Shifted Interleaving FEC Encoding for Bandwidth and Complexity Trade-offs
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Solution Overview
Problem
Existing encoding methods for data streams in communication systems, such as satellite broadcasts, face inefficiencies due to increased computational requirements and synchronized decoding of multiple shares, which can overwhelm devices with limited resources and result in suboptimal error correction and bandwidth management.
Innovation Solution
The method introduces a time-shifted interleaving scheme where shares of packet-level FEC encoded packets are transmitted with a defined time shift, allowing for increased shares per lot without proportional increases in computational complexity, and ensures uniform distribution of error-correcting wildcard packets, improving robustness and bandwidth management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple shares of packet-level FEC encoded packets are transmitted simultaneously, then bandwidth utilization improves, but decoding complexity increases proportionally
Solution Approach 1:
The patent divides the transmitted packet stream into multiple shares, where each share contains a subset of source packets and corresponding wildcard packets. This segmentation allows the receiver to decode shares independently and in parallel, reducing the computational burden on decoding devices while maintaining high bandwidth utilization through simultaneous transmission of multiple shares
Solution Approach 2:
The patent performs preliminary FEC encoding at the transmitter to generate wildcard packets that contain error-correction contributions from multiple source packets. These wildcard packets are prepared in advance and distributed across different shares, enabling receivers to reconstruct source packets without performing complex real-time computations, thus reducing decoding complexity while maintaining high transmission efficiency
2Reliability
If more wildcard packets are transmitted for error correction, then reliability improves, but bandwidth consumption increases
Solution Approach 1:
The patent dynamically adjusts the number and distribution of wildcard packets based on channel conditions and reliability requirements. By modifying the parameters of FEC encoding (such as the ratio of wildcard to source packets and their distribution across shares), the system achieves improved error correction capability while optimizing bandwidth consumption to avoid unnecessary overhead
3Ease of operation
If synchronous decoding of multiple shares is implemented, then decoding simplicity improves, but device resource requirements increase
Solution Approach 1:
The patent segments the overall decoding task into independent share-level decoding operations. Each share can be decoded separately using the same decoding algorithm, allowing receivers with limited resources to process one share at a time rather than requiring simultaneous processing of all shares, thus reducing device resource requirements while maintaining decoding simplicity through algorithmic consistency across shares
Data Source
AI summary
A method for transmitting interleaved shares of packet-level FEC encoded packets, in which a given time shift occurs between consecutive shares, includes determining a current state; associating a packet with a share based on the current state; and determining a position of the packet within the share. Each share includes source packets and error-correcting or wildcard packets. If the position of the packet corresponds to a source packet position, a contribution of the packet to the wildcard packets of the share is computed, and the packet is transmitted as a source packet. If the position of the packet corresponds to a wildcard packet position, the packet is transmitted as a wildcard packet.