Infrastructure equipment, core network apparatus, communications device and methods

Abstract

A method of operating infrastructure equipment of a radio access network of a wireless communications network is provided. The method comprises receiving an indication that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session. The first communications path is used for communications between a communications device and a core network of the wireless communications network via the infrastructure equipment of the radio access network. The MA-PDU session comprises a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network. The method comprises, in response to receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session, transmitting an inactive state indication to the communications device. The inactive state indication indicates to the communications device to transition to an inactive state for communications with the infrastructure equipment of the radio access network.

Description

[0001] INFRASTRUCTURE EQUIPMENT, CORE NETWORK APPARATUS, COMMUNICATIONS DEVICE AND METHODS

[0002] BACKGROUND

[0003] Field of Disclosure

[0004] The present disclosure relates to infrastructure equipment, a core network apparatus, a communications device, and methods of operating infrastructure equipment, a core network apparatus, a communications device.

[0005] The present application claims Paris Convention priority from European patent application number 23184830.0, the contents of which are hereby incorporated by reference in their entirety.

[0006] Description of Related Art

[0007] 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.

[0008] Wireless communications networks are now supporting communications to a wider range of communications devices and user equipment for a variety of applications and data traffic profiles and types. For example, communications are now supported with devices including reduced complexity devices, machine type communication (MTC) devices, high resolution video displays, virtual reality headsets and so on. Some of these different types of devices may be deployed in very large numbers, for example low complexity devices for supporting the “The Internet of Things”, and may typically be associated with the transmissions of relatively small amounts of data with relatively high latency tolerance. Other types of device, for example supporting high-definition video streaming, may be associated with transmissions of relatively large amounts of data with relatively low latency tolerance.

[0009] In order to provide coverage for an increasing range of devices, such as loT, 5G radio access technologies (RAT), also referred to as new radio (NR) systems, includes aspects which are devised to support connectivity over a wide range of environments.

[0010] 5G NR has continuously evolved and the current work plan includes 5G-NR-advanced in which some further enhancements are expected, especially to support new use-cases / scenarios with higher requirements. The desire to support these new use-cases and scenarios gives rise to new challenges for handling communication device power usage in wireless communications systems that need to be addressed.

[0011] SUMMARY OF THE DISCEOSURE

[0012] The present disclosure can help address or mitigate at least some of the issues discussed above.

[0013] Embodiments can provide a method of operating infrastructure equipment of a radio access network of a wireless communications network. The method comprises receiving an indication that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session. The first communications path is used for communications between a communications device and a core network of the wireless communications network via the infrastructure equipment of the radio access network. The MA-PDU session comprises a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network. The method comprises, in response to receiving the indication that communications are no longer expected on the first communications path of the MA- PDU session, transmiting an inactive state indication to the communications device. The inactive state indication indicates to the communications device to transition to an inactive state for communications with the infrastructure equipment of the radio access network.

[0014] Embodiments can also provide a method of operating a core network apparatus of a wireless communications network. The method comprises determining that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session. The first communications path is used for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network. The MA-PDU session comprises a second communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network. In response, the method comprises, transmiting an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session.

[0015] Embodiments can also provide a method of operating communications device. The method comprises determining that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session. The first communications path is used for communications between the communications device and a core network of a wireless communications network via infrastructure equipment of a radio access network of the wireless communications network. The MA-PDU session comprises a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network. In response, the method comprises transmiting an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session.

[0016] Embodiments can also provide a method of operating infrastructure equipment of a radio access network of a wireless communications network. The method comprises receiving, from a core network of the wireless communications network, an indication that communications are expected on a second communications path of a multi-access protocol data unit, MA-PDU, session. The second communications path is for communications between a communications device and the core network via the infrastructure equipment of the radio access network. The MA-PDU session comprises a first communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network. In response to receiving the indication that communications are expected on the second communications path of the MA-PDU session, the method comprises transmiting a connected state indication to the communications device, the connected state indication indicating to the communications device to transition to a connected state for communications with the infrastructure equipment of the radio access network.

[0017] Embodiments can also provide a method of operating a core network apparatus of a wireless communications network. The method comprises determining that communications are expected on a second communications path of a multi-access protocol data unit, MA-PDU, session. The second communications path is for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network. The MA-PDU session comprises a first communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network. In response, the method comprises transmiting an indication to the infrastructure equipment of the radio access network indicating that communications are expected on the second communications path of the MA-PDU session.

[0018] As will be appreciated from an understanding of the detailed description below, embodiments can provide reduced communications device power consumption.

[0019] Respective aspects and features of the present disclosure are defined in the appended claims and include a communications device (for example, a UE), and infrastructure equipment, a core network apparatus and methods for operating the same.

[0020] 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.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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:

[0023] Figure 1 schematically represents some aspects of a 5G / new radio access technology (RAT) wireless communications system which may be configured to operate in accordance with embodiments of the present disclosure;

[0024] Figure 2 is a schematic block diagram of a communications device communicating data to and / or from an infrastructure equipment (gNB) forming part of the wireless communication system shown in Figure 1 ;

[0025] Figure 3 schematically illustrates a mapping between radio bearers and QoS flows for a PDU session;

[0026] Figure 4 schematically illustrates an example of an MA-PDU session over a 3GPP access network and a non-3GPP access network;

[0027] Figure 5 schematically illustrates an example of simplified protocol stacks for an MA-PDU session over a 3GPP and non-3GPP access network;

[0028] Figure 6 schematically illustrates an example of an MA-PDU session over two 3GPP access networks;

[0029] Figure 7 schematically illustrates an example of switching between communications paths in an MA-PDU session according to conventional techniques;

[0030] Figure 8 schematically illustrates a flow diagram showing a method of operating infrastructure equipment of a radio access network in accordance with example embodiments;

[0031] Figure 9 schematically illustrates a flow diagram showing a method of operating a core network apparatus in accordance with example embodiments;

[0032] Figure 10 schematically illustrates an example of switching between communications paths in an MA- PDU session according to example embodiments; Figure I l a schematic diagram illustrating various Radio Resource Control (RRC) states which may be occupied by a UE.

[0033] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] New Radio Access Technology (5G)

[0035] An example configuration of a wireless communications network which uses some of the terminology proposed for and used in NR and 5G is shown in Figure 1. In Figure 1 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 30.

[0036] As will be appreciated by those acquainted with the wireless communications network according to a 5G standard as shown in Figure 1, the CU 40, DU 42 and TRPs 10 collectively refer to functions which are conventionally performed by a network base station or, in accordance with 5G terminology, a gNodeB (gNB). In terms of broad top-level functionality, 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 DUs and the communications devices may lie with the controlling node / central unit and / or the distributed units / TRPs.

[0037] A communications device 14 is represented in Figure 1 within the coverage area of the first communication cell 12. This communications device 14 may thus exchange signalling with the first CU 40 in the first communication cell 12 via one of the distributed units / TRPs 10 associated with the first communication cell 12. The communications devices 14 may be referred to as mobile terminals, terminals or user equipment (UE), which encompasses chip sets and have a functionality corresponding to the UE devices known for operation with wireless communications networks.

[0038] Figure 2 provides a more detailed diagram of components shown in Figure 1. Components shown in Figure 2 which are also shown in Figure 1 bear the same numerical designations and so description of these parts will not be repeated for brevity. In Figure 2, a TRP 120, which broadly corresponds to TRP 10 in Figure 1, and comprises, as a simplified representation, a transmitter 126, a receiver 124 and a controller or controlling processor 122 which may operate to control the transmitter 126 and the receiver 124 to transmit and receive radio signals to one or more UEs within a cell (not shown in Figure 2 for clarity) provided by the TRP 120. As shown in Figure 2, the TRP 120 is connected to a DU 140 via a physical interface 130 which may be a fibre optic cable, for example. The physical interface 130 therefore provides a communications link for data and signalling traffic from the TRP 120 via the DU 140 and a CU 160 to a core network 400. An interface 150 between the DU 140 and the CU 160 is known as the Fl interface which can be a physical or a logical interface. The Fl interface 150 between the DU 140 and the CU 160 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. The connection between a TRP 120 and the core network 400 can be generally referred to as a backhaul, which comprises the physical interface 130 from the TRP 120 to the DU 140 and the Fl interface 150 from the DU 140 to the CU 160.

