Iterative Zero Forcing Beamforming for MU-MIMO Interference Mitigation
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Solution Overview
Problem
Conventional MU-MIMO downlink beamforming techniques face performance degradation due to co-channel interference and high computational complexity, especially when dealing with multiple co-scheduled users and channel estimation errors, limiting their practical application.
Innovation Solution
An iterative zero forcing (IZF) scheme is proposed, which determines beamforming vectors by considering practical receivers and iteratively updates them to mitigate interferences effectively, using eigenvectors of covariance matrices and regularization parameters to reduce computational complexity and overcome dimension limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional MU-MIMO downlink beamforming techniques are used, then system capacity is improved through multiple transmitting and receiving antennas, but co-channel interference causes performance degradation
Solution Approach 1:
The patent converts the harmful co-channel interference into useful information by using it to update beamforming vectors iteratively. The interference signals received at co-scheduled devices are processed to extract channel state information, which is then used to refine beamforming weights and reduce interference, transforming the harmful interference into a beneficial feedback mechanism for system optimization
Solution Approach 2:
The patent implements a feedback mechanism where beamforming vectors are iteratively updated based on channel estimations and interference observations from co-scheduled devices. The system continuously adjusts beamforming weights using feedback from channel state information to optimize performance and mitigate interference effects
2Object-affected harmful factors
If conventional beamforming techniques are used to mitigate interference, then interference between co-scheduled devices is reduced, but computational complexity increases
Solution Approach 1:
The patent applies partial action by iteratively updating only the necessary beamforming vectors based on current channel conditions and interference levels, rather than recalculating all parameters from scratch. This incremental approach reduces computational burden while maintaining effective interference mitigation
Solution Approach 2:
The patent changes parameters iteratively by updating beamforming vectors based on channel estimations and interference observations. The system adjusts beamforming weights dynamically through parameter optimization, using eigenvectors of covariance matrices and regularization parameters to reduce computational complexity while maintaining interference mitigation effectiveness
3Measurement precision
If beamforming vectors are updated using channel estimations, then beamforming performance is improved, but dimension limitations restrict application range
Solution Approach 1:
The patent transitions from traditional spatial dimension beamforming to incorporating temporal dimension through iterative updates. By updating beamforming vectors across multiple iterations based on channel estimations, the system effectively adds a time dimension to the beamforming process, enabling adaptation to scenarios where the number of antennas or beams at terminal devices exceeds those at the base station
Data Source
AI summary
According to embodiments of the present disclosure, downlink beamforming in MU-MIMO systems is proposed. Embodiments of the present disclosure take practical receivers into consideration, to further mitigate the interferences sensed by terminal devices. The beamforming scheme according to embodiments of the present disclosure has many advantages. For example, embodiments of the present disclosure tackle interferences from terminal device view, to mitigate the interferences which really affect the received signals of terminal devices. Embodiments of the present disclosure do not assume that terminal devices utilize Eigen receivers but consider more practical receivers used by the terminal devices to mitigate the interferences. Embodiments of the present disclosure have high flexibility, different interference cancelling methods can be used to replace the ZF method.