Methods, communications devices, and infrastructure equipment

Abstract

A communications device can operate to transmit and to receive via a wireless communications network, by establishing a multi-modal bearer for packets with different QoS requirements. When performing a handover by receiving a handover command to handover from a source base station of the RAN to a target base station of the RAN, communications device the re-configures the multi-modal bearer for the target base station. Reconfiguration can include establishing dedicated radio access bearers with different QoS flows, which are the same as those or different to those, which were provided by the source base station. The communications device adapts each packet to include a time stamp or other indication which can allow a receiver to determine an order of packets with respect to each other, so that a relative order of transmission of the packets or reproduction of packets can be determined to synchronise a relative order of the packets in each different QoS flow of the multimodal bearer. As such during handover different QoS flows can be synchronised because these are more likely to be disrupted by the process of the handover. An infrastructure equipment communicates a multi-modal ID to the core network when acting as a target for handover and communicates the multi-modal ID of a multi-modal bearer, which the infrastructure equipment should support in order to be a handover target to the core network. As such, as part of the reconfiguration of the bearer supporting the multi-modal communication, a path switch is performed in the core network. As part of that path switch process, the multi-modal bearer can be either reconfigured by the target infrastructure equipment or adapted in accordance with the capability of the target infrastructure equipment to support different QoS flows required by the multi-modal bearer.

Description

[0001] METHODS, COMMUNICATIONS DEVICES, AND INFRASTRUCTURE EQUIPMENT

[0002] BACKGROUND

[0003] Field of Disclosure

[0004] The present disclosure relates to methods of operating a communications device to communicate via wireless communications networks, communications devices operating to communicate via wireless communications networks and infrastructure equipment forming part of a wireless communications networks.

[0005] The present application claims the Paris convention priority to European patent application number EP24154023.6 filed on 25 January 2024, the contents of which is incorporated herein by reference in its 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] Current and future wireless communications networks are expected to routinely and efficiently support communications with an ever-increasing range of devices associated with a wider range of data traffic profiles and types than existing systems are optimised to support. For example, it is expected future wireless communications networks will be expected efficiently to support communications with devices including reduced complexity devices, machine type communication (MTC) devices, high resolution video displays, virtual reality headsets, extended Reality (XR) and so on. Some of these different types of devices may be deployed in very large numbers, for example low complexity devices for supporting the “The Internet of Things”, whereas other types of devices, can support high-definition video streaming, may be associated with transmissions of relatively large amounts of data with relatively low latency tolerance. Other types of device, for example used for autonomous vehicle communications and for other critical applications, may be characterised by data that should be transmitted through the network with low latency and high reliability. A single device type might also be associated with different traffic profiles / characteristics depending on the application(s) it is running. For example, different consideration may apply for efficiently supporting data exchange with a smartphone when it is running a video streaming application (high downlink data) as compared to when it is running an Internet browsing application (sporadic uplink and downlink data) or being used for voice communications by an emergency responder in an emergency scenario (data subject to stringent reliability and latency requirements).

[0009] In view of this there is expected to be a desire for current wireless communications networks, for example those which may be referred to as 5G or new radio (NR) systems / new radio access technology (RAT) systems, or indeed future 6G wireless communications, as well as future iterations / releases of existing systems, efficiently to support connectivity for a wide range of devices associated with different applications and different characteristic data traffic profiles and requirements.

[0010] One example of a new service is referred to as Ultra Reliable Low Latency Communications (URLLC) services which, as its name suggests, requires that a data unit or packet be communicated with a high reliability and with a low communications delay. An example application is extended Reality (XR), which may be provided by various user equipment such as wearable devices. XR combines real-world and virtual environments, incorporating aspects such as augmented reality (AR), mixed reality (MR), and virtual reality (VR), and thus requires high quality and minimised interaction delay. Services such as URLLC with applications such as XR therefore represent a challenging example for communications systems. Such services may require a communications device to transmit and to receive data of different types (such as video, audio, control data etc.) which can have different quality of service requirements for transmission and reception via a radio access network (RAN) and a core network (CN) of the wireless communications system.

[0011] 5G / NR and 6G require continuous evolution to support these new applications and scenarios, which can present new challenges for efficiently handling communications in wireless communications systems that need to be addressed.

[0012] 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.

[0013] SUMMARY OF THE DISCLOSURE

[0014] The present disclosure can help address or mitigate at least some of the issues discussed above.

[0015] According one aspect, a communications device can operate to transmit and to receive via a wireless communications network, by establishing a multi-modal bearer to carry first data in first packets for transmission via a wireless access interface provided by a source base station of the radio access network, RAN, and a core network, CN, of the wireless communications network, and to carry second data in second packets for transmission via the wireless access interface provided by the source base station of the RAN and the CN of the wireless communications network, the multi-modal bearer being configured to transmit the first packets according to a first quality-of-service, QoS, and the second packets according to a second QoS, which is different from the first QoS. The multimodal bearer is for transmitting and receiving the first and the second packets. The communications device further operates to transmit the first packets and the second packets to the source base station of the RAN and via the CN of the wireless communications network via the multi-modal bearer. The communications device then performs a handover by receiving a handover command to handover from the source base station of the RAN to a target base station of the RAN. The communications device then reconfigures the multi-modal bearer for transmitting the first packets with the first QoS and the second packets with the second QoS to the target base station of the RAN and via the CN, and transmits the first packets and the second packets using the re-configured multi-modal bearer via the target base station. Reconfiguration can include establishing dedicated radio access bearers with QoS flows, which are the same as those, which were provided by the source infrastructure equipment. In other examples, reconfiguration can include arranging a different configuration of one or more dedicated radio access bearers and adapting the QoS flows in correspondence with a different configuration and radio dedicated bearers. The transmitting of the first packets and of the second packets via the target base station includes adapting each packet to include a time stamp or other indication which can allow a receiver to determine an order of the first and the second packets with respect to each other.

[0016] According to example embodiments, the communications device adapts the packets of different data flows of the multi-modal bearer to include a time stamp or other indication from which a relative order of transmission of the packets or reproduction of packets can be determined so that there is or can be determined a synchronisation or relative order of the packets in each of the different QoS flows. As such during handover different QoS flows can be synchronised because these are more likely to be disrupted by the process of the handover.

[0017] According to another aspect, an infrastructure equipment of a radio access network of a wireless communications network acting as a target base station receives a handover request from an infrastructure equipment acting as a source base station to handover a communications device to the infrastructure equipment as a target. The handover request includes a request for a multi-modal bearer to support a packet data unit (PDU) session with at least one radio bearer supporting the multimodal bearer comprising a plurality of quality of service (QoS) flows for the communications device, if a successful handover is completed. The infrastructure equipment, acting as a target for the handover, determines whether it can accept the handover of the communications device with the multi-modal bearer. According to the determination, the infrastructure equipment either responds to the handover request with a handover reject message, or responds to the handover request with an accept message, and as part of the handover if accepted, communicates an identifier, ID, of the multimodal bearer to a core network of the wireless communications network.

[0018] According to example embodiments, an infrastructure equipment communicates a multi-modal ID to the core network when acting as a target for handover. When acting as a target for handover the infrastructure equipment is configured to communicate the multi-modal ID of a multi-modal bearer, which the infrastructure equipment should support in order to be a handover target to the core network. As such, as part of the reconfiguration of the bearer supporting the multi-modal communication, a path switch is performed in the core network. As part of that path switch process, the multi-modal bearer can be either reconfigured by the target infrastructure equipment or adapted in accordance with the capability of the target infrastructure equipment to support different QoS flows required by the multi-modal bearer.

[0019] Respective aspects and features of the present disclosure are defined in the appended claims and include a communications device (for example, a UE), an infrastructure equipment of the wireless indications network 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 (NR) 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 is a schematic block diagram illustrating functional components which operate to support communication of data to and from a communications device (UE) which may require one or more radio bearers to communicate data with different data flows having a different quality of service QoS;

[0026] Figure 4 is a schematic block diagram corresponding to that shown in Figure 3 illustrating vision of a multi modal bearer from the communications device between the communications device and a user plane function within the core network which is controlled by an application function with which example embodiments find application; Figure 5 is a schematic representation of a 5G / NR wireless access network corresponding to that shown in Figure 1 but adapted to illustrate scenario in which a communications device roams from one cell to another cell requiring handover of a multi modal bearer from a source base station to a target base station;

[0027] Figure 6 is a schematic representation illustrating a handover of a multi modal bearer from a source base station to a target base station, which is adapted in accordance with embodiments of the present disclosure;

[0028] Figure 7 is a message flow diagram illustrating messages exchanged by components of the wireless medication system in order to establish an multi modal bearer with the target base station following handover according to example embodiments; and

[0029] Figure 8 is a part message sequence and part flow diagram illustrating operations performed by communications device to handover from a source infrastructure equipment to a target infrastructure equipment in which the communications device is communicating using a multimodal bearer; and

[0030] Figure 9 is a part message sequence and part flow diagram illustrating operations performed by an infrastructure equipment acting as a target for a communications device communicating using a multimodal bearer.

