Preparation steps for LTM

Abstract

Various aspects of this disclosure relate to base stations, processors, and methods for preparation procedures for Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM). In one embodiment, a base station which is a source base station for LTM transmits one or more first request messages via transceivers to one or more candidate base stations for LTM, each for one or more LTM candidate cells belonging to one or more candidate base stations. The base station receives one or more first response messages via transceivers and from one or more candidate base stations for one or more LTM candidate cells, wherein configuration information for each of the one or more LTM candidate cells is included in at least one first response message.

Description

Technical Field

[0001] The present disclosure relates to wireless communication, and more particularly, to a preparation procedure for layer 1 / layer 2 (L1 / L2) trigger-based mobility (LTM), for example, a base station, a processor, and a method for a preparation procedure for LTM between central units (CUs).

Background Art

[0002] A wireless communication system may include one or more network communication devices, such as a base station, sometimes known by an alias such as an evolved NodeB (eNB), a next-generation NodeB (gNB), or other suitable terms. Each network communication device, such as a base station, may support wireless communication for one or more user communication devices, sometimes known by an alias such as a user equipment (UE), or other suitable terms. A wireless communication system may support wireless communication with one or more user communication devices by using resources of the wireless communication system (for example, time resources (for example, symbols, slots, subframes, frames, etc.) or frequency resources (for example, subcarriers, carriers)). Further, the wireless communication system may support wireless communication across various wireless access technologies, including third-generation (3G) wireless access technology, fourth-generation (4G) wireless access technology, 5G wireless access technology, and particularly among other suitable radio access technologies beyond the fifth generation (5G) (for example, sixth generation (6G)).

[0003] 3GPP® has approved a new work item for further enhancing New Radio (NR) mobility, named LTM, to change serving cells via L1 / L2 signaling in order to reduce latency, overhead, and interrupt time. LTM is a PCell (primary cell in a master cell group) or PSCell (primary cell in a secondary cell group) cell switching procedure triggered by a Media Access Control-Control Element (MAC CE) on the network based on L1 measurements. Possible applicable scenarios for LTM include intra-CU distributed unit (DU) LTM, intra-CU inter-DU LTM, and inter-CU LTM. However, for inter-CU LTM, there are still several open challenges in initiating and modifying candidate cell configurations for inter-CU LTM, which need to be considered. [Overview of the project] [Problems that the invention aims to solve]

[0004] This disclosure relates to methods, apparatus, and systems that support preparation procedures for LTM. [Means for solving the problem]

[0005] In a first embodiment of the solution, a base station may comprise a processor and a transceiver coupled to the processor, the base station being a source base station for Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM), the processor being configured to perform an LTM preparation procedure, the LTM preparation procedure comprising: transmitting one or more first request messages via the transceiver and to one or more candidate base stations for LTM, each for one or more LTM candidate cells belonging to one or more candidate base stations, each first request message including first LTM indication information and an identifier for the LTM candidate cell corresponding to the first request message; and receiving one or more first response messages via the transceiver and from one or more candidate base stations for one or more LTM candidate cells, each LTM candidate cell configuration information included in at least one first response message.

[0006] In some implementations of the methods and apparatus described herein, the configuration information of the LTM candidate cell may include at least one of the LTM candidate cell configuration and the reference signal (RS) configuration of the LTM candidate cell.

[0007] In some implementations of the methods and apparatus described herein, the LTM candidate cell configuration and RS configuration of the LTM candidate cell may be included in different first response messages or in the same first response message.

[0008] In some implementations of the methods and apparatus described herein, the RS configuration of the LTM candidate cell may be included in the LTM candidate cell configuration of the LTM candidate cell.

[0009] In some implementations of the methods and apparatus described herein, the LTM preparation procedure may further include assigning an index to one or more LTM candidate cell configurations of one or more LTM candidate cells.

[0010] In some implementations of the methods and apparatus described herein, the LTM preparation procedure may further include sending a second request message via a transceiver to each of one or more candidate base stations, which includes second LTM indication information, an index of one or more LTM candidate cell configurations, and the RS configuration of one or more LTM candidate cells.

[0011] In some implementations of the methods and apparatus described herein, the LTM preparation procedure may further include receiving a second response message as a response to a second request message via a transceiver and from each of one or more candidate base stations.

[0012] In some implementations of the methods and apparatus described herein, the LTM preparation procedure may further include sending a reconfiguration message via a transceiver and to a user equipment (UE) containing one or more LTM candidate cell configurations, indices of one or more LTM candidate cell configurations, and RS configurations of one or more LTM candidate cells.

[0013] In some implementations of the methods and apparatus described herein, the source base station may include a source central unit (CU) and one or more distributed units (DUs), the one or more DUs including a source DU serving a UE, and the index of one or more LTM candidate cell configurations is assigned by the source CU.

[0014] In some implementations of the methods and apparatus described herein, transmitting a reconfiguration message may include transmitting a reconfiguration message, an index of one or more LTM candidate cell configurations, and an RS configuration of one or more LTM candidate cells from a source CU and to a source DU; storing the index of one or more LTM candidate cell configurations and an RS configuration of one or more LTM candidate cells in the source DU; and forwarding the reconfiguration message from the source DU and to the UE.

[0015] In some implementations of the methods and apparatus described herein, the identifier of the LTM candidate cell may include the New Radio (NR) Cell Global Identifier (NCGI) of the LTM candidate cell.

[0016] In some implementations of the methods and apparatus described herein, the first LTM indication information may be an LTM indicator having a first code point or a second code point, the first code point indicating the initiation of preparation of an LTM candidate cell configuration, and the second code point indicating the update of an LTM candidate cell configuration. The second LTM indication information may be an LTM indicator having a third code point, the third code point indicating the storage of an index of one or more LTM candidate cell configurations and the RS configuration of one or more LTM candidate cells.

[0017] In some implementations of the methods and apparatus described herein, the processor may be further configured to perform an LTM preparation procedure when a cancellation message requesting a modification of the LTM candidate cell configuration is received from a candidate base station for LTM, the cancellation message including identifiers of one or more LTM candidate cells to be cancelled.

[0018] In some implementations of the methods and apparatus described herein, the cancellation message may further include a cause value indicating the LTM resource to be modified.

[0019] In some implementations of the methods and apparatus described herein, the processor may be further configured to transmit the identifier of the target LTM candidate cell via a transceiver and to the candidate base station corresponding to the target LTM candidate cell when it decides to perform an LTM to the target LTM candidate cell.

[0020] In a second embodiment of the solution, the base station may comprise a processor and a transceiver coupled to the processor, wherein the base station is a candidate base station for Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM), and the processor is configured to perform an LTM preparation procedure, the LTM preparation procedure comprising: receiving a first request message from the transceiver and from a source base station for LTM for an LTM candidate cell belonging to the candidate base station, the first request message comprising first LTM indication information and an identifier for the LTM candidate cell; preparing configuration information for the LTM candidate cell based on the first request message; and sending at least one first response message from the transceiver and to the source base station, comprising the configuration information for the LTM candidate cell.

[0021] In some implementations of the methods and apparatus described herein, the configuration information may include at least one of the LTM candidate cell configuration and the LTM candidate cell reference signal (RS) configuration.

[0022] In some implementations of the methods and apparatus described herein, the LTM candidate cell configuration and RS configuration of the LTM candidate cell may be included in different first response messages or in the same first response message.

[0023] In some implementations of the methods and apparatus described herein, the RS configuration of the LTM candidate cell may be included in the LTM candidate cell configuration of the LTM candidate cell.

[0024] In some implementations of the methods and apparatus described herein, the identifier of the LTM candidate cell may include the New Radio (NR) Cell Global Identifier (NCGI) of the LTM candidate cell.

[0025] In some implementations of the methods and apparatuses described herein, the LTM preparation procedure may further include receiving, via a transceiver and from a source base station, a second request message including second LTM indication information, an RS configuration of one or more LTM candidate cells identified by the source base station, and an index of one or more LTM candidate cell configurations of one or more LTM candidate cells identified by the source base station, and storing the index of the one or more LTM candidate cell configurations and the RS configuration of the one or more LTM candidate cells.

[0026] In some implementations of the methods and apparatuses described herein, the LTM preparation procedure may further include transmitting, via a transceiver and to the source base station, a second response message as a response to the second request message.

[0027] In some implementations of the methods and apparatuses described herein, the first LTM indication information may be an LTM indicator having a first code point or a second code point, the first code point indicating starting preparation of an LTM candidate cell configuration, and the second code point indicating updating of an LTM candidate cell configuration. The second LTM indication information may be an LTM indicator having a third code point, the third code point indicating storing an index of one or more LTM candidate cell configurations and an RS configuration of one or more LTM candidate cells.

[0028] In some implementations of the methods and apparatuses described herein, a candidate base station may include a candidate central unit (CU) and one or more candidate distributed units (DUs), the first request message and the second request message being received by the candidate CU from the source base station, and the first response message and the second response message being transmitted by the candidate CU to the source base station.

[0029] In some implementations of the methods and apparatuses described herein, preparing configuration information of an LTM candidate cell based on a first request message may include transmitting, from a candidate CU to a candidate DU corresponding to the LTM candidate cell, a first request message including an identifier of the LTM candidate cell, and receiving, at the candidate CU and from the candidate DU, at least one third response message including the configuration information of the LTM candidate cell.

[0030] In some implementations of the methods and apparatuses described herein, storing an index of one or more LTM candidate cell configurations and an RS configuration of one or more LTM candidate cells may include transmitting, from a candidate CU to a candidate DU corresponding to the LTM candidate cell, a fourth request message including an index of one or more LTM candidate cell configurations and an RS configuration of one or more LTM candidate cells, and storing, at the candidate DU, the index of one or more LTM candidate cell configurations and the RS configuration of one or more LTM candidate cells.

[0031] In some implementations of the methods and apparatuses described herein, the processor may be further configured to transmit, via a transceiver and to a source base station, a cancellation message requesting a modification of an LTM candidate cell configuration, the cancellation message including an identifier of one or more LTM candidate cells to be cancelled.

[0032] In some implementations of the methods and apparatuses described herein, the cancellation message may further include a cause value indicating an LTM resource to be changed.

[0033] In some implementations of the methods and apparatuses described herein, the cancellation message may be generated by a candidate CU in response to receiving, from a candidate DU belonging to the candidate CU, a modification message requesting a modification of one or more LTM candidate cell configurations.

[0034] In some implementations of the methods and apparatus described herein, the modification message may include a causal value indicating the LTM resource to be modified.

[0035] In some implementations of the methods and apparatus described herein, the processor may be further configured to receive, via a transceiver and from the source base station, the identifier of the target LTM candidate cell when the source base station decides to perform an LTM to the target LTM candidate cell.

