CN116508278A

CN116508278A - Resource efficiency enhancement for IAB networks

Info

Publication number: CN116508278A
Application number: CN202080107360.5A
Authority: CN
Inventors: D·科齐奥尔; 许翔; G·德卡罗; I·凯斯基塔罗; M·莱蒂拉; S·图尔蒂南
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2020-09-21
Filing date: 2020-09-21
Publication date: 2023-07-28
Also published as: WO2022056932A1

Abstract

An IAB network node that is part of a RAN in communication with a UE performs the following operations: receiving a configuration with information indicating which data is to be replicated in the downlink direction and to be consolidated in the uplink direction; in the downlink direction, for a single DRB associated with the UE, receiving first data over the backhaul link, determining that the first data is indicated as data to be replicated, replicating the first data into a plurality of downlink traffic streams, and transmitting the plurality of downlink traffic streams towards the UE; and in the uplink direction, receiving second data from the UE over the plurality of uplink traffic flows, determining that the second data is indicated as data to be combined, combining the second data into a single traffic flow, and forwarding the single traffic flow over the backhaul link towards the network. Additional techniques use IAB DUs and CU nodes.

Description

Resource efficiency enhancement for IAB networks

Technical Field

The exemplary embodiments herein relate generally to wireless communication networks and, more particularly, to networks with Integrated Access and Backhaul (IAB).

Background

In a cellular communication system, the term "backhaul" is used to denote a communication path from a base station to a base station or from a base station to a core network. Typically, the backhaul from the base station to the core network uses very high speed communications, such as fiber optic communications. The backhaul between base stations was initially wired, but recently there has been a trend towards wireless backhaul between base stations in some cases.

For example, the third generation partnership project (3 GPP) Rel-16 (release 16) specification introduced Integrated Access and Backhaul (IAB) features. Because of this feature, user traffic may be relayed through a wireless interface (e.g., uu) between two relay nodes, e.g., referred to as IAB nodes. The relay may take place over one or more hops (referred to as air interface segments).

While the IAB feature is beneficial, it also presents challenges. For example, a base station may use the same spectrum or wireless channel to serve mobile devices (referred to as User Equipment (UE)) within its coverage area as well as provide backhaul connections for other base stations. This and other resource challenges can result in resource inefficiency.

Disclosure of Invention

This section is intended to include an example, and is not intended to be limiting.

In an exemplary embodiment, a method is disclosed that includes performing, in an integrated access and backhaul network node that is part of a radio access network in communication with a user equipment, the following: receiving a configuration with information indicating which data is to be replicated in the downlink direction and combined in the uplink direction; in the downlink direction, for a single data radio bearer associated with the user equipment, receiving first data over the backhaul link, determining that the first data is indicated as data to be replicated, replicating the first data into a plurality of downlink traffic streams, and transmitting the plurality of downlink traffic streams towards the user equipment; and in the uplink direction, receiving second data from the user equipment over the plurality of uplink traffic flows, determining that the second data is indicated as data to be combined, combining the second data into a single traffic flow, and forwarding the single traffic flow over the backhaul link towards the network.

Additional exemplary embodiments include a computer program comprising code for performing the method of the previous paragraph when the computer program is run on a processor. The computer program according to this paragraph, wherein the computer program is a computer program product comprising a computer readable medium having computer program code embodied therein for use with a computer. Another example is a computer program according to the paragraph, wherein the program is directly loadable into the internal memory of a computer.

An example apparatus includes one or more processors and one or more memories including computer program code. The one or more memories and the computer program code are configured to, with the one or more processors, cause the apparatus to perform operations comprising: receiving a configuration with information indicating which data is to be replicated in the downlink direction and combined in the uplink direction; in the downlink direction, for a single data radio bearer associated with the user equipment, receiving first data over the backhaul link, determining that the first data is indicated as data to be replicated, replicating the first data into a plurality of downlink traffic streams, and transmitting the plurality of downlink traffic streams towards the user equipment; and in the uplink direction, receiving second data from the user equipment over the plurality of uplink traffic flows, determining that the second data is indicated as data to be combined, combining the second data into a single traffic flow, and forwarding the single traffic flow over the backhaul link towards the network.

An exemplary computer program product includes a computer readable storage medium having computer program code embodied therein for use with a computer. The computer program code includes code for: receiving a configuration with information indicating which data is to be replicated in the downlink direction and combined in the uplink direction; in the downlink direction, for a single data radio bearer associated with the user equipment, receiving first data over the backhaul link, determining that the first data is indicated as data to be replicated, replicating the first data into a plurality of downlink traffic streams, and transmitting the plurality of downlink traffic streams towards the user equipment; and in the uplink direction, receiving second data from the user equipment over the plurality of uplink traffic flows, determining that the second data is indicated as data to be combined, combining the second data into a single traffic flow, and forwarding the single traffic flow over the backhaul link towards the network.

In another exemplary embodiment, an apparatus includes means for: receiving a configuration with information indicating which data is to be replicated in the downlink direction and combined in the uplink direction; in the downlink direction, for a single data radio bearer associated with the user equipment, receiving first data over the backhaul link, determining that the first data is indicated as data to be replicated, replicating the first data into a plurality of downlink traffic streams, and transmitting the plurality of downlink traffic streams towards the user equipment; and in the uplink direction, receiving second data from the user equipment over the plurality of uplink traffic flows, determining that the second data is indicated as data to be combined, combining the second data into a single traffic flow, and forwarding the single traffic flow over the backhaul link towards the network.

In an exemplary embodiment, a method is disclosed that includes receiving data for a user equipment at an integrated access and backhaul donor distributed element node, and determining, by the integrated access and backhaul donor distributed element node, that the data is associated with a data radio bearer to be replicated. The method also includes adding, by the integrated access and backhaul donor distributed element node, a replication indication associated with the data, and forwarding, by the integrated access and backhaul donor distributed element node, the data and the added replication indication toward the integrated access and backhaul node to perform replication of the data.

An example apparatus includes one or more processors and one or more memories including computer program code. The one or more memories and the computer program code are configured to, with the one or more processors, cause the apparatus to perform operations comprising: receiving data for a user equipment at an integrated access and backhaul donor distributed element node; determining, by the integrated access and backhaul donor distributed element node, that the data is associated with a data radio bearer to be replicated; adding, by the integrated access and backhaul donor distributed element node, a replication indication associated with the data; and forwarding, by the integrated access and backhaul donor distributed element node, the data and the added replication indication towards the integrated access and backhaul node to perform replication of the data.

An exemplary computer program product includes a computer readable storage medium having computer program code embodied therein for use with a computer. The computer program code includes: code for receiving data for a user equipment at an integrated access and backhaul donor distributed element node; determining, by the integrated access and backhaul donor distributed element node, that the data is associated with a data radio bearer to be replicated; adding, by the integrated access and backhaul donor distributed element node, a replication indication associated with the data; and forwarding, by the integrated access and backhaul donor distributed element node, the data and the added replication indication towards the integrated access and backhaul node to perform replication of the data.

In another exemplary embodiment, an apparatus includes means for: receiving data for a user equipment at an integrated access and backhaul donor distributed element node; determining, by the integrated access and backhaul donor distributed element node, that the data is associated with a data radio bearer to be replicated; adding, by the integrated access and backhaul donor distributed element node, a replication indication associated with the data; and forwarding, by the integrated access and backhaul donor distributed element node, the data and the added replication indication towards the integrated access and backhaul node to perform replication of the data.

In an exemplary embodiment, a method is disclosed that includes performing, at an integrated access and backhaul donor control unit in a network, the following: determining that a traffic flow of a user equipment is to be replicated by an integrated access and backhaul network node in a network; and configuring at least one of the following for the integrated access and backhaul network node: information that the traffic flow of the user equipment in the downlink direction is to be duplicated and information that the traffic flow of the user equipment in the uplink direction is to be combined.

An example apparatus includes one or more processors and one or more memories including computer program code. The one or more memories and the computer program code are configured to, with the one or more processors, cause the apparatus to perform operations comprising: the following is performed at an integrated access and backhaul donor control unit in a network: determining that a traffic flow of a user equipment is to be replicated by an integrated access and backhaul network node in a network; and configuring at least one of the following for the integrated access and backhaul network node: information that the traffic flow of the user equipment in the downlink direction is to be duplicated and information that the traffic flow of the user equipment in the uplink direction is to be combined.

An exemplary computer program product includes a computer readable storage medium having computer program code embodied therein for use with a computer. The computer program code includes: code for performing, at an integrated access and backhaul donor control unit in a network, the following: determining that a traffic flow of a user equipment is to be replicated by an integrated access and backhaul network node in a network; and configuring at least one of the following for the integrated access and backhaul network node: information that the traffic flow of the user equipment in the downlink direction is to be duplicated and information that the traffic flow of the user equipment in the uplink direction is to be combined.

In another exemplary embodiment, an apparatus includes means for: the following is performed at an integrated access and backhaul donor control unit in a network: determining that a traffic flow of a user equipment is to be replicated by an integrated access and backhaul network node in a network; and configuring at least one of the following for the integrated access and backhaul network node: information that the traffic flow of the user equipment in the downlink direction is to be duplicated and information that the traffic flow of the user equipment in the uplink direction is to be combined.

