BP Equalization via QR Decomposition for Massive MIMO Detection

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Solution Overview

Problem

The BP equalization algorithm faces challenges with high overhead and limited application scenarios due to its complexity and suitability issues in multi-user detection, particularly in Massive MIMO scenarios.

Innovation Solution

The method involves splitting received signals and channel estimations into real and imaginary parts, performing QR decomposition on the channel estimation matrix to reduce dimensionality, and iterating based on the resulting equivalent signals and noise power to obtain symbol position probabilities, thereby reducing computation overhead and expanding application scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If BP equalization algorithm is implemented using traditional FG-GAI or CHEMP methods, then symbol estimation accuracy is improved, but computational overhead increases and application scenarios are limited

Engineering Contradiction:
Improvesymbol estimation accuracyVSAvoidcomputational overhead
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the complex-valued equalization problem into two independent real-valued problems by separating real and imaginary parts of the channel matrix H into Hr and Hi. This segmentation allows each part to be processed independently through QR decomposition, reducing the overall computational complexity while maintaining estimation accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the problem from complex domain to real domain by changing the parameter representation. Instead of performing operations on complex matrices directly, the method uses real and imaginary parts separately, which changes the mathematical parameters and reduces computational overhead while preserving the essential signal characteristics.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If BP equalization algorithm is implemented using traditional methods, then performance is improved, but implementation complexity increases due to large matrix operations

Engineering Contradiction:
Improveequalization performanceVSAvoidimplementation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the large complex channel matrix H into smaller real matrices Hr and Hi through segmentation. This allows QR decomposition to be performed on smaller real-valued matrices rather than one large complex matrix, reducing memory requirements and computational steps while maintaining the reliability of the equalization process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces complex arithmetic operations with real arithmetic operations. By substituting complex matrix operations with equivalent real matrix operations, the implementation becomes simpler and more efficient, as real arithmetic is computationally less intensive and easier to implement in practical systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of information

If QR decomposition is performed on full channel matrix H, then complete channel information is preserved, but computational cost increases

Engineering Contradiction:
Improvechannel information preservationVSAvoidcomputational cost
Core Design Contradiction:
Loss of informationVSUse of energy by moving object

Solution Approach 1:

The patent segments the channel matrix H into real part Hr and imaginary part Hi, allowing QR decomposition to be performed separately on each segment. This segmentation preserves all channel information while distributing the computational load across two smaller operations rather than one large operation, thereby reducing overall computational cost.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs QR decomposition on the real and imaginary parts separately rather than on the complete complex matrix at once. This partial action approach processes the channel information in manageable segments, reducing the immediate computational burden while still capturing all necessary channel characteristics through the combined processing of Hr and Hi.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS11979260B2BP equalization method, device, communication apparatus and storage medium
Publication Date: 2024.05.07 XIAN ZHONGXING NEW SOFTWARE
  • US11979260B2 patent drawing
  • US11979260B2 patent drawing
  • US11979260B2 patent drawing

AI summary

A Belief Propagation (BP) equalization method and apparatus, a communication device and a storage medium are disclosed. The method may include: splitting a received signal Yc, a channel estimation Hc and a symbol estimation Xc into real parts and imaginary parts to obtain a received signal matrix Y, a channel estimation matrix H and a symbol estimation matrix X (S101); performing orthogonal triangular (QR) decomposition on the channel estimation matrix H to obtain an equivalent received signal Ybp, an equivalent channel R and a noise power σ2 (S102); and performing iteration based on the equivalent received signal Ybp, the equivalent channel R and the noise power σ2 to obtain a position probability of per stream symbol (S103).