Methods, communication devices and infrastructure equipment

Abstract

Communication devices, infrastructure equipment and methods of operating such devices for efficient handling of mobility procedures in such wireless communications networks. The infrastructure equipment can transmit, to a communication device, a layer 1 / layer 2 triggered mobility (LTM) candidate configuration via RRC signalling, the configuration indicating one or more conditions for the communication device to perform LTM, request LTM or report measurement results to the infrastructure equipment. Subsequently, the communication device can perform LTM based on the conditions being fulfilled or based on receiving an instruction to perform LTM.

Description

[0001] This application claims priority under the Paris Convention to European patent application EP 24166066.1, filed on 25 March 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to communication apparatus and infrastructure equipment for wireless communication networks, and methods for operating such communication apparatus and infrastructure equipment for more efficient handling of mobility procedures in such wireless communication networks. Background Technology

[0003] The “Background Art” description provided herein is intended to provide a general overview of the context of this disclosure. To the extent described in the Background Art section herein, the work of the currently named inventor, and other aspects of the description that do not constitute prior art at the time of application, are neither explicitly nor implicitly acknowledged as prior art to this application.

[0004] Previous generations of mobile telecommunications systems (such as those based on the UMTS and LTE architectures defined by 3GPP) were able to support a wider range of services than the simple voice and messaging services offered by earlier generations. For example, thanks to the improved radio interface and enhanced data rates provided by LTE systems, users can enjoy high-data-rate applications such as mobile video streaming and mobile video conferencing, which were previously only available through fixed-line data connections. Therefore, there is a strong demand for deploying such networks, and the coverage areas of these networks (i.e., the geographical locations where the network is accessible) are expected to continue to grow rapidly.

[0005] Current and future wireless communication networks are expected to routinely and efficiently support communication with an increasingly wide range of devices, associated with a broader range of data traffic distributions and types optimized for by existing systems. For example, future wireless communication networks are expected to efficiently support communication with devices including reduced-complexity devices, machine-type communication (MTC) devices, high-resolution video displays, virtual reality headsets, extended reality (XR), and more. Some of these different types of devices may be deployed on a large scale, such as low-complexity devices supporting the “Internet of Things” (IoT), and may generally be associated with transmitting relatively small amounts of data and having relatively high latency tolerance. Other types of devices (e.g., supporting high-definition video streaming) may be associated with transmitting relatively large amounts of data and having relatively low latency tolerance. Other types of devices (e.g., for autonomous vehicle communication and other critical applications) may have data characteristics that should be transmitted over low-latency and high-reliability networks. A single device type may also be associated with different traffic distributions / characteristics depending on the application it is operating in. For example, when smartphones are used for internet browsing applications (sporadic uplink and downlink data) or for voice communication by emergency responders in emergency scenarios (data subject to strict reliability and latency requirements), different considerations can be applied to efficiently support data exchange with smartphones when smartphones are running video streaming applications (high downlink data).

[0006] In light of this, current wireless communication networks—such as those that may be called 5G or New Radio (NR) systems / New Radio Access Technology (RAT) systems, or indeed future 6G wireless communication, as well as future iterations / versions of existing systems—are expected to efficiently support connectivity for a wide range of devices associated with different applications and data traffic distributions and requirements. This desire to support these new use cases and scenarios brings new challenges to efficiently handling communications within wireless communication systems, challenges that need to be addressed. Summary of the Invention

[0007] This disclosure can help resolve or mitigate at least some of the problems discussed above.

[0008] The relevant aspects and features of this disclosure are defined in the appended claims.

[0009] According to a first aspect, a method of operating a communication device is provided, the communication device being configured to transmit signals to and / or receive signals from an infrastructure device of a wireless communication network via a radio access interface, the method comprising: receiving low-layer triggered mobility (LTM) candidate configuration information from a source infrastructure device providing a source cell, wherein the LTM candidate configuration information includes at least indications of one or more conditions for the communication device to migrate to a target cell provided by a target infrastructure device, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; performing the measurements indicated in the LTM candidate configuration information; and initiating an LTM procedure for migration to the target cell based on the measurements and the one or more conditions.

[0010] According to a second aspect, a method for a communication device is provided, the method comprising: receiving low-layer triggered mobility (LTM) candidate configuration information from a source infrastructure device, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; performing the measurements indicated in the LTM candidate configuration information; sending the indications of these measurements to the source infrastructure device and / or requesting to perform an LTM procedure for migration to a target cell provided by a target infrastructure device; receiving an LTM command from the source infrastructure device, the LTM command including instructions for initiating an LTM procedure for migration to the target cell; and initiating an LTM procedure for migration to the target cell.

[0011] According to a third aspect, a method is provided for an infrastructure device configured to transmit signals to and / or receive signals from one or more communication devices in a wireless communication network via a radio interface provided by the wireless communication network, the method comprising: transmitting low-layer triggered mobility (LTM) candidate configuration information to the communication devices, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication devices as indicated in the LTM candidate configuration information, wherein: the LTM candidate configuration information indicates one or more conditions for the communication devices to initiate an LTM procedure for migration to a target cell provided by the target infrastructure device, or the LTM candidate configuration information indicates one or more conditions for the communication devices to transmit indications of these measurements to the infrastructure device and / or to perform a request for an LTM procedure for migration to the target cell.

[0012] It should be understood that the above general description and the following detailed description are exemplary and not intended to limit the technology. The described embodiments, along with further advantages, will be best understood in conjunction with the accompanying drawings and the following detailed description. Attached Figure Description

[0013] A more complete understanding of this disclosure and its many accompanying advantages will be readily obtained when the accompanying drawings are taken in conjunction with the following detailed description, in which the same reference numerals denote the same or corresponding parts in various views, and wherein: Figure 1 These illustrations schematically depict aspects of an LTE-type wireless telecommunications system that can be configured to operate according to certain embodiments of this disclosure. Figure 2 These illustrations schematically depict aspects of an NR-type wireless telecommunications system that can be configured to operate according to certain embodiments of this disclosure. Figure 3 It is a schematic block diagram of example infrastructure equipment and communication apparatus that can be configured to operate according to certain embodiments of this disclosure; Figure 4A It represents the gNB distributed unit (DU) and gNB control unit (CU) that communicate via the F1 interface; Figure 4B They are respectively by Figure 4A The diagram shows a schematic representation of the protocol stack used for communication control plane data in the gNB DU and gNB CU operations. Figure 4C They are respectively by Figure 4A The diagram shows a schematic representation of the protocol stack used for communicating user plane data during gNB DU and gNB CU operations. Figure 5 This schematically illustrates the functional division of the gNB among CU-CP, CU-UP, and DU based on the current architecture; Figure 6 This shows the range of Layer 1 / Layer 1 Triggered Mobility (LTM) in the current 3GPP specification; Figure 7 This is copied from [9] and shows an example message sequence for LTM according to the current 3GPP specification; Figure 8 The process of LTM conditions being indicated to a conditional LTM by a communication device is illustrated.

[0014] Figure 9 The process of a conditional LTM (Low-Temperature Measurement) is illustrated, in which a communication device reports measurement results to infrastructure equipment.

[0015] Figure 10 This illustrates the process of a conditional LTM where a communication device sends an LTM request to infrastructure equipment.

[0016] Figure 11 This is a flowchart illustrating a method for a communication device according to an example of this disclosure.

[0017] Figure 12 This is a flowchart illustrating a method for a communication device according to an example of this disclosure.

[0018] Figure 13 This is a flowchart illustrating a method for infrastructure equipment according to an example of this disclosure. Detailed Implementation

[0019] 4G (Long Term Evolution) Advanced Radio Access Technology

[0020] Figure 1 A schematic diagram is provided illustrating some basic functions of a mobile telecommunications network / system 6 that generally operates according to LTE principles but may also support other radio access technologies and can be adapted to implement embodiments of this disclosure. Figure 1 Certain aspects of the various components and their corresponding operating modes are well known and defined in relevant standards managed by the 3GPP (RTM) organization, and described in many relevant books, such as Holma H. ​​and Toskala A[1]. It should be understood that operational aspects of the telecommunications network discussed herein that are not specifically described (e.g., related to specific communication protocols and physical channels used for communication between different components) can be implemented according to any known technology, such as according to relevant standards and known proposed modifications and additions to relevant standards.

[0021] Network 6 includes multiple base stations 1 connected to core network 2 (which may be, for example, an evolved packet core (EPC)). Each base station provides a coverage area 3 (i.e., a cell) within which data can be transmitted to and received from communication device 4. Although Figure 1 Each base station 1 is shown as a single entity, but those skilled in the art will understand that some functions of a base station can be performed by different, interconnected components, such as antennas, remote wireless heads, amplifiers, etc. Overall, one or more base stations can form a radio access network.

