MIMO Beamforming Feedback With Reduced Channel Matrix Dimension
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Solution Overview
Problem
In wireless communication systems, when the number of antennas at the transmitter (beamformer) is less than that at the receiver (beamformee), existing closed-loop MIMO communication methods face challenges in performing effective beamforming without increasing processing capabilities or circuit size, leading to reduced communication efficiency and increased overhead.
Innovation Solution
The system notifies the receiver of a maximum dimension for computing the transmission weight matrix, allowing it to suppress the channel matrix dimension to match the transmitter's processing capability, enabling efficient beamforming by transmitting a training sequence corresponding to the transmitter's antennas and estimating the channel matrix, thereby reducing circuit size and overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiver computes the transmission weight matrix using the full channel matrix dimension, then beamforming accuracy is improved, but circuit size and processing capability requirements increase
Solution Approach 1:
The patent extracts only the necessary portion of the channel matrix (N×N dimension corresponding to the transmitter's antenna count) from the full channel matrix (M×N dimension) for beamforming computation. This extraction principle reduces the matrix dimension used in calculating the transmission weight matrix, thereby decreasing circuit size and processing requirements while maintaining beamforming accuracy for the actual transmission scenario.
2Reliability
If the receiver feeds back full channel information, then beamforming performance is improved, but communication overhead increases
Solution Approach 1:
The patent applies extraction by having the receiver feed back only the necessary channel information corresponding to the transmitter's antenna configuration (N dimensions) rather than the full channel matrix (M dimensions). This selective feedback reduces communication overhead while providing sufficient information for the transmitter to compute accurate beamforming weights for its actual transmission capabilities.
3Device complexity
If the transmitter has fewer antennas than the receiver, then device complexity is reduced, but beamforming effectiveness deteriorates
Solution Approach 1:
The patent changes the parameter of channel matrix dimension from the receiver's perspective (M×N) to the transmitter's processing perspective (N×N). By adjusting this dimensional parameter to match the transmitter's antenna count, the system enables effective beamforming computation with fewer transmitter antennas, maintaining beamforming effectiveness while respecting the transmitter's hardware constraints.
Data Source
AI summary
A wireless communication system is disclosed. The wireless communication system performs data transmission using spatially multiplexed streams from a first terminal including N antennas to a second terminal including M antennas (N and M are integers larger than or equal to 2 and N>H).