[0036] In a third embodiment of the solution, a processor for wireless communication may include at least one memory and a controller coupled to the at least one memory and configured to cause the processor to perform a Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM) preparation procedure, the procedure comprising: transmitting one or more first request messages via a transceiver and to one or more candidate base stations for LTM, each for one or more LTM candidate cells belonging to one or more candidate base stations, each first request message including first LTM indication information and an identifier for the LTM candidate cell corresponding to the first request message; and receiving one or more first response messages via a transceiver and from one or more candidate base stations for one or more LTM candidate cells, each LTM candidate cell configuration information included in at least one first response message.

[0037] A fourth embodiment of the solution, a method implemented by a source base station for Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM), the method comprising an LTM preparation procedure, the LTM preparation procedure comprising transmitting one or more first request messages via a transceiver and to one or more candidate base stations for LTM, each for one or more LTM candidate cells belonging to one or more candidate base stations, each first request message comprising first LTM indication information and an identifier for an LTM candidate cell corresponding to the first request message, and receiving one or more first response messages via a transceiver and from one or more candidate base stations for one or more LTM candidate cells, each LTM candidate cell configuration information is included in at least one first response message.

[0038] In a fifth embodiment of the solution, a processor for wireless communication comprises at least one memory and a controller coupled to the at least one memory and configured to cause the processor to perform a Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM) preparation procedure, the LTM preparation procedure comprising: receiving a first request message from a source base station for LTM via a transceiver for an LTM candidate cell belonging to a candidate base station, the first request message comprising first LTM indication information and an identifier for an LTM candidate cell; preparing configuration information for an LTM candidate cell based on the first request message; and transmitting at least one first response message via a transceiver to the source base station, comprising the configuration information for an LTM candidate cell.

[0039] A sixth embodiment of the solution, a method implemented by a candidate base station for Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM), the method comprising an LTM preparation procedure, the LTM preparation procedure comprising: receiving a first request message from a source base station for LTM via a transceiver for an LTM candidate cell belonging to the candidate base station, the first request message comprising first LTM indication information and an identifier for an LTM candidate cell; preparing configuration information for the LTM candidate cell based on the first request message; and sending at least one first response message via a transceiver to the source base station, comprising the configuration information for the LTM candidate cell.

[0040] Please understand that this abstract is not intended to identify any key or essential features of the embodiments of the Disclosure, nor is it intended to be used to limit the scope of the Disclosure. Other features of the Disclosure will be readily apparent from the following description. [Brief explanation of the drawing]

[0041] [Figure 1] This figure shows an example of a wireless communication system that supports preparation procedures for LTM according to aspects of this disclosure. [Figure 2A] This figure shows exemplary scenarios of LTM associated with aspects of this disclosure. [Figure 2B] This figure shows exemplary scenarios of LTM associated with aspects of this disclosure. [Figure 2C] This figure shows exemplary scenarios of LTM associated with aspects of this disclosure. [Figure 3] This figure shows a signaling procedure for a preparation procedure for LTM according to an aspect of the present disclosure. [Figure 4] This figure shows an example of a signaling procedure for a preparation procedure for LTM according to an aspect of this disclosure. [Figure 5] This figure shows another example of a signaling procedure for a preparation procedure for LTM according to an aspect of the present disclosure. [Figure 6] This figure shows an example of a device that supports preparation procedures for LTM according to aspects of this disclosure. [Figure 7] This figure shows an example of a device that supports preparation procedures for LTM according to aspects of this disclosure. [Figure 8] This figure shows an example of a processor that supports preparation procedures for LTM according to an aspect of this disclosure. [Figure 9] This figure shows an example of a processor that supports preparation procedures for LTM according to an aspect of this disclosure. [Figure 10] This is a flowchart of a method for supporting preparation procedures for LTM according to the aspects of this disclosure. [Figure 11] This is a flowchart of a method for supporting preparation procedures for LTM according to the aspects of this disclosure. [Modes for carrying out the invention]

[0042] The principles of this disclosure are described here with reference to several embodiments. These embodiments are described for illustrative purposes only and should be understood as helping those skilled in the art to understand and implement this disclosure, without implying any limitation on the scope of this disclosure. The disclosures described herein may be implemented in various ways other than those described below.

[0043] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art of the field to which this disclosure belongs.

[0044] References in this disclosure to “one embodiment,” “exemplary embodiment,” “embodiment,” and “some embodiments” indicate that the embodiments described may include certain features, structures, or characteristics, but not all embodiments are required to include such features, structures, or characteristics. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when certain features, structures, or characteristics are described in relation to a particular embodiment, it is stated that this is within the scope of what a person skilled in the art would know to affect such features, structures, or characteristics in relation to other embodiments, whether explicitly stated or not.

[0045] Terms such as "first" and "second" may be used herein to describe various elements, but it should be understood that these elements should not be limited by these terms. These terms are used merely to distinguish one element from another. For example, without departing from the scope of the embodiment, the first element may be called the second element, and similarly, the second element may be called the first element. The term "and / or" as used herein includes any combination of one or more of the listed terms.

[0046] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the exemplary embodiments. The singular forms “a,” “an,” and “the” as used herein also include the plural form unless the context otherwise explicitly indicates. It should be further understood that, as used herein, the terms “comprises,” “comprising,” “has,” “having,” “includes,” and / or “including” specify the existence of the described function, element, and / or component, but do not exclude the existence or addition of one or more other functions, elements, components, and / or combinations thereof.

[0047] As used herein, the term “communication network” refers to any network conforming to any appropriate communication standard, such as 5G New Radio (NR), Long-Term Evolution (LTE), LTE Advanced (LTE-A), Broadband Code Division Multiple Access (WCDMA®), High-Speed ​​Packet Access (HSPA), and Narrowband Internet of Things (NB-IoT). Furthermore, communication between terminal devices and network devices within a communication network may be carried out according to any appropriate generation communication protocol, including but not limited to first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols, and / or any other protocols currently known or to be developed in the future. Embodiments of this disclosure may be applied to various communication systems. Given the rapid development in communications, there may be future communication technologies and systems to which this disclosure may be embodied. It should not be considered that the scope of this disclosure is limited to the systems described above.

[0048] As used herein, the term “network device” generally refers to a node in a communication network from which a terminal device can access the communication network and receive services. Depending on the terminology and technology applied, a network device may refer to a base station (BS) or access point (AP), such as a Node B (NodeB or NB), a Radio Access Network (RAN) node, an Advanced Node B (eNodeB or eNB), an NR NB (also known as a gNB), a Remote Radio Unit (RRU), a Radio Header (RH), an Infrastructure Device for V2X (vehicle-to-vehicle-to-infrastructure) communication, a Transmit Receive Point (TRP), a Receive Point (RP), a Remote Radio Head (RRH), a repeater, an Access Backhaul Integration (IAB) node, a low-power node such as a femtoBS or picoBS, and so on.

[0049] As used herein, the term “terminal device” generally refers to any terminal device that may be capable of wireless communication. For the purposes of this document, terminal devices may also be called communication devices, user equipment (UE), end-user devices, subscriber stations (SS), unmanned aerial vehicles (UAVs), portable subscriber stations, mobile stations (MS), or access terminals (AT). Terminal devices may include, but are not limited to, mobile phones, cellular phones, smartphones, voice over IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback devices, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop mounted devices (LMEs), Universal Serial Bus (USB) dongles, smart devices, wireless customer premises equipment (CPEs), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices (e.g., remote surgery devices), industrial devices (e.g., robots and / or other wireless devices operating in an industrial and / or automated processing chain context), consumer electronic devices, and devices operating in commercial and / or industrial wireless networks. In the following description, the terms “terminal device,” “communication device,” “terminal,” “user equipment,” and “UE” may be used interchangeably.

[0050] As mentioned above, when a UE moves from one cell to another, a serving cell change must be performed at some point. In legacy systems, serving cell changes are performed by explicit Radio Resource Control (RRC) reconfiguration signaling to trigger synchronization of the target cell based on L3 measurement reports. This results in longer latency, greater overhead, and longer interrupt times than beam-level mobility.

[0051] In the 3rd Generation Partnership Project (3GPP®), a new work item for further NR mobility enhancements, named LTM, has been approved to modify serving cells via L1 / L2 signaling in order to reduce latency, overhead, and interrupt time during cell switching.

[0052] Figures 2A to 2C illustrate exemplary scenarios of LTMs associated with aspects of this disclosure. Figure 2A shows a scenario for intra-CU intra-DU LTM, Figure 3B shows a scenario for intra-CU inter-DU LTM, and Figure 3C shows a scenario for inter-CU inter-DU LTM.

[0053] As shown in Figure 2A, in the scenario for LTM within a CU and within a DU, the UE moves between different cells within the same DU. As shown in Figure 2B, in the scenario for LTM between CUs and between DUs, the UE moves between different cells within the same CU but belonging to different DUs. As shown in Figure 2C, in the scenario for LTM between CUs, the UE moves between different cells belonging to different DUs, where the different DUs belong to different CUs.

[0054] In LTM, two concepts are proposed: LTM candidate cells and LTM candidate cell configurations. An LTM candidate cell refers to a cell used for LTM, excluding the serving cell in the source DU. In some cases, the serving cell in the source DU may be an LTM candidate cell in the case of a subsequent LTM. There may be multiple LTM candidate cells prepared for a UE, and these LTM candidate cells may belong to the same DU or different candidate DUs (including different candidate DUs belonging to different candidate CUs). An LTM candidate cell configuration refers to the configuration associated with an LTM candidate cell. Each LTM candidate cell configuration can be identified by an index called an LTM candidate cell configuration index, LTM candidate configuration index, or other name. For example, the LTM candidate cell configuration index may be LTM-CandidateId, which is used to identify an LTM candidate cell configuration.

[0055] When considering inter-CU LTM, several issues need to be considered, as follows: The first issue is that in the case of inter-CU LTM (for example, when a UE moves from a source CU to a candidate CU), the LTM candidate cell may belong to a different CU. It is unclear how to initiate and modify the inter-CU LTM candidate cell configuration.

[0056] The second problem is that while an index of LTM candidate cell configurations is required for LTM, it is unclear how to adjust the index related to the inter-CU LTM candidate cell configuration to support L1 measurement reports. The third problem is that when performing inter-CU LTM, the UE moves between different cells belonging to different DUs, and if these DUs belong to different CUs, the UE must avoid early data forwards with unnecessary buffering of data across multiple candidate DUs, and slow data forwards with high interruption times. It is unclear how to perform timely data forwards to candidate DUs. Therefore, a solution is needed to address the above issues in order to support inter-CU LTM.

[0057] This disclosure proposes a solution to support preparation procedures for LTM, for example, for CU-to-LTM. In this solution, the source CU can interact with candidate CUs and manage (e.g., retrieve, modify, or update) the LTM candidate cell configuration and the RS configuration of the LTM candidate cell. By implementing the exemplary embodiments of this disclosure, the preparation procedures for LTM can be extended to CU-to-LTM.