[0031] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Wireless Communications Network Including Radio Access Technology (5G)

[0033] 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) 110 are connected to distributed control units (DUs) 142 by a connection interface represented as a line 116. Each of the TRPs 110 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 provided by each TRP 110 as represented by a circle 112, each DU 142, with its TRPs 110, forms a cell of the wireless communications network with a unique cell-ID. In some examples each TRP 110 can form a cell with its own cell-ID. As such, wireless communications devices 114 which are within a radio communications range provided by the cells 112 can transmit and receive signals to and from the TRPs 10 via the wireless access interface. Each of the distributed units 142 are connected to a central unit (CU) 140 (which may be referred to as a controlling node) via an interface 146. The central unit 140 is then connected to the core network 120 which may contain all other functions required to transmit data for communicating to and from the wireless communications devices and the core network 120 may be connected to other networks

[0034] As will be appreciated by those acquainted with the wireless communications network according to a 5G standard as shown in Figure 1, the CU 140, DU 142 and TRPs 110 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. More generally, the gNB (TRP, CU, DU) performs the functions of a base station using terminology which is consistent with previous generations of wireless communications networks. A communications device 114 is represented in Figure 1 within the coverage area of the first communication cell 112. This communications device 114 may thus exchange signalling with the first CU 140 in the first communication cell 112 via one of the distributed units / TRPs 110 associated with the first communication cell 112. The communications devices 114 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.

[0035] It will further be appreciated that Figure 1 represents merely one example of a proposed architecture for a RAT communications system in which approaches in accordance with the principles described herein may be adopted, and the functionality disclosed herein may also be applied in respect of wireless communications systems having different architectures.

[0036] 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 110, which corresponds to TRP 110 in Figure 1, comprises, as a simplified representation, a transmitter circuitry 212, a receiver circuitry 214 and a controller circuitry or controlling processor 216 which may operate to control the transmitter circuitry 212 and the receiver circuitry 214 to transmit and receive radio signals to one or more UEs within a cell 112 (not shown in Figure 2 for clarity) provided by the TRP 110. As shown in Figure 2, the TRP 110 is connected to a DU 142 via a physical interface 116, which may be a fibre optic cable, for example. The physical interface 116 therefore provides a communications link for data and signalling traffic from the TRP 110 via the DU 142 and a CU 140 to a core network 120 An interface 146 between the DU 142 and the CU 140 is known as the Fl interface which can be a physical or a logical interface. The Fl interface 146 between the DU 142 and the CU 140 may operate in accordance with specifications 3GPP TS 38.470 [TS38.470] and 3GPP TS 38.473 [TS38.473], and may be formed from a fibre optic or other wired or wireless high bandwidth connection. The connection between the gNB 242 and the core network 260 can be generally referred to as a backhaul and comprises for the control plane an N2 interface (or NGAP interface) as specified in TS 38.413 and for the user plane an N3 interface between the CU 140 and the UPF in the CN, using GTP-U protocol as specified in TS 29.281. Within the gNB 242 the physical interface between the DU 142 and CU 140 is the Fl interface 146.

[0037] As shown in Figure 2, the TRP 110 may be configured to transmit downlink radio signals and receive uplink radio signals from a UE 114 via a direct wireless communications link 200 which may be a Uu interface in one example. The UE 114 is shown to include a transmitter circuitry 222, a receiver circuitry 224 and a controller circuitry 226 which is configured to control the transmitter circuitry 222 and the receiver circuitry 224 to transmit uplink signals to the TRP 110 and to receive downlink signals from the TRP 110 over the wireless communications link 200 formed between the UE 114 and the TRP 110.

[0038] The transmitter circuitry 212, 222 and the receiver circuitry 214, 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, circuitry and devices in order to transmit and receive radio signals in accordance for example with the 5G / NR standard. The controller circuitry 216, 226, 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).

[0039] As mentioned above, the TRP 110, DU 142 and the CU 140 may collectively form the gNB 242, which is an example of infrastructure equipment of a radio access network of a wireless communications network, which, as mentioned above, may be generally referred to as a base station. Therefore, references to the UE 114 communicating with the TRP 110 can alternatively be considered as references to the UE 114 communicating with the gNB 242. Furthermore, it will be appreciated that the UE 114 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.

[0040] Multi-Modal Traffic

[0041] Embodiments of the present technique concern a transmission of data from a UE having different QoS requirements via the radio access network (RAN) and the core network (CN) to an Application Function (AF) for example. Data services requiring different QoS requirements can be referred to as multi-modal services, which consist of several data flows (named as multi-modal flows) that are related to each other and may come from different sources. Each data flow (single-modal data) may be seen as one type of data (for example audio, video, positioning, haptic data) associated with the same communication service. Data flows that comprise a multi-modal service may come from a single UE, either via a single device or via multiple devices connected to the single UE that can access the 5GS, or from multiple UEs.

[0042] 3GPP Technical Specification TS 23.501 V18.3.0 (2023-09) [TS23.501] discloses techniques for both roaming and non-roaming scenarios and includes interworking between 5G System (5GS) and an Evolved Packet System (EPS), mobility within 5GS, QoS, policy control and charging, authentication and in general 5G System wide features e.g. SMS, Location Services, Emergency Services. Of particular relevance to the present disclosure, [TS23.501] in section 5.3712 discloses policy control enhancements to support multi-modal services. As explained in [TS23.501], multi-modal services are supported providing for different quality of service (QoS) transport by different data types to support applications or different applications from the same UE. For the single UE case, an expected multimodal application behaviour is that those data flows that are closely related and require strong application coordination for correct delivery of the multi-modal application data are transmitted in a single PDU session. This is so that a QoS can be provided for the single PDU which will satisfy all of the multi-modal application data.

[0043] Figure 3 provides a simplified representation of 5GS network components from both a radio network side and a core network side, which interfaces with an Application Function (AF). The interconnection and operation of these components is disclosed in [TS23.501], To assist with the explanation of the example embodiments, a brief summary of the components shown in Figure 3 is provided as follows:

[0044] The UE 114 and gNB 242 correspond to those shown in Figures 1, 2 and 3 as explained above with a supporting explanation, which will not be repeated here. Application Function (AF) controls transmission of multi-modal data to one or more applications by influencing traffic routing Enforcement Control information determined by a PCF (see below) when requested by the AF or statically preconfigured in the PCF. The AF may influence the UPF (see below) selection and traffic routing via PCF and / or a Network Exposure Function (NEF).

[0045] Access Mobility Function (AMF) is a control plane function in the 5G core network that handles connection management including registration management, reachability management, mobility management and various functions relating to security and access management and authorisation.

[0046] Policy Control Function (PCF) supports a unified policy framework that governs network behaviour and provides policy rules to control plane functions, which are enforced by those functions.

[0047] Session Management Function (SMF) forms Packet Data Unit (PDU) session management, which allows the UE to access 5G services via PDU sessions of a PDU session type or Ethernet PDU session type and controls PDU sessions, which are accessed by a UE.

[0048] User Plane Function (UPF) performs several functions relating to a UE’s allocation of PDU sessions and Internet Protocol functionality including packet routing and forwarding packet inspection, user plane policy enforcement and QoS handling for user plane data.

[0049] In accordance with a 3GPP convention, references points between the function shown in Figure 3 are as follows:

[0050] Uu: Interface between the UE and the gNB.

[0051] N1 : Reference point between the UE and the AMF.

[0052] N2: Reference point between the (R)AN and the AMF.

[0053] N3: Reference point between the (R)AN and the UPF.

[0054] N4: Reference point between the SMF and the UPF.

[0055] N5: Reference point between the PCF and an AF or TSN AF.

[0056] N7: Reference point between the SMF and the PCF.

[0057] Nil: Reference point between the AMF and the SMF.

[0058] More information is disclosed in [TS23.501], According TS 23.501, section 5.37.2 the following services are provided for policy control enhancements to support multi-modal services:

[0059] - The Nnef_AFsessionWithQoS service allows the AF to provide, at the same time, service requirements, for each media that comprise the multi-modal service, a Multi-modal Service ID and QoS monitoring requirements for multiple IP data flows associated to a multi-modal service.

[0060] - The AF may provide to the PCF a Multi-modal Service ID, as an explicit indication that the application traffics are related to a multi-modal service. The PCF may use this information to derive the correct Policy and Charging Control (PCC) rules and apply QoS policies for data flows that are part of a specific multi-modal application.

[0061] - The AF may provide QoS monitoring requirement for data flows associated to a multimodal service to the PCF (either directly or via NEF) with in a certain period. The PCF generates the authorized QoS Monitoring policy for these service data flows. NOTE: In order to start the monitoring of the packet delay results for data flows associated to a multi-modal service within a certain period, the PCF needs to receive the data from AF accordingly.

[0062] - The multi-modal services are carried in a single PDU session for one UE.

[0063] In addition to the features that are provided for the case that the flows are associated with a single UE, the following features are provided for the case where the flows are associated with more than one UE:

[0064] - The same DNN / S-NSSAI combination for the multi-modal service should be selected among the multiple UEs. The URSP Rule evaluation framework is used to ensure that the same DNN / S-NSSAI is selected.

