WO2025252483A1 - Methods, communications devices, and infrastructure equipment - Google Patents

Abstract

A method of operating a communications device configured to transmit signals to and/or to receive signals from an infrastructure equipment of a wireless communications network via a radio access interface between the communications device and the infrastructure equipment is provided. Here, the communications device is a sub-band full duplex, SBFD, capable communications device. The method comprises determining that the communications device is to perform a random access procedure with the infrastructure equipment, calculating an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment as part of the random access procedure, wherein the communications device determines whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface, and transmitting the PRACH preamble to the infrastructure equipment in the at least one RO and using the calculated uplink transmission power.

Description

METHODS, COMMUNICATIONS DEVICES, AND INFRASTRUCTURE EQUIPMENT BACKGROUND Field of Disclosure The present disclosure relates to communications devices, infrastructure equipment, and methods for the more efficient and effective transmission of data in a wireless communications network. The present application claims the Paris Convention priority from European patent application number EP24180320.4, filed on 5 June 2024, the contents of which are hereby incorporated by reference. Description of Related Art The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention. 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. 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 considerations may apply for efficiently supporting data exchange with a smartphone when it is running a video streaming application (high downlink data) as compared to when it is running an Internet browsing application (sporadic uplink and downlink data) or being used for voice communications by an emergency responder in an emergency scenario (data subject to stringent reliability and latency requirements). In view of this there is expected to be a desire for 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. SUMMARY OF THE DISCLOSURE The present disclosure can help address or mitigate at least some of the issues discussed above. Embodiments of the present technique can provide a method of operating a communications device configured to transmit signals to and/or to receive signals from an infrastructure equipment of a wireless communications network via a radio access interface between the communications device and the infrastructure equipment. Here, the communications device is a sub-band full duplex, SBFD, capable communications device. The method comprises determining that the communications device is to perform a random access procedure with the infrastructure equipment, calculating an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment as part of the random access procedure, wherein the communications device determines whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface, and transmitting the PRACH preamble to the infrastructure equipment in the at least one RO and using the calculated uplink transmission power. 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 and effective transmission of uplink signals by a communications device. Respective aspects and features of the present disclosure are defined in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the present technology. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein like reference numerals designate identical or corresponding parts throughout the several views, and wherein: Figure 1 schematically represents some aspects of an LTE-type wireless telecommunication system which may be configured to operate in accordance with certain embodiments of the present disclosure; Figure 2 schematically represents some aspects of a new radio access technology (RAT) wireless telecommunications system which may be configured to operate in accordance with certain embodiments of the present disclosure; Figure 3 is a schematic block diagram of an example infrastructure equipment and communications device which may be configured to operate in accordance with certain embodiments of the present disclosure; Figure 4 schematically represents a first example of non-overlapping sub-bands for uplink and downlink transmissions for sub-band full duplex (SBFD); Figure 5 schematically represents second and third examples of non-overlapping sub-bands for uplink and downlink transmissions for SBFD; Figure 6 schematically illustrates the components of a synchronisation signal block (SSB); Figure 7 schematically illustrates an SSB burst set transmitted on SSB beams; Figure 8 schematically illustrates a physical random access channel (PRACH) occasion (RO) configuration; Figures 9A to 9D schematically illustrates valid and invalid ROs; Figure 10 schematically illustrates an example of a time division duplexing (TDD) slot format configuration; Figure 11 schematically illustrates an example of an SSB to RO mapping in an association period for a TDD slot format; Figure 12 schematically illustrates an example of a set of N_PRACH = 4 ROs for 4 x PRACH repetitions; Figure 13 schematically illustrates an example of an overall SSB-RO association using a single PRACH configuration; Figure 14 schematically illustrates an example of an SBFD RO configuration on a separate PRACH configuration; Figure 15 schematically illustrates an example of PRACH repetitions using SBFD ROs and non-SBFD ROs in accordance with certain embodiments of the present disclosure; Figure 16 shows a part schematic, part message flow diagram representation of an example wireless communications system comprising a communications device and an infrastructure equipment in accordance with embodiments of the present technique; and Figure 17 shows a flow diagram illustrating an example process of communications in a communications system in accordance with embodiments of the present technique. DETAILED DESCRIPTION OF THE EMBODIMENTS Long Term Evolution Advanced Radio Access Technology (4G) Figure 1 provides a schematic diagram illustrating some basic functionality of a mobile telecommunications network / system 6 operating generally in accordance with LTE principles, but which may also support other radio access technologies, and which may be adapted to implement embodiments of the disclosure as described herein. Various elements of Figure 1 and certain aspects of their respective modes of operation are well-known and defined in the relevant standards administered by the 3GPP (RTM) body, and also described in many books on the subject, for example, Holma H. and Toskala A [1]. It will be appreciated that operational aspects of the telecommunications networks discussed herein which are not specifically described (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be implemented in accordance with any known techniques, for example according to the relevant standards and known proposed modifications and additions to the relevant standards. The network 6 includes a plurality of base stations 1 connected to a core network 2. Each base station provides a coverage area 3 (i.e. a cell) within which data can be communicated to and from communications devices 4. Although each base station 1 is shown in Figure 1 as a single entity, the skilled person will appreciate that some of the functions of the base station may be carried out by disparate, inter-connected elements, such as antennas (or antennae), remote radio heads, amplifiers, etc. Collectively, one or more base stations may form a radio access network. Data is transmitted from base stations 1 to communications devices 4 within their respective coverage areas 3 via a radio downlink (DL). Data is transmitted from communications devices 4 to the base stations 1 via a radio uplink (UL). The core network 2 routes data to and from the communications devices 4 via the respective base stations 1 and provides functions such as authentication, mobility management, charging and so on. Communications devices may also be referred to as mobile stations, user equipment (UEs), user terminals, mobile radios, mobile terminals, terminal devices, wireless transmit and receive units (WTRUs), and so forth. Services provided by the core network 2 may include connectivity to the internet or to external telephony services. The core network 2 may further track the location of the communications devices 4 so that it can efficiently contact (i.e. page) the communications devices 4 for transmitting downlink data towards the communications devices 4. Base stations, which are an example of network infrastructure equipment, may also be referred to as transceiver stations, nodeBs, e-nodeBs, eNB, g-nodeBs, gNB and so forth. In this regard different terminology is often associated with different generations of wireless telecommunications systems for elements providing broadly comparable functionality. However, certain embodiments of the disclosure may be equally implemented in different generations of wireless telecommunications systems, and for simplicity certain terminology may be used regardless of the underlying network architecture. That is to say, the use of a specific term in relation to certain example implementations is not intended to indicate these implementations are limited to a certain generation of network that may be most associated with that particular terminology. New Radio Access Technology (5G) Systems incorporating NR technology are expected to support different services (or types of services), which may be characterised by different requirements for latency, data rate and/or reliability. For example, Enhanced Mobile Broadband (eMBB) services are characterised by high capacity with a requirement to support up to 20 Gb/s. The requirements for Ultra Reliable and Low Latency Communications (URLLC) services are for one transmission of a 32 byte packet to be transmitted from the radio protocol layer 2/3 SDU ingress point to the radio protocol layer 2/3 SDU egress point of the radio interface within 1 ms with a reliability of 1 – 10^-5 (99.999 %) or higher (99.9999%) [2]. Massive Machine Type Communications (mMTC) is another example of a service which may be supported by NR-based communications networks. In addition, systems may be expected to support further enhancements related to Industrial Internet of Things (IIoT) in order to support services with new requirements of high availability, high reliability, low latency, and in some cases, high-accuracy positioning. 