Tree Decoding Path Metrics for Lower-Complexity Block Code Search
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Solution Overview
Problem
Current tree decoding methods for linear block codes face high decoding complexity, especially when dealing with longer codes, which is exacerbated by the need for exhaustive search and complex path metric calculations.
Innovation Solution
The proposed method reduces decoding complexity by estimating the path metric of nodes using a combination of the actual path metric and an estimated accumulated edge metric, allowing for the early elimination of nodes with inferior metrics, and incorporating parity bit metrics into information bit metrics to minimize the search range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exhaustive search decoding mode is adopted to decode linear block codes, then all possible paths can be evaluated to ensure optimal decoding accuracy, but the calculation complexity exponentially increases with the number of information bits
Solution Approach 1:
The patent performs preliminary action by calculating and storing the metrics of parity bits in advance before the actual decoding process. The parity bit metrics are pre-computed based on the received signal and the generator matrix, allowing these values to be readily available during tree traversal without requiring recalculation at each node, thus reducing real-time computational complexity
Solution Approach 2:
The patent applies partial action by using a finite stack with limited size to store only the most promising paths during decoding. Instead of evaluating all 2^k paths exhaustively, the algorithm maintains a limited number of best paths in the stack, performing partial evaluation that balances decoding accuracy with reduced computational complexity
2Reliability
If the stack size is increased to improve decoding accuracy, then more paths can be evaluated, but the memory requirements and processing overhead increase
Solution Approach 1:
The patent changes the parameter of stack size from a large or unlimited value to a optimized finite value. By adjusting this parameter to an optimal level, the system achieves good bit error rate performance while constraining memory usage. The finite stack size parameter is chosen to balance between evaluation thoroughness and resource consumption
3Measurement precision
If all parity bit metrics are calculated independently during decoding, then complete path metrics can be obtained, but the decoding process becomes more time-consuming
Solution Approach 1:
The patent merges the calculation of parity bit metrics into the information bit processing flow. Instead of calculating parity metrics separately, the algorithm combines them during the tree traversal process, utilizing the pre-computed parity metrics and integrating them with information bit metrics to form complete path metrics efficiently
Data Source
AI summary
A tree decoding method for decoding a linear block code is provided. According to the tree decoding method, an estimated path metric of node v is f(v)=g(v)+h(v), where g(v) represents a sum of bit metrics of all bits on a path from the root node to the node v, and h(v) represents a lowest bound of estimated accumulated bit metrics from the node v to the goal node. The present invention creatively improves the approach for calculating h(v). According to the present invention, some parity bits are only related to a part of the information bits, according to which the edge metric h(v) of the parity bits can be preliminarily incorporated into the path metric of the part of the information bits. As such, some nodes having inferior path metric could be eliminated in advance, thus minimizing the searching range and simplifying the decoding complexity.