Multi-TRP method for acquisition by TA

Abstract

The invention relates to a multi-TRP method and apparatus for obtaining through a TA. The device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: receive, from a network node, an indication to monitor a likelihood of configuring a user device for a single transmission receive point operation, or receiving, from the network node, an indication to monitor a likelihood of configuring the user equipment for the multi-transmit-receive-point operation; determining whether it is possible to configure the user equipment for a single-transmit-receive-point operation or a multi-transmit-receive-point operation; and transmitting an indication to the network node that it is possible to configure the user equipment for the single-transmit-receive-point operation or the multi-transmit-receive-point operation.

Description

Technical Field

[0001] The exemplary and non-limiting exemplary embodiments relate generally to communications, and more particularly, to methods for multiple TRPs acquired through a TA. Background Art

[0002] The transmission and reception timing of network nodes in a synchronous communication network is known. Summary of the invention

[0003] According to one aspect, an apparatus includes: at least one processor; and at least one memory storing instructions. When the instructions are executed by the at least one processor, the apparatus at least: receives an indication from a network node to monitor the possibility of configuring a user equipment for single transmission reception point operation, or receives an indication from a network node to monitor the possibility of configuring a user equipment for multiple transmission reception point operation; determines whether it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; and transmits to the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation.

[0004] According to one aspect, an apparatus includes: at least one processor; and at least one memory storing instructions. When the instructions are executed by the at least one processor, the apparatus at least: transmits to a network node an indication for monitoring the possibility of configuring a user equipment for single transmission reception point operation, or transmits to the network node an indication for monitoring the possibility of configuring the user equipment for multiple transmission reception point operation; receives from the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; and configures the user equipment for single transmission reception point operation or multiple transmission reception point operation based on the indication received from the network node.

[0005] According to one aspect, an apparatus includes: at least one processor; and at least one memory storing instructions. When the instructions are executed by the at least one processor, the apparatus at least: provides access to a first candidate cell and a second candidate cell; and performs at least one of the following: receives an instruction to configure a single transmission reception point operation for a user equipment when the user equipment has acquired a timing advance for the first candidate cell but failed to acquire a timing advance for the second candidate cell, or receives an instruction to configure a multi-transmission reception point operation for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell when the user equipment has acquired a timing advance for the first candidate cell but failed to acquire a timing advance for the second candidate cell; and performs a single transmission reception point operation or a multi-transmission reception point operation with the user equipment.

[0006] According to one aspect, an apparatus includes: at least one processor; and at least one memory storing instructions. When the instructions are executed by the at least one processor, the apparatus at least: receives an instruction to acquire a timing advance for a first candidate cell and a timing advance for a second candidate cell; in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performs a single transmission reception point operation with the first candidate cell; and in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performs a multiple transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell.

[0007] According to one aspect, a method includes: receiving an indication from a network node to monitor the possibility of configuring a user equipment for single transmission reception point operation, or receiving an indication from a network node to monitor the possibility of configuring the user equipment for multiple transmission reception point operation; determining whether it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; and transmitting to the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation.

[0008] According to one aspect, a method includes: transmitting to a network node an indication for monitoring the possibility of configuring a user equipment for single transmission reception point operation, or transmitting to the network node an indication for monitoring the possibility of configuring the user equipment for multiple transmission reception point operation; receiving from the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; and configuring the user equipment for single transmission reception point operation or multiple transmission reception point operation based on the indication received from the network node.

[0009] According to one aspect, a method includes: providing access to a first candidate cell and a second candidate cell; and performing at least one of the following: receiving an indication to configure a single transmission reception point operation for a user equipment when the user equipment has acquired a timing advance for the first candidate cell but failed to acquire a timing advance for the second candidate cell, or receiving an indication to configure a multiple transmission reception point operation for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell when the user equipment has acquired a timing advance for the first candidate cell but failed to acquire a timing advance for the second candidate cell; and performing the single transmission reception point operation or the multiple transmission reception point operation with the user equipment.

[0010] According to one aspect, a method includes: receiving an indication to acquire a timing advance for a first candidate cell and a timing advance for a second candidate cell; in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performing a single transmission reception point operation with the first candidate cell; and in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performing a multiple transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell.

[0011] According to one aspect, an apparatus includes: a component for receiving an indication from a network node to monitor the possibility of configuring a user equipment for single transmission reception point operation, or receiving an indication from a network node to monitor the possibility of configuring a user equipment for multiple transmission reception point operation; a component for determining whether it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; and a component for transmitting to the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation.

[0012] According to one aspect, an apparatus includes: a component for transmitting to a network node an indication for monitoring the possibility of configuring a user equipment for single transmission reception point operation, or transmitting to a network node an indication for monitoring the possibility of configuring a user equipment for multiple transmission reception point operation; a component for receiving from the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; and a component for configuring the user equipment for single transmission reception point operation or multiple transmission reception point operation based on the indication received from the network node.

[0013] According to one aspect, an apparatus includes: a component for providing access to a first candidate cell and a second candidate cell; and a component for performing at least one of the following: receiving an indication for configuring a single transmission reception point operation for a user equipment when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell, or receiving an indication for configuring a multiple transmission reception point operation for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell; and a component for performing a single transmission reception point operation or a multiple transmission reception point operation with the user equipment.

[0014] According to one aspect, an apparatus includes: a component for receiving an indication to acquire a timing advance for a first candidate cell and a timing advance for a second candidate cell; a component for performing a single transmission reception point operation with the first candidate cell in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell; and a component for performing a multiple transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell.

[0015] According to one aspect, a machine-readable, non-transitory program storage device is provided and described, tangibly embodying a machine-executable program of instructions for performing operations, the operations comprising: receiving an indication from a network node to monitor the possibility of configuring a user device for single transmission reception point operation, or receiving an indication from a network node to monitor the possibility of configuring a user device for multiple transmission reception point operation; determining whether it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation; and transmitting to the network node an indication that it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation.

[0016] According to one aspect, a machine-readable, non-transitory program storage device is provided and described, tangibly embodying a machine-executable program of instructions for performing operations, the operations comprising: transmitting to a network node an indication for monitoring the possibility of configuring a user device for single transmission reception point operation, or transmitting to a network node an indication for monitoring the possibility of configuring a user device for multiple transmission reception point operation; receiving from the network node an indication that it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation; and configuring the user device for single transmission reception point operation or multiple transmission reception point operation based on the indication received from the network node.

[0017] According to one aspect, a machine-readable non-transitory program storage device is provided and described, tangibly embodying a machine-executable instruction program for performing operations, the operations including: providing access to a first candidate cell and a second candidate cell; and performing at least one of the following: receiving an indication to configure a single transmission reception point operation for a user equipment when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell, or receiving an indication to configure a multiple transmission reception point operation for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell; and performing a single transmission reception point operation or a multiple transmission reception point operation with the user equipment.

[0018] According to one aspect, a machine-readable, non-transitory program storage device is provided and described, tangibly embodying a program of instructions executable by the machine for performing operations, the operations comprising: receiving an indication to acquire a timing advance for a first candidate cell and a timing advance for a second candidate cell; in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performing a single transmission reception point operation with the first candidate cell; and in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performing a multiple transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The foregoing aspects and other features are explained in the following description in conjunction with the accompanying drawings.

[0020] Figure 1 is a block diagram of one possible and non-limiting system in which example embodiments may be practiced.

[0021] Figure 2 is an exemplary signaling diagram of L1 / 2 triggered mobility (LTM).

[0022] Figure 3 is a message sequence chart used to trigger an sTRP operation or an mTRP operation in case of a retry on RACH.

[0023] Figure 4 is a message sequence chart used to trigger mTRP configuration after UE measurement.

[0024] Figure 5 is a message sequence chart used to trigger mTRP configuration after TA acquisition.

[0025] Figure 6 is an example apparatus configured to implement the examples described in this disclosure.

[0026] Figure 7 A representation of an example of a non-volatile storage medium for storing instructions to implement the examples described herein is shown.

[0027] Figure 8 is an example method based on the examples described in this disclosure.

[0028] Fig. 9 is an example method based on the examples described in this disclosure.

[0029] Fig.10 is an example method based on the examples described in this disclosure.