[0022] Data is transmitted from base station 1 to communication device 4 within its corresponding coverage area 3 via radio downlink (DL). Data is transmitted from communication device 4 to base station 1 via radio uplink (UL). Core network 2 routes data to and from communication device 4 via the corresponding base station 1 and provides functions such as authentication, mobility management, and billing. Terminal devices may also be referred to as mobile stations, user equipment (UE), user terminals, mobile radios, communication devices, etc. Services provided by core network 2 may include connectivity to the Internet or external telephone services. Core network 2 may further track the location of communication device 4 so that it can effectively contact (i.e., page) communication device 4 to transmit downlink data to communication device 4.

[0023] A base station is an example of network infrastructure equipment and may also be referred to as a transceiver station, Node B, e-Node B, eNB, g-Node B, gNB, etc. In this regard, different terms are often associated with different generations of wireless telecommunications systems for elements providing substantially similar functionality. However, some embodiments of this disclosure can also be implemented in different generations of wireless telecommunications systems, and for simplicity, certain terms may be used without considering the underlying network architecture. That is, the use of specific terms with respect to certain example implementations is not intended to indicate that these implementations are limited to the specific generation of networks most commonly associated with that specific term.

[0024] New radio access technology (5G)

[0025] Figure 2 An example configuration of a wireless communication network using some of the terminology proposed and used for NR and 5G is shown. Figure 2 In this configuration, multiple Transmit and Receive Points (TRPs) 10 are connected to multiple Distributed Control Units (DUs) 41, 42 via a connection interface indicated by line 16. Each TRP 10 is arranged to transmit and receive signals via a wireless access interface within the available radio frequency bandwidth of the wireless communication network. Thus, within the range of radio communication via the wireless access interface, each TRP 10 forms a cell of the wireless communication network, as indicated by circle 12. In this way, wireless communication devices 14 within the radio communication range provided by cell 12 can transmit signals to and receive signals from TRPs 10 via the wireless access interface. Each distributed unit 41, 42 is connected to a central unit (CU) 40 (which may be referred to as a control node) via interface 46. The central unit 40 is then connected to a core network 20 (which may be referred to as, for example, 5GC), which may contain all other functions required to transmit and receive data from wireless communication devices, and which may be connected to other networks 30.

[0026] Figure 2 The elements of the wireless access network shown can be related to... Figure 1 The corresponding elements of the LTE network described in the example operate in a similar manner. It should be understood that... Figure 2 The operational aspects of the telecommunications network shown, as well as other networks discussed herein in conjunction with embodiments of this disclosure (e.g., specific communication protocols and physical channels for communication between different elements) not specifically described, can be implemented according to any known technology, such as methods currently used to implement such operational aspects of wireless communication systems, or according to relevant standards.

[0027] Figure 2The TRP 10 in the new RAT network may partially have functions corresponding to a base station or eNodeB in an LTE network. Similarly, the communication device 14 may have functions corresponding to a UE device 4 known for operation in an LTE network. Therefore, it should be understood that operational aspects of the new RAT network (e.g., the specific communication protocols and physical channels used for communication between different elements) may differ from those known to LTE or other known mobile communication standards. However, it should also be understood that each of the core network components, base stations, and communication devices in the new RAT network will be functionally similar to the core network components, base stations, and communication devices of an LTE wireless communication network, respectively.

[0028] In terms of broad top-level functionality, connecting to Figure 2 The core network 20 of the new RAT telecommunications system shown can be roughly considered to be the same as... Figure 1 Corresponding to the core network 2 shown, and the corresponding central unit 40 and its associated distributed unit / TRP10 can be roughly considered to provide the same... Figure 1 The functions corresponding to base station 1. The term network infrastructure equipment / access node can be used to cover these elements as well as more traditional types of base station elements in wireless telecommunications systems. Depending on the current application, the responsibility for scheduling planned transmissions on the radio interface between the corresponding distributed unit and the communication device may be borne by the control node / central unit and / or distributed unit / TRP. Figure 2 Communication device 14 is shown within the coverage area of ​​the first communication cell 12. Thus, communication device 14 can exchange signaling with the first central unit 40 in the first communication cell 12 via one of the distributed units / TRPs 10 associated with the first communication cell 12.

[0029] It should be further understood that Figure 2 This is merely an example of a proposed architecture for a telecommunications system based on the new RAT, in which methods consistent with the principles described herein can be employed, and the functionality disclosed herein can also be applied to wireless telecommunications systems with different architectures.

[0030] Therefore, certain embodiments of this disclosure, as discussed herein, can be implemented in wireless telecommunications systems / networks according to various different architectures, such as... Figure 1 and Figure 2 The example architecture is shown. Therefore, it should be understood that the specific wireless telecommunications architecture in any given implementation is not primary to the principles described herein. In this regard, certain embodiments of this disclosure can be described holistically in the context of communication between network infrastructure devices / access nodes and communication devices, wherein the specific nature of the network infrastructure devices / access nodes and communication devices will depend on the network infrastructure currently implemented. For example, in some scenarios, the network infrastructure devices / access nodes may include base stations, such as… Figure 1The LTE-type base station 1 shown is adapted to provide functionality according to the principles described herein; in other examples, network infrastructure equipment may include Figure 2 The central unit / control node 40 and / or TRP 10 of the type shown are adapted to provide functionality in accordance with the principles described herein.

[0031] Figure 3 Provided Figure 2 A more detailed schematic diagram of some components of the network is shown. Figure 3 In, such as Figure 2 The TRP10 shown, in simplified representation, includes a wireless transmitter 30, a wireless receiver 32, and a controller or control processor 34, which can operate to control the transmitter 30 and the wireless receiver 32 to transmit and receive radio signals to one or more UEs 14 within the cell 12 formed by the TRP 10. Figure 3 As shown, example UE 14 is shown to include a corresponding transmitter 49, receiver 48, and controller 44. Controller 44 is configured to control transmitter 49 and receiver 48 to transmit signals representing uplink data to the wireless communication network via the radio access interface formed by TRP 10, and to receive downlink data as signals transmitted by transmitter 30 and received by receiver 48 in accordance with normal operation.

[0032] Transmitters 30, 49 and receivers 32, 48 (and other transmitters, receivers, and transceivers described in conjunction with examples and embodiments of this disclosure) may include radio frequency filters and amplifiers, as well as signal processing components and means for transmitting and receiving radio signals, for example, according to 5G / NR standards. Controllers 34, 44 (and other controllers described in conjunction with examples and embodiments of this disclosure) may be, for example, microprocessors, CPUs, or dedicated chipsets, configured to execute instructions stored on a computer-readable medium such as non-volatile memory. The various processing steps described herein may, for example, be executed by a microprocessor in conjunction with random access memory according to instructions stored on a computer-readable medium. For ease of illustration, the transmitters, receivers, and controllers are... Figure 3 These are schematically shown as independent elements. However, it should be understood that the functionality of these elements can be provided in a variety of different ways, such as using one or more appropriately programmed programmable computers, or one or more appropriately configured application-specific integrated circuits / circuit systems / chips / chipsets. As will be understood, infrastructure equipment / TRP / base stations and UE / communication devices will typically include a variety of other elements associated with their operational functionality.

[0033] like Figure 3As shown, TRP 10 also includes a network interface 50, which is connected to DU 42 via physical interface 16. Therefore, network interface 50 provides a communication link for data and signaling services from TRP 10 to the core network 20 via DU 42 and CU 40.

[0034] The interface 46 between DU 42 and CU 40 is called the F1 interface, which can be a physical interface or a logical interface. The F1 interface 46 between CU and DU can operate according to 3GPP technical specifications [2] and [3] and can be formed by fiber optic or other wired or wireless high-bandwidth connections. In one example, the connection 16 from TRP 10 to DU 42 is via fiber optic. The connection between TRP 10 and core network 20 can generally be referred to as the backhaul, which includes the interface 16 from network interface 50 of TRP 10 to DU 42 and the F1 interface 46 from DU 42 to CU 40.

[0035] As those familiar with 5G architecture will understand, CU 40 can be a logical node hosting the Radio Resource Control (RRC) protocol, Serving Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) of a gNB. Alternatively, CU 40 can be a logical node hosting the RRC and PDCP protocols of an en-gNB (an en-gNB is a gNB capable of simultaneously connecting to an EPC and an eNB, and can be understood as, for example, a secondary node (SgNB) used in dual-connectivity scenarios). CU 40 partially controls the operation of one or more DU 40s and terminates the F1 interface 46 for the DUs it controls. DU 42 can be a logical node hosting the Radio Link Control (RLC), Media Access Control (MAC), and Physical (PHY) layers of a gNB or en-gNB. The operation of DU 42 is partially controlled by CU 40, and DU 42 terminates the F1 interface 46 for CU 40.