[0058] The aspects of this disclosure are described in the context of wireless communication systems.

[0059] Figure 1 shows an example of a wireless communication system 100 supporting preparation procedures for LTM according to an aspect of this disclosure. The wireless communication system 100 may include one or more network entities 102 (also called network equipment (NEs)), one or more UEs 104, a core network 106, and a packet data network 108. The wireless communication system 100 may support various radio access technologies. In some implementations, the wireless communication system 100 may be a 4G network, such as an LTE network or an LTE Advanced (LTE-A) network. In some other implementations, the wireless communication system 100 may be a 5G network, such as an NR network. In other implementations, the wireless communication system 100 may be a combination of 4G and 5G networks, or other suitable radio access technologies, including IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), and IEEE 802.20. The wireless communication system 100 may support radio access technologies beyond 5G. Furthermore, the wireless communication system 100 may support technologies such as time-division multiple access (TDMA), frequency-division multiple access (FDMA), or code-division multiple access (CDMA).

[0060] One or more network entities 102 may be distributed across a geographical area to form a wireless communication system 100. One or more of the network entities 102 described herein may be a network node, base station, network element, radio access network (RAN), transceiver base station, access point, NodeB, eNodeB (eNB), next-generation NodeB (gNB), or other appropriate terms, or may include them, or may be referred to as such. The network entities 102 and UE 104 may communicate via a communication link 110, which may be wireless or wired. For example, the network entities 102 and UE 104 may perform wireless communication via a Uu interface (e.g., receiving and transmitting signaling).

[0061] Network entity 102 may provide a geographic coverage area 112 that network entity 102 can support for services (e.g., voice, video, packet data, messaging, broadcast, etc.) for one or more UEs 104 within that geographic coverage area 112. For example, network entity 102 and UE 104 may support wireless communication of signals associated with services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or more radio access technologies. In some implementations, network entity 102 may be mobile and, for example, a satellite associated with a non-terrestrial network. In some implementations, different geographic coverage areas 112 associated with the same or different radio access technologies may overlap, or different geographic coverage areas 112 may be associated with different network entities 102. The information and signals described herein may be represented using any of a wide variety of technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or optical particles, or any combination thereof.

[0062] One or more UEs 104 may be distributed across the geographical area of ​​the wireless communication system 100. The UEs 104 may include, or be referred to as, mobile devices, wireless devices, remote devices, remote units, handheld devices, or subscriber devices, or any other appropriate term. In some implementations, the UEs 104 may be referred to as units, stations, terminals, or clients, among other examples. Additionally or alternatively, the UEs 104 may be referred to as Internet of Things (IoT) devices, any Internet of Things (IoE) devices, or machine-type communications (MTC) devices, among other examples. In some implementations, the UEs 104 may be stationary within the wireless communication system 100. In some implementations, the UEs 104 may be mobile within the wireless communication system 100.

[0063] One or more UE104s may be devices of different forms or with different capabilities. Several examples of UE104s are shown in Figure 1. UE104s may be capable of communicating with various types of devices, such as network entities 102, other UE104s, or network equipment (e.g., core network 106, packet data network 108, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment), as shown in Figure 1. Additionally or alternatively, UE104s may support communication with other network entities 102 or UE104s, which may act as relays in the wireless communication system 100.

[0064] UE104 may also support direct wireless communication with other UE104s via communication link 114. For example, UE104 may support direct wireless communication with another UE104 via a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-infrastructure (V2X) deployments, or cellular V2X deployments, communication link 114 may be called a side link. For example, UE104 may support direct wireless communication with another UE104 via the PC5 interface.

[0065] A network entity 102 may support communication with the core network 106, or with another network entity 102, or both. For example, a network entity 102 may interface with the core network 106 through one or more backhaul links 116 (e.g., via S1, N2, or another network interface). Network entities 102 may communicate with each other through the backhaul links 116 (e.g., via X2, Xn, or another network interface). In some implementations, network entities 102 may communicate with each other directly (e.g., between network entities 102). In some other implementations, network entities 102 may communicate with each other or indirectly (e.g., via the core network 106). In some implementations, one or more network entities 102 may include sub-components such as access network entities, which may be examples of access node controllers (ANCs). An ANC may communicate with one or more UEs 104 through one or more other access network transmitting entities, which may be called radio heads, smart radio heads, or transmit / receive points (TRPs).

[0066] In some implementations, the network entity 102 may consist of a decoupled architecture, which may be configured to use a physically or logically distributed protocol stack between two or more network entities 102, such as an Access Backhaul Integration (IAB) network, an Open Radio Access Network (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a Virtualized RAN (vRAN) (e.g., a Cloud RAN (C-RAN)). For example, the network entity 102 may include one or more of the following, or any combination thereof: CUs, DUs, Radio Units (RUs), RAN Intelligent Controllers (RICs) (e.g., Near Real-Time RICs (Near RT RICs), Non-Real-Time RICs (Non-RT RICs)), Service Management and Orchestration (SMO) systems.

[0067] RU may also be called a radio head, smart radio head, remote radio head (RRH), remote radio unit (RRU), or transmit / receive point (TRP). One or more components of network entity 102 in a separated RAN architecture may be co-located, or one or more components of network entity 102 may be located in distributed locations (e.g., separate physical locations). In some implementations, one or more network entities 102 in a separated RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), virtual RU (VRU)).

[0068] The functional division between CUs, DUs, and RUs may be flexible and may support different functionalities depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, radio frequency functions, and any combination thereof) are performed in the CU, DU, or RU. For example, a functional division of the protocol stack may be used between the CU and DU so that the CU may support one or more layers of the protocol stack and the DU may support one or more different layers of the protocol stack. In some implementations, the CU may host higher protocol layer (e.g., Layer 3 (L3), Layer 2 (L2)) functionalities and signaling (e.g., Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), Packet Data Convergence Protocol (PDCP)). The CU may be connected to one or more DUs or RUs, each of which may host lower protocol layers such as Layer 1 (L1) (e.g., physical (PHY) layer) or L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, each of which may be at least partially controlled by the CU160.

[0069] As an addition or alternative, a functional decomposition of the protocol stack may be used between the DU and RU so that the DU can support one or more layers of the protocol stack and the RU can support one or more different layers of the protocol stack. The DU may support one or more different cells (for example, through one or more RUs). In some implementations, the functional decomposition between the CU and the DU, or between the DU and the RU, may be within the protocol layer (for example, some functions for the protocol layer may be performed by one of the CU, DU, or RU, and other functions of the protocol layer may be performed by one of the different CU, DU, or RU).

[0070] A CU may be further functionally divided into CU control plane (CU-CP) and CU user plane (CU-UP) functions. A CU may be connected to one or more DUs via midhaul communication links (e.g., F1, F1-c, F1-u), and a DU may be connected to one or more RUs via fronthaul communication links (e.g., open fronthaul (FH) interfaces). In some implementations, the midhaul or fronthaul communication links may be implemented according to interfaces (e.g., channels) between layers of protocol stacks supported by each network entity 102 communicating via such communication links.

[0071] The core network 106 can support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The core network 106 may be an advanced packet core (EPC) or a 5G core (5GC), which may include control plane entities that manage access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)), as well as user plane entities that route packets or interconnect to external networks (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entities may manage non-access layer (NAS) functions such as mobility, authentication, and bearer management (e.g., data bearers, signal bearers, etc.) for one or more UEs 104 served by one or more network entities 102 associated with the core network 106.

[0072] The core network 106 may communicate with the packet data network 108 via one or more backhaul links 116 (for example, via S1, N2, or another network interface). The packet data network 108 may include an application server 118. In some implementations, one or more UEs 104 may communicate with the application server 118. The UEs 104 may establish a session with the core network 106 (for example, a protocol data unit (PDU) session) via a network entity 102. The core network 106 may use the established session (for example, an established PDU session) to route traffic (for example, control information, data, etc.) between the UEs 104 and the application server 118. The PDU session may be an example of a logical connection between the UEs 104 and the core network 106 (for example, one or more network functions of the core network 106).

[0073] In the wireless communication system 100, the network entities 102 and UE104 can use the resources of the wireless communication system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, etc.) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communication). In some implementations, the network entities 102 and UE104 may support different resource structures. For example, the network entities 102 and UE104 may support different frame structures. In some implementations, for example in 4G, the network entities 102 and UE104 may support a single frame structure. In some other implementations, for example in 5G, and in other suitable radio access technologies, the network entities 102 and UE104 may support various frame structures (i.e., multiple frame structures). The network entities 102 and UE104 may support various frame structures based on one or more numerologies.

[0074] One or more numerologies may be supported in the wireless communication system 100, and the numerologies may include subcarrier intervals and cyclic prefixes. A first numerology (e.g., μ=0) may be associated with a first subcarrier interval (e.g., 15 kHz) and a typical cyclic prefix. In some implementations, the first numerology (e.g., μ=0) associated with the first subcarrier interval (e.g., 15 kHz) may use one slot per subframe. A second numerology (e.g., μ=1) may be associated with a second subcarrier interval (e.g., 30 kHz) and a typical cyclic prefix. A third numerology (e.g., μ=2) may be associated with a third subcarrier interval (e.g., 60 kHz) and a typical cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., μ=3) may be associated with a fourth subcarrier interval (e.g., 120 kHz) and a typical cyclic prefix. A fifth numerology (e.g., μ=4) may be associated with a fifth subcarrier interval (e.g., 240 kHz) and a typical cyclic prefix.

[0075] The time intervals of resources (e.g., communication resources) may be organized according to frames (also called wireless frames). Each frame may have a duration, for example, 10 milliseconds (ms). In some implementations, each frame may contain multiple subframes. For example, each frame may contain 10 subframes, each subframe may have a duration, for example, 1 ms. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

[0076] As an addition or alternative, the time intervals of resources (e.g., communication resources) may be organized according to slots. For example, a subframe may contain a certain number (e.g., a quantity) of slots. The number of slots in each subframe may depend on one or more numerologies supported in the wireless communication system 100. For example, the first, second, third, fourth, and fifth numerologies (i.e., μ=0, μ=1, μ=2, μ=3, μ=4) associated with the respective subcarrier intervals of 15kHz, 30kHz, 60kHz, 120kHz, and 240kHz may use one slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and sixteen slots per subframe, respectively. Each slot may contain a certain number (e.g., a quantity) of symbols (e.g., OFDM symbols). In some implementations, the number (e.g., a quantity) of slots for a subframe may depend on the numerology. For a standard cyclic prefix, a slot may contain 14 symbols. For an extended cyclic prefix (e.g., applicable to a 60 kHz subcarrier interval), a slot may contain 12 symbols. The relationships between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for standard and extended cyclic prefixes may depend on the numerology. It should be understood that references to a first numerology (e.g., μ=0) associated with a first subcarrier interval (e.g., 15 kHz) may be used interchangeably between subframes and slots.

