Uplink CSI Acquisition Using Sparse SRS for Delay Path Capture
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Solution Overview
Problem
Existing SRS resource configurations in 5G NR systems fail to accurately capture transmission paths with smaller delays due to limited bandwidth and power constraints, leading to incomplete channel delay information.
Innovation Solution
The network side device configures SRS resources based on preset bandwidth, frequency domain density, and time domain parameters to enhance the precision of uplink channel state information acquisition, allowing terminals to send SRS in frequency hopping modes and adjust frequency domain density to improve signal coverage and capture diverse delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the terminal sends SRS on a larger bandwidth to capture transmission paths with smaller delays, then the channel delay information accuracy is improved, but the terminal power consumption increases and uplink coverage decreases
Solution Approach 1:
The patent divides the uplink channel measurement into two stages: first, the network side device performs initial channel measurement using downlink reference signals; second, the terminal performs refined measurement only on selected sub-bands where transmission paths with smaller delays are likely to exist. This segmentation allows accurate delay information capture without requiring the terminal to transmit SRS across the entire bandwidth, thus reducing power consumption.
Solution Approach 2:
The network side device performs preliminary channel measurement and identification of dominant transmission paths using downlink reference signals before requesting uplink SRS transmission. Based on this preliminary information, the network can configure targeted SRS resources on specific sub-bands, allowing the terminal to focus its transmission power on critical frequency regions rather than spreading power across all subcarriers.
2Quantity of substance
If the network side device configures SRS resources with small frequency interval (Comb parameter=2), then the frequency domain density is high, but the transmission paths with smaller delays cannot be captured
Solution Approach 1:
The patent dynamically adjusts the Comb parameter based on channel conditions and measurement requirements. When transmission paths with smaller delays need to be captured, the system increases the frequency interval (e.g., Comb parameter=4 or higher) to provide sufficient frequency spacing for resolving small delays. When high frequency domain density is sufficient, the system can use smaller Comb parameters to reduce terminal power consumption.
3Loss of information
If the terminal sends SRS on more subcarriers to improve delay capture, then the channel state information accuracy is improved, but the uplink coverage for edge terminals decreases
Solution Approach 1:
The patent applies local quality by concentrating SRS transmission resources on specific sub-bands where channel measurement is most critical for capturing transmission paths with smaller delays. Instead of uniform SRS transmission across all subcarriers, the system configures denser SRS resources locally in frequency regions identified as important based on downlink channel measurements, while reducing or eliminating SRS transmission in other regions. This localized approach maintains channel state information completeness while reducing overall power consumption and improving uplink coverage.
Data Source
AI summary
The present disclosure relates to the technical field of communications, and in particular to a method and apparatus for acquiring uplink channel state information, which are used for acquiring a transmission path with a relatively low delay. The method comprises: a network side device generating SRS resource configuration information on the basis of a preset bandwidth parameter, a frequency domain density parameter and a time domain parameter, and receiving at least one SRS returned by a terminal on the basis of the SRS resource configuration information; and then the network side device measuring, on the basis of the at least one SRS, an uplink channel used by the terminal, and determining corresponding uplink channel state information. In this way, SRS resource configuration information is generated by means of a preset bandwidth parameter and frequency domain density parameter, such that a bandwidth configuration of an SRS resource can be increased, and a frequency domain density of the SRS resource can be reduced, thereby improving a signal to interference plus noise ratio of each SRSRE; and a network side device can capture transmission paths with different time delays, thereby designing a port selection codebook with a higher precision.