Fountain Code Relaying with Degree-Constrained Packet Combining
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Solution Overview
Problem
In vehicular communication systems, existing technologies face challenges with high decoding complexity in relaying fountain codes, particularly in dynamic topologies with unpredictable erasures and lack of acknowledgments, limiting their applicability for large-scale content delivery.
Innovation Solution
A method involving degree reduction and degree-constrained combining of packets using low-complexity algorithms, where intermediate vehicles reduce the degree of received packets and combine them based on weights to satisfy the degree distribution of the fountain code, enabling efficient relaying with low computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fountain codes are relayed using existing technologies in vehicular communication systems, then content delivery can be achieved, but decoding complexity becomes high
Solution Approach 1:
The patent segments the fountain code relaying process into two distinct phases: encoding phase where intermediate vehicles perform simple degree reduction and combining operations, and decoding phase where destination vehicles decode received packets. This segmentation shifts computational complexity from relay nodes to destination nodes, enabling low-complexity relaying while maintaining content delivery efficiency
Solution Approach 2:
The patent changes the parameter of packet degree distribution by introducing degree reduction techniques. Instead of relaying packets with original high degrees that require complex decoding, the system transforms packets to have reduced degrees through combining operations, thereby simplifying the decoding process and reducing overall system complexity while preserving delivery capability
2Reliability
If fountain codes are relayed in dynamic topologies with unpredictable erasures, then communication robustness is achieved, but computational complexity increases
Solution Approach 1:
The patent applies preliminary action by having intermediate vehicles perform degree reduction and packet combining operations before relaying. This preliminary processing prepares packets in advance with optimized degree distributions, so that when packets reach destination vehicles, the decoding process is simplified. This advance preparation maintains reliability in dynamic topologies while reducing the computational burden during actual decoding
Solution Approach 2:
The patent introduces an intermediary processing step at relay vehicles that acts as a mediator between source and destination. The intermediary performs degree-constrained combining operations on received packets, transforming them into a form that is more suitable for final decoding. This intermediary processing layer handles the complexity of dealing with erasures and dynamic topologies, shielding destination nodes from these challenges while maintaining communication reliability
Data Source
AI summary
A method, an apparatus, and a computer program product for relaying a packet are provided. The apparatus receives at least one packet and reduces a degree of the at least one packet. The apparatus further processes the at least one packet based on the reduced degree, generates a combined packet by combining the at least one processed packet with at least one other processed packet based on the reduced degree and a weight of each of the processed packets, and transmits the combined packet.