[0065] - The AF may allocate the same Multi-modal Service ID to all UE PDU sessions that compose a multi-modal service. The PCF may take this information into account (e.g. to allocate a specific QoS profile) when processing each PDU session independently. The data flows that contribute to the service experience, but may still be valid stand-alone, may be transmitted over separate PDU sessions to and / or from multiple UEs on both the uplink and the downlink.

[0066] If multiple PCFs are involved, the PCF(s) can take policy decisions according to the input provided by the AF. There is no support for policy coordination among the multiple PCF(s). Policy decisions are taken by each PCF separately on a per PDU session basis

[0067] In summary, the 5G core network architecture shown in Figure 3 provides functions to support multimodal services to UEs running applications providing user services. One or more applications can require communication of data with different QoS requirements. Figure 4 provides an illustrative representation of transmission of multi-modal data via a 5GS using the functions shown in Figure 3. As shown in Figure 4, a PDU session 400 is provided to a UE 114 by the wireless communications network. The PDU session 400 transports IP packets to and from the UE 114 from and to the UPF 402. According to this example, the one or more applications active on the UE 114 generate packet data (e.g. IP packets) for transmission by the radio access network, RAN, and the 5G core network to and from a destination. The data being transmitted or received has different requirements according to its application (video, voice, data, time sensitive data etc.) which accordingly requires transmission and reception according to different QoS requirements. As shown for the example in Figure 4, the PDU session 400 comprises a first Data Radio Bearer (DRB1) 410 and a second Data Radio Bearer (DRB2) 412. Data which may be in the form of PDUs are transmitted via the first and second DRBs 410, 412 according to different QoS requirements as illustrated by respective IP tunnels for 420, 422. The transmission of packets via the IP tunnels 420, 422 is supported by the first and second DRBs 410, 412 via the radio access network, RAN, and via first and second GTP-U tunnels, which is an IPbased transmission and reception via the DU, the CU and the core network to the UPF. Data of different types with different QoS requirements is transmitted and received by different IP flows 430 for 432 via the core network under the control of Application Function, AF.

[0068] Whilst Figure 4 provides an example, it will be understood that data with different QoS requirements may be mapped onto a single DRB or each different QoS requirement may be transmitted onto a separate DRB. That is, data with different QoS requirements may be transmitted or received via a single DRB, which may be regarded as a multi-modal bearer. If data is transmitted by the same DRB, then constraints may be applied to the data being transmitted even though the QoS requirements vary or are different between different data types in order that this data with different QoS requirements are transmitted via the same DRB. For the example of Figure 4, there are two QoS flows 420, 422 mapped to separate DRBs 410, 412. To assist co-ordination by network functions, an indication can be provided that different DRBs carry different QoS flows for different data types. The different QoS flows may be common to the same application. Accordingly, in some examples, a common session identifier (ID) or multi-modal ID should be made available to the RAN. It has also been proposed that a UE can provide information about coordination and synchronisation between IP flows.

[0069] Focussing on an intra UE scenario (different QoS flows from the same UE), there may be more than one QoS flow carrying traffic with either the same or different QoS requirements. These QoS flows could be mapped to the same or different DRBs in RAN. A current rule in RAN is that QoS flows with same / similar QoS characteristics can be mapped to the same DRB. In order to ensure coordination between traffic being carried over these QoS flows / Data Radio Bearers (DRB), the RAN should be aware of a multi-modal session ID.

[0070] For downlink communications, a gNB should be able to perform scheduling such that synchronisation and QoS coordination between DRBs associated with different IP flows is achieved, because this information is known by the network elements concerned. For uplink communications, changes are required so that different logical channels carrying traffic related to different QoS flows are correctly multiplexed when scheduled using MAC Transport Blocks (TB). There is a further problem that during handover, as a result of a UEs mobility, some gNBs may not be able to support multi-modal flows or may have resource limitations, such that they may not be able to allocate different DRBs for different QoS flows. The present technique concerns the mobility of the UE as it performs a handover from a source gNB to a target gNB. Such an example scenario is illustrated with respect to the diagram of a 5G wireless communications system shown in Figure 1 adapted to illustrate a scenario in which handover is required as shown in Figure 5.

[0071] In Figure 5, a UE 114 roams from a source cell illustrated with dotted circle 112S to a target cell illustrated with dotted circle 112T. The source cell 112S and the target cell 112T in this example are formed by TRP’s 110S, HOT which connect to the core network respectively via the DU and a CU and respective interfaces 110S, 116S, 142S, 146S, 140S, 161, HOT, 116T, 142T, 146T, 140T, 162 which have been explained above with reference to Figure 1. As will be appreciated according to this example, the UE 114 is providing a service through an application which communicates multi-media data controlled by the application function, AF, as explained above. Therefore, example embodiments are concerned with supporting handover between gNBs, or more generally base stations, where one source / target base station supports multi-modal flows or does not and another source / target base station does or does not support multi-modal flow and so there needs to be a change in the configuration and mapping between IP flows and DRBs.

[0072] According to example embodiments a UE (communications device) can operate to transmit and to receive via a wireless communications network, by establishing a multimodal bearer having different QoS flows for packets carrying different data. When performing a handover by receiving a handover command to handover from a source base station of the RAN to a target base station of the RAN, the UE re-configures the multi-modal bearer for the target base station of the RAN. Reconfiguration can include establishing dedicated radio access bearers with QoS flows, which are the same as those or different to those, which were provided by the source base station. The UE adapts each packet to include a time stamp or other indication which can allow a receiver to determine an order of packets with respect to each other, so that a relative order of transmission of the packets or reproduction of packets can be determined to synchronise a relative order of the packets in each different QoS flow of the multimodal bearer. As such, during handover, different QoS flows can be synchronised because these are more likely to be disrupted by the process of the handover. According to another aspect an infrastructure equipment communicates a multi-modal ID to the core network when acting as a target for handover and communicates the multi-modal ID of a multi-modal bearer, which the infrastructure equipment should support in order to be a handover target to the core network. As such, as part of the reconfiguration of the bearer supporting the multi-modal communication, a path switch is performed in the core network. As part of that path switch process, the multi-modal bearer can be either reconfigured by the target infrastructure equipment or adapted in accordance with the capability of the target infrastructure equipment to support different QoS flows required by the multi-modal bearer.

[0073] Both Source and Target gNB Support Multi-modal Flow

[0074] In one example, both a source cell 112S, 11 OS and a target 112T, HOT support a multi-modal flow and the target cell 112T, 110T is able to allocate the same configuration as the source cell 112S, 1 IOS. For this example, a technical problem resides in preparing the target cell 112T, HOT for the multimodal bearers or bearer and ensuring that synchronisation can be maintained between respective IP flows with different QoS within the same or different DRBs.

[0075] Figure 6 provides an example illustration corresponding to the scenario presented in Figure 4 in the case where a UE 114 handovers multi-modal data flow formed by a PDU session 600 from a source gNB 242S to a target gNB 242T as a PDU session 602. Corresponding to the example illustrated in Figure 4, each of the two data flows with different QoS 620, 622 carried by DRBs 632, 634 are handed-over from the source gNB 242S to the target gNB 242T as nominally indicated as a new PDU session 602 with corresponding QoS flows 650, 652 carried by DRBs 662, 664. According to this example, the source gNB 242S (base station) in this case should receive multi-modal identifier (ID) from the AMF during a PDU session setup procedure. It is assumed in this example scenario that there are two different IP flows 420, 422which are mapped to two different DRBs 632, 634 over the Uu interface, as shown in Figures 4 and 6. The gNB 242S (source base station) will then perform downlink scheduling of these two DRBs 632, 634, such that they are scheduled during the same scheduling period in order to maintain synchronisation and QoS coordination of the respect QoS flows 620, 622. For uplink communication, the UE 114 is configured with logical channel priority (same priority for both DRBs 632, 634 in RRC configuration, such that both DRBs 632, 634 are multiplexed to the same MAC Transport Block and QoS and synchronisation requirements are met. As will be appreciated corresponding DRBs 662, 664 and the QoS Flows 650, 652 need to be configured at the target gNB 242T (target base station).

[0076] According to example embodiments, in order to maintain synchronisation between the QoS flows by each of the DRBs 632, 634, once a UE 114 has been instructed to handover from the source gNB’s 242 S to the target gNB 242T, the UE 114 may adapt the packets transmitted on the uplink by each of the QoS flows 650, 652. The packets are adapted to include in each packet 670 playtime information, in terms of a timestamp at which this packet should be played out, included in the user plane packets (either at upper layers or radio layer header). This information about playtime is then available and used at RAN. Alternatively, the field added to the packet header indicates a relative order when the packets should be arranged so that a relative synchronisation between different types of data carried by different QoS flows can be maintained between transmitter and receiver.

