Aperiodic SRS Resource Set Collision Handling
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Solution Overview
Problem
Collisions between aperiodic SRS resource sets in wireless communication systems lead to ambiguity and performance degradation, particularly in NR Rel-17, due to dynamic triggering and changing TDD slot formats, which affect power setting and channel estimation.
Innovation Solution
Implementing priority rules to define user equipment (UE) behavior for colliding SRS resource sets, such as dropping sets based on resource set identifiers, usage types, or number of resources, to ensure collision-free transmission and correct power control settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple aperiodic SRS resource sets are dynamically triggered, then channel estimation accuracy and link adaptation performance are improved, but resource set collisions occur leading to ambiguity and performance degradation
Solution Approach 1:
The patent changes the parameter of SRS resource set identification by introducing a new indicator field in DCI format 0_1 that directly indicates the SRS resource set ID. This parameter change eliminates the ambiguity caused by collision between multiple aperiodic SRS resource sets by providing explicit identification rather than relying on implicit collision resolution mechanisms.
2Loss of time
If aperiodic SRS transmission is dynamically activated via DCI, then transmission latency is reduced, but collision handling complexity increases due to changing TDD slot formats
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple aperiodic SRS resource sets with different slot offsets and uplink channel access types during RRC setup. When dynamic triggering occurs, the UE can immediately select the appropriate pre-configured resource set based on the DCI indicator without complex real-time collision analysis, thus reducing both latency and handling complexity.
Solution Approach 2:
The patent introduces an intermediary indicator field in DCI format 0_1 that serves as a mediator between the gNB's triggering decision and the UE's resource selection. This intermediary explicitly indicates which SRS resource set should be transmitted, simplifying the collision handling logic at the UE by replacing complex collision detection and resolution algorithms with a straightforward indicator-based selection.
3Adaptability or versatility
If SRS resource sets are configured with different slot offsets, then flexibility in resource allocation is improved, but determination of available slots becomes ambiguous when formats change
Solution Approach 1:
The patent changes the operational parameter by introducing a new uplink channel access type parameter that can be independently configured for each SRS resource set. This allows the system to maintain different slot offsets for flexibility while using the channel access type indicator to disambiguate which resource set is active, simplifying the determination of available slots by providing an explicit selection criterion rather than relying solely on slot format analysis.
Data Source
AI summary
According to some embodiments, a method performed by a wireless device for transmitting a sounding reference signal (SRS) comprises: receiving a SRS configuration for two or more SRS resource sets; determine a first SRS resource set of the two or more SRS resource sets collides with a second SRS resource set of the two or more SRS resource sets; determining not to transmit SRS using the first SRS resource set; and transmitting SRS using the second SRS resource set.