Turbo Decoding with Boundary Value Inheritance for High Code Rates
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Solution Overview
Problem
Current MAP decoding schemes face performance degradation and complexity under high code rates due to the need for pre-calculating overlap values, leading to low effective decoding time for sub-blocks in Turbo code systems.
Innovation Solution
The proposed method employs an MAP algorithm-based Turbo decoding approach that iteratively estimates information symbols by using window and block boundary value inheritance, eliminating the need for pre-calculating initial states, and utilizes a ping-pong operation in a RAM array to calculate posterior probability LLR values, thereby simplifying the implementation and extending effective decoding time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-calculating overlap values is used to obtain accurate boundary values, then decoding accuracy is improved, but implementation complexity increases and effective decoding time decreases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing α and β boundary values for overlapping regions before the main decoding process. This allows the decoder to quickly retrieve accurate boundary values without performing complex real-time calculations, thus maintaining high boundary value accuracy while reducing implementation complexity and increasing effective decoding time.
2Measurement precision
If pre-calculating overlap values is used to obtain accurate boundary values, then decoding accuracy is improved, but effective decoding time of each sub-block decreases
Solution Approach 1:
The patent performs the time-consuming boundary value calculations in advance and stores them in memory. During the actual decoding of each sub-block, the pre-calculated boundary values are simply retrieved and applied, which maintains high boundary value accuracy while significantly increasing the effective decoding time available for processing actual data.
3Reliability
If iterative decoding with feedback is used to approach channel capacity, then decoding performance is improved, but decoding delay increases
Solution Approach 1:
The patent segments the decoding process into parallel sub-blocks that can be processed independently with inherited boundary values. This segmentation allows iterative decoding to be applied to smaller units simultaneously, maintaining high decoding performance through multiple iterations while reducing overall decoding delay through parallel processing.
Solution Approach 2:
By pre-calculating boundary values before the iterative decoding process, the patent eliminates the need to perform boundary calculations during each iteration. This allows the iterative decoding algorithm to focus solely on the core decoding operations, maintaining high reliability through sufficient iterations while minimizing the time lost to boundary value computations.
Data Source
AI summary
An MAP algorithm-based Turbo decoding method and apparatus. The method includes: iteratively estimating an information symbol by using an MAP algorithm, acquiring an α and β window boundary values of each sliding window by means of window boundary value inheritance, acquiring an α block boundary value and β block boundary value of each sub-block by means of block boundary value inheritance, and recursively calculating posterior probability Log Likelihood Ratio (LLR) values of a whole window and a whole block according to the α boundary values and the β boundary values (101); and performing decoding decision according to the LLR values (102).