SRS Resource Mapping for Cross-Subband Base Combination
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Solution Overview
Problem
Existing wireless communication systems, particularly in 5G NR, face challenges in deriving frequency domain-spatial domain bases for precoding of channel state information due to limitations in combining SRS measurements across subbands, especially in frequency-division duplexing and time-division duplexing scenarios.
Innovation Solution
Configuring user equipment (UE) with two SRS resource allocations for each SRS resource set, including one based on subband sounding with frequency hopping and another based on wideband sounding without frequency hopping, to facilitate the derivation of frequency domain-spatial domain bases by the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If SRS is sounded per band with frequency hopping, then SRS capacity and frequency coverage are improved, but the base station is unable to combine frequency domain bases and perform joint processing across subbands
Solution Approach 1:
The patent segments SRS resources into multiple resource allocations with different frequency comb configurations. Each allocation uses a different comb size (e.g., comb-2, comb-4, comb-8), dividing the frequency domain into distinct patterns. This segmentation allows the base station to receive SRS on different frequency subsets and combine them to form complete frequency domain bases, resolving the contradiction between maintaining high SRS capacity through frequency hopping and enabling frequency domain base combination for reliable channel estimation.
2Reliability
If multiple SRS resource allocations with different frequency comb configurations are configured, then frequency domain base combination capability is improved, but device complexity and configuration overhead increase
Solution Approach 1:
The patent implements a universal SRS resource allocation framework where a single SRS resource can be configured with multiple resource allocations sharing common parameters (time domain position, frequency domain position, sequence parameters) while varying only the frequency comb configuration. This multi-functionality approach allows the same SRS resource to serve multiple purposes across different frequency subsets, enabling frequency domain base combination without requiring separate SRS resources for each frequency subset, thereby reducing configuration overhead and device complexity.
Data Source
AI summary
A user equipment (UE) may receive, from a base station, a sounding reference signal (SRS) configuration indicating at least two resource allocations for each SRS resource of an SRS resource set, and each of the at least two resource allocations may include a time resource allocation and a frequency resource allocation. The UE may further transmit, to the base station, an SRS on a respective SRS resource of the SRS resource set based on one of the at least two resource allocations for the respective SRS resource. The base station may transmit, to the UE, the SRS configuration indicating at least two resource allocations for each SRS resource of an SRS resource set, and receive, from the UE, the SRS on a respective SRS resource of the SRS resource set based on the one of the at least two resource allocations for the respective SRS resource.