Drawings

In the drawings:

FIG. 1 is a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced;

FIG. 2 illustrates an overall IAB architecture, wherein FIG. 2A illustrates an IAB node configuration using CA mode with NGC, and FIG. 2B illustrates an IAB node configuration using EN-DC;

FIG. 3 illustrates parent and child node relationships for an IAB node;

FIG. 4 illustrates protocol stacks for supporting the F1-U protocol (left side) and the F1-C protocol (right side);

fig. 5 illustrates routing and BH RLC channel selection on the BAP sublayer;

fig. 6 illustrates a resource inefficiency problem in an IAB network for carrying radio bearers configured with PDCP packet duplication using Carrier Aggregation (CA) (scenario 1) and Dual Connectivity (DC) (scenario 2);

Fig. 7 is a block diagram illustrating a copy processing function in an access IAB node for CA-based copy according to the first exemplary embodiment;

fig. 8 is a flowchart of a first embodiment, in which a UE is configured with CA replication; and

fig. 9 is a block diagram illustrating a copy discarding function in an intermediate IAB node for DC-based copy according to a second embodiment.

Detailed Description

Abbreviations that may appear in the specification and/or drawings are defined below at the end of the detailed description section.

The term "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this detailed description are provided as exemplary embodiments to enable persons skilled in the art to make or use the invention without limiting the scope of the invention which is defined by the claims.

Example embodiments herein describe techniques for resource efficiency enhancement for IAB networks. Additional description of these techniques is given after describing the system in which the exemplary embodiments may be used.

Turning to FIG. 1, a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced is shown. A User Equipment (UE) 110, a plurality of IAB nodes 170 and 170-1, and a network element(s) 190 are shown. In fig. 1, a User Equipment (UE) 110 is in wireless communication with a wireless network 100. The UE is wireless and typically a mobile device that can access a wireless network. UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected by one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optic or other optical communications devices, etc. One or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123.UE 110 includes a control module 140, control module 140 including one or both of portions 140-1 and/or 140-2, which may be implemented in a variety of ways. The control module 140 may be implemented in hardware as the control module 140-1, such as being implemented as part of one or more processors 120. The control module 140-1 may also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, the control module 140 may be implemented as a control module 140-2, the control module 140-2 being implemented as computer program code 123 and executed by the one or more processors 120. For example, the one or more memories 125 and the computer program code 123 may be configured to, with the one or more processors 120, cause the user device 110 to perform one or more of the operations as described herein. UE 110 communicates with IAB node 170-1 via wireless link 111 and IAB node 170 communicates with IAB donor node 170 via backhaul link 176.

Two IAB network nodes 170 and 170-1 are shown, wherein the IAB network node 170 is denoted as donor node in one example. More details regarding possible network structures using the IAB network nodes 170, 170-1 (and additional IAB nodes) are provided below, but for simplicity, it is assumed that the circuitry between the IAB network nodes 170, 170-1 is similar. That is, there will be a processor, memory, and computer program code (described below) in each of the IAB network nodes 170 and 170-1, and the operations performed by the respective network nodes 170/170-1 may be implemented in hardware, software, or a combination of both, as described below. Thus, only the circuitry of the IAB network node 170 is shown.

It should also be noted that Central Unit (CU) 196 and Distributed Units (DUs) are shown as part of IAB donor node 170. However, this is for ease of illustration, e.g., the DU and CU are typically separate in a cloud RAN implementation. Thus, the DU 195 and CU 196 portions of the IAB network node 170 may be physically separate and each have their own processor/memory/computer program code. It is further noted that an IAB DU may also be referred to as an IAB DU node, since in case of a DU being separate from a CU each of the DU and CU may be its own node. As used herein, the integrated access and backhaul network node may be an IAB node 170-x (where "x" is 1, 2, … …) or an IAB DU node 195.

The IAB network node 170/170-1 is a base station providing access to the wireless network 100 through a wireless device, such as the UE 110, and may be a donor node (170) or an IAB node (170-1). The donor node 170 is typically connected to a core network, here illustrated in part using network element(s) 190. This connection is shown as link 131, link 131 typically being a fiber optic link, but may be any other suitable link.

For example, the IAB network node 170 may be a base station of 5G (also referred to as New Radio (NR)). In 5G, the IAB node 170 may be an NG-RAN node, defined as a gNB or NG-eNB. As a clarification, in a non-independent (NSA) network, the IAB may be deployed with EN-DC (EUTRAN NR dual connectivity) connections, where the serving node of the IAB node may be an eNB (master node). However, the eNB provides only a control interface and the Backhaul (BH) (e.g., data) is carried over the NR leg of the DC. The gNB is a node that provides NR user plane and control plane protocol termination towards the UE and is connected to the 5GC (e.g., network element(s) 190) via an NG interface. The NG-eNB is a node providing E-UTRA user plane and control plane protocol termination towards the UE and is connected to the 5GC via an NG interface. The NG-RAN node may include a plurality of gnbs, which may also include a Central Unit (CU) (gNB-CU) 196 and a Distributed Unit (DU) (gNB-DU), of which DU 195 is shown. Note that a DU may include or be coupled to a Radio Unit (RU) and control the RU. The gNB-CU is a logical node hosting the RRC, SDAP and PDCP protocols of the gNB or the RRC and PDCP protocols of the en-gNB. There is an F1-C connection between the CU and the DU, through which the CU controls the DU using the F1AP protocol. The gNB-CU terminates the F1 interface connected to the gNB-DU. The F1 interface is shown as reference numeral 198, although reference numeral 198 also shows links between remote elements of the IAB network node 170 and centralized elements of the IAB network node 170, such as between the gNB-CU 196 and the gNB-DU 195. For CU 196 connected to DU 195-1, link 198-1 is al. The gNB-DU is a logical node that hosts the RLC, MAC and PHY layers of the gNB or en-gNB, and its operation is controlled in part by the gNB-CU. One gNB-CU supports one or more cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the F1 interface 198 connected to the gNB-CU. Note that DU 195 is considered to include transceiver 160, e.g., as part of an RU, but some examples of this may have transceiver 160 as part of a separate RU, e.g., under control of DU 195 and connected to DU 195. The IAB node 170 may also be an eNB (evolved node B) base station for LTE (long term evolution), or any other suitable base station.

The IAB node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces ((N/W I/F) 161, and one or more transceivers 160 interconnected by one or more buses 157. Each of the one or more transceivers 160 includes a receiver Rx 162 and a transmitter Tx 163. One or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153.CU 196 may include processor(s) 152, memory 155, and network interface 161. Note that DU 195 may also contain its own memory (and corresponding computer program code) and processor(s), and/or other hardware, but these are not shown.

The IAB node 170 comprises a control module 150, the control module 150 comprising one or both of the parts 150-1 and/or 150-2, which may be implemented in a variety of ways. The control module 150 may be implemented in hardware as the control module 150-1, such as being implemented as part of one or more processors 152. The control module 150-1 may also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, the control module 150 may be implemented as a control module 150-2, the control module 150-2 being implemented as computer program code 153 and executed by one or more processors 152. For example, the one or more memories 155 and the computer program code 153 are configured, with the one or more processors 152, to cause the IAB node 170 to perform one or more of the operations as described herein. Note that the functionality of control module 150 may be distributed, such as between DU 195 and CU 196, or implemented in DU 195 alone.

One or more network interfaces 161 communicate over a network, such as via links 176 and 131. Two or more IAB nodes 170, 170-1 communicate using, for example, link 176. The link 176 may be wireless and may implement, for example, an NR Uu interface.

The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optic or other optical communication devices, wireless channels, etc. For example, one or more transceivers 160 may be implemented as a Remote Radio Head (RRH) 195 for LTE, or a Distributed Unit (DU) 195 for a gNB implementation of 5G, where other elements of the IAB node 170 may be physically in different locations than the RRH/DU, and one or more buses 157 may be implemented in part as, for example, fiber optic cables or other suitable network connections for connecting other elements of the IAB node 170 (e.g., central Units (CUs), gNB-CUs) to the RRH/DU 195. Reference numeral 198 also indicates those suitable network link(s).

IAB node 170-1 comprises DU 195-1 and MT 70. These will be described in more detail below. The DU 195-1 and MT 70 may be implemented in hardware or software or some combination of these. That is, for ease of reference, only CU 196 is shown with processor(s) 152 and memory(s) 155. However, any DU or MT may also have this circuitry. Note that only one IAB node 170-1 is shown, but there may be two or more such nodes (as shown below), and the term "170-x" (where x=1, 2, 3, … …) is used below to indicate any of these nodes.

The wireless network 100 may include one or more network elements 190, which network elements 190 may include core network functionality and provide connectivity to a data network 191, such as a telephone network and/or a data communications network (e.g., the internet), via one or more links 181. Such core network functions for 5G may include access and mobility management function(s) (AMF) and/or User Plane Function (UPF) and/or session management function(s) (SMF). Such core network functions of LTE may include MME (mobility management entity)/SGW (serving gateway) functions. These are merely exemplary functions that network element(s) 190 may support, and note that both 5G and LTE functions may be supported. The IAB node 170 is coupled to a network element 190 via a link 131. Link 131 may be implemented, for example, as an NG interface for 5G, or an S1 interface for LTE, or other suitable interface for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N/W I/F) 180 interconnected by one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured, with the one or more processors 175, to cause the network element 190 to perform one or more operations.

