UL-RS Port Mapping With Cyclic Shift Separation for Multi-TRP
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Solution Overview
Problem
In multi-TRP operation, the use of a same SRS sequence by UEs served by different TRPs leads to cross-SRS interference due to varying propagation delays, reducing SRS capacity and channel-estimation quality in coherent joint transmission scenarios.
Innovation Solution
Adapting the cyclic shift separation between UL-RS ports belonging to the same UE and/or different UEs by configuring specific cyclic shift and comb allocations in UL-RS configurations, enabling robustness against delay shifts in multi-TRP environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same SRS sequence is used by UEs served by different TRPs, then SRS capacity is reduced, but cross-SRS interference increases due to varying propagation delays
Solution Approach 1:
The patent applies parameter changes by modifying the cyclic shift values assigned to different SRS ports. Specifically, it introduces a cyclic shift separation parameter that differentiates the cyclic shifts for ports belonging to different TRPs, thereby eliminating cross-SRS interference while maintaining the ability to serve multiple TRPs simultaneously.
Solution Approach 2:
The patent segments the SRS ports into different groups based on their association with different TRPs. By assigning different cyclic shift values to ports from different TRPs, it creates distinct signal signatures that prevent interference between TRPs while allowing the system to maintain high SRS capacity.
2Reliability
If cyclic shift separation is increased between UL-RS ports, then robustness against delay shifts is improved, but the number of multiplexable UEs per comb is reduced
Solution Approach 1:
The patent applies local quality by assigning different cyclic shift separation values to different port configurations based on their specific requirements. Ports associated with the same TRP can use smaller cyclic shift separations, while ports from different TRPs use larger separations, optimizing the balance between robustness and capacity locally for each port configuration.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the cyclic shift configuration to be adjusted based on the specific TRP association and propagation delay characteristics. This enables the system to dynamically optimize cyclic shift values for different operational scenarios, maximizing both robustness and capacity under varying conditions.
Data Source
AI summary
Various embodiments described herein provide for a method and system to adapt uplink reference signals (UL-RS) resource configurations to handle Multiple Transmission Reception Point (Multi-TRP) operation for 5G advanced and/or 6G by adapting the cyclic shift separation between UL-RS ports belonging to the same User Equipment (UE) and/or adapting the cyclic shift separation between UL-RS ports belonging to different UEs. In an embodiment, a UE can receive a message from a network node containing a reference signal configuration that has a cyclic shift and comb allocation for a UL reference signal resource. The UE can then transmit the UL-RS based on the UL-RS configuration. Likewise, a network node can send a message to the UE containing a reference signal configuration that has a cyclic shift and comb allocation for a UL reference signal resource. The network node can then receive the UL-RS that was transmitted based on the UL-RS configuration.