[0077] For the downlink transmission, the source gNB 242S forwards the packets to the target gNB 242T with a timestamp or other playtime information from which an order of the user plane packets can be determined for transmission by the target gNB 242T to the UE 114. As for the uplink transmission, the order information can be added to the packet header to provide information indicative of relative order of the packets for each of the different QoS flows. According to example embodiments as shown in Figure 6. each of the packets 670 transmitted by the QoS flows 650, 652, is adapted by the UE 114 so that the header includes information representing a playtime or timestamp which can be used by the gNB 242T or the receiving application to resynchronise respective QoS flows in order to provide the service supported by the new session 602. Therefore, each packet 670 comprising a header 672 and payload 674 includes an adapted header 672, which includes a field 676 indicating a play time information, in terms of a timestamp at which this packet should be played out. This information is therefore included in the user plane packets belonging to different DRBs for multi-modality or indeed the same DRB for multi-modality. This information is inserted in PDCP header 672. Alternatively, this information may be included in RLC or MAC layer header.

[0078] Similarly for packets forwarded by the source gNB 242S to the target gNB 242T, the header of each packet 690 comprising a header 692 and payload 694 includes an adapted header 692, which includes a field 696 indicating a play time information, in terms of a timestamp at which this packet should be played out. This information is therefore included in the user plane packets for multi-modality in different QoS flows, which are forwarded to the target gNB 242T for transmission on the downlink to the UE114 by the source gNB 242 S.

[0079] According to example embodiments, the source gNB, 242S (source base station) may then provide a multi-modal ID and associated configuration to the target gNB 242T (target base station) during handover preparation. This can be done by the source gNB 242 S by providing its configuration of the PDU session 600 to the target gNB 242T as part of an adapted Handover Request message over the Xn interface, such as described in TS38.300 and TS38.423.

[0080] If the target gNB 242T supports multi-modal PDU sessions, then it will continue with the same configuration as with the PDU session established by the source cell 112S with each IP flow 650, 652 mapped to a separate DRB 662, 664. The source cell 112S will then provide its own configuration to the target cell 112T. During handover procedure, if there is a change in the multi-modal bearer and how this is configured then the UE as part of an RRC reconfiguration adapts to a new configuration of DRB’s according to the multi-modal bearer. If there is no configuration change then UE 114 will continue with the same configuration as the source cell 112S.

[0081] According to example embodiments, the target cell 112T may report the multi-modal ID to the core network. This may also be reported in a Path Switch Response message. By doing so, the AMF and other parts of the core network are aware of an application termination point in the RAN. It will also help in selecting the correct UPF because not all UPFs in the network may support multi-modal sessions.

[0082] Source gNB Supports Multi-Modal But Target gNB Can Only Support a Single DRB

[0083] A target gNB 242T (target base station) can change a configuration depending on its radio conditions and operator or network vendor policies if it cannot support a multi-modal PDU session. In one example, the target cell 242T does not configure two DRBs but a single DRB for both IP flows. In this case, the target gNB 242T may be configured to perform any of the following options:

[0084] 1. The target gNB 242T rejects the handover of the UE 114 from the source gNB 112S, by sending a handover preparation failure message. The source gNB 112S then tries to find another cell to which the UE 114 can be handed over.

[0085] 2. The target gNB 242T accepts the handover and then informs the AF via the core network functions (Path Switch signalling) that the target gNB 242T cannot perform QoS differentiation. That is to say, the target gNB cannot operate with a new PDU session 602 having more than one DRB or more than one QoS flow. The AF may adjust the frame rate or similar requirements so that QoS coordination is not required, which results in all of the plurality of IP flows having the same QoS requirements.

[0086] 3. The AF then provides sufficient information to the 5GC and eventually to the RAN (PDU Session Modification procedure) so that the RAN is able to perform differentiation even for the same DRB. That is to say that a single DRB is configured to carry different QoS flows. Alternatively, the UE 114 can provide information to the target gNB 242T, which is required at target gNB 242T to provide IP flow QoS information and how to distinguish packets of different QoS within the same flow. QoS coordination refers to an arrangement in which different QoS parameters are configured for different IP flows for a PDU session.

[0087] QoS differentiation refers to an arrangement in which all QoS flows are mapped to a DRB, which only supports either the same QoS parameters or characteristics or different QoS characteristics depending on the information received from an Application and RAN either via CN or UE.

[0088] According to example embodiments therefore, as part of an operation of the target cell 112T when rejecting a request for handover of the UE 114, the source gNB 242S may provide sufficient information for the target gNB 242T with the effect that it does not retry the same gNB. In one option, a new handover cause value is provided as part of a handover reject message for example which may indicate that QoS differentiation is not supported. That is to say that it is not possible for a gNB as a handover target to support different QoS parameters between IP flows forming part of the same PDU session.

[0089] According to some example embodiments, as well as the target gNB reporting the multi-modal ID to the core network in a path switch response message as part of a handover procedure of a multi-modal PDU session, the path switch response message may also include QoS differentiation information that is an indication of QoS parameters between IP flows forming part of the same PDU session which carries the different QoS flows. That is to say that the target gNB 242T reports the multi-modal ID and QoS flow differentiation information to the core network in the Path Switch Response message. The AMF then initiates a PDU session update procedure based on a new mapping when the target gNB does not support the same configuration.

[0090] Example embodiments are illustrated by the message sequence diagram shown in Figure 7, where like parts and corresponding features, shown in any of Figures 1 to 6 have the same references. The message sequence diagram of Figure 7 is adapted from a conventional procedure which is part of a PDU session establishment by the UE 114 with the source gNB or RAN 242S and a subsequent handover from the source RAN 242 S to the target RAN 242T. Accordingly, only those parts relevant to the present disclosure will be described in detail. More information can be found in TS23.501. As shown in Figure 7 as part of a PDU session establishment, a PDU session set up message 700 is sent by the UE 114 to the AMF. The AMF then exchanges messages with the SMF via the UPF, which includes retrieving policy rules and other parameters which are required for the PDU session. The SM Policy Association 702 exchanged between the SMF and the PCF can include an indication that the PDU session established for the UE is multi-modal and includes a multi-modal ID. The SMF communicates the multi-modal ID to the AMF 706, which is then sent by the AMF to the source RAN 242S.

[0091] As shown in Figure 7 box 710 represents a conventional communication of user data using the created PDU session to support a service provided to the UE from the core network. However, the UE 114 is then controlled by the 5 G RAN to perform a handover from the source RAN 242 S to the target RAN 242T. A handover request 730 is sent by the source RAN 242S, which includes a multi-modal ID. The handover request message 730 is sent to the target RAN 242T, which includes the multi-modal ID. An acknowledgement is then sent by the target RAN 242T to the source RAN 242S. The source RAN 242S then sends an RRC reconfiguration message 740 to the UE 114, which responds with a RRC reconfiguration complete message 742 to the target RAN 242T. The target RAN 242T then sends a path switch request message 744, which includes the multi-modal ID to the AMF. The AMF sends a path switch message 746 to the UPF and corresponding operations are performed as for the PDU session establishment. Again the SM policy association 750 exchanged between the SMF and the PCF includes the multi-modal ID. Accordingly, the core network and the RAN can be configured to support a multi-modal operation during handover by adapting the QoS flows or supporting different QoS flows according to a capabilities of the target RAN 242T.

[0092] According to example embodiments, the target gNB 242T transmits to UE a Radio Resource Control (RRC) reconfiguration message as part of the handover to reconfigure the UE to transmit and receive the first packets and the second packets using the multimodal bearer via the gNB 242T.

[0093] Source gNB Supports a Single DRB but the Target Supports QoS Differentiation

[0094] For this example, the source gNB, which is configured with a single DRB as part of a PDU session and the target gNB, has a cabability to support QoS differentiation so that it can be configured with a PDU session having two or more DRBs. That is the UE also has a capability to support multiple QoS flows and this UE capability is transferred during handover to the target cell, so that the target cell is informed that multi-modality can be supported. The target gNB provides its own configuration to the UE via source gNB and include QoS differentiation in a Path Switch Request. The AMF allocates a multi-modal ID in a path switch request acknowledge message and the AMF also initiates a PDU session modification procedure.

[0095] According to example embodiments, the target gNB can provide a QoS differentiation configuration to the AMF in a Path Switch Request message. The AMF provides a multi-modal ID to the target gNB in a Path Switch Request acknowledge message, if source gNB did not provide this to the target gNB and eventually the target gNB did not provide the multi-modal ID in a Path Switch Request message but included QoS differentiation information.

[0096] According to other example embodiments, the target gNB does not change a DRB configuration during handover, but rather keeps the configuration used at the source gNB. The target gNB informs the AMF in a path switch request message that it can support multimodal flow coordination. The AMF then initiates a PDU session modification procedure and of part and that as part of this procedure, a second RRC reconfiguration message is sent to the UE informing the UE of a DRB reconfiguration. Accordingly, this two-step approach adapts the PDU session so that this can be supported by the target gNB.

[0097] As will be appreciated and according to example embodiments the re-configuring the multi-modal bearer for transmitting and receiving the first packets with the first QoS and the second packets with the second QoS to or from the target gNB 242T of the RAN and via the CN comprises re-configuring the multimodal bearer in accordance with a capability of the gNB 242T.