[0036] Although not in Figure 2 or Figure 3As shown in the diagram, but those skilled in the art familiar with 5G architecture will understand, CU 40 can be further divided into CU-CP, which performs the control plane functions of CU 40, and CU-UP, which performs the user plane functions of CU 40 (see, for example, [4]). More specifically, CU-CP may be a logical node of the control plane portion of the RRC and PDCP protocols of CU 40 hosting a gNB or en-gNB. CU-CP terminates the E1 interface connecting to CU-UP and the F1-C interface connecting to DU 42. As will be understood, the F1-C interface carries the control plane signaling of F1 interface 46. CU-UP may be a logical node of the user plane portion of the PDCP protocol of CU 40 hosting an en-gNB. Alternatively, CU-UP may be a logical node of the user plane portion of the PDCP protocol and the SDAP protocol of CU 40 hosting a gNB. CU-UP terminates the E1 interface connecting to CU-CP and the F1-U interface connecting to DU 42. As will be understood, the F1-U interface carries the user plane signaling of F1 interface 46.

[0037] To understand the exemplary implementation, reference will be made to... Figure 4A , Figure 4B and Figure 4C Explanation of the formation as Figure 2 and Figure 3 The diagram shows the protocol stack for a standard F1 interface. Regarding the protocol stack, Figure 4A , Figure 4B and Figure 4C Provided for Figure 2 and Figure 3 This diagram illustrates the processing performed by each element of the packet data communication path 46 between gNB-DU 42 and gNB-CU 40, which is formed via the F1 interface 46. Control plane communication and user plane data are considered separately, although in reality they form the same interface and are processed and transmitted by the same hardware device.

[0038] like Figure 4A As shown, communication is established between gNB DU 42 and gNB CU 40 via F1 interface 46. However, the control plane protocol stack that forms this interface is as follows: Figure 4B As shown, the user plane protocol stack used to transmit user data between gNB-CU 40 and gNB-DU 42 is as follows: Figure 4C As shown. Figure 4B As shown, at the radio network layer, the control plane is formed by the F1 Application Protocol (F1AP) 301a in gNB-CU 40 and the F1 AP 301b in gNB DU 42. As those skilled in the art familiar with 5G architecture will understand, communication between the gNB-CU and gNB DU is conducted via the IPv6 or IPv4 Internet Protocol specified in [5]. This is in Figure 4BThe diagram shows IP layer 302a in gNB-CU 40 and IP layer 302b in gNB-DU 42, forming IP communication interface 302c. The Flow Control Transport Protocol (SCTP) layers 304a, 304b, and 304c of the protocol stack control end-to-end communication via IP layer 302, including flow control and quality of service. IP data is communicated between gNBDU and gNB CU via logical data link layers 306a, 306b, and 306c and physical layers 308a, 308b, and 308c.

[0039] In the user plane, the radio network layer is formed by RLC layers 320a and 320b to create an F1 interface for transmitting user plane data 46. The protocol stack in the transport layer includes the General Packet Radio Service (GPRS) Tunneling Protocol (GTP-U) 322a, 322b, and 322c for user plane data. These protocols control communication of user plane data for roaming and home subscribers via UDP layers 324a, 324b, and 324c, which in turn control user plane data communication via IP layers 326a, 326b, and 326c. Similar to the control plane, IP data communicates between the gNB DU and gNB CU via logical data link layers 328a, 328b, and 328c and physical layers 330a, 330b, and 330c.

[0040] CU-DU Function Division

[0041] As described above, CU 40 and DU 42 are configured to perform gNB functionality. The allocation or division of gNB functionality between CU 40 and DU 42 is discussed in [6]. Such gNB functionality includes: Radio resource management functions: radio bearer control, radio access control, connection mobility control, and dynamic allocation (scheduling) of resources to the UE in the uplink and downlink. IP and Ethernet header compression, data encryption, and integrity protection; When a UE is attached, if the route to the AMF cannot be determined based on the information provided by the UE, the Access and Mobility Management Function (AMF) is selected. Routing user plane data to user plane functions (UPF); Route control plane information to AMF; Connection establishment and release; Scheduling and transmission of paging messages; The scheduling and transmission of system broadcast information (originating from AMF or OAM); Configuration for measurement and measurement reporting for mobility and scheduling; Transport layer packet marking in the uplink; Session management; Supports network slicing; QoS flow management and mapping to data radio bearers; Supports UEs in an RRC_invalid state; NAS message distribution functionality; Radio access network sharing; Dual connection; The close interoperability between NR and E-UTRA; and Maintain the user plane cellular Internet of Things (CIoT) 5GS optimized security and radio configuration as defined in [7] (ng-eNB only).

[0042] All functions listed above (except the last one) can be performed by both gNB and ng-eNB, except for the last function which relates to maintenance security and radio configuration, which is performed only by ng-eNB. As those skilled in the art will understand, ng-eNB is an eNB that connects a 5G UE to the 5G core network using the 4G LTE air interface. In addition, low-complexity (BL) UEs with reduced bandwidth or UEs in enhanced coverage are supported only by ng-eNB (see, for example, [8]). Furthermore, NB-IoT UEs are supported only by ng-eNB (see, for example, [8]).

[0043] As will be understood, 5G networks are currently deployed in the millimeter-wave band. However, the need for higher-frequency wireless communication in 5G networks increases due to the higher communication bandwidth achievable at higher frequencies. Using higher frequencies in wireless communication leads to increased path loss, resulting in smaller cell sizes compared to lower frequencies. Consequently, denser network deployment may be required to achieve adequate coverage.

[0044] For reference as follows Figure 2 and Figure 3As explained, dense network deployment presents several technical challenges to the current 5G architecture. For example, as mentioned earlier, DU 42 and CU 40 can be connected via wired connection 46 (e.g., fiber optic). Therefore, dense network deployment may increase the number of required wired connections, which may not always be feasible. Furthermore, using wired connection 46 between CU 40 and DU may lead to increased latency due to the current topology design. For example, from... Figure 2 It is understood that the two DUs 41 and 42 are connected to CU 40 in a "tree topology" via wired connection 46. Therefore, if any direct signaling is required between the two cells 12 (e.g., one cell is provided by DU 41 and the other by DU 42), such signaling must be propagated through CU 40. This can lead to congestion and increased latency, especially when a large number of cells are deployed in close proximity (e.g., in dense deployment scenarios).

[0045] In addition, the following will refer to Figure 5 To elaborate further, higher cell density presents technical challenges in terms of cell mobility and interference management. Figure 5 The current 5G architecture illustrates the functional division of gNB across CU-CP 40a, CU-UP 40b, and DU 42. CU-CP 40a and CU-UP 40b are implementation references. Figure 2 , Figure 3 And the logical nodes of the CU 40 function illustrated in Figure 4. (As shown...) Figure 5 As shown, CU-CP 40a is configured to perform Radio Resource Management (RRM) function 402, Radio Resource Control (RRC) function 403, Packet Data Convergence Protocol Control Plane (PDCP-CP) function 404, Security function 406, Non-Access Stratum (NAS) function 408, User Equipment (UE) Context function 410, and Quality of Service (QoS) function 412. CU-UP 40b is configured to perform Packet Data Convergence Protocol User Plane (PDCP-UP) function 414. DU 42 is configured to perform RLC function 416, MAC function 418, and PHY function 420. As understood, the scheduler in DU 42 may be implemented based on the guidelines mentioned in Section 10 of [6].

[0046] Layer 1 / Layer 2 Triggered Mobility (LTM)

[0047] Version 18 of the 3GPP standard specifies L1 / 2 triggered mobility (LTM) within a CU (including both within and between DUs). LTM can also stand for "lower-layer triggered mobility." The operation of LTM itself will be explained in more detail in the following paragraphs, but in short (as will be well understood by those skilled in the art), LTM refers to UE mobility entirely controlled by Layer 1 (physical layer) and Layer 2 (data link layer) of the 5G protocol stack. Intra-DU and inter-DU LTM (both within the CU) can be found in [reference needed]. Figure 6 To understand. For example... Figure 6 As shown in the example, two DUs 62 and 63 are connected to a single CU 61. Each DU 62 and 63 supports two cells: DU 62 supports cells 64 and 65, while DU 63 supports cells 66 and 67. In intra-CU LTM, the UE hands over between the source cell and the target cell, both of which are governed by the same CU (e.g., ...). Figure 6 The handover is controlled by CU 61 (via the same or separate DU). For intra-DU LTM, handover can be triggered and controlled by Layer 1 and Layer 2 when the UE is located between cells 64 and 65 (controlled by the same DU 62) or between cells 66 and 67 (controlled by the same DU 63). For inter-DU LTM, handover can be triggered and controlled by Layer 1 and Layer 2 when the UE is located between one of cells 64 and 65 (controlled by DU 62) and one of cells 66 and 67 (controlled by DU 63)—for example, inter-DU LTM may involve the UE handing over from cell 67 to cell 64. As of the priority date of this disclosure, inter-CU LTM is not specified in the 3GPP standard, but it is expected to be specified in version 19 of the 3GPP standard.

