BACKGROUND Field of Disclosure

The present disclosure relates to infrastructure equipment and methods of operating such infrastructure equipment for the more efficient communication of data in a wireless communications network.

The present application claims the Paris Convention priority from European Patent Application number EP22174442.8, filed on 19 May 2022, the contents of which are hereby incorporated by reference.

Description of Related Art

The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.

Latest generation mobile telecommunication systems, such as those based on the 3GPP defined UMTS and Long Term Evolution (LTE) architecture, are able to support a wider range of services than simple voice and messaging services offered by previous generations of mobile telecommunication systems. For example, with the improved radio interface and enhanced data rates provided by LTE systems, a user is able to enjoy high data rate applications such as mobile video streaming and mobile video conferencing that would previously only have been available via a fixed line data connection. The demand to deploy such networks is therefore strong and the coverage area of these networks, i.e. geographic locations where access to the networks is possible, is expected to continue to increase rapidly.

Future wireless communications networks will be expected to routinely and efficiently support communications with an ever-increasing range of devices associated with a wider range of data traffic profiles and types than existing systems are optimised to support. For example, it is expected future wireless communications networks will be expected to efficiently support communications with devices including reduced complexity devices, machine type communication (MTC) devices, high resolution video displays, virtual reality headsets and so on. Some of these different types of devices may be deployed in very large numbers, for example low complexity devices for supporting the “The Internet of Things”, and may typically be associated with the transmissions of relatively small amounts of data with relatively high latency tolerance. Other types of device, for example supporting high-definition video streaming, may be associated with transmissions of relatively large amounts of data with relatively low latency tolerance. Other types of device, for example used for autonomous vehicle communications and for other critical applications, may be characterised by data that should be transmitted through the network with low latency and high reliability. A single device type might also be associated with different traffic profiles / characteristics depending on the application(s) it is running. For example, different consideration may apply for efficiently supporting data exchange with a smartphone when it is running a video streaming application (high downlink data) as compared to when it is running an Internet browsing application (sporadic uplink and downlink data) or being used for voice communications by an emergency responder in an emergency scenario (data subject to stringent reliability and latency requirements).

In view of this there is expected to be a desire for future wireless communications networks, for example those which may be referred to as 5G or new radio (NR) systems / new radio access technology (RAT) systems, as well as future iterations / releases of existing systems, to efficiently support connectivity for a wide range of devices associated with different applications and different characteristic data traffic profiles and requirements.

As radio technologies continue to improve, for example with the development of 5G, the possibility arises for these technologies to be used not only by infrastructure equipment to provide service to wireless communications devices in a cell, but also for interconnecting infrastructure equipment to provide a wireless backhaul so as to communicate between each other. In view of this, there is a need to ensure that links between various infrastructure equipment in the backhaul, as well as the connection to the network of the wireless communications devices these infrastructure equipment serve, are both stable and reliable, particularly where an infrastructure equipment connected to the core network through another of the infrastructure equipment moves away from this infrastructure equipment, or otherwise requires a different connection to the core network.

SUMMARY OF THE DISCLOSURE

The present disclosure can help address or mitigate at least some of the issues discussed above.

Embodiments of the present technique can provide a method of operating a first infrastructure equipment forming a first cell and forming part of a wireless communications network comprising a plurality of other infrastructure equipment each forming a cell. The first infrastructure equipment comprises one or both of a base station part and a mobile terminal part. The method comprises moving from a first geographical location to a second geographical location, wherein an identifier of the first cell is the same as an identifier of a second cell formed by one of the other infrastructure equipment which neighbours the first infrastructure equipment when the first infrastructure equipment is located at the second geographical location, transmitting, to a node of the wireless communications network, a signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell, and receiving, from the node of the wireless communications network, an indication of a new identifier that has been allocated to the first cell, the new identifier being different to the identifier of the second cell.

Embodiments of the present technique, which, in addition to methods of operating infrastructure equipment, relate to infrastructure equipment, circuitry for such infrastructure equipment, wireless communications systems, computer programs, and non-transitory computer-readable storage mediums, allow for the more efficient communication of data in a wireless communications network.

Respective aspects and features of the present disclosure are defined in the appended claims.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the present technology. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein like reference numerals designate identical or corresponding parts throughout the several views, and wherein:

Figure 1 schematically represents some aspects of an LTE-type wireless telecommunication system which may be configured to operate in accordance with certain embodiments of the present disclosure; Figure 2 schematically represents some aspects of a new radio access technology (RAT) wireless telecommunications system which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 3 is a schematic block diagram of an example infrastructure equipment and communications device which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 4 schematically represents some aspects of an example wireless telecommunication network which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 5 is reproduced from [3], and provides a first example of an Integrated Access and Backhaul (IAB) deployment scenario;

Figure 6A is reproduced from [5], and provides a second example of an IAB deployment scenario in which there are multiple candidate routes each comprising multiple hops from the end node to the donor node;

Figure 6B is an extended version of Figure 6A, providing a third example of an IAB deployment scenario in which there are multiple candidate routes each comprising multiple hops from the end node to the donor node;

Figure 7 is a block diagram illustrating a first possible network architecture for providing a wireless backhaul by means of IAB in a wireless telecommunication network which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 8 is a block diagram illustrating a second possible network architecture for providing a wireless backhaul by means of IAB in a wireless telecommunication network which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 9 is a block diagram illustrating a third possible network architecture for providing a wireless backhaul by means of IAB in a wireless telecommunication network which may be configured to operate in accordance with certain embodiments of the present disclosure;

Figure 10 shows an example of an IAB communications system in accordance with embodiments of the present technique; and

Figure 11 shows a flow diagram illustrating a second example process of communications in a communications system in accordance with embodiments of the present technique.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Long Term Evolution Advanced Radio Access Technology (4G)

Figure 1 provides a schematic diagram illustrating some basic functionality of a mobile telecommunications network / system 6 operating generally in accordance with LTE principles, but which may also support other radio access technologies, and which may be adapted to implement embodiments of the disclosure as described herein. Various elements of Figure 1 and certain aspects of their respective modes of operation are well-known and defined in the relevant standards administered by the 3GPP (RTM) body, and also described in many books on the subject, for example, Holma H. and Toskala A [1], It will be appreciated that operational aspects of the telecommunications networks discussed herein which are not specifically described (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be implemented in accordance with any known techniques, for example according to the relevant standards and known proposed modifications and additions to the relevant standards.

The network 6 includes a plurality of base stations 1 connected to a core network 2. Each base station provides a coverage area 3 (i.e. a cell) within which data can be communicated to and from communications devices 4. Although each base station 1 is shown in Figure 1 as a single entity, the skilled person will appreciate that some of the functions of the base station may be carried out by disparate, inter-connected elements, such as antennas (or antennae), remote radio heads, amplifiers, etc. Collectively, one or more base stations may form a radio access network.

Data is transmitted from base stations 1 to communications devices 4 within their respective coverage areas 3 via a radio downlink (DL. Data is transmitted from communications devices 4 to the base stations

1 via a radio uplink (UL). The core network 2 routes data to and from the communications devices 4 via the respective base stations 1 and provides functions such as authentication, mobility management, charging and so on. Terminal devices may also be referred to as mobile stations, user equipment (UE), user terminal, mobile radio, communications device, and so forth. Services provided by the core network

2 may include connectivity to the internet or to external telephony services. The core network 2 may further track the location of the communications devices 4 so that it can efficiently contact (i.e. page) the communications devices 4 for transmitting downlink data towards the communications devices 4.

Base stations, which are an example of network infrastructure equipment, may also be referred to as transceiver stations, nodeBs, e-nodeBs, eNB, g-nodeBs, gNB and so forth. In this regard different terminology is often associated with different generations of wireless telecommunications systems for elements providing broadly comparable functionality. However, certain embodiments of the disclosure may be equally implemented in different generations of wireless telecommunications systems, and for simplicity certain terminology may be used regardless of the underlying network architecture. That is to say, the use of a specific term in relation to certain example implementations is not intended to indicate these implementations are limited to a certain generation of network that may be most associated with that particular terminology.

New Radio Access Technology (5G)

3GPP has completed the basic version of 5G in Rel-15, known as the New Radio Access Technology (NR). In addition, enhancements have been made in Rel-16, incorporating new features such as the 2- step RACH procedure [2], Industrial Internet of Things (IIoT) [3] and NR-based Access to Unlicensed Spectrum (NR-U) [4] .

The NR radio access system employs Orthogonal Frequency Division Multiple Access (OFDMA), where different users are scheduled in different subsets of sub-carriers simultaneously. However, OFDMA requires tight synchronisation in the uplink transmissions in order to achieve orthogonality of transmissions from different users. In essence, the uplink transmissions from all users must arrive at the same time (i.e. they must be synchronised) at the gNB receiver. A UE that is far from the gNB must therefore transmit earlier than a UE closer to the gNB, due to different RF propagation delays. In NR, timing advance commands are applied to control the uplink transmission timing for individual UEs, mainly for Physical Uplink Shared Channels (PUSCHs), Physical Uplink Control Channels (PUCCHs) and Sounding Reference Signals (SRS). The timing advance usually comprises twice the one-way propagation delay between the UE and gNB, thus representing both downlink and uplink delays.

