MIMO Spatial Multiplexing Decoder Using Segmented Euclidean Distance Search
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Solution Overview
Problem
Designing practical receivers for spatially multiplexed signals in MIMO systems is challenging due to the high complexity of decoding, particularly with methods like exhaustive search and iterative detection, which are prone to error propagation and increased latency.
Innovation Solution
A method that reduces the complexity of decoding by selecting possible values of the first symbol, estimating the second symbol, calculating Euclidean distances, and selecting the minimal distance, without implementing exhaustive search or iterative processes, allowing for optimal reception of spatially multiplexed signals with linear complexity in the constellation size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If exhaustive search is used to decode spatially multiplexed signals, then decoding accuracy is improved, but computational complexity increases exponentially
Solution Approach 1:
The patent segments the decoding process into two independent stages: first decoding the first symbol from the received signal, then decoding the second symbol from the residual signal after removing the first symbol's contribution. This segmentation transforms the exponential complexity of exhaustive search into linear complexity by dividing the problem into manageable parts that can be solved sequentially.
Solution Approach 2:
The patent performs preliminary decoding of the first symbol before decoding the second symbol. By first estimating and removing the contribution of the first symbol from the received signal, the system simplifies the subsequent decoding of the second symbol, avoiding the need to simultaneously evaluate all possible symbol combinations.
2Reliability
If iterative detection is used to decode spatially multiplexed signals, then decoding performance is improved, but latency increases
Solution Approach 1:
The patent segments the detection process into sequential non-iterative stages, where the first symbol is decoded once and the second symbol is decoded once from the residual signal. This eliminates the need for multiple iterative passes, thereby reducing latency while maintaining decoding performance through the systematic separation of detection steps.
3Device complexity
If sequential decoding without residual signal removal is used, then device complexity is reduced, but error propagation occurs
Solution Approach 1:
The patent extracts and removes the contribution of the first decoded symbol from the received signal before decoding the second symbol. This extraction step prevents error propagation by ensuring that errors in the first symbol decoding do not contaminate the second symbol decoding process, as the first symbol's contribution is completely removed from the residual signal.
Data Source
AI summary
An embodiment of a method for decoding a received signal function of at least a channel matrix B, and of a first and second symbols S1, and S2 belonging to a signal constellation. The method comprises the steps of: selecting a set of values of the first symbol S1 in the signal constellation; for each selected value of the first symbol S1: estimating the value of the second symbol S2 to generate an estimated value of the second symbol; calculating an Euclidean distance between the received signal and a noiseless signal defined by the first symbol with said selected value and by the second symbol with said estimated value; selecting the minimal Euclidean distance among the Euclidean distances respectively calculated for the different selected values of the set of possible values of the first symbol; and selecting decoded first and second symbols corresponding to the selected minimum Euclidean distance.