Accessing nes cell with random access

Abstract

A method of operating a communications device is provided. The method comprises receiving, from a first infrastructure equipment while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to a wireless communications network via a second infrastructure equipment, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network and the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, connecting, based on receiving the system information from the first infrastructure equipment, to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and transmitting signals to and / or receiving signals from the second infrastructure equipment after the communications device has connected to the wireless communications network via the second infrastructure equipment.

Description

[0001] ACCESSING NES CELL WITH RANDOM ACCESS

[0002] BACKGROUND Field of Disclosure

[0003] The present disclosure relates to communications devices and infrastructure equipment of wireless communications networks and methods of operating such communications devices and infrastructure equipment for the more efficient performance of network access procedures by such communications devices.

[0004] The present application claims the Paris Convention priority from European patent application number EP23190322.0, filed on 8 August 2023, the contents of which are hereby incorporated by reference.

[0005] Description of Related Art

[0006] 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.

[0007] Previous 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.

[0008] Current and future wireless communications networks are 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, extended Reality (XR) 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).

[0009] In view of this there is expected to be a desire for current wireless communications networks, for example those which may be referred to as 5G or new radio (NR) systems / new radio access technology (RAT) systems, or indeed future 6G wireless communications, 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. The desire to support these new use-cases and scenarios gives rise to new challenges for efficiently handling communications in wireless communications systems that need to be addressed.

[0010] SUMMARY OF THE DISCLOSURE

[0011] The present disclosure can help address or mitigate at least some of the issues discussed above.

[0012] Some embodiments of the present technique can provide a method of operating a communications device. The method comprises receiving, from a first infrastructure equipment while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to a wireless communications network via a second infrastructure equipment, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network and the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the nonanchor cell being a network energy saving, NES, cell, connecting, based on receiving the system information from the first infrastructure equipment, to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and transmitting signals to and / or receiving signals from the second infrastructure equipment after the communications device has connected to the wireless communications network via the second infrastructure equipment.

[0013] Such embodiments of the present technique, which, in addition to methods of operating communications devices, relate to methods of operating infrastructure equipment, to communications devices and infrastructure equipment, to circuitry for communications devices and infrastructure equipment, to wireless communications systems, to computer programs, and to computer-readable storage mediums, can allow for the more efficient performance of network access procedures by such communications devices.

[0014] Respective aspects and features of the present disclosure are defined in the appended claims.

[0015] 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.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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:

[0018] 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;

[0019] Figure 2 schematically represents some aspects of an NR-type wireless telecommunications system which may be configured to operate in accordance with certain embodiments of the present disclosure;

[0020] 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;

[0021] Figure 4 is a message flow diagram showing a typical four-step random access (RACH) procedure; Figure 5 is a message flow diagram showing a typical two-step RACH procedure;

[0022] Figure 6 is reproduced from [8], and illustrates how a user equipment (UE) may be redirected by an anchor cell to a non-anchor cell after setup of an RRC connection with the anchor cell;

[0023] Figure 7 is reproduced from [8], and illustrates how a UE may be redirected by an anchor cell to a nonanchor cell before setup of an RRC connection with the anchor cell;

[0024] Figure 8 shows a part schematic, part message flow diagram representation of a wireless communications system comprising a communications device and an infrastructure equipment in accordance with embodiments of the present technique;

[0025] Figure 9 shows an example of how a UE may access a Network Energy Saving (NES) cell via an anchor cell using a four-step RACH procedure in accordance with embodiments of the present technique;

[0026] Figure 10 shows an example of how a UE may access an NES cell via an anchor cell using a two-step RACH procedure in accordance with embodiments of the present technique;

[0027] Figure 11 shows an example of how a UE may access an NES cell via the NES cell itself in accordance with embodiments of the present technique; and

[0028] Figure 12 shows a flow diagram illustrating an example process of communications in a communications system in accordance with embodiments of the present technique.

[0029] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Long Term Evolution Advanced Radio Access Technology (4G)

[0031] 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.

[0032] The network 6 includes a plurality of base stations 1 connected to a core network 2, which may be for example an Evolved Packet Core (EPC). 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.

[0033] 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, eNodeBs, eNB, gNodeBs, 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.

[0034] New Radio Access Technology (5G)

[0035] 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 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 be for example referred to as 5GC) 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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 49, a receiver 48 and a controller 44 which is configured to control the transmitter 49 and the receiver 48 to transmit signals representing uplink data to the wireless communications network via the wireless access interface formed by the TRP 10 and to receive downlink data as signals transmitted by the transmitter 30 and received by the receiver 48 in accordance with the conventional operation.

[0042] The transmitters 30, 49 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.

[0043] As shown in Figure 3, the TRP 10 also includes a network interface 50 which connects to the DU 42 via a physical interface 16. The network interface 50 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.

[0044] 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 3GPP technical specifications [2] and [3], 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 50 of the TRP 10 to the DU 42 and the Fl interface 46 from the DU 42 to the CU 40.

[0045] As will be appreciated by those acquainted with 5G architecture, the CU 40 may be a logical node which hosts Radio Resource Control (RRC) protocols, Service Data Adaptation Protocols (SDAP), and Packet Data Convergence Protocols (PDCP) of a gNB. Alternatively, the CU 40 may be a logical node which hosts RRC and PDCP protocols of an en-gNB (which is a gNB that is able to connect with both EPC and eNBs and can be understood as being, for example, a secondary node (SgNB) used in dual connectivity scenarios). The CU 40 partly controls the operation of one or more DUs 40 and terminates the Fl interface 46 for the DUs that it controls. The DU 42 may be a logical node which hosts Radio Link Control (RLC), Medium Access Control (MAC), and Physical (PHY) layers of a gNB or en-gNB. The operation of the DU 42 is partly controlled by the CU 40 for which the DU 42 terminates the Fl interface 46.

[0046] Although not shown in Figures 2 or 3, it will be familiar to those acquainted with 5G architecture that the CU 40 may be further split into a CU-CP which performs the control plane functions of the CU 40 and a CU-UP which performs the user plane functions of the CU 40 (see for example, [4]). In more detail, the CU-CP may be a logical node hosting an RRC protocol and a control plane part of a PDCP protocol of the CU 40 for the gNB or en-gNB. The CU-CP terminates an El interface connected with the CU-UP and an Fl-C interface connected with the DU 42. As will be appreciated, the Fl-C interface carries control plane signalling of the Fl interface 46. The CU-UP may be a logical node which hosts a user plane part of a PDCP protocol of the CU 40 for an en-gNB. Alternatively, the CU-UP may be a logical node which hosts a user plane part of the PDCP protocol and an SDAP protocol of the CU 40 for a gNB. The CU-UP terminates an El interface connected with the CU-CP and an Fl-U interface connected with the DU 42. As will be appreciated, the Fl-U interface carries user plane signalling of the Fl interface 46.

