SRS Delay-Beam Compression for Lower Fronthaul Reporting Load
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Solution Overview
Problem
In wireless communications systems, the payload of sounding reference signal (SRS) reports is large due to the number of antennas and bandwidth, leading to increased latency and inefficiencies in fronthaul traffic.
Innovation Solution
The radio unit (RU) compresses SRS signals from the frequency-antenna domain into a delay-beam domain, reducing the payload of the SRS report, which is then transmitted to the distributed unit (DU) for precoder configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If SRS signals are transmitted in frequency-antenna domain without compression, then complete signal information is preserved, but payload size increases leading to increased latency and fronthaul traffic bursts
Solution Approach 1:
The patent transforms the SRS signal from frequency-antenna domain to delay-beam domain through mathematical transformation (e.g., DFT/IDFT operations). This parameter change in representation domain enables sparse representation where most coefficients are near-zero, allowing compression while preserving essential signal characteristics for accurate channel estimation and precoder configuration
Solution Approach 2:
The patent extracts and transmits only the significant non-zero coefficients from the delay-beam domain representation, discarding or compressing the numerous near-zero coefficients. This selective extraction reduces payload size dramatically while maintaining sufficient information for the DU to reconstruct the channel state and configure precoders accurately
2Measurement precision
If SRS signals are transmitted without compression, then full signal detail is available, but fronthaul traffic bursts increase and system efficiency decreases
Solution Approach 1:
By changing the representation parameters from frequency-antenna domain to delay-beam domain, the patent reveals the inherent sparsity structure of wireless channels. The delay-beam domain transformation concentrates channel energy into fewer significant coefficients, enabling efficient compression that maintains measurement precision while improving transmission efficiency through reduced payload sizes
Solution Approach 2:
The patent transmits a partial representation of the SRS signal by sending only the significant delay-beam coefficients rather than the complete frequency-antenna domain data. This partial transmission is sufficient for accurate channel estimation and precoder configuration, achieving high productivity with reduced fronthaul traffic while maintaining measurement precision
3Quantity of substance
If SRS compression is performed at RU, then payload size is reduced, but processing complexity at RU increases
Solution Approach 1:
The patent implements domain transformation (frequency-antenna to delay-beam) at the RU using efficient mathematical algorithms such as DFT and IDFT operations. While this adds processing steps, the transformations leverage structured mathematical properties that can be computed efficiently, and the RU gains capability to perform beyond low-PHY layer functions, enabling intelligent compression decisions based on channel sparsity characteristics
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. The described techniques relate to improved methods, systems, devices, and apparatuses that support sounding reference signal (SRS) compression techniques for SRS reporting. For example, the described techniques may enable a radio unit (RU) to compress a received SRS signal to reduce a payload of an SRS report. For example, the RU may compress the received SRS signal from a frequency-antenna domain into a delay-beam domain. The RU may accordingly transmit the SRS report to a distributed unit (DU) with a relatively smaller payload than a non-compressed SRS report. The DU may recover the non-compressed received SRS signal from the compressed SRS signal and configure the RU with a precoder based on the received SRS signal. In some examples, the DU may configure the RU to perform SRS compression based on a capability of the RU to perform sparse SRS compression.