An example configuration of a wireless communications network which uses some of the terminology proposed for and used in NR and 5G is shown in Figure 2. In Figure 2 a plurality of transmission and reception points (TRPs) 10 are connected to distributed control units (DUs) 41, 42 by a connection interface represented as a line 16. Each of the TRPs 10 is arranged to transmit and receive signals via a wireless access interface (i.e. a radio interface for wireless access) within a radio frequency bandwidth available to the wireless communications network. Thus, within a range for performing radio communications via the wireless access interface, each of the TRPs 10, forms a cell of the wireless communications network as represented by a circle 12. As such, wireless communications devices 14 which are within a radio communications range provided by the cells 12 can transmit and receive signals to and from the TRPs 10 via the wireless access interface. Each of the distributed units 41, 42 are connected to a central unit (CU) 40 (which may be referred to as a controlling node) via an interface 46. The central unit 40 is then connected to the core network 20 which may contain all other functions required to transmit data for communicating to and from the wireless communications devices and the core network 20 may be connected to other networks 30.

The elements of the wireless access network shown in Figure 2 may operate in a similar way to corresponding elements of an LTE network as described with regard to the example of Figure 1. It will be appreciated that operational aspects of the telecommunications network represented in Figure 2, and of other networks discussed herein in accordance with embodiments of the disclosure, which are not specifically described (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be implemented in accordance with any known techniques, for example according to currently used approaches for implementing such operational aspects of wireless telecommunications systems, e.g. in accordance with the relevant standards.

The TRPs 10 of Figure 2 may in part have a corresponding functionality to a base station or eNodeB of an LTE network. Similarly, the communications devices 14 may have a functionality corresponding to the UE devices 4 known for operation with an LTE network. It will be appreciated therefore that operational aspects of a new RAT network (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be different to those known from LTE or other known mobile telecommunications standards. However, it will also be appreciated that each of the core network component, base stations and communications devices of a new RAT network will be functionally similar to, respectively, the core network component, base stations and communications devices of an LTE wireless communications network.

In terms of broad top-level functionality, the core network 20 connected to the new RAT telecommunications system represented in Figure 2 may be broadly considered to correspond with the core network 2 represented in Figure 1, and the respective central units 40 and their associated distributed units / TRPs 10 may be broadly considered to provide functionality corresponding to the base stations 1 of Figure 1. The term network infrastructure equipment / access node may be used to encompass these elements and more conventional base station type elements of wireless telecommunications systems. Depending on the application at hand the responsibility for scheduling transmissions which are scheduled on the radio interface between the respective distributed units and the communications devices may lie with the controlling node / central unit and / or the distributed units / TRPs. A communications device 14 is represented in Figure 2 within the coverage area of the first communication cell 12. This communications device 14 may thus exchange signalling with the first central unit 40 in the first communication cell 12 via one of the distributed units / TRPs 10 associated with the first communication cell 12.

It will further be appreciated that Figure 2 represents merely one example of a proposed architecture for a new RAT based telecommunications system in which approaches in accordance with the principles described herein may be adopted, and the functionality disclosed herein may also be applied in respect of wireless telecommunications systems having different architectures.

Thus, certain embodiments of the disclosure as discussed herein may be implemented in wireless telecommunication systems / networks according to various different architectures, such as the example architectures shown in Figures 1 and 2. It will thus be appreciated the specific wireless telecommunications architecture in any given implementation is not of primary significance to the principles described herein. In this regard, certain embodiments of the disclosure may be described generally in the context of communications between network infrastructure equipment / access nodes and a communications device, wherein the specific nature of the network infrastructure equipment / access node and the communications device will depend on the network infrastructure for the implementation at hand. For example, in some scenarios the network infrastructure equipment / access node may comprise a base station, such as an LTE-type base station 1 as shown in Figure 1 which is adapted to provide functionality in accordance with the principles described herein, and in other examples the network infrastructure equipment may comprise a control unit / controlling node 40 and / or a TRP 10 of the kind shown in Figure 2 which is adapted to provide functionality in accordance with the principles described herein.

A more detailed diagram of some of the components of the network shown in Figure 2 is provided by Figure 3. In Figure 3, a TRP 10 as shown in Figure 2 comprises, as a simplified representation, a wireless transmitter 30, a wireless receiver 32 and a controller or controlling processor 34 which may operate to control the transmitter 30 and the wireless receiver 32 to transmit and receive radio signals to one or more UEs 14 within a cell 12 formed by the TRP 10. As shown in Figure 3, an example UE 14 is shown to include a corresponding transmitter 45, a receiver 48 and a controller 44 which is configured to control the transmitter 45 and the receiver 48 to transmit signals representing uplink (UL) data to the wireless communications network via the wireless access interface formed by the TRP 10 and to receive downlink (DL) data as signals transmitted by the transmitter 30 and received by the receiver 48 in accordance with the conventional operation.

The transmitters 30, 45 and the receivers 32, 48 (as well as other transmitters, receivers and transceivers described in relation to examples and embodiments of the present disclosure) may include radio frequency filters and amplifiers as well as signal processing components and devices in order to transmit and receive radio signals in accordance for example with the 5G/NR standard. The controllers 34, 44 (as well as other controllers described in relation to examples and embodiments of the present disclosure) may be, for example, a microprocessor, a CPU, or a dedicated chipset, etc., configured to carry out instructions which are stored on a computer readable medium, such as a non-volatile memory. The processing steps described herein may be carried out by, for example, a microprocessor in conjunction with a random access memory, operating according to instructions stored on a computer readable medium. The transmitters, the receivers and the controllers are schematically shown in Figure 3 as separate elements for ease of representation. However, it will be appreciated that the functionality of these elements can be provided in various different ways, for example using one or more suitably programmed programmable computer(s), or one or more suitably configured application-specific integrated circuit(s) / circuitry / chip(s) / chipset(s). As will be appreciated the infrastructure equipment / TRP / base station as well as the UE / communications device will in general comprise various other elements associated with its operating functionality.

As shown in Figure 3, the TRP 10 also includes a network interface 47 which connects to the DU 42 via a physical interface 16. The network interface 47 therefore provides a communication link for data and signalling traffic from the TRP 10 via the DU 42 and the CU 40 to the core network 20.

The interface 46 between the DU 42 and the CU 40 is known as the F 1 interface which can be a physical or a logical interface. The Fl interface 46 between CU and DU may operate in accordance with specifications 3GPP TS 38.470 and 3GPP TS 38.473, and may be formed from a fibre optic or other wired or wireless high bandwidth connection. In one example the connection 16 from the TRP 10 to the DU 42 is via fibre optic. The connection between a TRP 10 and the core network 20 can be generally referred to as a backhaul, which comprises the interface 16 from the network interface 47 of the TRP 10 to the DU 42 and the Fl interface 46 from the DU 42 to the CU 40. Example arrangements of the present technique can be formed from a wireless communications network corresponding to that shown in Figures 1 or 2, as shown in Figure 4. Figure 4 provides an example in which cells of a wireless communications network are formed from infrastructure equipment which are provided with an Integrated Access and Backhaul (IAB) capability. The wireless communications network 100 comprises the core network 20 and a first, a second, a third and a fourth communications device (respectively 101, 102, 103 and 104) which may broadly correspond to the communications devices 4, 14 described above.

The wireless communications network 100 comprises a radio access network, comprising a first infrastructure equipment 110, a second infrastructure equipment 111, a third infrastructure equipment 112, and a fourth infrastructure equipment 113. Each of the infrastructure equipment provides a coverage area (i.e. a cell, not shown in Figure 4) within which data can be communicated to and from the communications devices 101 to 104. For example, the fourth infrastructure equipment 113 provides a cell in which the third and fourth communications devices 103 and 104 may obtain service. Data is transmitted from the fourth infrastructure equipment 113 to the fourth communications device 104 within its respective coverage area (not shown) via a radio downlink. Data is transmitted from the fourth communications device 104 to the fourth infrastructure equipment 113 via a radio uplink.

The infrastructure equipment 110 to 113 in Figure 4 may correspond broadly to the TRPs 10 of Figure 2 and Figure 3.

The first infrastructure equipment 110 in Figure 4 is connected to the core network 20 by means of one or a series of physical connections. The first infrastructure equipment 110 may comprise the TRP 10 (having the physical connection 16 to the DU 42) in combination with the DU 42 (having a physical connection to the CU 40 by means of the Fl interface 46) and the CU 40 (being connected by means of a physical connection to the core network 20).

However, there is no direct physical connection between any of the second infrastructure equipment 111, the third infrastructure equipment 112, and the fourth infrastructure equipment 113 and the core network 20. As such, it may be necessary (or, otherwise determined to be appropriate) for data received from a communications device (i.e. uplink data), or data for transmission to a communications device (i.e. downlink data) to be transmitted to or from the core network 20 via other infrastructure equipment (such as the first infrastructure equipment 110) which has a physical connection to the core network 20, even if the communications device is not currently served by the first infrastructure equipment 110 but is, for example, in the case of the wireless communications device 104, served by the fourth infrastructure equipment 113.

The second, third and fourth infrastructure equipment 111 to 113 in Figure 4 may each comprise a TRP, broadly similar in functionality to the TRPs 10 of Figure 2.

In some arrangements of the present technique, one or more of the second to fourth infrastructure equipment 111 to 113 in Figure 4 may further comprise a DU 42, and in some arrangements of the present technique, one or more of the second to fourth infrastructure equipment 110 to 113 may comprise a DU and a CU.

In some arrangements of the present technique, the CU 40 associated with the first infrastructure equipment 110 may perform the function of a CU not only in respect of the first infrastructure equipment 110, but also in respect of one or more of the second, the third and the fourth infrastructure equipment l l l to 113.