Wireless network 100 may implement network virtualization, which is a process of combining hardware and software network resources and network functions into a single software-based management entity (virtual network). Network virtualization involves platform virtualization, which is typically combined with resource virtualization. Network virtualization may be categorized as external network virtualization, which combines many networks or portions of networks into one virtual unit, or internal network virtualization, which provides network-like functionality for software containers on a single system. Note that to some extent, the virtualized entity resulting from network virtualization is still implemented using hardware such as processors 152 or 175 and memories 155 and 171, and that such virtualized entity also produces technical effects.

Computer readable memories 125, 155, and 171 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The computer readable memories 125, 155, and 171 may be means for performing a memory function. Processors 120, 152, and 175 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital Signal Processors (DSPs), and processors based on a multi-core processor architecture, as non-limiting examples. Processors 120, 152, and 175 may be components for performing functions, such as controlling UE 110, IAB node 170, and other functions described herein.

In general, various embodiments of the user device 110 may include, but are not limited to, cellular telephones such as smartphones, tablet computers, personal Digital Assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, modem device-equipped vehicles for wireless V2X (vehicle-to-all) communications, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback devices having wireless communication capabilities, internet appliances (including internet of things IoT devices) that allow wireless internet access and possibly browsing, ioT devices having wireless communication tablets with sensors and/or actuators for automated applications, and portable units or terminals that incorporate combinations of such functions.

Having introduced one suitable but non-limiting technical context for the practice of the exemplary embodiments, the exemplary embodiments will now be described in more detail.

As previously described, due to the IAB feature, user traffic may be relayed between two relay nodes, referred to as IAB nodes 170, 170-1, over a wireless interface (Uu) (e.g., link 176 in fig. 1). The relay may be performed on one or more hops. The overall IAB architecture is shown in fig. 2. Fig. 2 illustrates an overall IAB architecture, where fig. 2A illustrates an IAB node configuration using CA mode with NGC, and fig. 2B illustrates an IAB node configuration using EN-DC. The source of this figure is 3GPP TS 38.300V16.2.0 (2020-07), see FIG. 4.7.1-1.

In FIG. 2A, there are two AMF/UPFs 190-1 and 190-2, a gNB 210, an IAB donor node (e.g., gNB) 170, and two IAB nodes 170-1, 170-2. Interfaces NG, xn, NR Uu and F1 are shown. In fig. 2B, there are two MME/S-PGWs 190-3 and 190-4, an eNB 220, an eNB as MeNB, an IAB donor node (e.g., sgNB) 170, and two IAB nodes 170-1, 170-2. Interfaces S1, X2, S1-U, X2-C, LTE Uu, NR Uu, and F1 are shown.

There are two types of nodes in the IAB architecture, an IAB donor 170 and an IAB node 170-1. The IAB donor node 170 is a node with a wired connection to the core network. IAB donor 170 includes a donor CU 196 portion that hosts RRC, SDAP, and PDCP layers of the NR air interface, and a donor DU 195 portion that hosts RLC, MAC, and PHY layers of the NR air interface stack. On the other hand, the IAB node 170-1 is composed of IAB-DU 195-1 and IAB-MT 70 parts, wherein the IAB DU 195 is connected to the donor CU 196 part using an F1 interface and provides wireless connection for the access UE 110 and for the IAB-MT 70 of the child node or other next hop IAB node 170-1 (i.e. those served by the IAB-DU), while the IAB-MT 70 is responsible for providing wireless backhaul connection to the upstream IAB node 170-x or IAB donor 170, or may have other connections besides backhaul connection, e.g. PDU sessions for OAM (operation and maintenance) traffic. In the IAB, a downstream node connected to the IAB node is called a child node thereof. The upstream node of the IAB node is called its parent node. The IAB node may be connected to up to two parent nodes simultaneously using an NR dual connectivity mode to provide topology redundancy for the backhaul link. These dependencies are given in fig. 3.

Fig. 3 illustrates parent and child node relationships of an IAB node. The source of this figure is 3GPP TS 38.300V16.2.0 (2020-07), see FIGS. 4.7.1-2. In this example, parent nodes 170A and 170B include IAB-DUs 195A and 195B. The IAB node 170-1 comprises an IAB-MT 70 and an IAB-DU 195-1. The parent nodes 170A and 170B are upstream relative to the IAB node 170-1 and the child nodes 170-2A, 170-2B and 170-2C are downstream. The child nodes 170-2A, 170-2B and 170-2C include corresponding IAB-MTs 70-1A, 70-1B and 70-1C. The interface between these nodes is the NR Uu interface.

To enable wireless backhaul, a new protocol layer, called Backhaul Adaptation Protocol (BAP), is also introduced in the air interface between the IAB donor DU and the IAB node and between the two IAB nodes. The protocol stack for carrying user plane and control plane data over a two-hop IAB chain is given in fig. 4. The source of this figure is 3gpp TS 38.300 and fig. 4 shows the protocol stacks for supporting the F1-U protocol (left side) and the F1-C protocol (right side).

In this example, IAB donor 170 has CU 196 with layers GTP-U and UDP, and has DU 195 with layer IP, BAP, RLC, MAC and PHY. In the illustrated stack, the lowest layer is the PHY (physical) layer, and the highest layer is the GTP-U layer. There is a BH NR RLC channel between the IAB donor 170 and the IAB node 1 170-1. In fig. 4, the F1-U interface is between the IAB donor 170 and the IAB node 2 170-2. This is transparent and is relayed only by the IAB node 1 170-1. In fig. 4, there is also an F1-U that terminates in the IAB node 1 but is not shown in the figure. The IAB node 1 170-1 has an IAB-MT 70 with layer BAP, RLC, MAC and PHY, and an IAB-DU 195-1 with layer BAP, RLC, MAC and PHY. There is an F1-U interface and a BH NR RLC channel between IAB node 1 170-1 and IAB node 2 170-2. The F1-U interface terminates in IAB-DU 195-2 of IAB node 2 170-2, IAB-DU 195-2 having GTP-U, UDP and IP layers. The BH NR RLC channel terminates at IAB-MT 70-1, which IAB-MT 70-1 includes layer BAP, RLC, MAC and PHY.

BAP is responsible for mapping upper layer traffic (F1-U, F1-C or non-F1 traffic) onto the BH RLC channel using a channel mapping configuration that is provided to the IAB node and IAB donor DUs using F1AP and/or RRC protocols. Traffic is mapped based on information included in the header of higher layer protocols such as IP or GTP-U. The specific mapping is configured to:

1) For each F1-U GTP-U tunnel;

2) For non-UE related F1AP messages;

3) UE-related F1AP messages for each UE; and

4) For non-F1 traffic.

Another responsibility of BAP is to determine the destination node of the higher layer packet and route the BAP packet within the IAB network based on the BAP address and BAP path identifier carried in the BAP header and the routing configuration provided by the F1AP protocol. The BAP header is generated in the traffic originating IAB node 170-x (in this example "x" is 1 or 2) (for upstream traffic) and in the IAB donor DU 195 for downstream traffic. When a BAP packet arrives at IAB node 170-x, the node examines the BAP address included in the BAP header to determine if the address matches its own BAP address (configured earlier by donor CU 196). If so, it is provided to higher layers in the IAB node for further processing. Otherwise, IAB node 170-x examines its routing table and BH RLC channel map configuration to determine the link and BH RLC channel in which BAP packets should be routed. An example of this operation is given in fig. 5.

Fig. 5 illustrates routing and BH RLC channel selection on the BAP sublayer. The source is 3GPP TS 38.300. Routing from the previous hop to the next hop is performed by selection of the BH RLC channel. Ingress BH links and ingress BH RLC channels, and egress BH links and egress BH RLC channels are shown.

The initial IAB network is expected to be deployed in a controlled and planned manner, such as:

1) The fixed location of the IAB node;

2) Comprehensive network and radio planning prior to deployment;

3) Use of directional antennas; and/or

4) And (5) line-of-sight insurance.

In such a deployment, the BH link is much more reliable than the access radio link between the UE and the IAB node. The BH network may also be protected via path redundancy, i.e., in the event of a BH link failure, BH traffic may be routed via another BH link or an IAB segment. On the other hand, for an access UE, one of the methods for increasing the service reliability is the use of PDCP packet duplication, such as:

1) Carrier Aggregation (CA) replication, wherein the same packet is transmitted through different cells of the same gNB;

2) Dual Connectivity (DC) duplication, wherein the same packet is sent through cells belonging to two different gnbs;

3) In Rel-15, replication over two cells is possible, while Rel-16 allows replication over up to four cells; and/or

4) In Rel-16, CA replication can be configured with DC replication.

Packet duplication is described in section 16.1.3 of 3gpp TS 38.300.

