SRS Beam Subset Selection for TDD mmWave Overhead Reduction
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Solution Overview
Problem
Traditional mmWave SRS configuration schemes in cellular TDD systems face significant overhead and latency due to the evaluation of all combinations of beam directions between user equipment (UE) and base station, which hinders efficient SRS transmission and reception.
Innovation Solution
The proposed method involves selecting a subset of beam directions for SRS transmission and reception based on feedback messages, reducing the number of combinations evaluated and thus minimizing overhead and latency, allowing for more frequent SRS reporting and supporting higher UE mobility and multiplexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all combinations of beam directions are evaluated for SRS transmission, then measurement precision is improved, but device complexity and loss of time increase
Solution Approach 1:
The patent segments the complete set of beam directions into multiple subsets, where each subset contains a limited number of beam directions. The UE evaluates SRS only within its assigned subset rather than all possible beam combinations. This segmentation reduces the complexity of SRS configuration while maintaining adequate measurement precision through the use of multiple subsets that collectively cover the full beam space.
Solution Approach 2:
The patent applies partial action by having the UE evaluate only a subset of all possible beam directions for SRS transmission. Instead of exhaustively evaluating all beam combinations, the system uses feedback messages to identify and evaluate only the most relevant beam directions, achieving sufficient measurement precision with reduced complexity and time overhead.
2Measurement precision
If all combinations of beam directions are evaluated for SRS transmission, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent divides the beam direction evaluation into multiple subsets assigned to different UEs or time periods. By segmenting the evaluation space, the system reduces the time each UE spends on SRS configuration while maintaining overall measurement precision through the collective coverage of multiple subsets.
Solution Approach 2:
The system performs partial evaluation of beam directions by using feedback messages to identify only the most promising beam directions for SRS transmission. This avoids the time-consuming exhaustive evaluation of all beam combinations while maintaining adequate measurement precision for beam management.
3Productivity
If subset of beam directions is selected for SRS transmission, then productivity is improved, but measurement precision may be reduced
Solution Approach 1:
The patent segments the beam direction evaluation into multiple subsets, allowing more frequent SRS reporting within each subset. The use of multiple subsets ensures that collectively they cover the full beam space, maintaining measurement precision while enabling higher productivity through increased reporting frequency.
Solution Approach 2:
The system uses feedback messages from the network to identify which beam directions should be included in the subset for SRS transmission. This feedback mechanism ensures that the selected subset contains the most relevant beam directions, maintaining measurement precision while enabling more frequent and efficient SRS reporting.
Data Source
AI summary
A system and method of communicating sounding reference signals (SRSs) in a cellular time division duplex (TDD) mmWave system. A transmission point (TP) may transmit beamformed reference signals to a user equipment (UE), each of the beamformed reference signals having been transmitted according to a beam direction in a set of beam directions available to the TP. The TP may receive a feedback message from the UE that identifies one of the beamformed reference signals transmitted to the UE. The TP may select, from the set of beam directions available to the TP, a subset of beam directions for SRS reception based on the feedback message received from the UE, and receive uplink SRS signals according to beam directions in the subset of beam directions. The set of beam directions available to the TP includes at least one beam direction that is excluded from the subset of beam directions.