[0039] As shown in Figure 2, the TRP 120 may be configured to transmit downlink radio signals and receive uplink radio signals from a UE 200 via a direct wireless communications link 250 which may be a Uu interface in one example. The UE 200 is shown to include a transmitter 226, a receiver 224 and a controller 222 which is configured to control the transmitter 226 and the receiver 224 to transmit uplink signals to the TRP 120 and to receive downlink signals from the TRP 120 over the wireless communications link 250 formed between the UE 200 and the TRP 120.

[0040] The transmitters 126, 226 and the receivers 124, 224, 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 122, 222, 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 2 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).

[0041] As mentioned above, the TRP 120, DU 140 and the CU 160 may collectively form the gNB 202 which is an example of infrastructure equipment of a radio access network of a wireless communications network. Therefore, references to the UE 200 communicating with the TRP 120 can alternatively be considered as references to the UE 200 communicating with the gNB 202. Furthermore, it will be appreciated that the UE 200 is an example of a communications device or wireless transceiver unit. As will be appreciated the infrastructure equipment / TRP / base station / gNB as well as the UE / communications device will in general comprise various other elements associated with its operating functionality.

[0042] PDU Session

[0043] In 5G systems, a protocol data unit (PDU) session provides end-to-end user plane connectivity between a UE and a particular data network (DN). Figure 3 schematically illustrates an example of a mapping between data radio bearers (DRBs) and Quality of Service (QoS) flows in a PDU session. As shown in Figure 3, a PDU session 608 is established between the UE 200 and a User Plane Function 606 (UPF) of the core network 400 via the gNB 202. The UPF 606 is responsible for packet routing and forwarding, packet inspection, QoS handling, and external PDU sessions for an interconnecting data network, in the 5G architecture as will be appreciated by one skilled in the art. The UE 200 communicates with the UPF 606 via the PDU session 608. Three QoS flows 610, 612, 614 belong to the PDU session 608, and are associated with DRBs 616 and 620. One PDU session may be mapped to one or more DRBs and one PDU session may have multiple QoS flows.

[0044] Each Internet Protocol (IP) packet received from the 5G core network may be assigned a particular QoS such as QoS flows 610, 612, 614. Each of the QoS flows may be characterised by a QoS flow ID and may be associated with a quality of service requirement (such as one or more of a Guaranteed Bit Rate (GBR), a maximum bit rate, a maximum latency, a permitted packet loss ratio and the like). Therefore the UE 200 is aware of the parameters associated with each of the QoS flows 610, 612, 614. The gNB 202 connected to the 5G core network 400 is also aware of the QoS flows.

[0045] The gNB 202 establishes logical connections with the UE 200 which may be DRBs 616 and 620. In accordance with a 5G system architecture as shown in Figure 3, one DRB (such as the DRB 616) may be used to transport packet data associated with two QoS flows (such as the QoS flows 610 and 612). In order to accommodate this flexibility, the gNB 202 may maintain a mapping table to store a mapping between each of the QoS flows and the respective DRB. Using the table, the gNB 202 is able to assign packets received from the 5G core network over the QoS flows 610, 612, 614 to the appropriate data radio bearers 616, 620 for transmission to the UE 200.

[0046] MA-PDU Session

[0047] 5G systems also support UEs establishing multiple Protocol Data Unit (PDU) sessions to the same data network or to different data networks over a single or multiple access networks. Such sessions are known as “Multi-Access PDU (MA-PDU) sessions”. Session establishment procedures for MA-PDUs are described in [1], Generally, in an MA-PDU session, data may be transmitted via one or both of the multiple access networks. Typically, an MA-PDUs comprises two communications paths , or “legs”, between a UE and a core network. Each of the two communications paths is over a different access network.

[0048] An example of an MA-PDU session established over multiple access networks is shown in Figure 4. As shown in Figure 4, an MA-PDU session 318 is established between a UE 302 (which may broadly correspond to UE 202) and a UPF (PDU Session Anchor (PSA)) 310 of a core network (such as core network 400) via a first communications path 322 and a second communications path 324. As will understood by a person skilled in the art, a “UPF (PSA)” is a user plane function which terminates the N6 interface of a PDU session in a 5G core network. As will be understood by a person skilled in the art, in order to support selective data routing to a data network (DN), or to support Session and Service Continuity (SSC) mode 3, a session management function (SMF) (not shown in Figure 4) may control a data path of a PDU session so that the PDU session may simultaneously correspond to multiple N6 interfaces. A UPF that terminates each of these interfaces is said to support PDU session anchor functionality and is referred to as a “UPF (PSA)”. Further details of the UPF (PSA) can be found in TS23.501, v. 18, which is hereby incorporated by reference in its entirety.

[0049] In Figure 4, the UPF (PSA) 310 is connected to a server host 312. The MA-PDU comprises two PDU sessions - one PDU session over the first communications path 322 and one PDU session over the second communications path 324. The first communications path 322 comprises a “3GPP access network” 316 and a UPF 314 (which may broadly correspond to UPF 606). The second communications path 324 comprises a “non-3GPP access network” 304, a non-3GPP Inter-Working Function (N3IWF) 306 and another UPF 308 (which may broadly correspond to UPF 606).

[0050] 3GPP access networks include any access network which operate in accordance with 3GPP protocols. Examples of networks which can include access networks configured to operate in accordance with 3GPP protocols include terrestrial networks, TNs, non-terrestrial networks, NTNs, Public Land Mobile Networks, PLMN and stand-alone non-public networks (SNPNs). For example, such networks may include gNBs which provide access for communications devices to a core network. Non-3PP access networks include any access network which does not operate in accordance with 3GPP protocols. Examples of networks which can include access networks which are not configured to operate in accordance with 3GPP protocols include wireless local area networks, WLANs. For example, a WLAN may comprise a residential gateway implementing WiFi protocols which provides access for communications devices to a core network. In some examples, as described with reference to Figure 5 below, a residential gateway may comprise both WiFi protocols and a DU protocol stack and can therefore form part of both a 3GPP and non-3GPP access network

[0051] An example of simplified protocol stacks present in an MA-PDU session over a 3GPP and non-3GPP access network is shown in Figure 5. As shown in Figure 5, the UE 302 may have a 5G access stratum (AS) layer 1204 and a WiFi protocol stack 1206 which are connected to a common non-access stratum (NAS) layer 1202. A residential gateway (RG) 1002 comprises a peer WiFi protocol stack 1208 corresponding to the WiFi protocol stack 1206 in the UE 302 and the RG 1002 comprises a distributed unit (DU) protocol stack 1210. A gNB 1010 (which may broadly correspond to gNB 202) has a DU protocol stack 1214 and a CU protocol stack 1212. The DU protocol stack 1210 in the RG 1002 and the DU protocol stack 1214 in the gNB 1010 . The DU in the RG 1002 and the DU in the gNB 1010 are connected to a single CU in the gNB 1010. Protocol stacks in a core network 1012 (which may broadly correspond to core network 400) are not shown for clarity. As indicated in Figure 5, QoS flows for providing a service to the UE 302 are set up in the NAS layer 1202 of the UE 302 when the user requests a service. The dashed lines indicate a communications path for transmission of protocol data units between the UE 302 and core network 1012 via a non-3GPP access network. The solid lines indicate a communications path for transmission protocol data units between the UE 302 and core network 1012 via a 3GPP access network. In this example, the non-3GPP includes the RG 1002 (specifically, a part of the RG 1002 implementing the WiFi protocols 1208) and the 3GPP network includes the RG 1002 (specifically, a part of the RG 1002 implementing the DU 1210 protocols) and the gNB 1010. In this example, the 3GPP access network may be comprised in an SNPN.

[0052] Generally, transmissions in MA-PDU sessions may be split, switched and steered between 3GPP and non-3GPP access networks according to Access Traffic Steering, Switching and Splitting (ATSSS) rules (see [2] and [3]).

[0053] As will be understood by a person skilled in the art, data may be transmitted with high QoS requirements (such as data transmitted via a Guaranteed Bit Rate (GBR) bearer) or low QoS requirements (such as data transmitted via a non-GBR bearer). Currently, GBR data can only be transmitted via one of the two communications paths of an MA-PDU session at any one time. There are currently no ATSSS rules which permit splitting of GBR data between the two communications paths in order to ensure the stringent QoS requirements of GBR data are met. By contrast, non-GBR data may be split, switched and steered across both of the communications paths in an MA-PDU session according to ATSS rules.

[0054] Currently, one 3GPP access network and at least one non-3GPP access network are required to support ATSSS. However, the requirement that at least one non-3GPP access network is used provides restrictions on capacity, coverage, reliability and Quality of Experience (QoE). It has therefore been proposed to configure MA-PDU sessions over two 3GPP access networks.