[0047] Random Access (RACH) Procedures

[0048] In wireless telecommunications networks, such as LTE and NR type networks, there are different Radio Resource Control (RRC) modes for terminal devices. For example, it is common to support an RRC idle mode (RRC IDLE) and an RRC connected mode (RRC CONNECTED). A terminal device in the idle mode may transition to connected mode, for example because it needs to transmit uplink data or respond to a paging request, by undertaking a random access procedure. The random access procedure involves the terminal device transmitting a preamble on a physical random access channel, and so the procedure is commonly referred to as a RACH or PRACH procedure / process.

[0049] In addition to a terminal device deciding itself to initiate a random access procedure to connect to the network, it is also possible for the network, e.g. a base station, to instruct a terminal device in connected mode to initiate a random access procedure by transmitting to the terminal device an instruction to do so. Such an instruction is sometimes referred to as a PDCCH order (Physical Downlink Control Channel order). There are various scenarios in which a network triggered RACH procedure (PDCCH order) may arise.

[0050] Figure 4 shows atypical four-step RACH procedure used in LTE systems such as that described by reference to Figure 1 which could also be applied to an NR wireless communications system such as that described by reference to Figure 2. A communications device (or UE), which could be in an inactive or idle mode, may have some data which it needs to send to the network. To do so, the UE sends a random access preamble 51 (message 1) to a gNB. This random access preamble 51 indicates the identity of the communications device to the gNB, such that the gNB can address the communications device during later stages of the RACH procedure. Assuming the random access preamble 51 is successfully received by the gNB, the gNB will transmit a random access response 52 message (message 2) to the communications device(s) based on the identity indicated in the received random access preamble 51. The random access response 52 message carries a further identity which is assigned by the gNB to identify the communications device, as well as a timing advance value such that the communications device can change its timing to compensate for the round trip delay caused by its distance from the gNB and grant uplink resources for the communications device to transmit the data in.

[0051] Following the reception of the random access response message 52, the communications device transmits the scheduled transmission of data 53 to the gNB (message 3), using the identity assigned to it in the random access response message 52. Assuming there are no collisions with other UEs, which may occur if another UE and the communications device send the same random access preamble 51 to the gNB at the same time and using the same frequency resources, the scheduled transmission of data 53 is successfully received by the gNB. The gNB will respond to the scheduled transmission 53 with a contention resolution message 54 (message 4).

[0052] In 5G / NR systems, an “inactive” RRC state (RRC_INACTIVE) may be used, where a UE is able to start data transfer with a low delay in the inactive state without transition to a connected state. Various possible solutions have been proposed to permit this, one of which is a two-step RACH procedure. As will be appreciated, compared with the four-step RACH process, the two-step RACH process can provide a facility for transmitting data more quickly. Accordingly, it has been proposed to develop general MAC procedures covering both physical layer and higher layer aspects for the two-step RACH process. In general, the benefit of the two-step RACH procedure compared with the four-step PRACH procedure is to reduce the time it takes for connection setup / resume procedure. For example, in an ideal situation, the two-step RACH will reduce the latency by halving the number of steps from four to two for initial access UEs. In addition, it is considered that a two-step RACH procedure has potential benefits for channel access in NR unlicensed spectrum (NR-U).

[0053] Broadly, the two-step RACH allows the combination of the transmission of the random access preamble 51 with the transmission of data 53 of Figure 4 as an initial transmission (“Message A” or “MsgA”), and similarly the combination of the transmission of the random access response 52 and contention resolution message 54 as a response (“Message B”, or “MsgB”). A fallback procedure may be provided to allow a RACH procedure which is started according to the specifications for a two-step RACH to instead proceed according to the four-step RACH procedure. Two-step RACH may be applicable for communications devices in the RRC INACTIVE, RRC CONNECTED and RRC IDLE states.

[0054] A message flow diagram illustrating the two-step RACH process is shown in Figure 5. As its name suggests, in the two-step RACH process, there are only two-steps as noted above. In the first step, the UE transmits a Message A 55 which comprises a RACH preamble 56 and data 57. The data 57 is transmitted on a shared uplink channel, such as a physical uplink shared channel, PUSCH that in a four-step RACH procedure would be transmitted in Message 3. More specifically, the choice of a particular preamble 56 may pre-configure the communications device to transmit the data 57 in pre-configured resources of the uplink shared channel. In the second step, the base station, having successfully received the Message A 55, responds with a Message B 58 which incorporates both a RAR, as would be carried by message 2 of the four-step RACH procedure described above, and the corresponding contention resolution and / or data (PDSCH) that in a four-step RACH procedure would be transmitted in Message 4.

[0055] Network Energy Saving (NES)

[0056] In Release- 18 of the 3PP standards, a new study item [5] was initiated on Network Energy Saving (NES). The objectives of the study item are the following:

[0057] (i) Defining a base station energy consumption model;

[0058] (ii) Defining of an evaluation methodology and Key Performance Indicators (KPIs); and

[0059] (iii) Identifying techniques on the gNB and UE side to improve network energy savings in terms of both base station transmission and reception.

[0060] Objective (i) is expected to include adapting frameworks of power consumption modelling and evaluation methodologies for UE power saving in NR (discussed in [6]) to the base station side. This is expected to involve adapting relative energy consumption for DL and UL (considering factors such as Power Amplifier (PA) efficiency, number of TXRU interfaces, base station load, etc), sleep states and associated transition times, and one or more reference parameters / configurations.

[0061] Objective (ii) is expected to include targeting the evaluation methodology for evaluating system-level network energy consumption and energy savings gains, as well as assessing / balancing impact to network and user performance (for example, spectral efficiency, capacity, User Perceived Throughput (UPT), latency, handover performance, call drop rate, initial access performance, Service Level Agreement (SLA) assurance related KPIs), energy efficiency, UE power consumption, and complexity. The evaluation methodology is expected to focus on reusing existing KPIs whenever applicable, rather than focussing on a single KPI. Where existing KPIs are found to be insufficient, new KPIs may be developed as needed. It has yet to be determined which KPIs will be evaluated and how.

[0062] Objective (iii) is expected to include achieving efficient operation dynamically and / or semi-statically and finer granularity adaptation of transmissions and / or receptions in one or more of network energy saving techniques in time, frequency, spatial, and power domains, with potential support / feedback from UE, and potential UE assistance information. Objective (iii) is also expected to include information exchange / coordination over network interfaces.

[0063] The study item [5] is expected to prioritise idle / empty and low / medium load scenarios, with different loads among carriers and neighbour cells being permitted. The exact definition of such loads is expected to be determined as part of the study item. The following examples of single-carrier and multi-carrier deployments are expected to be prioritised in the study item:

[0064] • Urban micro in FR1, including Time Division Duplex (TDD) massive Multiple-Input Multiple- Output (MIMO). This can also model small cells;

[0065] • FR2 beam-based scenarios (note: this scenario can also model small cells);

[0066] • Urban / Rural macro in FR1 with / without DSS Dynamic Spectrum Sharing (DSS). No impact to LTE expected in case of DSS; and

[0067] • Evolved-Universal Terrestrial Radio Access-New Radio Dual Connectivity (EN-DC)ZNew Radio Dual Connectivity (NR-DC) macro with Frequency Division Duplex (FDD) Primary Cell (PCell) and TDD / Massive MIMO on higher FR1 / FR2 frequency.