In order to provide the transmission of the uplink data or the downlink data between a communications device and the core network, a route is determined by any suitable means, with one end of the route being an infrastructure equipment physically connected to a core network and by which uplink and downlink traffic is routed to or from the core network.

In the following, the term ‘node’ is used to refer to an entity or infrastructure equipment which forms a part of a route for the transmission of the uplink data or the downlink data.

An infrastructure equipment which is physically connected to the core network and operated in accordance with an example arrangement may provide communications resources to other infrastructure equipment and so is referred to as a ‘donor node’. An infrastructure equipment which acts as an intermediate node (i.e. one which forms a part of the route but is not acting as a donor node) is referred to as a ‘relay node’. It should be noted that although such intermediate node infrastructure equipment act as relay nodes on the backhaul link, they may also provide service to communications devices. The relay node at the end of the route which is the infrastructure equipment controlling the cell in which the communications device is obtaining service is referred to as an ‘end node’.

In the wireless network illustrated in Figure 4, each of the first to fourth infrastructure equipment 110 to 113 may therefore function as nodes. For example, a route for the transmission of uplink data from the fourth communications device 104 may consist of the fourth infrastructure equipment 113 (acting as the end node), the third infrastructure equipment 112 (acting as a relay node), and the first infrastructure equipment 110 (acting as the donor node). The first infrastructure 110, being connected to the core network 20, transmits the uplink data to the core network 20.

For clarity and conciseness in the following description, the first infrastructure equipment 110 is referred to below as the ‘donor node’, the second infrastructure equipment 111 is referred to below as ‘Node 1 ’, the third infrastructure equipment 112 is referred to below as ‘Node 2’ and the fourth infrastructure equipment 113 is referred to below as ‘Node 3’.

For the purposes of the present disclosure, the term ‘upstream node’ is used to refer to a node acting as a relay node or a donor node in a route, which is a next hop when used for the transmission of data via that route from a wireless communications device to a core network. Similarly, ‘downstream node’ is used to refer to a relay node from which uplink data is received for transmission to a core network. For example, if uplink data is transmitted via a route comprising (in order) the Node 3 113, the Node 1 111 and the donor node 110, then the donor node 110 is an upstream node with respect to the Node 1 111, and the Node 3 113 is a downstream node with respect to the Node 1 111.

More than one route may be used for the transmission of the uplink/downlink data from/to a given communications device; this is referred to herein as ‘multi-connectivity’. For example, the uplink data transmitted by the wireless communications device 104 may be transmitted either via the Node 3 113 and the Node 2 112 to the donor node 110, or via the Node 3 113 and the Node 1 111 to the donor node 110.

In the following description, example arrangements are described in which each of the nodes is an infrastructure equipment; the present disclosure is not so limited. A node may comprise at least a transmitter, a receiver and a controller. In some arrangements of the present technique, the functionality of a node (other than the donor node) may be carried out by a communications device, which may be the communications device 4 (of Figure 1) or 14 (of Figure 2), adapted accordingly. As such, in some arrangements of the present technique, a route may comprise one or more communications devices. In other arrangements, a route may consist of only a plurality of infrastructure equipment.

In some arrangements of the present technique, an infrastructure equipment acting as a node may not provide a wireless access interface for the transmission of data to or by a communications device other than as part of an intermediate transmission along a route.

In some arrangements of the present technique, a route is defined considering a wireless communications device (such as the wireless communications device 104) as the start of a route. In other arrangements a route is considered to start at an infrastructure equipment which provides a wireless access interface for the transmission of the uplink data by a wireless communications device.

Each of the first infrastructure equipment acting as the donor node 110 and the second to fourth infrastructure equipment acting as the Nodes 1 to 3 111, 112, 113 may communicate with one or more other nodes by means of an inter-node wireless communications link, which may also be referred to as a wireless backhaul communications links. For example, Figure 4 illustrates four inter-node wireless communications links 130, 132, 134, 136.

Each of the inter-node wireless communications links 130, 132, 134, 136 may be provided by means of a respective wireless access interface. Alternatively, two or more of the inter-node wireless communications links 130, 132, 134, 136 may be provided by means of a common wireless access interface and in particular, in some arrangements of the present technique, all of the inter-node wireless communications links 130, 132, 134, 136 are provided by a shared wireless access interface.

A wireless access interface which provides an inter-node wireless communications link may also be used for communications between an infrastructure equipment (which may be a node) and a communications device which is served by the infrastructure equipment. For example, the fourth wireless communications device 104 may communicate with the infrastructure equipment Node 3 113 using the wireless access interface which provides the inter-node wireless communications link 134 connecting the Node 3 113 and the Node 2 112.

The wireless access interface(s) providing the inter-node wireless communications links 130, 132, 134, 136 may operate according to any appropriate specifications and techniques. In some arrangements of the present technique, a wireless access interface used for the transmission of data from one node to another uses a first technique and a wireless access interface used for the transmission of data between an infrastructure equipment acting as a node and a communications device may use a second technique different from the first. In some arrangements of the present technique, the wireless access interface(s) used for the transmission of data from one node to another and the wireless access interface(s) used for the transmission of data between an infrastructure equipment and a communications device use the same technique.

Examples of wireless access interface standards include the third generation partnership project (3GPP)- specified GPRS/EDGE (“2G”), WCDMA (UMTS) and related standards such as HSPA and HSPA+ (“3G”), LTE and related standards including LTE-A (“4G”), and NR (“5G”). Techniques that may be used to provide a wireless access interface include one or more of TDMA, FDMA, OFDMA, SC-FDMA, CDMA. Duplexing (i.e. the transmission over a wireless link in two directions) may be by means of frequency division duplexing (FDD) or time division duplexing (TDD) or a combination of both. In some arrangements of the present technique, two or more of the inter-node wireless communications links 130, 132, 134, 136 may share communications resources. This may be because two or more of the inter-node wireless communications links 130, 132, 134, 136 are provided by means of a single wireless access interface or because two or more of the inter-node wireless communications links 130, 132, 134, 136 nevertheless operate simultaneously using a common range of frequencies.

The nature of the inter-node wireless communications links 130, 132, 134, 136 may depend on the architecture by which the wireless backhaul functionality is achieved.

Integrated Access and Backhaul (IAB) for NR

One area of NR under development is Integrated Access and Backhaul (IAB). Several requirements and aspects for the integrated access and wireless backhaul for NR to address are discussed in [5], which include:

• Efficient and flexible operation for both inband and outband relaying in indoor and outdoor scenarios;

• Multi-hop and redundant connectivity;

• End-to-end route selection and optimisation;

• Support of backhaul links with high spectral efficiency;

• Support of legacy NR UEs .

The stated objective of the study detailed in [5] is to identify and evaluate potential solutions for topology management for single-hop/multi-hop and redundant connectivity, route selection and optimisation, dynamic resource allocation between the backhaul and access links, and achieving high spectral efficiency while also supporting reliable transmission.

Figure 5 shows the scenario presented in [5], where a backhaul link is provided from cell site A 501 to cells B 502 and C 504 over the air. It is assumed that cells B 502 and C 504 have no wired backhaul connectivity. Considering the CU/DU split architecture in NR as described above, it can be assumed that all of cells A 501, B 502 and C 504 have a dedicated DU unit and are controlled by the same CU.

Several architecture requirements for IAB are laid out in [6], These include the support for multiple backhaul hops, that topology adaptation for physically fixed relays shall be supported to enable robust operation, minimisation of impact to core network specifications, consideration of impact to core networking signalling load, and Release 15 NR specifications should be reused as much as possible in the design of the backhaul link, with enhancements considered.

Figure 6A is reproduced from [7], and shows an example of a wireless communications system comprising a plurality of lAB-enabled nodes, which may for example be TRPs forming part of an NR network. These comprise an IAB donor node 601 which has a connection to the core network, two IAB nodes (a first IAB node 602 and a second IAB node 604) which have backhaul connections to the IAB donor node 601, and a third IAB node 606 (or end IAB node) which has a backhaul connection to each of the first IAB node 602 and the second IAB node 604. Each of the first IAB node 601 and third IAB node 606 has wireless access connections to UEs 608 and 610 respectively. As shown in Figure 6A, originally the third IAB node 606 may communicate with the IAB donor node 601 via the first IAB node 602. After the second IAB node 604 emerges, there are now two candidate routes from the third IAB node 606 to the IAB donor node 601 ; via the first IAB node 602 and via the new second IAB node 604. The new candidate route via the second IAB node 604 will play an important role when there is a blockage in the first IAB node 602 to IAB donor node 604 links. Hence, knowing how to manage the candidate routes efficiently and effectively is important to ensure timely data transmission between relay nodes, especially when considering the characteristics of wireless links.

In the case that the link between the first IAB node 602 and the third IAB node 606 is deteriorating, or the first IAB node 602 becomes overloaded, one of the nodes in the system (this could be the donor node 601 or the first IAB node 602 itself) will need to make a decision to change the route from the third IAB node 606 to the IAB donor node 601 from that via the first IAB node 602 to that via the second IAB node 604.

In Figure 6A, only the IAB Donor gNB 601 has a fixed line backhaul into the core network. It should be assumed in this case that the traffic from all the UEs 610 within the third IAB node’s 606 coverage is backhauled firstly to the first IAB node 602. This backhaul link must compete for capacity on the component carrier serving the first IAB Node 602 with all the UEs 608 within the coverage area of the first IAB Node 602. In the relevant art, the first IAB Node 602 in such a system as that of Figure 6A is called a “hop” - it relays communications between the end (third) IAB node 606 and the donor IAB node 601. The backhaul link to the first IAB Node 602 requires enough capacity to support the traffic from all the UEs 610, bearing in mind that some of these may have stringent quality of service (QoS) requirements that translate into high traffic intensities.