[0055] An example of an MA-PDU session established over two 3GPP access networks is shown in Figure 6. As shown in Figure 6, an MA-PDU session 318 is established between the UE 302 and the UPF (PSA) 310 via a first communications path 328 and a second communications path 330. The UPF (PSA) 310 is connected to the server host 312. The first communications path 328 comprises the 3GPP access network 316 and the UPF 314. The second communications path 330 comprises another 3GPP access network 326 and another UPF 308.

[0056] In some examples, at least one of the 3GPP access networks 316, 326 may be comprised in a PLMN. In such examples, the other of the 3GPP access networks 316, 326 may be comprised in the same or different PLMN, or an SNPN. In some examples, at least one of the 3GPP access networks 316, 326 may be an comprised in a SNPN. In such examples, the other of the 3GPP access networks 316, 326 may also be comprised in the same or different SNPN, or an PLMN. The UE 302 may use the same subscription credentials for access networks comprised in the same or different PLMNs, the same or different SNPNs, or a PLMN and an SNPN.

[0057] With the introduction of MA-PDU sessions with two 3GPP access networks, scenarios may arise where the QoS requirements for both 3GPP access networks are very similar or the same. For example, 3GPP access networks comprised in NTNs and TNs may be very similar or the same. In some examples, the QoS requirements for two 3GPP access networks may be the same but each of the 3GPP access networks may support a different type of service. This may be because different 3GPP access networks are optimised to support different types of service.

[0058] Therefore, since QoS requirements for 3GPP access networks may be very similar or the same, non-GBR traffic in such MA-PDU sessions with two 3GPP access networks may be required to be switched, rather than split, between the two communications paths. Therefore, there is expected to be an increase in the frequency of scenarios where data transmission is switched between communications paths.

[0059] An existing procedure for switching the transmission of data from one communications path to transmission of data via another communications path is described with reference to Figure 7.

[0060] As shown in Figure 7, an MA-PDU session is established between a UE 502 and a core network 510 via a first gNB 506 and via a second gNB 514. The UE 502 may broadly correspond to UE 202 and UE 302. The core network 510 may broadly correspond to core network 400. The first gNB 506 and via a second gNB 514 may broadly correspond to gNB 202. A first communications path comprises a wireless communications link 504 between the UE 502 and the first gNB 506, and a communications link 508 between the first gNB 506 and the core network 510. A second communications path comprises a wireless communications link 516 between the UE 502 and the second gNB 514, and a communications link 512 between the second gNB 514 and the core network 510. Phase 1 of Figure 7 is a schematic representation before a path switch. In Phase 1, the UE 502 is communicating with the core network 510 via the first communications path and is in connected state (for example, an RRC connected state) for communications via the first gNB 506. The UE 502 is in an RRC inactive state for communications via the second gNB 514 and is not communicating with the core network 510 via the second communications path. Although the UE 502 is shown in an RRC inactive state for communications via the second gNB 514 in Phase 1, the UE 502 may alternatively be in an RRC connected state for communications with the second gNB 514 but with no communications on the second communications path in Phase 1 (i.e. the second communications path is not currently being used for communications). Alternatively, the UE 502 may be in an RRC idle state for communications via the second gNB 514 in Phase 1.

[0061] The decision of whether to transmit downlink data via the first or second communications path is generally performed by a UPF(PSA) (not shown) in the core network 510. Typically, the decision of whether to transmit data via the first or second communications path is performed by the UPF(PSA) based on one or more ATSSS rules. The decision of whether to transmit uplink data via the first or second communications path is generally performed by the UE 502 based on the one or more ATSSS rules. However, if the ATSSS rules are on standby, the decision to switch uplink or downlink data are based on jitter measurements. For example, data may be transmitted over the first communications path and the UPF(PSA) may determine, based on jitter measurements, that the communications paths should be switched such that the second communications path is used for transmissions rather than the first communications path. This may be because radio channel conditions over the first communications path deteriorated due to the UE 502 moving from indoors to outdoors, for example. The decision to switch paths may alternatively be based on the methods discussed in pending international application PCT / EP2022 / 051040, published as WO 2022 / 167216, which is hereby incorporated by reference in its entirety.

[0062] As will be understood by a person skilled in the art, jitter measurements are related to variation in a delay of received packets. In some examples, jitter measurements may account for processing delays due to gNB and core network internal processing delays (such as hardware processing) and delays over a transport network. For wireless interfaces, the variation in transmission delay may be introduced by Hybrid Automatic Repeat Request (HARQ) retransmissions over the radio if the UE 502 is in poor radio conditions for example. For wired interfaces, the variation in transmission delay may be due to congestion in the network.

[0063] The first and second gNB 506, 514 may be configured to detect the type of transmission received or transmitted by the respective gNB (such as whether the transmission is a GBR or non-GBR transmission). For example, the first and second gNB 506, 514 may receive Allocation Retention Parameters (ARP) along with other QoS parameters from an AMF (not shown) in the core network 510 during the establishment of the MA-PDU session. The first and second gNB 506, 514 may prepare UE 502 context after the MA-PDU session has been established. Therefore, based on the UE 502 context and ARP parameters, the first and second gNB 506, 514 are able to detect the type of transmission received or transmitted by the respective gNB 506, 514. Accordingly, for example, when the first communications path is being used for the transmission of data, the first gNB 506 is able to detect the type of transmission being transmitted or received by the first gNB 506.

[0064] Phase 2 is a schematic representation immediately after the UPF(PSA) and / or the UE 502 has decided to switch the path used for communications with the core network 510 from the first communications path to the second communications path. The decision to perform the path switch may be based on one or more ATSSS rules. Since first gNB 506 is unaware that the UPF(PSA) and / or the UE 502 has decided to perform a path switch, the UE 502 remains in the RRC connected state for communications via the first gNB 506, even though no communication is occurring via the first communications path in the MA-PDU session due to the path switch. According to existing scenarios, the first gNB 506 implements a timer comprising a pre-defined time period. The timer may be an inactivity timer. For example, the first gNB 506 may restart a timer every time a PDU is received by the first gNB 506 along the first communications path. If no PDU is detected before the timer expires, then the first gNB 506 transmits an RRC release message to the UE 502 indicating to the UE 502 to switch to an RRC inactive state for communications via the first gNB 506. Alternatively, the first gNB 506 may transmit an RRC Release message to the UE 502 indicating to the UE 502 to switch to an RRC idle state for communications via the first gNB 506. The presence of a “suspend configuration” indication in the RRC Release message may indicate to the UE 502 to switch to an RRC inactive state for communications via the first gNB 506 whereas the absence of a “suspend configuration” indication in the RRC Release message may indicate to the UE 502 to switch to an RRC idle state for communications via the first gNB 506. RRC states for a UE are described in more detail with respect to Figure 11 in the Annex. Phase 3 of Figure 7 is a schematic representation after the pre-defined timer has expired and the first gNB 506 has transitioned the UE 502 to the RRC inactive state for communications via the first gNB 506. In Phase 3, the UE 502 and the core network 510 communicate in the MA-PDU session via the second communications path. The UE 502 knows the one or more ATSSS rules used by the core network 510 to perform the path switch. Therefore, the UE 502 determines, based on the one or more ATSSS rules, to transmit uplink transmissions via the second communications paths.

[0065] Since the first gNB 506 is not aware that the communications path has been switched until after the expiry of the pre-defined timer, there is some delay between the switching of the communications paths by the UPF(PSA) and the transitioning of the UE 502 into the RRC inactive state for communications via the first gNB 506. The UE 502 remains in the RRC connected state until it is transitioned into the RRC inactive or RRC idle state. As will be understood by a person skilled in the art, the operation of a UE in the RRC connected state consumes more power than the operation of a UE in the RRC inactive or RRC idle state. Therefore, the delay between the switching of the communications paths and the transitioning of the UE into the RRC inactive state causes power wastage.

[0066] There is therefore a need for methods, communications devices, infrastructure equipment and core network apparatus which can reduce communications device power wastage.