[0030] Fig.11is an example method based on the examples described in this disclosure. DETAILED DESCRIPTION

[0031] Go to Figure 1 , which shows a block diagram of one possible and non-limiting example in which the example may be practiced. A user equipment (UE) 110, a radio access network (RAN) node 170 and a network element 190 are shown. Figure 1 In the example of , a user equipment (UE) 110 wirelessly communicates with a wireless network 100. A UE is a wireless device that can access the wireless network 100. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected by one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. The one or more buses 127 can be address, data, or control buses, and can include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, an optical fiber or other optical communication device, etc. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a module 140, which includes one or both of the parts 140-1 and / or 140-2, which can be implemented in a variety of ways. The module 140 can be implemented in hardware as the module 140-1, for example, as part of one or more processors 120. Module 140-1 may also be implemented as an integrated circuit or by other hardware (such as a programmable gate array). In another example, module 140 may be implemented as module 140-2, which is implemented as computer program code 123 and executed by one or more processors 120. For example, one or more memories 125 and computer program code 123 may be configured to perform one or more operations as described in the present disclosure with one or more processors 120 using user equipment 110. UE 110 communicates with RAN node 170 via wireless link 111.

[0032] The RAN node 170 in this example is a base station that provides access to the wireless network 100 for wireless devices such as UE 110. The RAN node 170 may be, for example, a base station for 5G, also known as New Radio (NR). In 5G, the RAN node 170 may be a NG-RAN node, which is defined as a gNB or ng-eNB. A gNB is a node that provides NR user plane and control plane protocol termination to a UE and is connected to a 5GC (such as, for example, network element (s) 190) via an NG interface (such as connection 131). An ng-eNB is a node that provides E-UTRA user plane and control plane protocol termination to a UE and is connected to a 5GC via an NG interface (such as connection 131). An NG-RAN node may include multiple gNBs, which may also include a central unit (CU) (gNB-CU) 196 and a distributed unit (DU) (gNB-DU), of which DU 195 is shown. Note that the DU 195 may include or be coupled to and control a radio unit (RU). The gNB-CU 196 is a logical node that hosts the radio resource control (RRC), SDAP and PDCP protocols of the gNB or the RRC and PDCP protocols of the en-gNB that controls the operation of one or more gNB-DUs. The gNB-CU 196 terminates the F1 interface connected to the gNB-DU 195. The F1 interface is shown as reference numeral 198, although reference numeral 198 also shows a link between a remote element of the RAN node 170 and a centralized element of the RAN node 170 (such as between the gNB-CU 196 and the gNB-DU 195). The gNB-DU 195 is a logical node that hosts the RLC, MAC, and PHY layers of the gNB or en-gNB, and its operation is controlled in part by the gNB-CU 196. One gNB-CU 196 supports one or more cells. One cell can be supported by one gNB-DU 195, or one cell can be supported / shared by multiple DUs under RAN sharing. The gNB-DU 195 terminates the F1 interface 198 connected to the gNB-CU 196. Note that the DU 195 is considered to include the transceiver 160, for example as part of the RU, but some examples thereof may have the transceiver 160 as part of a separate RU, for example under the control of the DU 195 and connected to the DU 195. The RAN node 170 may also be an eNB (evolved Node B) base station for LTE (Long Term Evolution) or any other suitable base station or node.

[0033] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N / WI / F) 161, and one or more transceivers 160 interconnected by one or more buses 157. Each of the one or more transceivers 160 includes a receiver Rx 162 and a transmitter Tx 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 may include the processor 152, the one or more memories 155, and the network interface 161. Note that the DU 195 may also contain its own one or more memories and processors and / or other hardware, but these are not shown.

[0034] The RAN node 170 includes a module 150, which includes one or both of the parts 150-1 and / or 150-2, which can be implemented in a variety of ways. The module 150 can be implemented in hardware as a module 150-1, for example, as part of one or more processors 152. The module 150-1 can also be implemented as an integrated circuit or by other hardware (such as a programmable gate array). In another example, the module 150 can be implemented as a module 150-2, which is implemented as a computer program code 153 and executed by one or more processors 152. For example, one or more memories 155 and the computer program code 153 are configured to, together with the one or more processors 152, cause the RAN node 170 to perform one or more operations as described herein. Note that the functionality of the module 150 can be distributed, such as distributed between the DU 195 and the CU 196, or implemented only in the DU 195.

[0035] One or more network interfaces 161 communicate over a network, such as via links 176 and 131. Two or more gNBs 170 may communicate using, for example, link 176. Link 176 may be wired or wireless or both, and may implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interfaces for other standards.

[0036] The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of wires on a motherboard or integrated circuit, optical fiber or other optical communication device, wireless channel, etc. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for a gNB implementation for 5G, where other elements of the RAN node 170 may be physically located in a different location from the RRH / DU 195, and the one or more buses 157 may be partially implemented as, for example, fiber optic cables or other suitable network connections to connect other elements of the RAN node 170 (e.g., central unit (CU), gNB-CU 196) to the RRH / DU 195. Reference numeral 198 also indicates those suitable network links.

[0037] The RAN node / gNB may include one or more TRPs to which the methods described in the present disclosure may be applied. Figure 1 RAN node 170 is shown to include TRP51 and TRP52 in addition to the TRP represented by transceiver 160. Similar to transceiver 160, TRP51 and TRP52 may each include a transmitter and a receiver. RAN node 170 may host or include Figure 1 Other TRPs not shown.

[0038] The relay nodes in NR are called integrated access and backhaul nodes. The mobile terminal part of the IAB node facilitates the backhaul (parent link) connection. In other words, the mobile terminal part includes the functionality of carrying UE functions. The distributed unit part of the IAB node facilitates the so-called access link (sub-link) connection (i.e., in the case of multi-hop IAB, for access link UE, and for backhaul of other IAB nodes). In other words, the distributed unit part is responsible for certain base station functions. The IAB scenario can follow a so-called split architecture, where the central unit hosts higher layer protocols to the UE and terminates the control plane and user plane interfaces to the 5G core network.

[0039] Note that the description herein indicates that a "cell" performs a function, but it should be clear that the devices that form the cell can perform the function. A cell constitutes part of a base station. That is, each base station can have multiple cells. For example, there may be three cells for a single carrier frequency and associated bandwidth, each cell covering one-third of a 360-degree area, so that the coverage area of ​​a single base station covers an approximate ellipse or circle. In addition, each cell may correspond to a single carrier, and a base station may use multiple carriers. Therefore, if there are three 120-degree cells and two carriers per carrier, the base station has a total of 6 cells.

[0040] The wireless network 100 may include one or more network elements 190, which may include core network functions and provide connectivity to another network, such as a telephone network and / or a data communications network (e.g., the Internet), via one or more links 181. Such core network functions for 5G may include a location management function (LMF) and / or an access and mobility management function (AMF(S)) and / or a user plane function (UPF) and / or a session management function (SMF). Such core network functions for LTE may include MME (Mobility Management Entity) / SGW (Serving Gateway) functions. Such core network functions may include SON (Self-Organizing / Optimizing Network) functions. These are merely example functions that may be supported by the network element 190, and note that both 5G and LTE functions may be supported. The RAN node 170 is coupled to the network element 190 via a link 131. The link 131 may be implemented, for example, as an NG interface for 5G, or an S1 interface for LTE, or other suitable interfaces for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N / WI / F) 180 interconnected by one or more buses 185. The one or more memories 171 include computer program code 173. The computer program code 173 may include SON and / or MRO functionality 172.

[0041] The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functions into a single software-based management entity or virtual network. Network virtualization involves platform virtualization, which is usually combined with resource virtualization. Network virtualization is divided into external virtualization and internal virtualization. External virtualization combines many networks or parts of networks into virtual units, and internal virtualization provides network-like functions to software containers on a single system. Note that the virtualized entity produced by network virtualization is still implemented using hardware (e.g., processor 152 or 175 and memory 155 and 171) to some extent, and such virtualized entity also produces technical effects.

[0042] Computer readable memories 125, 155, and 171 may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, non-transitory memory, temporary memory, fixed memory, and removable memory. Computer readable memories 125, 155, and 171 may be components for performing storage functions. As non-limiting examples, processors 120, 152, and 175 may be of any type suitable for the local technical environment and may include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Processors 120, 152, and 175 may be components for performing functions, such as controlling UE 110, RAN node 170, network element 190, and other functions described herein.

[0043] In general, various example embodiments of the user equipment 110 may include, but are not limited to, a cellular phone (such as a smart phone), a tablet computer, a personal digital assistant (PDA) with wireless communication capabilities, a portable computer with wireless communication capabilities, an image capture device, such as a digital camera with wireless communication capabilities, a gaming device with wireless communication capabilities, a music storage and playback device with wireless communication capabilities, an Internet device (including a device that allows wireless Internet access and browsing), a tablet computer with wireless communication capabilities, a head-mounted display (such as a head-mounted display that implements virtual / augmented / mixed reality), and a portable unit or terminal that includes a combination of these functions. The UE 110 may also be a vehicle (such as a car) or a UE installed in a vehicle, a UAV (such as a drone) or a UE installed in a UAV. The user equipment 110 may be a terminal device such as a mobile phone, a mobile device, a sensor device, etc., which is a device used by a user or a device not used by a user.