Figure 6B is an extended version of Figure 6A, and shows what happens when there are multiple layers of IAB nodes in the deployment scenario. In the example of Figure 6A, the third IAB node 606 is the child node of the first IAB node 602, and the first IAB node 602 may be the parent node of the third IAB node 606. However, a parent node may not necessarily be the next node up (i.e. one hop in the uplink direction) towards the IAB donor node 601. A parent node may be more than one hop away from its child node or children nodes, and is in a general sense configured to allocate uplink communications resources to the child node. For example, the donor IAB node 601 may in fact be the parent node of the third IAB node 606. This is shown with greater clarity in Figure 6B.

In Figure 6B, in addition to IAB node 601, 602, 604 and 606 as shown in Figure 6A, there are additional IAB nodes 612 and 614 at the same layer or level of the network as IAB node 606. Below these are IAB nodes 616, 618, 620 and 622, which are now end nodes, in that they have no downlink backhaul connections to other IAB nodes. Here, it could be that the first IAB node 602 is still the parent of the third IAB node 606, but may also be the parent of IAB node 612. Further, the first IAB node 602 may be the parent of IAB nodes 616, 618 and 620 too, or may be a grandparent node to these nodes if nodes 606 and 612 are their parents. Furthermore, some child nodes may have multiple parent nodes, and can select from between them when transmitted uplink data in dependence on certain criteria, such as relative link qualities between the child node and its multiple parent nodes, or a relative load status between the parent nodes, for example.

Various architectures have been proposed in order to provide the IAB functionality. The below described embodiments of the present technique are not restricted to a particular architecture. However, a number of candidate architectures which have been considered in, for example, 3GPP document [8] are described below.

Figure 7 illustrates one possible architecture, sometimes referred to as “Architecture la”, by which the donor Node 110, the Node 1 111 and the Node 3 113 may provide a wireless backhaul to provide connectivity for the UEs 104, 101, 14. In Figure 7, each of the infrastructure equipment acting as an IAB nodes 111, 113 and the donor node 110, includes a distributed unit (DU) 42, 711, 731 which communicates with the UEs 14, 101, 104 and (in the case of the DUs 42, 511 associated with the donor node 110 and the Node 1 111) with the respective downstream IAB nodes 111, 113. Each of the IAB nodes 111, 113 (not including the donor node 110) includes a mobile terminal (MT) 712, 732, which includes a transmitter and receiver (not shown) for transmitting and receiving data to and from the DU of an upstream IAB node and an associated controller (not shown). The inter-node wireless communications links 130, 136 may be in the form of new radio (NR) “Uu” wireless interface. The mobile terminals 712, 732 may have substantially the same functionality as a UE, at least at the access stratum (AS) layer. Notably, however, an MT may not have an associated subscriber identity module (SIM) application; a UE may be conventionally considered to be the combination of an MT and a SIM application.

The Uu wireless interfaces used by IAB nodes to communicate with each other may also be used by UEs to transmit and receive data to and from the DU of the upstream IAB node. For example, the Uu interface 720 which is used by the Node 1 111 for communication with the donor node 110 may also be used by the UE 14 to transmit and receive data to and from the donor node 110.

Similarly, an end node (such as the Node 3 113) may provide a Uu wireless interface 722 for the fourth UE 104 to communicate with the DU 731 of the Node 3 113.

Alternative candidate architectures for the provision of IAB are provided in Figure 8 and Figure 9, sometimes referred to as “Architectures 2a and 2b” respectively. In both Figure 8 and Figure 9, each IAB node includes a gNB function, providing a wireless access interface for the use of downstream IAB nodes and wireless communications devices. It should be appreciated that, although not shown in Figures 8 and 9, the gNB of each IAB donor 110 comprises a CU and a DU.

Figure 9 differs from Figure 7 in that, in Figure 7, PDU sessions are connected end-on-end to form the wireless backhaul; in Figure 9, PDU sessions are encapsulated so that each IAB node may establish an end-to-end PDU session which terminates at the IAB donor node 110.

IAB nodes - and specifically any of relay or end IAB nodes such as Nodes 1 to 3 111, 112, 113 of Figure 4, or IAB nodes 602, 604, 606, 612, 614, 616, 618, 620, and 622 of Figures 6A and 6B - may also be mobile (i.e. movable and not in a fixed location), for example through their mounting or attachment to moving ground-based, water-based, or airborne vehicles or any other type of moving platform which provides cellular coverage and/or capacity enhancement to surrounding UEs or UEs also mounted/attached to or on-board the vehicle/moving platform. Such movement of mobile IAB nodes must be taken into consideration in the overall management of IAB systems, with respect to changes in routes (and IAB handover operations), changes in how UEs are served (including UE handover operations), and considerations as to the placement of such mobile IAB nodes in wireless communications networks comprising or formed by cells operated by IAB nodes. Mobile IAB is addressed in, for example, [9], which discusses justifications and objectives for the support of mobile IAB in NR systems.

The detailed objectives outlined in [9] are that procedures should be defined for migration/topology adaptation to enable IAB -node mobility, enhancements should be made for mobility of an IAB -node together with its served UEs, and mitigation of interference due to lAB-node mobility should be enabled, including the avoidance of reference and control signal collisions. In regard to the development of mobile IAB, [9] stipulates that the principle of mobile IAB nodes being able to serve legacy UEs must be respected, and that any optimisation for mobile IAB may involve Rel 18 UE enhancements, as long as such enhancements are backwards compatible.

With the introduction of mobile IAB within the framework of what is outlined in [9], the present inventors have identified that the above-described objective of interference mitigation due to IAB nodes’ mobility may be caused by Physical Cell Identifier (PCI) collisions, and to a lesser extent, PCI confusion. As those skilled in the art would appreciate, a PCI is an identifier of a specific cell (operated by a base station) at the physical layer, signalled to UEs through a combination of the primary synchronisation signal (PSS) and the secondary synchronisation signal (SSS) by the base station, and is used in encoding and decoding transmissions between the base station and UEs served by the cell. When a cell has the same PCI as a neighbouring cell, UEs served by one of those cells will receive (and attempt to decode) interfering signals transmitted from both cells, and signals transmitted by the UEs will be received by both cells - this is a PCI collision. Where more than one cell which neighbour a particular cell have the same PCI as each other (but different to the particular cell), a UE in that particular cell may not be able to easily determine which neighbouring cell to hand over to if necessary - this is an example of PCI confusion.

Typically, PCIs are allocated by the network from a given set of (a limited number of) PCI values, where the network ensures PCI values are unique among all surrounding cells. In legacy systems where base stations are located in fixed positions, this therefore avoids the problem of PCI collisions. However, in mobile IAB systems, since the IAB nodes move, it is possible that an IAB node which operates a cell with a particular PCI moves to a location where it neighbours (or is close to) another cell with the same PCI, thus causing a PCI collision. More broadly, in any wireless communications systems where base stations move (e.g. through their attachment or mounting to moving vehicles), there is a risk that such a base station may move to a location where its cell’s PCI collides with the PCI of a neighbouring cell.

As described above, each IAB node comprises both an IAB-MT (which is a part which can be essentially treated as a UE) and an IAB-DU (which is a part that can be essentially treated as a base station). Embodiments of the present technique provide solutions to the above-described problem of PCI collisions in wireless communications systems, such as in mobile IAB systems, where lAB-MTs and lAB-DUs may take different roles in such solutions.

PCI Collision Detection and Avoidance in Mobile IAB

Figure 10 shows a part schematic, part message flow diagram representation of an example wireless communications system 1000 comprising a first infrastructure equipment 1001 forming a first cell and forming part of a wireless communications network comprising a plurality of other infrastructure equipment 1002, 1003, 1004, 1005, 1006 each forming a cell in accordance with at least some embodiments of the present technique. The first infrastructure equipment 1001 comprises one or both of a base station part 1001.1 and a mobile terminal part 1001.2, and may be configured to transmit signals to and/or receive signals from one or more others of the plurality of infrastructure equipment 1002, 1003, 1004, 1005, 1006.

Specifically, in accordance with at least some arrangements of embodiments of the present disclosure, the first infrastructure equipment 1001 of the example system 1000 of Figure 10 may be an integrated access and backhaul, IAB, node comprising both of the base station part 1001.1 (which may be a DU or a gNB or the like) and the mobile terminal part 1001.2, where the first infrastructure equipment 1001 is configured to communicate with one or more of the plurality of other infrastructure equipment 1003, 1004, 1005, 1006 (i.e. other relay/end IAB nodes) via a backhaul communications link (e.g. implemented by a Uu interface between the mobile terminal (MT) part of one of the IAB nodes and the distributed unit (DU)/gNB part of another (i.e. an upstream) of the IAB nodes), and with one of the plurality of other infrastructure equipment 1002 acting as an IAB donor node via a backhaul communications link (e.g. implemented by a Fl interface), where the IAB donor node 1002 is communicatively coupled (e.g. by a physical wired link) to a core network part 1007 of the wireless communications network. Each of the first infrastructure equipment 1001 and plurality of other infrastructure equipment 1002, 1003, 1004, 1005, 1006 may comprise a transceiver (or transceiver circuitry), and a controller (or controller circuitry). Each of the controllers may be, for example, a microprocessor, a CPU, or a dedicated chipset, etc. Furthermore, one or more of the first infrastructure equipment 1001 and the plurality of other infrastructure equipment 1002, 1003, 1004, 1005, 1006 may each be configured to serve one or more communications devices (i.e. UEs), which are not shown in Figure 10 for simplicity.