[0067] ATSSS Steering Modes and Rules

[0068] As will be understood by one skilled in the art, a “Steering Mode” identifies how a service data flow (SDF) should be steered between 3GPP and non-3GPP access networks. ATSSS rules may be provided to one or both of a UE and a UPF(PSA) of a core network. As will be understood by one skilled in the art, an SDF flow is a flow of packets representing a service being delivered to a subscriber. The following Steering Modes are currently supported [1]:

[0069] - Active-Standby. According to this steering mode, an SDF is steered on one access network (the “Active” access network) when this access network is available, and the SDF is switched to another access network (the “Standby” access network) when the active access network becomes unavailable. When the active access network becomes available again, the SDF is switched back to the active access network. If the Standby access network is not defined, then the SDF is only allowed on the active access network and cannot be transferred to another access network.

[0070] - Smallest Delay. According to this steering mode, SDF is steered on the access network that is determined to have the smallest Round-Trip Time (RTT). Measurements may be conducted to determine the RTT over a 3GPP access network and over a non-3GPP access network.

[0071] - Load-Balancing. According to this steering mode, an SDF is split across both access networks. With a 50-50 load-balancing, the SDF traffic is equally split across the two access networks. With an 80-20 load-balancing, about 80% of the SDF traffic is sent on one access network and 20% on the other access network.

[0072] - Priority-based. According to this steering mode, SDF is steered using only a high priority access network until a congestion arises on the corresponding interface and, when the high priority access network is congested, additionally using a low priority access network by splitting the SDF over the two access networks. In addition, when the high priority access network becomes unavailable, all traffic is switched to the low priority access network. How UE and UPF(PSA) determine when a congestion occurs on an interface is implementation dependent.

[0073] Examples of existing ATSSS rules based on steering modes are described below: a) "Traffic Descriptor: UDP, DestAddr 1.2.3.4", "Steering Mode: Active-Standby, Active=3GPP, Standby =non-3 GPP " - This ATSS rule can be interpreted as follows: "steer UDP traffic with destination IP address 1.2.3.4 to the active access (3GPP access network), if available. If the active access network is not available, use the standby access (non-3GPP access network)". b) "Traffic Descriptor: TCP, DestPort 8080", "Steering Mode: Smallest Delay"

[0074] - This ATSS rule can be interpreted as follows: "steer TCP traffic with destination port 8080 to the access network with the smallest delay" . The UE may occasionally measure the RTT over both access network, in order to determine which access network has the smallest delay. c) "Traffic Descriptor: Application- 1", "Steering Mode: Load-Balancing, 3GPP=20%, non- 3GPP=80%", "Steering Function: MPTCP"

[0075] - This ATSS rule can be interpreted as follows: "send 20% of the traffic of Application-1 to 3GPP access network and 80% to non-3GPP access network by using MPTCP". d) "Traffic Descriptor: TCP, DestDomain Dreamy5G.com", "Steering Mode: Smallest Delay"

[0076] - This ATSS rule can be interpreted as follows: "steer TCP traffic with destination domain "google.com" to the access network with the smallest delay".

[0077] However, as explained above, support for ATSSS currently requires at least one 3GPP access network and at least one non-3GPP access network. In view of the proposal for MA-PDU sessions with two 3GPP networks, there is also need for new ATSSS rules.

[0078] In view of the above, a method of operating infrastructure equipment of a radio access network of a wireless communications network is illustrated in Figure 8.

[0079] The method starts in step S 1.

[0080] In step S2, the method comprises receiving an indication that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session. The first communications path is used for communications between a communications device and a core network of the wireless communications network via the infrastructure equipment of the radio access network. The MA-PDU session comprises a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network.

[0081] In some embodiments, the radio access network and the other radio access network may be 3GPP access networks. In such embodiments, the infrastructure equipment of the radio access network and the infrastructure equipment of the other radio access network may each be a gNB.

[0082] In some embodiments, the radio access network may be a 3GPP access network and the other radio access network may be a non-3GPP access network. In such embodiments, the infrastructure equipment of the radio access network may be a gNB and the infrastructure equipment of the other radio access network may be a residential gateway implementing WiFi protocols.

[0083] In some embodiments, the communications device is a UE.

[0084] In some embodiments, the indication that communications are no longer expected on the first communications path is received from the core network. In some embodiments, the indication that communications are no longer expected on the first communications path may be received from a UPF(PSA) of the core network. For example, the indication that communications are no longer expected on the first communications path may be transmitted by the UPF(PSA) to the infrastructure equipment over a user plane link. In some embodiments, the indication that communications are no longer expected on the first communications path may be received from an AMF of the core network. For example, the indication that communications are no longer expected on the first communications path may be transmitted by the UPF(PSA) to the AMF, and the AMF may transmit the indication that communications are no longer expected on the first communications path to the infrastructure equipment over a control plane link.

[0085] Alternatively, or additionally, the indication that communications are no longer expected on the first communications path is received from the communications device. In other words, an indication that communications are no longer expected on the first communications path may be received from one or both of the communications device and the core network. In some embodiments, the infrastructure equipment does not transmit the inactive state indication unless it receives an indication that communications are no longer expected on the first communications path from both the communications device and the core network. In some embodiments, the indication received from the core network indicates specifically that downlink communications are not expected on the first communications path and the indication from the communications device indicates specifically that uplink communications are not expected on the first communications path.

[0086] In some embodiments, the communication device may have some knowledge of expected traffic in the near future. In some embodiments, the indication that communications are no longer expected on the first communications path may be received by the infrastructure equipment from the communications device using MAC signalling such as Access Stratum Release Assistance Indication (AS RAI) for MTC / NB- loT. Then, the infrastructure equipment forwards the indication to the UPF(PSA). For example, if the indication in AS RAI is “No subsequent DL and UL data transmission is expected”, the infrastructure equipment can be aware of traffic inactivity in near future.

[0087] In some embodiments, the indication that communications are no longer be expected on the first communications path may be comprised in a downlink channel quality report (DCQR). The UE may transmit the DCQR to the gNB via a MAC layer. An example of such a DCQR is discussed in TS36.321 vl6.8.0, the contents of which are hereby incorporated by reference in their entirety.

[0088] In some embodiments, the indication that communications are no longer expected on the first communication path may additionally include time information indicating a time period for which communications are not expected on the first communications path. The time period may be determined by the core network based on a data traffic prediction.

[0089] In some embodiments, the indication that communications are no longer expected on the first communications path is an implicit indication. For example, the communications device may transmit an indication that the second communications path is being used for communications between the communications device and the core network via the infrastructure equipment of the other radio access network. In this case, the infrastructure equipment of the radio access network may determine, based on this indication, that the communications path has been switched from the first communications path to the second communications path. In another example of an implicit indication, the indication that communications are no longer expected on the first communications path comprises an indication of radio conditions experienced by the communications device on the first communications path. Based on the indicated radio conditions, the infrastructure equipment of the radio access network may determine that communications are no longer expected on the first communications path. The indication of the radio conditions may be included in UE assistance information, UAI.

[0090] In another example of an implicit indication, the indication that communications are no longer expected on the first communications path comprises an indication of mobility conditions experienced by the communications device on the first communications path. For example, if the communications device is stationary and the radio coverage from the second communication path is above a threshold, the infrastructure equipment of the radio access network may determine that communications are no longer expected on the first communications path. The communications device may indicate a current mobility state (e.g., high speed mobility like vehicle, low speed mobility like pedestrian, stationary) of the communication device with assistance information to the infrastructure equipment. Alternatively, or additionally, a location management function (LMF) in the core network may indicate the mobility status of the communication device to the infrastructure equipment. Otherwise, the infrastructure equipment of the radio access network may indirectly estimate the mobility status of the communication device based on one or more of measurement reports for handover, changes of timing advance and so on.

[0091] In step S3, the method comprises, in response to receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session, transmitting an inactive state indication to the communications device. The inactive state indication indicates to the communications device to transition to an inactive state for communications with the infrastructure equipment of the radio access network.

[0092] The inactive state may be, for example, an RRC inactive or RRC idle state.

[0093] In some embodiments the infrastructure equipment of the radio access network may determine that the first communications path will not be used for communications for longer than a pre-defined time limit. For example, the indication received from the communications or the core network that communications are no longer expected on the first communications path may include an indication that the first communications path will not be used for longer than a pre-defined time limit. In such cases, the infrastructure equipment may transmit an indication to the communications device to transition the communications device into the RRC idle state for communications with the infrastructure equipment of the radio access network. In this case, the infrastructure equipment of the access network sends an indication to the core network that it has transitioned the communications device to the RRC idle state.

[0094] The method ends in step S4.