[0044] UE 110, RAN node 170 and / or network element 190 (and associated memory, computer program code and modules) may be configured to (e.g., in part) implement the methods described in the present disclosure, including methods for obtaining multiple TRPs through TA. Thus, computer program code 123 of UE 110, module 140-1, module 140-2 and Figure 1 Other elements / features shown in the figure may implement the user equipment related aspects of the examples described in the present disclosure. Similarly, the computer program code 153, module 150-1, module 150-2 and Figure 1 The other elements / features shown in the figure may implement the exemplary gNB / TRP related aspects described in the present disclosure. The computer program code 173 of the network element 190 and Figure 1Other elements / features shown in the figure may be configured to implement the network element-related aspects of the examples described in this disclosure.

[0045] Having thus introduced a suitable but non-limiting technical background for practicing example embodiments, example embodiments are now described in more detail.

[0046] Examples described in this disclosure relate to methods for multiple TRPs through TA acquisition. In addition, examples described in this disclosure relate to early timing advance (TA) acquisition of candidate target cells for Rel-18 L1 / L2 triggered mobility (LTM).

[0047] Candidate cell and candidate target cell may be used interchangeably in this document. Serving cell and serving DU may be used interchangeably in this document. Layer 1 / 2 (L1 / 2) triggered mobility (LTM) is a term used by 3GPP RAN2 for lower layer (L1 / 2) mobility. Cell handover and cell transfer may be used interchangeably in this document.

[0048] L1 / L2 Triggered Mobility (LTM). LTM, also denoted as L1 / 2 inter-cell mobility, is one of the targets of mobility enhancement in Release 18. According to the example description, the decision on cell change is based on L1 measurements and is made in the MAC layer in the Distributed Unit (DU).

[0049] Figure 2 An exemplary message exchange for an inter-DU LTM scenario captured for a decomposed architecture is shown. Figure 2 The signaling message exchange in involves UE 110, source DU 210, target DU 220 and CU 230. In short:

[0050] The UE provides L3 measurements to the source DU, which are forwarded to the centralized unit (CU) (steps 1-2). Based on these measurements, the CU makes a decision about cell preparation (HO decision - step 3) and proceeds to establish the UE context in the target DU (steps 4-5). The CU communicates with the source DU to modify the UE context if needed and provide target cell information (i.e., target cell RS configuration, TCI status, etc.) (steps 6-7).

[0051] In step 8, the CU creates an RRC Reconfiguration message and uses DL RRC Message Transfer to forward the RRC Reconfiguration message to the source DU, which forwards the RRC Reconfiguration message to the UE (steps 9-10). If CU participation is required, the TA may be involved in obtaining the configuration. The UE responds to the CU with RRC ReconfigurationComplete (steps 11-12).

[0052] Based on its configuration, the UE provides periodic L1 reports to the source DU (step 13).

[0053] Based on the received L1 measurement report, the source DU can trigger the UE, for example, by sending a PDCCH command, to obtain the TA for the candidate cell set (i.e., the candidate cells of the handover target cell) (step 14-step 15). Regarding the mechanism for obtaining the TA of the candidate cell, in the additional RACH-based PDCCH command-based mechanism, additional solutions without RACH such as Rx timing difference, RACH-free mechanism such as LTE, SRS-based TA acquisition, etc. can be further studied.

[0054] During the LTM preparation phase (eg, steps 4-5), the source DU / CU and the candidate target DU / CU coordinate the TA acquisition method.

[0055] The UE continues L1 measurement reporting. Once the source DU decides that the UE should switch to the cell (i.e., the target cell) of another DU (i.e., the target DU), it triggers the cell switching using a cell switching command (e.g., MAC CE) (steps 16-18). In one solution, the cell switching command may also contain the TA of the target cell.

[0056] The UE then applies the RRC configuration of the target cell for the target DU indicated by the cell handover command (via MAC CE) and switches to the target DU. As shown in steps 19-20, the UE may be configured to perform random access (RA) on the target cell. However, in other solutions, the UE may be configured not to perform RA on the target cell because it has already acquired the TA of the target cell. To initiate communication with the target DU, the UE transmits an RRC Reconfiguration Complete to the target cell of the target DU using the configured UL resources, which is forwarded to the CU-CP (steps 21-22).

[0057] The CU releases the UE context from the source DU using UE Context Release Request and performs a path switch to the new DU (step 23-step 25).

[0058] Group-based beam reporting and multi-TRP operation

[0059] For multi-PDSCH transmission based on single DCI, the TCI code point in the DCI can correspond to 2 TCI states (up to 2 TRPs are supported in 3GPP). For a single DCI SDM PDSCH scheme, when the TCI code point indicates 2 TCI states and the indicated DMRS ports are from two CDM groups, the first TCI state and the second TCI state are applied to the indicated first CDM group and the indicated second CDM group, respectively. For a single DCI FDM / TDM PDSCH scheme, when the TCI code point indicates 2 TCI states and the corresponding FDM / TDM scheme is pre-configured, the first TCI state and the second TCI state are applied to the indicated first FD / TD resource allocation and the indicated second FD / TD resource allocation, respectively.

[0060] For multiple PDSCH transmission based on multiple DCIs, each DCI schedules its own PDSCH, where each PDSCH is transmitted from a separate TRP. For multiple PDSCH transmission based on multiple DCIs, if the UE is configured by the higher layer parameter PDCCH-Config containing two different values ​​of coresetPoolIndex in ControlResourceSet, the UE may expect to receive multiple PDCCHs scheduling full / partial / non-overlapping PDSCHs in both time and frequency domains.

[0061] To enable mTRP operation, for periodic and semi-persistent CSI resource settings, when the UE is configured with groupBasedBeamReporting-r17, the number of configured CSI Resource Sets is S=2, otherwise the number of configured CSI-RS resource sets is limited to S=1 [Section 5.2.1.2 in TS 38.214].

[0062] If the UE is configured with CSI-ReportConfig and the higher layer parameter reportQuantity is set to 'crib-RSRP', 'ssb-Index-RSRP', 'crib-RSRP-Capability[Set]Index' or 'ssb-Index-RSRP-Capability[Set]Index', and if the UE is configured with the higher layer parameter groupBasedBeamReporting-r17, the UE does not need to update measurements for more than 64 CSI-RS and / or SSB resources, and the UE shall report two groups of CRIs or SSBRIs in a single reporting instance nrofReportedRSgroup (if configured), selecting one CSI-RS or SSB from each of the two CSI resource sets for the reporting set, where each group of CSI-RS and / or SSB resources can be received simultaneously by the UE [Section 5.2.1.4.2 in TS 38.214].

[0063] Physical Downlink Control Channel (PDCCH) order details [Section 7.3.1.2.1, TS38.212]

[0064] Layer 1 Downlink Control Indication (DCI) format 1_0 is used to send PDCCH orders. The following information is transmitted via DCI format 1_0 with a CRC scrambled by the cell radio network temporary identifier (C-RNTI):

[0065] 1-bit identifier for DCI format. The value of this bit field is always set to 1, indicating a DL DCI format.

[0066] Frequency Domain Resource Allocation - bits, where if CORESET0 is configured for the cell, then is the size of the initial DL bandwidth portion for CORESET 0; otherwise, it is the size of the initial DL bandwidth portion. The value of this field is set to all 1s.

[0067] According to ra-PreambleIndex in clause 5.1.2 of [8, TS 38.321], random access preamble index - 6 bits. It indicates which random access preamble is used in case of contention-free random access (CFRA), or the value 000000 is used in case of contention-based random access (CBRA) procedure. If the preamble index bit is set to '0', the UE shall trigger a contention-based random access procedure, otherwise if the preamble index > 0, the UE shall trigger a contention-free random access procedure. A non-zero value is used to assign a dedicated Prach index (0 to 63) to the UE.

[0068] UL / SUL indicator - 1 bit. If the value of "Random Access Preamble Index" is not all zeros, and if the UE is configured with supplementaryUplink in ServingCellConfig in the cell, this field indicates which UL carrier in the cell transmits PRACH according to Table 7.3.1.1.1-1 in TS 38.212; otherwise, this field is reserved.

[0069] SS / PBCH Index - 6 bits. If the value of "Random Access Preamble Index" is not all zeros, this field indicates the SS / PBCH that should be used to determine the RACH opportunity for PRACH transmission; otherwise, this field is reserved.

[0070] PRACH Mask Index - 4 bits. If the value of "Random Access Preamble Index" is not all zeros, then according to clause 5.1.1 of [8, TS38.321], this field indicates the RACH opportunity associated with the SS / PBCH indicated by "SS / PBCH Index" for PRACH transmission; otherwise, this field is reserved.