As shown in the example of Figure 10, the transceiver circuitry and the controller circuitry of the first infrastructure equipment 1001 are configured in combination to move 1021 from a first geographical location 1011 to a second geographical location 1012, wherein an identifier of the first cell (e.g. where the identifier may be a physical cell identifier (PCI) which may have a value of 176 as shown in the example of Figure 10) is the same as an identifier of a second cell formed by one of the other infrastructure equipment 1003 which neighbours the first infrastructure equipment 1001 when the first infrastructure equipment 1001 is located at the second geographical location 1012, to transmit 1022, to a node of the wireless communications network 1002 (e.g. a central unit (CU) of the network or an IAB donor node (which may as described above comprise a CU)), a signal which indicates that the identifier of the first cell might be (and which may be confirmed by the core network/node of the network) the same as (and hence collides 1024 with) the identifier of the second cell, and to receive 1023, from the node of the wireless communications network 1002 (e.g. a CU, or an IAB donor node (either directly from the IAB donor node or via one or more hops from other relay IAB nodes between the IAB donor node and the first infrastructure equipment)), an indication of a new identifier that has been allocated to the first cell (which may be indicated, for example, through a combination of PSS and SSS received from the IAB donor node/CU by the mobile terminal part 1001.2 of the first infrastructure equipment 1001), the new identifier being different to the identifier of the second cell (and where the new identifier may have been selected for the first infrastructure equipment 1001 by the core network 1007 or by the CU). Those skilled in the art would also appreciate that in some arrangements of embodiments of the present technique, particularly where the first infrastructure equipment 1001 and plurality of other infrastructure equipment 1002, 1003, 1004, 1005, 1006 are not IAB nodes, the transmitted indication 1022 of the first and second identifiers being the same and the received indication 1023 of the new identifier may each be transmitted/received by the first infrastructure equipment 1001 directly from the core network 1007 or by the CU (which may be a CU within an IAB donor node) or an Operations, Administration, and Maintenance (0AM) entity, the node of the wireless communications network thus being either within or communicatively connected to the core network 1007.

Essentially, embodiments of the present technique propose that, where an infrastructure equipment (which is mobile, e.g. through mounting on/attachment to a moving vehicle) moves to a new location where there is a PCI collision with a neighbouring infrastructure equipment, this PCI collision should be detected (either pre-emptively or upon it happening) and corrected, through the allocation of a new PCI value to the infrastructure equipment which has moved (or indeed to the other infrastructure equipment with which its PCI value has collided). Here, where reference is made to neighbouring cells, such cells comprise both those which directly neighbour the first cell (i.e. are adjacent to or overlap with the first cell, without other cells in between), where the same PCIs thus cause PCI collisions, or neighbours of neighbours (or at least cells within which signals from the first cell may directly - albeit with low reception power - be able to reach), where the same PCIs may cause PCI collisions or PCI confusion. Figure 11 shows a flow diagram illustrating a second example process of communications in a communications system in accordance with embodiments of the present technique. The process shown by Figure 11 is a method of operating a first infrastructure equipment (e.g. a mobile IAB relay or end node) forming a first cell and forming part of a wireless communications network comprising a plurality of other infrastructure equipment (e.g. other mobile IAB relay/end nodes or IAB donor nodes) each forming a cell, the first infrastructure equipment comprising one or both of a base station part and a mobile terminal part.

In some arrangements of embodiments of the present technique, the PCI collision detection may be performed by the network (where here and throughout the present application, “network” is intended to refer to either the CU, which may be a CU in an IAB donor node, to the IAB donor node itself, or to the core network) based on the transmission, by the first infrastructure equipment to the node of the wireless communications network, of a location report indicating a geographical location of the first infrastructure equipment. Here, this location report indicates to the -network (e.g. to the CU/IAB donor node or 0AM) that, when the geographical location of the first infrastructure equipment is the second geographical location (i.e. the first cell either neighbours or is in the vicinity of the second cell), there is - or is likely to be - a PCI collision (or PCI confusion). Such arrangements take the burden of PCI collision detection away from the individual mobile IAB nodes/network relays/base stations and place this on the network (i.e. the core network, CU, or the IAB donor node), since the mobile IAB nodes/network relays/base stations are effectively unaware of any PCI collisions, simply reporting their location to the network based on certain criteria and leaving it to the network to determine when it has moved to a location at which a PCI collision has or may be caused.

The first infrastructure equipment (e.g. mobile IAB node) may transmit the location report to a location management function (LMF) in the core network. The LMF may keep the mapping between locations and PCIs, or may share mobile node locations regularly with the 0AM entity, which then keeps this mapping. Accordingly, either the LMF may instruct 0 AM to change the PCI of the mobile node when a collision is detected, or the 0AM may decide by itself based on the information provided by the LMF. Here, the 0AM may then instruct the mobile node (either via the CU, via the lAB-donor, or via a direct 0AM link between the centralised 0AM entity and the local 0AM entity) that the mobile node is to change its PCI. If the 0AM indicates the new PCI directly using the 0AM link between the centralised 0AM entity and the local 0AM entity, then it is beneficial that the IAB-MT or mobile entity informs the CU of the new PCI. Alternatively, the CU may be informed by the centralised 0AM entity itself. This is beneficial for interference management.

In addition to the report of mobile IAB node location, it might be useful to include the transmission power, the antenna height, grand level, antenna position, frequency in the report. These factors may have some impact on the range of PCI collision risk. Accordingly, in some arrangements of embodiments of the present technique, one or more of such other pieces of information may be indicated either in the location report, in other reports, or in a more general report which itself includes the location report. For example, if the antenna height/position of a mobile IAB node is significantly above ground level, coverage provided by that mobile IAB node at the ground level may be very wide (though the transmission power will be low as this will be dispersed across the wide coverage range), leading to an increased likelihood of a PCI collision (or PCI confusion) being caused.

In arrangements of embodiments of the present disclosure where the first infrastructure equipment may be a mobile IAB node, such a location report may be transmitted to the IAB donor node for example by either of the mobile terminal part of the mobile IAB node or the base station/distributed unit part of the mobile IAB node. Where the location report is transmitted by the mobile terminal part of the first infrastructure equipment, the location report may be transmitted by the mobile terminal part of the first infrastructure equipment to the node of the wireless communications network (e.g. the IAB donor node) using explicit signalling, e.g. via radio resource control (RRC) signalling. This report may be triggered by a number of things, for example:

• The IAB node has moved by a certain distance from where it last reported its location;

• The IAB node has moved to a specific area e.g. downtown;

• The IAB node has not reported its location for a certain time;

• A detection of strong interference at the IAB node; or

• Another mobile (IAB) relay/end node is approaching, which may detected by the mobile IAB node from its system information, for example.

Similarly, where the location report is transmitted by the base station part of the first infrastructure equipment, the location report may be transmitted by the base station part of the first infrastructure equipment to the node of the wireless communications network (e.g. the IAB donor node) using explicit signalling, e.g. via Fl application protocol (F1AP) signalling - i.e. AP signalling via the Fl interface between the mobile IAB end/relay node and the IAB donor node. This report may be triggered, in the same way as the explicitly signalled location report by the mobile terminal part of the mobile IAB node as described above, by a number of things, for example:

• The IAB node has moved by a certain distance from where it last reported its location;

• The IAB node has moved to a specific area e.g. downtown;

• The IAB node has not reported its location for a certain time;

• A detection of strong interference at the IAB node; or

• Another mobile (IAB) relay/end node is approaching, which may detected by the mobile IAB node from its system information, for example.

Hence, in both cases (i.e. where the location report is transmitted by the MT or the BS/DU part of the mobile IAB node), the location report may be transmitted by the first infrastructure equipment based on one of (or indeed any combination of two or more of): the first infrastructure equipment determining that the first infrastructure equipment has moved more than a predetermined threshold distance from a previous geographical location from which the first infrastructure equipment last transmitted a location report, the first infrastructure equipment determining that the first infrastructure equipment has moved into a specific geographical area, the first infrastructure equipment determining that a predetermined time has passed since the first infrastructure equipment last transmitted a location report, the first infrastructure equipment detecting a level of interference exceeding a predefined threshold level, or the first infrastructure equipment determining that a distance between the first infrastructure equipment and at least one of the plurality of other infrastructure equipment is decreasing.

After the network receives this report, it can evaluate whether there are any PCI collisions (or confusion), or whether the mobile IAB node is going to collide (in terms of its PCI) with any other cells if it continues to move in the same direction.

