Joint Fountain-Network Coding for Multihop Packet Loss Recovery
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Solution Overview
Problem
Existing network coding methods face challenges in achieving high data throughput and low transmission delay, especially in multihop wireless networks, due to packet loss and erasure channels, where traditional approaches like ARQ and FEC have limitations in adapting to varying channel conditions and requiring feedback.
Innovation Solution
The implementation of Joint Fountain coding and Network coding (FUN), where each source node uses a fountain code, and intermediate nodes perform intra-session and cross-next-hop network coding, allowing the sink node to decode and reconstruct native packets with a sufficient number of coded packets, dynamically adjusting to channel conditions without the need for feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fountain coding is used at source nodes and network coding at intermediate nodes, then data throughput increases and transmission delay decreases, but system complexity increases due to multiple coding layers
Solution Approach 1:
The coding system is segmented into two distinct layers: fountain coding at source nodes and network coding at intermediate nodes. This segmentation allows each layer to perform its specific function independently, with fountain coding generating redundant packets and network coding combining packets from multiple sources, thereby increasing throughput without requiring the entire system to handle all coding operations centrally
Solution Approach 2:
The patent combines fountain coding and network coding into a unified joint coding system where the outputs of fountain coding are fed into network coding operations at intermediate nodes. This merging allows the benefits of both coding schemes to be realized simultaneously, achieving higher data throughput and lower transmission delay while managing complexity through modular integration
2Reliability
If traditional ARQ is used for packet loss recovery, then reliability improves through retransmission, but feedback implosion problem occurs in multicast scenarios
Solution Approach 1:
The patent extracts the feedback mechanism from the packet loss recovery process by using forward error correction through fountain coding instead of retransmission-based ARQ. This extraction eliminates the feedback implosion problem in multicast scenarios while maintaining reliability through the generation of redundant coded packets that can be decoded without feedback
Solution Approach 2:
Fountain coding acts as an intermediary between the source and destination nodes, providing error correction capability without requiring direct feedback communication. The coded packets generated by fountain coding serve as a mediator that carries redundancy information forward, enabling reliable packet loss recovery while avoiding the feedback complexity that plagues traditional ARQ in multicast
3Ease of manufacture
If FEC with fixed code rate is used, then implementation simplicity improves, but adaptability to varying channel conditions deteriorates
Solution Approach 1:
The patent introduces dynamics into the coding system through fountain coding, which generates packets with varying redundancy levels. Unlike fixed-rate FEC, the fountain coding mechanism dynamically adjusts the amount of redundancy provided based on channel conditions and packet loss patterns, allowing the system to adapt to varying channel conditions while maintaining implementation simplicity through a unified coding approach
Data Source
AI summary
A network system for increasing data throughput and decreasing transmission delay from a source node to a sink node via a relay node. The network system may comprise a source node configured to encode a plurality of data packets using rateless coding and transmit the plurality of data packets; at least one relay node configured to receive at least one of the plurality of data packets from the source node, and if the at least one relay node has received a sufficient quantity of the plurality of data packets, regenerate, re-encode, and relay the plurality of data packets; and a sink node configured to receive one or more of the plurality of data packets from the at least one relay node, and if the sink node has received the sufficient quantity of the plurality of data packets, regenerate and decode the plurality of data packets.