Outer FEC Coding with Reed-Solomon for TD-SCDMA Broadcast BER
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Solution Overview
Problem
Current TD-SCDMA network configurations are not suitable for mobile broadcast services like mobile TV due to high bit error rates (BER) between 10−4 and 10−5, which need to be reduced to 10−8 to 10−9 for reliable transmission.
Innovation Solution
An outer Forward Error Correcting (FEC) coding system is introduced, utilizing Reed-Solomon encoding and convolutional interleaving to encode and randomize data, followed by transport channel multiplexing, specifically using the Reed-Solomon (204, 188, t=8) code and convolutional interleaving to achieve lower BER.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TD-SCDMA network configuration is used, then network compatibility and existing infrastructure are maintained, but bit error rate remains too high (10^-4 to 10^-5) for reliable mobile broadcast transmission
Solution Approach 1:
The patent applies segmentation by dividing the error correction task into two distinct stages: inner FEC coding (convolutional code) for basic error protection, and outer FEC coding (Reed-Solomon code) for additional error correction. This segmented approach allows each coding stage to specialize in different error types, achieving the required BER of 10^-8 to 10^-9 while maintaining systematic implementation on existing TD-SCDMA infrastructure
Solution Approach 2:
The patent employs composite coding by combining Reed-Solomon outer FEC code with convolutional inner FEC code. This composite error correction system leverages the strengths of both coding schemes: Reed-Solomon excels at correcting burst errors while convolutional code provides continuous error protection. The combination achieves the required transmission reliability for mobile broadcast services without requiring complete system replacement
2Reliability
If outer FEC coding with Reed-Solomon and convolutional interleaving is added, then bit error rate is reduced to required levels (10^-8 to 10^-9), but system complexity and processing overhead increase
Solution Approach 1:
The patent applies preliminary action through convolutional interleaving performed before outer Reed-Solomon encoding. The interleaver redistributes data symbols to break up burst error patterns before they reach the outer FEC decoder. This preliminary processing prepares the data in an optimal state for Reed-Solomon correction, reducing the computational burden on the outer decoder and improving overall system efficiency
Solution Approach 2:
The patent introduces convolutional interleaving as an intermediary component between the inner and outer FEC coding stages. This intermediary element transforms the error pattern from burst-like to more random distribution, making the errors more amenable to correction by the outer Reed-Solomon code. The interleaver acts as a mediator that optimizes the error characteristics for the subsequent correction stage
Data Source
AI summary
An apparatus and method of an outer Forward Error Correcting (FEC) code for a mobile broadcast service based on TD-SCDMA network is disclosed.