[0048] The LTM proposal message sequence is as follows: Figure 7 As shown, this figure is copied from [9]. Figure 7 The detailed process of LTM shown is described in [9], and for better understanding of LTM, such descriptions in the following paragraphs are copied from [9].

[0049] In step 1, UE 71 (in RRC_connection mode) sends a measurement message to gNB 72. gNB 72 decides to use LTM and initiates candidate cell preparation. In step 2, gNB 72 transmits an RRC reconfiguration message to UE 71, which includes the LTM candidate cell configuration for one or more candidate cells. In step 3, UE 71 stores the LTM candidate cell configuration and transmits an RRC reconfiguration complete message to gNB 72. In step 4a, UE 71 may perform DL synchronization with the candidate cell before receiving a cell handover command, and in step 4b, UE 71 may perform advance timing advance (TA) acquisition with the candidate cell before receiving a cell handover command. This is accomplished via contention-free random access (CFRA) triggered by a Physical Downlink Control Channel (PDCCH) command from the source cell, after which UE 71 sends a preamble to the candidate cell. Information identifying the allocated CFRA resources can be indicated in the PDCCH command to enable shared preamble resources among multiple UE 71s. To minimize source cell data interruption caused by performing CFRA on candidate cells, UE 71 either receives a Random Access Response (RAR) from the source cell (not the candidate cell) or does not receive a RAR at all. Whether a RAR is required is configured by the network and is specific to each candidate cell. If a RAR is not required, the TA value of the candidate cell is indicated in the cell handover command. In step 5, UE 71 performs L1 measurements on the configured candidate cells and transmits a lower-layer measurement report to gNB 72. Then, in step 6, gNB 72 decides to perform a cell handover to the target cell and transmits the MAC control element (CE) that triggers the cell handover, including the candidate configuration index of the target cell. UE 71 switches to the configuration of the target cell. In step 7, if the cell handover requires performing such a random access procedure, UE 71 performs a random access procedure on the target cell. Finally, in step 8, UE 71 completes the LTM cell handover procedure by sending an RRC reconfiguration complete message to the target cell. For LTM based on the Random Access Channel (RACH), UE 71 considers the LTM execution process to be successfully completed when the random access procedure itself is successfully completed. For LTM without RACH, UE 71 considers the LTM execution process to be successfully completed when it determines that the network has successfully received its first UL data. UE 71 can perform multiple LTM cell handovers based on the configuration provided in step 2. Figure 7 Steps 4 to 8 are shown.

[0050] Although LTM has already been addressed at a high level, such as Figure 7The message sequences shown are abstract, but in practice, LTM will only execute under certain conditions, and these conditions should be evaluated by the UE. The signaling details between the gNB and the UE regarding these conditions remain unclear. Furthermore, at the current level of detail, these proposals may lead to unnecessary resource reservations and network utilization, resulting in inefficiency. The embodiments of this disclosure aim to provide solutions to these problems.

[0051] Figure 8 An example of this disclosure is shown. Figure 8 In this process, gNB 120 (more generally, infrastructure equipment) transmits LTM configuration 81 to UE 110 (more generally, communication device). gNB 120 provides the source cell to which UE 110 is connected. LTM configuration 81 can be transmitted in various forms. For example, LTM configuration 81 can be transmitted using RRC signaling between gNB 120 and UE 110; however, it should be understood that LTM configuration 81 can also be transmitted in other forms. LTM configuration 81 may include various information related to the LTM procedure (i.e., migration or handover) for UE 110. For example, LTM configuration 81 may include indications of one or more candidate target cells provided by one or more candidate target gNBs (more generally, target infrastructure equipment). These one or more candidate target cells may be a set of cells to which UE 110 can migrate and may be determined by gNB 120. The gNB120 can determine the one or more candidate target cells in a variety of different ways, such as based on the location of the UE 110, the coverage area of ​​the candidate target cells, the trajectory of the UE 110, the connection history of the UE, and / or one or more other factors. Furthermore, the gNB120 can determine the one or more candidate target cells based on signaling from one or more other gNBs providing cells (e.g., via the F1 and / or Xn interfaces). Such inter-gNB signaling can, for example, indicate the current congestion level of the other gNBs, the number of devices connected to the other gNBs, or one or more other metrics indicating the ability of the other gNBs to support the migration of the UE 110 to the respective cells of the other gNBs.

[0052] LTM configuration 81 may, in some cases, indicate specific resources for each candidate target cell. For example, LTM configuration 81 may indicate one or more RACH preambles for the corresponding candidate target cell, and / or authorization for the configuration of the RRC reconfiguration completion message to be transmitted by UE 110 after LTM completion. Furthermore, LTM configuration 81 may include a resource reservation timer for each candidate target cell. The resource reservation timer may indicate the remaining duration for which resources are reserved on the corresponding candidate target cell for UE 110 migration. For example, the resource reservation timer may indicate the remaining duration for which a particular RACH preamble is valid (i.e., accepted by the corresponding candidate target cell), and / or the remaining duration for which authorization for the configuration of the RRC reconfiguration completion message or user data is reserved. gNB 120 may determine the resource reservation timer based on signaling from the corresponding candidate target cell. For example, before gNB 120 transmits LTM configuration 81 to UE 110, each candidate target cell may indicate its timer to gNB 120. By instructing the UE 110 to reserve a resource timer, resources can be reserved on the candidate target cell for a limited period of time, and since the UE 110 is aware of this time, the over-reservation of candidate target cell resources can be reduced.

[0053] LTM configuration 81 may additionally or alternatively include details of measurements to be performed by UE 110. These measurements may be so-called Layer 1 (L1) measurements or physical measurements, and may include, for example, the signal strength of one or more candidate target cells (e.g., the signal strength of one or more reference signals) and / or the signal strength of the source cell (e.g., the signal strength of one or more reference signals).

[0054] exist Figure 8 In the example, LTM configuration 81 includes one or more LTM execution conditions for the LTM procedure. That is, LTM configuration 81 can indicate that UE 110 should initiate an LTM procedure when the one or more LTM execution conditions are met. As an example, the one or more execution conditions could be: the signal strength of the candidate target cell is higher than the signal strength of the serving cell by a specific amount, and / or the signal strength of the candidate target cell is greater than a predetermined threshold.

[0055] After receiving LTM configuration 81, UE 110 may (e.g., periodically) perform 82 L1 measurements (e.g., as indicated in LTM configuration 81). During or after performing the L1 measurements, UE 110 may evaluate whether one or more LTM execution conditions are met. In other words, UE 110 may compare the results of the L1 measurements with the one or more LTM execution conditions and determine whether to initiate an LTM procedure to migrate to a specific candidate target cell. Based on this comparison, UE 110 may decide not to perform the LTM procedure if it determines that one or more LTM execution conditions are not met. Alternatively, UE 110 may determine that it should migrate to a specific candidate target cell based on the one or more LTM execution conditions being met for that candidate target cell. In other words, UE 110 can select a specific candidate target cell as the target cell for the LTM procedure (i.e., migration / handover). UE 110 may select the target cell based on various factors. For example, UE 110 may select the target cell based on L1 measurements. UE 110 may additionally or alternatively select a target cell based on local auxiliary information. Local auxiliary information may include information known to the UE but unknown to the network, such as the UE 110's connection history, trajectory, and / or based on input from an AI model.

[0056] After identifying the LTM target cell, UE 110 initiates (i.e., executes) LTM procedure 83 to migrate UE 110's connection to the target cell. Executing LTM procedure 83 may include performing a RACH procedure with the target cell (e.g., by transmitting a RACH preamble to the target cell). Alternatively, to execute LTM procedure 83, UE 110 may perform an LTM procedure without RACH with the target cell. During the execution of LTM procedure 83, UE 110's connection can be migrated from the source cell provided by gNB 120 to the target cell. Therefore, according to... Figure 8 As shown in the example, the UE can determine whether it should perform LTM based on one or more LTM execution conditions indicated in the LTM configuration message. This provides a mechanism that allows the UE to know when to perform LTM with minimal network signaling.

