Multi-Cell SRS Updating in RRC Inactive State Under TA Validity
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately and efficiently transmitting and receiving signals, particularly in RRC inactive states due to timing advance (TA) validity issues, which affect the performance of sounding reference signals (SRS) for positioning.
Innovation Solution
A method and device for transmitting and receiving SRS in a wireless communication system, allowing SRS transmission and update procedures in RRC inactive states by maintaining the RRC inactive state without returning to the connected state, using SRS configuration supporting multiple cells and performing update procedures based on TA validity, with conditions for stopping or continuing SRS transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE returns to RRC connected state to update SRS configuration when TA becomes invalid, then the SRS transmission can be updated, but the signaling overhead and power consumption increase
Solution Approach 1:
The patent extracts the SRS configuration update procedure from the RRC connected state and enables it to be performed independently in the RRC inactive state through a simplified update mechanism, avoiding the need for full RRC connection establishment
Solution Approach 2:
The UE is configured with SRS parameters in advance while in RRC inactive state, allowing it to transmit SRS immediately when TA is valid without needing to transition to connected state first
2Measurement precision
If the UE transmits SRS in RRC inactive state with multiple cell configuration, then positioning accuracy improves, but the TA validity management becomes more complex
Solution Approach 1:
The patent segments the TA validity determination into separate conditions: a first condition for single cell case and a second condition for multi-cell case, allowing independent evaluation and simplifying the overall management complexity
Solution Approach 2:
The patent introduces specific parameters (timeAlignmentTimer, inactivePosSRS-RSRP-ChangeThreshold) to automatically manage TA validity in multi-cell scenarios, transforming the complex judgment into parameter-based automated control
3Reliability
If the UE stops SRS transmission when TA is invalid, then transmission errors are avoided, but positioning continuity is disrupted
Solution Approach 1:
The patent implements dynamic SRS transmission control where the UE adapts its transmission behavior based on real-time TA validity status and configured conditions, switching between transmission and update procedures as needed
Solution Approach 2:
The UE continuously monitors TA validity and provides feedback to control the SRS transmission state, automatically transitioning between transmission and update modes based on the monitored TA status
Data Source
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AI summary
According to at least one of the embodiments disclosed in the present specification, a method of transmitting a sounding reference signal (SRS) by a user equipment (UE) in a wireless communication system includes: receiving an SRS configuration supporting multiple cells for positioning in a radio resource control (RRC) inactive state; transmitting an SRS in the RRC inactive state based on the SRS configuration supporting the multiple cells while a timing advance (TA) is valid; and performing an update procedure for the SRS configuration supporting the multiple cells based on that the TA is no longer valid. The UE may perform the update procedure while maintaining the RRC inactive state.