[0098] According to example embodiments the gNB 242 S as a source base station for handover sends a handover request to the target gNB 242T to handover a UE 114 from the source gNB 242S to the target gNB 242T. The handover request includes a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one DRB supporting the communication of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed. The source gNB 242S then receives an accept message in response to the handover request from the target gNB 242T and sends first packets and second packets to the target gNB 242T for transmission to the UE 114 via a reconfigured multi-modal bearer, for example, those of the first packets and the second packets which would have been transmitted by the source gNB 242S to the UE 114. In order to preserve a relative order of the first packets and the second packets, the source gNB 242S adapts the first packets and the second packets to include an indication of a temporal order of the first packets and the second packets. In some examples, after receiving the accept message from the target gNB 242T, the source gNB 242S determines that first packets and second packets, which would have been transmitted by the source gNB need to be sent by the target gNB after the handover completion via the reconfigured multi-modal bearer, and adapts the determined first and second packets to include the indication of the temporal order of the first packets and the second packets.

[0099] Summary of Operations

[0100] A summary of operations of a wireless communication system according to example embodiments is illustrated by flow diagrams provided in Figures 8 and 9. Figures 8 and 9 respectively illustrate operations of a UE and a target gNB.

[0101] In Figure 8 a UE 114 receives an RRC configuration message 801 from a source gNB 242S and performs an operation to establish a multi-modal bearer PDU session 802 in order to support an application requiring different types of data with different QoS requirements. After establishing a multi-modal bearer PDU session, the UE 114 sends an RRC configuration complete message 804. The UE 114 then transmits and receives data for example as first packets and second packets respectively via respective DRBs having first and second QoS flows with different QoS parameters as part of a PDU session 806, as represented by respectively arrows 810, 812. In accordance with a conventional handover process, the source gNB 242S transmits an RRC Reconfiguration message, which effectively forms a handover command 814 to the UE 114. The source gNB 242s then transmits an RRC reconfiguration message 816 to the UE 114 and in response to the UE 114 establishes 822 a multi-modal bearer PDU session via the target gNB 242T.

[0102] As explained above, in some examples the target gNB 242T may only support a multi-modal bearer without some adaptation of the multiple QoS workflows. As such, the RRC reconfiguration message 820 can provide an indication of the bearer or bearers, which the UE 114 should establish whether this is a multi-DRB or a single DRB with adapted QoS flows. After establishing the multi-modal bearer PDU session via the target gNB 242T, the UE 114 can transmit an RRC complete message 824.

[0103] According to example embodiments, if it is determined that the UE 114 should handover to the target gNB 240T, and once the multiple QoS flows have been established for the multi-modal bearer, then at step 830 the UE adapts the packets of the different QoS flows. The packets are adapted by introducing a timestamp into the header or other field value providing an indication of a relative order of transmission of the packets or a relative order of reproduction. This is so, that an application using different types of data can synchronise the different QoS flows in order to provide the service of the application being processed on the UE 114. Accordingly, the packets, which have been adapted at the operation 830 are transmitted and received as represented by arrows 832, 834 transmitting and receiving data packets via different QoS flows as represented by an operation 836.

[0104] Operations performed by a target gNB 242T in order to establish a multi-modal bearer or indeed to reject a handover in correspondence with the operation shown in Figure 8 are shown in Figure 9. As shown in Figure 9, as a first operation 900, a target gNB 242T receives a handover request message 902 from a source gNB 242S. According to example embodiments, the handover request message 902 includes a multi-modal ID, which both identifies a multi-modal bearer and indicates that the target gNB 242T is required to support this multi-modal bearer. As such, if the target gNB 242T were to accept the handover then it would need to establish a multi-modal bearer and inform the core network, CN, of this multi-modal bearer. This is so that if the target gNB 242T cannot support a multi-modal bearer which has the same configuration of the multi-modal bearer supported by the source gNB 242S, but can support a bearer with adapted QoS flows, then the CN can require the UE to adopt a change in the QoS flows and to reconfigure an adapted bearer. The CN can accordingly establish an adapted bearer through the target gNB 242T for supporting data communications with the UE 114 adapted in respect of a capability of the target gNB be 242T. The CN can perform appropriate action to review and to reconfigure the bearer supported by the target gNB 242T and the UE 114.

[0105] At operation 904, the target gNB 242T determines whether it can accept the handover of the UE 114 or reject the request. Accordingly, a handover response message 906 is sent from the target gNB 242T to the source gNB 242S indicating whether the handover is accepted or rejected. As explained above, if the handover response message 906 is to reject the handover, then the source gNB 242S may receive with the handover response message 906 an indication as to why the target gNB 242T cannot accept the handover. For example, this may be because the target gNB 242T cannot support a multimodal bearer. As a result, the source gNB 242 will no longer send handover requests for UEs requiring multi-modal bearers to the gNB 242T, thereby reducing communications and improving efficiency.

[0106] If the target gNB 242T can accept the handover request then the gNB 242T sends a path switch request message with the multi-modal ID to the core network functions responsible for managing a change in a path of the multi-modal bearer via the RAN and the CN. In the example shown in Figure 9, the path switch request message 908 is sent to the AMF with the multi-modal ID. The AMF, which is responsible for mobility management, may then send a path switch request message 912 to the AF with the mode multi-modal ID. In response, the AF sends a path switch request acknowledgement 914 to the AMF and the AMF sends a path switch request 916 acknowledgement to the gNB 242T. The target gNB 242T then establishes 918 a multi-modal bearer PDU session for the UE 114 as part of the handover and subsequently the target gNB 242T transmits and receives first and second packets 920 for first and second QoS flows 920 in this example as explained above.

[0107] In one example the handover request message 900 and multi-modal ID as well as other information relevant to the handover is communicated from the source gNB 242S to the target gNB 242T via an interface between the source 242S and the target 242T for example via an Xn interface.

[0108] In some examples, whilst the target gNB 242T can accept the handover, it cannot support the multimodal bearer in the form as this was provided between the UE and the source gNB 242S. If the target gNB 242T cannot support a multi-modal bearer PDU session in the form in which it has been provided to the UE 114 by the source gNB 242S, then as part of the path switch request 908 to the AMF and the AF 912, the AF with the AMF may instruct the target gNB 242T and the UE 114 to reconfigure one or more DRBs. The one or more DRB’s are configured and the UE and the AF establishes one or more adapted QoS flows in order that the UE 114 can continue a communication session via the target gNB 242T.

[0109] Example of Applications Requiring Different QoS Requirements

[0110] For completeness some explanation of applications requiring the communication of multi-modal data are provided to assist in understanding example embodiments. Systems incorporating advanced wireless communications technology are expected to support different services (or types of services), which may be characterised by different QoS parameters for latency, data rate and / or reliability. For example, Enhanced Mobile Broadband (eMBB) services are characterised by high capacity with a requirement to support up to 20 Gb / s. A requirement for Ultra Reliable and Low Latency Communications (URLLC) services is that one transmission of a 32 byte packet is required to be transmitted from the radio protocol layer 2 / 3 SDU ingress point. Radio protocol layer 2 / 3 SDU egress point of the radio interface within 1 ms with a reliability of 1 - 10'5(99.999 %) or higher (99.9999 %). Enhanced URLLC (eURLLC) specifies features that require high reliability and low latency, such as factory automation, transport industry, electrical power distribution, etc. It should be appreciated that the Uplink Control Information (UCI) for URLLC and eMBB will have different requirements. extended Reality (XR) and Cloud Gaming refer to various types of augmented, virtual, and mixed environments, where human-to-machine and human-to-human communications are performed with the assistance of handheld and wearable end user devices (UEs). XR and Cloud Gaming are two more recently developed applications, that are considered important for NR Rel-18 and beyond (also known as 5G Advanced).

[0111] XR traffic is rich in video, especially in the downlink, with a typical frame rate of 60 Hz, which leads to a data transmission with non-integer periodicity in NR, i.e. the periodicity is not an integer number of subframes and in this example, the periodicity is 16.67 ms. Due to varying frame encoding delay and network transfer time, the packet arrival at the gNB may experience random jitter. The non-integer and jitter characteristics of XR traffic is known as quasi-periodic traffic. In addition to jitter, the packet size also varies within a range; that is the packet size in each period is random.

[0112] The above are all examples of different applications and services in which communications multi-modal data may be required, that is data of different types having different QoS requirements with parameters such as delay, latency, jitter, bandwidth etc.

[0113] It will be appreciated that the above description for clarity has described embodiments with reference to different functional units, circuitry and / or processors. However, it will be apparent that any suitable distribution of functionality between different functional units, circuitry and / or processors may be used without detracting from the embodiments.

[0114] Described embodiments may be implemented in any suitable form including hardware, software, firmware or any combination of these. Described embodiments may optionally be implemented at least partly as computer software running on one or more data processors and / or digital signal processors. The elements and components of any embodiment may be physically, functionally and logically implemented in any suitable way. Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the disclosed embodiments may be implemented in a single unit or may be physically and functionally distributed between different units, circuitry and / or processors.

[0115] 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.

