Soft-Demodulation Relay Coding for Long-Distance Link Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional communication systems face reduced communication reliability due to insufficient correction capability in error-correction encoding when transmission distances are long, particularly in scenarios like transmission from the Moon to an artificial satellite orbiting Earth, where error occurrence is high.
Innovation Solution
A relay device performs soft demodulation to generate a soft demodulated sequence with reliability information, followed by second error-correction encoding and modulation, without requiring a soft-decision decoding circuit, thus maintaining communication reliability and reducing circuit scale and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If error-correction encoding premised on hard-decision decoding is used at relay devices, then device complexity is reduced, but communication reliability deteriorates when transmission distance is long
Solution Approach 1:
The patent changes the decoding parameter from hard-decision to soft-decision at the relay device. By using soft demodulation that generates reliability information (soft values) instead of hard decisions, the system maintains high communication reliability over long distances while keeping the relay device complexity manageable through selective application of soft-decision processing only at the relay stage
Solution Approach 2:
The relay device acts as an intermediary that performs soft demodulation and generates soft demodulated sequences with reliability information. This intermediary processing allows the transmission device's hard-decision encoded signal to be transformed into a form suitable for the reception device's soft-decision decoding, bridging the gap between simple transmission encoding and reliable reception decoding
2Reliability
If soft-decision decoding is used at the final relay device, then communication reliability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent applies soft-decision processing locally only at the final relay device rather than at all relay devices. The configuration specifies that among multiple relay devices, only the final one performs soft demodulation and generates soft demodulated sequences, while intermediate relay devices use simpler hard-decision encoding. This localized application of complex processing reduces overall system complexity while maintaining reliability where it matters most
Solution Approach 2:
The system applies soft-decision processing partially - only at the final relay device and reception device, rather than throughout the entire transmission chain. This partial application of the more complex soft-decision methodology provides sufficient error correction capability for long-distance communication without requiring all relay devices to implement the full soft-decision complexity
Data Source
AI summary
A relay device performs signal relay between a transmission device that transmits a first modulated signal obtained by modulating a first error-correction code sequence generated by performing a first error-correction encoding process on an information sequence and a reception device serving as a destination of the first modulated signal. The relay device includes a first soft demodulator that generates a first soft demodulated sequence including reliability information corresponding to the first modulated signal; a second error-correction encoder that performs a second error-correction encoding process on an information sequence including the first soft demodulated sequence to generate a second error-correction code sequence; and a second modulator that transmits a second modulated signal obtained by modulating the second error-correction code sequence.