EP-4742757-A1 - TIMING ADVANCE PROVISIONING FOR CONDITIONAL CELL SWITCH EXECUTION

Abstract

A method performed by a user equipment (UE) is provided. The method includes receiving, from a source cell, an order for early timing advance (TA) acquisition for at least one candidate cell indicated in the order. The method includes making a determination that the at least one candidate cell is at least one conditional lower-layer triggered mobility (CLTM) candidate cell. The method includes monitoring for at least one TA value for the at least one CLTM candidate cell based on the determination. And the method includes receiving the at least one TA value.

Inventors

• KAKKAVAS, Anastasios
• GOYAL, SANJAY
• GÜRSU, HALIT MURAT
• SPAPIS, Panagiotis
• ASHRAF, Shehzad Ali
• PALKA, Dariusz

Assignees

• Nokia Technologies Oy

Dates

Publication Date

20260513

Application Date

20251022

Claims (15)

1. An apparatus to implement a user equipment,UE, the apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: receive, from a source cell, an order for early timing advance, TA, acquisition for at least one candidate cell indicated in the order; make a determination that the at least one candidate cell is at least one conditional lower-layer triggered mobility, CLTM, candidate cell; monitor for at least one TA value for the at least one CLTM candidate cell based on the determination; and receive the at least one TA value.
2. The apparatus of claim 1, wherein the order includes an indication for the UE to monitor for the at least one TA value.
3. The apparatus of claim 1 or claim 2, wherein the at least one processing circuitry is configured to execute the instructions to cause the apparatus to further transmit a random access, RA,preamble to the at least one CLTM candidate cell to signal the at least one CLTM candidate cell to determine the at least one TA value which is transferred to the source cell, and wherein the apparatus caused to receive the at least one TA value includes the apparatus caused to receive TA information from the source cell that includes the at least one TA value.
4. The apparatus of any of claims 1 to 3, wherein the at least one processing circuitry is configured to execute the instructions to cause the apparatus to further transmit a random access, RA, preamble to the at least one CLTM candidate cell to signal the at least one CLTM candidate cell to determine the at least one TA value, and wherein the apparatus caused to receive the at least one TA value includes the apparatus caused to receive a random access response, RAR, from the at least one CLTM candidate cell that includes the at least one TA value.
5. The apparatus of any of claims 1 to 4, wherein the determination is made that each candidate cell of the at least one candidate cell indicated in the order is a current CLTM candidate cell.
6. The apparatus of claim 5, wherein the determination is made that the UE is configured with at least one condition for a conditional LTM cell switch from the source cell to the candidate cell, and that the candidate cell is controlled by a radio access node that also controls the source cell.
7. The apparatus of any of claims 1 to 6, wherein the determination is made that each candidate cell of the at least one candidate cell is a current CLTM candidate cell or a subsequent CLTM candidate cell.
8. The apparatus of claim 7, wherein the determination is made that the UE is configured with at least one condition for a conditional LTM cell switch from the source cell or another cell to the candidate cell.
9. The apparatus of any of claims 1 to 8, wherein the UE is configured to monitor for at least one TA value for only current CLTM candidate cells, or for both current CLTM candidate cells and subsequent CLTM candidate cells.
10. An apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: send, to a user equipment, UE, an order for early timing advance, TA, acquisition for at least one candidate cell indicated in the order; receive at least one TA value for the at least one candidate cell; make a determination that the at least one candidate cell is at least one conditional lower-layer triggered mobility, CLTM, candidate cell; and send the at least one TA value for the at least one CLTM candidate cell to the UE based on the determination.
11. The apparatus of claim 10, wherein the determination is made that each candidate cell of the at least one candidate cell indicated in the order is a current CLTM candidate cell.
12. The apparatus of claim 11, wherein the at least one processing circuitry is configured to execute the instructions to cause the apparatus to further receive information that indicates the UE is configured with at least one condition for a conditional LTM cell switch from the source cell to the candidate cell, and that the candidate cell is controlled by a radio access node that also controls the source cell, and wherein the determination is made based on the information.
13. The apparatus of claim 12, wherein the radio access node includes a centralized unit (CU) that controls a source DU supporting the source cell, and a candidate distributed unit (DU) supporting the candidate cell, and wherein the apparatus is to implement the source DU, and the information is received by the source DU from the CU.
14. The apparatus of any of claims 10 to 13, wherein the determination is made that each candidate cell of the at least one candidate cell is a current CLTM candidate cell or a subsequent CLTM candidate cell.
15. An apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: receive a random access, RA, preamble from a user equipment, UE, for an early timing advance,TA, acquisition for at least one candidate cell; determine at least one TA value for the at least one candidate cell; make a determination that the at least one candidate cell is at least one conditional lower-layer triggered mobility, CLTM, candidate cell; and send a random access response, RAR, including the at least one TA value for the at least one CLTM candidate cell to the UE based on the determination.