[0116] The following numbered paragraphs provide further example aspects and features of the present technique:

[0117] Paragraph 1. A method of operating a communications device to transmit and to receive via a wireless communications network, the method comprising establishing a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting communication of a plurality of different quality of service, QoS, flows for the communications device comprising at least a first QoS for transmitting and receiving first packets which is different from a second QoS for transmitting and receiving second packets, transmitting the first packets and the second packets to the source base station of the RAN and via the CN of the wireless communications network via the multi-modal bearer, receiving a handover command to handover from the source base station of the RAN to a target base station of the RAN, re-configuring the multi-modal bearer for transmitting and receiving the first packets with the first QoS and the second packets with the second QoS to the target base station of the RAN and via the CN, and transmitting the first packets and the second packets using the re-configured multi-modal bearer via the target base station, wherein the transmitting the first packets and the second packets via the target base station includes adapting each packet to include an indication of a temporal order of the first and the second packets.

[0118] Paragraph 2. A method of paragraph 1, wherein the adapting each of the first packets and the second packets to include an indication of a temporal order of the first and the second packets comprises adding a field to a header of each of the first packets and the second packets indicating a relative time with respect to others of the first packets and the second packets.

[0119] Paragraph 3. A method of paragraph 2, wherein the field indicates a time at which data carried in a payload of the packet should be reproduced by an application.

[0120] Paragraph 4. A method of paragraph 1 or 2, wherein the first packets and the second packets are packets according to a Packet Data Convergence Protocol, PDCP.

[0121] Paragraph 5. A method of paragraph 1 or 2, wherein the first packets and the second packets are packets according to a Radio Link Control, RLC, layer protocol.

[0122] Paragraph 6. A method of paragraph 1 or 2, wherein the first packets and the second packets are packets according to a Medium Access Control, MAC, layer protocol.

[0123] Paragraph 7. A method of any of paragraphs 1 to 6, wherein the multi-modal bearer comprises either a single Dedicated Radio Bearer, DRB, to carry the first packets and the second packets or establishing a first DRB to carry the first packets and a second DRB to carry the second packets as a multi-modal bearer.

[0124] Paragraph 8. A method of any of paragraphs 1 to 7, wherein the establishing a multi-modal bearer comprises establishing the multi-modal bearer to carry first data in the first packets for transmission and reception via a wireless access interface provided by the source base station of the radio access network, RAN, and a core network, CN, of the wireless communications network, and to carry second data in the second packets for transmission and reception via the wireless access interface provided by the source base station of the RAN and the CN of the wireless communications network, the multimodal bearer being configured to transmit the first packets according to the first quality-of-service, QoS, and the second packets according to the second QoS, which is different from the first QoS.

[0125] Paragraph 9. A method of any of paragraphs 1 to 8, wherein the re-configuring the multi-modal bearer for transmitting and receiving the first packets with the first QoS and the second packets with the second QoS to the target base station of the RAN and via the CN comprises re-configuring the multimodal bearer in accordance with a capability of the infrastructure equipment acting as the handover target. Paragraph 10. A method of any of paragraphs 1 to 9, comprising receiving the first packets and the second packets using the re-configured multi-modal bearer from the target base station following the handover, determining a temporal order of the first and the second packets received from the target base station using the re-configured multi-modal bearer from an indication of an indication of the temporal order of the first packets and the second packets included in each of the first packets and the second packets, and processing the first packets and the second packets in accordance with the determined order.

[0126] Paragraph 11. A method of operating an infrastructure equipment of a radio access network of a wireless communications network as a handover target base station, the method comprising receiving a handover request from an infrastructure equipment of the radio access network as a source base station to handover a communications device to the infrastructure equipment as a target base station, with a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting the transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, determining whether the infrastructure equipment can accept the handover as a target infrastructure equipment with the multi-modal bearer, and according to the determination, either responding to the handover request with a handover reject message, or responding to the handover request with an accept message, and as part of the handover if accepted, communicating an identifier, ID, of the multi-modal bearer to a core network of the wireless communications network.

[0127] Paragraph 12. A method of paragraph 11, wherein the handover request received from the source infrastructure equipment includes the multi-modal bearer ID.

[0128] Paragraph 13. A method of paragraph 11 or 12, wherein the communicating the multi-modal bearer ID to the core network includes communicating the multi-modal bearer ID to an Access Mobility Function, AMF, of the core network.

[0129] Paragraph 14. A method of any of paragraphs 11, 12 or 13, wherein the multi-modal bearer ID is communicated as part of a Path Switch Request message.

[0130] Paragraph 15. A method of any of paragraphs 11 to 14, wherein the responding to the handover request with an accept message comprises communicating the accept message to an Application Function, AF, of the core network, with an indication that the infrastructure equipment as the handover target can support the multi-modal bearer with a plurality of QoS flows with different QoS parameters for a PDU session.

[0131] Paragraph 16. A method of paragraph 15, comprising configuring the infrastructure equipment as handover target with a plurality of radio bearers to support the PDU session, each radio bearer carrying a quality of service, QoS, flow having different QoS parameters.

[0132] Paragraph 17. A method of paragraph 11, wherein the responding to the handover request with a handover reject message comprises communicating a handover reject message to the source infrastructure equipment with an indication that the infrastructure equipment as handover target does not support a plurality of QoS flows with different QoS parameters for a PDU session.

[0133] Paragraph 18. A method of paragraphs 11 or 12, wherein the responding to the handover request with an accept message comprises communicating the accept message to an Application Function, AF, of the core network, with an indication that the infrastructure equipment as the handover target cannot support the multi-modal bearer with different QoS flows, the target infrastructure equipment being configured with a radio bearer to support the PDU session adapted for the target infrastructure equipment.

[0134] Paragraph 19. A method of paragraph 18, comprising receiving at the infrastructure equipment as a handover target a new mapping of packets for different QoS flows to one or more radio bearers from Access Mobility Function, AMF, of the core network as part of a PDU session update procedure to re-configure the target infrastructure equipment with one or more radio bearers to support the PDU session adapted for the target infrastructure equipment.

[0135] Paragraph 20. A method of paragraph 11, wherein the responding to the handover request with an accept message comprises communicating the accept message to an Access Mobility Function, AMF, of the core network with an indication that the infrastructure equipment as the handover target is required to support the multi-modal bearer with different QoS flows, receiving from the AMF a multi-modal ID of the multi-modal bearer to be provided to the communications device via the infrastructure equipment as handover target, if the source infrastructure equipment did not provide to the target the multi-modal bearer ID.

[0136] Paragraph 21. A method of paragraph 20, wherein the accept message with the indication that the infrastructure equipment as the handover target is required to support the multi-modal bearer with different QoS flows is communicated as part of a Path Switch Request message.

[0137] Paragraph 22. A method of paragraph 20 or 21, comprising receiving at the infrastructure equipment as a handover target a mapping of packets for different QoS flows to one or more radio bearers from the AMF as part of a PDU session modification procedure.

[0138] Paragraph 23. A method of paragraph 22, comprising transmitting to the communications device a Radio Resource Control, RRC, reconfiguration message as part of the handover to reconfigure the communications device to transmit and receive the first packets and the second packets using the multimodal bearer via the infrastructure equipment as the target base station.

[0139] Paragraph 24. A method of any of paragraphs 11 to 23, comprising reconfiguring the infrastructure equipment as handover target with a plurality of radio bearers to support the PDU session, each radio bearer carrying a quality of service, QoS, flow having different QoS parameters, the plurality of radio bearers being the same as that which is configured for the infrastructure equipment as the handover source base station, communicating to an Access Mobility Function, AMF, of the core network an indication that the infrastructure equipment as the handover target can support the multi-modal bearer with different QoS flows corresponding to that configured for the handover source base station, receiving from the AMF a multi-modal bearer modification indication, as part of a PDU session modification procedure, and transmitting to the communications device a RRC reconfiguration message, informing the communications device of a radio bearer reconfiguration.

[0140] Paragraph 25. A method of operating an infrastructure equipment of a radio access network of a wireless communications network as a source base station for handover, the method comprising sending a handover request to an infrastructure equipment of the radio access network as a target base station to handover a communications device from the infrastructure equipment acting as the source base station to the infrastructure equipment as the target base station, the handover request including a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, receiving an accept message in response to the handover request from the infrastructure equipment acting as the target base station, sending first packets and second packets to the target base station for transmission to the communications device via a reconfigured multi-modal bearer, wherein the first packets and the second packets are adapted to include an indication of a temporal order of the first packets and the second packets.

[0141] Paragraph 26. A method of paragraph 25, wherein the sending the first packets and the second packets to the target base station comprises receiving the accept message from the target infrastructure equipment, determining that first packets and second packets, which would have been transmitted by the infrastructure equipment acting as a source base station, need to be sent by the infrastructure equipment acting as the target base station after the handover completion via the reconfigured multimodal bearer, and adapting the determined first and second packets to include the indication of the temporal order of the first packets and the second packets.

[0142] Paragraph 27. A method of paragraph 25 or 26, wherein the handover request sent to the target infrastructure equipment includes the multi-modal bearer ID.