[0077] In the wireless communication system 100, the electromagnetic (EM) spectrum can be divided into various classes, frequency bands, frequency channels, etc., based on frequency or wavelength. For example, the wireless communication system 100 may support one or more operating frequency bands, such as frequency range designations FR1 (410 MHz to 7.125 GHz), FR2 (24.25 GHz to 52.6 GHz), FR3 (7.125 GHz to 24.25 GHz), FR4 (52.6 GHz to 114.25 GHz), FR4a or FR4-1 (52.6 GHz to 71 GHz), and FR5 (114.25 GHz to 300 GHz). In some implementations, network entities 102 and UE 104 may conduct wireless communication over one or more of these operating frequency bands. In some implementations, FR1 may be used by network entities 102 and UE 104, in particular, among other equipment or devices for cellular communication traffic (e.g., control information, data). In some implementations, FR2 can be used by network entities 102 and UE104, in particular, among other equipment or devices for short-range, high-data-rate capabilities.

[0078] FR1 may be associated with one or more numerologies (e.g., at least three). For example, FR1 may be associated with a first numerology including a 15 kHz subcarrier interval (e.g., μ=0), a second numerology including a 30 kHz subcarrier interval (e.g., μ=1), and a third numerology including a 60 kHz subcarrier interval (e.g., μ=2). FR2 may be associated with one or more numerologies (e.g., at least two). For example, FR2 may be associated with a third numerology including a 60 kHz subcarrier interval (e.g., μ=2), and a fourth numerology including a 120 kHz subcarrier interval (e.g., μ=3).

[0079] Figure 3 shows an exemplary signaling procedure 300 for a subsequent LTM preparation procedure (i.e., an LTM preparation procedure) according to aspects of the present disclosure. The source base station 102-1 and candidate base stations 102-2 to 102-N shown in Figure 3 are base stations for (i.e., supporting) an LTM, and may be, for example, a gNB or other types of base stations applicable for an LTM. Source base station 102-1 may include a source central unit (CU) and one or more distributed units (DUs), one or more of which may include a source DU serving a UE. Furthermore, each of the candidate base stations 102-2 to 102-N may include a candidate central unit (CU) and one or more candidate distributed units (DUs). Hereafter, for ease of understanding, the interaction between source base station 102-1 and candidate base station 102-2 is described as an example, but the interaction between source base station 102-1 and other candidate base stations is similar and is therefore omitted for brevity.

[0080] As shown in Figure 3, in step 302, source base station 102-1 sends one or more first request messages to one or more candidate base stations 102-2 to 102-N for LTM, each for one or more LTM candidate cells belonging to one or more candidate base stations 102-2 to 102-N, and each first request message includes first LTM indication information and an identifier of the LTM candidate cell corresponding to the first request message. That is, for example, if source base station 102-1 determines that it has identified eight LTM candidate cells and obtained their configuration information, source base station 102-1 may generate eight first request messages, each corresponding to one of the eight LTM candidate cells, and then send these first request messages to one or more candidate base stations to which the eight LTM candidate cells belong.

[0081] In some exemplary embodiments, the identifier of an LTM candidate cell may include the New Radio (NR) Cell Global Identifier (NCGI) of the LTM candidate cell.

[0082] In some exemplary embodiments, the first LTM indication information may be an LTM indicator that indicates initiating the preparation of an LTM candidate cell configuration (hereinafter referred to as LTM initiation) or updating an LTM candidate cell configuration (hereinafter referred to as LTM update or LTM replacement). For example, the first LTM indication information may be an LTM indicator having a first code point or a second code point, the first code point indicating initiating the preparation of an LTM candidate cell configuration, and the second code point indicating an update of an LTM candidate cell configuration. That is, when source base station 102-1 wants to initiate an LTM preparation procedure or update or replace existing configuration information of a previously acquired LTM candidate cell, source base station 102-1 may perform step 302 and use the first indication information to indicate the purpose of the first request message.

[0083] Each of the one or more candidate base stations 102-2 to 102-N may, in step 302, receive a first request message from source base station 102-1 for an LTM candidate cell belonging to the candidate base station itself, which was transmitted by source base station 102-1. Figure 3 shows that each candidate base station receives one first request message, but is not limited to this disclosure, and a candidate base station may receive more first request messages. For example, if two LTM candidate cells that belong to candidate base station 102-2 have identifiers included in the first request message transmitted by source base station, candidate base station 102-2 may receive two first request messages, each message corresponding to one of the two LTM candidate cells.

[0084] After the first request message is received, in step 304, each candidate base station may prepare configuration information for an LTM candidate cell based on the received first request message. For example, a candidate base station may prepare configuration information for an LTM candidate cell that includes an identifier in the received first request message. Then, in step 306, each candidate base station may transmit the prepared configuration information for an LTM candidate cell to the source base station 102-1. For example, each candidate base station may transmit at least one first response message containing the configuration information for an LTM candidate cell to the source base station 102-1. In some exemplary embodiments, a candidate base station may transmit a maximum number of LTM preparations to the source base station 102-1, which indicates the maximum number of LTM candidate cells prepared in parallel for the UE at the candidate base station.

[0085] In other words, in step 306, source base station 102-1 may receive one or more first response messages from one or more candidate base stations 102-2 to 102-N for one or more LTM candidate cells. In some exemplary embodiments, the configuration information of each of the one or more LTM candidate cells may be included in at least one first response message. That is, for each LTM candidate cell, its configuration information may be transmitted to source base station 102-1 by at least one message.

[0086] In some exemplary embodiments, the configuration information of an LTM candidate cell may include at least one of the LTM candidate cell configuration and the reference signal (RS) configuration of the LTM candidate cell. For example, the LTM candidate cell configuration and RS configuration of an LTM candidate cell may be included in the same first response message and transmitted together to the source base station 102-1, for example, the RS configuration of an LTM candidate cell may be included in the LTM candidate cell configuration of the LTM candidate cell and then transmitted to the source base station 102-1 by one first response message, or the RS configuration of an LTM candidate cell and the LTM candidate cell configuration of an LTM candidate cell may be separate from each other in a first response message and then transmitted together to the source base station 102-1 by the first response message. As another example, the LTM candidate cell configuration and RS configuration of an LTM candidate cell may be included in different first response messages and then transmitted separately to the source base station 102-1. Alternatively, one of the LTM candidate cell configuration and RS configuration of the LTM candidate cell may be transmitted to the source base station 102-1 in a first response message, as requested by the source base station 102-1 (for example, based on additional indication from the source base station 102-1).

[0087] In some exemplary embodiments, the first request message includes first LTM indication information and identifiers for the LTM candidate cells. That is, for example, if source base station 102-1 determines that it has identified four LTM candidate cells and needs to obtain their configuration information, source base station 102-1 may generate a first request message corresponding to the four LTM candidate cells and then transmit the first request message to one candidate base station to which the four LTM candidate cells belong. Thus, the first response message includes the configuration information for the four LTM candidate cells.

[0088] In some exemplary embodiments, when the configuration information for LTM candidate cells is prepared at each candidate base station in step 304, taking candidate base station 102-2 as an example, the candidate CU of candidate base station 102-2 may receive a first request message and then generate a third request message containing the identifier of the LTM candidate cell included in the first request message, and send it to the candidate DU corresponding to the LTM candidate cell identified by the identifier. Based on the identifier, the candidate DU may obtain the configuration information for the LTM candidate cell and send the same to the candidate CU. The candidate CU may then receive the configuration information for the LTM candidate cell from the candidate DU. For example, the candidate CU may receive at least one third response message containing the configuration information for the LTM candidate cell from the candidate DU. That is, the LTM candidate cell configuration and RS configuration of an LTM candidate cell may be included in the same third response message and sent together to the candidate CU. For example, the RS configuration of an LTM candidate cell may be included in the LTM candidate cell configuration of an LTM candidate cell and then sent to the candidate CU by a single third response message, or the RS configuration of an LTM candidate cell and the LTM candidate cell configuration of an LTM candidate cell may be separate from each other in a third response message and then sent together to the candidate CU by a third response message. As another example, the LTM candidate cell configuration and RS configuration of an LTM candidate cell may be included in different third response messages and then sent separately to the candidate CU. Or, only one of the LTM candidate cell configuration and RS configuration of an LTM candidate cell may be sent to the candidate CU by a third response message as required by the source base station (for example, based on additional indication from the source base station). A more detailed explanation of the configuration information is given below with reference to Figure 4.

[0089] In some exemplary embodiments, the third request message includes multiple identifiers of LTM candidate cells. That is, for example, if a candidate CU determines that it has identified four LTM candidate cells and wants to obtain their configuration information, the candidate CU may generate a third request message corresponding to the four LTM candidate cells and then send the third request message to a candidate DU to which the four LTM candidate cells belong. Thus, the third response message includes the configuration information of the four LTM candidate cells.

[0090] In some exemplary embodiments, after step 306, the source base station 102-1 may obtain one or more LTM candidate cell configurations and / or RS configurations of one or more LTM candidate cells. The source base station 102-1 (for example, the source CU of the source base station 102-1) may then assign an index to one or more LTM candidate cell configurations of one or more LTM candidate cells.

[0091] In some exemplary embodiments, source base station 102-1 may send a second request message to each of the one or more candidate base stations 102-2 to 102-N, which includes second LTM indication information, an index of one or more LTM candidate cell configurations, and the RS configuration of one or more LTM candidate cells (if any). That is, for one of the one or more candidate base stations 102-2 to 102-N, that candidate base station (for example, its candidate CU) may receive a second request message which includes second LTM indication information, the RS configuration of one or more LTM candidate cells identified by the source base station, and an index of one or more LTM candidate cell configurations of one or more LTM candidate cells identified by the source base station.

[0092] In some exemplary embodiments, each candidate base station (for example, a candidate CU of a candidate base station) may send a second response message to the source base station 102-1 in response to the second request message.

[0093] In some exemplary embodiments, the second LTM indication information may also be the same LTM indicator as the first LTM indication information (or be indicated by it). For example, the second LTM indication information may be an LTM indicator having a third code point (or be indicated by it), the third code point indicating that it stores an index of one or more LTM candidate cell configurations and the RS configuration of one or more LTM candidate cells. That is, the LTM indicator may be used to represent first and second LTM indication information having different code points.

[0094] In some exemplary embodiments, after the second request message is received by a candidate base station (for example, a candidate CU of the candidate base station), the candidate base station may store the index of one or more LTM candidate cell configurations and the RS configuration of one or more LTM candidate cells.

