MIMO Symbol Detection Circuit Using QR Decomposition
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Solution Overview
Problem
In MIMO communication systems, the evaluation of all possible combinations of symbols transmitted from multiple antennas becomes infeasible for higher order modulations and a large number of antennas, making maximum-likelihood detection impractical due to increased complexity and noise interference.
Innovation Solution
A circuit and system that utilize QR decomposition to reduce the complexity of symbol detection by decomposing the channel matrix into a triangular form, allowing for the calculation of partial distances for each transmitting antenna, and binning of these distances based on signal-to-noise ratio to select the most likely symbol combinations, thereby reducing the number of combinations to be evaluated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If maximum-likelihood detection evaluates all possible symbol combinations, then detection accuracy is improved, but computational complexity becomes infeasible for higher order modulations and large number of antennas
Solution Approach 1:
The patent segments the exhaustive search space by organizing symbols into groups based on their partial distances to the received signal. Instead of evaluating all possible combinations, the detector divides the constellation into multiple groups and only evaluates combinations within these groups, significantly reducing computational complexity while maintaining detection accuracy.
Solution Approach 2:
The patent applies partial action by evaluating only a subset of symbol combinations rather than all possible combinations. By using partial distance calculations and grouping symbols based on their proximity to the received signal, the detector performs sufficient evaluation to achieve accurate detection without the excessive computational burden of exhaustive search.
2Productivity
If the number of transmitting antennas is increased to improve data transfer rate, then productivity increases, but the number of possible symbol combinations increases exponentially
Solution Approach 1:
The patent segments the exponentially growing search space by organizing symbols from multiple antennas into structured groups based on partial distances. This segmentation allows the detector to handle MIMO systems with multiple transmitting antennas efficiently by reducing the combinatorial explosion of possible symbol combinations through systematic grouping and selective evaluation.
3Productivity
If higher order modulation is used to increase data transfer rate, then productivity increases, but the number of symbols in constellation increases making evaluation infeasible
Solution Approach 1:
The patent applies partial action by evaluating only the most promising symbol combinations rather than all symbols in the high-order constellation. By calculating partial distances and grouping symbols based on their proximity to the received signal, the detector performs sufficient evaluation to achieve accurate detection without the excessive computational burden of examining every symbol in high-order modulations like 64-QAM or 256-QAM.
Data Source
AI summary
Circuits are provided for detecting symbols transmitted from multiple transmitting antennas to multiple receiving antennas. A circuit includes distance blocks, selectors, and an identifier block. Each distance-block includes at least one sub-block, and each sub-block inputs a candidate for a corresponding transmitting antenna. The sub-block determines partial distances for pairings of the candidate and each symbol in a constellation from a partial distance of the candidate and signals received at the receiving antennas. At least one selector assigns each pairing for each candidate for a corresponding transmitting antenna to a bin having a range that includes the partial distance of the pairing. The selector selects candidates for a successive transmitting antenna from the bins having the smaller ranges. The identifier block selects a final candidate that is one of the pairings for a last transmitting antenna having a smaller partial distance.