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 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 25. The elements of the wireless access network shown in Figure 2 may operate in a similar way to corresponding elements of an LTE network as described with regard to the example of Figure 1. It will be appreciated that operational aspects of the telecommunications network represented in Figure 2, and of other networks discussed herein in accordance with embodiments of the disclosure, which are not specifically described (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be implemented in accordance with any known techniques, for example according to currently used approaches for implementing such operational aspects of wireless telecommunications systems, e.g. in accordance with the relevant standards. The TRPs 10 of Figure 2 may in part have a corresponding functionality to a base station or eNodeB of an LTE network. Similarly, the communications devices 14 may have a functionality corresponding to the UE devices 4 known for operation with an LTE network. It will be appreciated therefore that operational aspects of a new RAT network (for example in relation to specific communication protocols and physical channels for communicating between different elements) may be different to those known from LTE or other known mobile telecommunications standards. However, it will also be appreciated that each of the core network component, base stations and communications devices of a new RAT network will be functionally similar to, respectively, the core network component, base stations and communications devices of an LTE wireless communications network. In terms of broad top-level functionality, the core network 20 connected to the new RAT telecommunications system represented in Figure 2 may be broadly considered to correspond with the core network 2 represented in Figure 1, and the respective central units 40 and their associated distributed units / TRPs 10 may be broadly considered to provide functionality corresponding to the base stations 1 of Figure 1. The term network infrastructure equipment / access node may be used to encompass these elements and more conventional base station type elements of wireless telecommunications systems. Depending on the application at hand the responsibility for scheduling transmissions which are scheduled on the radio interface between the respective distributed units and the communications devices may lie with the controlling node / central unit and / or the distributed units / TRPs. A communications device 14 is represented in Figure 2 within the coverage area of the first communication cell 12. This communications device 14 may thus exchange signalling with the first central unit 40 in the first communication cell 12 via one of the distributed units / TRPs 10 associated with the first communication cell 12. It will further be appreciated that Figure 2 represents merely one example of a proposed architecture for a new RAT based telecommunications system in which approaches in accordance with the principles described herein may be adopted, and the functionality disclosed herein may also be applied in respect of wireless telecommunications systems having different architectures. Thus, certain embodiments of the disclosure as discussed herein may be implemented in wireless telecommunication systems / networks according to various different architectures, such as the example architectures shown in Figures 1 and 2. It will thus be appreciated the specific wireless telecommunications architecture in any given implementation is not of primary significance to the principles described herein. In this regard, certain embodiments of the disclosure may be described generally in the context of communications between network infrastructure equipment / access nodes and a communications device, wherein the specific nature of the network infrastructure equipment / access node and the communications device will depend on the network infrastructure for the implementation at hand. For example, in some scenarios the network infrastructure equipment / access node may comprise a base station, such as an LTE-type base station 1 as shown in Figure 1 which is adapted to provide functionality in accordance with the principles described herein, and in other examples the network infrastructure equipment may comprise a control unit / controlling node 40 and / or a TRP 10 of the kind shown in Figure 2 which is adapted to provide functionality in accordance with the principles described herein. A more detailed diagram of some of the components of the network shown in Figure 2 is provided by Figure 3. In Figure 3, a TRP 10 as shown in Figure 2 comprises, as a simplified representation, a wireless transmitter 30, a wireless receiver 32 and a controller or controlling processor 34 which may operate to control the transmitter 30 and the wireless receiver 32 to transmit and receive radio signals to one or more UEs 14 within a cell 12 formed by the TRP 10. As shown in Figure 3, an example UE 14 is shown to include a corresponding transmitter 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. 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. 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. The interface 46 between the DU 42 and the CU 40 is known as the F1 interface which can be a physical or a logical interface. The F1 interface 46 between CU and DU may operate in accordance with specifications 3GPP TS 38.470 and 3GPP TS 38.473, and may be formed from a fibre optic or other wired or wireless high bandwidth connection. In one example the connection 16 from the TRP 10 to the DU 42 is via fibre optic. The connection between a TRP 10 and the core network 20 can be generally referred to as a backhaul, which comprises the interface 16 from the network interface 50 of the TRP 10 to the DU 42 and the F1 interface 46 from the DU 42 to the CU 40. In order for a UE such as UE 4 or 14 to transmit uplink data to the network (e.g. on a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH)) to, for example, base station 1 or TRP 10, the UE must first ensure it is synchronised with the network on the uplink. Since a particular eNB or gNB expects to be receiving communications from many UEs, it needs to ensure that it shares a common timing understanding with each of these UEs (i.e. they are synchronised in terms of the starting times of frames and Orthogonal Frequency Division Multiplexing (OFDM) symbols). This is so that the eNB is able to schedule communication with each of them in a manner that avoids collisions and to ensure orthogonality of the uplink signals, such that inter-subcarrier interference is avoided or mitigated. Although reference is made to 5G networks, the discussions in this specification apply equally to 6G networks (and beyond) where there is expected to be significantly higher throughput, lower latency and higher reliability utilising sub-THz frequencies. Full Duplex Time Division Duplex (FD-TDD) NR/5G networks can operate using Time Division Duplex (TDD), where an entire frequency band or carrier is switched to either downlink or uplink transmissions for a time period and can be switched to the other of downlink or uplink transmissions at a later time period. Currently, TDD operates in Half Duplex mode (HD-TDD) where the gNB or UE can, at a given time, either transmit or receive packets, but not both at the same time. As wireless networks transition from NR to 5G-Advanced networks, a proposed new feature of such networks is to enhance duplexing operation for Time Division Duplex (TDD) by enabling Full Duplex operation in TDD (FD-TDD) [3], [4]. In FD-TDD, a gNB can transmit and receive data to and from the UEs at the same time on the same frequency band. In addition, a UE can operate either in HD-TDD or FD-TDD mode, depending on its capability. For example, when UEs are only capable of supporting HD-TDD, FD-TDD is achieved at the gNB by scheduling a DL transmission to a first UE and scheduling an UL transmission from a second UE within the same OFDM symbol (i.e. at the same time). Conversely, when UEs are capable of supporting FD-TDD, FD-TDD is achieved both at the gNB and the UE, where the gNB can simultaneously schedule this UE with DL and UL transmissions within the same OFDM symbol by scheduling the DL and UL transmissions at different frequencies (e.g. physical resource blocks (PRBs)) of the system bandwidth. A UE supporting FD-TDD requires more complex hardware than a UE that only supports HD-TDD. Development of current 5G networks is focused primarily on enabling FD-TDD at the gNB with UEs operating in HD-TDD mode. Motivations for enhancing duplexing operation for TDD include an improvement in system capacity, reduced latency, and improved uplink coverage. For example, in current HD-TDD systems, OFDM symbols are allocated only for either a DL or UL direction in a semi-static manner. Hence, if one direction experiences less or no data, the spare resources cannot be used in the other direction, or are, at best, under-utilised. However, if resources can be used for DL data and UL data (as in FD-TDD) at the same time, the resource utilisation in the system can be improved. Furthermore, in current HD-TDD systems, a UE can receive DL data, but cannot transmit UL data at the same time, which causes delays. If a gNB or UE is allowed to transmit and receive data at the same time (as with FD-TDD), the traffic latency will be improved. In addition, UEs are usually coverage limited in their UL transmissions when located close to the edge of a cell. While the UE coverage at the cell-edge can be improved if more time domain resources are assigned to UL transmissions (e.g. repetitions), for HD-TDD systems, if the UL direction is assigned more time resources, fewer time resources can be assigned to the DL direction, which can lead to system imbalance. In contrast, in FD-TDD, continuous UL resources can be assigned for repetition opportunities whilst allowing DL traffic to occur in those resources, thereby UL enhancing coverage without causing system imbalance. A Rel-19 Work Item (WI) [5] on Duplex Evolution is therefore agreed to specify the requirements for FD-TDD. In Rel-19 Duplex Evolution, FD-TDD is performed at the gNB, where the gNB can transmit and receive data/signals to/from the UEs at the same time on the same frequency band, whilst the UE is maintained as HD-TDD. That is, full duplex TDD is achieved at the gNB by scheduling a UE in the DL and scheduling another UE in the UL within the same OFDM symbol. One of the objectives of the Rel- 19 Duplex Evolution WI [5] is to support RACH operation in Sub-band Full Duplex (SBFD) OFDM symbols. Sub-band Full Duplex (SBFD) In SBFD, the frequency resource of a TDD system bandwidth or Bandwidth Part (BWP) (i.e. at the UE/gNB) is divided into two or more non-overlapping sub-bands, where each sub-band can be DL or UL [6]. Guard sub-bands may be used between DL and UL sub-bands to reduce inter sub-band interference. In the current 5G system, only one UL sub-band can be configured in an OFDM symbol. An example is shown in Figure 4, where simultaneous DL and UL transmissions occur in three different non-overlapping sub-bands 61 to 63, i.e. in different sets of frequency Resource Blocks (RB): Sub- band#161, Sub-band#262, Sub-band#363. The example of Figure 4 is referred to as {DUD}, because two sub-bands, Sub-band#161 and Sub-band#363, are used for DL transmissions whilst one sub-band, Sub-band#262, is used for UL transmissions. To reduce leakage from one sub-band 61 to 63 to another, a guard sub-band 64 may be configured between UL and DL sub-bands 61 to 63. Guard sub-bands 64 are configured between DL Sub-band#363 and UL Sub-band#262 and between UL Sub-band#262 and DL Sub-band#161. Figure 