[0071] Reserved bits - 12 bits are reserved for operating in cells with shared spectrum channel access in frequency range 1, or in cells in frequency range 2-2 when monitoring DCI formats in the common search space; otherwise, 10 bits.

[0072] In one example, the UE may obtain information to acquire multiple timing advances associated with each TRP of multiple TRPs. The examples described in the present disclosure relate to general interactions with low-layer triggered mobility, where TA acquisition performed for a candidate target cell is not covered. The examples described in the present disclosure address the issue of a serving DU determining a configuration for an sTRP or mTRP configuration that was not previously provided in the configuration. In addition, the examples described in the present disclosure include processing when TA acquisition using a TRP fails, and using the TA acquisition result to determine sTRP / mTRP operation.

[0073] In Rel-16, intra-cell multi-TRP (mTRP) downlink shared channel transmission was enabled to improve reliability and robustness in scenarios with ideal and non-ideal backhaul, which was also enhanced in Rel-17 for other downlink (PDCCH) and uplink channels (PUCCH, PUSCH) as well as inter-cell scenarios.

[0074] With Rel-18 LTM, one of the motivations, in addition to reducing the interruption time, is to maintain or even improve transmission efficiency and reliability during fast cell switching. In order to reduce the switching interruption time, the UE can be configured to perform early uplink (UL) synchronization, i.e., TA acquisition for one or more candidate cells (including the target cell) before the UE receives a cell switching command. This eliminates the need for UL synchronization with the target cell at the time of cell switching and thus reduces the interruption time.

[0075] The early TA acquisition process of LTM can be enhanced to multi-TA acquisition of multi-TRP to achieve a smooth transition to mTRP operation. However, the following issues (1-3) still need to be addressed:

[0076] 1. If mTRP operation is selected for a UE based on L1 measurement reports, and early timing advance acquisition for any TRP subsequently fails, the serving DU may continue to trigger timing advance acquisition in vain to enable RACH-free operation. This delays cell handover.

[0077] 2. If the target DU has configured single TRP (sTRP) operation as LTM configuration, but after some time, UE radio measurements may indicate that it can receive from both TRPs of the target cell. In this scenario, if the UE switches to the target DU with single TRP operation, the UE will have lower throughput even if high throughput is achievable if mTRP operation is configured. The main problem is that there is no mechanism to indicate the possible switch to mTRP operation to the target DU.

[0078] A similar problem statement can be formulated from a timing advance perspective. The UE may be configured for single TRP operation with LTM. The UE may obtain (e.g., for non-colocated carrier aggregation) the timing advance of the TRP of a cell that may be used for LTM for multi-TRP operation. Again, there is no mechanism to indicate a possible switch to an mTRP to the target DU.

[0079] The examples described in this disclosure relate to enhancements for LTM with multiple TRPs. This is achieved by enhancing the service DU behavior and service DU to CU signaling (1-2):

[0080] 1. Enhance the serving DU to monitor the possibility of configuring multiple TRPs for the UE when the UE was initially configured with only a single TRP configuration. This possibility is indicated by the CU to the DU. In one embodiment, the CU (in coordination with the target DU) provides the DU with information on the beam pairs (or PCIs or radio resource sets) that can be used for m-TRP operation. Therefore, by monitoring the received measurements, the DU can decide between s-TRP and m-TRP.

[0081] In one example, the DU may determine whether the UE may be configured with mTRP operation in the target cell based on the DL RS indicated by the TCI state and the received measurements.

[0082] 2. But on the contrary, if multiple TRPs are configured, the service DU is enhanced to monitor the possibility of initiating a single TRP instead of mTRP or multiple TRPs by triggering the RACH of one branch and accessing one branch without RACH.

[0083] The serving DU monitors the L1-RSRP measurements to indicate to the CU the possibility of a multi-TRP configuration and the TRPs (cells) involved. The DU monitors the result of the TA acquisition process (i.e., if the UE fails to acquire one TRP among multiple TRPs), the DU indicates to the CU that a single TRP configuration may be better for the UE.

[0084] Depending on UE capabilities, m-TRP operation may be constrained by the TA difference between two TRPs (TCI states). For example, if the TA difference between two TRPs is lower than the CP, the s-DU / CU may use the s-TRP configuration UE configuration.

[0085] In one example, the CU may provide the DU with a TAG ID association for one or more TCI states (which may be used to determine whether one or two TA values ​​or TA values ​​per TRP are required in mTRP operation). The DU may determine whether the UE can / should configure mTRP operation in the target cell based on the DL RS indicated by the TCI state and the received measurements.

[0086] In an additional embodiment, the UE may be configured with group based beam reporting (GBBR), and as part of the GBBR reporting, the DU may trigger TA acquisition (and later m-TRP operation) for the beam pairs reported by the UE.

[0087] Using this indication, the CU configures the UE with mTRP or sTRP operation. Or if the UE is already configured with mTRP and sTRP operation, the serving DU can implicitly / explicitly indicate the initiation of sTRP or mTRP operation on the UE side using the timing advance acquisition information.

[0088] In one embodiment, (for multiple TRPs with the same PCI), triggering of TA acquisition for two TCI states may implicitly indicate m-TRP operation to the UE. And triggering TA acquisition for one TCI state may imply s-TRP operation. Similarly can be applied to the target DU, where in case of receiving two TA RAs from one UE on two TCI states (RO), it means that the UE has met the m-TRP configuration / conditions.

[0089] In another embodiment, if the L1 / L3 measurement result is above a certain threshold, the UE is configured to apply the m-TRP configuration.

[0090] In one embodiment, the UE may be configured to indicate the stronger measured TRP (of the measured TRPs) to the target DU / CU, for example using a different preamble for the stronger TRP.

[0091] In one example, for implicit indication, if the cell switching command includes one TCI state (beam indication), the UE assumes single TRP operation, i.e., a single TRP configuration is applied upon cell switching.

[0092] In one example, for implicit indication, if the cell switching command includes two TCI states (beam indication), the UE assumes multi-TRP operation, that is, multi-TRP configuration is applied at the time of cell switching.

[0093] In another example, if the UE is (explicitly) indicated with mTRP operation, but the cell switch command includes a TCI state ID, the UE assumes mTRP operation, but applies the indicated TCI state to the mTRP operation, but assumes that a beam indication for a second TRP is received after the cell switch.

[0094] In case of direct TA value transmission (RAR) from target DU to UE, the RA response may include implicit / explicit indication for s-TRP / m-TRP operation. The UE may then indicate this to the CU or source-DU. Similarly, this information may also be provided to the source DU. Therefore, the UE does not need to report to the source DU.

[0095] Figure 3 , Figure 4 and Figure 5 Each shows a message sequence chart between UE 110, DU1 (source cell) 210, CU 230, DU 2TRP1 (candidate cell) 220-1 and DU 2TRP2 (candidate cell) 220-2 based on an example described in the present disclosure. DU 2 in some examples is a network node with two transmission reception points, namely TRP 1 and TRP 2, and DU 2 in some examples represents two network nodes, wherein the first network node of the two network nodes includes TRP 1, and the second network node of the two network nodes includes TRP 2.

[0096] Figure 3 is a message sequence chart used to trigger an sTRP operation or an mTRP operation in case of a retry on RACH.

[0097] UE 110 is configured with sTRP and mTRP operation for LTM (306, 308).

[0098] The target DU / CU provides early TA acquisition configuration for m-TRP and s-TRP operations (307).

[0099] DU triggers (210) TA acquisition (313) on two TRPs. The two TRPs have the same PCI and different PCIs. TA acquisition fails (316) on one TRP (220-2).

[0100] When the CU 230 transmits (317) only the TA of one TRP to the DU 210, the DU (210) knows that the TA acquisition fails.

[0101] DU 210 is configured by CU 230 or target DU, or determines itself (319, 326) to indicate sTRP operation (option 1318) or mTRP operation, with RACH-free operation on one TRP (220-1) and TA acquisition (option 2325) on another TRP (220-2). DU (210) indicates the triggering behavior to DU2 TRP1 (220-1) and TRP2 (220-2). As a result, resources for TRP2 (220-2) can be released, and TRP1 (220-1) can perform the required procedures, such as initiating monitoring of the first uplink resources from the UE side 110. Such an indication can be assumed by TRP 1 (220-1) or TRP 2 (220-2), i.e. once DU2220-1 indicates a timing advance of TRP1 (220-1) within a time period in which it can be assumed that an sTRP can be triggered.

