Multi-TRP PUSCH Repetition Mapping for Reliable Uplink Beamforming
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Solution Overview
Problem
Existing wireless communication systems, particularly in 5G NR, face challenges in enhancing the reliability and efficiency of uplink transmissions in multi-Transmission Reception Point (TRP) scenarios, especially in high-frequency bands like FR2, due to varying channel conditions and the need for clear beamforming and panel selection.
Innovation Solution
The proposed solution involves a User Equipment (UE) that supports multi-TRP operations by receiving specific transmit precoder matrix indications (TPMI) and SRS resource sets from a Base Station (BS), enabling cyclical mapping patterns for Physical Uplink Shared Channel (PUSCH) repetitions to different TRPs, and utilizing fast panel switching for beamforming with extended SRS resource sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-TRP operations are implemented to improve transmission reliability, then transmission reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the uplink transmission by dividing PUSCH repetitions across multiple TRPs, with each TRP receiving specific repetitions according to a cyclical mapping pattern. The UE maintains separate SRS resource sets for different TRPs and applies different TPMIs for different TRPs, enabling independent optimization of each transmission path while maintaining overall system reliability
Solution Approach 2:
The patent implements dynamic panel switching at the UE side, where the UE rapidly switches between different antenna panels to communicate with different TRPs. This dynamic adaptation allows the system to respond to varying channel conditions in real-time, improving reliability without requiring static complex configurations
2Productivity
If cyclical mapping pattern is used for PUSCH repetitions across multiple TRPs, then transmission efficiency is improved, but processing complexity increases
Solution Approach 1:
The patent employs a cyclical mapping pattern where PUSCH repetitions are transmitted to TRPs in a periodic sequence (e.g., TRP1, TRP2, TRP1, TRP2...). This periodic structure simplifies the mapping logic compared to arbitrary patterns, as the UE can use modular arithmetic to determine which TRP receives which repetition, reducing processing complexity while maintaining high transmission efficiency
Solution Approach 2:
The patent changes the mapping parameter from a static one-to-one correspondence to a dynamic cyclical mapping based on repetition index. This parameter transformation allows the system to efficiently utilize multiple TRPs by varying the target TRP selection based on the repetition number, improving throughput without requiring complex real-time decision algorithms
3Measurement precision
If extended SRS resource sets are configured for codebook-based transmissions, then beamforming precision is improved, but signaling overhead increases
Solution Approach 1:
The patent performs preliminary configuration of extended SRS resource sets through RRC signaling before actual PUSCH transmissions. By pre-configuring multiple SRS resources with different spatial filters and associating them with different TRPs, the system eliminates the need for dynamic signaling during transmission, reducing overhead while maintaining precise beamforming capabilities
Solution Approach 2:
The patent uses SRS (Sounding Reference Signal) as a copy/probe of the uplink channel characteristics. By transmitting SRS signals through different antenna panels and measuring the responses at multiple TRPs, the system obtains precise channel state information without requiring direct data transmission for channel estimation, thus maintaining beamforming precision while separating estimation overhead from data transmission
Data Source
AI summary
A method performed by a UE for communicating with a plurality of TRPs is provided. The method includes: receiving, from the BS, one or more RRC messages that configure the UE with a first SRS resource set associated with a first TRP, a second SRS resource set associated with a second TRP, and a cyclical mapping pattern for a plurality of PUSCH repetitions, a usage of the first SRS resource set and the second SRS resource set being configured for codebook-based transmissions; and transmitting the plurality of PUSCH repetitions based on the cyclical mapping pattern at least by: transmitting a first PUSCH repetition of the plurality of PUSCH repetitions to the first TRP according to the first SRS resource set; and transmitting a second PUSCH repletion of the plurality of PUSCH repetitions to the second TRP according to the second SRS resource set after transmitting the first PUSCH repetition.