5 shows two further examples with a DL and UL sub-band separated by a guard sub-band, where here, the UL sub-band can be configured to occupy the lower frequency portion of the BWP whilst the DL sub-band occupies higher frequency portion of the BWP {UD} or the UL sub-band occupies the higher frequency portion of the BWP whilst the DL sub-band occupies lower frequency portion of the BWP {DU}. Here, on the left-side of Figure 5, an UL sub-band#171 is separated from a DL sub-band#2 73 by a guard sub-band 72 – this sub-band arrangement is referred to as {UD}. In this case, the DL sub- band#273 occupies a higher frequency portion of the system bandwidth than the UL sub-band#171. On the right-side of Figure 5, a DL sub-band#181 is separated from an UL sub-band#283 by a guard sub- band 82 – this sub-band arrangement is referred to as {DU}. In this case, the UL sub-band#283 occupies a higher frequency portion of the system bandwidth than the DL sub-band#181. While Figures 4 and 5 show the system bandwidth as being divided into either two or three sub-bands, those skilled in the art would appreciate that the concept of SBFD may (in further releases of the 3GPP specifications, for example) be extended such that any number of sub-bands could be used, if deemed beneficial. For example, the system bandwidth may be divided into four sub-bands, which may, using the example of Figure 4, include the two downlink sub-bands 61, 63, the uplink sub-band 62 and another uplink sub-band, though other sub-band arrangements are envisioned. Guard sub-bands may be used in substantially any sub-band arrangement. Synchronisation Signal Block As will be known to one skilled in the art, the Synchronisation Signal Block (SSB) is used for initial access and cell reselection. An example of an SSB is schematically illustrated in Figure 6. As shown in Figure 6, the SSB comprises of a Primary Synchronisation Signal (PSS), a Secondary Synchronisation Signal (SSS) and a Physical Broadcast Channel (PBCH). The SSB comprises information for a communications device, such as a UE, to detect, measure and access a cell. The SSB shown in Figure 6 comprises four OFDM symbols and 240 subcarriers. The PSS and SSS each occupy 127 subcarriers. The PBCH occupies two OFDM symbols of 240 subcarriers and also two blocks of 48 subcarriers at the top and bottom of the SSS. The SSB may be configured with a periodicity, P_SSB, of between 5 ms and 160 ms. An SSB burst set comprises a set of one or more time-multiplexed SSBs. Each SSB is transmitted in a burst set using a different downlink beam, thereby enabling beam sweeping to be implemented for SSB. An SSB burst set may be confined within 5 ms and may comprise up to 4, 8 and 64 SSBs for frequency bands below 3 GHz, between 3 GHz – 6 GHz and for FR2 respectively. As will be understood by one skilled in the art, SSB burst sets may be periodically transmitted. An example SSB burst set in the case of 3 GHz – 6 GHz frequency is shown in Figure 7. The SSB burst set shown in Figure 7 comprises eight SSBs labelled as SSB#1, SSB#2, SSB#3, SSB#4, SSB#5, SSB#6, SSB#7 and SSB#8 respectively. Each of the SSBs in the burst set is transmitted using a different downlink beam. In this example, two SSBs are configured per slot within four slots. Furthermore, the burst set is transmitted with a periodicity, P_SSB, of 20 ms. Although not shown in Figure 7, the SSB burst set is transmitted by infrastructure equipment of a wireless communications network (such as a gNB) and received by a communications device (such as a UE). The UE measures a signal quality of each SSB in the SSB burst set. The UE may then select one of the downlink beams based on the measured signal quality. For example, the UE may select the downlink beam with the highest measured signal quality provided that the measure signal quality is above a threshold (such as RSRP threshold). Then, the UE determines an uplink beam corresponding to the downlink beam to use for synchronisation with the infrastructure equipment. As will be appreciated by one skilled in the art, corresponding uplink and downlink beams form beam pairs which overlap. Therefore, the measurements of the signal quality of a downlink beam are an indication of the signal quality of the corresponding uplink beam in the beam pair. In initial access, the UE transmits RACH on the determined uplink beam. In one example, the measured signal quality of an SSB is an RSRP of the SSB. The UE may measure the RSRP of each SSB in the SSB burst set and select the downlink beam on which the SSB with the highest RSRP was transmitted provided this measured RSRP is above a threshold (such as rsrp-ThresholdSSB). Then, the UE transmits its RACH using the corresponding uplink beam. The measurement of the RSRP of an SSB may be referred to as “SS-RSRP”. The measurement of the RSRP of an SSB may comprise measuring the RSRP on resource elements where SSS is transmitted. Alternatively, or in addition, the measurement of the RSRP of an SSB may comprise measuring the RSRP on resource elements where PBCH Demodulation Reference Signals (DMRS) are transmitted. In other examples, the measured signal quality of an SSB may be a Reference Signal Received Quality (SS-RSRQ) of the SSB. The SS-RSRQ is defined as the ratio of N x SS-RSRP / RSSI (Received Signal Strength Indicator), where N is the number of resource blocks. For example, the RSSI in NR is measured in one or more OFDM symbols in a SS/PBCH Block Measurement Time Configuration (SMTC). The SMTC is a configuration to the UE to set time window for measurement by using SSB. The OFDM symbols used for RSSI measurement can be configured by higher layers. PRACH Occasions As will be understood by a person skilled in the art, a Physical Random Access (PRACH) configuration comprises a plurality of PRACH Occasions (RO) configured in uplink communications resources of a wireless access interface. The ROs in a PRACH configuration may be periodically repeating. The ROs represent transmission opportunities for a UE to transmit a PRACH. Each RO may be configured to support up to 64 preambles. In this case, each RO may support a PRACH transmission of up to 64 UEs if each UE uses a different preamble for its PRACH transmission. The ROs may be Frequency Division Multiplexed (FDM) where infrastructure equipment of a wireless communications network can configure {1, 2, 4, 8} FDM ROs for UEs. As mentioned above, ROs are configured in communications resources of a wireless access interface. Communications resources are comprised of time resources and frequency resources. The time resources of the ROs in a PRACH Occasion configuration are determined by a “PRACH Configuration Index”, which is an index to Tables 6.3.3.2-2, 6.3.3.2-3 and 6.3.3.2-4 in [7], which is hereby incorporated by reference in its entirety. There are 256, 263 and 256 PRACH configurations for FR1 FDD, FR1 TDD and FR2 respectively. The PRACH configuration index indicates a PRACH preamble format, a PRACH periodicity (known as a “PRACH Configuration Period”), a number of PRACH Occasions within a PRACH period, the starting symbol of the PRACH Occasion in a slot, and a duration of the PRACH Occasion. An example PRACH Occasion configuration for an FR1 FDD system is shown Figure 8. The PRACH Occasion is configured with FDM = 2 and with a PRACH Configuration Index = 184. The time resources of the ROs in the PRACH Occasion can be obtained from Table 6.3.3.2-2 of [7]: The PRACH Configuration Period = 20 ms since an RO occurs in every even numbered system frame number (SFN) (x = 2 and y = 0). In each even numbered SFN, subframe 4 and 9 contain a slot with ROs, i.e., PRACH slot. In this example a 15 kHz subcarrier spacing is assumed and so each subframe which is 1 ms contains 1 slot. In each PRACH slot (i.e. in subframe 4 and 9), there are seven sets of time domain ROs where each RO is two OFDM symbols long. Since FDM = 2, each time domain RO has two ROs, and this gives 14 ROs in a PRACH slot as shown in Figure 8. There are therefore 28 ROs in a PRACH Configuration Period of 20 ms (2 PRACH slots in 20ms × 7 time domain ROs × 2 FDM = 28 ROs). SSB to PRACH Occasion Association A UE may select an SSB received on a DL beam and transmit a PRACH using a corresponding UL beam. The gNB needs to know which SSB the UE has selected so that it can transmit a Random Access Response (RAR) to the UE using the same SSB beam selected by the UE, or a beam derived from the UE selected SSB beam. Since the UE uses an UL beam, the gNB may maximise its reception by tuning its receiver panels towards the direction of the UL beam. Since ROs and SSBs are configured independently, an SSB-RO association is used for the gNB to determine the UE selected SSB, so that the gNB can determine the SSB selected by the UE based on the RO and preamble used for the UE’s PRACH transmission. In SSB-RO association, each SSB is associated with one or more ROs and preambles. Infrastructure equipment of a wireless communications network (such as a gNB) transmits an indication of a number of SSBs associated with each RO and a number of preambles associated with each SSB. For example, the infrastructure equipment may transmit the following RRC parameter to the UE: ssb-perRACH- OccasionAndCB-PreamblesPerSSB. The values for SSB to RO association may be {1/8, 1/4, 1/2, 1, 2, 4, 8, 16}. In other words, SSB may be associated with 8, 4, 2 or 1 ROs, and an RO may be associated with 2, 4, 8 or 16 SSBs. In each RO, the SSB may be configured to associate with a subset of the 64 preambles or all of the 64 preambles. For the case where an RO is associated with 2, 4, 8 or 16 SSBs, each SSB may only be associated with a subset of the preambles in an RO. For example, if an RO is associated with two SSBs, then each SSB can occupy at most 32 preambles in that RO. For the case where an SSB is associated with one or more ROs, the SSB can occupy all of the 64 preambles although it can be configured to occupy fewer than 64 preambles. Once the SSB parameters, RO parameters and SSB-RO association parameters are configured, the UE may then perform the following steps in sequential order: 1. Valid ROs determination; 2. Indexing the valid ROs; and 3. Perform SSB-RO mapping. Valid ROs Determination For FDD all configured ROs are valid. However, for TDD, the following three legacy validity conditions must be met for an RO to be valid: ^ A valid RO is contained fully in UL OFDM symbols since PRACH cannot be transmitted in DL OFDM symbols; ^ In addition to being fully contained in UL OFDM symbols, there also needs to be a gap of N_gap OFDM symbols between the end of an SSB and the start of the valid RO. The value of N_gap depends on the subcarrier spacing of the PRACH and it is defined in [8], the contents of which are hereby incorporated by reference in their entirety; and ^ If an RO and an SSB falls within a PRACH slot, the RO is invalid if it precedes the SSB. Examples of valid and invalid ROs are shown in Figures 9A to 9D. The valid RO shown in Figure 9A meets all three validity conditions as detailed above. However, the invalid ROs as shown in Figures 9B, 9C, and 9D each fail to meet one of these validity conditions. The RO of Figure 9B is invalid because it falls