MODCOD Code Block Filtering for High-Throughput FEC Decoding
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Solution Overview
Problem
In wideband channel DVB-S2 satellite systems, LDPC decoders face high complexity and power consumption due to processing frames not intended for the Very Small Aperture Terminal (VSAT), leading to wastage of throughput and power.
Innovation Solution
Implementing a MODCOD filtering system that uses the current Signal-to-Noise Ratio (SNR) to set a threshold MODCOD range, discarding coded blocks not listed in the MODCOD rank table or outside this range, thereby reducing unnecessary processing and allocating resources to frames intended for the VSAT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the VSAT processes all incoming frames through the LDPC decoder, then all frames can be decoded, but the decoder complexity and power consumption increase excessively
Solution Approach 1:
The patent applies preliminary action by performing MODCOD filtering before the LDPC decoding process. The system pre-identifies and filters out code blocks that cannot be successfully decoded based on MODCOD criteria, so that only potentially decodable blocks are passed to the complex LDPC decoder. This preliminary filtering action prevents the decoder from wasting resources on undecodable frames while maintaining the ability to decode all intended frames.
Solution Approach 2:
The patent extracts and removes code blocks that do not meet the MODCOD criteria from the incoming frame stream before processing. By taking out these unsuitable code blocks early in the process, the system reduces the workload on the LDPC decoder without affecting the decoding of valid frames. This extraction principle directly reduces decoder complexity and power consumption.
2Reliability
If the VSAT processes all incoming frames through the LDPC decoder, then all frames can be decoded, but power consumption increases excessively
Solution Approach 1:
The system performs preliminary MODCOD filtering to identify and exclude undecodable code blocks before they enter the power-intensive LDPC decoding process. This preliminary action ensures that decoder power is only consumed for frames that have a reasonable chance of successful decoding, thereby reducing overall power consumption while maintaining decoding reliability for intended frames.
Solution Approach 2:
The patent discards code blocks that fail the MODCOD criteria before processing, avoiding the waste of power on undecodable frames. By discarding these blocks early, the system recovers power consumption that would have been unnecessarily spent on processing frames that cannot be decoded, while still ensuring all decodable frames are processed.
3Reliability
If the VSAT processes all incoming frames, then no frames are lost, but throughput is wasted on frames not intended for the VSAT
Solution Approach 1:
The system performs preliminary filtering based on MODCOD criteria to identify code blocks that are intended for the VSAT and can be successfully decoded. This preliminary action separates intended frames from unintended ones before processing, ensuring that decoder throughput is dedicated to frames that will actually be used, thereby improving effective productivity without losing intended frames.
Solution Approach 2:
The patent extracts and removes code blocks that do not match the VSAT's intended reception criteria from the processing stream. By taking out these irrelevant code blocks before decoding, the system prevents throughput from being wasted on frames not intended for the VSAT, while maintaining complete processing of all intended frames.
4Reliability
If the VSAT processes all incoming frames, then no frames are lost, but power is wasted on decoding frames not intended for the VSAT
Solution Approach 1:
The system performs preliminary MODCOD filtering to identify and separate frames intended for the VSAT from those not intended. This preliminary action ensures that power consumption is focused only on processing and decoding frames that will be used, eliminating waste of power on unintended frames while maintaining complete processing of all intended frames.
Solution Approach 2:
The patent discards code blocks that are not intended for the VSAT before processing, recovering the power that would have been wasted on decoding these frames. By discarding unintended frames early, the system reduces power consumption while ensuring all intended frames are fully processed and decoded.
Data Source
AI summary
A system and method for filtering code blocks to maintain high throughput thru a Forward Error Correcting (FEC) decoder is disclosed. The method includes: monitoring a Signal-to-Noise Ratio (SNR) for an incoming link; selecting a rank table including a rank, Modulation and Coding Rate (MODCOD), and a minimum SNR; determining a threshold MODCOD range from the rank table based on the SNR; demodulating an incoming frame; identifying, in the incoming frame, the code blocks and an associated MODCOD for each of the code blocks; selecting a code block from the code blocks when the respective MODCOD for the code block is in the rank table and within the threshold MODCOD range; and decoding the selected code block with the associated MODCOD.