[0102] like Figure 3 As further indicated in , at 322, DU 2TRP1 (candidate cell) 220-1 determines that the sTRP configuration for UE 110 will be used, and at 327, DU 210 sends a message to UE 110 to retry TA acquisition for TRP2P.

[0103] The indication (e.g., the indication sent at 327) to perform a cell handover with multiple transmission reception point operation while retrying to acquire a timing advance for a second candidate cell may be explicit or implicit. For example, in the case of an implicit indication, the beam indication associated with the first candidate cell (first TRP, e.g., DU2 TRP 1220-1) may have an associated TA given in the cell handover command, while the beam indication given for the second candidate cell (second TRP, e.g., DU 2TRP 2220-2) may not have any valid associated TA value given in the cell handover command, e.g., no value or a specific value indicating an invalid TA value.

[0104] Figure 4is a message sequence chart used to trigger mTRP configuration after UE measurement.

[0105] CU 230 configures sTRP operation for LTM for UE 110 (408). At 410, CU 230 indicates the mTRP configuration (mapping between RS (SSB / CSI-RS) and target DU TRP (e.g., 220-1, 220-2)) in terms of measurement reports to serving DU 210 to determine possible mTRP operations based on the measurement reports.

[0106] In the event that the UE report (413) indicates that multiple beams are being received simultaneously from multiple TRPs, at 414, the serving DU 210 determines that mTRP operation is possible. Conventional L1 measurements from a larger set of candidate cells (RSs from multiple TRPs) can be configured for LTM. There is no need to configure the measurement RSs of candidate cells for a UE for a specific neighboring cell; instead, for dynamic switching between sets of neighboring cells, a larger set (RSs from multiple TRPs) can be configured to apply to multiple neighboring cells. Traditional reporting can then be used, for example, a cell can send SSBs from different TRPs in a TDM manner and receive reports from the UE to discover whether the UE can hear different TRPs.

[0107] At 415, serving DU 210 sends an indication to CU 230, and CU 230 configures the UE for mTRP operation for LTM (418). Once UE 110 is configured, mTRP LTM may be triggered (424, 425) once the measurements are strong enough. Figure 4 It is also shown that DU1 (source cell) 210 monitors the mTRP Ready status at 412 .

[0108] Figure 5 is a message sequence chart used to trigger mTRP configuration after TA acquisition.

[0109] CU 230 configures sTRP operation for LTM for UE 110 (508). CU 230 indicates to serving DU 210 (eg, at 510) that it should monitor the timing advance of the TRP list to determine mTRP operation.

[0110] At 512, serving DU 210 starts monitoring the timing advance maintenance on the UE side. At 514, serving DU 210 instructs UE 110 to obtain timing advance from TRP 2 (220-2) for another operation, namely, carrier aggregation.

[0111] At 516, UE 110 reports successful timing advance acquisition.

[0112] At 517, the DU 210 determines that RACH-free switching to these TRPs is possible for mTRP operation.

[0113] At 518, serving DU 210 sends an indication to CU 230, and CU 230 configures (521) UE 110 for mTRP operation for LTM.

[0114] Once the UE 110 is configured, once the measurement is strong enough, the mTRP LTM may be triggered (525, 526).

[0115] The examples described herein may be standardized for Release 18 and are relevant to UEs supporting LTM.

[0116] Figure 6 An example apparatus 600 configured to implement the examples described in the present disclosure may be implemented in hardware. The apparatus 600 includes at least one processor 602 (e.g., an FPGA and / or a CPU), one or more memories 604 including computer program code 605 having instructions for executing the methods described in the present disclosure, wherein the at least one memory 604 and the computer program code 605 are configured to, together with the at least one processor 602, cause the apparatus 600 to implement circuits, processes, components, modules, or functions (implemented with a control module 606) for implementing the examples described in the present disclosure, including a method for acquiring multiple TRPs through TA. The memory 604 may be a non-transitory memory, a temporary memory, a volatile memory (e.g., a RAM), or a non-volatile memory (e.g., a ROM). The TA acquisition 630 and configuration / instruction 640 of the control module implement aspects of the present disclosure related to the method for acquiring multiple TRPs through TA.

[0117] The device 600 includes a display and / or I / O interface 608, which includes user interface (UI) circuits and elements that can be used to display aspects or states of the methods described in the present disclosure (e.g., while one of the methods is being executed or at a subsequent time), or to receive input from a user, such as using a keypad, camera, touch screen, touch area, microphone, biometrics, one or more sensors, etc. The communication I / F 610 can be wired and / or wireless and communicate via any communication technology (including via one or more links 624 over the Internet / other network). Links 624 can be from Figure 1 Links 131 and / or 176. Figure 1 The links 131 and / or 176 may also be implemented using the transceiver 616 and the corresponding wireless link 626. The communication I / F 610 may include one or more transmitters or one or more receivers.

[0118] The transceiver 616 includes one or more transmitters 618 and one or more receivers 620. The transceiver 616 and / or the communication I / F 610 may include standard well-known components such as amplifiers, filters, frequency converters, (de)modulators, and encoder / decoder circuits, and one or more antennas such as antenna 614 for communicating over a wireless link 626.

[0119] The control module 606 of the device 600 includes one or both of the parts 606-1 and / or 606-2, which can be implemented in a variety of ways. The control module 606 can be implemented in hardware as a control module 606-1, such as being implemented as a part of one or more processors 602. The control module 606-1 can also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, the control module 606 can be implemented as a control module 606-2, which is implemented as a computer program code (with corresponding instructions) 605 and is executed by one or more processors 602. For example, one or more memories 604 store instructions that, when executed by one or more processors 602, cause the device 600 to perform one or more operations as described herein. In addition, one or more processors 602, one or more memories 604, and example algorithms (e.g., as flow charts and / or signaling diagrams) encoded as instructions, programs, or codes are components for enabling the operation described in the present disclosure to be performed.

[0120] The device 600 implementing the function of the control 606 may be a UE 110, a RAN node 170 (e.g., a gNB), or a network element 190. Therefore, the processor 602 may correspond to the processor 120, the processor 152, and / or the processor 175, the memory 604 may correspond to one or more memories 125, one or more memories 155, and / or one or more memories 171, the computer program code 605 may correspond to the computer program code 123, the computer program code 153, and / or the computer program code 173, the control module 606 may correspond to the module 140-1, the module 140-2, the module 150-1, and / or the module 150-2, and the communication I / F 610 and / or the transceiver 616 may correspond to the transceiver 130, the antenna 128, the transceiver 160, the antenna 158, the N / WI / F 161, and / or the N / WI / F 180. Alternatively, the apparatus 600 and its elements may not correspond to any of the UE 110, the RAN node 170, or the network element(s) 190 and their respective elements, as the apparatus 600 may be part of a Self-Organizing / Optimizing Network (SON) node or other node, such as a node in the cloud.

[0121] The apparatus 600 may also correspond to the DU 1 (source cell) 210, the CU 230, the DU 2, the DU 2 TRP1 (candidate cell) 220-1, or the DU 2 TRP 2 (candidate cell) 220-2.

[0122] The apparatus 600 may also be distributed throughout a network (eg, 100 ), including within and between the apparatus 600 and any network elements (eg, a network control element (NCE) 190 and / or a RAN node 170 and / or a UE 110 ).

[0123] Interface 612 enables data communication and signaling between various items of apparatus 600, such as Figure 6 As shown. For example, interface 612 can be one or more buses, such as an address, data, or control bus, and can include any interconnect mechanism, such as a series of lines on a motherboard or integrated circuit, an optical fiber or other optical communication device, etc. The computer program code (e.g., instructions) 605 including control 606 can include object-oriented software that is configured to pass data or messages between objects within computer program code 605. Device 600 need not include each of the features mentioned, or may also include other features. The various components of device 600 may reside at least partially in a common housing 628, or a subset of the various components of device 600 may be at least partially located in a different housing, which may include housing 628.

[0124] Figure 7 Schematic representations of non-volatile memory media 700a (e.g., a computer / compact disk (CD) or digital versatile disk (DVD)) and 700b (e.g., a universal serial bus (USB) memory stick) and 700c (e.g., cloud storage for downloading instructions and / or parameters 702 or receiving instructions and / or parameters 702 sent by email) storing instructions and / or parameters 702 that, when executed by a processor, allow the processor to perform one or more steps of the methods described in the present disclosure.

[0125] Figure 8The present invention is an example method 800 based on an example embodiment described in the present disclosure. At 810, the method includes receiving an indication from a network node to monitor the possibility of configuring a user equipment for single transmission reception point operation, or receiving an indication from a network node to monitor the possibility of configuring a user equipment for multiple transmission reception point operation. At 820, the method includes determining whether it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation. At 830, the method includes transmitting to the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation. The method 800 can be performed by DU 1210, DU 195, RAN node 170, one or more network elements 190, or device 600.