within DL OFDM symbols. The RO of Figure 9C is invalid because there is an insufficient gap between the SSB and the RO. The RO of Figure 9D is invalid because the RO precedes the SSB within the PRACH slot. RO Indexing Once the valid ROs are determined, they are indexed in the following order: 1. First, in increasing order of preamble indexes within a single RO; 2. Second, in increasing order of frequency resource indexes for frequency multiplexed RO; 3. Third, in increasing order of time resource indexes for time multiplexed PRACH occasions within a PRACH slot; and 4. Fourth, in increasing order of indexes for PRACH slots. SSB-RO Mapping The SSBs are then mapped to the indexed ROs sequentially by RO index. This mapping is repeated every “SSB-RO Association Period”. The SSB-RO association period is the smallest integer number of PRACH Configuration Periods required for all the SSBs in an SSB burst set to fully map to RO(s) at least once. In an SSB-RO association period, if any remaining ROs cannot fully map all the SSBs of an SSB burst set, they are invalid ROs and are not used for PRACH transmissions. The allowed SSB-RO association periods for each PRACH Configuration Period are listed in Table 8.1-1 of [8], which is reproduced below as Table I. Table I: PRACH Configuration Period and SSB-RO association period (reproduced from [8]) SSB-RO association period (number of PRACH configuration period (ms) An example of an SSB to RO mapping for an SSB-RO association period will now be explained. Figure 10 illustrates a legacy TDD slot format {DDDDU}, consisting of four DL slots followed by an UL slot as shown in Figure 10, and operating in 15 kHz subcarrier spacing. SSB and PRACH are configured as follows: ^ SSB burst set has 5 SSBs {SSB#1, SSB#2, SSB#3, SSB#4, SSB#5}; ^ SSB per RO = 1/2; i.e., each SSB is mapped to two ROs; ^ Preambles per SSB = 64, i.e., all preambles in an RO are fully mapped to an SSB; ^ FDM RO = 2; and ^ PRACH Configuration Index = 129 for FR1 TDD. Using the lookup table in Table 6.3.3.2-3 of [7], the time resource configuration for PRACH Configuration Index = 129 has a PRACH Configuration Period = 10 ms. This is shown in Table II below, which reproduces a portion of this lookup table in Table 6.3.3.2-3 of [7]. Table II: PRACH Configuration Index 129 (reproduced from [7]) H C n Figure 11 shows an example of SSB to RO mapping in an association period for the legacy TDD slot format, corresponding to PRACH configuration index 129 as shown in Table II above. Here, in each PRACH Configuration Period, Subframe 3, 4, 8 and 9 contain PRACH slots, and in each PRACH slot, there are two time domain ROs with duration six OFDM symbols each, which leads to 16 ROs in a PRACH Configuration Period (four PRACH slots × two time domain ROs per PRACH slot × two FDM ROs). Since a valid RO can only reside in UL OFDM symbols, only subframes 4 and 9 have valid ROs, and the ROs in subframes 3 and 8 are invalid ROs. Hence, each PRACH Configuration Period has eight valid ROs. For a PRACH Configuration Period = 10 ms, referring to Table I as reproduced above (i.e., from Table 8.1-1 of [8]), the required SSB-RO association Period to fully map all five SSBs with SSB per RACH = 1/2 is 2 × PRACH Configuration period (20 ms), giving 2 × 8 = 16 valid ROs. The 16 valid ROs in the 20 ms SSB-RO association period are indexed firstly by preamble, secondly by frequency, thirdly by time, and lastly by PRACH slot as shown in Figure 11. The SSBs are then mapped to the indexed ROs sequentially; e.g., since SSB per RO = 1/2, SSB#1 is mapped to RO#1 and RO#2, followed by SSB#2 being mapped to RO#3 and RO#4, etc. The five SSBs are fully mapped to the ROs once in the SSB-RO association period, leaving six remaining ROs: RO#11, RO#12, RO#13, RO#14, RO#15 and RO#16 that cannot fully map to another set of five SSBs. Hence these six remaining ROs are Invalid ROs, and are not used for PRACH transmissions. PRACH Repetitions The concept of using PRACH repetitions is introduced in Rel-18 to enhance the uplink coverage of PRACH. The PRACH repetition factor is N_PRACH = {2, 4, 8}, where the PRACH is transmitted multiple times in different ROs using the same transmission beam and the same preamble. The set of ROs used for a specific PRACH repetition N_PRACH consists of valid ROs that are associated with one SSB (i.e., the selected SSB) and uses the same frequency resources. Figure 12 is an example of a set of N_PRACH ROs for a PRACH repetition of four, i.e. N_PRACH = 4, using the PRACH configurations as described in Figure 11. Figure 12 shows four SSB-RO association periods (each lasting 20 ms), spanning eight radio frames from SFN k to SFN k + 7, where in each SSB-RO association period, the five SSBs are mapped to ten ROs. Assuming the UE selected SSB#2, and requires 4 × PRACH repetitions, it has a choice between two sets of N_PRACH=4 ROs, i.e. one that starts with RO#3 (the lower frequency RO) in SFN k and another that starts with RO#4 (the higher frequency RO) in SFN k. Here, the UE selects RO#3 in SFN k as the start of the PRACH repetition. The remaining ROs in the set of N_PRACH=4 ROs are associated with the same SSB#2 and located in the same frequency; that is, the set of N_PRACH =4 ROs are RO#3 in SFN k, SFN k + 2, SFN k + 4 and SFN k + 6, which are outlined in dashed boxes in the example of Figure 12. The first set of N_PRACH ROs starts from SFN 0 and there may be a gap of TimeOffsetBetweenStartingRO valid ROs between each set of N_PRACH ROs. The value of TimeOffsetBetweenStartingRO is configured by the network. SBFD ROs In the current system, there are two methods to configure ROs for SBFD (i.e. ROs that can be configured in SBFD sub-bands and hence are usable by SBFD-capable UEs), which are also described in co-pending European patent application number EP24155834.5 [9], the contents of which are hereby incorporated by reference. That is: ^ Single PRACH Configuration: SBFD ROs and legacy ROs are configured in a single PRACH configuration; and ^ Additional PRACH Configurations: SBFD ROs and legacy ROs are configured in separate PRACH configurations, i.e., an additional/separate PRACH configuration is used for SBFD ROs. For each of these SBFD RO configuration methods, SBFD UEs will need to perform the SSB-RO association twice, where the first of these is performed on valid ROs that are validated using legacy RO validation rules, and the second SSB-RO association for SBFD RO is performed using new RO validation rules. Such new RO validation rules for SBFD RO are introduced, where an RO is valid if it resides fully within an UL sub-band and does not overlap with SSB. The SSB-RO association for SBFD RO has not yet been specified, but a potential overall SSB-RO association is shown in Figure 13, where the example PRACH configuration as used in the example in Figure 11 is used again here (i.e. corresponding to PRACH configuration index 129 as shown in Table II). Here, an {XXXXU} SBFD slot format is assumed, where “X” is a slot consisting of SBFD OFDM symbols, where in the example in Figure 13, the SBFD slots consists of a {DUD} sub-band arrangement in the frequency domain such as that shown in Figure 4. In the example of Figure 13, the UE performs an SSB-RO association using legacy RO validation rules for non-SBFD OFDM symbols, where it maps SSB#1 and SSB#2 to RO#1 and RO#2, and RO#3 and RO#4 respectively in Subframe 4 of SFN k, SSB#3 and SSB#4 to RO#5 and RO#6, and RO#7 and RO#8 respectively in Subframe 9 of SFN k, and SSB#5 to RO#9 and RO#10 in Subframe 4 of SFN k + 1. The UE performs a second SSB-RO association on SBFD OFDM symbols, where it maps SSB#1 and SSB#2 to RO#1 and RO#2, and RO#3 and RO#4 respectively in Subframe 3 of SFN k, SSB#3 and SSB#4 to RO#5 and RO#6, and RO#7 and RO#8 respectively in Subframe 8 of SFN k, and SSB#5 to RO#9 and RO#10 in Subframe 3 of SFN k + 1. The overall SSB-RO association combining the two SSB-RO associations is shown in Figure 13. Table III below shows the parameters for an example SBFD RO using a separate PRACH configuration, i.e. the SBFD UE is configured with two PRACH configurations. Table III: Dual PRACH configurations for legacy TDD and SBFD RACH Parameters Le ac TDD PRACH SBFD RACH Here the SBFD UE also performs two SSB-RO association with different RO validations but on different PRACH configurations, where a first SSB-RO association using legacy RO validation rules on the legacy PRACH configuration (PRACH Configuration Index = 127) and another SSB-RO association using the new SBFD RO validation rules on the additional PRACH configuration with PRACH Configuration Index = 125, as shown in Table IV below. The resultant SSB-RO mapping is shown in Figure 14, where the SBFD ROs occupies different frequency resources from the legacy TDD ROs. Table IV: PRACH Configuration Indices 125 and 127 (reproduced from [7]) H C n , PRACH Power Control Open loop power control is used for PRACH transmission, where the PRACH transmit power P_PRACH in dBm is determined, as defined in [8], using equation (1) below: P_PRACH = min{P_CMAX, P_PRACH,target + PL} (1) Where P_CMAX is the UE configured maximum transmit power, and P_PRACH,target is the PRACH target reception power at the gNB receiver. P_CMAX and P_PRACH,target are configured by higher layers. PL is the pathloss in dB, and it is calculated using equation (2) below: PL = referenceSignalPower – higher layer filtered RSRP (2) Here, referenceSignalPower is the transmission power of the reference signal (RS), such as SSB, and it is indicated in the SIBs. The higher layer filtered RSRP is the UE measured and filtered power of the RS, e.g. SSB. For PRACH repetitions, the PRACH power is calculated using the same method as described above, and this single calculated PRACH power is applied to all the PRACH repetitions. That is, the UE does not change its PRACH transmit power P_PRACH between PRACH repetitions, but rather transmits each repetition with the same power. Technical Issue PRACH repetition for SBFD is currently being considered in 3GPP. The benefit of introducing SBFD RO is that it increases the number of RO for RACH access and for the case of PRACH repetition, it may enable a PRACH repetition of N_PRACH to complete faster. Figure 15 shows two association periods of the SSB-RO mapping for PRACH configuration used in the example in Figure 13, where the SBFD RO and legacy TDD RO are configured on a single PRACH configuration. For a legacy TDD UE, it can only use the RO in UL slot, i.e. in Subframe 4 or Subframe 9 in each SFN, and hence for the example shown in Figure 15, a legacy TDD UE can only transmit 2 × PRACH repetitions within the two association periods or 40 ms (from SFN k to SFN k + 3). For example, if the legacy UE selects SSB#2, it will start its PRACH repetition using RO#3 in Subframe 4 of SFN k, followed by a second PRACH repetition in RO#3 in Subframe 4 of SFN k + 2, thereby achieving 2 × PRACH repetitions within two association periods (40 ms). In contrast, if an SBFD UE selects SSB#4 (or any SSB), it may start its PRACH repetitions in RO#8 in Subframe 8 (an SBFD slot) of SFN k, followed by the second, third and fourth PRACH repetitions in RO#8 in Subframe 9 (Uplink slot) of SFN k, Subframe 8 of SFN