In some arrangements of embodiments of the present technique, the PCI collision (or indeed confusion) detection may be performed by the first infrastructure equipment based on the detection of interference at the first infrastructure equipment, with the detected PCI collision indicated by the first infrastructure equipment to the network. Alternatively, the detected interference may be indicated by the first infrastructure equipment to the network, where here this detected interference indicates to the network that there is - or is likely to be - a PCI collision (or PCI confusion). Of course, the detected interference, even if at a high level, is not necessarily due to a PCI collision - and so the network (i.e. the IAB donor node, the CU, or the core network) performs further measurements and checks on the basis of the received indication of the detected interference, and may determine on the basis of these measurements/checks that there is a PCI collision (or PCI confusion) which is either causing or partly affecting the high level of detected and indicated interference. Such arrangements place more of the burden of PCI collision detection onto he individual mobile IAB nodes/network relays/base stations, though the network is still involved in resolving the issue by allocating new PCIs, and also may detect the PCI collisions based on received indications of detected interference. However, such arrangements - while in some cases less efficient and desirable from an individual mobile IAB node/network relay/base station basis since such nodes are required to continuously perform measurements (and in some cases perform the determination as to whether or not there is or is likely to be a PCI collision) - provide a useful mechanism for PCI collision/confusion detection in cases where individual nodes are not allowed to share their locations with the network, due to privacy issues or the like. Furthermore, such arrangements may not enable the effective pre-emption of PCI collisions, but rather detect them (via increased interference levels) as and when they happen, which might case latency or other issues for UEs. However, such arrangements, as described above, can be applied in more situations than the arrangements which require location report transmission, as they can be applied regardless of whether or not location sharing is allowed.

In arrangements of embodiments of the present disclosure where the first infrastructure equipment is a mobile IAB node, such an indication of either the detected interference and/or that there is a PCI collision may be transmitted to the IAB donor node for example by either of the mobile terminal part of the mobile IAB node or the base station/distributed unit part of the mobile IAB node.

Where the indication of either the detected interference and/or that there is a PCI collision may be transmitted to the IAB donor node by the mobile terminal part of the mobile IAB node, the IAB-MT may for example be configured with interference detection, such as an interference measurement, e.g. event II (a description of which can be found in [10]), by the lAB-donor-CU. Here, the IAB-MT may report to the lAB-donor-CU when this event has been triggered via RRC signalling. In other words, the mobile terminal part of the first infrastructure equipment may be configured by the wireless communications network to perform interference measurements, and wherein the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell (which in some arrangements may amount to the first infrastructure equipment indicating there is a PCI collision, and in other arrangements may amount to the signalling of the detected interference which indicates to the network that investigation of the high level of interference is needed, and where the interference may be determined by the network to be caused by a PCI collision) may be transmitted by the mobile terminal part of the first infrastructure equipment when a level of the detected interference exceeds a predefined threshold level - wherein here the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell may be transmitted by the mobile terminal part of the first infrastructure equipment to the node of the wireless communications network via RRC signalling.

Where the indication of either the detected interference and/or that there is a PCI collision may be transmitted to the IAB donor node by the base station part of the mobile IAB node, the IAB-DU may for example be configured to monitor the interference level by the lAB-donor-CU, and to report the detected interference or the determined PCI collision/confusion via F1AP signalling. In other words, the base station part of the first infrastructure equipment may be configured by the wireless communications network to monitor interference within the first cell, and wherein the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell (which, again, in some arrangements may amount to the first infrastructure equipment indicating there is a PCI collision, and in other arrangements may amount to the signalling of the detected interference which indicates to the network that investigation of the high level of interference is needed, and where the interference may be determined by the network to be caused by a PCI collision) may be transmitted by the base station part of the first infrastructure equipment based on the monitored interference - wherein here wherein the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell may be transmitted by the base station part of the first infrastructure equipment to the node of the wireless communications network via F1AP signalling.

In some arrangements of embodiments of the present technique, this configuration of interference monitoring for the IAB DU may comprise the indication of a “listening mode” in which the IAB-DU is to operate during a pre-defined period (i.e. gap period) where it is configured only to monitor interference, and not to transmit or receive any other signals. In other words, the base station part of the first infrastructure equipment may be configured by the wireless communications network to monitor interference within the first cell during one or more pre-defined gap periods during which the base station part of the first infrastructure equipment does not transmit or receive any signals, and the first infrastructure equipment may be configured to receive, from the node of the wireless communications network, a configuration of the one or more pre-defined gap periods.

As mentioned above, during this gap period, the IAB-DU will therefore stop any transmitting/receiving of data, as well as stopping the scheduling of data transmissions to/from its downstream nodes during this period. The configuration of the one or more predefined gap periods may comprise one or more of:

• At which point within allocated resources e.g. in terms of the positions in time/frequency the measurement gaps are located;

• Uength/duration of the gap periods and/or a length duration of the actual measurements to be performed during the gap periods;

• Periodicity/repetition of the gap periods; and

• Trigger conditions for the starting of the detection of interference during measurement gaps, if any e.g., location of the mobile IAB node (e.g. the location is within a predefined or signalled area or one of a plurality of predefined or signalled areas), interference level detected by the mobile IAB node (e.g. this interference level is at or above a threshold level of interference), etc.

In some arrangements of embodiments of the present technique, the lAB-donor-CU may need to share the gap configuration with which a mobile IAB node is configured with that IAB node’s parent IAB node, in order to avoid the mobile IAB node being scheduled with any data transmissions/receptions by its parent IAB node during the gap period. Such an indication of the gap configuration may be indicated by the donor node itself to the parent node via F1AP signalling, or as an alternative, the IAB-MT of the mobile IAB node may share the gap configuration itself with its parent IAB-DU via RRC signalling. In other words, the first infrastructure equipment may be configured to transmit, to one or more of the plurality of other infrastructure equipment which are responsible for scheduling resources for the first infrastructure equipment, an indication of the configuration of the one or more pre-defined gap periods.

Generally, there is little need for this gap configuration to be shared with the mobile IAB node’s downstream IAB node or UEs it is responsible for serving, as any data to be transmitted to or from these downstream IAB nodes or UEs is scheduled by this mobile IAB node itself, and accordingly it can avoid scheduling any data during the gap period(s). However, in some arrangements of embodiments of the present technique, the gap information may be shared with the mobile IAB node’s downstream IAB node(s) (by either the IAB donor node or the mobile IAB node itself), for example, via system information or dedicated signalling, so that the mobile IAB node’s downstream IAB nodes can trigger local re-routing for that period, since these downstream IAB nodes can now freely schedule transmissions to/from their downstream nodes during these gap period(s) without having to worry about the mobile IAB node (i.e. their parent node) scheduling transmissions or choose another upstream node to act as a parent node instead of the mobile IAB node, where the new parent node is not currently performing measurements during a gap period, so as to avoid delays in transmitting/receiving data. In other words, the first infrastructure equipment may be configured to transmit, to one or more of the plurality of other infrastructure equipment for which the first infrastructure equipment is responsible for scheduling resources, an indication of the configuration of the one or more pre-defined gap periods.

In some arrangements of embodiments of the present technique, the first infrastructure equipment (which may be a mobile IAB node) may not be configured with any such measurement gap periods at all.

Instead, the first infrastructure equipment (e.g. IAB-DU) may comprise additional circuitry/hardware which is implemented so as to be able to perform the interference monitoring configured by the network (i.e. the “listening mode”) separately and at the same time as the main circuitry/hardware of the first infrastructure equipment is performing the transmission/reception of data or control signals. In other words, the base station part of the first infrastructure equipment may comprise dedicated circuitry which is configured by the wireless communications network to monitor interference within the first cell.

The method begins in step S 1. The method comprises, in step S2, moving from a first geographical location to a second geographical location, wherein an identifier of the first cell is the same as an identifier of a second cell formed by one of the other infrastructure equipment which neighbours the first infrastructure equipment when the first infrastructure equipment is located at the second geographical location. In step S3, the process comprises transmitting, to a node of the wireless communications network (e.g. to an IAB donor node, to a CU of the network, or to the core network via the IAB donor node), a signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell. The method then comprises, in step S4, receiving, from the node of the wireless communications network (e.g. from the IAB donor node, from the CU of the network, or from the core network via the IAB donor node), an indication of a new identifier that has been allocated to the first cell, the new identifier being different to the identifier of the second cell. The process ends in step S5.

Those skilled in the art would appreciate that the method shown by Figure 11 may be adapted in accordance with embodiments of the present technique. For example, other intermediate steps may be included in this method, or the steps may be performed in any logical order. Furthermore, though embodiments of the present technique have been described largely by way of the example communications system shown in Figure 10, it would be clear to those skilled in the art that they could be equally applied to other systems to those described herein. For example, as described above, it would be readily apparent to those skilled in the art that - though the example of Figure 10 is described with respect to a mobile IAB node - the present invention has applications broader than this, and relates to the detection and avoidance of PCI collisions for any kind of (mobile) network infrastructure equipment whether or not they are IAB nodes.

Those skilled in the art would further appreciate that such infrastructure equipment as herein defined may be further defined in accordance with the various arrangements and embodiments discussed in the preceding paragraphs. It would be further appreciated by those skilled in the art that such infrastructure equipment as herein defined and described may, without departing from the scope of the claims, form part of communications systems other than those defined by the present disclosure. The following numbered paragraphs provide further example aspects and features of the present technique:

Paragraph 1. A method of operating a first infrastructure equipment forming a first cell and forming part of a wireless communications network comprising a plurality of other infrastructure equipment each forming a cell, the first infrastructure equipment comprising one or both of a base station part and a mobile terminal part, wherein the method comprises moving from a first geographical location to a second geographical location, wherein an identifier of the first cell is the same as an identifier of a second cell formed by one of the other infrastructure equipment which neighbours the first infrastructure equipment when the first infrastructure equipment is located at the second geographical location, transmitting, to a node of the wireless communications network, a signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell, and receiving, from the node of the wireless communications network, an indication of a new identifier that has been allocated to the first cell, the new identifier being different to the identifier of the second cell.