When PDCP duplication is configured for the radio bearer of the UE, a separate GTP-U tunnel is established for each RLC channel involved in the duplication. This means that the data is not only duplicated over the air interface, but also over the F1 or Xn interface in the RAN network. While replication is reasonable for the UE's access link, e.g., in a fixed IAB deployment, it is not required on the BH link, which the inventors consider reliable and do not require replication for a fixed IAB network. Thus, there is little benefit in replicating packets over the BH link while reducing the resource efficiency and capacity of the network. This may also cause the donor DU 195 and the IAB node 170-1 near the donor DU 195 to become bottlenecks of the IAB system. This problem is presented in fig. 6 for two different scenarios.

Scenario 1 610 involves CA replication between a single IAB node 170-2 and UE 110. Donor CU 196, donor DU 195, IAB node #1 170-1 and IAB node #2170-2 are shown, and CA replication 620 performed over wireless links 613 and 614 is shown. The wasting of resources 650 occurs because dashed line 611 and solid line 612 indicate two paths, each path carrying the same data. Path 611 is for a first GTP-u#1 path and path 612 is for a second GTP-u#2 path. Paths 611 and 612 carry the same user data over the BH link. The copy and GPT tunnel terminates at the access IAB node 170-2. Over the Uu interface (via links 613 and 614) there are two RLC/MAC/PHY connections over the CA carrier, while PDCP is end-to-end between UE 110 and IAB donor node 196. In fact, if other paths 611 and 612 are assumed to be error free or low error, only IAB #2170-2 needs to use wireless links 613 and 614 to perform replication. Similar problems apply to the uplink when the UE sends uplink data to the donor CU 196 via the access node (iab#2 170-2), the intermediate IAB node (iab#1 170-1) and the donor DU 195. In one example, wireless links 613 and 614 may be used for a primary cell (PCell) and a secondary cell (SCell), respectively.

Scenario 2 630 involves DC replication between two IAB nodes (170-2A and 170-2B) and UE 110. Donor CU 196, donor DU 195, IAB node #1170-1, and IAB nodes #2170-2A and 170-2B are shown, and DC copy 640 performed using wireless links 613 and 614 is shown. The wasting of resources 650 occurs because dashed line 611 and solid line 612 indicate two paths, each path carrying the same data. Path 612 is for the first GTP-u#1 path and path 611 is for the second GTP-u#2 path. Only IAB #1170-1 needs to use its paths 616, 617 to perform the replication, IAB nodes #2170-2A and #3 170-2B will send the replication via radio links 613 and 614, respectively. This again assumes that the other paths 611 and 612 are error free or low error. Similar problems apply to the uplink when the UE sends uplink data to the donor CU 196 via the access nodes (iab#2 170-2, iab#3 170-2B), the intermediate IAB node (iab#1 170-1) and the donor DU 195. In one example, wireless links 613 and 614 may be used for primary secondary cell (PSCell) and primary cell (PCell), respectively.

For non-IAB copy operations, it was previously proposed to use a single GTP-U tunnel over the Xn interface between the primary node and the secondary node, both nodes participating in the copy. This proposal has not been adopted in the 3GPP standard. It should be noted that in the case of an IAB, the previously proposed techniques cannot be reused directly because additional mechanisms are required to make the replication and duplicate drops in the IAB node. Furthermore, this problem is more important for the IAB, as the traffic is replicated over the air interface where radio resources are scarce. For the non-IAB use case discussed earlier, the problem is less severe, because in a RAN network the traffic is only replicated on wired interfaces, which typically have high capacity.

In addition to the other problems described above and others, it is also proposed herein to address this problem by introducing a mechanism that can avoid unnecessary duplicate packets in the IAB node 170-x or the IAB donor DU 195 before carrying the packets over the unnecessary backhaul link, while still allowing the packets to be duplicated in the necessary IAB network nodes and over the air interface. First, a summary is provided, followed by additional details.

In an exemplary embodiment, as an overview, the mechanism is based on the following.

1) Donor CU 196 provides "copy configuration" for the UE's Radio Bearers (RBs) for which packet copying is enabled. The configuration information is provided using one of the following options (a) to (c).

a) Within the backhaul configuration of the IAB donor DU (for DL traffic) and/or the access IAB node (for UL traffic). Upon receiving such a configuration, the IAB donor DU or IAB node adds a copy indication to the BAP header of the packet related to the copied radio bearer. Note that an "access" IAB node is a node to which a UE is attached. The IAB node may be an access IAB node for some UEs and may be a conventional BH IAB node for other UEs not directly attached to the IAB node but attached through a sub-IAB node. For accessing the IAB node, this may also be performed within the F1-U tunnel configuration or as part of the UE radio bearer configuration. When the F1-C packet needs to be duplicated, configuration in the access IAB node may be performed during a gNB-DU configuration update procedure or a gNB-CU configuration update procedure.

b) The traffic should be duplicated for the access UE by the BH RLC channel indicating the bearer traffic. In this case, the IAB donor DU 195 and/or IAB node 170-x identifies that the packet belongs to a duplicate radio bearer based on the ingress or egress BH RLC channel of the packet.

Based on this configuration, the IAB network node (donor DU or IAB node) detects the relevant traffic and adds a copy indication.

In the DL direction, the indication may additionally include information about the number of copies needed and/or which access logical channels should be used for packet delivery to the UE.

2) Based on the copy indication, the IAB node performs the following operations.

a) In the DL direction, when a packet marked with a copy indication is received (e.g., carried in the BAP header or derived based on its ingress BH RLC channel), the IAB node 170-x or IAB-MT 70-x function of the IAB node 170-x indicates that the packet should be copied over the air interface to a function responsible for packet delivery to the UE (e.g., to a transmission portion of an upper layer or BAP sublayer in the IAB node, etc.). Upon receipt of such an indication, the IAB node 170-x (or IAB-DU 195-x function of the IAB node 170-x) replicates the packet over the air interface.

b) In the UL direction, in response to receiving a packet over a radio bearer configured with duplication, or based on a previous configuration marked with a duplication indication, the IAB node 170-x performs a duplicate discard function, which is typically performed only in the PDCP layer hosted by the donor CU 196.

In addition, the discard function may be performed based on the PDCP Sequence Number (SN) of the packet, which means that the IAB node needs to have basic PDCP functions, such as a PDCP copy discard function and a PDCP window function. The discard function will keep track of the received PDCP sequence number. However, when all PDCP SNs have been used, the PDCP layer will reuse the SNs starting from 0 (zero) and use a window to ensure that there is no confusion. This window should be used in the IAB node to know the location of the current SN in the PDCP SN window.

The copy related function may reside in the IAB-MT or IAB-DU. Consider the following. For the UL, it is more interesting to detect and discard copies in the IAB-DU once they are received for the UE. For DL, the Rx part of the BAP layer may indicate the need for a copy to the upper layer, and the upper layer will handle this (upper layer refers to the upper layer in the IAB-DU).

An overview has now been provided, providing further details. In a first embodiment, the UE is configured with CA-based replication. Fig. 7 depicts an exemplary implementation in which a copy handling function 710 is incorporated in an access IAB node 170-2 to handle access UE radio bearers configured with CA-based copying. The figure also shows a PCell (primary cell) 730 and an SCell (secondary cell) 720 formed by IAB 2 170-2. Note that each of PCell 730 and SCell 720 has its own RLC and MAC layers, which in the CA example are used to perform packet duplication. The layers and other blocks in the elements of fig. 7 may be means for performing those corresponding functions and may be implemented in hardware or software as described above with respect to the processor and memory of UE 110 and each of IAB donor node 170 and IAB node 170-x.

For traffic sent in the DL direction, the following exemplary alternatives are presented.

1) In a first alternative:

a) Donor CU 196 configures to donor DU 195 a specific traffic flow to be replicated for the UE, e.g., identified by specific IP header content (e.g., IP address and/or port number and/or Differentiated Services Code Point (DSCP) and/or IPv6 flow label, etc.). Donor CU 196 may also configure donor DU 195 with specific traffic flows to replicate for the UE, e.g., identified by specific GTP-U header content (e.g., GTP-U tunnel endpoint identifiers).

b) Later, when donor DU 195 receives downlink data from donor CU 196, the DU uses the previously received configuration to check the IP header content and/or GTP-U header content. In the case of a match, donor CU 196 includes a "duplicate indication" of the packet associated with the flow in the BAP header. The indication may additionally include information about the number of copies needed and/or which access logical channels should be used for packet delivery to the UE.

c) When such a BAP PDU arrives at the destination IAB node, the BAP layer indicates to the upper layers that the packet should be duplicated over the air interface.

d) The duplicate handling function 710 in the IAB node 170-2 ensures that BAP SDUs are duplicated and provided for transmission to multiple logical channels based on the configuration.

2) In a second alternative:

a) Donor CU 196 configures at destination IAB node 170-2 the particular BH RLC channel or particular traffic of the particular BH RLC channel identified by at least one of a backhaul radio link control channel identity, a route identification, a tunnel endpoint identifier, or any field of a backhaul adaptation protocol header, etc., with a copy indication. In this case, the donor DU 195 maps the incoming packets to the RLC channel as usual according to instructions of the CU.

b) Duplicate handling function 710 at IAB node 170-2 ensures that every packet arriving on a certain BH RLC channel is duplicated over the air interface.

c) The indication may be passed to upper layers via the BAP sub-layer or may be left to the IAB node implementation.

For traffic sent in the UL direction, the following is one possible implementation.

