Successive Beamforming Adaptive Codebook for Time-Varying Channels
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Solution Overview
Problem
Conventional beamforming techniques for wireless communication systems are inadequate in handling time-varying fading channels, as they do not effectively exploit inter-frame correlations in channel fading, leading to suboptimal performance and increased feedback requirements.
Innovation Solution
The proposed solution involves a successive beamforming algorithm that utilizes vector quantization technology, including predictive and finite state vector quantization, to construct a time-varying adaptive codebook, which leverages knowledge from previous fading blocks for improved transmit beamforming, reducing the need for multiple codebooks and enhancing performance across various fading speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional beamforming techniques are used, then the system can operate with simple fixed weightings, but the performance is suboptimal in time-varying fading channels and feedback requirements increase
Solution Approach 1:
The patent applies preliminary action by using knowledge from previous fading blocks to construct the adaptive codebook for the current block. The successive beamforming algorithm pre-processes channel information from past blocks to create a codebook that anticipates current channel conditions, reducing the need for extensive feedback while maintaining optimal performance in time-varying fading channels
2Adaptability or versatility
If multiple codebooks are used to handle different fading speeds, then performance across various fading speeds improves, but implementation complexity increases
Solution Approach 1:
The patent implements universality by designing a single adaptive codebook construction method that works across different fading speeds. The successive beamforming algorithm with vector quantization creates a universal solution that adapts to various channel conditions without requiring separate codebooks for different fading scenarios, thereby maintaining versatility while reducing implementation complexity
Solution Approach 2:
The patent applies dynamics by creating a time-varying adaptive codebook that evolves with channel conditions. The codebook is dynamically constructed using successive beamforming that incorporates information from previous fading blocks, allowing the system to adapt to changing fading speeds without requiring multiple static codebooks
3Device complexity
If inter-frame correlations in channel fading are not exploited, then the beamforming algorithm is simpler, but performance in time-varying fading channels deteriorates
Solution Approach 1:
The patent applies feedback by utilizing channel information from previous fading blocks as feedback for constructing the current codebook. The successive beamforming algorithm incorporates inter-frame correlations by feeding back channel statistics and using them to adapt the codebook construction, thereby improving performance in time-varying fading channels while maintaining reasonable algorithm complexity
Data Source
AI summary
An improvement in a method of transmit beamforming between a transmitter (16) and a receiver (18) for a time varying lading channel comprises the step of performing transmit beamforming using less than complete knowledge of the previous fading blocks to design a codebook (26a) of a current fading block with each time frame. One embodiment comprises a successive beamforming algorithm and a second embodiment comprises a vector quantization beamforming algorithm. A fading parameter α is determined at least in the transmitter or receiver by monitoring a mobile Doppler frequency.