Paragraph 2. A method according to Paragraph 1, wherein the first infrastructure equipment is an integrated access and backhaul, IAB, node comprising both of the base station part and the mobile terminal part, the first infrastructure equipment being configured to communicate with one or more of the plurality of other infrastructure equipment via a backhaul communications link, and wherein one of the plurality of other infrastructure equipment is the node of the wireless communications network, the node of the wireless communications network being an IAB donor node communicatively coupled to a core network part of the wireless communications network.

Paragraph 3. A method according to Paragraph 1 or Paragraph 2, wherein one or more of the first infrastructure equipment and plurality of other infrastructure equipment are each configured to serve one or more communications devices.

Paragraph 4. A method according to any of Paragraphs 1 to 3, wherein the node of the wireless communications network is a central unit, CU, node.

Paragraph 5. A method according to any of Paragraphs 1 to 3, wherein the node of the wireless communications network is an operations, administration, and maintenance, 0AM, entity.

Paragraph 6. A method according to any of Paragraphs 1 to 5, comprising transmitting, to the node of the wireless communications network, a location report indicating a geographical location of the first infrastructure equipment, wherein the location report, when the geographical location of the first infrastructure equipment is the second geographical location, is the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell.

Paragraph 7. A method according to Paragraph 6, wherein the node of the wireless communications network to which the location report is transmitted is a location management function, LMF, entity. Paragraph 8. A method according to Paragraph 7, wherein the node of the wireless communications network from which the indication of the new identifier that has been allocated to the first cell is received is an 0AM entity.

Paragraph 9. A method according to any of Paragraphs 6 to 8, wherein the location report is transmitted by the mobile terminal part of the first infrastructure equipment.

Paragraph 10. A method according to Paragraph 9, wherein the location report is transmitted by the mobile terminal part of the first infrastructure equipment to the node of the wireless communications network via radio resource control, RRC, signalling.

Paragraph 11. A method according to any of Paragraphs 6 to 10, wherein the location report is transmitted by the base station part of the first infrastructure equipment. Paragraph 12. A method according to Paragraph 10, wherein the location report is transmitted by the base station part of the first infrastructure equipment to the node of the wireless communications network via Fl application protocol, F1AP, signalling.

Paragraph 13. A method according to any of Paragraphs 6 to 12, wherein the location report is transmitted by the first infrastructure equipment based on the first infrastructure equipment determining that the first infrastructure equipment has moved more than a predetermined threshold distance from a previous geographical location from which the first infrastructure equipment last transmitted a location report.

Paragraph 14. A method according to any of Paragraphs 6 to 13, wherein the location report is transmitted by the first infrastructure equipment based on the first infrastructure equipment determining that the first infrastructure equipment has moved into a specific geographical area.

Paragraph 15. A method according to any of Paragraphs 6 to 14, wherein the location report is transmitted by the first infrastructure equipment based on the first infrastructure equipment determining that a predetermined time has passed since the first infrastructure equipment last transmitted a location report.

Paragraph 16. A method according to any of Paragraphs 6 to 15, wherein the location report is transmitted by the first infrastructure equipment based on the first infrastructure equipment detecting a level of interference exceeding a predefined threshold level.

Paragraph 17. A method according to any of Paragraphs 6 to 16, wherein the location report is transmitted by the first infrastructure equipment based on the first infrastructure equipment determining that a distance between the first infrastructure equipment and at least one of the plurality of other infrastructure equipment is decreasing.

Paragraph 18. A method according to any of Paragraphs 1 to 17, comprising detecting interference at the first infrastructure equipment, transmitting, to the node of the wireless communications network, an indication of the detected interference at the first infrastructure equipment, wherein the indication of the detected interference at the first infrastructure equipment is the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell.

Paragraph 19. A method according to Paragraph 18, comprising determining, based on the detected interference at the first infrastructure equipment, that the identifier of the first cell is the same as the identifier of the second cell.

Paragraph 20. A method according to Paragraph 18 or Paragraph 19, wherein the mobile terminal part of the first infrastructure equipment is configured by the wireless communications network to perform interference measurements, and wherein the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell is transmitted by the mobile terminal part of the first infrastructure equipment when a level of the detected interference exceeds a predefined threshold level.

Paragraph 21. A method according to Paragraph 20, wherein the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell is transmitted by the mobile terminal part of the first infrastructure equipment to the node of the wireless communications network via RRC signalling.

Paragraph 22. A method according to any of Paragraphs 18 to 21 , wherein the base station part of the first infrastructure equipment is configured by the wireless communications network to monitor interference within the first cell, and wherein the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell is transmitted by the base station part of the first infrastructure equipment based on the monitored interference. Paragraph 23. A method according to Paragraph 22, wherein the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell is transmitted by the base station part of the first infrastructure equipment to the node of the wireless communications network via F1AP signalling.

Paragraph 24. A method according to Paragraph 22 or Paragraph 23, wherein the base station part of the first infrastructure equipment is configured by the wireless communications network to monitor interference within the first cell during one or more pre-defined gap periods during which the base station part of the first infrastructure equipment does not transmit or receive any signals.

Paragraph 25. A method according to Paragraph 24, comprising receiving, from the node of the wireless communications network, a configuration of the one or more pre-defined gap periods.

Paragraph 26. A method according to Paragraph 25, wherein the configuration of the one or more predefined gap periods comprises an indication of a location in time and/or frequency of the one or more predefined gap periods.

Paragraph 27. A method according to Paragraph 25 or Paragraph 26, wherein the configuration of the one or more pre-defined gap periods comprises a duration for which the first infrastructure equipment is to monitor the interference within the first cell during the one or more pre-defined gap periods.

Paragraph 28. A method according to any of Paragraphs 25 to 27, wherein the configuration of the one or more pre-defined gap periods comprises a periodicity and/or repetition of the one or more pre-defined gap periods.

Paragraph 29. A method according to any of Paragraphs 25 to 28, wherein the configuration of the one or more pre-defined gap periods comprises an indication of a condition to be met, wherein when the condition is met the first infrastructure equipment is to monitor the interference within the first cell during the one or more pre-defined gap periods.

Paragraph 30. A method according to Paragraph 29, wherein the condition to be met is a threshold level of the interference.

Paragraph 31. A method according to Paragraph 29 or Paragraph 30, wherein the condition to be met is a geographical location of the first infrastructure equipment.

Paragraph 32. A method according to any of Paragraphs 25 to 31, comprising transmitting, to one or more of the plurality of other infrastructure equipment which are responsible for scheduling resources for the first infrastructure equipment, an indication of the configuration of the one or more pre-defined gap periods.

Paragraph 33. A method according to any of Paragraphs 25 to 32, comprising transmitting, to one or more of the plurality of other infrastructure equipment for which the first infrastructure equipment is responsible for scheduling resources, an indication of the configuration of the one or more pre-defined gap periods.

Paragraph 34. A method according to any of Paragraphs 22 to 33, wherein the base station part of the first infrastructure equipment comprises dedicated circuitry which is configured by the wireless communications network to monitor interference within the first cell.

Paragraph 35. A first infrastructure equipment forming a first cell and forming part of a wireless communications network comprising a plurality of other infrastructure equipment each forming a cell, the first infrastructure equipment comprising one or both of a base station part and a mobile terminal part, the first infrastructure equipment comprising transceiver circuitry configured to transmit signals and receive signals, and controller circuitry configured in combination with the transceiver circuitry to move from a first geographical location to a second geographical location, wherein an identifier of the first cell is the same as an identifier of a second cell formed by one of the other infrastructure equipment which neighbours the first infrastructure equipment when the first infrastructure equipment is located at the second geographical location, to transmit, to a node of the wireless communications network, a signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell, and to receive, from the node of the wireless communications network, an indication of a new identifier that has been allocated to the first cell, the new identifier being different to the identifier of the second cell.

Paragraph 36. Circuitry for a first infrastructure equipment forming a first cell and forming part of a wireless communications network comprising a plurality of other infrastructure equipment each forming a cell, the first infrastructure equipment comprising one or both of a base station part and a mobile terminal part, the circuitry comprising transceiver circuitry configured to transmit signals and receive signals, and controller circuitry configured in combination with the transceiver circuitry to move from a first geographical location to a second geographical location, wherein an identifier of the first cell is the same as an identifier of a second cell formed by one of the other infrastructure equipment which neighbours the first infrastructure equipment when the first infrastructure equipment is located at the second geographical location, to transmit, to a node of the wireless communications network, a signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell, and to receive, from the node of the wireless communications network, an indication of a new identifier that has been allocated to the first cell, the new identifier being different to the identifier of the second cell.

Paragraph 37. A method of operating a second infrastructure equipment forming part of a wireless communications network comprising a plurality of other infrastructure equipment each forming a cell and each comprising one or both of a base station part and a mobile terminal part, wherein the method comprises receiving, from a first of the plurality of other infrastructure equipment based on the first infrastructure equipment having moved from a first geographical location to a second geographical location, a signal which indicates that an identifier of a first cell formed by the first infrastructure equipment might be the same as an identifier of a second cell formed by one of the other infrastructure equipment which neighbours the first infrastructure equipment when the first infrastructure equipment is located at the second geographical location, and transmitting, to the first infrastructure equipment, an indication of a new identifier that has been allocated to the first cell, the new identifier being different to the identifier of the second cell.

Paragraph 38. A method according to Paragraph 37, wherein the second infrastructure equipment is an integrated access and backhaul, IAB, donor node configured to communicate with one or more of the plurality of other infrastructure equipment via a backhaul communications link and being communicatively coupled to a core network part of the wireless communications network, and wherein the first infrastructure equipment is an IAB node configured to communicate with one or more of the plurality of other infrastructure equipment via a backhaul communications link.