[0126] Fig. 9 The present invention is an example method 900 based on an example embodiment described in the present disclosure. At 910, the method includes transmitting to a network node an indication for monitoring the possibility of configuring a user equipment for single transmission reception point operation, or transmitting to a network node an indication for monitoring the possibility of configuring a user equipment for multiple transmission reception point operation. At 920, the method includes receiving from a network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation. At 930, the method includes configuring the user equipment for single transmission reception point operation or multiple transmission reception point operation based on the indication received from the network node. The method 900 may be performed by a CU 230, a CU 196, a RAN node 170, one or more network elements 190, or an apparatus 600.

[0127] Fig.10 The present invention is an example method 1000 based on an example embodiment described in the present disclosure. At 1010, the method includes providing access to a first candidate cell and a second candidate cell. At 1020, the method includes performing at least one of the following: receiving an indication to configure a single transmission reception point operation for a user equipment when the user equipment has acquired a timing advance for the first candidate cell but failed to acquire a timing advance for the second candidate cell, or receiving an indication to configure a multi-transmission reception point operation for a user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell when the user equipment has acquired a timing advance for the first candidate cell but failed to acquire a timing advance for the second candidate cell. At 1030, the method includes performing a single transmission reception point operation or a multi-transmission reception point operation with the user equipment. The method 1000 may be performed by DU 2TRP 1220-1, DU 2TRP 2220-2, DU 195, RAN node 170, one or more network elements 190, or apparatus 600.

[0128] Fig.11The present invention is an example method 1100 based on an example embodiment described in the present disclosure. At 1110, the method includes receiving an indication to acquire a timing advance for a first candidate cell and a timing advance for a second candidate cell. At 1120, the method includes: in response to acquiring a timing advance for the first candidate cell but failing to acquire a timing advance for the second candidate cell, performing a single transmission reception point operation with the first candidate cell. At 1130, the method includes: in response to acquiring a timing advance for the first candidate cell but failing to acquire a timing advance for the second candidate cell, performing a multi-transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell. The method 1100 may be performed by the UE 110 or the device 600.

[0129] The following examples are provided and described herein.

[0130] Embodiment 1. An apparatus comprises: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, causes the apparatus to at least: receive an indication from a network node to monitor the possibility of configuring a user equipment for single transmission reception point operation, or receive an indication from a network node to monitor the possibility of configuring a user equipment for multiple transmission reception point operation; determine whether it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; and transmit to the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation.

[0131] Embodiment 2. An apparatus according to Example 1, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: configure the user equipment to obtain a timing advance for a first candidate cell and a timing advance for a second candidate cell; determine that the user equipment has obtained a timing advance for the first candidate cell but has failed to obtain a timing advance for the second candidate cell; and perform at least one of the following: indicate to the network node a single transmission reception point operation for the user equipment with the first candidate cell, or determine to configure the user equipment for a multiple transmission reception point operation with a random access channel with the second candidate cell and without a random access channel with the first candidate cell.

[0132] Embodiment 3. The apparatus according to Example 2, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: transmit to a user equipment a cell switching indication for performing cell switching using multiple transmission reception point operation while retrying to obtain a timing advance for a second candidate cell.

[0133] Embodiment 4. The apparatus according to Example 3, wherein the cell switching indication transmitted to the user equipment for performing cell switching using multiple transmission reception point operation while retrying to acquire the timing advance for the second candidate cell comprises an explicit indication or an implicit indication.

[0134] Embodiment 5. According to the apparatus of Example 4, when the beam indication associated with the second candidate cell does not include a valid timing advance value, the cell switching indication includes an implicit indication, wherein the beam indication associated with the second candidate cell is within the cell switching indication.

[0135] Embodiment 6. The apparatus according to Example 5, wherein the beam indication associated with the first candidate cell comprises a valid timing advance value, wherein the beam indication associated with the first candidate cell is within the cell handover indication.

[0136] Embodiment 7. The apparatus according to Example 6, wherein the first candidate cell is associated with a first transmission reception point, and the second candidate cell is associated with a second transmission reception point.

[0137] Embodiment 8. An apparatus according to any one of Examples 1 to 7, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: transmit an indication that a single transmission reception point operation is configured for a user equipment, or transmit an indication that a multiple transmission reception point operation is configured for a user equipment without a random access channel on a first candidate cell and with a random access channel on a second candidate cell.

[0138] Embodiment 9. The apparatus according to Example 8, wherein an indication that a single transmission reception point operation is configured for a user equipment, and an indication that a multiple transmission reception point operation is configured for a user equipment without a random access channel on a first candidate cell and with a random access channel on a second candidate cell, are transmitted to a network node or a distributed unit associated with the first candidate cell and the second candidate cell.

[0139] Embodiment 10 is an apparatus according to any one of Examples 8 to 9, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: receive an indication that a transmission is configured for a single transmission reception point operation for a user equipment, and transmit an indication that a configuration is configured for a user equipment for a multiple transmission reception point operation without a random access channel on a first candidate cell and with a random access channel on a second candidate cell.

[0140] Embodiment 11. The apparatus according to example 10, wherein the configuration is received from a network node or a distributed unit providing access to the first candidate cell and the second candidate cell.

[0141] Embodiment 12 is a device according to any one of Examples 1 to 11, wherein the instructions, when executed by at least one processor, cause the device to at least: receive an indication of successful timing advance acquisition from a user equipment; and based on the indication of successful timing advance acquisition, determine that a multi-transmission reception operation is possible for the user equipment; and indicate to a network node that a multi-transmission reception operation is possible for the user equipment.

[0142] Embodiment 13. An apparatus according to any one of Examples 1 to 12, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: receive a configuration for a measurement report related to multi-transmission reception point operation from a network node; receive at least one measurement from a user equipment; and determine whether it is possible to configure the user equipment for multi-transmission reception point operation based on the at least one measurement and the configuration for the measurement report.

[0143] Embodiment 14. The apparatus according to example 13, wherein the configuration for the measurement report comprises: a mapping between a reference signal and a target transmission reception point of the distributed unit.

[0144] Embodiment 15. An apparatus according to any one of Examples 13 to 14, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: receive an indication of reception of multiple beams from multiple transmission reception points from a user equipment based on at least one measurement; and determine that it is possible to configure the user equipment for multiple transmission reception point operation based on the indication of reception of multiple beams from multiple transmission reception points received from the user equipment.

[0145] Embodiment 16. The apparatus of any one of Examples 1-15, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: determine that a plurality of timing advances are available at the user equipment; and determine that because the plurality of timing advances are available at the user equipment, it is possible to configure the user equipment for multiple transmission reception point operations.

[0146] Embodiment 17. The apparatus according to any one of examples 1 to 16, wherein the apparatus comprises a distributed unit providing access to a source cell for a user equipment, and the network node comprises a central unit.

[0147] Embodiment 18. An apparatus comprises: at least one processor; and at least one memory storing instructions, wherein when the instructions are executed by the at least one processor, the apparatus at least: transmits to a network node an indication for monitoring the possibility of configuring a user device for single transmission reception point operation, or transmits to the network node an indication for monitoring the possibility of configuring a user device for multiple transmission reception point operation; receives from the network node an indication that it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation; and configures the user device for single transmission reception point operation or multiple transmission reception point operation based on the indication received from the network node.

[0148] Embodiment 19. The apparatus according to example 18, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: transmit to a network node an indication of monitoring whether the user equipment has acquired the timing advance for the first candidate cell and for the second candidate cell.

[0149] Embodiment 20. An apparatus according to any one of Examples 18 to 19, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: receive from a network node an indication of single transmission reception point operation of the user equipment with the first candidate cell when the user equipment has acquired the timing advance for the first candidate cell but has failed to acquire the timing advance for the second candidate cell, or receive from the network node an indication of multiple transmission reception point operation of the user equipment with the first candidate cell and the second candidate cell when the user equipment has acquired the timing advance for the first candidate cell but has not acquired the timing advance for the second candidate cell.

[0150] Embodiment 21. The apparatus according to Example 20, wherein the indication of the multi-transmission reception point operation for the user equipment indicates: configuring the multi-transmission reception point operation for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell.

[0151] Embodiment 22. An apparatus according to any one of Examples 18 to 21, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: transmit to a network node an indication for transmitting a configuration of a single transmission reception point operation for a user equipment, and a configuration for transmitting an indication for configuring a user equipment for a multiple transmission reception point operation without a random access channel on a first candidate cell and with a random access channel on a second candidate cell.