[0057] Figure 9 Another example according to this disclosure is shown. Figure 9 In this example, gNB 120 (more generally, infrastructure equipment) transmits LTM configuration 91 to UE 110 (more generally, communication device). LTM configuration 91 in this example may include the information above regarding... Figure 8 The LTM configuration discussed in section 81 differs from any other information. Figure 9The LTM configuration 91 does not include any LTM execution conditions for the LTM procedure. Instead, the LTM configuration 91 includes indications for one or more reporting conditions, based on which, when the one or more reporting conditions are met, the UE 110 should transmit an indication of the L1 measurement performed by the UE 110 to the gNB 120. The one or more reporting conditions may be based on L1 measurements; for example, the one or more reporting conditions may include the signal strength of the candidate target cell being higher than the signal strength of the serving cell by a specific amount, and / or the signal strength of the candidate target cell being greater than a predetermined threshold. Additionally or alternatively, the one or more reporting conditions may be based on one or more additional factors.

[0058] After receiving the LTM configuration 91, UE 110 performs an L1 measurement 92. UE 110 also evaluates whether one or more reporting conditions are met. If UE 110 determines that one or more reporting conditions are met, UE 110 transmits an L1 measurement indication 93 to gNB 120. The L1 measurement indication 93 may include an indication of L1 measurement performed for each candidate target cell, or an indication of L1 measurement performed only for a subset of candidate target cells (such as target cells for which one or more reporting conditions are met). In addition to the indication of the L1 measurement itself, UE 110 may also indicate additional information, such as preferred target cells, (in the same message or separately). UE 110 may determine preferred target cells based on L1 measurement 92 and / or one or more additional factors. For example, UE 110 may determine preferred target cells based on local auxiliary information. UE 110 may indicate multiple preferred target cells to gNB 120, and in some cases may order the preferred target cells in order of priority.

[0059] In response to receiving an instruction 93 from UE 110 regarding an L1 measurement, gNB 120 determines whether UE 110 should perform an LTM procedure. That is, gNB 120 may determine that UE 110 should perform LTM, select a target cell from the candidate target cells, and transmit an instruction 94 to UE 110 to perform LTM on that target cell. gNB 120 may select a target cell based on the L1 measurement indicated by UE 110. Additionally or alternatively, gNB 120 may select a target cell based on one or more other factors, which may be unknown to UE 110, such as the current congestion level of the candidate target cell, the number of devices connected to the candidate target cell, or one or more other metrics indicating the ability of the candidate target cell to support migration of UE 110 to the corresponding candidate target cell. Additionally or alternatively, UE 110 may transmit an indication of local auxiliary information to gNB 120 (e.g., along with an indication of L1 measurement, or separately), and gNB 120 may additionally select a target cell based on the local auxiliary information. Based on the determination that UE 110 should perform LTM and select a target cell, gNB 120 transmits instruction 94 to UE 110 to instruct UE 110 to perform LTM to the selected target cell. UE 110 can then perform LTM 95 to the target cell. In some cases, gNB 120 may determine that UE 110 should not perform LTM. Therefore, gNB 120 may determine not to transmit LTM instruction 94 to UE 110, or may transmit an instruction not to perform LTM to UE 110. LTM instruction 94 may additionally or alternatively include a resource reservation timer indicating the duration for which resources are reserved on the target cell for UE 110's migration.

[0060] according to Figure 9 For example, the UE can therefore perform LTM in a way that provides the network with control over the UE's target cell, but in a way that requires low resource consumption and low network signaling.

[0061] Figure 10 Another example according to this disclosure is shown. Figure 10 In the process, gNB 120 sends LTM configuration 101 to UE 110, and the UE performs L1 measurement 102, such as... Figure 9 Like in the middle. Figure 10 Examples and Figure 9 The examples are basically similar, except that instead of sending an indication of the L1 measurement being performed (such as...),... Figure 9As in the previous example), UE 110 may alternatively send a request 103 to gNB 120 to perform LTM. In some cases, LTM request 103 may be in the form of a MAC CE. MAC CE may include a target configuration identifier (ID) for a preferred target cell, which corresponds to an LTM configuration index included in LTM configuration 101. Therefore, gNB 120 may be informed of UE 110's preferred target cell based on the target cell's configuration ID (indicated in LTM configuration 101). In some cases, the LTM request may indicate configuration IDs for multiple preferred target cells (each indicated in LTM configuration 101), and gNB 120 may select a target cell from the multiple preferred target cells (such as in the manner already described above).

[0062] exist Figure 10 In this example, gNB 120 (more generally, infrastructure equipment) sends LTM configuration 101 to UE 110 (more generally, communication device). LTM configuration 101 in this example may include the information above regarding... Figure 8 LTM configuration 81 or Figure 9 Any information regarding the LTM configuration discussed in 91, the difference being... Figure 10 LTM configuration 101 does not include any LTM execution conditions for the LTM procedure. Instead, LTM configuration 91 includes an indication of one or more LTM request conditions, based on which UE 110 should send a request 103 to gNB 120 to perform LTM when one or more LTM request conditions are met.

[0063] LTM configuration 101 may indicate one or more LTM request conditions, and based on the satisfaction of the request conditions, UE 110 may send request 103 to gNB 120. Request 103 may indicate to gNB 120 that one or more LTM request conditions have been satisfied, and may indicate one or more preferred candidate target cells. In some cases, the LTM request may indicate only a single target cell (determined by UE 110), and LTM instruction 104 may not indicate any target cell, and UE 110 performs LTM on the target cell indicated in LTM request 103 based on the received LTM instruction. In some cases, request 103 may include an indication of L1 measurement; however, in other examples, request 103 may not include an indication of L1 measurement. Figure 10 The gNB120 can send an instruction 104 to the UE 110 to perform LTM. Based on the received LTM instruction 104, the UE 110 then performs LTM for the target cell, as described above.

[0064] according to Figure 9For example, the UE can therefore perform LTM in a way that provides the network with control over the UE's target cell, but in a way that requires low resource consumption and low network signaling.

[0065] Figure 11 This is a flowchart illustrating a method for a communication device according to an example of this disclosure. Step S111 includes receiving Low-Layer Triggered Mobility (LTM) configuration information from a source infrastructure device providing a source cell, wherein the LTM configuration information includes indications for one or more conditions for the communication device to migrate to a target cell provided by a target infrastructure device, wherein the one or more conditions are based on measurements to be performed by the communication device. Step S112 includes performing the measurements indicated in the LTM configuration. Step S113 includes initiating an LTM procedure for migration to the target cell based on the measurements and one or more conditions.

[0066] Figure 12 This is a flowchart illustrating a method for a communication device according to an example of this disclosure. Step S121 includes receiving Low-Layer Triggered Mobility (LTM) configuration information from a source infrastructure device, wherein the LTM configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements indicated in the LTM configuration to be performed by the communication device. Step S122 includes performing the measurements indicated in the LTM configuration. Step S123 includes sending the measurement indications to the source infrastructure device and / or a request to perform an LTM procedure for migration to a target cell. Step S124 includes receiving an LTM command from the source infrastructure device, the LTM command including instructions to initiate an LTM procedure for migration to the target cell. Step S125 includes initiating an LTM procedure for migration to the target cell.

[0067] Figure 13 This is a flowchart illustrating a method for an infrastructure device according to an example of this disclosure. Step S131 includes sending Low-Layer Triggered Mobility (LTM) configuration information to a communication device, wherein the LTM configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM configuration. The LTM configuration information may indicate one or more conditions for the communication device to initiate an LTM procedure for migration to a target cell provided by the target infrastructure device, or the LTM configuration information may indicate one or more conditions for the communication device to send an indication of measurement to the infrastructure device and / or to execute a request for the LTM procedure for migration to the target cell. Step S132 is an optional step, including receiving from the communication device an indication of a measurement to be performed by the communication device and / or to execute a request for the LTM procedure for migration to the target cell, and step S133 is an optional step, including sending an LTM command to the communication device, the LTM command including instructions to initiate an LTM procedure for migration to the target cell.

[0068] Therefore, from one perspective, a communication device, infrastructure equipment, and method of operating such a device for efficiently handling mobility processes in such a wireless communication network have been described. The infrastructure equipment can send a Layer 1 / Layer 2 triggered mobility (LTM) configuration to the communication device via RRC signaling, indicating one or more conditions for the communication device to perform LTM, request LTM, or report measurements to the infrastructure equipment. The communication device can then perform LTM based on the conditions being met or based on receiving an instruction to perform LTM.