Paragraph 39. A method according to Paragraph 37 or Paragraph 38, wherein one or more of the first infrastructure equipment, second infrastructure equipment, and plurality of other infrastructure equipment are each configured to serve one or more communications devices.

Paragraph 40. A method according to any of Paragraphs 37 to 39, wherein the second infrastructure equipment is a central unit, CU, node of the wireless communications network.

Paragraph 41. A method according to any of Paragraphs 37 to 39, wherein the second infrastructure equipment is an operations, administration, and maintenance, 0AM, entity.

Paragraph 42. A method according to Paragraph 41, wherein the second infrastructure equipment is configured to receive the location report from the first infrastructure equipment via a location management function, LMF, entity.

Paragraph 43. A method according to any of Paragraphs 37 to 42, comprising receiving, from the first infrastructure equipment, a location report indicating a geographical location of the first infrastructure equipment, wherein the location report, when the geographical location of the first infrastructure equipment is the second geographical location, is the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell.

Paragraph 44. A method according to Paragraph 43, wherein the second infrastructure equipment is an LMF entity.

Paragraph 45. A method according to Paragraph 43 or Paragraph 44, wherein the location report is received from the mobile terminal part of the first infrastructure equipment.

Paragraph 46. A method according to Paragraph 45, wherein the location report is received from the mobile terminal part of the first infrastructure equipment via radio resource control, RRC, signalling. Paragraph 47. A method according to any of Paragraphs 43 to 46, wherein the location report is received from the base station part of the first infrastructure equipment.

Paragraph 48. A method according to Paragraph 47, wherein the location report is received from the base station part of the first infrastructure equipment via Fl application protocol, F1AP, signalling. Paragraph 49. A method according to any of Paragraphs 43 to 48, wherein the location report is received from the first infrastructure equipment based on the first infrastructure equipment having moved more than a predetermined threshold distance from a previous geographical location from which the first infrastructure equipment last transmitted a location report.

Paragraph 50. A method according to any of Paragraphs 43 to 49, wherein the location report is received from the first infrastructure equipment based on the first infrastructure equipment having moved into a specific geographical area.

Paragraph 51. A method according to any of Paragraphs 43 to 50, wherein the location report is received from the first infrastructure equipment based on a predetermined time having passed since the first infrastructure equipment last transmitted a location report.

Paragraph 52. A method according to any of Paragraphs 43 to 51, wherein the location report is received from the first infrastructure equipment based on a level of interference at the first infrastructure equipment exceeding a predefined threshold level.

Paragraph 53. A method according to any of Paragraphs 43 to 52, wherein the location report is received from the first infrastructure equipment based on a distance between the first infrastructure equipment and at least one of the plurality of other infrastructure equipment decreasing.

Paragraph 54. A method according to any of Paragraphs 37 to 53, comprising transmitting, to the mobile terminal part of the first infrastructure equipment, an indication that the mobile terminal part of the first infrastructure equipment is to perform interference measurements, and receiving, from the mobile terminal part of the first infrastructure equipment when a level of detected interference at the first infrastructure equipment exceeds a predefined threshold level, an indication of the detected interference at the first infrastructure equipment, wherein the indication of the detected interference at the first infrastructure equipment is the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell.

Paragraph 55. A method according to Paragraph 54, wherein the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell is received from the mobile terminal part of the first infrastructure equipment via RRC signalling.

Paragraph 56. A method according to any of Paragraphs 37 to 55, comprising transmitting, to the base station part of the first infrastructure equipment, an indication that the base station part of the first infrastructure equipment is to monitor interference within the first cell, and receiving, from the base station part of the first infrastructure equipment, an indication of monitored interference within the first cell, wherein the indication of monitored interference within the first cell is the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell.

Paragraph 57. A method according to Paragraph 56, wherein the signal which indicates that the identifier of the first cell might be the same as the identifier of the second cell is received from the base station part of the first infrastructure equipment via F1AP signalling.

Paragraph 58. A method according to Paragraph 56 or Paragraph 57, comprising transmitting, to the first infrastructure equipment, a configuration of one or more pre-defined gap periods during which the base station part of the first infrastructure equipment is to monitor interference within the first cell, wherein the base station part of the first infrastructure equipment does not transmit or receive any signals during the one or more pre-defined gap periods.

Paragraph 59. A method according to Paragraph 58, wherein the configuration of the one or more predefined gap periods comprises an indication of a location in time and/or frequency of the one or more predefined gap periods.

Paragraph 60. A method according to Paragraph 58 or Paragraph 59, wherein the configuration of the one or more pre-defined gap periods comprises a duration for which the first infrastructure equipment is to monitor the interference within the first cell during the one or more pre-defined gap periods.

Paragraph 61. A method according to any of Paragraphs 58 to 60, wherein the configuration of the one or more pre-defined gap periods comprises a periodicity and/or repetition of the one or more pre-defined gap periods.

Paragraph 62. A method according to any of Paragraphs 58 to 61, wherein the configuration of the one or more pre-defined gap periods comprises an indication of a condition to be met, wherein when the condition is met the first infrastructure equipment is to monitor the interference within the first cell during the one or more pre-defined gap periods.

Paragraph 63. A method according to Paragraph 62, wherein the condition to be met is a threshold level of the interference.

Paragraph 64. A method according to Paragraph 62 or Paragraph 63, wherein the condition to be met is a geographical location of the first infrastructure equipment.

Paragraph 65. A method according to any of Paragraphs 58 to 64, comprising transmitting, to the first infrastructure equipment, an indication that the first infrastructure equipment is to transmit an indication of the configuration of the one or more pre-defined gap periods to one or more of the plurality of other infrastructure equipment which are responsible for scheduling resources for the first infrastructure equipment.

Paragraph 66. A method according to any of Paragraphs 58 to 65, comprising transmitting, to one or more of the plurality of other infrastructure equipment which are responsible for scheduling resources for the first infrastructure equipment, an indication of the configuration of the one or more pre-defined gap periods.

Paragraph 67. A method according to any of Paragraphs 58 to 66, comprising transmitting, to the first infrastructure equipment, an indication that the first infrastructure equipment is to transmit an indication of the configuration of the one or more pre-defined gap periods to one or more of the plurality of other infrastructure equipment for which the first infrastructure equipment is responsible for scheduling resources.

Paragraph 68. A method according to any of Paragraphs 58 to 67, comprising transmitting, to one or more of the plurality of other infrastructure equipment for which the first infrastructure equipment is responsible for scheduling resources, an of the configuration of the one or more pre-defined gap periods.

Paragraph 69. A method according to any of Paragraphs 56 to 68, wherein the base station part of the first infrastructure equipment comprises dedicated circuitry which is configured by the wireless communications network to monitor interference within the first cell. Paragraph 70. A second infrastructure equipment forming part of a wireless communications network comprising a plurality of other infrastructure equipment each forming a cell, the second infrastructure equipment comprising one or both of a base station part and a mobile terminal part, the second infrastructure equipment comprising transceiver circuitry configured to transmit signals and receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first of the plurality of other infrastructure equipment based on the first infrastructure equipment having moved from a first geographical location to a second geographical location, a signal which indicates that an identifier of a first cell formed by the first infrastructure equipment might be the same as an identifier of a second cell formed by one of the other infrastructure equipment which neighbours the first infrastructure equipment when the first infrastructure equipment is located at the second geographical location, and to transmit, to the first infrastructure equipment, an indication of a new identifier that has been allocated to the first cell, the new identifier being different to the identifier of the second cell.

Paragraph 71. Circuitry for a second infrastructure equipment forming part of a wireless communications network comprising a plurality of other infrastructure equipment each forming a cell, the second infrastructure equipment comprising one or both of a base station part and a mobile terminal part, the circuitry comprising transceiver circuitry configured to transmit signals and receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first of the plurality of other infrastructure equipment based on the first infrastructure equipment having moved from a first geographical location to a second geographical location, a signal which indicates that an identifier of a first cell formed by the first infrastructure equipment might be the same as an identifier of a second cell formed by one of the other infrastructure equipment which neighbours the first infrastructure equipment when the first infrastructure equipment is located at the second geographical location, and to transmit, to the first infrastructure equipment, an indication of a new identifier that has been allocated to the first cell, the new identifier being different to the identifier of the second cell.

Paragraph 72. A telecommunications system comprising a first infrastructure equipment according to Paragraph 35 and a second infrastructure equipment according to Paragraph 70.

Paragraph 73. A computer program comprising instructions which, when loaded onto a computer, cause the computer to perform a method according any of Paragraphs 1 to 34 or Paragraphs 37 to 69.

Paragraph 74. A non-transitory computer-readable storage medium storing a computer program according to Paragraph 73.

It will be appreciated that the above description for clarity has described embodiments with reference to different functional units, circuitry and/or processors. However, it will be apparent that any suitable distribution of functionality between different functional units, circuitry and/or processors may be used without detracting from the embodiments.

Described embodiments may be implemented in any suitable form including hardware, software, firmware or any combination of these. Described embodiments may optionally be implemented at least partly as computer software running on one or more data processors and/or digital signal processors. The elements and components of any embodiment may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the disclosed embodiments may be implemented in a single unit or may be physically and functionally distributed between different units, circuitry and/or processors. Although the present disclosure has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognise that various features of the described embodiments may be combined in any manner suitable to implement the technique.

References

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