k + 2, and Subframe 9 of SFN k + 2 respectively. That is within the same time period, i.e. of two association periods (or 40 ms in this example), the SBFD UE can achieve 4 × PRACH repetitions compared to just 2 × PRACH repetitions by the legacy TDD UE. Another way to look at this is that an SBFD UE can complete a 2 × PRACH repetitions within one association period rather than two association periods as compared to a legacy UE. For example, a 2 × PRACH repetition of SSB#4 can use RO#8 in Subframe 8 and Subframe 9 of SFN k. Separate power control for UL transmission in SBFD and non-SBFD OFDM symbols has been proposed [10]. The rationale for this is that SBFD OFDM symbols have a different interference environment than non-SBFD OFDM symbols. For example, SBFD OFDM symbols may experience CLI from DL transmissions in an adjacent DL sub-band, whereas non-SBFD OFDM symbols may not suffer from such CLI. Therefore, an UL transmission in SBFD OFDM symbols may require a higher transmission power to overcome the CLI compared to an UL transmission in non-SBFD OFDM symbols. UL signals at the gNB may also be received using different antenna panels depending on whether those UL signals were transmitted in SBFD or non-SBFD OFDM symbols, and so they may be transmitted over different radio channels. PRACH repetitions may be transmitted in both SBFD and non-SBFD ROs, and they may therefore require different transmission powers. However, the existing (Rel-18) PRACH repetition power control assumes a single transmission power for all its repetitions, as described above with reference to equations (1) and (2). Hence, the technical problem to solve is that a new mechanism is required to handle the power control for PRACH transmissions (including PRACH repetition transmissions) under SBFD operations. Embodiments of the present technique seek to provide solutions to such a technical problem. Power Control for SBFD PRACH Figure 16 shows a part schematic, part message flow diagram representation of a wireless communications system comprising a communications device 101 (e.g. a UE 14) and an infrastructure equipment 102 (e.g. a gNB / TRP 10) in accordance with at least some embodiments of the present technique. Here, the communications device 101 is a sub-band full duplex, SBFD, capable communications device (SBFD UE), meaning that it is able to understand SBFD configurations and transmit signals and receive signals at the same time (i.e. in accordance with a full duplex operation) using configured SBFD UL and DL sub-bands. The communications device 101 may be configured to transmit signals to and/or receive signals from the wireless communications network, for example, to and from the infrastructure equipment 102. Specifically, the communications device 101 may be configured to transmit data to and/or receive data from the wireless communications network (e.g. to/from the infrastructure equipment 102) via a wireless radio interface provided by the wireless communications network (e.g. a Uu interface between the communications device 101 and the Radio Access Network (RAN), which includes the infrastructure equipment 102). The communications device 101 and the infrastructure equipment 102 each comprise a transceiver (or transceiver circuitry) 101.1, 102.1, and a controller (or controller circuitry) 101.2, 102.2. Each of the controllers 101.2, 102.2 may be, for example, a microprocessor, a CPU, or a dedicated chipset, etc. The controllers 101.2, 102.2 may also each be equipped with a memory unit (which is not shown in Figure 16). As shown in the example of Figure 16, the controller 101.2 of the communications device 101 is configured to control the transceiver 101.1 of the communications device 101 to determine 103 that the communications device 101 is to perform a random access procedure with the infrastructure equipment 102 (e.g. for initial access to the infrastructure equipment from idle mode, or to obtain a timing advance, or for beam management, etc.), to calculate 104 an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment 102 as part of the random access procedure, wherein the communications device 101 is configured to determine whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface, and to transmit 105 the PRACH preamble to the infrastructure equipment 102 in the at least one RO and using the calculated uplink transmission power. Here, the PRACH preamble may be transmitted 105 once in a single RO (i.e. the one or more ROs is just one RO), or the PRACH preamble may be transmitted 105 in accordance with PRACH repetitions. In other words, the PRACH preamble transmitted 105 in the at least one RO may be one of a plurality of repetitions of the PRACH preamble, and wherein each of the plurality of PRACH preambles is to be transmitted in either an SBFD RO or a non-SBFD RO. Essentially then, embodiments of the present technique, as exemplified by the example wireless communications system of Figure 16 for example, propose the introduction of an offset K_SBFD, for determining the transmit power P_PRACH for a PRACH preamble that involves using SBFD RO(s) for the transmission of that PRACH preamble. For example, where the PRACH preamble is transmitted in accordance with PRACH repetitions, the offset K_SBFD can be used to calculate the transmission power if at least one of these PRACH repetitions is transmitted in an SBFD RO. It should however be noted that arrangements of embodiments of the present technique are also applicable for the case where there is no repetition, i.e. N_PRACH = 1. It should also be appreciated that, in accordance with arrangements of embodiments of the present technique, the value of K_SBFD can be positive or negative. For example, it might be beneficial to make K_SBFD negative and apply it to the calculation of transmission power for SBFD ROs, so to avoid cross link interference to another UE receiving in a DL SUBFD sub band. It might also be beneficial to make K_SBFD negative and apply it to the calculation of transmission power for non-SBFD ROs (rather than being positive and applied to the calculation of transmission power for SBFD ROs) to enable the UE to power down, so as to reduce interference in the uplink. In some arrangements of embodiments of the present technique, the said offset K_SBFD is applied to the legacy equation (1) for determining P_PRACH. In other words, the communications device may be configured to apply the offset when calculating the uplink transmission power by determining that the uplink transmission power is equal to the smaller of: a maximum uplink transmission power configured for the communications device, and the sum of a PRACH target reception power at the infrastructure equipment, a pathloss between the communications device and the infrastructure equipment, and the offset. The offset can be summed together with the PRACH target reception power P_PRACH,target and the pathloss PL while determining the min function. That is: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD} (3) Alternatively, in some arrangements of embodiments of the present technique, the said offset K_SBFD is factored into the PRACH target reception power P_PRACH,target. That is, for PRACH repetition transmissions with SBFD RO, the PRACH target reception power is P_{PRACH,target,SBFD}, which can then be applied to the legacy equation (1) instead of P_PRACH,target. That is: P_{PRACH,target,SBFD} = P_PRACH,target + K_SBFD (4) In some arrangements of embodiments of the present technique, the said offset K_SBFD consists of a set of n offsets {K_SBFD1, K_SBFD2, K_SBFD3, …, K_SBFD#n}. The application of this set of n offsets are described in some of the forthcoming arrangements described below. It should be noted that the values in the set can be the same or different, e.g. K_SBFD1 = K_SBFD3 but K_SBFD1 ^ K_SBFD2. In some arrangements of embodiments of the present technique, the said K_SBFD is applied on a per-RO basis. Here the UE applies the factor K_SBFD to P_PRACH if that PRACH is transmitted on a SBFD RO, otherwise it does not apply the K_SBFD factor, i.e. use the legacy PRACH transmit power determination. It should be noted that such arrangements are applicable whether the PRACH is transmitted with repetitions or without repetition, i.e. it is applicable for N_PRACH ^ 1. For the case where N_PRACH = 1 therefore, the communications device may be configured to determine that the at least one RO (i.e. single RO carrying the PRACH preamble transmission without repetition) is an SBFD RO, and to apply the offset when calculating the uplink transmission power based on determining that the at least one RO is an SBFD RO. For the case where N_PRACH > 1, i.e. PRACH with repetitions, the UE determines the transmit power of each RO based on whether it is an SBFD RO or a non-SBFD RO. In other words, the communications device may be configured to determine, for each repetition of the PRACH preamble, whether to apply the offset to the uplink transmission power for that repetition of the PRACH preamble dependent on whether the RO in which that repetition of the PRACH preamble is to be transmitted is an SBFD RO or a non- SBFD RO. That is, the PRACH transmit power P_PRACH using such arrangements varies depending on the type of RO used for each of the N_PRACH PRACH repetition. Using the example in Figure 15, for 4 ^ PRACH repetitions, the UE selected RO#8 which is associated with SSB#4, where the PRACH transmit power is as follows. For SBFD RO of RO#8 in Subframe 8 of SFN k and SFN k + 2, the PRACH transmit power is: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD} (5) For non-SBFD RO of RO#8 in Subframe 9 of SFN k and SFN k + 2, the PRACH transmit power is: P_PRACH = min{P_CMAX, P_PRACH,target + PL} (6) It should be noted that the UE can use the same path loss PL determined for the first PRACH repetition, which would reduce processing at the UE. This is of course up to UE implementation. In some arrangements of embodiments of the present technique, where K_SBFD consists of n offsets, the value n = 2, i.e. there are two offsets K_SBFD1 and K_SBFD2. The UE applies K_SBFD1 if the PRACH repetition is transmitted on a SBFD RO and K_SBFD2 if the PRACH repetition is transmitted on a non-SBFD RO. In other words, the offset may be one of a plurality of offsets, and wherein the communications device may be configured to determine, for each repetition of the PRACH preamble, to apply a first of the plurality of offsets to the uplink transmission power for that repetition of the PRACH preamble if the RO in which that repetition of the PRACH preamble is to be transmitted is an SBFD RO, or to determine, for each repetition of the PRACH preamble, to apply a second of the plurality of offsets to the uplink transmission power for that repetition of the PRACH preamble if the RO in which that repetition of the PRACH preamble is to be transmitted is a non-SBFD RO. It should be noted here that if K_SBFD2 = 0, then the outcome of such arrangements is the same as those described with reference to equations (5) and (6) where only one offset is used, since using K_SBFD2 = 0 would simplify down to equation (6). Such arrangements therefore allow the gNB to have flexibility in managing the