[0068] It intended that existing UEs will be able to continue accessing a network implementing Release- 18 network energy savings techniques, with the possible exception of techniques developed specifically for greenfield deployments.

[0069] NES Modes

[0070] It has been proposed that cells provided by infrastructure equipment of a wireless communications network are configured to operate in accordance with NES modes. Table 1 (which is reproduced from [7]) illustrates examples of proposed NES modes.

[0071] Table 1. Proposed NES modes

[0072] In Table 1, the transition time, T, for an NES mode is the time taken for a cell to enter or leave that NES mode. The additional transition energy, E, for an NES mode is the energy required for a cell to enter or leave that NES mode relative to a reference energy. The relative power, P, of an NES mode is the power consumed when a cell enters of leaves that NES mode relative to a reference power.

[0073] As will be understood by one skilled in the art, the relative power for the deep sleep NES mode is lower than the relative power for the light sleep NES mode which is lower than the relative power for micro sleep NES mode. In other words, Pl < P2 < P3. Furthermore, as will be understood by one skilled in the art, the relative power of the active UL NES mode has a lower relative power than the active DL NES mode. In other words, P5 < P4.

[0074] Table 2 (reproduced from [7]) illustrates examples of relative power, P, values for the NES modes shown in Table 1 across different base station categories and reference configuration sets. Further detail on the base station categories and the reference configuration sets can be found in [7] .

[0075] In addition to NES modes proposed in Table 1, other NES modes are envisaged. For example, a cell may be configured to operate in accordance with an NES mode which has a relative power lower than the deep sleep NES mode and requires a larger transition time. This may be referred to as a hibernating sleep, or Quasi-off, NES mode. Another example of an NES mode is an “OFF” NES mode where the cell is turned off for uplink and downlink data transmissions. As will be understood by one skilled in the art, a communications device in a cell in an OFF NES mode may still receive reference signals or send wakeup signal to wake up the cell. It would also be appreciated by those skilled in the art that a NES cell is a cell that is able to support NES technologies and configurations, but which does not necessarily have to be operating in accordance with a NES mode (such as those described herein) at all times.

[0076] Configuring network cells to operate in accordance with NES modes is expected to improve network energy savings. For example, in accordance with a network planning strategy, different cells in a wireless communications network may operate according to different NES modes. For example, a cell may be configured in a micro sleep NES mode when uplink / downlink traffic is expected imminently in the cell and another cell may be configured in a deep sleep NES mode when uplink / downlink traffic is not expected in the cell for considerable time.

[0077] SSB / SIB-less NES Cells

[0078] The concept of NES cells without system information blocks (SIBs), where the UE is in coverage of an anchor cell (i.e. one which does support SIB) and one or more non-anchor NES cells (which do not support SIB), is something which is described in [7], and particularly in section 6. 1.7 of [7], upon which the following description of the higher layer procedures for SIB-less and SSB / SIB-less NES cells is based.

[0079] The concept of non-anchor NES cell without SIB is only applicable in the multi-carrier scenario, where the UE is in coverage of both an anchor cell and one or multiple non-anchor NES cell(s). An anchor cell is a cell where a UE is capable of receiving synchronisation signal blocks (SSBs), system information, and paging. A non-anchor NES cell without SIB is a cell in which the UE cannot receive SIB. A non- anchor NES cell without SSB and SIB is a cell where a UE cannot receive either SSB or SIB. Depending on the design, the UE’s network access may occur only via the anchor cell, or via the anchor cell and also directly via the non-anchor NES cell. If access directly through a non-anchor NES cell is supported, the SIBs transmitted to the UE by the anchor cell may also include the necessary information to access the non-anchor NES cell (as this does not support the transmission of such SIBs to the UE itself).

[0080] A UE camps on an anchor cell, not on a non-anchor NES cell without SIB (or without both SSB and SIB) - even if the UE is able to access the network directly through that non-anchor cell. Paging on a non- anchor NES cell without SIB or a non-anchor NES cell without SSB and SIB is not supported. This means that it is not possible to page a UE through a non-anchor NES cell to instruct it, for example, to perform a RACH procedure (such as those described above with respect to Figures 4 and 5) in order to set up an RRC connection with that non-anchor NES cell. Two options through which RACH may be supported in the multi -carrier scenario with an anchor cell and a non-anchor NES cell are described in [8], from which the description of such options is reproduced below. Each of the options described in [8] propose that a UE is redirected to a non-anchor cell from an anchor cell.

[0081] In the first of these options, which is illustrated by Figure 6, the UE is initially receiving SSBs and SIBs from the anchor cell whilst in the idle or inactive mode. At some point, the UE performs a RACH procedure with the anchor cell to transition into the connected mode. Here, the intention is that the UE camps on the non-anchor cell, but because the non-anchor (NES) cell does not support SIB or SSB, the UE cannot receive paging instructions from that non-anchor cell to perform the RACH procedure with it rather than with the anchor cell. Accordingly, after the RACH procedure, the anchor cell instructs the UE via RRC signalling to redirect to the non-anchor cell, and so at this point, the UE is able to perform a RACH procedure with the non-anchor cell to enter into the connected state with that non-anchor cell. After this, the UE is able to exchange data traffic with the network via the non-anchor cell.

[0082] In the second option, which is illustrated by Figure 7, again, the UE is initially receiving SSBs and SIBs from the anchor cell whilst in the idle or inactive mode. At some point, the UE is instructed (or decides) to perform a RACH procedure to connect to the anchor node - but here, the RACH procedure itself includes a redirection instruction to redirect to the non-anchor cell. Here, therefore, before completing the RACH procedure with the anchor cell, the UE is able to perform a RACH procedure with the non- anchor cell to enter into the connected state with that non-anchor cell. After this, the UE is able to exchange data traffic with the network via the non-anchor cell.

[0083] In both cases (as illustrated by Figure 6 and Figure 7) it is necessary for the UE to initially perform a RACH procedure with the anchor cell - even if such a RACH procedure is not completed in the second option. Then, after this, the UE will perform the entire RACH procedure to connect to the non-anchor cell after receiving an instruction to redirect to that non-anchor cell (either in an RRC reconfiguration command after the UE is connected to the network via the anchor cell or, in the case of the second option, in the random access response message or the like during the RACH procedure performed with the anchor cell).

[0084] Here, therefore, even though the procedure illustrated by Figure 7 is more efficient than that shown by Figure 6 - because the RACH procedure with the anchor cell does not need to be completed - in both cases the UE will need to initiate (or complete) two RACH procedures (i.e., one with each of the anchor or non-anchor cell). Generally speaking, despite the proposals made in [8], the access procedure for UEs to the network via SSB / SIB-less NES cells is still an open issue for which specification change may occur. Embodiments of the present technique therefore propose solutions and procedures for such UE access via non-anchor NES cells, which address the inefficiencies of the example procedures shown in Figure 6 and 7 (and described in [8]) by requiring the performance of only a single RACH procedure by the UE.