[0152] Embodiment 23. An apparatus according to any one of Examples 18 to 22, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: receive an indication from a network node that a multi-transmission reception operation may be used for a user equipment; and configure the user equipment for a multi-transmission reception point operation based on the received indication that the multi-transmission reception operation may be used for the user equipment.

[0153] Embodiment 24. An apparatus according to any one of Examples 18 to 23, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: transmit a configuration for measurement reporting related to multi-transmission reception point operation to a network node, wherein the configuration for measurement reporting is configured to determine whether multi-transmission reception point operation is possible for a user equipment.

[0154] Embodiment 25. The apparatus according to example 24, wherein the configuration for the measurement report comprises: a mapping between a reference signal and a target transmission reception point of the distributed unit.

[0155] Embodiment 26. The apparatus according to any one of Examples 18 to 25, wherein the apparatus comprises a central unit and the network nodes comprise distributed units.

[0156] Embodiment 27. A device, comprising: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, causes the device to at least: provide access to a first candidate cell and a second candidate cell; and perform at least one of the following: receive an indication to configure a single transmission reception point operation for a user equipment when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell, or receive an indication to configure a multiple transmission reception point operation for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell; and perform a single transmission reception point operation or a multiple transmission reception point operation with the user equipment.

[0157] Embodiment 28. The apparatus according to Example 27, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: release at least one resource associated with the second candidate cell.

[0158] Embodiment 29. An apparatus according to any one of Examples 27 to 28, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: transmit to a distributed unit associated with a source cell a configuration for performing at least one of the following: transmission of an indication for configuring a single transmission reception point operation for a user equipment, or transmission of an indication for configuring a multiple transmission reception point operation for a user equipment without a random access channel on a first candidate cell and with a random access channel on a second candidate cell.

[0159] Embodiment 30. The apparatus of any one of Examples 27 to 29, wherein the apparatus comprises a distributed unit having at least two transmission reception points.

[0160] Embodiment 31. An apparatus, comprising: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, causes the apparatus to at least: receive an instruction to acquire a timing advance for a first candidate cell and a timing advance for a second candidate cell; in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, perform a single transmission reception point operation with the first candidate cell; and in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, perform a multiple transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell.

[0161] Embodiment 32. The apparatus according to example 31, wherein the indication of obtaining the timing advance for the first candidate cell and the timing advance for the second candidate cell is received from a distributed unit providing access to the source cell for the user equipment.

[0162] Embodiment 33. The apparatus according to any one of Examples 31 to 32, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: receive a cell switching indication from a network for performing a cell switching using a multi-transmission reception point operation while retrying to obtain a timing advance for a second candidate cell.

[0163] Embodiment 34. The apparatus according to Example 33, wherein the cell switching indication received from the network to perform cell switching using multiple transmission reception point operation while retrying to acquire the timing advance for the second candidate cell comprises an explicit indication or an implicit indication.

[0164] Embodiment 35. The apparatus according to Example 34, wherein when the beam indication associated with the second candidate cell does not include a valid timing advance value, the cell switching indication comprises an implicit indication, wherein the beam indication associated with the second candidate cell is within the cell switching indication.

[0165] Embodiment 36. The apparatus of Example 35, wherein the beam indication associated with the first candidate cell comprises a valid timing advance value, wherein the beam indication associated with the first candidate cell is within the cell handover indication.

[0166] Embodiment 37. The apparatus of Example 36, wherein the first candidate cell is associated with a first transmission reception point and the second candidate cell is associated with a second transmission reception point.

[0167] Embodiment 38. An apparatus according to any one of Examples 31 to 37, wherein the instructions, when executed by at least one processor, cause the apparatus to at least: switch from a source cell to at least one of a first candidate cell or a second candidate cell in response to obtaining at least one of the following: a timing advance for the first candidate cell, or a timing advance for the second candidate cell, or a cell change command indicating a retry of a random access channel process to perform a multi-transmission reception point operation.

[0168] Embodiment 39. The apparatus of any one of Examples 31 to 38, wherein the apparatus comprises a user equipment.

[0169] Embodiment 40. A method, comprising: receiving an indication from a network node to monitor the possibility of configuring a user equipment for single transmission reception point operation, or receiving an indication from a network node to monitor the possibility of configuring a user equipment for multiple transmission reception point operation; determining whether it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; and transmitting to the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation.

[0170] Embodiment 41. A method, comprising: transmitting to a network node an indication for monitoring the possibility of configuring a user equipment for single transmission reception point operation, or transmitting to a network node an indication for monitoring the possibility of configuring a user equipment for multiple transmission reception point operation; receiving from the network node an indication that it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; and configuring the user equipment for single transmission reception point operation or multiple transmission reception point operation based on the indication received from the network node.

[0171] Embodiment 42. A method, comprising: providing access to a first candidate cell and a second candidate cell; and performing at least one of the following: receiving an indication to configure a single transmission reception point operation for a user equipment when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell, or receiving an indication to configure a multiple transmission reception point operation for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell; and performing a single transmission reception point operation or a multiple transmission reception point operation with the user equipment.

[0172] Embodiment 43. A method, comprising: receiving an indication for acquiring a timing advance for a first candidate cell and a timing advance for a second candidate cell; in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performing a single transmission reception point operation with the first candidate cell; and in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performing a multiple transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell.

[0173] Embodiment 44. An apparatus, comprising: a component for receiving an indication from a network node to monitor the possibility of configuring a user device for single transmission reception point operation, or receiving an indication from a network node to monitor the possibility of configuring a user device for multiple transmission reception point operation; a component for determining whether it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation; and a component for transmitting to the network node an indication that it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation.

[0174] Embodiment 45. An apparatus, comprising: a component for transmitting to a network node an indication for monitoring the possibility of configuring a user device for single transmission reception point operation, or transmitting to a network node an indication for monitoring the possibility of configuring a user device for multiple transmission reception point operation; a component for receiving from the network node an indication that it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation; and a component for configuring the user device for single transmission reception point operation or multiple transmission reception point operation based on the indication received from the network node.

[0175] Embodiment 46. An apparatus, comprising: a component for providing access to a first candidate cell and a second candidate cell; and a component for performing at least one of the following: receiving an indication for configuring a single transmission reception point operation for a user equipment when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell, or receiving an indication for configuring a multiple transmission reception point operation for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell when the user equipment has acquired a timing advance for the first candidate cell but has failed to acquire a timing advance for the second candidate cell; and a component for performing a single transmission reception point operation or a multiple transmission reception point operation with the user equipment.

[0176] Embodiment 47. An apparatus, comprising: a component for receiving an indication for acquiring a timing advance for a first candidate cell and a timing advance for a second candidate cell; a component for performing a single transmission reception point operation with the first candidate cell in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell; and a component for performing a multiple transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell.

[0177] Embodiment 48. A machine-readable, non-transitory program storage device tangibly embodying a program of instructions executable by the machine for performing operations, the operations comprising: receiving an indication from a network node to monitor the possibility of configuring a user device for single transmission reception point operation, or receiving an indication from a network node to monitor the possibility of configuring a user device for multiple transmission reception point operation; determining whether it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation; and transmitting to the network node an indication that it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation.

[0178] Embodiment 49. A machine-readable, non-transitory program storage device tangibly embodying a machine-executable program of instructions for performing operations, the operations comprising: transmitting to a network node an indication to monitor the possibility of configuring a user device for single transmission reception point operation, or transmitting to a network node an indication to monitor the possibility of configuring a user device for multiple transmission reception point operation; receiving from the network node an indication that it is possible to configure the user device for single transmission reception point operation or multiple transmission reception point operation; and configuring the user device for single transmission reception point operation or multiple transmission reception point operation based on the indication received from the network node.

[0179] Embodiment 50. A machine-readable non-transitory program storage device tangibly embodies a machine-executable instruction program for performing operations, the operations comprising: providing access to a first candidate cell and a second candidate cell; and performing at least one of the following: receiving an indication to configure a single transmission reception point operation for a user equipment when the user equipment has acquired a timing advance for the first candidate cell but failed to acquire a timing advance for the second candidate cell, or receiving an indication to configure a multiple transmission reception point operation for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell when the user equipment has acquired a timing advance for the first candidate cell but failed to acquire a timing advance for the second candidate cell; and performing a single transmission reception point operation or a multiple transmission reception point operation with the user equipment.

[0180] Embodiment 51. A machine-readable, non-transitory program storage device tangibly embodying a program of instructions executable by the machine for performing operations, the operations comprising: receiving an indication to acquire a timing advance for a first candidate cell and a timing advance for a second candidate cell; in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performing a single transmission reception point operation with the first candidate cell; and in response to acquiring the timing advance for the first candidate cell but failing to acquire the timing advance for the second candidate cell, performing a multiple transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell.