[0069] Further examples of this disclosure are set forth in the following numbered clauses: 1. A method of operating a communication device configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless access interface, the method comprising: Receive Low-Layer Triggered Mobility (LTM) candidate configuration information from the source infrastructure equipment providing the source cell, wherein the LTM candidate configuration information includes indications of at least one or more conditions for the communication device to migrate to the target cell provided by the target infrastructure equipment, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurements indicated in the LTM candidate configuration information; and Based on measurements and one or more conditions, initiate an LTM procedure for migration to the target cell.

[0070] 2. The method according to Clause 1, wherein the LTM candidate configuration information indicates one or more conditions for the communication device to initiate the LTM procedure.

[0071] 3. The method according to Clause 2, wherein, relative to the source cell provided by the source infrastructure equipment, one or more conditions are based on physical layer measurements of one or more candidate target cells provided by one or more candidate target infrastructure equipment, wherein the one or more candidate target cells include the target cell.

[0072] 4. A method for a communication device, the method comprising: Receive Low-Layer Triggered Mobility (LTM) candidate configuration information from source infrastructure equipment, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurements indicated in the LTM candidate configuration information; Send measurement instructions to the source infrastructure equipment and / or request the execution of an LTM procedure for migration to a target cell provided by the target infrastructure equipment; Receive LTM commands from source infrastructure equipment, the LTM commands including instructions to initiate an LTM procedure for migration to the target cell; and Initiate the LTM procedure for migration to the target cell.

[0073] 5. The method according to Clause 4, wherein the LTM command includes a resource reservation timer, wherein the resource reservation timer indicates the duration for which resources are reserved on one or more candidate target cells provided by one or more candidate target infrastructure devices.

[0074] 6. The method according to Clause 4 or 5, wherein the indication of measurement and / or the request to perform the LTM procedure for migration to the target cell indicates one or more preferred target cells from one or more candidate target cells provided by one or more candidate target infrastructure devices.

[0075] 7. The method according to Clause 6, wherein the UE identifies one or more preferred target cells based at least in part on local auxiliary information.

[0076] 8. The method according to Clause 7, wherein the local auxiliary information includes one or more of the following: the connection history of the communication device, the trajectory of the communication device, and an artificial intelligence model implemented on the communication device.

[0077] 9. The method according to any one of Clauses 4 to 8, wherein the request to perform the LTM procedure is included in the Media Access Control (MAC) control element (CE).

[0078] 10. The method according to Clause 9, wherein the MAC CE includes the target configuration ID of a preferred target cell among one or more candidate target cells provided by one or more candidate target infrastructure devices, wherein the target configuration ID is identified in LTM candidate configuration information received from the source infrastructure device.

[0079] 11. The method according to any one of Clauses 4 to 10, wherein the LTM candidate configuration information indicates one or more conditions for the communication device to send an instruction for measurement and / or to perform an LTM procedure for migration to the target cell.

[0080] 12. The method according to any of the preceding clauses, wherein initiating the LTM procedure includes initiating a random access channel (RACH) procedure with the target infrastructure equipment.

[0081] 13. The method according to any of the preceding clauses, wherein initiating the LTM procedure includes initiating an attachment procedure with the target infrastructure equipment without a random access channel (RACH).

[0082] 14. The method according to any of the preceding clauses, wherein the LTM candidate configuration information includes a resource reservation timer, wherein the resource reservation timer indicates the duration for which resources are reserved on one or more candidate target cells provided by one or more candidate target infrastructure devices.

[0083] 15. The method according to Clause 14, wherein the resources reserved on one or more candidate target cells include random access (RACH) resources and / or authorization for configuration of radio resource control (RRC) reconfiguration completion messages or user data.

[0084] 16. The method according to any of the preceding clauses, wherein LTM candidate configuration information is included in radio resource control (RRC) signaling.

[0085] 17. The method according to any of the preceding clauses, wherein the LTM candidate configuration information includes the identifiers of one or more candidate target cells provided by one or more candidate target infrastructure devices.

[0086] 18. The method according to Clause 17, wherein the LTM candidate configuration information includes an indication of the resources reserved on each of one or more candidate target cells.

[0087] 19. A communication device configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless radio interface provided by the wireless communication network, the communication device comprising: The transmitter is configured to transmit signals. The receiver is configured to receive signals, and The controller is configured to work in conjunction with the transmitter and receiver to perform the following operations: Receive Low-Layer Triggered Mobility (LTM) candidate configuration information from the source infrastructure equipment providing the source cell, wherein the LTM candidate configuration information includes at least an indication of one or more conditions for the communication device to migrate to the target cell provided by the target infrastructure equipment, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information. Perform the measurements indicated in the LTM candidate configuration information; and Based on measurements and one or more conditions, initiate an LTM procedure for migration to the target cell.

[0088] 20. A communication device configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless radio interface provided by the wireless communication network, the communication device comprising: The transmitter is configured to transmit signals. The receiver is configured to receive signals, and The controller is configured to work in conjunction with the transmitter and receiver to perform the following operations: Receive Low-Layer Triggered Mobility (LTM) candidate configuration information from source infrastructure equipment, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurements indicated in the LTM candidate configuration information; Send measurement instructions to the source infrastructure equipment and / or requests to perform the LTM process for migration to the target cell provided by the target infrastructure equipment; Receives LTM commands from the source infrastructure equipment, including instructions for initiating an LTM process to migrate to the target cell; and Initiate the LTM procedure for migration to the target cell.

[0089] 21. A circuit for a communication device configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless radio interface provided by the wireless communication network, the circuit comprising: The transmitter circuit is configured to transmit signals. The receiver circuit is configured to receive signals, and The controller circuitry is configured to combine with the transmitter and receiver circuitry to perform the following operations: Receive Low-Layer Triggered Mobility (LTM) candidate configuration information from the source infrastructure equipment providing the source cell, wherein the LTM candidate configuration information includes at least an indication of one or more conditions for the communication device to migrate to the target cell provided by the target infrastructure equipment, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information. Perform the measurements indicated in the LTM candidate configuration information; and Based on measurements and one or more conditions, initiate an LTM procedure for migration to the target cell.

[0090] 22. A circuit for a communication device configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless radio interface provided by the wireless communication network, the circuit comprising: The transmitter circuit is configured to transmit signals. The receiver circuit is configured to receive signals, and The controller circuit, combined with the transmitter and receiver circuits, performs the following operations: Receive Low-Layer Triggered Mobility (LTM) candidate configuration information from source infrastructure equipment, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurements indicated in the LTM candidate configuration information; Send measurement instructions to the source infrastructure equipment and / or requests to perform the LTM process for migration to the target cell provided by the target infrastructure equipment; Receives LTM commands from the source infrastructure equipment, including instructions for initiating an LTM process to migrate to the target cell; and Initiate the LTM procedure for migration to the target cell.

[0091] 23. A method for infrastructure equipment configured to transmit signals to and / or receive signals from one or more communication devices of a wireless communication network via a wireless radio interface provided by the wireless communication network, the method comprising: Send Low-Layer Triggered Mobility (LTM) candidate configuration information to the communication device, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information, wherein: LTM candidate configuration information indicates one or more conditions for a communication device to initiate a migration to an LTM process provided by the target infrastructure equipment, or LTM candidate configuration information indicates one or more conditions used by the communication device to send measurement instructions to the infrastructure equipment and / or to request the execution of an LTM procedure to the target cell.

[0092] 24. The method according to Clause 23, wherein the LTM candidate configuration information indicates one or more conditions for the communication device to initiate the LTM procedure.

[0093] 25. The method according to Clause 24, wherein, relative to a source cell provided by a source infrastructure device, one or more conditions are based on physical measurements of one or more candidate target cells provided by one or more candidate target infrastructure devices, wherein the one or more candidate target cells include a target cell.

[0094] 26. The method pursuant to Clause 23 also includes: Receive instructions from the communication device regarding measurements performed by the communication device, and / or requests for performing an LTM procedure to migrate to the target cell; and Send an LTM command to the communication device, which includes instructions for initiating an LTM procedure to migrate to the target cell.

[0095] 27. The method according to Clause 26, wherein the LTM command includes a resource reservation timer, wherein the resource reservation timer indicates the duration for which resources are reserved on one or more candidate target cells provided by one or more candidate target infrastructure devices.

[0096] 28. The method according to Clause 26 or 27, wherein the indication of measurement and / or the request for performing the LTM procedure to migrate to the target cell, indicates one or more preferred target cells among one or more candidate target cells provided by one or more candidate target infrastructure devices.

[0097] 29. The method according to any one of Clauses 26 to 28, wherein the request for performing the LTM procedure is included in the Media Access Control (MAC) control element (CE).