[0095] In some exemplary embodiments, when a candidate base station stores the index of one or more LTM candidate cell configurations and the RS configuration of one or more LTM candidate cells, the candidate CU of the candidate base station may send a fourth request message to the candidate DU corresponding to the LTM candidate cell identified by the source base station, which includes the index of one or more LTM candidate cell configurations and the RS configuration of one or more LTM candidate cells. The candidate DU of the candidate base station may then store the index of one or more LTM candidate cell configurations and the RS configuration of one or more LTM candidate cells, and then send a fourth response message to the candidate CU.

[0096] In some exemplary embodiments, the source base station 102-1 may send a reconfiguration message to the user equipment (UE) 104, which includes one or more LTM candidate cell configurations, indices of one or more LTM candidate cell configurations, and RS configurations of one or more LTM candidate cells.

[0097] In some exemplary embodiments, the source CU of the source base station 102-1 may send a reconfiguration message, an index of one or more LTM candidate cell configurations, and the RS configuration of one or more LTM candidate cells to the source DU serving the UE. The source DU can store the index of one or more LTM candidate cell configurations and the RS configuration of one or more LTM candidate cells and forward the reconfiguration message to the UE 104.

[0098] After the above steps and various processes, UE104, source base station (including source CU and source DU) 102-1, and each candidate base station (including candidate CU and candidate DU corresponding to the LTM candidate cell) identified by source base station 102-1 will know the configuration information of these LTM candidate cells, thereby completing the preparation procedure for LTM.

[0099] In some exemplary embodiments, after the preparation steps for LTM are completed, the source base station 102-1 may receive an L1 measurement report from the UE 104 and decide whether to perform LTM to the target LTM candidate cell. If the source base station 102-1 decides to perform LTM to the target LTM candidate cell, it may transmit the identifier of the target LTM candidate cell to the candidate base station corresponding to the target LTM candidate cell. The source base station 102-1 may also transmit the index of the LTM candidate cell configuration of the target LTM candidate cell to the UE 104.

[0100] In some exemplary embodiments, if the source base station 102-1 receives a cancellation message from a candidate base station for LTM requesting a modification of the LTM candidate cell configuration, the source base station 102-1 may perform (or initiate) the LTM preparation procedure 300 again.

[0101] In some exemplary embodiments, the cancellation message may include identifiers of one or more LTM candidate cells to be cancelled. Furthermore, the cancellation message may further include a cause value indicating the LTM resource to be modified.

[0102] In some exemplary embodiments, a cancellation message is generated by a candidate CU of a candidate base station in response to receiving a correction message from a candidate DU of the candidate base station requesting a modification to one or more LTM candidate cell configurations. The correction message may include a cause value indicating the LTM resource to be modified.

[0103] In other words, if a candidate base station that has the configuration information of an LTM candidate cell identified by a source base station notices that the configuration information of the LTM candidate cell has been modified, this candidate base station may cause the source base station 102-1 to perform the LTM preparation procedure 300 again by sending a cancellation message, thereby realizing the update of the LTM candidate cell configuration initiated by the candidate base station.

[0104] A more detailed explanation of these steps is provided below, with reference to Figures 4 and 5.

[0105] Figure 4 shows an example of a signaling procedure 400 for a preparation procedure for LTM according to an aspect of the present disclosure. Figure 4 relates to the initiation or source CU initiation modification of an interCU LTM candidate cell configuration.

[0106] As shown in Figure 4, the signaling procedure 400 involves UE 104, source base station 102-1, and candidate base station 102-2. Here, both source base station 102-1 and candidate base station 102-2 may be base stations for (i.e., supporting LTM), and may be, for example, gNB, or other types of base stations applicable for LTM. Furthermore, although only candidate base station 102-2 is shown in Figure 4, the signaling procedure between source base station 102-1 and candidate base station 102-2 is applicable to the signaling procedure between source base station 102-1 and other candidate base stations.

[0107] In some exemplary embodiments, source base station 102-1 may include source CU 102-10 and one or more DUs, one or more of which include source DU 102-11 serving UE 104. Candidate base station 102-2 may include candidate CU 102-20 and one or more candidate DUs. Here, only candidate DU 102-21 of the one or more candidate DUs is shown in Figure 4 for brevity.

[0108] In some exemplary embodiments, in step 402, source CU102-10 may send a handover request message (corresponding to the first request message in Figure 3) to candidate CU102-20. The handover request message may include an identifier for the LTM candidate cell (e.g., the NCGI of the LTM candidate cell) and an LTM indicator indicating that the handover request is for LTM. In one example, the LTM indicator may include a first code point that indicates a request for LTM activation, that is, candidate CU102-20 should activate the preparation of the LTM candidate cell configuration for the LTM candidate cell. For example, the first code point is "LTM activation". In another example, the LTM indicator may further include an additional indicator that indicates a request for LTM candidate cell configuration, or RS configuration, or both LTM candidate cell configuration and RS configuration. In yet another example, the LTM indicator may include a second code point that indicates a request for updating the LTM candidate cell configuration. In other words, candidate CU102-20 should delete the existing prepared LTM candidate cell configuration identified by the NCGI of the LTM candidate cell, and then candidate CU102-20 should initiate the preparation of a new LTM candidate cell configuration for the LTM candidate cell. For example, the second code point may be "LTM update" or "LTM replacement". In another example, the handover request message may contain identifiers for multiple LTM candidate cells. In yet another example, source CU102-10 may use a message other than the handover request message sent to candidate CU102-20.

[0109] In some exemplary embodiments, in step 404, candidate CU102-20 may send a UE context setup request message (corresponding to the third request message in Figure 3) containing the NCGI of the LTM candidate cell to candidate DU102-21.

[0110] In some exemplary embodiments, in step 406, candidate DU102-21 may respond to candidate CU102-20 with a UE context setup response message (corresponding to the third response message in Figure 3) that includes the LTM candidate cell configuration and / or RS configuration for the LTM candidate cell. The RS configuration may include a group of one or more RS resources for the LTM candidate cell. The RS resources may be, for example, a non-zero power channel state information reference signal (NZP-CSI-RS) resource, a channel state information synchronization signal / physical broadcast channel block (CSI-SSB) resource, and / or a channel state information interference management (CSI-IM) resource. In other words, candidate CU102-20 and candidate DU102-21 may prepare the LTM candidate cell configuration and / or RS configuration for the LTM candidate cell requested by using the NCGI of the LTM candidate cell in steps 404 and 406.

[0111] In some exemplary embodiments, in step 408, candidate CU102-20 may send a handover request acknowledgment message (corresponding to the first response message in Figure 3) to source CU102-10. The handover request acknowledgment message may include the prepared LTM candidate cell configuration and / or RS configuration of the requested LTM candidate cell. In one example, the RS configuration may be included in the LTM candidate cell configuration.

[0112] In some exemplary embodiments, in step 410, source CU102-10 may assign an index to each LTM candidate cell configuration. The index may be used to identify the LTM candidate cell configuration. For example, the index may be LTM-CandidateId, which has a value between 0 and 7.

[0113] In some exemplary embodiments, in step 412, source CU102-10 may send a DL RRC message transfer message to source DU102-11. The DL RRC message transfer message may include an RRCReconfiguration message, which includes the LTM candidate cell configuration of one or more LTM candidate cells, an index of the LTM candidate cell configuration, and the RS configuration of one or more LTM candidate cells, as received by source CU102-10. Furthermore, the DL RRC message transfer message may further include the index and RS configuration of one or more LTM candidate cells, which are stored by source DU102-11. In some exemplary embodiments, source CU102-10 may use another message (for example, a UE context modification request message) instead of a DL RRC message transfer message to send the above information to source DU102-11.

[0114] In some exemplary embodiments, in step 414, source DU102-11 may forward the received RRCReconfiguration message to UE104. Then, in step 416, UE104 may respond to source DU102-11 with an RRCReconfigurationComplete message, and in step 418, source DU102-11 may forward the RRCReconfigurationComplete message to source CU102-10 using a UL RRC message forwarding message. In some exemplary embodiments, source DU102-11 may use another message (for example, a UE context modification response message) instead of a UL RRC message forwarding message to send the RRCReconfigurationComplete message to source CU102-10.

[0115] In some exemplary embodiments, in step 420, source CU102-10 may send a handover request message (corresponding to the second request message in Figure 3) to candidate CU102-20. The handover request message may include an LTM indicator indicating that the request is for an LTM, the index of one or more LTM candidate cells, and the RS configuration. The LTM indicator may include a third code point that indicates to candidate CU102-20 to store the index and RS configuration of one or more LTM candidate cells. The third code point also indicates to candidate CU102-20 to forward the index and RS configuration of one or more LTM candidate cells to candidate DU102-21. For example, the third code point may be “LTM Store” or “LTM Forward”. In one example, the index and RS configuration of one or more LTM candidate cells may be included in the LTM indicator. In another example, the index and RS configuration of one or more LTM candidate cells may be included in the RRC context (HandoverPreparationInformation). In yet another example, the RS configuration may be included in the LTM candidate cell configuration of one or more LTM candidate cells (i.e., the index and LTM candidate cell configuration may be included in the LTM indicator or RRC context). In yet another example, source CU102-10 may use other messages (e.g., new UE-related signaling) to send the index and RS configuration of one or more LTM candidate cells to candidate CU102-20.

[0116] In some exemplary embodiments, in step 422, candidate CU102-20 may send a UE context modification request message (corresponding to the fourth request message in Figure 3) to candidate DU102-21, which includes the index and RS configuration of one or more LTM candidate cells. In step 424, candidate DU102-21 may respond to candidate CU102-20 with a UE context modification response message (corresponding to the fourth response message in Figure 3), and in step 426, candidate CU102-20 may send a handover request acknowledgment message (corresponding to the second response message in Figure 3) to source CU102-10. If the handover request message is not used in step 420, step 426 is optional, or another message may be used to respond.

[0117] Figure 4 shows that steps 420-426 are performed after steps 412-418, although steps 420-426 may be performed before or concurrently with any one of steps 412-418. After step 426, the preparation steps for LTM are completed.

[0118] In some exemplary embodiments, after the preparation steps for LTM are completed, in step 428, UE104 may send the L1 measurement results to source DU102-11. In step 430, source DU102-11 may decide to perform LTM on the target LTM candidate cell and, in step 432, send an LTM cell switch command (e.g., MAC CE) to UE104 that includes an index associated with the target LTM candidate cell. At this point, in step 434, source DU102-11 may send an LTM cell change notification message to source CU102-10 that includes the identifier of the target LTM candidate cell (e.g., target cell ID) to indicate to the UE that the LTM cell switch command has been initiated. In step 436, source CU102-10 may send an SN status transfer message, an early status transfer message, or other message including the target cell ID to candidate CU102-20 to indicate the target LTM candidate cell selected by source DU102-11 as the target cell for LTM cell switching. Subsequently, upon receiving user data sent from source CU102-10, candidate CU102-20 only needs to forward the user data to the candidate DU containing the target LTM candidate cell, rather than to all candidate DUs.