[0085] RACH Procedure for NES Cells

[0086] Figure 8 shows a part schematic, part message flow diagram representation of a first wireless communications system comprising a first infrastructure equipment (e.g. gNB) 81, a second infrastructure equipment (e.g. gNB) 82, and a communications device 83 (e.g. a UE 14) in accordance with at least some embodiments of the present technique. Here, the first and second infrastructure equipment 81, 82 may respectively control first and second cells of a wireless communications network, where the first cell is an anchor cell and the second cell is a non-anchor NES cell. Here, this communications device 83 may be an NES UE; i.e. a UE that is able to support functions of an NES cell such as the second cell controlled by the second infrastructure equipment 82, and thus is able to connect to such NES cells. The first infrastructure equipment 81, second infrastructure equipment 82, and communications device 83 each comprise atransceiver (or transceiver circuitry) 81.1, 82.1, 83.1, and a controller (or controller circuitry) 81.2, 82.2, 83.2. Each of the controllers 81.2, 82.2, 83.2 may be, for example, a microprocessor, a CPU, or a dedicated chipset, etc.

[0087] As shown in the example of Figure 8, the transceiver circuitry 83.1 and the controller circuitry 83.2 of the communications device 83 are configured in combination to receive 84, from the first infrastructure equipment 81 while the communications device 83 is operating in an idle mode (e.g. RRC IDLE), system information indicating that the communications device 83 is to connect to the wireless communications network via the second infrastructure equipment 82, to connect 86, based on receiving 84 the system information from the first infrastructure equipment 81, to the wireless communications network via the second infrastructure equipment 82 by performing a single random access procedure, and to transmit 87a signals to and / or to receive 87b signals from the second infrastructure equipment 82 after the communications device 83 has connected to the wireless communications network via the second infrastructure equipment 82. Here, the single random access procedure may be a random access procedure performed 86a with both the first infrastructure equipment 81 and the second infrastructure equipment 82 (and ending with the communications device 83 being connected to the network via the second infrastructure equipment 82), or alternatively, the single random access procedure may be a random access procedure performed 86b with only the second infrastructure equipment 82.

[0088] Prior to the communications device 83 connecting 86 to the wireless communications network via the second infrastructure equipment 82 by performing the random access procedure, the first infrastructure equipment 81 may transmit 85, to the second infrastructure equipment 82, an indication that the communications device 83 is to connect to the wireless communications network via the second infrastructure equipment 82 by performing the random access procedure - thus ensuring that the second infrastructure equipment 82 is ready and able to perform (at least part of) the random access procedure along with the communications device 83.

[0089] Essentially, such embodiments of the present technique as exemplified by Figure 8 propose solutions and procedures for UE access to networks via non-anchor NES cells by requiring the performance of only a single RACH procedure by the UE. Such solutions and procedures as described below (largely with reference to the message flow diagrams of Figures 9, 10, and 11) can improve the efficiency energy saving of NES cells or, where relatively few anchor cells are responsible for the SIB / SSB signalling for a high number of NES cells, improve the efficiency of such anchor cells.

[0090] Figure 9 shows an example of how a UE may access an NES cell via an anchor cell using a four-step RACH procedure in accordance with embodiments of the present technique. The reason for accessing the network via the anchor cell is to free the SSB-less NES cell from having to monitor the access channel (e.g. PRACH) used for RACH procedures, which provides a benefit in that the energy saving performance for SSB-less NES cells may be further improved. Given that the NES cell is unable to page the UE to initiate a RACH procedure with it, it is particularly inefficient for the NES cell to be monitoring for RACH preambles from the UE. Arrangements of embodiments of the present techniques such as those exemplified by Figure 9 therefore aim to optimise the involvement of the anchor and non-anchor cells in RACH procedures where possible.

[0091] In terms of preparation, before the RACH procedure itself is actually performed, the anchor cell will transmit SSB / SIBs to the UE, which may contain any necessary access information (for example, preambles, RACH resources of the anchor cell, etc.), as well as an indication to prompt and allow the UE to initiate the RACH procedure on the anchor cell with the intention being that the UE access the nonanchor NES cell at the end of that RACH procedure. Here, the anchor cell may reserve some RACH resources (or a certain periodicity for RACH procedures which is different to that used by normal UEs for access to anchor cells) for the purposes of use by NES UEs to access NES cells only. In other words, the system information comprises an indication of information to be used by the communications device to perform the random access procedure and / or an indication that the communications device is to initiate the random access procedure with the first infrastructure equipment and perform the random access procedure with both of the first infrastructure equipment and the second infrastructure equipment. Here, the information to be used by the communications device to perform the random access procedure may comprise: one or more random access preambles that the communications device is able to use to initiate the random access procedure, a location of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device, and a periodicity of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device. The information to be used by the communications device to perform the random access procedure may be specific to communications devices that are configured to connect to non-anchor NES cells. Furthermore, this access information may originate either from the anchor cell itself, or from the non-anchor NES cell, where it is indicated by the non-anchor NES cell to the anchor cell for the anchor cell to broadcast in SIBs or SSBs. In other words, the information to be used by the communications device to perform the random access procedure may be generated by the first infrastructure equipment or may be received by the first infrastructure equipment from the second infrastructure equipment.

[0092] As can be seen in the example of Figure 9, the UE 93 first transmits 94 a random access preamble to the anchor cell 91, and receives 95 a RAR in response to the transmitted preamble, where such a RAR may comprise both of a PDCCH which configures a PDSCH for the NES cell 92 and a PUSCH for the UE 93 to transmit data to the anchor cell 91 during the RACH procedure. The UE 93 then transmits 96 its scheduled data to the anchor cell 91 in the configured PUSCH as would usually be the case in a RACH procedure where the UE 93 is connecting to the anchor cell 91 itself. However, the key difference here is that it is the non-anchor cell 92 that transmits 97 the contention resolution message (i.e., the final message of a four-step RACH procedure) to the UE 93 in the configured PDSCH rather than the anchor cell 91, and subsequently, upon completion of the RACH procedure, the UE 93 is connected to the network via the non-anchor NES cell 92. Here, the contention resolution message is cross-scheduled by the anchor cell 91, such that the PDCCH received 95 by the anchor cell 91 configures the PDSCH received 97 from the non-anchor cell 92. Those skilled in the art would well understand the general concept of crossscheduling, for example, with respect to carrier aggregation.

[0093] Such a procedure as that illustrated by Figure 9 provides an advantage in that the NES cell is freed from a large portion of the RACH procedure, therefore optimising its energy saving performance. Such energy saving achieved by NES cells can be understood with reference to [7], particularly in section 6.1.1 (and with reference to Table 6.1.1.2-5), from which the following paragraph is reproduced.

[0094] The transmission of common signal and channels or reception of random-access signals may limit the gNB ability to use (deeper) sleep modes to save energy. Based on the results with multiple static RACH occasion configurations, one source observed that adaptation of RACH occasions can achieve BS energy savings by 14.4 % ~ 24.9 % for BS Category 1 at empty load case under FR1 TDD compared to 10ms RACH periodicity without adaptation. The gain generally increases as PRACH periodicity increases for the same number of SSBs. Performance of dynamic RACH configuration is not provided. On UPT / access delay / latency, this scheme increases access delay / latency from 10 ms to 70 ms, proportional to the increased PRACH periodicity.

