well as The request is sent to the further network node.

23. A method for supporting wireless communications at a relay network node for relaying packets between a user equipment and the network node, the method comprising: receiving a message from a network node indicating a mapping between at least one UE bearer and at least one backhaul bearer, wherein the at least one UE bearer is between a UE and the network node, and the at least one backhaul bearer is between the relay node and the network node; as well as In response to receiving the message, the mapping of the at least one UE bearer to the at least one backhaul bearer is performed based on the received message.

24. A computer program comprising computer instructions which, when executed by at least one processor on a device, are configured to control the device to perform the method according to any one of claims 18 to 22.

25. A computer program comprising computer instructions which, when executed by at least one processor on a device, are configured to control the device to perform the method according to claim 23.

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