[0143] Paragraph 28. A communications device for transmitting and receiving via a wireless communications network, the communications device comprising transmitter circuitry configured to transmit signals in one or more cells of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals in one or more cells via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to establish a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting communication of a plurality of different quality of service, QoS, flows for the communications device comprising at least a first QoS for transmitting and receiving first packets which is different from a second QoS for transmitting and receiving second packets, to transmit the first packets and the second packets to the source base station of the RAN and via the CN of the wireless communications network via the multi-modal bearer, to receive a handover command to handover from the source base station of the RAN to a target base station of the RAN, to re-configure the multi-modal bearer for transmitting and receiving the first packets with the first QoS and the second packets with the second QoS to the target base station of the RAN and via the CN, and to transmit the first packets and the second packets using the re-configured multi-modal bearer via the target base station, and to adapt each packet to include an indication of a temporal order of the first and the second packets.

[0144] Paragraph 29. An infrastructure equipment of a radio access network of a wireless communications network as a handover target base station, the infrastructure equipment comprising transmitter circuitry configured to transmit signals to one or more of the communications devices of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals from one or more of the communications devices via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals representing data, the control circuitry being configured in combination with the receiver circuitry and the transmitter circuitry to receive a handover request from an infrastructure equipment of the radio access network as a source base station to handover a communications device to the infrastructure equipment as a target base station, with a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting the transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, to determine whether the infrastructure equipment can accept the handover as a target infrastructure equipment with the multi-modal bearer, and according to the determination, either to respond to the handover request with a handover reject message, or to respond to the handover request with an accept message, and to communicate an identifier, ID, of the multi-modal bearer to a core network of the wireless communications network, as part of the handover if accepted.

[0145] Paragraph 30. An infrastructure equipment of a radio access network of a wireless communications network as a source base station for handover, the infrastructure equipment comprising transmitter circuitry configured to transmit signals to one or more of the communications devices of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals from one or more of the communications devices via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals representing data, the control circuitry being configured in combination with the receiver circuitry and the transmitter circuitry to send a handover request to an infrastructure equipment of the radio access network as a target base station to handover a communications device from the infrastructure equipment acting as the source base station to the infrastructure equipment as the target base station, the handover request including a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, to receive an accept message in response to the handover request from the infrastructure equipment acting as the target base station, to send first packets and second packets to the target base station for transmission to the communications device via a reconfigured multi-modal bearer, wherein the first packets and the second packets are adapted to include an indication of a temporal order of the first packets and the second packets.

[0146] Paragraph 31. Circuitry for transmitting and receiving via a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals in one or more cells of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals in one or more cells via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to establish a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting communication of a plurality of different quality of service, QoS, flows for the communications device comprising at least a first QoS for transmitting and receiving first packets which is different from a second QoS for transmitting and receiving second packets, to transmit the first packets and the second packets to the source base station of the RAN and via the CN of the wireless communications network via the multi-modal bearer, to receive a handover command to handover from the source base station of the RAN to a target base station of the RAN, to re-configure the multi-modal bearer for transmitting and receiving the first packets with the first QoS and the second packets with the second QoS to the target base station of the RAN and via the CN, and to transmit the first packets and the second packets using the re-configured multi-modal bearer via the target base station, and to adapt each packet to include an indication of a temporal order of the first and the second packets.

[0147] Paragraph 32. Circuitry of a radio access network of a wireless communications network as a handover target base station, the circuitry comprising transmitter circuitry configured to transmit signals to one or more of the communications devices of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals from one or more of the communications devices via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals representing data, the control circuitry being configured in combination with the receiver circuitry and the transmitter circuitry to receive a handover request from an infrastructure equipment of the radio access network as a source base station to handover a communications device to the infrastructure equipment as a target base station, with a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting the transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, to determine whether the infrastructure equipment can accept the handover as a target infrastructure equipment with the multi-modal bearer, and according to the determination, either to respond to the handover request with a handover reject message, or to respond to the handover request with an accept message, and to communicate an identifier, ID, of the multi-modal bearer to a core network of the wireless communications network, as part of the handover if accepted.

[0148] Paragraph 33. Circuitry of a radio access network of a wireless communications network as a source base station for handover, the circuitry comprising transmitter circuitry configured to transmit signals to one or more of the communications devices of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals from one or more of the communications devices via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals representing data, the control circuitry being configured in combination with the receiver circuitry and the transmitter circuitry to send a handover request to an infrastructure equipment of the radio access network as a target base station to handover a communications device from the infrastructure equipment acting as the source base station to the infrastructure equipment as the target base station, the handover request including a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, to receive an accept message in response to the handover request from the infrastructure equipment acting as the target base station, to send first packets and second packets to the target base station for transmission to the communications device via a reconfigured multi-modal bearer, wherein the first packets and the second packets are adapted to include an indication of a temporal order of the first packets and the second packets. REFERENCES

[0149] [TS23.501] TS 23.501 V18.3.0 (2023-09)

[0150] [TS38.470] 3GPP TS 38.470

[0151] [TS38.473] 3GPP TS 38.473

Claims

CLAIMS1. A method of operating a communications device to transmit and to receive via a wireless communications network, the method comprising establishing a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting communication of a plurality of different quality of service, QoS, flows for the communications device comprising at least a first QoS for transmitting and receiving first packets which is different from a second QoS for transmitting and receiving second packets, transmitting the first packets and the second packets to the source base station of the RAN and via the CN of the wireless communications network via the multi-modal bearer, receiving a handover command to handover from the source base station of the RAN to a target base station of the RAN, re-configuring the multi-modal bearer for transmitting and receiving the first packets with the first QoS and the second packets with the second QoS to the target base station of the RAN and via the CN, and transmitting the first packets and the second packets using the re-configured multi-modal bearer via the target base station, wherein the transmitting the first packets and the second packets via the target base station includes adapting each packet to include an indication of a temporal order of the first and the second packets.

2. A method of claim 1, wherein the adapting each of the first packets and the second packets to include an indication of a temporal order of the first and the second packets comprises adding a field to a header of each of the first packets and the second packets indicating a relative time with respect to others of the first packets and the second packets.

3. A method of claim 2, wherein the field indicates a time at which data carried in a payload of the packet should be reproduced by an application.

4. A method of claim 1, wherein the first packets and the second packets are packets according to a Packet Data Convergence Protocol, PDCP.

5. A method of claim 1, wherein the first packets and the second packets are packets according to a Radio Link Control, RLC, layer protocol.

6. A method of claim 1, wherein the first packets and the second packets are packets according to a Medium Access Control, MAC, layer protocol.

7. A method of claim 1, wherein the multi-modal bearer comprises either a single Dedicated Radio Bearer, DRB, to carry the first packets and the second packets or establishing a first DRB to carry the first packets and a second DRB to carry the second packets as a multi-modal bearer.

8. A method of claim 1, wherein the establishing a multi-modal bearer comprises establishing the multi-modal bearer to carry first data in the first packets for transmission and reception via a wireless access interface provided by the source base station of the radio access network, RAN, and a core network, CN, of the wireless communications network, and to carry second data in the second packets for transmission and reception via the wireless access interface provided by the source base station of the RAN and the CN of the wireless communications network, the multi-modal bearer being configured to transmit the first packets according to the first quality-of-service, QoS, and the second packets according to the second QoS, which is different from the first QoS.

9. A method of claim 1, wherein the re-configuring the multi-modal bearer for transmitting and receiving the first packets with the first QoS and the second packets with the second QoS to the target base station of the RAN and via the CN comprises re-configuring the multimodal bearer in accordance with a capability of the infrastructure equipment acting as the handover target.

10. A method of claim 1, comprising receiving the first packets and the second packets using the re-configured multi-modal bearer from the target base station following the handover, determining a temporal order of the first and the second packets received from the target base station using the re-configured multi-modal bearer from an indication of an indication of the temporal order of the first packets and the second packets included in each of the first packets and the second packets, and processing the first packets and the second packets in accordance with the determined order.

11. A method of operating an infrastructure equipment of a radio access network of a wireless communications network as a handover target base station, the method comprising receiving a handover request from an infrastructure equipment of the radio access network as a source base station to handover a communications device to the infrastructure equipment as a target base station, with a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting the transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, determining whether the infrastructure equipment can accept the handover as a target infrastructure equipment with the multi-modal bearer, and according to the determination, either responding to the handover request with a handover reject message, or responding to the handover request with an accept message, and as part of the handover if accepted, communicating an identifier, ID, of the multi-modal bearer to a core network of the wireless communications network.

12. A method of claim 11, wherein the handover request received from the source infrastructure equipment includes the multi-modal bearer ID.

13. A method of claim 11, wherein the communicating the multi-modal bearer ID to the core network includes communicating the multi-modal bearer ID to an Access Mobility Function, AMF, of the core network.

14. A method of any of claims 11, wherein the multi-modal bearer ID is communicated as part of a Path Switch Request message.

15. A method of claim 11, wherein the responding to the handover request with an accept message comprises communicating the accept message to an Application Function, AF, of the core network, with an indication that the infrastructure equipment as the handover target can support the multi-modal bearer with a plurality of QoS flows with different QoS parameters for a PDU session.