[0119] Figure 5 shows another example of a signaling procedure 500 for a preparation procedure for LTM according to an aspect of the present disclosure. Figure 5 relates to a candidate CU start modification of an interCU LTM candidate cell configuration.

[0120] In some exemplary embodiments, as shown in Figure 5, in step 502, candidate DU102-21 may send a UE context modification request message to candidate CU102-20 to request modification of one or more LTM candidate cell configurations. The UE context modification request message may include the NCGI of one or more LTM candidate cells to be revoked. That is, candidate CU102-20 will assume that resources reserved for these LTM candidate cells are about to be released by candidate DU102-21. Furthermore, the UE context modification request message may further include a cause value indicating the LTM resources to be changed. That is, candidate CU102-20 will assume that candidate DU102-21 is asking candidate CU102-20 to replace / update the existing LTM candidate cell configurations. In some exemplary embodiments, candidate DU102-21 may use other messages (e.g., a UE context release request message) to request modification of one or more LTM candidate cell configurations. In other words, the NCGI and cause value of one or more LTM candidate cells to be canceled may be included in the UE context release request message.

[0121] In some exemplary embodiments, in step 504, candidate CU102-20 may respond to candidate DU102-21 with a UE context modification confirmation message. However, if another message, such as a UE context release request message, is used in step 502, step 504 is not required.

[0122] In some exemplary embodiments, in step 506, candidate CU102-20 may send a conditional handover cancellation message to source CU102-10 to request a modification of the LTM candidate cell configuration. The conditional handover cancellation message may include an identifier (e.g., NCGI) of one or more LTM candidate cells to be cancelled. That is, source CU102-10 assumes that resources reserved for the LTM candidate cell are about to be released by candidate CU102-20. The conditional handover cancellation message may further include a cause value indicating the LTM resource to be modified. That is, source CU102-10 assumes that resources prepared for the LTM candidate cell configuration should be modified. In some exemplary embodiments, candidate CU102-20 may use other messages (e.g., new UE-related signaling) to request a modification of one or more LTM candidate cell configurations. Furthermore, candidate CU102-20 may decide to modify the LTM candidate cell configuration on its own, in which case steps 502 and 504 are not required.

[0123] After step 506, source CU102-10 may initiate the preparation procedures for the LTM described in Figures 3 and 4 (for example, steps 402-426).

[0124] Figure 6 shows an example of a device 600 supporting a preparation procedure for LTM according to an aspect of this disclosure. Device 600 may be an example of a source base station 102-1 as described herein. Device 600 may support wireless communication with one or more network entities 102 (e.g., candidate base stations 102-2 to 102-N) and UE 104. Device 600 may include components for bidirectional communication, including components for transmitting and receiving communications, such as a processor 602, memory 604, transceiver 606, and optionally an I / O controller 608. These components may communicate electronically via one or more interfaces (e.g., buses) or otherwise be coupled (e.g., operably, communicatively, functionally, electronically, electrically).

[0125] The processor 602, memory 604, transceiver 606, or various combinations thereof or various components thereof may be examples of means for carrying out various aspects of the disclosure described herein. For example, the processor 602, memory 604, transceiver 606, or various combinations thereof or components thereof may support a method for carrying out one or more of the operations described herein.

[0126] In some implementations, the processor 602, memory 604, transceiver 606, or various combinations or components thereof, may be implemented in hardware (for example, in a communication management circuit configuration). The hardware may include a processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, which may be configured as means for performing the functions described herein or otherwise supporting such means. In some implementations, the processor 602 and the memory 604 coupled with the processor 602 may be configured to perform one or more of the functions described herein (for example, the processor 602 executes instructions stored in the memory 604).

[0127] For example, the processor 602 may support wireless communication in device 600 according to the examples disclosed herein. The processor 602 may be configured to operate to support: means for transmitting one or more first request messages for one or more LTM candidate cells belonging to one or more candidate base stations 102-2 to 102-N, each via the transceiver 606, to one or more candidate base stations 102-2 to 102-N, respectively, wherein each first request message includes first LTM indication information and an identifier for the LTM candidate cell corresponding to the first request message; and means for receiving one or more first response messages for one or more LTM candidate cells via the transceiver 606, and from one or more candidate base stations 102-2 to 102-N, wherein the configuration information for each of the one or more LTM candidate cells is included in at least one first response message.

[0128] The processor 602 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some implementations, the processor 602 may be configured to operate a memory array using a memory controller. In some implementations, the memory controller may be integrated into the processor 602. The processor 602 may be configured to execute computer-readable instructions stored in memory (e.g., memory 604) to cause device 600 to perform various functions of this disclosure.

[0129] Memory 604 may include random access memory (RAM) and read-only memory (ROM). Memory 604 may store computer-readable computer-executable code, which, when executed by processor 602, causes device 600 to perform various functions described herein. The code may be stored in a non-temporary computer-readable medium, such as system memory or another type of memory. In some implementations, the code may not be directly executable by processor 602, but (for example, when compiled and executed) can cause the computer to perform the functions described herein. In some implementations, memory 604 may include a basic input / output system (BIOS) that can control basic hardware or software operations, in particular, interactions with peripheral components or peripheral devices.

[0130] The I / O controller 608 can manage input and output signals for device 600. The I / O controller 608 can also manage peripherals not integrated into device 600. In some implementations, the I / O controller 608 may represent physical connections or ports to external peripherals. In some implementations, the I / O controller 608 may use an operating system such as iOS®, ANDROID®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I / O controller 608 may be implemented as part of a processor, such as processor 602. In some implementations, a user may interact with device 600 via the I / O controller 608 or via hardware components controlled by the I / O controller 608.

[0131] In some implementations, device 600 may include a single antenna 610. However, in other implementations, device 600 may have two or more antennas 610 (e.g., multiple antennas), including multiple antenna panels or antenna arrays, and these antennas may be capable of simultaneously transmitting or receiving multiple wireless transmissions. Transceiver 606 may communicate bidirectionally via one or more antennas 610, wired or wireless links, as described herein. For example, transceiver 606 may represent a wireless transceiver and communicate bidirectionally with another wireless transceiver. Transceiver 606 may include a modem for modulating packets and providing the modulated packets to one or more antennas 610 for transmission, and for demodulating packets received from one or more antennas 610. Transceiver 606 may include one or more transmit chains, one or more receive chains, or a combination thereof.

[0132] The transmit chain may be configured to generate and transmit signals (e.g., control information, data, packets). The transmit chain may include at least one modulator for modulating data into a carrier signal and preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes such as phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmit chain may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. The transmit chain may also include one or more antennas 610 for transmitting the amplified signal to the air or a wireless medium.

[0133] The receiving chain may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiving chain may include one or more antennas 610 for receiving signals over air or a wireless medium. The receiving chain may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiving chain may include at least one demodulator configured to demodulate the received signal and to obtain transmitted data by inverting the modulation technique applied during the transmission of the signal. The receiving chain may include at least one decoder for decoding the demodulated signal to receive transmitted data.

[0134] Figure 7 shows an example of a device 700 supporting a preparation procedure for LTM according to an aspect of this disclosure. Device 700 may be an example of a candidate base station among the candidate base stations 102-2 to 102-N described herein. Device 700 may support wireless communication with UE 104 and source base station 102-1. Device 700 may include components for bidirectional communication, including components for transmitting and receiving communications, such as a processor 702, memory 704, transceiver 706, and optionally an I / O controller 708. These components may communicate electronically via one or more interfaces (e.g., buses) or otherwise be coupled (e.g., operably, communicatively, functionally, electronically, electrically).

[0135] The processor 702, memory 704, transceiver 706, or various combinations thereof or various components thereof may be examples of means for carrying out various aspects of the disclosure described herein. For example, the processor 702, memory 704, transceiver 706, or various combinations thereof or components thereof may support a method for carrying out one or more of the operations described herein.

[0136] In some implementations, the processor 702, memory 704, transceiver 706, or various combinations or components thereof, may be implemented in hardware (for example, in a communication management circuit configuration). The hardware may include a processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, which may be configured as means for performing the functions described herein or otherwise supporting such means. In some implementations, the processor 702 and the memory 704 coupled with the processor 702 may be configured to perform one or more of the functions described herein (for example, the processor 702 executes instructions stored in the memory 704).

[0137] For example, the processor 702 may support wireless communication in the device 700 according to the examples disclosed herein. The processor 702 may be configured to operate to support means for receiving a first request message from a source base station 102-1 for the LTM, via a transceiver 706, for an LTM candidate cell belonging to a candidate base station, wherein the first request message includes first LTM indication information and an identifier for the LTM candidate cell; means for preparing configuration information for the LTM candidate cell based on the first request message; and means for sending at least one first response message, including the configuration information for the LTM candidate cell, via the transceiver 706 and to the source base station 102-1.

[0138] The processor 702 may include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some implementations, the processor 702 may be configured to operate a memory array using a memory controller. In some implementations, the memory controller may be integrated into the processor 702. The processor 702 may be configured to execute computer-readable instructions stored in memory (e.g., memory 704) to cause device 700 to perform various functions of this disclosure.

[0139] Memory 704 may include random access memory (RAM) and read-only memory (ROM). Memory 704 may store computer-readable computer-executable code, which, when executed by processor 702, causes device 700 to perform various functions described herein. The code may be stored in a non-temporary computer-readable medium, such as system memory or another type of memory. In some implementations, the code may not be directly executable by processor 702, but (for example, when compiled and executed) may cause the computer to perform the functions described herein. In some implementations, memory 704 may include a basic input / output system (BIOS) that may control basic hardware or software operations, in particular, interactions with peripheral components or peripheral devices.

[0140] The I / O controller 708 can manage input and output signals for device 700. The I / O controller 708 can also manage peripherals not integrated into device 700. In some implementations, the I / O controller 708 may represent a physical connection to an external peripheral or a port to an external peripheral. In some implementations, the I / O controller 708 may use an operating system such as iOS®, ANDROID®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I / O controller 708 may be implemented as part of a processor, such as processor 706. In some implementations, a user may interact with device 700 via the I / O controller 708 or via hardware components controlled by the I / O controller 708.

[0141] In some implementations, device 700 may include a single antenna 710. However, in other implementations, device 700 may have two or more antennas 710 (e.g., multiple antennas), including multiple antenna panels or antenna arrays, and these antennas may be capable of simultaneously transmitting or receiving multiple wireless transmissions. Transceiver 706 may communicate bidirectionally with one or more antennas 710, wired or wireless links, as described herein. For example, transceiver 706 may represent a wireless transceiver and communicate bidirectionally with another wireless transceiver. Transceiver 706 may include a modem for demodulating packets received from one or more antennas 710, and for modulating packets and providing the modulated packets to one or more antennas 710 for transmission. Transceiver 706 may include one or more transmit chains, one or more receive chains, or a combination thereof.

