TCM/BCM Decoder Branch Metrics Using Nearest-Neighbor Test Sets

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Solution Overview

Problem

Current communication systems employing trellis coded modulation (TCM) or block coded modulation (BCM) require significant resources for decoding due to complex computations and large silicon area, making them inefficient in processing received signal vectors.

Innovation Solution

A method is introduced to efficiently decode signal vectors by forming a set of most likely vectors and using these to decode, rather than considering all possible interpretations, thereby reducing resource consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional TCM/BCM decoding is performed by considering every possible interpretation of the received signal vector, then decoding accuracy is maintained, but processing complexity and resource consumption increase significantly

Engineering Contradiction:
Improvedecoding accuracyVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the set of all possible signal vector interpretations into two parts: a small subset of most likely vectors and the remaining less likely vectors. The decoder focuses computational resources only on evaluating the most likely vectors, while treating less likely vectors as negligible. This segmentation allows the system to maintain high decoding accuracy by considering the dominant probability mass without the computational burden of evaluating every possible interpretation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by considering only a portion (the most likely vectors) of all possible interpretations rather than exhaustively evaluating every possibility. By identifying and focusing on the subset of vectors that contribute most significantly to the decoding decision, the system achieves near-optimal performance with substantially reduced computational complexity.

Inventive Principle:
Principle #16Partial or excessive action

2Reliability

If conventional TCM/BCM decoding processes all possible signal vector interpretations, then complete data recovery is achieved, but silicon area and processing power requirements become prohibitively large

Engineering Contradiction:
Improvedata recovery completenessVSAvoidsilicon area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent segments the computational workload by identifying a small set of most likely signal vectors that account for the vast majority of decoding decisions. The hardware implementation only needs to evaluate these segmented vectors, dramatically reducing the silicon area required for the decoder while maintaining complete and accurate data recovery for practical communication scenarios.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the essential decoding information by identifying and isolating the most likely signal vectors from the complete set of possible interpretations. By taking out only the critical subset of vectors that determine decoding outcomes, the system achieves complete data recovery with minimal hardware resources.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If the number of signal constellation points is increased to transmit more information per symbol period, then throughput is improved, but the complexity of the detector/decoder increases

Engineering Contradiction:
ImprovethroughputVSAvoiddetector complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the large signal constellation into a manageable subset of most likely vectors based on received signal characteristics. Even as the overall constellation size increases to improve throughput, the detector only needs to evaluate the segmented subset, preventing detector complexity from scaling linearly with constellation size and enabling high-throughput systems with manageable complexity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS8612837B1BM/LLR computations for multi-dimensional TCM/BCM codes
Publication Date: 2013.12.17 MARVELL ASIA PTE LTD
  • US8612837B1 patent drawing
  • US8612837B1 patent drawing
  • US8612837B1 patent drawing

AI summary

Systems and methods for processing and decoding TCM/BCM-coded signal vectors. A multi-dimensional signal vector is received by, for example, a TCM or BCM decoder. The TCM/BCM decoder identifies the closest signal points in the signal constellation set, or “nearest neighbors,” for each dimension of the received signal vector. The TCM/BCM decoder then forms a test set that includes a plurality of multi-dimensional test vectors, where each dimension of each test vector is based on an identified nearest neighbor. In particular, each test point in the test set is based on a different combination of the nearest neighbors. The TCM/BCM decoder can compute branch metrics based on only the test points in the test set, and can make detection decisions using the computed branch metrics.