Sequential Decoder Metric Adjustment for Anticipated Termination

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Solution Overview

Problem

Existing sequential decoding methods in wireless communication systems face challenges with high computational complexity, especially when dealing with increasing constellation sizes and the number of antennas, leading to suboptimal performance due to early termination of decoding processes in systems with limited hardware resources.

Innovation Solution

A sequential decoder is introduced that includes a symbol estimation unit using best-first tree search and a termination alarm monitoring unit, which reduces the weight metric of decoding tree nodes in response to triggered termination alarms, allowing for anticipated termination while maintaining optimal performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If sequential decoding methods are used to reduce computational complexity, then decoding complexity is reduced, but decoding performance deteriorates due to early termination

Engineering Contradiction:
Improvedecoding complexityVSAvoiddecoding performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies preliminary action by anticipating termination before it actually occurs. The termination alarm is triggered when a threshold condition is met, and the decoder prepares alternative paths in advance by storing multiple candidate paths in a stack. This allows the decoder to switch to alternative paths proactively rather than reactively, maintaining performance while enabling early termination.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If early termination is implemented to improve throughput, then productivity increases, but decoding performance deteriorates

Engineering Contradiction:
ImprovethroughputVSAvoiddecoding performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent prepares alternative decoding paths in advance by maintaining a stack of candidate paths. When termination is anticipated, the decoder can immediately switch to pre-prepared alternative paths without additional computation, thus improving throughput while maintaining performance through proactive preparation.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If the decoding search space is limited to reduce complexity, then computational complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvecomputational complexityVSAvoidsignal estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent computes metric values for multiple candidate paths in advance and stores them in a stack. When termination is anticipated, the decoder can immediately select from pre-computed alternative paths with known metric values, avoiding the need for additional computations while maintaining estimation accuracy through proactive preparation of multiple candidates.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3104564B1Anticipated termination for sequential decoders
Publication Date: 2020.05.06 INSTITUT MINES TELECOM TELECOM BRETAGNE
  • EP3104564B1 patent drawingFigure 1
  • EP3104564B1 patent drawingFigure 2
  • EP3104564B1 patent drawingFigure 3

AI summary

There is provided a decoder for decoding a data signal received through a transmission channel in a communication system, the decoder (310) comprising a symbol estimation unit (311) configured to determine estimated symbols representative of the transmitted symbols carried by the received signal, the estimated symbols being determined from nodes of a decoding tree based on a weight metric associated with each of the node. The decoder further comprises a termination alarm monitoring unit (312) for monitoring a termination alarm depending on the current decoding computation complexity, the termination alarm being associated with a metric parameter, the symbol estimation unit being configured to reduce the weight metric of each node of the decoding tree by a quantity corresponding to a function of the metric parameter associated with the termination alarm, in response to the triggering of the termination alarm.