[0095] Thus, having reference to [7] and particularly the above-reproduced paragraph therefrom, an NES cell can thus - when employing such solutions as proposed by arrangements of embodiments of the present technique as described above with regard to Figure 9 - be seen to have even more than the noted upper limit 24.9 % of energy saving gain because it is fully freed from monitoring (e.g. for PRACH preambles). In any case, the anchor cell needs to be the cell that monitors the PRACH for such preambles from the UEs in its coverage.

[0096] However, such solutions as proposed by arrangements of embodiments of the present technique as described above with regard to Figure 9 do impose some restrictions. For example, it is necessary that the anchor cell and NES cell need to share the same time alignment (which may be achieved in the same signalling indication transmitted by the anchor cell to the NES cell in respect of notifying it of the upcoming RACH procedure), or if not, the NES cell may need to update the timing advance of the UE after it has moved to RRC CONNECTED with the NES cell upon completion of the RACH procedure.

[0097] Another advantage of such a procedure as that illustrated by Figure 9 provides an advantage in that the anchor cell is freed a part of the RACH procedure - at least in respect of the prior art techniques described above in respect of the examples of Figures 6 and 7 - in that the contention resolution message is cross-scheduled for the NES cell, therefore improving the efficiency of operation of the anchor cell to some degree.

[0098] A similar procedure as that described above with respect to Figure 9 can be applied to the two-step RACH procedure as well. Figure 10 shows an example of how a UE may access an NES cell via an anchor cell using a two-step RACH procedure in accordance with embodiments of the present technique. Here, in the example of Figure 10, the UE 103 first transmits 104 a random access preamble to the anchor cell 101 as well as a PUSCH (which may be a pre-scheduled or semi-statically scheduled PUSCH) comprising scheduled data. In response, the UE 103 receives 105 a contention resolution message (i.e., the final message of a four-step RACH procedure) from the non-anchor NES cell 102. Here, the contention resolution message may, like in the example of Figure 9, again be cross-scheduled by the anchor cell 101.

[0099] The legacy procedures for UE access via NES cells is, such as those described above with respect to Figures 6 and 7, that the UE initiates the RACH procedure to set up such a connection via its camped cell. Furthermore, it is specified generally (e.g. in [7]) that the UE camps on an anchor cell rather than a nonanchor NES cell (without SIB / SSB). However, some arrangements of embodiments of the present technique recognise that, with some additional assistance information, a UE is able to access the NES cell directly instead. Such direct access may indeed not require the anchor cell to be involved in the RACH procedure at all, which is different to the arrangements of embodiments of the present technique as exemplified by Figures 9 and 10 as described above in which the UE only needs to perform a single RACH procedure to connect to the non-anchor NES cell, albeit that such a single RACH procedure does at least require involvement of the anchor cell.

[0100] Figure 11 shows such an example of how a UE may access an NES cell via the NES cell itself in accordance with embodiments of the present technique. Here, like for the procedures exemplified by Figures 9 and 10, in terms of preparation, before the RACH procedure itself is actually performed, the anchor cell will transmit SSB / SIBs to the UE, which may contain any necessary access information (for example, preambles, RACH resources of the non-anchor NES cell, etc.). There may further be an indication in the SIB of the anchor cell to tell the UE to initiate the RACH procedure on the NES cell itself, where the configuration of the NES cell is included in the system information. The anchor cell also needs to indicate to the non-anchor NES cell that an NES UE is going to initiate a RACH procedure to connect to the non-anchor NES cell, and therefore that the non-anchor NES cell needs to begin monitoring for PRACH preambles from such an NES UE (e.g. in specific indicated PRACH resources). In other words, the system information may comprise an indication that the communications device is to initiate the random access procedure with the second infrastructure equipment and perform the random access procedure with only the second infrastructure equipment.

[0101] As can be seen in the example of Figure 11, the UE 113 first transmits 114 a random access preamble to the non-anchor NES cell 112, and receives 115 a RAR from the non-anchor NES cell 112 in response to the transmitted 114 preamble, where such a RAR may comprise both of a PDCCH which configures a PDSCH for the NES cell 112 to transmit a contention resolution message and a PUSCH for the UE 113 to transmit data to the non-anchor cell 112 during the RACH procedure. The UE 113 then transmits 116 its scheduled data to the non-anchor NES cell 112 in the configured PUSCH, before receiving 117 the contention resolution message from the non-anchor NES cell 112 in the configured PDSCH.

[0102] While Figure 11 shows the example procedure for a four-step RACH, those skilled in the art would appreciate that arrangements of embodiments of the present technique in which the UE may access an NES cell via the NES cell itself may also be implemented using a two-step RACH procedure. That is, the UE 113 may alternatively be configured to transmit, to the non-anchor NES cell 112, a first message comprising both of a random access preamble and an uplink data transmission, and to receive, from the non-anchor NES cell 112, a second message comprising contention resolution information.

[0103] Here, an advantage of such procedures as those exemplified by Figure 11 is that the anchor cell is able to completely offload the RACH procedures for NES UEs to NES cells. This may be particularly important in situations or networks where the ratio of the number of non-anchor NES cells to anchor cells is high, and the anchor cells would otherwise each have to be responsible for involvement in RACH procedures for a relatively high number of non-anchor NES cells. However, such procedures do require that the non- anchor NES cells monitor for PRACH preambles, which therefore does increase the amount of power and energy consumption by such non-anchor NES cells, which may not be acceptable in all situations.

[0104] Figure 12 shows a flow diagram illustrating a first example process of communications in a communications system in accordance with embodiments of the present technique. The process shown by Figure 12 is specifically a method of operating a communications device (e.g., UE).

[0105] The method begins in step S 1. The method comprises, in step S2, receiving, from a first infrastructure equipment (e.g. gNB) while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to a wireless communications network via a second infrastructure equipment (e.g. gNB). Here, the first infrastructure equipment controls an anchor cell of the wireless communications network and the second infrastructure equipment controls a nonanchor cell of the wireless communications network, the non-anchor cell being a network energy saving (NES) cell. In step S3, the process comprises connecting, based on receiving the system information from the first infrastructure equipment, to the wireless communications network via the second infrastructure equipment by performing a single random access procedure. Then, in step S4, the method comprises transmitting signals to and / or receiving signals from the second infrastructure equipment after the communications device has connected to the wireless communications network via the second infrastructure equipment. The process ends in step S5.

[0106] Those skilled in the art would appreciate that the method shown by Figure 12 may be adapted in accordance with embodiments of the present technique. For example, other intermediate steps may be included in such a method, or the steps may be performed in any logical order. Though embodiments of the present technique have been described largely by way of the example communications system shown in Figure 8, and further described by way of the example access procedures illustrated by Figures 9, 10, and 11, it would be clear to those skilled in the art that they could be equally applied to other systems and procedures to those described herein.