[0095] Therefore, embodiments can enable infrastructure equipment of a radio access network to dynamically indicate to a communications device to transition to an inactive state for communications with that infrastructure equipment in response to an indication that communications via that infrastructure equipment are no longer expected. The communications device can be transitioned into an inactive state without relying on the expiry of a pre-determined timer and embodiments can therefore enable the transition to occur more quickly. Therefore, the communications device spends less time in a connected state and accordingly uses less power and reduces reserved radio resources compared to connected mode.

[0096] Although power consumption of the communications device may be reduced by configuring a shorter value for the pre-determined timer (because the communications device would spend less time in the connected state), this may increase the signalling load of state transition between active and inactive (including idle). As will be appreciated by one skilled in the art, this is a waste of radio resources and involves an unnecessarily high load of control plane in the radio access network (RAN). Figure 9 illustrates a method of operating a core network apparatus of a wireless communications network in accordance with example embodiments.

[0097] The core network apparatus may be a UPF (PSA) or AMF, for example.

[0098] The method starts in step S10.

[0099] In step S20, the method comprises determining that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session. The first communications path is used for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network. The MA- PDU session comprises a second communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network

[0100] In some embodiments, the core network apparatus receives, from the infrastructure equipment of the radio access network, a tolerable uplink jitter range and one or more uplink jitter measurements, and determining that at least one of the one or more uplink jitter measurements falls outside the tolerable uplink j itter range .

[0101] In some embodiments, the radio access network is a 3GPP access network and the other radio access network is another 3GPP access network. The one or more ATSSS rules may comprise a rule indicating that communications should occur via the 3GPP access network if available and via the other 3GPP access network if the 3GPP access network is not available. In some embodiments, the 3GPP access network is comprised in a terrestrial network, TN, and the other 3GPP access network is comprised in a non-terrestrial network NTN. In other embodiments, the 3GPP access network is comprised in a standalone non-public network, SNPN, and the other 3GPP access network is comprised a public land mobile network, PLMN.

[0102] Examples of ATSSS rules which may be used in accordance with example embodiments are shown in a) and b) below. a) "Traffic Descriptor: UDP, DestAddr 1.2.3.4", "Steering Mode: Active-Standby, Active=TN, Standby=NTN" .

[0103] This ATSSS rule can be interpreted as "steer UDP traffic with destination IP address 1.2.3.4 to the active access (TN), if available. If the active access is not available, use the standby access (NTN)". b) "Traffic Descriptor: UDP, DestAddr 1.2.3.4", "Steering Mode: Active-Standby, Active=SNPN, Standby=PEMN" .

[0104] This ATSSS rule can be interpreted as "steer UDP traffic with destination IP address 1.2.3.4 to the active access network (SNPN), if available. If the active access network is not available, use the standby access network (PEMN)".

[0105] In some embodiments, one or more of the ATSSS rules may specify how to transmit uplink data and one or more others of the ATSSS rules may specify how to transmit downlink data. In step S30, the method comprises, in response, transmitting an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session.

[0106] The method ends in step S40.

[0107] An example of transitioning a communications device to an inactive state for a communications path in an MA-PDU session in accordance with a received indication is described in connection with Figure 10.

[0108] In Figure 10, the UE 502 may have two AS layer protocol stacks and is connected to two gNBs, namely, a first gNB 506 and a second gNB 514. The first gNB 506 and the second gNB 514 may be part of an NTN and TN respectively (or vice versa), or part of PLMN and SNPN respectively (or vice versa). Phase 1 and Phase 2 of Figure 10 broadly correspond to Phase 1 and Phase 2 of Figure 7, and so the description of Phase 1 and Phase 2 will not be repeated for brevity.

[0109] As explained above with reference to Figure 7, after the UPF(PSA) has performed the path switch based on one or more ATSSS rules, the UE 502 remains in a connected state (such as an RRC connected state) for communications via the first gNB 506, even though no communications are occurring via the first communications path in the MA-PDU session. However, in contrast to Figure 7, the UPF(PSA), in response to the path switch, transmits a path switch indication to the UE 502 indicating that the communications path used for communications in the MA-PDU session has switched from the first communications path to the second communication path. In other embodiments, the UE 502 may transmit the path switch indication to the first gNB 506. For example, the UE 502 may know the one or more ATSSS rules and determine based on the one or more ATSSS rules that the path switch has occurred.

[0110] In response to receiving the path switch indication, the first gNB 506 transmits an inactive state indication to the UE 502 indicating to the UE 502 to transition to an inactive state for communications with the first gNB 506. For example, the first gNB 506 may transmit an RRC release message to the UE 502 indicating to the UE 502 to switch to an RRC inactive state for communications via the first gNB 506. Alternatively, the first gNB 506 may transmit an RRC Release message to the UE 502 indicating to the UE to switch to an RRC idle state for communications via the first gNB 506.

[0111] Although in the description of Figure 10, the UE 502 or UPF(PSA) transmits a path switch indication to the first gNB 506, the path switch indication is one example of a more general indication that communications are no longer expected on the first communications path. In some embodiments, the UE 502 may be in an inactive state for communications via the second communications path and in a connected state for communications via the first communications path. However, the UPF(PSA) and / or UE 502 may determine that communications are not expected on the first communications path for reasons other than a path switch. For example, the UE 502 and / or UPF(PSA) may detect that no communications have occurred on the first communications path for a pre-determined time period. In this case, the UE 502 and / or UPF(PSA) may transmit an indication to the first gNB 506 indicating to the UE 502 to transition to an inactive state for communications via the first communications path. Therefore, scenarios can arise where the UE 502 is in an inactive state for communications via the first communications path and for communications via the second communications path.

[0112] Therefore, embodiments can provide a means for dynamically indicating to a communications device to transition to an inactive state in response to an indication that communications are no longer expected on the first communications path. Therefore, the UE 502 can spend less time in a connected mode with the first gNB 506 than if a pre-defined timer were used, and power is accordingly saved.

[0113] As described with reference to Phase 1 of Figures 7 and 10, the UE 502 may be in an RRC connected (with no current traffic on the second communications path), RRC inactive or RRC idle state for communications via the second gNB 514. In cases where the UE 502 is in an RRC inactive or RRC idle state for communications via the second gNB 514 in Phase 1, the UE 502 may need to transition to the RRC connected state for communications via the second gNB 514 in order to be able to communicate via the second communications path in Phases 2 and 3. As described below, example embodiments can provide a fast and efficient transition of the UE 502 to the RRC connected mode when a path switch occurs.

[0114] Embodiments can provide a method of operating infrastructure equipment of a radio access network of a wireless communications network. The method comprises receiving, from a core network of the wireless communications network, an indication that communications are expected on a second communications path of a multi-access protocol data unit, MA-PDU, session, the second communications path being for communications between a communications device and the core network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network. In response to receiving the indication that communications are expected on the first communications path of the MA-PDU session, the method comprises transmitting a connected state indication to the communications device, the connected state indication indicating to the communications device to transition to a connected state for communications with the infrastructure equipment of the radio access network.

[0115] By receiving an indication that communications are expected on the second communications path, the infrastructure equipment can dynamically transition the communications device to the connected state (from the inactive or idle state) in response to receiving the indication. Therefore, the communications device can be transitioned to the connected state quicker than if such an indication were not received.

[0116] With reference to Figure 10, for example, the core network 510 may transmit the connected state indication to the second gNB 514 in response to the core network 510 determining that communications are expected on the second communications path via the second gNB 514. In some embodiments, the determination that communications are expected on the second communications path, and the transmission of the connected state indication, may be performed by a UPF(PSA) in the core network.

[0117] In some embodiments, the core network (e.g. a UPF(PSA) of the core network) may determine both that communications are no longer expected on the first communications path and that communications are expected on the second communications path. In response, the core network may transmit an indication to the infrastructure equipment of the radio access network on the first communications path indicating that communications are no longer expected on the first communications path and an indication to the infrastructure equipment of another radio access network on the second communications path indicating that communications are expected on the second communications path.

[0118] The following numbered paragraphs provide further example aspects and features of the present technique:

[0119] Paragraph 1. A method of operating infrastructure equipment of a radio access network of a wireless communications network, the method comprising receiving an indication that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and a core network of the wireless communications network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session, transmitting an inactive state indication to the communications device, the inactive state indication indicating to the communications device to transition to an inactive state for communications with the infrastructure equipment of the radio access network.

[0120] Paragraph 2. A method according to paragraph 1, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from the core network.

[0121] Paragraph 3. A method according to paragraph 2, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from the core network comprises receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from a user plane function, UPF, of the core network.