[0181] References to "computers", "processors", etc. should be understood to cover not only computers with different architectures (such as single / multi-processor architectures and sequential or parallel architectures), but also special-purpose circuits (such as field programmable gate arrays (FPGAs), application-specific circuits (ASICs), signal processing devices and other processing circuits). References to computer programs, instructions, code, etc. should be understood to cover software for programmable processors or firmware, such as, for example, the programmable content of hardware devices, whether instructions for a processor or configuration settings for a fixed-function device, gate array or programmable logic device, etc.

[0182] Memory as used herein may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, non-transitory memory, temporary memory, fixed memory, and removable memory. The memory may include a database for storing data.

[0183] As used herein, the term "circuitry" may refer to the following: (a) a hardware circuit implementation, such as an implementation in analog and / or digital circuits, and (b) a combination of circuitry and software (and / or firmware), such as (where applicable): (i) a combination of processors or (ii) portions of processors / software, including digital signal processors, software, and memory that work together to enable the device to perform various functions, and (c) circuitry, such as a microprocessor or a portion of a microprocessor, that requires software or firmware to operate, even if the software or firmware is not physically present. As another example, as used herein, the term "circuitry" would also cover an implementation of only a processor (or multiple processors) or a portion of a processor and its (or its) accompanying software and / or firmware. The term "circuitry" would also cover, for example and if applicable to the particular element, a baseband integrated circuit or an application processor integrated circuit for a mobile phone or a similar integrated circuit in a server, cellular network device, or another network device.

[0184] It should be understood that the foregoing description is illustrative only. Various alternatives and modifications may be devised by those skilled in the art. For example, the features described in the various dependent claims may be combined with each other in any suitable combination. In addition, features from the different example embodiments described above may be selectively combined into new example embodiments. Therefore, this specification is intended to cover all such alternatives, modifications and variations that fall within the scope of the appended claims.

[0185] The following acronyms and abbreviations that may be found in the specification and / or drawings are as follows (abbreviations and acronyms may be appended to each other or to other characters, such as using dashes, hyphens, slashes or numbers, and may not be case sensitive): 3GPP Third Generation Partnership Project 4G Fourth Generation 5G Fifth Generation 5GC 5G Core Network AMF Access and Mobility Management Function ASIC Application-Specific Integrated Circuit BWP Bandwidth Part CA Carrier Aggregation CBRA Contention-based random access CD / Computer CD CDM Code Domain Multiplexing CE Control Unit CFRA Contention-free random access CORESET Control Resource Set CP Cyclic Prefix CPU Central Processing Unit CRC Cyclic Redundancy Check CRI CSI-RS resource indicator C-RNTI Cell Radio Network Temporary Identifier CSI Channel State Information CSI-RS Channel State Information Reference Signal CU Central Unit or Centralized Unit DCI Downlink Control Information DL Downlink DMRS Demodulation Reference Signal DSP Digital Signal Processor DU Distributed Unit DVD Digital Versatile Disc eNB Evolved Node (e.g. LTE base station) EN-DC E-UTRAN New Radio - Dual Connectivity en-gNB is a node that provides NR user plane and control plane protocol termination to the UE and acts as a secondary node in EN-DC E-UTRA Evolved Universal Terrestrial Radio Access, also known as LTE radio access technology F1 Interface between CU and DU FD Frequency Division FDM frequency domain multiplexing FPGA Field Programmable Gate Array GBBR Group-based beam reporting gNB 5G / NR base station, i.e. the node that provides NR user plane and control plane protocol terminals to UE and is connected to 5GC through NG interface HO Handover IAB Integrated Access and Backhaul ID Identifier I / F Interface I / O Input / Output L1 Layer 1 L1 / 2 Layer 1 and / or Layer 2 L3 Layer 3 LMF Location Management Function LTE Long Term Evolution (4G) LTM Layer 1 / 2 Triggered Mobility MAC Media Access Control MME Mobility Management Entity MRO Mobility Robustness Optimization mTRP Multi-TRP NCE Network Control Unit Ng or NG New Generation ng-eNB Next Generation eNB NG-RAN Next Generation Radio Access Network nr number NR New Radio N / W Network OFDM Orthogonal Frequency Division Multiplexing PBCH Physical Broadcast Channel PCI Physical layer cell ID PDA Personal Digital Assistant PDCCH Physical Downlink Control Channel PDCP Packet Data Convergence Protocol PDSCH Physical Downlink Shared Channel PHY Physical Layer PRACH Physical Random Access Channel PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel R - Release RA Random Access RACH Random Access Channel RAM Random Access Memory RAN Radio Access Network RAN2 Radio Layer 2 RAR Random Access Response RB Resource Block RE Resource Element Rel Release RLC Radio Link Control RO RACH Timing ROM Read Only Memory RRC Radio Resource Control RS reference signal RSRP Reference Signal Received Power RU Wireless Unit Rx Receiver or Receiver SDAP Service Data Adaptation Protocol SDM Spatial Domain Multiplexing SGW Service Gateway SMF session management functions SON self-organizing / optimizing network SRS Sounding Reference Signal SS Sync Signal SSB sync signal and PBCH block, or synchronization signal block SSBRI SS / PBCH block resource indicator sTRP Single TRP SUL Supplementary Uplink TA Timing Advance TAG Timing Advance Group TCI Transmission Configuration Indicator TD Hours and Minutes TDM Time Domain Multiplexing TRP Transmission Reception Point TS Technical Specifications Tx, TX transmitter or transmission UAV UE User Equipment (e.g., wireless, typically mobile device) UI UL Uplink UPF User Plane Function USB Universal Serial Bus X2 Network interface between RAN nodes and between RAN and core network Xn Network interface between NG-RAN nodes

Claims

1. A device comprising: at least one processor; as well as at least one memory storing instructions, which, when executed by the at least one processor, cause the apparatus to at least: receiving an indication from a network node to monitor the possibility of configuring a user equipment for single transmission reception point operation, or receiving an indication from the network node to monitor the possibility of configuring the user equipment for multiple transmission reception point operation; determining whether it is possible to configure the user equipment for single transmission reception point operation or multiple transmission reception point operation; as well as An indication is transmitted to the network node that the user equipment may be configured for single transmission reception point operation or multiple transmission reception point operation.

2. The apparatus of claim 1 , wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: configuring the user equipment to obtain a timing advance for a first candidate cell and a timing advance for a second candidate cell; determining that the user equipment has acquired the timing advance for the first candidate cell but has failed to acquire the timing advance for the second candidate cell; Do at least one of the following: indicating to the network node a single transmission reception point operation for the user equipment and the first candidate cell, or Determine to configure the user equipment for multiple transmission reception point operation having a random access channel with the second candidate cell and not having a random access channel with the first candidate cell.

3. The apparatus of claim 2, wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: A cell switching indication is transmitted to the user equipment for performing a cell switching using a multi-transmission reception point operation while retrying to acquire the timing advance for the second candidate cell.

4. The apparatus according to claim 3, wherein the cell switching indication transmitted to the user equipment for performing the cell switching using multi-transmission reception point operation while retrying to obtain the timing advance for the second candidate cell comprises an explicit indication or an implicit indication.

5. The apparatus of claim 4, wherein the cell switching indication comprises the implicit indication when the beam indication associated with the second candidate cell does not include a valid timing advance value, wherein the beam indication associated with the second candidate cell is within the cell switching indication.

6. The apparatus of claim 5, wherein the beam indication associated with the first candidate cell comprises a valid timing advance value, wherein the beam indication associated with the first candidate cell is within the cell handover indication.

7. The apparatus of claim 6, wherein the first candidate cell is associated with a first transmission reception point and the second candidate cell is associated with a second transmission reception point.

8. The apparatus of any one of claims 1 to 7, wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: transmitting an indication that a single transmission reception point operation is configured for the user equipment; or An indication is transmitted that the user equipment is configured for multiple transmission reception point operation without a random access channel on a first candidate cell and with a random access channel on a second candidate cell.

9. The apparatus of claim 8, wherein the indication that the user equipment is configured with a single transmission reception point operation, and the indication that the user equipment is configured with a multiple transmission reception point operation without a random access channel on the first candidate cell and with a random access channel on the second candidate cell, are transmitted to the network node or a distributed unit associated with the first candidate cell and the second candidate cell.

10. The apparatus of claim 8, wherein the instructions, when executed by the at least one processor, cause the apparatus to at least: receiving a transmission indicating that a single transmission reception point operation is configured for the user equipment, and transmitting a configuration indicating that a multiple transmission reception point operation is configured for the user equipment without a random access channel on the first candidate cell and with a random access channel on the second candidate cell.

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