Hybrid Beamforming Pruning for Reduced Training Overhead
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Solution Overview
Problem
Current wireless communication systems, such as IEEE 802.11ad and 802.11ay, face inefficiencies in beam training due to the need to scan numerous beam combinations, leading to prolonged setup times and increased computational complexity, especially with limited RF chains and the requirement for hybrid precoding to multiplex multiple data streams.
Innovation Solution
A method for determining a select set of beam indices using hybrid precoding, which involves obtaining and processing subsets of beam index pairs through a pruning decision process, reducing the need for exhaustive searches by selecting a subset of candidates based on predefined metrics and prior information, thereby streamlining the beam selection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If exhaustive beam search is performed to find optimal beam pairs, then beam selection accuracy is improved, but beam training time and computational complexity increase significantly
Solution Approach 1:
The patent performs preliminary channel estimation and obtains channel state information before beam selection. This preliminary action provides prior information about the channel conditions, which is then used to guide the beam search process and reduce the number of beam combinations that need to be exhaustively searched, thereby reducing training time while maintaining accuracy
Solution Approach 2:
The patent changes the approach from exhaustive search of all beam combinations to a selective search based on channel state parameters. By using obtained channel metrics and prior information to identify promising beam pairs, the system transforms the beam selection from a brute-force parameter search to a targeted search based on channel characteristics
2Productivity
If hybrid precoding is implemented to multiplex multiple data streams, then data throughput is improved, but the number of beam combinations to scan increases
Solution Approach 1:
The patent segments the beam selection process into multiple stages: first obtaining channel state information, then using this information to prune the beam search space, and finally selecting beam pairs from the reduced set. This segmentation allows hybrid precoding to be implemented for multiple data streams while managing beam search complexity through progressive refinement
Solution Approach 2:
The patent extracts and utilizes channel state information and prior information from the system to identify and remove unpromising beam combinations from the search space. This extraction of useful information allows the system to focus computational resources on the most promising beam pairs, enabling hybrid precoding without proportionally increasing search complexity
3Device complexity
If limited RF chains are used to reduce hardware complexity, then device complexity is reduced, but the ability to apply fast-changing precoding weights to every antenna element is limited
Solution Approach 1:
The patent implements a dynamic beam selection approach where beam pairs are selected based on current channel state information and prior information. This dynamic adaptation allows the system to optimize beam selection for each transmission scenario, compensating for the limited RF chains by intelligently adapting to channel conditions rather than relying on static or exhaustive search methods
Solution Approach 2:
The patent utilizes feedback from channel estimation and prior information to guide beam selection. The system obtains channel state information, uses this feedback to prune the beam search space, and selects beam pairs that are optimal for the current channel conditions, thereby maintaining precoding flexibility despite limited RF chains
Data Source
AI summary
Systems and methods of beam selection for hybrid beamforming are disclosed. Determining a select set of beam indices for use with transmissions to a receiver using hybrid precoding includes obtaining metrics for a first set of pairs of beam indices for use with the transmissions, where each pair includes a transmit beam index for a transmit antenna and a receive beam index for a receiver antenna. The method also includes selecting a first subset of the first set of pairs according to a first pruning decision, where the first subset includes at least one of the pairs. The method also includes processing only the first subset to determine the selected set of beam indices for use with the transmissions using hybrid precoding. In this way, a beam selection is made without the need to perform an exhaustive search of beams which is typically a time consuming process.