1) Similar to DL, IAB node 170-2 is configured with information from donor CU 196, i.e. a certain UE DRB is configured with replication. Such configuration may be part of a BH traffic mapping configuration or part of an F1 tunnel configuration for radio bearer configuration, e.g., during an F1AP UE context setup/modification procedure of the UE.

2) UE 110 sends data to access IAB node 170-2 using two or more RLC entities/logical channels.

3) The IAB node 170-1 checks the identity of packets belonging to the replicated traffic flow, e.g. PDCP SNs, and discards PDCP PDUs if packets with such SNs are received earlier. Thus, only one copy of the user data is sent to IAB#1 170-1 and further to donor CU 196. This merges the two traffic flows from the UE into a single uplink traffic flow with information from only one traffic flow of the UE.

An exemplary flow chart of the first embodiment is given in fig. 8. The figure further illustrates the operation of one or more exemplary methods, the results of execution of computer program instructions embodied on a computer readable memory, the functions performed by the logic implemented in hardware, and/or the interconnecting components for performing the functions in accordance with the exemplary embodiments. It is assumed that the operations in fig. 8 are performed at least in part by UE 110 under control of control module 140 or by IAB network node 170 or 170-x under control of control module 150.

In step 1 of fig. 8, there is a DRB establishment with CA PDCP duplication. This is between UE 110 and IAB node 2 170-2 and then also between IAB node 2 170-2 and donor CU 196 via IAB node 1 170-1 and donor DU 195. Donor CU 196 transmits a message to donor DU 195 in step 2, the message including the backhaul mapping configuration of the DL traffic stream, and the replication indication. Donor CU 196 also sends this message to IAB node 170-2 in step 3 to configure replication.

Block 810 indicates signaling that occurs for the processing of duplicate DRBs in the DL. Block 820 indicates signaling that occurs for the handling of duplicate DRBs in the UL. Block 810 is first described.

In block 810, donor CU 196 sends (step 4) a message including DL user data of the replicated DRB. The donor DU 195 detects user data that needs to be duplicated based on the configuration received in step 2. The donor DU 195 adds (step 5) a copy indication to the BAP header (in this example) based on the BH mapping configuration. This corresponds to the first alternative above, where the donor DU 195 includes a "duplicate indication" of the packets associated with the flow in the BAP header.

The donor DU 195 performs (step 6) BAP PDU delivery with an indication for IAB node 2 via an intermediate IAB node (e.g., IAB node #1 170-1). That is, the delivery terminates at IAB node 170-2. In the case of carrier aggregation, the always-on IAB node performs replication, so the intermediate IAB node does not receive any instruction from the CU about replication, and the BAP header does not indicate that the intermediate node should replicate. In this case, the access IAB node is IAB node 2 170-2. The IAB node 170-2 performs (step 7) detection of a copy indication in the BAP header and then performs (step 8) providing a copy indication to the upper layer. Steps 7 and 8 are performed by a duplicate handling function 710, which duplicate handling function 710 sends a duplicate indication to at least the RLC layer in PCell 730 and SCell 720. The RLC layer then determines that the packet to which the DRB relates is being duplicated and performs a known duplication procedure. The IAB node 170-2 performs packet delivery using the PCell 730 in step 9 and packet duplicate delivery using the SCell 720 in step 10. If the packet has been successfully received via another path, the UE discards the packet. According to the examples herein, UE behavior is not affected for these operations.

For block 820, which indicates signaling that occurs for the processing of duplicate DRBs in the UL, UE 110 is in CA mode. Thus, the UE transmits UL packets on the primary RLC channel of the duplicate DRBs, e.g., via PCell 730. This occurs in step 11. In step 12, the UE sends the same UL packet on the secondary RLC channel of the duplicate DRB, e.g., via SCell 720. Duplication is for PDCP packets (in the case of CA) sent to the RLC channel on different carriers. PDCP packets are sent over a main link and duplicate packets are sent over a second link, and vice versa.

Steps 13 through 15 may be performed by copy processing function 710. In step 13, the duplicate processing function 710 performs a duplicate detection function, and in step 14, duplicate packets are discarded. As described above, the IAB node 170-2 checks the PDCP SNs of packets belonging to the duplicate traffic stream (e.g., via the duplicate processing function 710) and discards PDCP PDUs if packets with such SNs are received earlier. The remaining single packets are delivered to an upper layer, e.g., BAP, for transmission (step 15). See step 16. This means that duplicate traffic flows from the UE are combined into a single traffic flow.

In a second embodiment, the UE is configured with DC-based replication. In case the access UE is configured with DC-based replication, the replica processing function has to reside in one of the intermediate IAB nodes. In the example of fig. 9, this is the IAB node 170-1 for this particular configuration of three IAB nodes 170-1, 170-2, and 170-3. However, this is merely exemplary. This situation is shown in fig. 9. The figure also shows a PCell (primary cell) 930 formed by the IAB node 170-2 and a PSCell (primary secondary cell) 920 formed by the IAB 2 170-3. Note that each of PCell 930 (for IAB node 170-2) and PCell 920 (for IAB node 170-3) has its own RLC and MAC layers for performing packet duplication in the DC example. The layers and other blocks in the elements of fig. 9 may be means for performing those corresponding functions and may be implemented in hardware or software as described above with respect to the processor and memory of UE 110 and each of IAB donor node 170 and IAB nodes 170-2/170-3. The methods described below also apply when UE 110 connects directly with IAB 170-1 without IAB 170-2 or without IAB 170-3. When the IAB 170-2 is not present and the IAB170-3 is present, the PCell (primary cell) 930 is formed by the IAB node 170-1 and the PSCell (primary secondary cell) 920 is formed by the IAB 170-3. When the IAB 170-2 is present and the IAB170-3 is not present, a PCell (primary cell) 930 may be formed by the IAB node 170-2 and a PSCell (primary secondary cell) 920 may be formed by the IAB 170-1.

For traffic sent in the DL direction, the following is one possible implementation.

1) The packets do not need to be replicated over the BH link, which is common to the paths between each of the IAB nodes 170-2/170-3 involved in the DC replication.

a) For both paths, the packet only needs to be replicated by the last common node (IAB node 1 170-1 in the example shown).

b) Donor CU 196 knows the topology and therefore knows that the packet's IAB node 170-1 should be replicated. Donor CU 196 configures to donor DU 195 a specific traffic flow to be replicated for the UE, e.g., identified by specific IP header content (e.g., IP address and/or port number and/or Differentiated Services Code Point (DSCP) and/or IPv6 flow label, etc.). Donor CU 196 may also configure donor DU 195 with specific traffic flows to replicate for the UE, e.g., identified by specific GTP-U header content (e.g., GTP-U tunnel endpoint identifiers). Donor CU 196 configures donor DU 195 to add a copy indication and IAB node 170-1 to perform a copy based on the copy indication. That is, in the exemplary embodiment, donor CU 196 configures IAB node 170-1 to enable replication using the replication indication, and then, when data having the replication indication arrives, IAB node 171-1 performs replication.

2) The replication indication (added by the donor DU 195, which is the first BAP node in the DL direction) may be carried in the BAP header, similar to the CA case. However, for the DC case, the BAP should also indicate the IAB node that should perform duplication of the packet:

a) In addition to the BAP address of the destination IAB node, the address of the IAB node 170-x (IAB node 171-1 in the example of fig. 9) used to perform the replication may be carried in the BAP header (e.g., added by the donor DU according to the configuration from the donor CU). Alternatively, the BAP header may not be changed, but donor CU 196 configures the IAB node to perform replication of the specific BAP PDU, e.g., when performing the configuration in step (b) below. In this alternative, nothing is added to the regular BAP header, and the donor DU simply sets the path ID according to the instructions of the CU.

b) A special path ID (identity) or indication may be configured in the IAB node, which indicates that the BAP PDU is to be duplicated together with additional information about which links are to be used for transmission. In this example, the CU configures this to the IAB node that performs the replication. The donor DU typically sets the path ID only according to the configuration of the CU. This may be accomplished by configuring two routing entries of the same routing ID for the IAB node, optionally with a "replication indication". The route ID typically includes a BAP address and a path ID. In this case, the path ID portion of the routing ID indicates that the packet should be duplicated and there will be two BAP addresses in the BAP header. In this example, the route ID has the BAP address of the destination node (170-2A or 170-2B), but there is an additional BAP address indicating the node (170-1) performing the replication.

c) The IAB node 170-1 may be further configured to modify the routing ID in the BAP header before forwarding the packet further. In other words, since the copies are pointing to different end IAB nodes, the BAP address of the packet may be modified accordingly. CU 196 may configure IAB node 170-1 or IAB node 170-1 may be preconfigured to decide to modify the header itself because the copy is sent to a different destination IAB node 170-2/3. The replication indication may be carried in the BAP header. If so, the donor DU adds the indication.

d) Since the packets received by both the final IAB nodes, IAB node 170-2 and IAB node 170-3, will include the same IP packet (same IP address, etc.), the IP nodes need to be configured such that neither of them discards the corresponding IP packet.

For traffic sent in the UL direction, the following is one possible implementation:

1) Similar to the CA case, the duplicate should be discarded by the IAB node, in which case it would be the first public node 170-1 of the UL path of the duplicate packet. That is, in the depicted case, the common node is IAB 1 170-1.