power of PRACH in different types of RO. Using the same example in Figure 15, the PRACH transmit power is as follows. For SBFD RO of RO#8 in Subframe 8 of SFN k and SFN k + 2, the PRACH transmit power is: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD1} (7) For non-SBFD RO of RO#8 in Subframe 9 of SFN k and SFN k + 2, the PRACH transmit power is: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD2} (8) In some arrangements of embodiments of the present technique, the said K_SBFD is applied to a set of N_PRACH ROs of N_PRACH PRACH repetitions, if one or more of the N_PRACH ROs is an SBFD RO. In other words, the communications device may be configured to determine to apply the offset to the uplink transmission power for all of the repetitions of the PRACH preamble if the RO in which at least one of the repetitions of the PRACH preamble is to be transmitted is an SBFD RO. Here, all the N_PRACH ROs use the same transmit power. That is, the PRACH transmit power P_PRACH is constant for all the PRACH repetitions. Such arrangements maintain the legacy PRACH transmit power for PRACH repetition mechanism where the UE uses a constant power for all PRACH repetitions. Using the example in Figure 15 again, the UE determines the PRACH transmit power P_PRACH depending upon the presence or absence of SBFD RO, i.e.: If the UE selects a 4 ^ PRACH repetition using RO#8, where the set of ROs consists of two SBFD RO#8 and two non-SBFD RO#8, the UE applies the K_SBFD offset and transmits all the PRACH repetitions using P_PRACH determined as: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD} (9) If the UE selects a 2 ^ PRACH repetition using only non-SBFD RO#3, which is associated with SSB#2, and consists of RO#3 in Subframe 4 of SFN k and SFN k + 2, the UE transmits all the PRACH repetitions without applying the K_SBFD offset, that is using P_PRACH determined as: P_PRACH = min{P_CMAX, P_PRACH,target + PL} (10) In some arrangements of embodiments of the present technique, whether K_SBFD is applied to a set of N_PRACH ROs of N_PRACH PRACH repetitions depends on the number of SBFD ROs N_RO-SBFD in the set of N_PRACH ROs. In other words, the communications device may be configured to determine to apply the offset to the uplink transmission power for all of the repetitions of the PRACH preamble if a number of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs is greater than a threshold number. That is, if N_RO-SBFD > a threshold T_RO-SBFD, then K_SBFD is applied otherwise K_SBFD is not applied to the PRACH transmit power P_PRACH. Such arrangements recognise that if a small number of SBFD ROs are used in a PRACH repetition, then it may not be beneficial to the network to apply the K_SBFD offset to the PRACH transmit power, as it may create interferences in the uplink for PRACH transmitted in non- SBFD ROs. The value of the threshold T_RO-SBFD can be configured by the network or fixed in the specifications. In some arrangements of embodiments of the present technique, whether K_SBFD is applied to a set of N_PRACH ROs of N_PRACH PRACH repetitions depends on the percentage of SBFD ROs N_RO-SBFD in set of N_PRACH ROs. In other words, the communications device may be configured to determine to apply the offset to the uplink transmission power for all of the repetitions of the PRACH preamble if a percentage of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs is greater than a threshold percentage. That is, if N_RO-SBFD/N_PRACH > a threshold T_SBFD-NPRACH, then K_SBFD is applied otherwise K_SBFD is not applied to the PRACH transmit power P_PRACH. The value of the threshold T_{SBFD- NPRACH} can be configured by the network or fixed in the specifications. In some arrangements of embodiments of the present technique, different offset K_SBFD is used for different set of N_PRACH ROs. In a general case, a set of offsets {K_SBFD1, K_SBFD2, K_SBFD3, …, K_SBFD#n} is applied to n different set of N_PRACH ROs, where the sets can consist of different repetition factors, different SSB associations, RO in different frequency locations, etc. In other words, the offset may be one of a plurality of offsets and a set of ROs in which the plurality of repetitions of the PRACH preamble are to be transmitted may be one of a plurality of sets of ROs, and the communications device may be configured to determine to apply one of the plurality of offsets dependent on which of the plurality of sets of ROs are to be used for transmitting the plurality of repetitions of the PRACH preamble, wherein each of the plurality of offsets may be associated with a different one of the plurality of sets of ROs. Such arrangements are applicable even to cases where there are no SBFD ROs in the set of ROs, since the network can set the corresponding offset to zero (or some other values). Such arrangements provide flexibility for the network to manage the power offset for each individual set of N_PRACH ROs. In an implementation of such arrangements, where different values of K_SBFD are used for different sets of N_PRACH ROs, a separate K_SBFD is used for PRACH repetition with different repetition factor. In other words, each of the plurality of sets of ROs may be configured with a different repetition number defining the number of repetitions of the PRACH preamble. That is, a set of n = 3 K_SBFD offsets {K_SBFD1, K_SBFD2, K_SBFD3} is applied to the set of ROs with PRACH repetition {2, 4, 8} if the set of RO meets one or more of the above-described arrangements of embodiments of the present technique for the application of the offset. For example: For a set of N_PRACH = 2 ROs of 2 ^ PRACH repetitions, where one or more SBFD RO is used: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD1} (11) For a set of N_PRACH = 4 ROs of 4 ^ PRACH repetitions, where one or more SBFD RO is used: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD2} (12) For a set of N_PRACH = 8 ROs of 8 ^ PRACH repetitions, where one or more SBFD RO is used: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD3} (13) In another implementation of such arrangements, where different values of K_SBFD are used for different sets of N_PRACH ROs, a different K_SBFD is for different SSB association. In other words, each of the plurality of sets of ROs may be associated with a different synchronisation signal block, SSB. For example, if five SSBs are configured, then there may be n = 5 K_SBFD offsets {K_SBFD1, K_SBFD2, K_SBFD3, K_SBFD4, K_SBFD5} for {SSB#1, SSB#2, SSB#3, SSB#4, SSB#5} respectively. In some arrangements of embodiments of the present technique, the value of K_SBFD offset is configured by the network. In other words, the communications device may be configured to receive, from the infrastructure equipment, an indication of a value of the offset. If a set of K_SBFD offsets are implemented, then the network configured the value for each of the offsets in the set of n K_SBFD offsets {K_SBFD1, K_SBFD2, K_SBFD3, …, K_SBFD#n}. In some arrangements of embodiments of the present technique, the value of K_SBFD offset is fixed in the specifications. In other words, a value of the offset may be preconfigured and known to the communications device. In some arrangements of embodiments of the present technique, the value of K_SBFD is dependent upon the number of SBFD ROs N_RO-SBFD, in the set of N_PRACH ROs of a PRACH repetition. In other words, the communications device may be configured to determine a value of the offset dependent on a number of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs. In an implementation of such arrangements, the offset K’_SBFD applied to P_PRACH is K’_SBFD = K_SBFD/N_{RO- SBFD}., i.e.: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K’_SBFD} (14) P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD/N_RO-SBFD} In another implementation of such arrangements, the offset K’_SBFD = K_SBFD – 10 log₁₀(N_RO-SBFD), i.e.: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K_SBFD – 10 log₁₀(N_RO-SBFD)} In some arrangements of embodiments of the present technique, the value of K_SBFD is dependent upon the percentage of SBFD RO in the set of N_PRACH ROs. In other words, the communications device may be configured to determine a value of the offset dependent on a percentage of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs. In an implementation of such arrangements, the offset K’_SBFD applied to P_PRACH is K’_SBFD = K_SBFD ^ (N_{RO- SBFD}/N_PRACH), i.e.: P_PRACH = min{P_CMAX, P_PRACH,target + PL + K’_SBFD} (16) In another implementation of such arrangements, the offset K’_SBFD = K_SBFD + 10 log₁₀(N_RO-SBFD/N_PRACH), i.e.: = P_PRACH = It will be appreciated by those skilled in the art that the arrangements of embodiments of the present technique described above defining how the communications device determines or receives configuration of the value of the offset (or of the multiple set of offsets) may equally be applied to the cases where the offset K_SBFD is applied per-RO in a set of N_PRACH ROs and where the offset is applied once per set of N_PRACH ROs. Figure 17 shows a flow diagram illustrating an example process of communications in a communications system in accordance with embodiments of the present technique. The process shown by Figure 17 is specifically a method of operating a communications device (e.g. UE) configured to transmit signals to and/or to receive signals from an infrastructure equipment (e.g. a gNB) of a wireless communications network, where here, the communications device is a sub-band full duplex, SBFD, capable communications device. The method begins in step S1. The method comprises, in step S2, determining that the communications device is to perform a random access procedure with the infrastructure equipment. In step S3, the process comprises calculating an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment as part of the random access procedure, wherein the communications device determines whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface. The method then comprises, in step S4, transmitting the PRACH preamble to the infrastructure equipment in the at least one RO and using the calculated uplink transmission power. The process ends in step S5. Those skilled in the art would appreciate that the method shown by Figure 17 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 16, and further described with respect to the example implementation shown in Figure 15, it would be clear to those skilled in the art that they could be equally applied to other systems to those described herein, provided that these are within the scope of the claims. 