Moving Window Network Coding in Cooperative Multicast (v1)

TL;DR

This paper introduces MWNCast, a moving window network coding protocol for cooperative multicast in wireless networks, which improves throughput, reduces delay, and lowers complexity without explicit feedback.

Contribution

The paper proposes a novel moving window network coding scheme that approaches capacity, reduces decoding delay, and maintains linear decoding complexity without relying on feedback.

Findings

MWNCast approaches cooperative capacity with exponential packet loss reduction.

Decoding delay is on the order of O(1/(1-ρ)^2).

Decoding complexity is linear, O(W), with respect to window size.

Abstract

Cooperative multicast is an effective solution to address the bottleneck problem of single-hop broadcast in wireless networks. By incorporating with the random linear network coding technique, the existing schemes can reduce the retransmission overhead significantly. However, the receivers may incur large decoding delay and complexity due to the batch decoding scheme. In addition, the dependency on the explicit feedback leads to scalability problem in larger networks. In this paper, a cooperative multicast protocol named MWNCast is proposed based on a novel moving window network coding technique. We prove three properties of the proposed scheme. Firstly, without explicit feedback, MWNCast can approach the cooperative capacity with the packet loss probability dropping almost exponentially with the increase of window size. Secondly, the average decoding delay of a receiver is on the order of $O(\frac{1}{(1-\rho)^2})$ with respect to its traffic intensity $\rho$. Thirdly, MWNCast can achieve the linear decoding complexity of $O(W)$ with respect to the window size $W$. Simulation results show that MWNCast outperforms the existing schemes by achieving better tradeoff between the throughput and decoding delay, meanwhile keeping the packet loss probability and decoding complexity at a very low levelwithout explicit feedback.