Contrast Coding for Bit-Subset BER Control in FEC
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Solution Overview
Problem
Existing communication systems face challenges in efficiently managing bit error rates (BER) across different bits due to varying channel qualities, leading to suboptimal performance in error correction and increased overhead in Forward Error Correction (FEC) schemes.
Innovation Solution
The implementation of contrast coding, which adjusts bit error rates (BER) through contrast encoding at the transmitter and contrast decoding at the receiver, allowing for better matching of BERs with FEC schemes and modulation formats, thereby enhancing noise tolerance, data capacity, or reducing system size and heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stronger FEC schemes are used to provide better error protection, then reliability is improved, but information rate decreases and device complexity increases
Solution Approach 1:
The patent divides the set of information bits into multiple subsets, where each subset is encoded with a different FEC scheme having distinct information rates. This segmentation allows different reliability levels to be applied to different bit groups, improving overall error protection while maintaining higher average information rate compared to using a single strong FEC scheme for all bits.
Solution Approach 2:
The patent applies different FEC encoding strengths to different subsets of bits based on their individual error susceptibility. Bits that are more prone to errors receive stronger FEC protection, while less susceptible bits use weaker FEC schemes. This local differentiation optimizes the balance between reliability and information rate by avoiding over-protection of robust bits.
2Reliability
If stronger FEC schemes are used to provide better error protection, then reliability is improved, but device complexity increases
Solution Approach 1:
By segmenting bits into subsets with different error characteristics and applying appropriately-strengthed FEC schemes to each, the patent avoids the need to implement extremely strong FEC across the entire data set. This reduces the overall complexity of FEC circuitry while achieving comparable or superior effective error protection.
3Productivity
If modulation format maps bits to symbols differently, then data capacity is improved, but bit error rates become unequal across bit subsets
Solution Approach 1:
The patent addresses the non-uniform BER caused by modulation formats by applying different FEC encoding strengths to different bit subsets. Bits that experience higher error rates due to their position in the modulation scheme receive stronger protection, while bits with lower error rates use weaker FEC. This local adaptation maintains the benefits of the modulation format's high data capacity while compensating for its BER non-uniformity.
Data Source
AI summary
In data communications, a suitably designed contrast coding scheme, comprising a process of contrast encoding at a transmitter end and a process of contrast decoding at a receiver end, may be used to adjust the contrast in bit error rate (BER) experienced by different classes of bits. Contrast coding may be used to tune the BERs experienced by different subsets of bits, relative to each other, to better match a plurality of forward error correction (FEC) schemes used for transmission of information bits, which may ultimately provide a communications system having a higher noise tolerance, or greater data capacity, or smaller size, or lower heat.