[0098] 30. The method according to Clause 29, wherein the MAC CE includes a target configuration ID of a preferred target cell among one or more candidate target cells provided by one or more candidate target infrastructure devices, wherein the target configuration ID is identified in LTM candidate configuration information received from the source infrastructure device.

[0099] 31. The method according to any one of Clauses 26 to 30, wherein the LTM candidate configuration information indicates one or more conditions for an indication of transmission measurement by the communication device and / or for a request to perform an LTM procedure for migration to the target cell.

[0100] 32. The method according to any one of Clauses 23 to 31, wherein initiating the LTM procedure includes initiating a random access (RACH) procedure with the target infrastructure device.

[0101] 33. The method according to any one of Clauses 23 to 32, wherein initiating the LTM procedure includes initiating a random access-free (RACH) attachment procedure to the target infrastructure device.

[0102] 34. The method according to any one of clauses 23 to 33, wherein the LTM candidate configuration information includes a resource reservation timer, wherein the resource reservation timer indicates the duration for which resources are reserved on one or more candidate target cells provided by one or more candidate target infrastructure devices.

[0103] 35. The method according to Clause 34, wherein the resources reserved on one or more candidate target cells include random access (RACH) resources and / or authorization for configuration of Radio Resource Control (RRC) reconfiguration completion messages or user data.

[0104] 36. The method according to any one of clauses 23 to 35, wherein the LTM configuration information is included in the radio resource control (RRC) signaling.

[0105] 37. The method according to any one of Clauses 23 to 36, wherein the LTM configuration information includes the identifiers of one or more candidate target cells provided by one or more candidate target infrastructure devices.

[0106] 38. The method according to Clause 37, wherein the LTM candidate configuration information includes an indication of the resources reserved on each of one or more candidate target cells.

[0107] 39. The method pursuant to Clause 38 also includes: Receive instructions from one or more other infrastructure devices that provide one or more candidate target cells regarding reserved resources for one or more candidate target cells.

[0108] 40. The method pursuant to any one of clauses 23 to 39 further includes: Receive an indication from one or more other infrastructure devices that provide one or more candidate target cells, wherein the resource retention timer indicates the duration for which resources are retained on one or more candidate target cells.

[0109] 41. An infrastructure device for a wireless communication network, the infrastructure device being configured to transmit signals to one or more communication devices and / or receive signals from one or more communication devices via a wireless radio interface provided by the wireless communication network, the infrastructure device comprising: The transmitter is configured to transmit signals. The receiver is configured to receive signals, and The controller is configured to work in conjunction with the transmitter and receiver to perform the following operations: Transmit Low-Layer Triggered Mobility (LTM) candidate configuration information to the communication device, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information, wherein: LTM candidate configuration information indicates one or more conditions for a communication device to initiate a migration to an LTM process provided by the target infrastructure equipment, or LTM candidate configuration information indicates one or more conditions used by the communication device to send measurement instructions to the infrastructure equipment and / or to request the execution of an LTM procedure to the target cell.

[0110] 42. A circuit for an infrastructure device of a wireless communication network, the circuit being configured to transmit signals to one or more communication devices and / or receive signals from one or more communication devices via a wireless radio interface provided by the wireless communication network, the circuit comprising: The transmitter circuit is configured to transmit signals. The receiver circuit is configured to receive signals, and The controller circuitry is configured to combine with the transmitter and receiver circuitry to perform the following operations: Transmit Low-Layer Triggered Mobility (LTM) candidate configuration information to the communication device, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information, wherein: LTM candidate configuration information indicates one or more conditions for a communication device to initiate a migration to an LTM process provided by the target infrastructure equipment, or LTM candidate configuration information indicates one or more conditions for communication devices to transmit measurements to infrastructure equipment and / or for requests to perform LTM procedures for migration to a target cell.

[0111] References

[0112] [1]Holma H. ​​and Toskala A, "LTE for UMTS OFDMA and SC-FDMA basedradio access", John Wiley and Sons, 2009.

[0113] [2]TS 38.470, "3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; NG-RAN; F1 general aspects andprinciples (Release 17)", 3GPP, V17.4.0, March 2023.

[0114] [3]TS 38.473, "3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; NG-RAN; F1 application protocol(F1AP) (Release 17)", 3GPP, V17.4.1, April 2023.

[0115] [4]TS 38.401, "3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; NG-RAN; Architecture description(Release 17)", 3GPP, V17.4.0, March 2023.

[0116] [5]TS 38 472, "3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; NG-RAN; F1 signalling transport(Release 15)", 3GPP, V15.2.0, September 2018.

[0117] [6]TS 38.300, "3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; NR; NR and NG-RAN OverallDescription; Stage 2 (Release 17)", 3GPP, V17.4.0, March 2023.

[0118] [7]TS 23.501, "3rd Generation Partnership Project; TechnicalSpecification Group Services and System Aspects; System architecture for the5G System (5GS); Stage 2 (Release 18)", 3GPP, V18.2.0, June 2023.

[0119] [8]TS 36.300, "3rd Generation Partnership Project; TechnicalSpecification Group Radio Access Network; Evolved Universal Terrestrial RadioAccess (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 17)", 3GPP, V17.4.0, March2023.

[0120] [9]R2-2305305, "Change Request for 38.300 running CR for introductionof NR further mobility enhancements", MediaTek Inc., vivo, 3GPP TSG-RAN WG2Meeting #122, May 2023.

Claims

1. A method of operating a communication device, the communication device being configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless access interface, the method comprising: Receive low-layer triggered mobility (LTM) candidate configuration information from a source infrastructure device providing a source cell, wherein the LTM candidate configuration information includes at least an indication of one or more conditions for the communication device to migrate to a target cell provided by the target infrastructure device, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurement indicated in the LTM candidate configuration information; and Based on the measurements and one or more of the conditions, an LTM procedure for migration to the target cell is initiated.

2. The method according to claim 1, wherein, The LTM candidate configuration information indicates one or more conditions for the communication device to initiate the LTM process.

3. The method according to claim 2, wherein, The one or more conditions are based on physical layer measurements of one or more candidate target cells provided by one or more candidate target infrastructure devices, relative to the source cell provided by the source infrastructure device, wherein the one or more candidate target cells include the target cell.

4. A method for a communication device, the method comprising: Receive low-level triggered mobility (LTM) candidate configuration information from source infrastructure equipment, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurement indicated in the LTM candidate configuration information; Sending instructions for the measurement to the source infrastructure equipment and / or requesting the execution of an LTM procedure for migration to a target cell provided by the target infrastructure equipment; Receive an LTM command from the source infrastructure device, the LTM command including instructions to initiate the LTM procedure for migration to the target cell; and Initiate the LTM procedure for migration to the target cell.

5. The method according to claim 4, wherein, The LTM command includes a resource reservation timer, wherein the resource reservation timer indicates the duration for which resources are reserved on one or more candidate target cells provided by one or more candidate target infrastructure devices.

6. The method according to claim 4, wherein, The measurement indication and / or the request to perform the LTM process for migration to the target cell indicate one or more preferred target cells from one or more candidate target cells provided by one or more candidate target infrastructure devices.

7. The method according to claim 6, wherein, The UE identifies the one or more preferred target cells based at least in part on local auxiliary information.

8. The method according to claim 7, wherein, The local auxiliary information includes one or more of the following: the connection history of the communication device, the trajectory of the communication device, and the artificial intelligence model implemented on the communication device.

9. The method according to claim 4, wherein, The request for performing the LTM procedure is included in the Media Access Control (MAC) control element (CE).

10. The method according to claim 9, wherein, MAC CE includes a target configuration ID of a preferred target cell from one or more candidate target cells provided by one or more candidate target infrastructure devices, wherein the target configuration ID is identified in the LTM candidate configuration information received from the source infrastructure device.

11. The method according to claim 4, wherein, The LTM candidate configuration information indicates one or more conditions for the communication device to send instructions for the measurement and / or to execute an LTM procedure for migration to the target cell.

12. The method according to claim 1, wherein, Initiating the LTM procedure includes initiating a random access channel (RACH) procedure with the target infrastructure device.

13. The method according to claim 1, wherein, Initiating the LTM procedure includes initiating a random access channel (RACH) attachment procedure to the target infrastructure device.

14. The method according to claim 1, wherein, The LTM candidate configuration information includes a resource reservation timer, wherein the resource reservation timer indicates the duration for which resources are reserved on one or more candidate target cells provided by one or more candidate target infrastructure devices.

15. The method according to claim 14, wherein, The resources reserved on the one or more candidate target cells include random access (RACH) resources and / or configuration authorizations for Radio Resource Control (RRC) reconfiguration completion messages or user data.

