Virtual Antenna Transformation for Distributed CoBF Beamforming
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing CoBF techniques require centralized processing and full CSI aggregation, leading to high signaling overhead, increased latency, and scalability challenges, especially when the number of transmit antennas is less than receive antennas, and fail to support zero-interference beamforming in distributed systems.
Innovation Solution
Transform physical channel configurations with fewer transmit antennas into virtual channel configurations using precoding matrices based on independent SVD feedback at each station, enabling unequal modulation and coding schemes to achieve zero multi-user interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized processing and full CSI aggregation are used to compute joint precoding matrices, then zero multi-user interference beamforming is achieved, but signaling overhead increases and scalability deteriorates
Solution Approach 1:
The patent segments the centralized CoBF processing into distributed operations at each AP. Instead of one central unit aggregating full CSI from all STAs, each AP independently performs SVD on its local channel matrix and generates precoding matrices locally. This segmentation eliminates the need for full CSI aggregation and reduces signaling overhead while maintaining zero MUI performance.
Solution Approach 2:
The patent extracts only the essential information needed for precoding (singular values and vectors from local SVD) rather than transmitting complete CSI. Each STA feeds back compressed channel state information sufficient for the AP to compute precoding matrices, removing unnecessary data transmission while preserving the zero MUI beamforming capability.
2Reliability
If the number of transmit antennas is increased to match or exceed receive antennas, then zero-interference beamforming is supported, but hardware requirements and system overhead increase
Solution Approach 1:
The patent changes the mathematical approach from requiring Nt ≥ Nr antenna configuration to working with any antenna configuration. By using SVD-based precoding with virtual channel transformation, the system achieves zero MUI beamforming without needing to increase the number of physical transmit antennas, thus avoiding additional hardware requirements.
3Reliability
If joint SVD processing is performed across all APs, then coordinated beamforming is achieved, but implementation difficulty increases in distributed systems
Solution Approach 1:
The patent divides the joint SVD processing into independent local SVD operations at each AP. Instead of requiring centralized coordination for joint decomposition, each AP separately performs SVD on its channel matrix and computes its own precoding matrices. This segmentation makes distributed implementation straightforward while maintaining coordinated beamforming functionality.
4Measurement precision
If full CSI aggregation is implemented, then accurate precoding matrices are computed, but feedback overhead increases
Solution Approach 1:
The patent extracts only the critical components of CSI (singular values and dominant right singular vectors) needed for precoding matrix computation. Each STA performs SVD locally and feeds back compressed representations sufficient for the AP to reconstruct precoding matrices, significantly reducing feedback overhead while maintaining the precision required for accurate beamforming.
Data Source
AI summary
A method of configuring a coordinate beamforming (CoBF) transmission in a wireless communication system is provided. The method includes: identifying a channel configuration between a plurality of access points (APs) and a plurality of stations (STAs), wherein a total number of physical transmit antennas per AP is less than a total number of physical receive antennas across the STAs; applying a pre-processing operation, to each STA, to convert the channel configuration into a virtual channel configuration in which a number of physical transmit antennas per AP is greater than or equal to the total number of virtual receive antennas across the STAs; generating one or more precoding matrices based on the virtual channel configuration; precoding, by the APs, data streams using the one or more precoding matrices; and transmitting, from the APs to the STAs, the precoded data streams.