[0142] The transmit chain may be configured to generate and transmit signals (e.g., control information, data, packets). The transmit chain may include at least one modulator for modulating data into a carrier signal and preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques, such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes such as phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmit chain may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over a wireless medium. The transmit chain may also include one or more antennas 710 for transmitting the amplified signal to the air or a wireless medium.

[0143] A receiving chain may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, a receiving chain may include one or more antennas 710 for receiving signals over air or a wireless medium. A receiving chain may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. A receiving chain may include at least one demodulator configured to demodulate the received signal and to obtain transmitted data by inverting the modulation technique applied during the transmission of the signal. A receiving chain may include at least one decoder for decoding the demodulated signal to receive transmitted data.

[0144] Figure 8 shows an example of a processor 800 supporting a preparation procedure for LTM according to an aspect of this disclosure. The processor 800 may be an example of a processor configured to perform various operations according to the examples described herein. The processor 800 may include a controller 802 configured to perform various operations according to the examples described herein. The processor 800 may optionally include at least one memory 804, such as an L1 / L2 / L3 cache. Additionally or alternatively, the processor 800 may optionally include one or more arithmetic logic units (ALUs) 806. One or more of these components may communicate electronically via one or more interfaces (e.g., buses) or otherwise be coupled (e.g., operationally, communicatively, functionally, electronically, electrically).

[0145] The processor 800 may be a processor chipset, which may include a protocol stack (e.g., a software stack) that is executed by the processor chipset to perform various operations as described herein (e.g., receive, acquire, retrieve, transmit, output, forward, store, decide, identify, access, write, read). The processor chipset may include one or more cores, one or more caches (e.g., the processor chipset (e.g., processor 800) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase-change memory (PCM), etc., which are local to or contained therein)).

[0146] The controller 802 may be configured to manage and coordinate various operations of the processor 800 (e.g., signaling, receiving, acquiring, retrieving, transmitting, outputting, forwarding, storing, deciding, identifying, accessing, writing, and reading) so that the processor 800 supports various base station operations as described herein. For example, the controller 802 may act as a control unit for the processor 800 and generate control signals that manage the operation of various components of the processor 800. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating the timing of operations.

[0147] The controller 802 may be configured to fetch instructions from memory 804 (e.g., acquire, retrieve, receive) and to determine subsequent instructions to be executed so that the processor 800 can support various operations as illustrated herein. The controller 802 may be configured to track the memory addresses of instructions associated with memory 804. The controller 802 may be configured to decode instructions to determine the operations to be performed and the operands involved. For example, the controller 802 may be configured to translate instructions and to determine control signals to be output to other components of the processor 800 so that the processor 800 can support various operations as illustrated herein. Additionally or alternatively, the controller 802 may be configured to manage the flow of data within the processor 800. The controller 802 may be configured to control the transfer of data between registers, arithmetic logic units (ALUs), and other functional units of the processor 800.

[0148] Memory 804 may include one or more caches (for example, memory local to or contained within the processor 800), or other memory such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, or flash memory. In some implementations, memory 804 may be located within or on the processor chipset (for example, local to the processor 800). In some other implementations, memory 804 may be located outside the processor chipset (for example, remote to the processor 800).

[0149] Memory 804 may store computer-readable computer-executable code, which, when executed by processor 800, causes processor 800 to perform various functions described herein. The code may be stored in a non-temporary computer-readable medium, such as system memory or another type of memory. Controller 802 and / or processor 800 may be configured to execute computer-readable instructions stored in memory 804 for causing processor 800 to perform various functions. For example, processor 800 and / or controller 802 may be coupled to or with memory 804, and processor 800, controller 802, and memory 804 may be configured to perform various functions described herein. In some examples, processor 800 may include multiple processors, and memory 804 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, and they may be configured individually or collectively to perform various functions described herein.

[0150] One or more ALU800s may be configured to support various operations as illustrated in the examples described herein. In some implementations, one or more ALU800s may be located within or on a processor chipset (e.g., processor 800). In some other implementations, one or more ALU800s may be located outside the processor chipset (e.g., processor 800). One or more ALU800s may perform one or more operations on data, such as addition, subtraction, multiplication, and division. For example, one or more ALU800s may receive input operands and operation codes, which determine the operation to be performed. One or more ALU800s may consist of various logic and arithmetic circuits, including adders, subtractors, shifters, and logic gates, for processing and handling data according to the operations. As an addition or alternative, one or more ALU800s may support logical operations such as AND, OR, exclusive OR (XOR), not-OR (NOR), and not-AND (NAND), enabling one or more ALU800s to handle conditional operations, comparisons, and bitwise operations.

[0151] The processor 800 may support wireless communication as illustrated herein. The processor 800 may be configured to support, or be operable to support, one or more first request messages for one or more LTM candidate cells belonging to one or more candidate base stations 102-2 to 102-N, each via the transceiver 606, to one or more candidate base stations 102-2 to 102-N, respectively, wherein each first request message includes first LTM indication information and an identifier for the LTM candidate cell corresponding to the first request message; and one or more first response messages for one or more LTM candidate cells via the transceiver 606 and from one or more candidate base stations 102-2 to 102-N, wherein the configuration information for each of the one or more LTM candidate cells is included in at least one first response message.

[0152] Figure 9 shows an example of a processor 900 supporting a preparation procedure for LTM according to an aspect of this disclosure. The processor 900 may be an example of a processor configured to perform various operations according to the examples described herein. The processor 900 may include a controller 902 configured to perform various operations according to the examples described herein. The processor 900 may optionally include at least one memory 904, such as an L1 / L2 / L3 cache. Additionally or alternatively, the processor 900 may optionally include one or more arithmetic logic units (ALUs) 906. One or more of these components may communicate electronically via one or more interfaces (e.g., buses) or otherwise be coupled (e.g., operationally, communicatively, functionally, electronically, electrically).

[0153] The processor 900 may be a processor chipset, which may include a protocol stack (e.g., a software stack) that is executed by the processor chipset to perform various operations as described herein (e.g., receive, acquire, retrieve, transmit, output, forward, store, decide, identify, access, write, read). The processor chipset may include one or more cores, one or more caches (e.g., memory that is local to or contained in the processor chipset (e.g., processor 900) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase-change memory (PCM), etc.)).

[0154] The controller 902 may be configured to manage and coordinate various operations of the processor 900 (e.g., signaling, receiving, acquiring, retrieving, transmitting, outputting, forwarding, storing, deciding, identifying, accessing, writing, and reading) so that the processor 900 supports various operations of the UE as described herein. For example, the controller 902 may act as a control unit for the processor 900 and generate control signals that manage the operation of various components of the processor 900. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating the timing of operations.

[0155] The controller 902 may be configured to fetch instructions from memory 904 (e.g., acquire, retrieve, receive) and to determine subsequent instructions to be executed so that the processor 900 can support various operations as illustrated herein. The controller 902 may be configured to track the memory address of the instruction associated with memory 904. The controller 902 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 902 may be configured to translate instructions and to determine control signals to be output to other components of the processor 900 so that the processor 900 can support various operations as illustrated herein. Additionally or alternatively, the controller 902 may be configured to manage the flow of data within the processor 900. The controller 902 may be configured to control the transfer of data between registers, arithmetic logic units (ALUs), and other functional units of the processor 900.

[0156] Memory 904 may include one or more caches (for example, memory local to or contained within the processor 900), or other memory such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, or flash memory. In some implementations, memory 904 may be located within or on the processor chipset (for example, local to the processor 900). In some other implementations, memory 904 may be located outside the processor chipset (for example, the processor 900).

[0157] Memory 904 may store computer-readable computer-executable code, which, when executed by processor 900, causes processor 900 to perform various functions described herein. The code may be stored in a non-temporary computer-readable medium, such as system memory or another type of memory. Controller 902 and / or processor 900 may be configured to execute computer-readable instructions stored in memory 904 to cause processor 900 to perform various functions. For example, processor 900 and / or controller 902 may be coupled to or with memory 904, and processor 900, controller 902, and memory 904 may be configured to perform various functions described herein. In some examples, processor 900 may include multiple processors, and memory 904 may include multiple memories. One or more of the multiple processors may be coupled to one or more of the multiple memories, and they may be configured individually or collectively to perform various functions described herein.

[0158] One or more ALU906s may be configured to support various operations as illustrated in the examples described herein. In some implementations, one or more ALU906s may be located within or on a processor chipset (e.g., processor 900). In some other implementations, one or more ALU906s may be located outside the processor chipset (e.g., processor 900). One or more ALU906s may perform one or more operations on data, such as addition, subtraction, multiplication, and division. For example, one or more ALU906s may receive input operands and operation codes, which determine the operation to be performed. One or more ALU906s may consist of various logic and arithmetic circuits, including adders, subtractors, shifters, and logic gates, for processing and handling data according to the operations. As an addition or alternative, one or more ALU906s may support logical operations such as AND, OR, exclusive OR (XOR), not-OR (NOR), and not-AND (NAND), enabling one or more ALU906s to handle conditional operations, comparisons, and bitwise operations.

[0159] The processor 900 may support wireless communication as illustrated herein. The processor 900 may be configured or operable to support means for receiving a first request message from a source base station 102-1 for a candidate LTM via a transceiver 706 and for an LTM candidate cell, wherein the first request message includes first LTM indication information and an identifier for the LTM candidate cell; means for preparing configuration information for the LTM candidate cell based on the first request message; and means for sending at least one first response message including the configuration information for the LTM candidate cell via the transceiver 706 and to the source base station 102-1.

[0160] Figure 10 shows a flowchart of Method 1000 supporting a preparation procedure for LTM according to an aspect of this disclosure. The operation of Method 1000 may be carried out by a device or its components, as described herein. For example, the operation of Method 1000 may be carried out by a source base station 102-1, as described herein. In some implementations, the device may execute a set of instructions for controlling the functional elements of the device to perform the described functions. In addition or alternatively, the device may use dedicated hardware to perform aspects of the described functions.

[0161] In 1005, the method may include the step of sending one or more first request messages to one or more candidate base stations 102-2 to 102-N for LTM, each for one or more LTM candidate cells belonging to one or more candidate base stations 102-2 to 102-N, each first request message including first LTM indication information and an identifier for the LTM candidate cell corresponding to the first request message. The operation of 1005 may be carried out according to the examples described herein. In some implementations, the operation of 1005 may be carried out by the device described with reference to Figure 1.

[0162] In 1010, the method may include the step of receiving one or more first response messages for one or more LTM candidate cells from one or more candidate base stations 102-2 to 102-N, wherein the configuration information of each of the one or more LTM candidate cells is included in at least one first response message. The operation of 1010 may be carried out according to the examples described herein. In some implementations, the operation of 1010 may be carried out by the device described with reference to Figure 1.

