Cross Layer Coding for Satellite Mobile TV Broadcast
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Solution Overview
Problem
Satellite-based mobile TV broadcasting experiences signal loss due to long shadowing, degrading user experience and requiring retransmissions, which existing technologies struggle to handle effectively in broadcast/multicast services without wasting bandwidth.
Innovation Solution
The implementation of orthogonal multiple description codes (OMDC) for encoding multimedia content, which provides error protection by generating multiple descriptions of video streams with redundancy, allowing for error detection and correction without additional bandwidth, and improving video quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If satellite broadcast is used for mobile TV, then bandwidth efficiency is improved, but signal reliability deteriorates due to long shadowing
Solution Approach 1:
The video stream is segmented into multiple descriptions (first description and second description) using OMDC encoding. Each description can be independently decoded to provide the video service, allowing the system to transmit only essential information in each stream while maintaining overall video quality through combination, thus improving bandwidth efficiency while ensuring reliability against shadowing effects
Solution Approach 2:
The system changes the encoding parameters by applying different coding protocols (e.g., H.264 for first description, H.265 for second description) to different video descriptions. This allows optimization of each stream's parameters for specific channel conditions, improving both bandwidth efficiency and signal reliability under varying shadowing conditions
2Reliability
If retransmissions are implemented to handle signal loss, then signal reliability is improved, but bandwidth efficiency deteriorates
Solution Approach 1:
The system performs preliminary error protection by encoding multiple descriptions with forward error correction capabilities before transmission. This preliminary action ensures that receivers can recover from signal loss without requiring retransmissions, maintaining both reliability and bandwidth efficiency
Solution Approach 2:
The system creates redundant copies of video information through multiple descriptions generated by OMDC. These copies contain complementary information that enables error recovery without exact duplication, providing reliability while minimizing the bandwidth overhead compared to traditional retransmission approaches
3Manufacturing precision
If multiple coding protocols are used for different video streams, then video quality is improved, but system complexity increases
Solution Approach 1:
The complex encoding task is segmented into multiple independent description streams, each processed with appropriate coding protocols. This segmentation allows parallel processing and independent optimization of each stream's quality without increasing overall system complexity, as each segment can be handled separately through standardized interfaces
Data Source
AI summary
Methods and apparatus providing error protection in multicast-broadcast service by encoding multimedia content according to a first protocol to provide a plurality of distinct video streams, coding each of the distinct video streams using respective coding protocols, wherein each coding protocol has associated with it corresponding descriptors and coefficients, and multiplexing the coded video streams toward a wireless network.