[0122] Paragraph 4. A method according to paragraph 2, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from the core network comprises receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from an Access Mobility and Management, AMF, function of the core network.

[0123] Paragraph 5. A method according to any of paragraphs 1 to 4, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from the communications device, or receiving another indication that communications are no longer expected on the first communications path of the MA-PDU session from the communications device.

[0124] Paragraph 6. A method according to paragraph 5, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving an indication that the second communications path is currently being used for communications between the communications device and the core network via the infrastructure equipment of the other radio access network.

[0125] Paragraph 7. A method according to paragraph 5 or paragraph 6, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving an indication of radio conditions experienced by the communications device on the first communications path.

[0126] Paragraph 8. A method according to any of paragraphs 1 to 7, comprising receiving, from the communications device, a tolerable uplink jitter range, performing one or more of uplink jiter measurements, the one or more uplink jiter measurements being for comparison with the tolerable uplink j itter range to determine if the one or more uplink jiter measurements fall within the tolerable uplink jiter range, transmiting the tolerable uplink jiter range and the one or more uplink jiter measurements to the core network.

[0127] Paragraph 9. A method according to any of paragraphs 1 to 8, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving a path switch indication indicating that that a communications path used for communications between the communications device and the core network in the MA-PDU session has been switched from the first communications path to the second communication path.

[0128] Paragraph 10. A method according to any of paragraphs 1 to 9, wherein the inactive state is an RRC inactive state and the inactive state indication is comprised in an RRC Release message.

[0129] Paragraph 11. A method according to any of paragraphs 1 to 9, wherein the inactive state is an RRC idle state and the inactive state indication is comprised in an RRC Release message.

[0130] Paragraph 12. A method of operating a core network apparatus of a wireless communications network, the method comprising determining that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, transmiting an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session. Paragraph 13. A method according to paragraph 12, wherein the determining that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving, from the infrastructure equipment of the radio access network, a tolerable uplink jiter range and one or more uplink jiter measurements, and determining that at least one of the one or more uplink jiter measurements falls outside the tolerable uplink jiter range.

[0131] Paragraph 14. A method according to any of paragraphs 12 or 13, wherein the determining that communications are no longer expected on the first communications path of the MA-PDU session comprises determining, based on one or more access traffic steering, switching and spliting, ATSSS rules, to switch a communications path used for communications between the communications device and the core network apparatus in the MA-PDU session from the first communications path to the second communications path, and the transmiting the indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session comprises transmiting a path switch indication to the infrastructure equipment indicating that the communications path used for communications between the communications device and the core network has been switched from the first communications path to the second communications path.

[0132] Paragraph 15. A method according to paragraph 14, wherein the radio access network is a 3GPP access network and the other radio access network is another 3GPP access network, and the one or more ATSSS rules comprise a rule indicating that communications should occur via the infrastructure equipment of the 3GPP access network if available and via the infrastructure equipment of the other 3GPP access network if the infrastructure equipment of the 3GPP access network is not available.

[0133] Paragraph 16. A method according to paragraph 15, wherein the 3GPP access network is comprised in a terrestrial network, TN, and the other 3GPP access network is comprised in a non-terrestrial network NTN.

[0134] Paragraph 17. A method according to paragraph 15, wherein the 3GPP access network is comprised in a stand-alone non-public network, SNPN, and the other 3GPP access network is comprised in a public land mobile network, PLMN.

[0135] Paragraph 18. A method of operating communications device, the method comprising determining that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between the communications device and a core network of a wireless communications network via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response, transmitting an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session. Paragraph 19. A method according to paragraph 18, wherein the determining that communications are no longer expected on the first communications path of the MA-PDU session comprises determining, based on one or more access traffic steering, switching and splitting, ATSSS rules, to switch a communications path used for communications between the communications device and the core network apparatus in the MA-PDU session from the first communications path to the second communications path, and the transmitting the indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session comprises transmitting a path switch indication to the infrastructure equipment indicating that the communications path used for communications between the communications device and the core network has been switched from the first communications path to the second communications path.

[0136] Paragraph 20. A method according to paragraph 19, wherein the radio access network is a 3GPP access network and the other radio access network is another 3GPP access network, and the one or more ATSSS rules comprise a rule indicating that communications should occur via the infrastructure equipment of the 3GPP access network if available and via the infrastructure equipment of the other 3GPP access network if the infrastructure equipment of the 3GPP access network is not available.

[0137] Paragraph 21. A method according to paragraph 20, wherein the 3GPP access network is comprised in a terrestrial network, TN, and the other 3GPP access network is comprised in a non-terrestrial network NTN.

[0138] Paragraph 22. A method according to paragraph 20, wherein the 3GPP access network is comprised in a stand-alone non-public network, SNPN, and the other 3GPP access network is comprised in a public land mobile network, PUMN.

[0139] Paragraph 23. A method of operating infrastructure equipment of a radio access network of a wireless communications network, the method comprising receiving, from a core network of the wireless communications network, an indication that communications are expected on a second communications path of a multi-access protocol data unit, MA- PDU, session, the second communications path being for communications between a communications device and the core network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are expected on the second communications path of the MA-PDU session, transmitting a connected state indication to the communications device, the connected state indication indicating to the communications device to transition to a connected state for communications with the infrastructure equipment of the radio access network.

[0140] Paragraph 24. A method of operating a core network apparatus of a wireless communications network, the method comprising determining that communications are expected on a second communications path of a multiaccess protocol data unit, MA-PDU, session, the second communications path being for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, transmitting an indication to the infrastructure equipment of the radio access network indicating that communications are expected on the second communications path of the MA-PDU session. Paragraph 25. Infrastructure equipment for a radio access network of a wireless communications network, the infrastructure equipment comprising a transmitter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmitter and the receiver to receive an indication that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and a core network of the wireless communications network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session, the controller is configured in combination with the transmitter and the receiver to transmit an inactive state indication to the communications device, the inactive state indication indicating to the communications device to transition to an inactive state for communications with the infrastructure equipment of the radio access network.

[0141] Paragraph 26. Circuitry for infrastructure equipment for a radio access network of a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals, receiver circuitry configured to receive signals, and controller circuitry configured in combination with the transmitter circuitry and the receiver circuitry to receive an indication that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and a core network of the wireless communications network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session, the controller circuitry is configured in combination with the transmitter circuitry and the receiver circuitry to transmit an inactive state indication to the communications device, the inactive state indication indicating to the communications device to transition to an inactive state for communications with the infrastructure equipment of the radio access network.

[0142] Paragraph 27. A core network apparatus for a wireless communications network, the core network apparatus comprising a transmitter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmitter and the receiver to determine that communications are no longer expected on a first communications path of a multiaccess protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller is configured in combination with the transmitter and the receiver to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session. Paragraph 28. Circuitry for a core network apparatus for a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals, receiver circuitry configured to receive signals, and controller circuitry configured in combination with the transmitter circuitry and the receiver circuitry to determine that communications are no longer expected on a first communications path of a multiaccess protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller circuitry is configured in combination with the transmitter circuitry and the receiver circuitry to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session. Paragraph 29. A communications device comprising a transmitter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmitter and the receiver to determine that communications are no longer expected on a first communications path of a multiaccess protocol data unit, MA-PDU, session, the first communications path being used for communications between the communications device and a core network of a wireless communications network via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller is configured in combination with the transmitter and the receiver to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session. Paragraph 30. Circuitry for a communications device, the circuity comprising transmiter circuitry configured to transmit signals, receiver circuitry configured to receive signals, and controller circuitry configured in combination with the transmiter circuitry and the receiver circuitry to determine that communications are no longer expected on a first communications path of a multiaccess protocol data unit, MA-PDU, session, the first communications path being used for communications between the communications device and a core network of a wireless communications network via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller circuitry is configured in combination with the transmiter circuitry and the receiver circuitry to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session. Paragraph 31. Infrastructure equipment for a radio access network of a wireless communications network, the infrastructure equipment comprising a transmiter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmiter and the receiver to receive, from a core network of the wireless communications network, an indication that communications are expected on a second communications path of a multi-access protocol data unit, MA- PDU, session, the second communications path being for communications between a communications device and the core network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are expected on the second communications path of the MA-PDU session, the controller is configured in combination with the transmiter and the receiver to transmit a connected state indication to the communications device, the connected state indication indicating to the communications device to transition to a connected state for communications with the infrastructure equipment of the radio access network.