16. The method according to claim 1, wherein, The LTM candidate configuration information is included in the Radio Resource Control (RRC) signaling.

17. The method according to claim 1, wherein, The LTM candidate configuration information includes the identifiers of one or more candidate target cells provided by one or more candidate target infrastructure devices.

18. The method according to claim 17, wherein, The LTM candidate configuration information includes an indication of the resources reserved on each of the one or more candidate target cells.

19. A communication device configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless radio interface provided by the wireless communication network, the communication device comprising: The transmitter is configured to send signals. The receiver is configured to receive signals, and The controller is configured to work in conjunction with the transmitter and the receiver to perform the following operations: Receive low-layer triggered mobility (LTM) candidate configuration information from a source infrastructure device providing a source cell, wherein the LTM candidate configuration information includes at least an indication of one or more conditions for the communication device to migrate to a target cell provided by the target infrastructure device, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurement indicated in the LTM candidate configuration information; and Based on the measurements and one or more of the conditions, an LTM procedure for migration to the target cell is initiated.

20. A communication device configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless radio interface provided by the wireless communication network, the communication device comprising: The transmitter is configured to send signals. The receiver is configured to receive signals, and The controller is configured to work in conjunction with the transmitter and the receiver to perform the following operations: Receive low-level triggered mobility (LTM) candidate configuration information from source infrastructure equipment, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurement indicated in the LTM candidate configuration information; Sending instructions for the measurement to the source infrastructure equipment and / or requesting the execution of an LTM procedure for migration to a target cell provided by the target infrastructure equipment; Receive an LTM command from the source infrastructure device, the LTM command including instructions to initiate the LTM procedure for migration to the target cell; and Initiate the LTM procedure for migration to the target cell.

21. A circuit for a communication device configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless radio interface provided by the wireless communication network, the circuit comprising: The transmitter circuit is configured to transmit signals. The receiver circuit is configured to receive signals, and The controller circuit is configured to combine with the transmitter circuit and the receiver circuit to perform the following operations: Receive low-layer triggered mobility (LTM) candidate configuration information from a source infrastructure device providing a source cell, wherein the LTM candidate configuration information includes at least an indication of one or more conditions for the communication device to migrate to a target cell provided by the target infrastructure device, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurement indicated in the LTM candidate configuration information; and Based on the measurements and one or more of the conditions, an LTM procedure for migration to the target cell is initiated.

22. A circuit for a communication device configured to transmit signals to and / or receive signals from infrastructure equipment of a wireless communication network via a wireless radio interface provided by the wireless communication network, the circuit comprising: The transmitter circuit is configured to transmit signals. The receiver circuit is configured to receive signals, and The controller circuit is configured to combine with the transmitter circuit and the receiver circuit to perform the following operations: Receive low-level triggered mobility (LTM) candidate configuration information from source infrastructure equipment, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information; Perform the measurement indicated in the LTM candidate configuration information; Sending instructions for the measurement to the source infrastructure equipment and / or requesting the execution of an LTM procedure for migration to a target cell provided by the target infrastructure equipment; Receive an LTM command from the source infrastructure device, the LTM command including instructions to initiate the LTM procedure for migration to the target cell; and Initiate the LTM procedure for migration to the target cell.

23. A method for infrastructure equipment, the infrastructure equipment being configured to transmit signals to and / or receive signals from one or more communication devices of a wireless communication network via a wireless radio interface provided by the wireless communication network, the method comprising: Sending Low-Layer Triggered Mobility (LTM) candidate configuration information to the communication device, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information, wherein: The LTM candidate configuration information indicates one or more conditions for the communication device to initiate an LTM process for migrating to a target cell provided by the target infrastructure equipment, or The LTM candidate configuration information indicates one or more conditions for the communication device to send instructions for the measurement to the infrastructure equipment and / or to execute an LTM procedure for migration to the target cell.

24. The method according to claim 23, wherein, The LTM candidate configuration information indicates one or more conditions for the communication device to initiate the LTM process.

25. The method according to claim 24, wherein, The one or more conditions are based on physical measurements of one or more candidate target cells provided by one or more candidate target infrastructure devices, relative to the source cell provided by the source infrastructure device, wherein the one or more candidate target cells include the target cell.

26. The method of claim 23, further comprising: Receive instructions from the communication device regarding the measurement performed by the communication device and / or a request to perform an LTM procedure for migration to the target cell; as well as Send an LTM command to the communication device, the LTM command including instructions to initiate the LTM process for migration to the target cell.

27. The method according to claim 26, wherein, The LTM command includes a resource reservation timer, wherein the resource reservation timer indicates the duration for which resources are reserved on one or more candidate target cells provided by one or more candidate target infrastructure devices.

28. The method according to claim 26, wherein, The measurement indication and / or request to perform an LTM procedure for migration to the target cell indicates one or more preferred target cells from one or more candidate target cells provided by one or more candidate target infrastructure devices.

29. The method according to claim 26, wherein, The request to perform the LTM procedure is included in the Media Access Control (MAC) control element (CE).

30. The method according to claim 29, wherein, MAC CE includes a target configuration ID of a preferred target cell from one or more candidate target cells provided by one or more candidate target infrastructure devices, wherein the target configuration ID is identified in the LTM candidate configuration information received from the source infrastructure device.

31. The method according to claim 26, wherein, The LTM candidate configuration information indicates one or more conditions for the communication device to send instructions for the measurement and / or to execute an LTM procedure for migration to the target cell.

32. The method according to claim 23, wherein, Initiating the LTM procedure includes initiating a random access (RACH) procedure with the target infrastructure device.

33. The method according to claim 23, wherein, Initiating the LTM procedure includes initiating a random access-free (RACH) attachment procedure with the target infrastructure device.

34. The method according to claim 23, wherein, The LTM candidate configuration information includes a resource reservation timer, wherein the resource reservation timer indicates the duration for which resources are reserved on one or more candidate target cells provided by one or more candidate target infrastructure devices.

35. The method according to claim 34, wherein, The resources reserved on the one or more candidate target cells include random access (RACH) resources and / or configuration authorizations for Radio Resource Control (RRC) reconfiguration completion messages or user data.

36. The method according to claim 23, wherein, LTM configuration information is included in the Radio Resource Control (RRC) signaling.

37. The method according to claim 23, wherein, LTM configuration information includes the identifiers of one or more candidate target cells provided by one or more candidate target infrastructure devices.

38. The method according to claim 37, wherein, The LTM candidate configuration information includes an indication of the resources reserved on each of the one or more candidate target cells.

39. The method of claim 38, further comprising: Receive an indication from one or more other infrastructure devices that provide the one or more candidate target cells for reserved resources for the one or more candidate target cells.

40. The method of claim 23, further comprising: Receive an indication from one or more other infrastructure devices that provide one or more candidate target cells, wherein the resource retention timer indicates the duration for which resources are retained on the one or more candidate target cells.

41. An infrastructure device for a wireless communication network, the infrastructure device being configured to transmit signals to one or more communication devices and / or receive signals from the one or more communication devices via a wireless radio interface provided by the wireless communication network, the infrastructure device comprising: The transmitter is configured to send signals. The receiver is configured to receive signals, and The controller is configured to work in conjunction with the transmitter and the receiver to perform the following operations: Sending Low-Layer Triggered Mobility (LTM) candidate configuration information to the communication device, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information, wherein: The LTM candidate configuration information indicates one or more conditions for the communication device to initiate an LTM process for migrating to a target cell provided by the target infrastructure equipment, or The LTM candidate configuration information indicates one or more conditions for the communication device to send instructions for the measurement to the infrastructure equipment and / or to execute an LTM procedure for migration to the target cell.

42. A circuit for an infrastructure device of a wireless communication network, the circuit being configured to transmit signals to one or more communication devices and / or receive signals from one or more communication devices via a wireless radio interface provided by the wireless communication network, the circuit comprising: The transmitter circuit is configured to transmit signals. The receiver circuit is configured to receive signals, and The controller circuit is configured to combine with the transmitter circuit and the receiver circuit to perform the following operations: Sending Low-Layer Triggered Mobility (LTM) candidate configuration information to a communication device, wherein the LTM candidate configuration information includes indications of one or more conditions, wherein the one or more conditions are based on measurements to be performed by the communication device as indicated in the LTM candidate configuration information, wherein: The LTM candidate configuration information indicates one or more conditions for the communication device to initiate an LTM process for migrating to a target cell provided by the target infrastructure equipment, or The LTM candidate configuration information indicates one or more conditions for the communication device to send instructions for the measurement to the infrastructure equipment and / or to execute an LTM procedure for migration to the target cell.

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