2) In order for the IAB node 170-1 to identify a copy, the following operations are performed:

a) Similar to in the CA case, the IAB node (e.g., IAB 1 170-1) is configured (e.g., by donor CU 196) with information about which BH RLC channels and/or routing IDs and/or GTP-U TEIDs are used to carry duplicate packets. Since there may be multiple GTP-U tunnels between the access IAB and the donor CU that share the same BH RLC channel/routing ID, IAB 1 170-1 may be provided with additional information, such as TEID, to identify the relevant UL traffic.

b) In the case that IPsec is not configured, the IAB node 170-1 may snoop the BAP SDUs, read its PDCP SNs, check if packets with the same PDCP SN for the radio bearer have been sent before, and if so, discard such duplicate packets.

c) If encryption is enabled for the F1 tunnel of the bearer that is duplicated for the bearer:

i) It is not possible for the IAB node to check the PDCP SN directly in the PDCP PDU.

ii) to address this problem, an access IAB node handling a logical channel configured for duplicate radio bearers (e.g., IAB 2 170-2 and IAB 3 170-3 in the depicted case) copies the GTP-U TEID and PDCP SN into the BAP header. If F1-C needs to be considered, the access IAB node 170-2/3 copies the SCTP flow identifier and flow sequence number into the BAP header. Alternatively, the F1 tunnel may terminate in an intermediate node (IAB node 170-1 in this case) that handles the copy function.

The replica processing function 910 combines the replica traffic streams from the UE into a single traffic stream. That is, only a single traffic flow (e.g., an individual packet created using duplicate packets received via IAB nodes 170-2 and 170-3) is sent by IAB node 171-1 to the parent node.

It should also be noted that current F1-U security is peer-to-peer, i.e., one sender encrypts GTP-U and one receiver decrypts the received GTP-U packet. In the case presented, the destination of the DL F1-U is set to IAB 2 170-2 and encrypted with the IAB 2-CU security key. Even though IAB 1 170-1 may copy DL F1-U and send it to IAB 3 170-3, IAB 3 cannot decrypt DL F1-U packets encrypted using IAB 2's key. A similar security mechanism as in MBMS may be used so that both IAB 2 and IAB 3 may decrypt DL F1-U packets.

Now that the first and second exemplary embodiments have been described, examples relate to potential implementations of copy discarding functionality, such as copy processing functionality 710/910.

In the UL, simple push-based window handling and dropping functions may be implemented in the node responsible for avoiding duplication. Since the node does not know the HFN of the PDCP packet, the node may rely on the SN of the packet. The node should also know the window size of the PDCP entity for the DRBs. The node has a variable rx_next_sn initialized to 0 (zero).

When a PDCP packet with a given rcv_sn is received, it is calculated modulo window_size 2, where the Window size is the reception Window of the PDCP entity of the DRB. The following procedure may be performed as indicated by the pseudo code.

1> if rx_next_sn < = rcv_sn < rx_next_sn+window_size:

2> if PDCP with the same SN has been received, dropping the packet; otherwise, the packet is transmitted and the state sn=rcv_sn is stored;

2> set rx_next_sn to rcv_sn+1, and reset the reception state of SN between rx_next_sn and rcv_sn;

1> otherwise: the packet is discarded (this should not occur if the PCDP packet is sent within Window size).

The following are additional examples.

Example 1. A method, comprising:

in an integrated access and backhaul network node that is part of a radio access network in communication with user equipment, performing the following operations:

receiving a configuration with information indicating which data is to be replicated in the downlink direction and to be consolidated in the uplink direction;

in the downlink direction, for a single data radio bearer associated with the user equipment, receiving first data over the backhaul link, determining that the first data is indicated as data to be replicated, replicating the first data into a plurality of downlink traffic streams, and transmitting the plurality of downlink traffic streams towards the user equipment; and

in the uplink direction, receiving second data from the user equipment over the plurality of uplink traffic flows, determining that the second data is indicated as data to be combined, combining the second data into a single traffic flow, and forwarding the single traffic flow over the backhaul link towards the network.

Example 2. The method of example 1, wherein:

the integrated access and backhaul network node is connected with the user equipment via carrier aggregation; and is also provided with

The sending of the plurality of traffic streams towards the user equipment and the receiving of the second data from the user equipment over the plurality of traffic streams is performed by the integrated access and backhaul network node using carrier aggregation.

Example 3. The method of example 1, wherein:

the integrated access and backhaul network node is connected to the user equipment via a dual connection, via a wireless link between the integrated access and backhaul network node and the user equipment, and via a second backhaul link between the integrated access and backhaul network node as a parent node and one other integrated access and backhaul network node as a child node of the parent node;

transmitting the plurality of downlink traffic streams towards the user equipment includes transmitting respective ones of the plurality of downlink traffic streams via the wireless link and the second backhaul link; and is also provided with

Receiving second data from the user equipment over the plurality of uplink traffic flows further includes receiving the second data via the wireless link and the second backhaul link.

Example 4. The method of example 1, wherein:

the integrated access and backhaul network node as a parent node is connected to the two integrated access and backhaul nodes as child nodes to provide dual connectivity to the user equipment;

transmitting the plurality of downlink traffic streams towards the user equipment comprises: transmitting respective ones of the plurality of downlink traffic streams to respective ones of the child nodes via the second backhaul link; and is also provided with

Receiving second data from the user equipment over the plurality of uplink traffic streams further comprises: second data is received from respective ones of the child nodes via the second backhaul link.

Example 5 the method of any one of examples 1 to 4, wherein:

determining that the first data is indicated to be replicated further comprises: determining, for data received over the backhaul link, that the data has an associated replication indication and that the data is first data that should be replicated; and is also provided with

Copying is performed only for the first data determined to have an associated copy indication.

Example 6 the method of any one of examples 1 to 5, further comprising determining that the first data is indicated to be replicated in a downlink direction or the second data is indicated to be combined based on at least one of:

a replication indication;

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

Example 7 the method of any one of examples 1 to 6, further comprising receiving a configuration from the integrated access and backhaul donor node for identifying duplication or merging, the configuration comprising one or more of:

Backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

Example 8 the method of example 1, wherein determining that the second data is indicated as data to be merged comprises checking a backhaul adaptation protocol header of the second data to determine whether at least one of a tunnel endpoint identifier or a packet data convergence protocol sequence number indicates that the second data should be merged or whether at least one of a stream control transport protocol stream identifier or a stream sequence number indicates that the second data should be merged.

Example 9 the method of any one of examples 1 to 8, wherein the integrated access and backhaul network node is an integrated access and backhaul node.

Example 10 the method of any one of examples 1 to 8, wherein the integrated access and backhaul network node is an integrated access and backhaul donor distributed element node.

Example 11. A method, comprising:

receiving data for a user equipment at an integrated access and backhaul donor distributed element node;

determining, by the integrated access and backhaul donor distributed element node, that the data is associated with a data radio bearer to be replicated;

Adding, by the integrated access and backhaul donor distributed element node, a replication indication associated with the data; and

forwarding, by the integrated access and backhaul donor distributed element node, the data and the added replication indication towards the integrated access and backhaul node to perform replication of the data.

Example 12 the method of example 11, wherein determining, by the integrated access and backhaul donor distributed element node, that the data is associated with the data radio bearer to be replicated comprises: configuration information is received from the integrated access and backhaul central unit node that a particular traffic stream is to be replicated for the user equipment and the data is part of the particular traffic stream.

Example 13. The method of example 12, wherein the configuration information includes particular internet protocol header content indicating that the particular traffic stream is to be replicated for the user device.

Example 14 the method of any one of examples 11 to 12, wherein replicating the indication includes: duplicate indications in the backhaul adaptation protocol header for packets associated with a particular traffic flow.

Example 15 the method of any of examples 11-14, wherein the integrated access and backhaul node is an access node for a user equipment, the access node using transmissions to the user equipment via a plurality of wireless links in carrier aggregation.

Example 16 the method of example 15, wherein adding, by the integrated access and backhaul donor distributed element node, the replication indication associated with the data further comprises including in the backhaul adaptation protocol header a replication indication for packets related to the traffic flow to be replicated.

Example 17. The method of example 16, wherein the indication of duplication in the backhaul adaptation protocol header includes information regarding a number of duplicates required and/or which access logical channels should be used for packet delivery to the user equipment.

Example 18 the method of any one of examples 11-14, wherein the integrated access and backhaul node uses transmissions from the at least one integrated access and backhaul child node to the user equipment via the plurality of backhaul links in a dual connection, wherein the integrated access and backhaul node is a parent node of the at least one integrated access and backhaul child node.

Example 19. The method of example 15, wherein:

adding, by the integrated access and backhaul donor distributed element node, a replication indication associated with the data further comprises including in a backhaul adaptation protocol header a replication indication for packets related to the traffic flow to be replicated; and is also provided with

The method includes the integrated access and backhaul donor distributed element node indicating an integrated access and backhaul node that should perform replication of data.

Example 20. The method of example 19, wherein the integrated access and backhaul node indicating that replication of the data should be performed is performed by including an address of the integrated access and backhaul node in a backhaul adaptation protocol header.