Description

TECHNOLOGICAL FIELD The present disclosure relates generally to telecommunications and, in particular, to conditional cell switch in a telecommunications system. BACKGROUND A telecommunications system can be seen as a facility that enables communication sessions between two or more entities such as user terminals, base stations and/or other nodes by providing carriers between the various entities involved in the communications path. A telecommunications system can be provided for example by means of a communication network and one or more compatible communication devices. The communication sessions may comprise, for example, communication of data for carrying communications such as voice, video, electronic mail (email), text message, multimedia and/or content data and so on. Non-limiting examples of services provided comprise two-way or multi-way calls, data communication or multimedia services and access to a data network system, such as the Internet. In a wireless telecommunications system, at least a part of a communication session between at least two stations occurs over a wireless link. Examples of wireless telecommunications systems comprise public land mobile networks (PLMN), satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). Some wireless systems can be divided into cells, and are therefore often referred to as cellular systems. A user can access the telecommunications system by means of an appropriate communication device or terminal. A communication device of a user may be referred to as user equipment (UE) or user device. A communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly with other users. The communication device may access a carrier provided by a station, for example a base station of a cell, and transmit and/or receive communications on the carrier. The telecommunications system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the communication system are permitted to do and how operations should be achieved. Communication protocols and/or parameters which shall be used for connection of the various entities are also typically defined. One example of a telecommunications system is the Universal Mobile Telecommunications System (UMTS). Other examples of telecommunications systems are Long-Term Evolution (LTE), LTE Advanced and the so-called 5G or New Radio (NR) networks. NR is being standardized by the 3rd Generation Partnership Project (3GPP). BRIEF SUMMARY Example implementations of the present disclosure are directed to telecommunications and, in particular, to conditional cell switch in a telecommunications system. The present disclosure includes, without limitation, the following example implementations. Some example implementations provide an apparatus to implement a user equipment (UE), the apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: receive, from a source cell, an order for early timing advance (TA) acquisition for at least one candidate cell indicated in the order; make a determination that the at least one candidate cell is at least one conditional lower-layer triggered mobility (CLTM) candidate cell; monitor for at least one TA value for the at least one CLTM candidate cell based on the determination; and receive the at least one TA value. Some example implementations provide a method performed by a user equipment (UE), the method comprising: receiving, from a source cell, an order for early timing advance (TA) acquisition for at least one candidate cell indicated in the order; making a determination that the at least one candidate cell is at least one conditional lower-layer triggered mobility (CLTM) candidate cell; monitoring for at least one TA value for the at least one CLTM candidate cell based on the determination; and receiving the at least one TA value. Some example implementations provide an apparatus comprising: at least one memory configured to store instructions; and at least one processing circuitry configured to access the at least one memory, and execute the instructions to cause the apparatus to at least: send, to a user equipment (UE), an order for early timing advance (TA) acquisition for at least one candidate cell indicated in the order; receive at least one TA value for the at least one candidate cell; make a determination that the at least one candidate cell is at least one conditional lower-layer triggered mobility (CLTM) candidate cell; and send the at least one TA value for the at least one CLTM candidate cell to the UE based on the determination. Som