Sphere Decoding for MIMO Signal Detection Complexity

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The complexity of signal detection in MIMO systems increases significantly with higher order MIMO systems, leading to increased system complexity, chip processor area, and power consumption, especially when the orthogonal characteristics of the MIMO channel decay, making it difficult to maintain high signal receiving performance.

Innovation Solution

The sphere decoding method uses the Schnorr & Euchner enumeration rule to select preferred points from constellation points based on the signal-to-noise ratio (SNR) of each detection layer, reducing detection complexity while maintaining signal receiving performance by calculating partial Euclidean distances only for a subset of constellation points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the value of K is increased to enhance signal receiving performance, then the receiving performance is improved, but the system complexity greatly increases

Engineering Contradiction:
Improvesignal receiving performanceVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the constellation points into multiple subsets based on their Euclidean distances from the received signal. Instead of uniformly processing all K preferred points, the method segments them into different groups (first subset, second subset, etc.) with different numbers of points. This segmentation allows the system to allocate different computational resources to different subsets, reducing the overall complexity while maintaining receiving performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different processing strategies to different subsets of constellation points based on their local characteristics. The first subset contains points with smaller Euclidean distances and is processed with higher priority and more computational resources, while the second subset contains points with larger distances and is processed with fewer resources. This local quality approach ensures that critical points receive adequate attention while reducing unnecessary computations on less critical points.

Inventive Principle:
Principle #3Local quality

2Reliability

If the value of K is increased to enhance signal receiving performance, then the receiving performance is improved, but the chip processor area is enlarged

Engineering Contradiction:
Improvesignal receiving performanceVSAvoidchip processor area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent implements partial action by not uniformly processing all K preferred points with the same computational effort. Instead, it processes only a portion of the constellation points (those in the first subset with smaller Euclidean distances) with full computational resources, while processing the remaining points (second subset) with reduced resources or skipping them. This partial action approach maintains receiving performance by focusing on the most critical points while reducing the chip processor area required.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If the value of K is increased to enhance signal receiving performance, then the receiving performance is improved, but the power consumption is increased

Engineering Contradiction:
Improvesignal receiving performanceVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent reduces power consumption by performing partial computations on the constellation points. Instead of calculating and processing all K preferred points uniformly, the method selectively processes only the first subset of points with smaller Euclidean distances, which contribute most to the receiving performance. The second subset of points is either processed with reduced computational effort or skipped entirely, significantly reducing power consumption while maintaining acceptable performance levels.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent segments the K preferred points into multiple subsets based on their Euclidean distances, allowing differentiated processing. The first subset (with smaller distances) is processed with full computational resources to ensure high receiving performance, while the second subset (with larger distances) is processed with fewer resources or skipped. This segmentation strategy reduces the total computational load and power consumption while maintaining the critical performance requirements.

Inventive Principle:
Principle #1Segmentation

4Reliability

If the value of K is increased to enhance signal receiving performance, then the receiving performance is improved, but the data processing amount is reduced

Engineering Contradiction:
Improvesignal receiving performanceVSAvoiddata processing amount
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the constellation points into multiple subsets based on their Euclidean distances from the received signal. The first subset contains points with smaller distances and is processed with higher priority, while the second subset contains points with larger distances and is processed with lower priority or skipped. This segmentation reduces the total data processing amount by eliminating unnecessary computations on less critical points while maintaining receiving performance through focused processing of the most important points.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS8238465B2Sphere decoding method applied to multi-input multi-output (MIMO) channel
Publication Date: 2012.08.07 REALTEK SEMICON CORP
  • US8238465B2 patent drawing
  • US8238465B2 patent drawing
  • US8238465B2 patent drawing

AI summary

A sphere decoding method applied to a MIMO channel is provided. Multiple constellation points of an nth detection layer corresponding to a MIMO channel matrix are enumerated based on an enumeration rule, and at least one nth sub-set of the nth detection layer is defined. K constellation points are obtained from each of the at least one nth sub-set as preferred points, and Kn preferred points are selected from all the K preferred points of the at least one nth sub-set. K1 preferred points are transferred to a second detection layer from a first detection layer. K(T−1) preferred points are transferred to a Tth detection layer from a (T−1)th detection layer. An optimal solution is determined according to Kn preferred points of the nth detection layer. K and at least one of K1 to KT are determined by the The characteristic of the MIMO channel matrix.