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, provided that these are within the scope of the claims. The following numbered paragraphs provide further example aspects and features of the present technique: Paragraph 1. A method of operating a communications device configured to transmit signals to and/or to receive signals from an infrastructure equipment of a wireless communications network via a radio access interface between the communications device and the infrastructure equipment, the communications device being a sub-band full duplex, SBFD, capable communications device, the method comprising determining that the communications device is to perform a random access procedure with the infrastructure equipment, calculating an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment as part of the random access procedure, wherein the communications device determines whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface, and transmitting the PRACH preamble to the infrastructure equipment in the at least one RO and using the calculated uplink transmission power. Paragraph 2. A method according to Paragraph 1, comprising determining that the at least one RO is an SBFD RO, and applying the offset when calculating the uplink transmission power based on determining that the at least one RO is an SBFD RO. Paragraph 3. A method according to Paragraph 1 or Paragraph 2, comprising applying the offset when calculating the uplink transmission power by determining that the uplink transmission power is equal to the smaller of: a maximum uplink transmission power configured for the communications device, and the sum of a PRACH target reception power at the infrastructure equipment, a pathloss between the communications device and the infrastructure equipment, and the offset. Paragraph 4. A method according to any of Paragraphs 1 to 3, wherein the offset is one of a plurality of offsets. Paragraph 5. A method according to any of Paragraphs 1 to 4, wherein the PRACH preamble transmitted in the at least one RO is one of a plurality of repetitions of the PRACH preamble, and wherein each of the plurality of PRACH preambles is to be transmitted in either an SBFD RO or a non-SBFD RO. Paragraph 6. A method according to Paragraph 5, comprising determining, for each repetition of the PRACH preamble, whether to apply the offset to the uplink transmission power for that repetition of the PRACH preamble dependent on whether the RO in which that repetition of the PRACH preamble is to be transmitted is an SBFD RO or a non-SBFD RO. Paragraph 7. A method according to Paragraph 5 or Paragraph 6, wherein the offset is one of a plurality of offsets, and wherein the method comprises determining, for each repetition of the PRACH preamble, to apply a first of the plurality of offsets to the uplink transmission power for that repetition of the PRACH preamble if the RO in which that repetition of the PRACH preamble is to be transmitted is an SBFD RO, or determining, for each repetition of the PRACH preamble, to apply a second of the plurality of offsets to the uplink transmission power for that repetition of the PRACH preamble if the RO in which that repetition of the PRACH preamble is to be transmitted is a non-SBFD RO. Paragraph 8. A method according to any of Paragraphs 5 to 7, comprising determining to apply the offset to the uplink transmission power for all of the repetitions of the PRACH preamble if the RO in which at least one of the repetitions of the PRACH preamble is to be transmitted is an SBFD RO. Paragraph 9. A method according to any of Paragraphs 5 to 8, comprising determining to apply the offset to the uplink transmission power for all of the repetitions of the PRACH preamble if a number of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs is greater than a threshold number. Paragraph 10. A method according to any of Paragraphs 5 to 9, comprising determining to apply the offset to the uplink transmission power for all of the repetitions of the PRACH preamble if a percentage of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs is greater than a threshold percentage. Paragraph 11. A method according to any of Paragraphs 5 to 10, wherein the offset is one of a plurality of offsets and a set of ROs in which the plurality of repetitions of the PRACH preamble are to be transmitted is one of a plurality of sets of ROs, and wherein the method comprises determining to apply one of the plurality of offsets dependent on which of the plurality of sets of ROs are to be used for transmitting the plurality of repetitions of the PRACH preamble, wherein each of the plurality of offsets is associated with a different one of the plurality of sets of ROs. Paragraph 12. A method according to Paragraph 11, wherein each of the plurality of sets of ROs is configured with a different repetition number defining the number of repetitions of the PRACH preamble. Paragraph 13. A method according to Paragraph 11 or Paragraph 12, wherein each of the plurality of sets of ROs is associated with a different synchronisation signal block, SSB. Paragraph 14. A method according to any of Paragraphs 1 to 13, comprising receiving, from the infrastructure equipment, an indication of a value of the offset. Paragraph 15. A method according to any of Paragraphs 1 to 14, wherein a value of the offset is preconfigured and known to the communications device. Paragraph 16. A method according to any of Paragraphs 1 to 15, comprising determining a value of the offset dependent on a number of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs. Paragraph 17. A method according to any of Paragraphs 1 to 16, comprising determining a value of the offset dependent on a percentage of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs. Paragraph 18. A communications device, the communications device being a sub-band full duplex, SBFD, capable communications device and comprising transceiver circuitry configured to transmit signals to and/or to receive signals from an infrastructure equipment of a wireless communications network via a radio access interface between the communications device and the infrastructure equipment, and controller circuitry configured in combination with the transceiver circuitry to determine that the communications device is to perform a random access procedure with the infrastructure equipment, to calculate an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment as part of the random access procedure, wherein the communications device is configured to determine whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface, and to transmit the PRACH preamble to the infrastructure equipment in the at least one RO and using the calculated uplink transmission power. Paragraph 19. Circuitry for a communications device, the communications device being a sub-band full duplex, SBFD, capable communications device, the circuitry comprising transceiver circuitry configured to transmit signals to and/or to receive signals from an infrastructure equipment of a wireless communications network via a radio access interface between the communications device and the infrastructure equipment, and controller circuitry configured in combination with the transceiver circuitry to determine that the circuitry is to perform a random access procedure with the infrastructure equipment, to calculate an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment as part of the random access procedure, wherein the circuitry is configured to determine whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface, and to transmit the PRACH preamble to the infrastructure equipment in the at least one RO and using the calculated uplink transmission power. Paragraph 20. A method of operating an infrastructure equipment forming part of a wireless communications network and configured to transmit signals to and/or to receive signals from a communications device via a radio access interface between the communications device and the infrastructure equipment, the communications device being a sub-band full duplex, SBFD, capable communications device, the method comprising receiving, from the communications device in one or more physical random access channel, PRACH, occasion, ROs, and in accordance with an uplink transmission power, a PRACH preamble as part of a random access procedure performed by the infrastructure equipment with the communications device, wherein an offset is applied to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface. Paragraph 21. An infrastructure equipment forming part of a wireless communications network, the infrastructure equipment comprising transceiver circuitry configured to transmit signals to and/or to receive signals from a communications device via a radio access interface between the communications device and the infrastructure equipment, the communications device being a sub-band full duplex, SBFD, capable communications device, and controller circuitry configured in combination with the transceiver circuitry to receive, from the communications device in one or more physical random access channel, PRACH, occasion, ROs, and in accordance with an uplink transmission power, a PRACH preamble as part of a random access procedure performed by the infrastructure equipment with the communications device, wherein an offset is applied to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface. Paragraph 22. Circuitry for an infrastructure equipment forming part of a wireless communications network, the circuitry comprising transceiver circuitry configured to transmit signals to and/or to receive signals from a communications device via a radio access interface between the communications device and the infrastructure equipment, the communications device being a sub-band full duplex, SBFD, capable communications device, and controller circuitry configured in combination with the transceiver circuitry to receive, from the communications device in one or more physical random access channel, PRACH, occasion, ROs, and in accordance with an uplink transmission power, a PRACH preamble as part of a random access procedure performed by the circuitry with the communications device, wherein an offset is applied to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface. Paragraph 23. A wireless communications system comprising a communications device according to Paragraph 18 and an infrastructure equipment according to Paragraph 21. Paragraph 24. 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 17 or Paragraph 20. Paragraph 25. A non-transitory computer-readable storage medium storing a computer program according to Paragraph 24. It will be appreciated that the above description for clarity has described embodiments with reference to different functional units, circuitry and/or processors. However, it will be apparent that any suitable distribution of functionality between different functional units, circuitry and/or processors may be used without detracting from the embodiments. Described embodiments may be implemented in any suitable form including hardware, software, firmware or any combination of these. Described embodiments may optionally be implemented at least partly as computer software running on one or more data processors and/or digital signal processors. The elements and components of any embodiment may be physically, functionally and logically implemented in any suitable way. Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the disclosed embodiments may be implemented in a single unit or may be physically and functionally distributed between different units, circuitry and/or processors. Although the present disclosure has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognise that various features of the described embodiments may be combined in any manner suitable to implement the technique.