[0107] Those skilled in the art would further appreciate that such infrastructure equipment and / or communications devices 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 and communications devices as herein defined and described may form part of communications systems other than those defined by the present disclosure.

[0108] The following numbered paragraphs provide further example aspects and features of the present technique:

[0109] Paragraph 1. A method of operating a communications device, the method comprising receiving, from a first infrastructure equipment while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to a wireless communications network via a second infrastructure equipment, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network and the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, connecting, based on receiving the system information from the first infrastructure equipment, to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and transmitting signals to and / or receiving signals from the second infrastructure equipment after the communications device has connected to the wireless communications network via the second infrastructure equipment.

[0110] Paragraph 2. A method according to Paragraph 1, wherein the system information comprises an indication of information to be used by the communications device to perform the random access procedure.

[0111] Paragraph 3. A method according to Paragraph 2, wherein the information to be used by the communications device to perform the random access procedure comprises one or more random access preambles that the communications device is able to use to initiate the random access procedure.

[0112] Paragraph 4. A method according to Paragraph 2 or Paragraph 3, wherein the information to be used by the communications device to perform the random access procedure comprises a location of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device.

[0113] Paragraph 5. A method according to any of Paragraphs 2 to 4, wherein the information to be used by the communications device to perform the random access procedure comprises a periodicity of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device.

[0114] Paragraph 6. A method according to any of Paragraphs 2 to 5, wherein the information to be used by the communications device to perform the random access procedure is specific to communications devices that are configured to connected to non-anchor NES cells.

[0115] Paragraph 7. A method according to any of Paragraphs 1 to 6, wherein the system information comprises an indication that the communications device is to initiate the random access procedure with the first infrastructure equipment and perform the random access procedure with both of the first infrastructure equipment and the second infrastructure equipment.

[0116] Paragraph 8. A method according to Paragraph 7, wherein the random access procedures comprises transmitting, to the first infrastructure equipment, a first message comprising a random access preamble, receiving, from the first infrastructure equipment, a second message comprising a random access response, the random access response comprising an indication of uplink resources to be used by the communications device for an uplink data transmission during the random access procedure, transmitting, to the first infrastructure equipment, a third message comprising the uplink data transmission in the indicated uplink resources, and receiving, from the second infrastructure equipment, a fourth message comprising contention resolution information.

[0117] Paragraph 9. A method according to Paragraph 7, wherein the random access procedures comprises transmiting, to the first infrastructure equipment, a first message comprising both of a random access preamble and an uplink data transmission, and receiving, from the second infrastructure equipment, a second message comprising contention resolution information.

[0118] Paragraph 10. A method according to any of Paragraphs 1 to 9, wherein the system information comprises an indication that the communications device is to initiate the random access procedure with the second infrastructure equipment and perform the random access procedure with only the second infrastructure equipment.

[0119] Paragraph 11. A method according to Paragraph 10, wherein the random access procedures comprises transmiting, to the second infrastructure equipment, a first message comprising a random access preamble, receiving, from the second infrastructure equipment, a second message comprising a random access response, the random access response comprising an indication of uplink resources to be used by the communications device for an uplink data transmission during the random access procedure, transmiting, to the second infrastructure equipment, a third message comprising the uplink data transmission in the indicated uplink resources, and receiving, from the second infrastructure equipment, a fourth message comprising contention resolution information.

[0120] Paragraph 12. A method according to Paragraph 10, wherein the random access procedures comprises transmiting, to the second infrastructure equipment, a first message comprising both of a random access preamble and an uplink data transmission, and receiving, from the second infrastructure equipment, a second message comprising contention resolution information.

[0121] Paragraph 13. A communications device comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first infrastructure equipment while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to a wireless communications network via a second infrastructure equipment, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network and the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, to connect, based on receiving the system information from the first infrastructure equipment, to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and to transmit signals to and / or to receive signals from the second infrastructure equipment after the communications device has connected to the wireless communications network via the second infrastructure equipment.

[0122] Paragraph 14. Circuitry for a communications device, the circuitry comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first infrastructure equipment while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to a wireless communications network via a second infrastructure equipment, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network and the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, to connect, based on receiving the system information from the first infrastructure equipment, to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and to transmit signals to and / or to receive signals from the second infrastructure equipment after the communications device has connected to the wireless communications network via the second infrastructure equipment.

[0123] Paragraph 15. A method of operating a first infrastructure equipment of a wireless communications network, the first infrastructure equipment controlling an anchor cell of the wireless communications network, the method comprising transmitting, to a communications device while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to the wireless communications network via a second infrastructure equipment, wherein the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, and wherein the system information indicates that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and transmitting, to the second infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing the random access procedure.

[0124] Paragraph 16. A method according to Paragraph 15, wherein the system information comprises an indication of information to be used by the communications device to perform the random access procedure.

[0125] Paragraph 17. A method according to Paragraph 16, wherein the information to be used by the communications device to perform the random access procedure comprises one or more random access preambles that the communications device is able to use to initiate the random access procedure.

[0126] Paragraph 18. A method according to Paragraph 16 or Paragraph 17, wherein the information to be used by the communications device to perform the random access procedure comprises a location of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device.

[0127] Paragraph 19. A method according to any of Paragraphs 16 to 18, wherein the information to be used by the communications device to perform the random access procedure comprises a periodicity of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device.

[0128] Paragraph 20. A method according to any of Paragraphs 16 to 19, wherein the information to be used by the communications device to perform the random access procedure is specific to communications devices that are configured to connected to non-anchor NES cells.

[0129] Paragraph 21. A method according to any of Paragraphs 16 to 20, wherein the information to be used by the communications device to perform the random access procedure is generated by the first infrastructure equipment.

[0130] Paragraph 22. A method according to any of Paragraphs 16 to 21, wherein the information to be used by the communications device to perform the random access procedure is received by the first infrastructure equipment from the second infrastructure equipment.

[0131] Paragraph 23. A method according to any of Paragraphs 15 to 22, wherein the system information comprises an indication that the communications device is to initiate the random access procedure with the first infrastructure equipment and perform the random access procedure with both of the first infrastructure equipment and the second infrastructure equipment.

[0132] Paragraph 24. A method according to Paragraph 23, wherein the random access procedures comprises receiving, from the communications device, a first message comprising a random access preamble, transmitting, to the communications device, a second message comprising a random access response, the random access response comprising an indication of uplink resources to be used by the communications device for an uplink data transmission during the random access procedure, receiving, from the communications device, a third message comprising the uplink data transmission in the indicated uplink resources, and determining that the communications device will receive, from the second infrastructure equipment, a fourth message comprising contention resolution information.

[0133] Paragraph 25. A method according to Paragraph 23, wherein the random access procedures comprises receiving, from the communications device, a first message comprising both of a random access preamble and an uplink data transmission, and determining that the communications device will receive, from the second infrastructure equipment, a second message comprising contention resolution information.

