SRS Comb Offset and Cyclic Shift Hopping for TDD CJT Interference
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Solution Overview
Problem
In Time-Division-Duplexing Coherent Joint Transmission (TDD CJT) systems, interference among Sounding Reference Signals (SRS) transmitted from different User Equipment (UEs) served by different Transmission and Receiving Points (TRPs) is not effectively randomized, leading to performance degradation.
Innovation Solution
Implement comb offset hopping and cyclic shift hopping for SRS, limited within specific subsets, to randomize interference and improve orthogonality among SRS ports, supporting the coexistence of legacy and new UEs within a cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If comb offset hopping and cyclic shift hopping are implemented for SRS, then interference randomization among SRS transmissions is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically varying comb offsets and cyclic shifts across different transmission occasions. Specifically, the comb offset is changed according to a hopping pattern defined by parameters such as combOffsetHoppingOffset and combOffsetHoppingPattern, while the cyclic shift is varied using parameters like cyclicShiftHoppingOffset. These parameter changes enable interference randomization among SRS transmissions from different UEs without requiring complex system architecture modifications.
2Reliability
If comb offset hopping and cyclic shift hopping are implemented for SRS, then orthogonality among SRS ports is improved, but device complexity increases
Solution Approach 1:
The patent maintains orthogonality among SRS ports by carefully managing parameter changes within defined ranges. The comb offset hopping is constrained by parameters such as transmissionComb and combOffsetHoppingOffset, ensuring that orthogonal resources are preserved. Similarly, cyclic shift hopping is controlled within the range defined by maxCyclicShift and cyclicShiftHoppingOffset. This approach ensures orthogonality is maintained while avoiding the need for complex resource allocation mechanisms.
3Reliability
If comb offset hopping and cyclic shift hopping are implemented for SRS, then TDD CJT performance is improved, but device complexity increases
Solution Approach 1:
The patent enhances TDD CJT performance through parameter changes in comb offset and cyclic shift hopping, which randomize interference among SRS transmissions from different UEs served by different TRPs. The comb offset hopping uses parameters like combOffsetHoppingOffset and combOffsetHoppingPattern, while cyclic shift hopping uses cyclicShiftHoppingOffset. These parameter variations improve the statistical properties of interference without requiring complex coordination between TRPs or UEs.
Solution Approach 2:
The patent introduces dynamics by making comb offsets and cyclic shifts time-varying rather than static. The comb offset changes according to a hopping pattern that can be configured with different periods and offsets, while the cyclic shift varies across transmission occasions. This dynamic behavior enables the system to adapt to changing interference conditions and improve TDD CJT performance without requiring complex real-time coordination.
Data Source
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AI summary
The arrangements described herein relate to systems, methods, apparatuses, and non-transitory computer-readable media for a wireless communication device receiving from a network device, at least one of a first parameter indicating a subset of comb offsets or a second parameter indicating a subset of cyclic shifts. The wireless communication device determines based on a transmission time instant and the at least one of the first parameter or the second parameter, at least one of a comb offset or a cyclic shift for each Sounding Reference Signal (SRS) port associated with an SRS resource. The wireless communication device transmits to the network device, an SRS according to the at least one of the comb offset or the cyclic shift.