References [1] Holma H. and Toskala A, “LTE for UMTS OFDMA and SC-FDMA based radio access”, John Wiley and Sons, 2009. [2] TR 38.913, “3^rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on Scenarios and Requirements for Next Generation Access Technologies (Release 14)”, 3GPP, v14.3.0, August 2017. [3] RP-213591, “New SI: Study on evolution of NR duplex operation,” CMCC, RAN#94e, December 2021. [4] RP-220633, “Revised SID: Study on evolution of NR duplex operation,” CMCC, RAN#95e, March 2022. [5] RP-234035, “New WID: Evolution of NR duplex operation: Sub-band full duplex (SBFD),” CMCC, RAN#102, December 2023. [6] European Patent No.3545716. [7] TS 38.211 “Physical channels and modulation (Rel-18),” 3GPP, v18.0.0, September 2023. [8] TS 38.213, “Physical layer procedures for control (Rel-18),” 3GPP, v18.0.0, September 2023. [9] European patent application number EP24155834.5. [10] R1-2403474, “Summary #3 of SBFD TX/RX/measurement procedures,” Moderator (CATT), RAN1#116bis, April 2024.

Claims

CLAIMS What is claimed is: 1. A method of operating a communications device configured to transmit signals to and/or to receive signals from an infrastructure equipment of a wireless communications network via a radio access interface between the communications device and the infrastructure equipment, the communications device being a sub-band full duplex, SBFD, capable communications device, the method comprising determining that the communications device is to perform a random access procedure with the infrastructure equipment, calculating an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment as part of the random access procedure, wherein the communications device determines whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface, and transmitting the PRACH preamble to the infrastructure equipment in the at least one RO and using the calculated uplink transmission power.

2. A method according to Claim 1, comprising determining that the at least one RO is an SBFD RO, and applying the offset when calculating the uplink transmission power based on determining that the at least one RO is an SBFD RO.

3. A method according to Claim 1, comprising applying the offset when calculating the uplink transmission power by determining that the uplink transmission power is equal to the smaller of: a maximum uplink transmission power configured for the communications device, and the sum of a PRACH target reception power at the infrastructure equipment, a pathloss between the communications device and the infrastructure equipment, and the offset.

4. A method according to Claim 1, wherein the offset is one of a plurality of offsets.

5. A method according to Claim 1, wherein the PRACH preamble transmitted in the at least one RO is one of a plurality of repetitions of the PRACH preamble, and wherein each of the plurality of PRACH preambles is to be transmitted in either an SBFD RO or a non-SBFD RO.

6. A method according to Claim 5, comprising determining, for each repetition of the PRACH preamble, whether to apply the offset to the uplink transmission power for that repetition of the PRACH preamble dependent on whether the RO in which that repetition of the PRACH preamble is to be transmitted is an SBFD RO or a non-SBFD RO.

7. A method according to Claim 5, wherein the offset is one of a plurality of offsets, and wherein the method comprises determining, for each repetition of the PRACH preamble, to apply a first of the plurality of offsets to the uplink transmission power for that repetition of the PRACH preamble if the RO in which that repetition of the PRACH preamble is to be transmitted is an SBFD RO, or determining, for each repetition of the PRACH preamble, to apply a second of the plurality of offsets to the uplink transmission power for that repetition of the PRACH preamble if the RO in which that repetition of the PRACH preamble is to be transmitted is a non-SBFD RO.

8. A method according to Claim 5, comprising determining to apply the offset to the uplink transmission power for all of the repetitions of the PRACH preamble if the RO in which at least one of the repetitions of the PRACH preamble is to be transmitted is an SBFD RO.

9. A method according to Claim 5, comprising determining to apply the offset to the uplink transmission power for all of the repetitions of the PRACH preamble if a number of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs is greater than a threshold number.

10. A method according to Claim 5, comprising determining to apply the offset to the uplink transmission power for all of the repetitions of the PRACH preamble if a percentage of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs is greater than a threshold percentage.

11. A method according to Claim 5, wherein the offset is one of a plurality of offsets and a set of ROs in which the plurality of repetitions of the PRACH preamble are to be transmitted is one of a plurality of sets of ROs, and wherein the method comprises determining to apply one of the plurality of offsets dependent on which of the plurality of sets of ROs are to be used for transmitting the plurality of repetitions of the PRACH preamble, wherein each of the plurality of offsets is associated with a different one of the plurality of sets of ROs.

12. A method according to Claim 11, wherein each of the plurality of sets of ROs is configured with a different repetition number defining the number of repetitions of the PRACH preamble.

13. A method according to Claim 11, wherein each of the plurality of sets of ROs is associated with a different synchronisation signal block, SSB.

14. A method according to Claim 1, comprising receiving, from the infrastructure equipment, an indication of a value of the offset.

15. A method according to Claim 1, wherein a value of the offset is preconfigured and known to the communications device.

16. A method according to Claim 1, comprising determining a value of the offset dependent on a number of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs.

17. A method according to Claim 1, comprising determining a value of the offset dependent on a percentage of the repetitions of the PRACH preamble that are to be transmitted in SBFD ROs.

18. A communications device, the communications device being a sub-band full duplex, SBFD, capable communications device and comprising transceiver circuitry configured to transmit signals to and/or to receive signals from an infrastructure equipment of a wireless communications network via a radio access interface between the communications device and the infrastructure equipment, and controller circuitry configured in combination with the transceiver circuitry to determine that the communications device is to perform a random access procedure with the infrastructure equipment, to calculate an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment as part of the random access procedure, wherein the communications device is configured to determine whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface, and to transmit the PRACH preamble to the infrastructure equipment in the at least one RO and using the calculated uplink transmission power.

19. Circuitry for a communications device, the communications device being a sub-band full duplex, SBFD, capable communications device, the circuitry comprising transceiver circuitry configured to transmit signals to and/or to receive signals from an infrastructure equipment of a wireless communications network via a radio access interface between the communications device and the infrastructure equipment, and controller circuitry configured in combination with the transceiver circuitry to determine that the circuitry is to perform a random access procedure with the infrastructure equipment, to calculate an uplink transmission power at which to transmit a physical random access channel, PRACH, preamble in one or more PRACH, occasion, ROs, to the infrastructure equipment as part of the random access procedure, wherein the circuitry is configured to determine whether to apply an offset to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface, and to transmit the PRACH preamble to the infrastructure equipment in the at least one RO and using the calculated uplink transmission power.

20. A method of operating an infrastructure equipment forming part of a wireless communications network and configured to transmit signals to and/or to receive signals from a communications device via a radio access interface between the communications device and the infrastructure equipment, the communications device being a sub-band full duplex, SBFD, capable communications device, the method comprising receiving, from the communications device in one or more physical random access channel, PRACH, occasion, ROs, and in accordance with an uplink transmission power, a PRACH preamble as part of a random access procedure performed by the infrastructure equipment with the communications device, wherein an offset is applied to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface.

21. An infrastructure equipment forming part of a wireless communications network, the infrastructure equipment comprising transceiver circuitry configured to transmit signals to and/or to receive signals from a communications device via a radio access interface between the communications device and the infrastructure equipment, the communications device being a sub-band full duplex, SBFD, capable communications device, and controller circuitry configured in combination with the transceiver circuitry to receive, from the communications device in one or more physical random access channel, PRACH, occasion, ROs, and in accordance with an uplink transmission power, a PRACH preamble as part of a random access procedure performed by the infrastructure equipment with the communications device, wherein an offset is applied to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface.

22. Circuitry for an infrastructure equipment forming part of a wireless communications network, the circuitry comprising transceiver circuitry configured to transmit signals to and/or to receive signals from a communications device via a radio access interface between the communications device and the infrastructure equipment, the communications device being a sub-band full duplex, SBFD, capable communications device, and controller circuitry configured in combination with the transceiver circuitry to receive, from the communications device in one or more physical random access channel, PRACH, occasion, ROs, and in accordance with an uplink transmission power, a PRACH preamble as part of a random access procedure performed by the circuitry with the communications device, wherein an offset is applied to the uplink transmission power dependent on whether at least one of the ROs is an SBFD RO which is contained within SBFD symbols of the radio access interface or a non-SBFD RO which is contained within non-SBFD uplink symbols of the radio access interface.

23. A wireless communications system comprising a communications device according to Claim 18 and an infrastructure equipment according to Claim 21.

24. A computer program comprising instructions which, when loaded onto a computer, cause the computer to perform a method according to Claim 1 or Claim 20.

25. A non-transitory computer-readable storage medium storing a computer program according to Claim 24.