[0134] Paragraph 26. A method according to any of Paragraphs 15 to 25, wherein the system information comprises an indication that the communications device is to initiate the random access procedure with the second infrastructure equipment and perform the random access procedure with only the second infrastructure equipment.

[0135] Paragraph 27. A first infrastructure equipment of a wireless communications network, the first infrastructure equipment controlling an anchor cell of the wireless communications network and comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to transmit, to a communications device while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to the wireless communications network via a second infrastructure equipment, wherein the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, and wherein the system information indicates that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and to transmit, to the second infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing the random access procedure.

[0136] Paragraph 28. Circuitry for a first infrastructure equipment of a wireless communications network, the first infrastructure equipment controlling an anchor cell of the wireless communications network, the circuitry comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to transmit, to a communications device while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to the wireless communications network via a second infrastructure equipment, wherein the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, and wherein the system information indicates that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and to transmit, to the second infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing the random access procedure.

[0137] Paragraph 29. A method of operating a second infrastructure equipment of a wireless communications network, the second infrastructure equipment controlling a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, the method comprising receiving, from a first infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network, performing, with the communications device, at least part of the random access procedure, and transmitting signals to and / or receiving signals from the communications device after the communications device has connected to the wireless communications network via the second infrastructure equipment.

[0138] Paragraph 30. A method according to Paragraph 29, comprising determining that the communications device has exchanged one or more messages of the random access procedure with the first infrastructure equipment, and transmitting to the communications device, as a last message of the random access procedure, a contention resolution message.

[0139] Paragraph 31. A method according to Paragraph 29, comprising determining, based on receiving the indication from the first infrastructure equipment, that the second infrastructure equipment is to begin monitoring for random access preambles from the communications device.

[0140] Paragraph 32. A method according to Paragraph 31, wherein the random access procedures comprises receiving, from the communications device, a first message comprising a random access preamble, transmitting, to the communications device, a second message comprising a random access response, the random access response comprising an indication of uplink resources to be used by the communications device for an uplink data transmission during the random access procedure, receiving, from the communications device, a third message comprising the uplink data transmission in the indicated uplink resources, and transmitting, to the communications device, a fourth message comprising contention resolution information.

[0141] Paragraph 33. A method according to Paragraph 31, wherein the random access procedures comprises receiving, from the communications device, a first message comprising both of a random access preamble and an uplink data transmission, and transmitting, to the communications device, a second message comprising contention resolution information.

[0142] Paragraph 34. A second infrastructure equipment of a wireless communications network, the second infrastructure equipment comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network, to perform, with the communications device, at least part of the random access procedure, and to transmit signals to and / or to receive signals from the communications device after the communications device has connected to the wireless communications network via the second infrastructure equipment.

[0143] Paragraph 35. Circuitry for a second infrastructure equipment of a wireless communications network, the circuitry comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network, to perform, with the communications device, at least part of the random access procedure, and to transmit signals to and / or to receive signals from the communications device after the communications device has connected to the wireless communications network via the second infrastructure equipment.

[0144] Paragraph 36. A wireless communications system comprising a communications device according to Paragraph 13, a first infrastructure equipment according to Paragraph 27, and a second infrastructure equipment according to Paragraph 34.

[0145] Paragraph 37. A computer program comprising instructions which, when loaded onto a computer, cause the computer to perform a method according to any of Paragraphs 1 to 12, Paragraphs 15 to 26, or Paragraphs 29 to 33.

[0146] Paragraph 38. A non-transitory computer-readable storage medium storing a computer program according to Paragraph 37.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] References

[0151] [1] Holma H. and Toskala A, “LTE for UMTS OFDMA and SC-FDMA based radio access”, John Wiley and Sons, 2009.

[0152] [2] TS 38.470, “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NG-RAN; Fl general aspects and principles (Release 17)”, 3GPP, V17.4.0, March

[0153] 2023.

[0154] [3] TS 38.473, “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NG-RAN; Fl application protocol (F1AP) (Release 17)”, 3GPP, V17.4.1, April 2023.

[0155] [4] TS 38.401, “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NG-RAN; Architecture description (Release 17)”, 3GPP, V17.4.0, March 2023.

[0156] [5] RP -213554, “Study on network energy savings for NR,” (Huawei), 3GPP TSG RAN Meeting #94e, December 2021.

[0157] [6] TR 38.840, “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Study on User Equipment (UE) power saving in NR (Release 16),” 3GPP, V16.0.0, June 2019.

[0158] [7] TR 38.864, “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on network energy savings for NR (Release 18),” 3GPP, V18.1.0, March 2023.

[0159] [8] R2 -2305250, “Discussion on SSB / SIB-less Solutions for NES,” (Samsung), 3GPP TSG RAN2 Meeting #122, May 2023.

Claims

CLAIMSWhat is claimed is:

1. A method of operating a communications device, the method comprising receiving, from a first infrastructure equipment while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to a wireless communications network via a second infrastructure equipment, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network and the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, connecting, based on receiving the system information from the first infrastructure equipment, to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and transmitting signals to and / or receiving signals from the second infrastructure equipment after the communications device has connected to the wireless communications network via the second infrastructure equipment.

2. A method according to Claim 1, wherein the system information comprises an indication of information to be used by the communications device to perform the random access procedure.

3. A method according to Claim 2, wherein the information to be used by the communications device to perform the random access procedure comprises one or more random access preambles that the communications device is able to use to initiate the random access procedure.

4. A method according to Claim 2, wherein the information to be used by the communications device to perform the random access procedure comprises a location of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device.

5. A method according to Claim 2, wherein the information to be used by the communications device to perform the random access procedure comprises a periodicity of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device.

6. A method according to Claim 2, wherein the information to be used by the communications device to perform the random access procedure is specific to communications devices that are configured to connected to non-anchor NES cells.

7. A method according to Claim 1, wherein the system information comprises an indication that the communications device is to initiate the random access procedure with the first infrastructure equipment and perform the random access procedure with both of the first infrastructure equipment and the second infrastructure equipment.

8. A method according to Claim 7, wherein the random access procedures comprises transmitting, to the first infrastructure equipment, a first message comprising a random access preamble, receiving, from the first infrastructure equipment, a second message comprising a random access response, the random access response comprising an indication of uplink resources to be used by the communications device for an uplink data transmission during the random access procedure,transmitting, to the first infrastructure equipment, a third message comprising the uplink data transmission in the indicated uplink resources, and receiving, from the second infrastructure equipment, a fourth message comprising contention resolution information.

9. A method according to Claim 7, wherein the random access procedures comprises transmitting, to the first infrastructure equipment, a first message comprising both of a random access preamble and an uplink data transmission, and receiving, from the second infrastructure equipment, a second message comprising contention resolution information.

10. A method according to Claim 1, wherein the system information comprises an indication that the communications device is to initiate the random access procedure with the second infrastructure equipment and perform the random access procedure with only the second infrastructure equipment.