Example 21. The method of example 19, wherein the integrated access and backhaul node indicating that replication of the data should be performed is performed by adding a path identification and a backhaul adaptation protocol address to the data, the path identification indicating that the packet should be replicated, and the backhaul adaptation protocol address indicating an address of the integrated access and backhaul node for performing the replication.

Example 22. A method, comprising:

at an integrated access and backhaul donor control unit in a network, performing the following operations:

determining that a traffic flow of a user equipment is to be replicated by an integrated access and backhaul network node in a network; and

configuring at least one of the following for an integrated access and backhaul network node: information that the traffic flow of the user equipment in the downlink direction is to be replicated and information that the traffic flow of the user equipment in the uplink direction is to be combined.

Example 23 the method of example 22, wherein the integrated access and backhaul network node is an integrated access and backhaul donor distributed element node, and wherein the information comprises at least one of the following information for traffic flow in a downlink direction:

an internet protocol address;

differentiated service code point values;

a stream label;

a field of an internet protocol header; or (b)

Tunnel endpoint identifiers.

Example 24 the method of example 23, wherein the information that the traffic flows of the user equipment in the uplink direction are to be combined further indicates to the integrated access and backhaul donor distributed element node that the plurality of traffic flows of the user equipment in the uplink direction are to be combined into a single traffic flow, and wherein the information comprises: at least one of the following information of traffic flows in uplink direction:

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

Example 25 the method of example 22, wherein:

the integrated access and backhaul network node is an integrated access and backhaul node;

the information to be replicated by the user equipment traffic flow in the downlink direction comprises at least one of the following information of the traffic flow in the downlink direction:

Backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

Any field of the backhaul adaptation protocol header; and

the information to be combined by the user equipment traffic flows in the uplink direction comprises at least one of the following information of the traffic flows in the uplink direction:

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

Example 26. A computer program comprising code for performing the method according to any of examples 1 to 25 when the computer program is run on a computer.

Example 27, an apparatus comprising means for performing the method of any of examples 1-25.

Example 28, an apparatus, comprising: one or more processors; and one or more memories including computer program code, wherein the one or more memories and the computer program code are configured, with the one or more processors, to cause the apparatus to perform the method of any of examples 1-25.

Without limiting the scope, interpretation, or application of the claims that follow in any way, a technical effect and advantage of one or more of the example embodiments disclosed herein is improved resource efficiency over the backhaul link. Another technical effect and advantage of one or more of the example embodiments disclosed herein is increased IAB network capacity. Another technical effect of one or more of the example embodiments disclosed herein is that, at the same time, additional reliability of the access link may still be ensured due to duplication.

The term "circuitry" as used in this application may refer to one or more or all of the following:

(a) Hardware-only circuit implementations (such as implementations in analog and/or digital circuitry only)

(b) A combination of hardware circuitry and software, such as (as applicable):

(i) Combination of analog and/or digital hardware circuit(s) and software/firmware, and

(ii) Any portion of the hardware processor(s) with software, including the digital signal processor(s), software, and memory(s), work together to cause 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 of microprocessor(s), that require software (e.g., firmware) to operate, but may not exist when software is not required to operate.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also encompasses hardware-only circuitry or a processor (or multiple processors) or a portion of a hardware circuit or processor and its attendant software and/or firmware implementations. For example, if applicable to the particular claim elements, the term circuitry also encompasses a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, a cellular network device, or other computing or network device.

Embodiments herein may be implemented in software (executed by one or more processors), hardware (e.g., application specific integrated circuits), or a combination of software and hardware. In an example embodiment, software (e.g., application logic, instruction set) is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" can be any medium or means that can contain, store, communicate, propagate, or transport the instructions for use by or in connection with the instruction execution system, apparatus, or device (such as a computer), an example of which is described and depicted, for example, in fig. 1. A computer-readable medium may include a computer-readable storage medium (e.g., memory 125, 155, 171, or other device) that may be any medium or means that can contain, store, and/or communicate instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. The computer-readable storage medium does not include a propagated signal.

The different functions discussed herein may be performed in a different order and/or simultaneously, if desired. Furthermore, one or more of the above-described functions may be optional or may be combined, if desired.

Although various aspects of the invention are set out in the independent claims, other aspects of the invention comprise other combinations of features of the above-described embodiments and/or the dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the claims.

It should also be noted herein that while the above describes example embodiments of the invention, these descriptions should not be viewed in a limiting sense. Rather, some changes and modifications may be made without departing from the scope of the invention as defined in the appended claims.

The following abbreviations that may appear in the specification and/or drawings are defined as follows:

3GPP: third generation partnership project

5G: fifth generation of

5GC: 5G core network

AMF: access and mobility management functions

BAP: backhaul adaptation protocol

BH: backhaul device

CA: carrier aggregation

CU: central unit

DC: dual connection

DL: downlink link

DRB: data radio bearer

DSCP: differential service code points

DU: distributed unit

eNB (or eNodeB): evolved node B (e.g., LTE base station)

EN-DC: E-UTRA-NR dual connectivity

En-gNB or En-gNB: providing NR user plane and control plane protocol termination towards a UE and acting as a node of a secondary node in EN-DC

E-UTRA: evolved universal terrestrial radio access, i.e. LTE radio access technology

gNB (or gNodeB): 5G/NR base station, i.e. a node providing NR user plane and control plane protocol termination towards the UE and connected to 5GC via NG interface

HFN: super frame number

GPRS: general packet radio service

GTP: GPRS tunnel protocol

GTP-U: GTP user plane

IAB: integrated access and backhaul

ID: identification mark

I/F: interface

IP: internet protocol

IPsec: internet protocol security

IPv6: internet protocol version 6

LTE: long term evolution

MAC: medium access control

MBMS: multimedia broadcast and multicast services

MgNB or MeNB: the master node, gNB or eNB in this example

MME: mobility management entity

MT: mobile terminated or mobile terminated

NG or NG: next generation

Ng-eNB or Ng-eNB: next generation eNB

NR: new radio

N/W or NW: network system

PCell: main cell

PDCP: packet data convergence protocol

PDCP SN: PDCP sequence number

PDU: protocol data unit

PHY: physical layer

RAN: radio access network

Rel: version of

RLC: radio link control

RRH: remote radio head

RRC: radio resource control

RU: radio unit

Rx: receiver with a receiver body

SCell: secondary cell

SCTP: flow control transmission protocol

SDAP: service data adaptation protocol

SDU: service data unit

SgNB or SeNB: auxiliary node, gNB or eNB

SGW: service gateway

SMF: session management function

SN: sequence number

TEID: tunnel endpoint identifier

TS: technical specification of

Tx: transmitter

UE: user equipment (e.g., wireless devices, typically mobile devices)

UL: uplink channel

UPF: user plane functionality

Claims

1. A method, comprising:

receiving a configuration having information indicating which data is to be replicated in the downlink direction and to be consolidated in the uplink direction;

in the downlink direction, for a single data radio bearer associated with the user equipment, receiving first data over a backhaul link, determining that the first data is indicated as data to be replicated, replicating the first data into a plurality of downlink traffic flows, and transmitting the plurality of downlink traffic flows towards the user equipment; and

in the uplink direction, receiving second data from the user equipment over a plurality of uplink traffic flows, determining that the second data is indicated as data to be combined, combining the second data into a single traffic flow, and forwarding the single traffic flow over the backhaul link towards the network.

2. The method according to claim 1, wherein:

The sending of the plurality of traffic flows towards the user equipment and the receiving of the second data from the user equipment over a plurality of traffic flows are performed by the integrated access and backhaul network node using the carrier aggregation.

3. The method according to claim 1, wherein:

transmitting the plurality of downlink traffic streams towards the user equipment comprises: transmitting respective ones of the plurality of downlink traffic flows via the wireless link and the second backhaul link; and is also provided with

Receiving second data from the user equipment over a plurality of uplink traffic streams further comprises: the second data is received via the wireless link and the second backhaul link.

4. The method according to claim 1, wherein:

the integrated access and backhaul network node as a parent node is connected to two integrated access and backhaul nodes as child nodes to provide dual connectivity to the user equipment;

transmitting the plurality of downlink traffic streams towards the user equipment comprises: transmitting respective ones of the plurality of downlink traffic streams to respective ones of the child nodes via a second backhaul link; and is also provided with

Receiving second data from the user equipment over a plurality of uplink traffic streams further comprises: the second data is received from respective ones of the child nodes via the second backhaul link.

5. The method of any one of claims 1 to 4, wherein:

The copying is performed only for the first data determined to have the associated copy indication.

6. The method of any one of claims 1 to 5, further comprising: determining that the first data is indicated to be replicated in the downlink direction or the second data is indicated to be consolidated based on at least one of:

A replication indication;

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

7. The method of any one of claims 1 to 6, further comprising: receiving a configuration from an integrated access and backhaul donor node for identifying duplication or merging, the configuration comprising one or more of:

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

8. The method of claim 1, wherein the determining that the second data is indicated as data to be combined comprises: checking a backhaul adaptation protocol header of the second data to determine whether at least one of a tunnel endpoint identifier or a packet data convergence protocol sequence number indicates: the second data should be merged or whether at least one of a stream control transmission protocol stream identifier or a stream sequence number indicates that the second data should be merged.

