Sphere Decoding for MIMO Signal Detection Complexity Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The complexity of signal detection in multi-input multi-output (MIMO) systems increases significantly with the need for higher signal receiving performance, leading to increased system complexity, chip processor area, and power consumption, especially in high-order MIMO systems with insufficient orthogonal characteristics.

Innovation Solution

The sphere decoding method uses the Schnorr & Euchner enumeration rule and linking-list schemes to reduce detection complexity by selectively calculating partial Euclidean distances and updating subsets of constellation points, thereby obtaining preferred points with reduced computational overhead.

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 by a multiple of (T−2)×M

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

Solution Approach 1:

The patent divides the detection process into T detection layers, where each layer processes a subset of the total K preferred points. Specifically, each detection layer processes only (T-1) preferred points from the previous layer, segmenting the overall computational task to reduce the complexity multiplier from (T-2)×M to a manageable level while maintaining the total K preferred points across all layers for high receiving performance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different processing strategies to different detection layers. The first detection layer processes K preferred points to obtain (T-1) preferred points, while subsequent layers process only (T-1) preferred points each. This local differentiation optimizes the computational load distribution across layers, reducing overall system complexity while preserving signal receiving performance

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 area of the chip processor is enlarged

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

Solution Approach 1:

The patent segments the preferred point processing across T detection layers, where each layer handles a reduced subset of (T-1) preferred points instead of the full K points. This segmentation reduces the computational burden on individual processor units, thereby reducing the required chip processor area while maintaining the overall K preferred points necessary for high signal receiving performance

Inventive Principle:
Principle #1Segmentation

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 segments the computational workload across T detection layers, with each layer processing only (T-1) preferred points from the previous layer. This segmentation reduces the total number of partial Euclidean distance calculations and sorting operations required per detection layer, thereby reducing power consumption while maintaining the overall K preferred points necessary for high signal receiving performance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by processing only a subset of preferred points at each detection layer beyond the first layer. Instead of processing all K preferred points at every layer, each subsequent layer processes only (T-1) preferred points, reducing computational overhead and power consumption while still achieving the necessary receiving performance through the cumulative effect across all T layers

Inventive Principle:
Principle #16Partial or excessive action

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 data processing task across T detection layers, where each layer processes a reduced subset of preferred points. The first layer processes K preferred points to obtain (T-1) preferred points, and subsequent layers process only (T-1) preferred points each. This segmentation increases the effective data processing amount by distributing work efficiently, thereby improving productivity while maintaining high signal receiving performance through the cumulative K preferred points

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS8184735B2Sphere decoding method applied to multi-input multi-output (MIMO) channel
Publication Date: 2012.05.22 REALTEK SEMICON CORP
  • US8184735B2 patent drawing
  • US8184735B2 patent drawing
  • US8184735B2 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 the MIMO channel matrix are enumerated based on an enumeration rule, and at least one nth sub-set of the nth detection layer is defined. The constellation point with the least PED is obtained as a preferred point. Another constellation, not in the nth sub-set, of the nth detection layer is selected to substitute for the preferred point as one of the nth sub-set. If other preferred points are needed to be obtained, the nth sub-set is updated repeatedly according to the least PED. An optimal solution is determined according to Kn preferred points of the nth detection layer.