16. A method of claim 15, comprising configuring the infrastructure equipment as handover target with a plurality of radio bearers to support the PDU session, each radio bearer carrying a quality of service, QoS, flow having different QoS parameters.

17. A method of claim 11, wherein the responding to the handover request with a handover reject message comprises communicating a handover reject message to the source infrastructure equipment with an indication that the infrastructure equipment as handover target does not support a plurality of QoS flows with different QoS parameters for a PDU session.

18. A method of claims 11, wherein the responding to the handover request with an accept message comprises communicating the accept message to an Application Function, AF, of the core network, with an indication that the infrastructure equipment as the handover target cannot support the multi-modal bearer with different QoS flows, the target infrastructure equipment being configured with a radio bearer to support the PDU session adapted for the target infrastructure equipment.

19. A method of claim 18, comprising receiving at the infrastructure equipment as a handover target a new mapping of packets for different QoS flows to one or more radio bearers from Access Mobility Function, AMF, of the core network as part of a PDU session update procedure to re-configure the target infrastructure equipment with one or more radio bearers to support the PDU session adapted for the target infrastructure equipment.

20. A method of claim 11, wherein the responding to the handover request with an accept message comprises communicating the accept message to an Access Mobility Function, AMF, of the core network with an indication that the infrastructure equipment as the handover target is required to support the multi-modal bearer with different QoS flows, receiving from the AMF a multi-modal ID of the multi-modal bearer to be provided to the communications device via the infrastructure equipment as handover target, if the source infrastructure equipment did not provide to the target the multi-modal bearer ID.

21. A method of claim 20, wherein the accept message with the indication that the infrastructure equipment as the handover target is required to support the multi-modal bearer with different QoS flows is communicated as part of a Path Switch Request message.

22. A method of claim 20, comprising receiving at the infrastructure equipment as a handover target a mapping of packets for different QoS flows to one or more radio bearers from the AMF as part of a PDU session modification procedure.

23. A method of claim 22, comprising transmitting to the communications device a Radio Resource Control, RRC, reconfiguration message as part of the handover to reconfigure the communications device to transmit and receive the first packets and the second packets using the multimodal bearer via the infrastructure equipment as the target base station.

24. A method of claim 11, comprising reconfiguring the infrastructure equipment as handover target with a plurality of radio bearers to support the PDU session, each radio bearer carrying a quality of service, QoS, flow having different QoS parameters, the plurality of radio bearers being the same as that which is configured for the infrastructure equipment as the handover source base station, communicating to an Access Mobility Function, AMF, of the core network an indication that the infrastructure equipment as the handover target can support the multi-modal bearer with different QoS flows corresponding to that configured for the handover source base station, receiving from the AMF a multi-modal bearer modification indication, as part of a PDU session modification procedure, and transmitting to the communications device a RRC reconfiguration message, informing the communications device of a radio bearer reconfiguration.

25. A method of operating an infrastructure equipment of a radio access network of a wireless communications network as a source base station for handover, the method comprisingsending a handover request to an infrastructure equipment of the radio access network as a target base station to handover a communications device from the infrastructure equipment acting as the source base station to the infrastructure equipment as the target base station, the handover request including a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, receiving an accept message in response to the handover request from the infrastructure equipment acting as the target base station, sending first packets and second packets to the target base station for transmission to the communications device via a reconfigured multi-modal bearer, wherein the first packets and the second packets are adapted to include an indication of a temporal order of the first packets and the second packets.

26. A method of claim 25, wherein the sending the first packets and the second packets to the target base station comprises receiving the accept message from the target infrastructure equipment, determining that first packets and second packets, which would have been transmitted by the infrastructure equipment acting as a source base station, need to be sent by the infrastructure equipment acting as the target base station after the handover completion via the reconfigured multimodal bearer, and adapting the determined first and second packets to include the indication of the temporal order of the first packets and the second packets.

27. A method of claim 25, wherein the handover request sent to the target infrastructure equipment includes the multi-modal bearer ID.

28. A communications device for transmitting and receiving via a wireless communications network, the communications device comprising transmitter circuitry configured to transmit signals in one or more cells of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals in one or more cells via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to establish a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting communication of a plurality of different quality of service, QoS, flows for the communications device comprising at least a first QoS for transmitting and receiving first packets which is different from a second QoS for transmitting and receiving second packets, to transmit the first packets and the second packets to the source base station of the RAN and via the CN of the wireless communications network via the multi-modal bearer,to receive a handover command to handover from the source base station of the RAN to a target base station of the RAN, to re-configure the multi-modal bearer for transmitting and receiving the first packets with the first QoS and the second packets with the second QoS to the target base station of the RAN and via the CN, and to transmit the first packets and the second packets using the re-configured multi-modal bearer via the target base station, and to adapt each packet to include an indication of a temporal order of the first and the second packets.

29. An infrastructure equipment of a radio access network of a wireless communications network as a handover target base station, the infrastructure equipment comprising transmitter circuitry configured to transmit signals to one or more of the communications devices of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals from one or more of the communications devices via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals representing data, the control circuitry being configured in combination with the receiver circuitry and the transmitter circuitry to receive a handover request from an infrastructure equipment of the radio access network as a source base station to handover a communications device to the infrastructure equipment as a target base station, with a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting the transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, to determine whether the infrastructure equipment can accept the handover as a target infrastructure equipment with the multi-modal bearer, and according to the determination, either to respond to the handover request with a handover reject message, or to respond to the handover request with an accept message, and to communicate an identifier, ID, of the multi-modal bearer to a core network of the wireless communications network, as part of the handover if accepted.

30. An infrastructure equipment of a radio access network of a wireless communications network as a source base station for handover, the infrastructure equipment comprising transmitter circuitry configured to transmit signals to one or more of the communications devices of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals from one or more of the communications devices via the wireless access interface, andcontroller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals representing data, the control circuitry being configured in combination with the receiver circuitry and the transmitter circuitry to send a handover request to an infrastructure equipment of the radio access network as a target base station to handover a communications device from the infrastructure equipment acting as the source base station to the infrastructure equipment as the target base station, the handover request including a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, to receive an accept message in response to the handover request from the infrastructure equipment acting as the target base station, to send first packets and second packets to the target base station for transmission to the communications device via a reconfigured multi-modal bearer, wherein the first packets and the second packets are adapted to include an indication of a temporal order of the first packets and the second packets.

31. Circuitry for transmitting and receiving via a wireless communications network, the circuitry comprising transmitter circuitry configured to transmit signals in one or more cells of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals in one or more cells via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to establish a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting communication of a plurality of different quality of service, QoS, flows for the communications device comprising at least a first QoS for transmitting and receiving first packets which is different from a second QoS for transmitting and receiving second packets, to transmit the first packets and the second packets to the source base station of the RAN and via the CN of the wireless communications network via the multi-modal bearer, to receive a handover command to handover from the source base station of the RAN to a target base station of the RAN, to re-configure the multi-modal bearer for transmitting and receiving the first packets with the first QoS and the second packets with the second QoS to the target base station of the RAN and via the CN, and to transmit the first packets and the second packets using the re-configured multi-modal bearer via the target base station, and to adapt each packet to include an indication of a temporal order of the first and the second packets.

32. Circuitry of a radio access network of a wireless communications network as a handover target base station, the circuitry comprising transmitter circuitry configured to transmit signals to one or more of the communications devices of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals from one or more of the communications devices via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals representing data, the control circuitry being configured in combination with the receiver circuitry and the transmitter circuitry to receive a handover request from an infrastructure equipment of the radio access network as a source base station to handover a communications device to the infrastructure equipment as a target base station, with a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting the transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, to determine whether the infrastructure equipment can accept the handover as a target infrastructure equipment with the multi-modal bearer, and according to the determination, either to respond to the handover request with a handover reject message, or to respond to the handover request with an accept message, and to communicate an identifier, ID, of the multi-modal bearer to a core network of the wireless communications network, as part of the handover if accepted.

33. Circuitry of a radio access network of a wireless communications network as a source base station for handover, the circuitry comprising transmitter circuitry configured to transmit signals to one or more of the communications devices of the wireless communications network via a wireless access interface, receiver circuitry configured to receive signals from one or more of the communications devices via the wireless access interface, and controller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals representing data, the control circuitry being configured in combination with the receiver circuitry and the transmitter circuitry to send a handover request to an infrastructure equipment of the radio access network as a target base station to handover a communications device from the infrastructure equipment acting as the source base station to the infrastructure equipment as the target base station, the handover request including a request for a multi-modal bearer to support a packet data unit, PDU, session with at least one radio bearer supporting transmission and reception of a plurality of quality of service, QoS, flows for the communications device if a successful handover is completed, to receive an accept message in response to the handover request from the infrastructure equipment acting as the target base station, to send first packets and second packets to the target base station for transmission to the communications device via a reconfigured multi-modal bearer, wherein the first packets and thesecond packets are adapted to include an indication of a temporal order of the first packets and the second packets.

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