[0143] Paragraph 32. Circuitry for infrastructure equipment for a radio access network of a wireless communications network, the circuitry comprising transmiter circuitry configured to transmit signals, receiver circuitry configured to receive signals, and controller circuitry configured in combination with the transmiter circuitry and the receiver circuitry to receive, from a core network of the wireless communications network, an indication that communications are expected on a second communications path of a multi-access protocol data unit, MA- PDU, session, the second communications path being for communications between a communications device and the core network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are expected on the second communications path of the MA-PDU session, the controller circuitry is configured in combination with the transmiter circuitry and the receiver circuitry to transmit a connected state indication to the communications device, the connected state indication indicating to the communications device to transition to a connected state for communications with the infrastructure equipment of the radio access network. Paragraph 33. A core network apparatus for a wireless communications network, the core network apparatus comprising a transmitter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmitter and the receiver to determine that communications are expected on a second communications path of a multi-access protocol data unit, MA-PDU, session, the second communications path being for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller is configured in combination with the transmitter and the receiver to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are expected on the second communications path of the MA-PDU session.

[0144] Paragraph 34. Circuitry for a core network apparatus for a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals, receiver circuitry configured to receive signals, and controller circuitry configured in combination with the transmitter circuitry and the receiver circuitry to determine that communications are expected on a second communications path of a multi-access protocol data unit, MA-PDU, session, the second communications path being for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller circuitry is configured in combination with the transmitter circuitry and the receiver circuitry to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are expected on the second communications path of the MA-PDU session.

[0145] Paragraph 35. A wireless communications network comprising infrastructure equipment according to paragraph 25, a core network apparatus according to paragraph 27 and a communications device according to paragraph 29.

[0146] Paragraph 36. A computer program comprising instructions which, when program is executed by a computer, cause the computer perform the method of any of paragraphs 1 to 24.

[0147] Paragraph 37. A non-transitory computer-readable storage medium storing a computer program according to paragraph 36.

[0148] 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.

[0149] ANNEX

[0150] As shown in Figure 11, a UE may occupy one of three Radio Resource Control (RRC) states: the RRC_CONNECTED state 706 (referred to herein as the “connected state”), the RRC_INACTIVE state 710 (referred to herein as the “inactive state”) and the RRC_IDLE 702 state (referred to herein as the “idle state”).

[0151] In the idle state 702, the UE does not have dedicated resources and does not transmit or receive user data apart from performing actions necessary to manage its own mobility. The UE also performs monitoring for paging by monitoring broadcast signals transmitted on a Broadcast Control Channel (BCCH) by each gNB. The core network is aware of the UE’s location within a Tracking Area and does not have the UE AS (access stratum) context and cannot schedule physical resources for user data transmission because the UE does not have a unique identifier within a cell (C-RNTI).

[0152] In the connected state 702, the UE has established an RRC connection and has dedicated resources for transmitting or receiving data. The core network is aware of the UE’s location at the cell level and has the UE context thereby allowing scheduling of physical resources for user data transmissions because the UE has been assigned a temporary ID which is unique to that UE within the cell (C-RNTI) and hence the UE can be directly addressed by the core network.

[0153] In the inactive state 710, the UE can perform small data transmission (SDT) with the wireless communication network. The core network will not be aware that the UE is in the inactive state and will therefore not release any tunnels which have been established between the UE and the core network when the UE was in the connected state 706.

[0154] In the inactive state 710, the UE retains access stratum (AS) context. Storing of AS context in the UE is specified in [4] as:

[0155] “Store in the UE Inactive AS Context the current KgNB and KRRCint keys, the ROHC state, the stored QoS flow to DRB mapping rules, the C-RNTI used in the source PCell, the cellldentity and the physical cell identity of the source PCell, the spCellConfigCommon within ReconfigurationWithSync of the NR PSCell (if configured) and all other parameters configured except for: parameters within ReconfigurationWithSync of the PCell; parameters within ReconfigurationWithSync of the NR PSCell, if configured; parameters within MohilityControlInfoSCG of the E-UTRA PSCell, if configured; servingCellConfigCommonSIB. ”

[0156] Figure 11 illustrates how a UE may transition between the idle 702, inactive 710 and connected 706 states. If a UE in the idle state 702 establishes an RRC connection, the UE transitions from the idle 702 to the connected state 706 as shown by arrow 716. Conversely, a UE may transition from the connected state 706 to the idle state 702 by releasing its RRC connection (and hence releasing its C-RNTI) as shown by arrow 718.

[0157] A UE may transition from the connected state 706 to the inactive state if it receives an RRC suspend configuration message in an RRC Release message as shown by arrow 712. In this case, although the radio link between the UE and the base station in the connected state 706 is taken down for power conservation, the logical link to the Access Mobility and Management function (AMF) in the core network and the user data tunnel to the UPF remain in place. The core network is not aware that an inactive state exists for the UE and treats the UE as if it were in the connected state 706.

[0158] A UE transition from the inactive state 710 to the connected state 706 via a resume procedure as shown by arrow 714. A UE may initiate an RRC resume procedure to resume a previously suspended RRC connection. Specifically, the UE may resume SRB(s) or DRB(s) or perform an RNA update. Further details on the resume procedure may found in pending international application PCT / EP2022 / 051040, published as WO 2022 / 167216, which is hereby incorporated by reference in its entirety

[0159] It is advantageous for a UE to remain in an inactive state where there is no immediate traffic between the UE and the core network but there is likely to be so in the near future. As the UE in the inactive state retains AS context as explained above, the transition from the inactive state to the connected state quicker than the transition from the idle state to the connected state.

[0160] References:

[0161] [1] 3GPP TR 23.793 V16.0.0 (2018-12), “Study on access traffic steering, switch and splitting support in the 5G System (5GS) architecture”, 3rd Generation Partnership Project.

[0162] [2] 3GPP Technical Specification #23.501, V18.2.1, “System architecture for the 5G System (5GS);Stage 2”.

[0163] [3] 3GPP Technical Specification #24. 193, V0.1.0, “Technical Specification Group Core Network and Terminals; Access Traffic Steering, Switching and Splitting; Stage 3”. [4] 3GPP TS 38.331 section 5.3.8.3, “Radio Resource Control (RRC) Specification”, 3rd Generation

[0164] Partnership Project.

Claims

CLAIMS1. A method of operating infrastructure equipment of a radio access network of a wireless communications network, the method comprising receiving an indication that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and a core network of the wireless communications network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session, transmitting an inactive state indication to the communications device, the inactive state indication indicating to the communications device to transition to an inactive state for communications with the infrastructure equipment of the radio access network.

2. A method according to claim 1, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from the core network.

3. A method according to claim 2, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from the core network comprises receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from a user plane function, UPF, of the core network.

4. A method according to claim 2, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from the core network comprises receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from an Access Mobility and Management, AMF, function of the core network.

5. A method according to claim 1, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session from the communications device, or receiving another indication that communications are no longer expected on the first communications path of the MA-PDU session from the communications device.

6. A method according to claim 5, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving an indication that the second communications path is currently being used for communications between the communications device and the core network via the infrastructure equipment of the other radio access network.

7. A method according to claim 5, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving an indication of radio conditions experienced by the communications device on the first communications path.

8. A method according to claim 1, comprising receiving, from the communications device, a tolerable uplink jitter range, performing one or more of uplink jitter measurements, the one or more uplink jitter measurements being for comparison with the tolerable uplink jitter range to determine if the one or more uplink jitter measurements fall within the tolerable uplink jitter range, transmitting the tolerable uplink jitter range and the one or more uplink jitter measurements to the core network.

9. A method according to claim 1, wherein the receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving a path switch indication indicating that that a communications path used for communications between the communications device and the core network in the MA-PDU session has been switched from the first communications path to the second communication path.

10. A method according to claim 1, wherein the inactive state is an RRC inactive state and the inactive state indication is comprised in an RRC Release message.

11. A method according to claim 1, wherein the inactive state is an RRC idle state and the inactive state indication is comprised in an RRC Release message.

12. A method of operating a core network apparatus of a wireless communications network, the method comprising determining that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, transmitting an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session.

13. A method according to claim 12, wherein the determining that communications are no longer expected on the first communications path of the MA-PDU session comprises receiving, from the infrastructure equipment of the radio access network, a tolerable uplink jitter range and one or more uplink jitter measurements, and determining that at least one of the one or more uplink jitter measurements falls outside the tolerable uplink jitter range.

