Dual FEC Streaming Encoding for Packet Loss and Delay Tradeoffs
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Solution Overview
Problem
Existing streaming services face challenges in providing efficient data transmission to users under varying communication conditions, particularly in multicast or broadcast environments where users experience different packet loss rates and types, leading to delays and service disruptions.
Innovation Solution
A method involving dual FEC encoding using FEC 1 and FEC 2 encoders to adaptively adjust FEC block sizes and code rates based on user group conditions, allowing users in good channel conditions to use FEC 1 for fast recovery and those in bad conditions to use FEC 2 for error correction, minimizing delay and maintaining transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the FEC block size N is increased to provide error correction for burst loss, then the transmission reliability is improved, but the service delay increases
Solution Approach 1:
The patent divides the single FEC block into multiple sub-blocks (first sub-block and second sub-block), each processed separately with different code rates. This segmentation allows the system to apply different error correction strengths to different parts of the data, reducing the delay caused by waiting for complete large blocks while maintaining reliability through targeted correction.
Solution Approach 2:
The system dynamically adjusts the code rate for different sub-blocks based on channel conditions. The first sub-block uses a higher code rate for faster decoding, while the second sub-block uses a lower code rate for better error correction. This dynamic adaptation resolves the contradiction by making the FEC block size and code rate flexible rather than fixed.
2Reliability
If the code rate is decreased to provide error correction for users in bad channel conditions, then the transmission reliability is improved, but the transmission efficiency decreases
Solution Approach 1:
The patent applies different code rates to different sub-blocks based on local channel conditions. Users in bad channel conditions receive enhanced error correction on specific sub-blocks, while users in good conditions experience higher overall transmission efficiency. This local differentiation resolves the contradiction by tailoring the error correction strength to specific needs rather than applying uniform low code rates to all data.
Solution Approach 2:
The system changes the code rate parameter for different sub-blocks (first sub-block uses higher code rate, second sub-block uses lower code rate) to adapt to varying channel conditions. This parameter adjustment allows the system to maintain high transmission efficiency for users in good conditions while providing reliable error correction for users in bad conditions.
3Device complexity
If a single FEC block size is used for all users in multicast/broadcast, then the device complexity is reduced, but the adaptability to different channel conditions deteriorates
Solution Approach 1:
The patent segments the FEC block into multiple sub-blocks that can be processed with different code rates. This segmentation maintains relatively simple encoding complexity compared to fully adaptive per-user encoding, while significantly improving adaptability to different channel conditions by allowing differential error correction strategies for different user groups.
Data Source
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AI summary
A method for encoding streaming data according to one embodiment of the present invention comprises: a step of dividing a forward error correction (FEC) source block into one or more FEC sub-blocks; a first encoding step of FEC encoding said one or more FEC sub-blocks; a second encoding step of encoding said FEC source block; and a step of generating third encoded data including first encoded data encoded in the first encoding step and second encoded data encoded in the second encoding step. According to one embodiment of the present invention, a streaming service can be smoothly provided to multiple users in various environments or in a communication environment that varies according to movement or changes in a communication state. Further, a plurality of pieces of parity information can be transmitted to provide a streaming service which is capable of high reliability data recovery.