MIMO CSI Feedback Codebook for Near-Field Subarray Precoding
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Solution Overview
Problem
Existing MIMO wireless communication systems face challenges in near-field scenarios due to significant gain loss when receiving terminals are located in the near-field region, as traditional far-field assumptions no longer hold, and existing near-field precoding schemes have high computational complexity and incompatibility with standard protocols.
Innovation Solution
A method is proposed to divide a large MIMO array into subarrays, using a subarray precoding scheme with a codebook based on a basis vector model to facilitate channel state information feedback, maintaining compatibility with existing protocols and reducing computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional far-field precoding is used in near-field scenarios, then protocol compatibility is maintained, but beamforming gain is significantly lost
Solution Approach 1:
The patent divides the large MIMO array into multiple subarrays, where each subarray operates independently with its own precoding. This segmentation allows the system to maintain far-field protocol compatibility for each subarray while collectively addressing near-field communication needs, resolving the contradiction between protocol compatibility and beamforming gain.
Solution Approach 2:
The patent applies different precoding strategies to different subarrays based on their specific spatial characteristics and channel conditions. Each subarray receives customized precoding tailored to its local environment, enabling optimized beamforming gain while maintaining overall system compatibility with existing protocols.
2Reliability
If existing near-field precoding schemes are implemented, then near-field communication performance is improved, but computational complexity increases significantly
Solution Approach 1:
By segmenting the large MIMO array into multiple subarrays, the patent reduces the computational burden on each individual subarray. The precoding calculations are distributed across smaller units rather than being performed on the entire large array, significantly reducing overall computational complexity while maintaining near-field communication performance.
Solution Approach 2:
The patent employs partial precoding by applying precoding only to the necessary subarrays based on channel state information and communication needs. This partial action approach avoids the excessive computational complexity of fully precoding the entire array, achieving adequate near-field performance with reduced computational resources.
3Productivity
If a large MIMO array is used to increase spectrum resources, then communication capacity is improved, but the near-field region expands making far-field assumptions invalid
Solution Approach 1:
The patent segments the large MIMO array into multiple subarrays, which allows the system to maintain far-field protocol compatibility for each subarray while collectively providing the capacity of a large array. This segmentation approach enables the system to operate in near-field scenarios without sacrificing the benefits of large-scale MIMO.
Solution Approach 2:
The patent creates a universal precoding framework that can handle both far-field and near-field scenarios through the subarray structure. The same subarray-based approach works for different communication scenarios, making the system adaptable to various field conditions while maintaining communication capacity.
Data Source
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AI summary
A channel information feedback method, an electronic device, and a storage medium, where the channel information feedback method includes: determining a measurement result of channel state information according to a measured reference signal (S110); determining a codebook, where the codebook includes a sub-codebook for r transmission layers, where r = 1, 2, ..., R, and R is a positive integer (S120); determining a codeword W from the codebook (S130); and feeding back indication information of the codeword W (S140), where the codeword W is a matrix of N rows and r columns formed by r column vectors V1, V2, ..., Vr having a length of N, N > 1, and r ≥ 1; and the r column vectors of the codeword W are constructed according to the following basis vector model: u=α1ν1α2ν2α3ν3⋮αKνK; where the basis vector model u includes K sub-vectors, the length of a k-th sub-vector vk is Nk, αk is a sub-vector coefficient, K ≥ 1, 1 ≤ k ≤ K, Nk ≥ 1, and the value of K is determined based on the value of r.