[0163] Figure 11 shows a flowchart of Method 1100 supporting a preparation procedure for LTM according to an aspect of this disclosure. The operation of Method 1100 may be carried out by a device or its components, as described herein. For example, the operation of Method 1100 may be carried out by any one of the candidate base stations 102-2 to 102-N, as described herein. In some implementations, the device may execute a set of instructions for controlling the functional elements of the device to perform the described functions. In addition or alternatively, the device may perform aspects of the described functions using dedicated hardware.

[0164] In 1105, the method may include the step of receiving a first request message from a source base station 102-1 for LTM regarding LTM candidate cells belonging to a candidate base station, the first request message including first LTM indication information and an identifier for the LTM candidate cell. The operation of 1105 may be carried out according to the examples described herein. In some implementations, the operation of 1105 may be carried out by a device described with reference to Figure 1.

[0165] In 1110, the method may include the step of preparing configuration information for an LTM candidate cell based on a first request message. The operation of 1110 may be carried out according to the examples described herein. In some implementations, the operation of 1110 may be carried out by the device described with reference to Figure 1.

[0166] In 1115, the method may include the step of sending at least one first response message containing configuration information of the LTM candidate cell to the source base station 102-1. The operation of 1110 may be carried out according to the examples described herein. In some implementations, the operation of 1110 may be carried out by the device described with reference to Figure 1.

[0167] It should be noted that the methods described herein represent possible implementations, that the operations and steps may be rearranged or possibly modified, and that other implementations are possible. Furthermore, two or more embodiments of these methods may be combined.

[0168] The various exemplary blocks and components described in this disclosure may be implemented or carried out using general-purpose processors, DSPs, ASICs, CPUs, FPGAs or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors working with a DSP core, or any other such configuration).

[0169] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or a combination thereof. When implemented in software executed by a processor, the functions may be stored in or transmitted through a computer-readable medium as one or more instructions or codes. Other examples and implementations fall within the scope of this disclosure and the accompanying claims. For example, due to the nature of the software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or a combination thereof. The features implementing the functions may also be physically located in various locations, including the distribution of parts of the functions so that they are implemented in various physical locations.

[0170] Computer-readable media include both non-temporary computer storage media and communication media, including any media that facilitate the transfer of computer programs from one location to another. Non-temporary storage media can be any available media that can be accessed by a general-purpose or dedicated computer. For example, non-temporary computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-temporary media that can be used to carry or store desired program code means in the form of instructions or data structures, and can be accessed by a general-purpose or dedicated computer or a general-purpose or dedicated processor.

[0171] As used herein, including in the claims, the article “a” preceding an element is unrestricted and is understood to refer to “at least one” of those elements or “one or more” of those elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” may be interchangeable. As used herein, including in the claims, “or” used in a list of items (for example, a list of items ending with a phrase such as “at least one of,” “one or more of,” or “one or both of”) indicates an inclusive list, for example, such that a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” should not be interpreted as a reference to a closed set of conditions. For example, an exemplary step described as “based on condition A” may be based on both condition A and condition B without departing from the scope of this disclosure. In other words, as used herein, the phrase “based on” should be construed in the same way as the phrase “at least partially based on.” Furthermore, as used herein, including in the claims, “set” may include one or more elements.

[0172] The descriptions herein are provided to enable those skilled in the art to create or use this disclosure. Various modifications of this disclosure will become apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of this disclosure. Accordingly, this disclosure should be given the broadest scope that is consistent with the principles and novel features disclosed herein, and is not limited to the examples and designs described herein. [Explanation of Symbols]

[0173] 100 Wireless Communication Systems 102 Network Entities 102-1 Source Base Station 102-2~102-N Candidate base station 102-10 Source CU 102-11 Source DU 102-20 Candidate CU 102-21 Candidate DU 104 User Equipment (UE) 106 Core Network 108 Packet Data Network 110 Communication Link 112 Geographic Coverage Areas 114 Communication Link 116 Backhaul Link 118 Application Server 160 CU 600 devices 602 Processors 604 memory 606 Transceiver 608 I / O Controller 610 Antenna 700 devices 702 Processor 704 memory 706 Transceiver 708 I / O Controller 710 Antenna 800 processors, arithmetic logic units (ALUs) 802 Controller 804 memory 610 Antenna 806 Arithmetic Logic Unit (ALU) 900 processor 902 Controller 904 memory 906 Arithmetic Logic Unit (ALU)

Claims

1. Processor and A transceiver coupled to the aforementioned processor and A base station equipped with, The base station is a source base station for Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM), the processor is configured to perform LTM preparation procedures, and the LTM preparation procedures are: Transmitting one or more first request messages via the transceiver and to one or more candidate base stations for LTM, for one or more LTM candidate cells belonging to one or more candidate base stations, wherein each first request message includes first LTM indication information and an identifier for the LTM candidate cell corresponding to the first request message. Receiving one or more first response messages for the one or more LTM candidate cells via the transceiver and from the one or more candidate base stations, wherein the configuration information of each of the one or more LTM candidate cells is included in at least one first response message. Base stations, including

2. The base station according to claim 1, wherein the configuration information of the LTM candidate cell includes at least one of the LTM candidate cell configuration and the reference signal (RS) configuration of the LTM candidate cell.

3. The aforementioned LTM preparation procedure is: The base station according to claim 2, further comprising assigning an index to one or more LTM candidate cell configurations of the one or more LTM candidate cells.

4. The aforementioned LTM preparation procedure is: The base station according to claim 3, further comprising transmitting a second request message via the transceiver and to each of the one or more candidate base stations, the second LTM indication information, the index of the one or more LTM candidate cell configurations, and the RS configuration of the one or more LTM candidate cells.

5. The first LTM indication information is an LTM indicator having a first code point or a second code point, the first code point indicating the initiation of preparation of the LTM candidate cell configuration, and the second code point indicating the update of the LTM candidate cell configuration. The base station according to claim 4, wherein the second LTM indication information is the LTM indicator having a third code point, the third code point indicates storing the index of the one or more LTM candidate cell configurations and the RS configuration of the one or more LTM candidate cells.

6. The aforementioned processor, The base station according to any one of claims 1 to 5, further configured to perform the LTM preparation procedure when a withdrawal message requesting a modification of the LTM candidate cell configuration is received from a candidate base station for LTM, wherein the withdrawal message includes identifiers of one or more LTM candidate cells to be withdrawn.

7. The base station according to claim 6, wherein the cancellation message further includes a cause value indicating the LTM resource to be modified.

8. The aforementioned processor, The base station according to claim 3, further configured to transmit an identifier of the target LTM candidate cell via the transceiver and to a candidate base station corresponding to the target LTM candidate cell when it decides to perform an LTM to the target LTM candidate cell.

9. Processor and A transceiver coupled to the aforementioned processor and A base station equipped with, The base station is a candidate base station for Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM), the processor is configured to perform an LTM preparation procedure, and the LTM preparation procedure is: Receiving a first request message for an LTM candidate cell belonging to the candidate base station via the transceiver and from the source base station for LTM, wherein the first request message includes first LTM indication information and an identifier for the LTM candidate cell. Based on the first request message, prepare the configuration information of the LTM candidate cell, Transmitting at least one first response message containing the configuration information of the LTM candidate cell via the transceiver and to the source base station. Base stations, including

10. The base station according to claim 9, wherein the configuration information includes at least one of the LTM candidate cell configuration and the reference signal (RS) configuration of the LTM candidate cell.

11. The aforementioned LTM preparation procedure is: Receiving a second request message via the transceiver and from the source base station, which includes second LTM indication information, the RS configuration of one or more LTM candidate cells identified by the source base station, and an index of one or more LTM candidate cell configurations of the one or more LTM candidate cells identified by the source base station, The index of the one or more LTM candidate cell configurations and the RS configuration of the one or more LTM candidate cells are stored. The base station according to claim 10, further comprising:

12. The first LTM indication information is an LTM indicator having a first code point or a second code point, the first code point indicating the initiation of preparation of the LTM candidate cell configuration, and the second code point indicating the update of the LTM candidate cell configuration. The base station according to claim 11, wherein the second LTM indication information is the LTM indicator having a third code point, the third code point indicates storing the index of the one or more LTM candidate cell configurations and the RS configuration of the one or more LTM candidate cells.

13. Storing the index of the one or more LTM candidate cell configurations and the RS configuration of the one or more LTM candidate cells is Sending a fourth request message from the candidate central unit (CU) of the candidate base station to the candidate distributed unit (DU) of the candidate base station corresponding to the LTM candidate cell, including the index of the one or more LTM candidate cell configurations and the RS configuration of the one or more LTM candidate cells, In the candidate DU, the index of the one or more LTM candidate cell configurations and the RS configuration of the one or more LTM candidate cells are stored. A base station according to claim 11, including the above.

14. The aforementioned processor, The transceiver is further configured to send a cancellation message requesting modification of the LTM candidate cell configuration to the source base station, The base station according to claim 9, wherein the cancellation message includes identifiers of one or more LTM candidate cells to be cancelled.

15. The base station according to claim 14, wherein the cancellation message further includes a cause value indicating the LTM resource to be modified.

16. The base station according to claim 15, wherein the cancellation message is generated by the candidate CU in response to receiving a correction message from a candidate DU belonging to the candidate CU requesting a modification of one or more LTM candidate cell configurations.

17. The base station according to claim 16, wherein the correction message includes a cause value indicating the LTM resource to be changed.

18. The aforementioned processor, The base station according to claim 9, further configured to receive, via the transceiver and from the source base station, the identifier of the target LTM candidate cell when the source base station decides to perform an LTM to the target LTM candidate cell.

19. A method implemented by a source base station for Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM), the method comprising an LTM preparation procedure, the LTM preparation procedure comprising: Transmitting one or more first request messages via a transceiver and to one or more candidate base stations for LTM, for one or more LTM candidate cells belonging to the one or more candidate base stations, wherein each first request message includes first LTM indication information and an identifier for the LTM candidate cell corresponding to the first request message. Receiving one or more first response messages for the one or more LTM candidate cells via the transceiver and from the one or more candidate base stations, wherein the configuration information of each of the one or more LTM candidate cells is included in at least one first response message. Methods that include...

20. A method implemented by a candidate base station for Layer 1 / Layer 2 (L1 / L2) triggered mobility (LTM), the method comprising an LTM preparation procedure, the LTM preparation procedure comprising: Receiving a first request message for an LTM candidate cell belonging to the candidate base station via a transceiver and from a source base station for LTM, wherein the first request message includes first LTM indication information and an identifier for the LTM candidate cell. Based on the first request message, prepare the configuration information of the LTM candidate cell, Transmitting at least one first response message containing the configuration information of the LTM candidate cell via the transceiver and to the source base station. Methods that include...

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