11. A method according to Claim 10, wherein the random access procedures comprises transmitting, to the second infrastructure equipment, a first message comprising a random access preamble, receiving, from the second infrastructure equipment, a second message comprising a random access response, the random access response comprising an indication of uplink resources to be used by the communications device for an uplink data transmission during the random access procedure, transmitting, to the second infrastructure equipment, a third message comprising the uplink data transmission in the indicated uplink resources, and receiving, from the second infrastructure equipment, a fourth message comprising contention resolution information.

12. A method according to Claim 10, wherein the random access procedures comprises transmitting, to the second infrastructure equipment, a first message comprising both of a random access preamble and an uplink data transmission, and receiving, from the second infrastructure equipment, a second message comprising contention resolution information.

13. A communications device comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first infrastructure equipment while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to a wireless communications network via a second infrastructure equipment, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network and the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, to connect, based on receiving the system information from the first infrastructure equipment, to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and to transmit signals to and / or to receive signals from the second infrastructure equipment after the communications device has connected to the wireless communications network via the second infrastructure equipment.

14. Circuitry for a communications device, the circuitry comprisingtransceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first infrastructure equipment while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to a wireless communications network via a second infrastructure equipment, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network and the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, to connect, based on receiving the system information from the first infrastructure equipment, to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and to transmit signals to and / or to receive signals from the second infrastructure equipment after the communications device has connected to the wireless communications network via the second infrastructure equipment.

15. A method of operating a first infrastructure equipment of a wireless communications network, the first infrastructure equipment controlling an anchor cell of the wireless communications network, the method comprising transmitting, to a communications device while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to the wireless communications network via a second infrastructure equipment, wherein the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, and wherein the system information indicates that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and transmitting, to the second infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing the random access procedure.

16. A method according to Claim 15, wherein the system information comprises an indication of information to be used by the communications device to perform the random access procedure.

17. A method according to Claim 16, wherein the information to be used by the communications device to perform the random access procedure comprises one or more random access preambles that the communications device is able to use to initiate the random access procedure.

18. A method according to Claim 16, wherein the information to be used by the communications device to perform the random access procedure comprises a location of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device.

19. A method according to Claim 16, wherein the information to be used by the communications device to perform the random access procedure comprises a periodicity of communications resources in which one or more messages of the random access procedure are to be transmitted and / or received by the communications device.

20. A method according to Claim 16, wherein the information to be used by the communications device to perform the random access procedure is specific to communications devices that are configured to connected to non-anchor NES cells.

21. A method according to Claim 16, wherein the information to be used by the communications device to perform the random access procedure is generated by the first infrastructure equipment.

22. A method according to Claim 16, wherein the information to be used by the communications device to perform the random access procedure is received by the first infrastructure equipment from the second infrastructure equipment.

23. A method according to Claim 15, wherein the system information comprises an indication that the communications device is to initiate the random access procedure with the first infrastructure equipment and perform the random access procedure with both of the first infrastructure equipment and the second infrastructure equipment.

24. A method according to Claim 23, wherein the random access procedures comprises receiving, from the communications device, a first message comprising a random access preamble, transmitting, to the communications device, a second message comprising a random access response, the random access response comprising an indication of uplink resources to be used by the communications device for an uplink data transmission during the random access procedure, receiving, from the communications device, a third message comprising the uplink data transmission in the indicated uplink resources, and determining that the communications device will receive, from the second infrastructure equipment, a fourth message comprising contention resolution information.

25. A method according to Claim 23, wherein the random access procedures comprises receiving, from the communications device, a first message comprising both of a random access preamble and an uplink data transmission, and determining that the communications device will receive, from the second infrastructure equipment, a second message comprising contention resolution information.

26. A method according to Claim 15, wherein the system information comprises an indication that the communications device is to initiate the random access procedure with the second infrastructure equipment and perform the random access procedure with only the second infrastructure equipment.

27. A first infrastructure equipment of a wireless communications network, the first infrastructure equipment controlling an anchor cell of the wireless communications network and comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to transmit, to a communications device while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to the wireless communications network via a second infrastructure equipment, wherein the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, and wherein the system information indicates that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and to transmit, to the second infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing the random access procedure.

28. Circuitry for a first infrastructure equipment of a wireless communications network, the first infrastructure equipment controlling an anchor cell of the wireless communications network, the circuitry comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to transmit, to a communications device while the communications device is operating in an idle mode, system information indicating that the communications device is to connect to the wireless communications network via a second infrastructure equipment, wherein the second infrastructure equipment controls a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, and wherein the system information indicates that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, and to transmit, to the second infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing the random access procedure.

29. A method of operating a second infrastructure equipment of a wireless communications network, the second infrastructure equipment controlling a non-anchor cell of the wireless communications network, the non-anchor cell being a network energy saving, NES, cell, the method comprising receiving, from a first infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network, performing, with the communications device, at least part of the random access procedure, and transmitting signals to and / or receiving signals from the communications device after the communications device has connected to the wireless communications network via the second infrastructure equipment.

30. A method according to Claim 29, comprising determining that the communications device has exchanged one or more messages of the random access procedure with the first infrastructure equipment, and transmitting to the communications device, as a last message of the random access procedure, a contention resolution message.

31. A method according to Claim 29, comprising determining, based on receiving the indication from the first infrastructure equipment, that the second infrastructure equipment is to begin monitoring for random access preambles from the communications device.

32. A method according to Claim 31, wherein the random access procedures comprises receiving, from the communications device, a first message comprising a random access preamble, transmitting, to the communications device, a second message comprising a random access response, the random access response comprising an indication of uplink resources to be used by the communications device for an uplink data transmission during the random access procedure, receiving, from the communications device, a third message comprising the uplink data transmission in the indicated uplink resources, and transmitting, to the communications device, a fourth message comprising contention resolution information.

33. A method according to Claim 31, wherein the random access procedures comprises receiving, from the communications device, a first message comprising both of a random access preamble and an uplink data transmission, and transmitting, to the communications device, a second message comprising contention resolution information.

34. A second infrastructure equipment of a wireless communications network, the second infrastructure equipment comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network, to perform, with the communications device, at least part of the random access procedure, and to transmit signals to and / or to receive signals from the communications device after the communications device has connected to the wireless communications network via the second infrastructure equipment.

35. Circuitry for a second infrastructure equipment of a wireless communications network, the circuitry comprising transceiver circuitry configured to transmit signals to and / or to receive signals, and controller circuitry configured in combination with the transceiver circuitry to receive, from a first infrastructure equipment, an indication that the communications device is to connect to the wireless communications network via the second infrastructure equipment by performing a single random access procedure, wherein the first infrastructure equipment controls an anchor cell of the wireless communications network, to perform, with the communications device, at least part of the random access procedure, and to transmit signals to and / or to receive signals from the communications device after the communications device has connected to the wireless communications network via the second infrastructure equipment.

36. A wireless communications system comprising a communications device according to Claim 13, a first infrastructure equipment according to Claim 27, and a second infrastructure equipment according to Claim 34.

37. A computer program comprising instructions which, when loaded onto a computer, cause the computer to perform a method according to Claim 1, Claim 15, or Claim 29.

38. A non-transitory computer-readable storage medium storing a computer program according to Claim 37.

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