Low Bit-Rate Feedback Mapping for Wireless MIMO Systems
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Solution Overview
Problem
Current low bit-rate feedback schemes in wireless communication systems are computationally intensive and require significant hardware resources, making them inefficient for MIMO and MISO beamforming applications.
Innovation Solution
A method is introduced that maps information to regions with zero values, allowing for reduced computational complexity by using circuitry to provide imaginary and real portions of channel matrix entries without multipliers, thereby generating a mapped codebook for quantization and beamforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a low bit-rate feedback scheme is implemented to reduce feedback channel bandwidth requirements, then feedback efficiency is improved, but computational complexity and hardware resource requirements increase significantly
Solution Approach 1:
The patent changes the parameter representation by mapping complex channel coefficients to a reduced set of discrete regions (5 regions per complex plane quadrant). Instead of using continuous or high-precision quantization, the system divides the complex plane into regions and assigns indices, reducing feedback bits while maintaining acceptable accuracy. This parameter discretization resolves the contradiction by enabling low bit-rate feedback without requiring proportionally high computational complexity for processing.
Solution Approach 2:
The patent segments the complex channel coefficient space into multiple discrete regions (5 regions per quadrant, totaling 20 regions). Each region represents a quantized value that can be encoded with fewer bits. By segmenting the continuous channel state space into manageable discrete regions, the system achieves efficient low bit-rate feedback while the segmentation structure itself provides a framework for simplified computational processing at both transmitter and receiver.
2Measurement precision
If conventional quantization methods are used to represent spatial channel information, then measurement precision is maintained, but hardware resource requirements increase due to the need for multiple multipliers
Solution Approach 1:
The patent replaces expensive multiplier hardware with cheaper computational alternatives. Instead of using dedicated multiplier circuits for each channel coefficient quantization operation, the system uses lookup tables and additive operations based on the regional mapping approach. The complex multiplication H*ci is decomposed into operations that can be performed using adders and pre-computed values, effectively substituting expensive hardware with simpler, more resource-efficient components while maintaining measurement precision.
Solution Approach 2:
The patent substitutes the mechanical multiplication operation with an equivalent computational approach using regional indexing and additive operations. The complex multiplication between channel matrix H and codebook vector ci is replaced by determining which region the product falls into and using pre-computed regional representatives. This substitution eliminates the need for physical multiplier hardware while preserving the essential function of computing channel quality metrics for feedback.
Data Source
AI summary
Low bit-rate feedback wireless communication systems with reduced computational complexity is described. A first set of information is obtained and mapped to a set of regions. Each region of the set of regions has at least one portion with a zero value. The at least one portion is selected from a group consisting of an imaginary portion and a real portion. A second set of information is provided responsive to the mapping and stored for access by at least one component of the wireless communication system.