9. The method of any of claims 1 to 8, wherein the integrated access and backhaul network node is an integrated access and backhaul node.

10. The method of any of claims 1 to 8, wherein the integrated access and backhaul network node is an integrated access and backhaul donor distributed element node.

11. A method, comprising:

forwarding, by the integrated access and backhaul donor distributed element node, the data and the added replication indication towards an integrated access and backhaul node that is to perform the replication of the data.

12. The method of claim 11, wherein determining, by the integrated access and backhaul donor distributed element node, that the data is associated with a data radio bearer to be replicated comprises: configuration information is received from an integrated access and backhaul central unit node for a particular traffic stream to be replicated for the user equipment, and the data is part of the particular traffic stream.

13. The method of claim 12, wherein the configuration information comprises: indicating that the particular traffic flow is to be replicated for the particular internet protocol header content of the user device.

14. The method of any of claims 11 to 12, wherein the replication indication comprises: a duplicate indication in the backhaul adaptation protocol header for the packet associated with the particular traffic flow.

15. The method of any of claims 11 to 14, wherein the integrated access and backhaul node is an access node for the user equipment, the access node using transmissions to the user equipment via a plurality of wireless links in carrier aggregation.

16. The method of claim 15, wherein adding, by the integrated access and backhaul donor distributed element node, a replication indication associated with the data further comprises: a duplication indication for packets related to the traffic flow to be duplicated is included in the backhaul adaptation protocol header.

17. The method of claim 16, wherein the duplicate indication in the backhaul adaptation protocol header comprises: information about the number of copies needed, and/or which access logical channels should be used for packet delivery to the user equipment.

18. The method of any of claims 11 to 14, wherein the integrated access and backhaul node uses transmissions from at least one integrated access and backhaul child node to the user equipment via a plurality of backhaul links in a dual connection, wherein the integrated access and backhaul node is a parent node of the at least one integrated access and backhaul child node.

19. The method according to claim 15, wherein:

adding, by the integrated access and backhaul donor distributed element node, a replication indication associated with the data further comprises: including in the backhaul adaptation protocol header a duplication indication for packets related to the traffic flow to be duplicated; and is also provided with

The method comprises the following steps: the integrated access and backhaul donor distributed element node indicates the integrated access and backhaul node that should perform replication of the data.

20. The method of claim 19, wherein the integrated access and backhaul node indicating that copying of the data should be performed is performed by including an address of the integrated access and backhaul node in the backhaul adaptation protocol header.

21. The method of claim 19, wherein the integrated access and backhaul node indicating that copying of the data should be performed is performed by adding a path identification and a backhaul adaptation protocol address to the data, the path identification indicating that the packet should be copied, and the backhaul adaptation protocol address indicating an address of the integrated access and backhaul node for performing the copying.

22. A method, comprising:

determining that a traffic flow of a user equipment is to be replicated by an integrated access and backhaul network node in the network; and

23. The method of claim 22, wherein the integrated access and backhaul network node is an integrated access and backhaul donor distributed element node, and wherein the information comprises at least one of the following information for traffic flows in the downlink direction:

an internet protocol address;

differentiated service code point values;

a stream label;

a field of an internet protocol header; or (b)

Tunnel endpoint identifiers.

24. The method of claim 23, wherein the information that traffic flows of the user equipment in an uplink direction are to be combined further indicates to the integrated access and backhaul donor distributed element node: the plurality of traffic flows of the user equipment in the uplink direction are to be combined into a single traffic flow, and wherein the information comprises: at least one of the following information of the traffic flow in the uplink direction:

Backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

25. The method according to claim 22, wherein:

the information that the traffic flow of the user equipment in the downlink direction is to be replicated comprises: at least one of the following information of the traffic flow in the downlink direction:

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

Any field of the backhaul adaptation protocol header; and

the information that the traffic flows of the user equipment in the uplink direction are to be combined comprises: at least one of the following information of the traffic flow in the uplink direction:

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

26. A computer program comprising code for performing the method according to any of claims 1 to 25 when the computer program is run on a computer.

27. The computer program according to claim 26, wherein the computer program is a computer program product comprising a computer readable medium bearing computer program code embodied therein for use with the computer.

28. The computer program according to claim 26, wherein the computer program is directly loadable into an internal memory of the computer.

29. An apparatus comprising means for:

30. The apparatus of claim 29, wherein:

31. The apparatus of claim 29, wherein:

32. The apparatus of claim 29, wherein:

Said receiving second data from said user equipment over a plurality of uplink traffic flows further comprises: the second data is received from respective ones of the child nodes via the second backhaul link.

33. The apparatus of any one of claims 29 to 32, wherein:

34. The apparatus of any of claims 29 to 33, further comprising: means for determining that the first data is indicated to be replicated in the downlink direction or the second data is indicated to be consolidated based on at least one of:

A replication indication;

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

35. The apparatus of any of claims 29 to 34, further comprising: means for receiving a configuration from an integrated access and backhaul donor node for identifying duplication or merging, the configuration comprising one or more of:

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

36. The apparatus of claim 29, wherein the determining that the second data is indicated as data to be combined comprises: a backhaul adaptation protocol header of the second data is checked to determine whether at least one of a tunnel endpoint identifier or a packet data convergence protocol sequence number indicates that the second data should be merged or whether at least one of a stream control transmission protocol stream identifier or a stream sequence number indicates that the second data should be merged.

37. The apparatus of any of claims 29 to 36, wherein the integrated access and backhaul network node is an integrated access and backhaul node.

38. The apparatus of any of claims 29 to 36, wherein the integrated access and backhaul network node is an integrated access and backhaul donor distributed element node.

39. An apparatus comprising means for:

40. The apparatus of claim 39, wherein determining, by the integrated access and backhaul donor distributed element node, that the data is associated with a data radio bearer to be replicated comprises: configuration information is received from an integrated access and backhaul central unit node for a particular traffic stream to be replicated for the user equipment, and the data is part of the particular traffic stream.

41. The apparatus of claim 40, wherein the configuration information comprises: indicating that the particular traffic flow is to be replicated for the particular internet protocol header content of the user device.

42. The apparatus of any of claims 39 to 40, wherein the replication indication comprises: a duplicate indication in the backhaul adaptation protocol header for the packet associated with the particular traffic flow.

43. The apparatus of any of claims 39 to 42, wherein the integrated access and backhaul node is an access node for the user equipment, the access node using transmissions to the user equipment via a plurality of wireless links in carrier aggregation.

44. The apparatus of claim 43, wherein adding, by the integrated access and backhaul donor distributed element node, a replication indication associated with the data further comprises: a duplication indication for packets related to the traffic flow to be duplicated is included in the backhaul adaptation protocol header.

45. The apparatus of claim 44, wherein the duplicate indications in the backhaul adaptation protocol header comprise: information about the number of copies needed, and/or which access logical channels should be used for packet delivery to the user equipment.

46. The apparatus of any of claims 39-42, wherein the integrated access and backhaul node uses transmissions from at least one integrated access and backhaul child node to the user equipment via a plurality of backhaul links in a dual connection, wherein the integrated access and backhaul node is a parent node of the at least one integrated access and backhaul child node.

47. The apparatus of claim 43, wherein:

The integrated access and backhaul donor distributed element node comprises: means for indicating the integrated access and backhaul node that should perform replication of the data.

48. The apparatus of claim 48, wherein the integrated access and backhaul node indicating that copying of the data should be performed is performed by including an address of the integrated access and backhaul node in the backhaul adaptation protocol header.

49. The apparatus of claim 48, wherein the integrated access and backhaul node that indicates that replication of the data should be performed is performed by adding a path identification and a backhaul adaptation protocol address to the data, the path identification indicating that the packet should be replicated, and the backhaul adaptation protocol address indicating an address of the integrated access and backhaul node that is used to perform the replication.

50. An apparatus comprising means for:

51. The apparatus of claim 50, wherein the integrated access and backhaul network node is an integrated access and backhaul donor distributed element node, and wherein the information comprises at least one of the following information for traffic flows in the downlink direction:

an internet protocol address;

differentiated service code point values;

a stream label;

a field of an internet protocol header; or (b)

Tunnel endpoint identifiers.

52. The apparatus of claim 51, wherein the information that traffic flows of the user equipment in an uplink direction are to be combined further indicates to the integrated access and backhaul donor distributed element node: the plurality of traffic flows of the user equipment in the uplink direction are to be combined into a single traffic flow, and wherein the information comprises: at least one of the following information of the traffic flow in the uplink direction:

Backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

53. The apparatus of claim 50, wherein:

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

Any field of the backhaul adaptation protocol header; and

backhaul radio link control channel identity;

a route identification;

a tunnel endpoint identifier; or (b)

The backhaul adapts any fields of the protocol header.

54. The apparatus of any one of claims 29 to 53, wherein the means comprises:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the execution of the apparatus.

55. An apparatus, comprising:

one or more processors; and

one or more memories, including computer program code,

wherein the one or more memories and the computer program code are configured to, with the one or more processors, cause the apparatus to perform operations comprising:

56. An apparatus, comprising:

one or more processors; and

one or more memories, including computer program code,

57. An apparatus, comprising:

one or more processors; and

one or more memories, including computer program code,