14. A method according to claim 12, wherein the determining that communications are no longer expected on the first communications path of the MA-PDU session comprises determining, based on one or more access traffic steering, switching and splitting, ATSSS rules, to switch a communications path used for communications between the communications device and thecore network apparatus in the MA-PDU session from the first communications path to the second communications path, and the transmitting the indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session comprises transmitting a path switch indication to the infrastructure equipment indicating that the communications path used for communications between the communications device and the core network has been switched from the first communications path to the second communications path.

15. A method according to claim 14, wherein the radio access network is a 3GPP access network and the other radio access network is another 3GPP access network, and the one or more ATSSS rules comprise a rule indicating that communications should occur via the infrastructure equipment of the 3GPP access network if available and via the infrastructure equipment of the other 3GPP access network if the infrastructure equipment of the 3GPP access network is not available.

16. A method according to claim 15, wherein the 3GPP access network is comprised in a terrestrial network, TN, and the other 3GPP access network is comprised in a non-terrestrial network NTN.

17. A method according to claim 15, wherein the 3 GPP access network is comprised in a stand-alone non-public network, SNPN, and the other 3GPP access network is comprised in a public land mobile network, PLMN.

18. A method of operating communications device, the method comprising determining that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between the communications device and a core network of a wireless communications network via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response, transmitting an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session.

19. A method according to claim 18, wherein the determining that communications are no longer expected on the first communications path of the MA-PDU session comprises determining, based on one or more access traffic steering, switching and splitting, ATSSS rules, to switch a communications path used for communications between the communications device and the core network apparatus in the MA-PDU session from the first communications path to the second communications path, and the transmitting the indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session comprises transmitting a path switch indication to the infrastructure equipment indicating that the communications path used for communications between the communications device and the core network has been switched from the first communications path to the second communications path.

20. A method according to claim 19, wherein the radio access network is a 3GPP access network and the other radio access network is another 3GPP access network, and the one or more ATSSS rules comprise a rule indicating that communications should occur via the infrastructure equipment of the 3GPP access network if available and via the infrastructure equipment of the other 3GPP access network if the infrastructure equipment of the 3GPP access network is not available.

21. A method according to claim 20, wherein the 3GPP access network is comprised in a terrestrial network, TN, and the other 3GPP access network is comprised in a non-terrestrial network NTN.

22. A method according to claim 20, wherein the 3GPP access network is comprised in a stand-alone non-public network, SNPN, and the other 3GPP access network is comprised in a public land mobile network, PLMN.

23. A method of operating infrastructure equipment of a radio access network of a wireless communications network, the method comprising receiving, from a core network of the wireless communications network, an indication that communications are expected on a second communications path of a multi-access protocol data unit, MA- PDU, session, the second communications path being for communications between a communications device and the core network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are expected on the second communications path of the MA-PDU session, transmitting a connected state indication to the communications device, the connected state indication indicating to the communications device to transition to a connected state for communications with the infrastructure equipment of the radio access network.

24. A method of operating a core network apparatus of a wireless communications network, the method comprising determining that communications are expected on a second communications path of a multiaccess protocol data unit, MA-PDU, session, the second communications path being for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, transmitting an indication to the infrastructure equipment of the radio access network indicating that communications are expected on the second communications path of the MA-PDU session.

25. Infrastructure equipment for a radio access network of a wireless communications network, the infrastructure equipment comprising a transmitter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmitter and the receiver to receive an indication that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and a core network of the wireless communications network via the infrastructure equipment of the radio access network, the MA-PDU session comprising asecond communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session, the controller is configured in combination with the transmitter and the receiver to transmit an inactive state indication to the communications device, the inactive state indication indicating to the communications device to transition to an inactive state for communications with the infrastructure equipment of the radio access network.

26. Circuitry for infrastructure equipment for a radio access network of a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals, receiver circuitry configured to receive signals, and controller circuitry configured in combination with the transmitter circuitry and the receiver circuitry to receive an indication that communications are no longer expected on a first communications path of a multi-access protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and a core network of the wireless communications network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are no longer expected on the first communications path of the MA-PDU session, the controller circuitry is configured in combination with the transmitter circuitry and the receiver circuitry to transmit an inactive state indication to the communications device, the inactive state indication indicating to the communications device to transition to an inactive state for communications with the infrastructure equipment of the radio access network.

27. A core network apparatus for a wireless communications network, the core network apparatus comprising a transmitter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmitter and the receiver to determine that communications are no longer expected on a first communications path of a multiaccess protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller is configured in combination with the transmitter and the receiver to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session.

28. Circuitry for a core network apparatus for a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals, receiver circuitry configured to receive signals, andcontroller circuitry configured in combination with the transmitter circuitry and the receiver circuitry to determine that communications are no longer expected on a first communications path of a multiaccess protocol data unit, MA-PDU, session, the first communications path being used for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller circuitry is configured in combination with the transmitter circuitry and the receiver circuitry to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session.

29. A communications device comprising a transmitter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmitter and the receiver to determine that communications are no longer expected on a first communications path of a multiaccess protocol data unit, MA-PDU, session, the first communications path being used for communications between the communications device and a core network of a wireless communications network via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller is configured in combination with the transmitter and the receiver to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session.

30. Circuitry for a communications device, the circuity comprising transmitter circuitry configured to transmit signals, receiver circuitry configured to receive signals, and controller circuitry configured in combination with the transmitter circuitry and the receiver circuitry to determine that communications are no longer expected on a first communications path of a multiaccess protocol data unit, MA-PDU, session, the first communications path being used for communications between the communications device and a core network of a wireless communications network via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a second communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller circuitry is configured in combination with the transmitter circuitry and the receiver circuitry to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are no longer expected on the first communications path of the MA-PDU session.

31. Infrastructure equipment for a radio access network of a wireless communications network, the infrastructure equipment comprising a transmitter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmitter and the receiver toreceive, from a core network of the wireless communications network, an indication that communications are expected on a second communications path of a multi-access protocol data unit, MA- PDU, session, the second communications path being for communications between a communications device and the core network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are expected on the second communications path of the MA-PDU session, the controller is configured in combination with the transmitter and the receiver to transmit a connected state indication to the communications device, the connected state indication indicating to the communications device to transition to a connected state for communications with the infrastructure equipment of the radio access network.

32. Circuitry for infrastructure equipment for a radio access network of a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals, receiver circuitry configured to receive signals, and controller circuitry configured in combination with the transmitter circuitry and the receiver circuitry to receive, from a core network of the wireless communications network, an indication that communications are expected on a second communications path of a multi-access protocol data unit, MA- PDU, session, the second communications path being for communications between a communications device and the core network via the infrastructure equipment of the radio access network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network via infrastructure equipment of another radio access network of the wireless communications network, and in response to receiving the indication that communications are expected on the second communications path of the MA-PDU session, the controller circuitry is configured in combination with the transmitter circuitry and the receiver circuitry to transmit a connected state indication to the communications device, the connected state indication indicating to the communications device to transition to a connected state for communications with the infrastructure equipment of the radio access network.

33. A core network apparatus for a wireless communications network, the core network apparatus comprising a transmitter configured to transmit signals, a receive configured to receive signals, and a controller configured in combination with the transmitter and the receiver to determine that communications are expected on a second communications path of a multi-access protocol data unit, MA-PDU, session, the second communications path being for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller is configured in combination with the transmitter and the receiver to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are expected on the second communications path of the MA-PDU session.

34. Circuitry for a core network apparatus for a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals, receiver circuitry configured to receive signals, and controller circuitry configured in combination with the transmitter circuitry and the receiver circuitry to determine that communications are expected on a second communications path of a multi-access protocol data unit, MA-PDU, session, the second communications path being for communications between a communications device and the core network apparatus via infrastructure equipment of a radio access network of the wireless communications network, the MA-PDU session comprising a first communications path for communications between the communications device and the core network apparatus via infrastructure equipment of another radio access network of the wireless communications network, and in response, the controller circuitry is configured in combination with the transmitter circuitry and the receiver circuitry to transmit an indication to the infrastructure equipment of the radio access network indicating that communications are expected on the second communications path of the MA-PDU session.

35. A wireless communications network comprising infrastructure equipment according to claim 25, a core network apparatus according to claim 27 and a communications device according to claim 29.

36. A computer program comprising instructions which, when program is executed by a computer, cause the computer perform the method of claim 1.

37. A non-transitory computer-readable storage medium storing a computer program according to claim 36.

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