UE TCI State Pre-configuration for Seamless Inter-cell Handover
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Solution Overview
Problem
In wireless communication systems, especially in the New Radio (NR) system, beam-based communications introduce negative impacts such as extra time delay and ping-pong effects during inter-cell handover, which need to be mitigated to meet the requirements of Ultra-Reliable and Low Latency Communications (URLLC) scenarios.
Innovation Solution
The method involves configuring reference signals from neighbor cells in the Transmission Configuration Indication (TCI) list, allowing seamless handover among beams in different serving cells, with the User Equipment (UE) assuming Quasi Co-Located (QCL) antenna ports, thereby avoiding time delays and service interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming is used to improve communication quality, then communication quality is improved, but inter-cell handover experiences extra time delay and ping-pong effects
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple TCI states including neighbor cell reference signals in the UE before handover is needed. This allows the UE to have beam information ready in advance, eliminating the need for time-consuming beam alignment during actual handover execution, thus resolving the time delay issue while maintaining beamforming communication quality
2Reliability
If beamforming is used to improve communication quality, then communication quality is improved, but handover experiences ping-pong effects
Solution Approach 1:
By pre-configuring multiple TCI states with neighbor cell reference signals, the UE maintains stable beam information across cell boundaries. This preliminary preparation prevents the instability and ping-pong effects that would otherwise occur during handover, as the UE can seamlessly switch between pre-configured beams without re-evaluation delays
Solution Approach 2:
The patent ensures continuity of useful action by maintaining beamforming capability across cell boundaries through pre-configured TCI states. The UE continues to use optimized beamforming without interruption or re-alignment during handover, eliminating the discontinuity that causes ping-pong effects while preserving communication quality
3Ease of operation
If reference signals from neighbor cells are configured in TCI list to enable seamless handover, then handover transparency is achieved, but implementation complexity increases
Solution Approach 1:
The patent applies self-service by enabling the UE to autonomously select and switch between pre-configured TCI states based on downlink signal quality measurements. The UE independently manages beam selection without requiring complex network coordination during handover, achieving transparent handover while limiting complexity growth to only the initial configuration phase
Data Source
AI summary
The present disclosure provides a method and a device in a User Equipment (UE) and a base station used for wireless communications. The UE receives first information; determines first sub-information out of the M piece(s) of sub-information; receives a first radio signal in a first time-frequency resource set; the first information comprises the M piece(s) of sub-information, each of the M piece(s) of sub-information indicates a reference signal group, and a reference signal group comprises at least one reference signal. The first sub-information indicates a first reference signal group. A reference signal in a reference signal group indicated by at least one of the M piece(s) of sub-information is transmitted by a first serving cell, and the first serving cell is not added by the UE. The above method not only obtains performance advancement brought by serving cell handover, but also avoid time delay and service interrupt.