Reliability benefit of network coding and cooperative communication

Network coding (NC) can reduce the number of packet retransmissions and improve the network reliability in lossy networks. Reliability gain of NC over traditional error control mechanisms has been investigated in recent works. In this paper, we study reliable broadcast in a real-world topology where link loss probabilities are different from each other. We derive approximate closed-form expressions and analyse asymptotic behaviour for expected number of transmissions employing stop-and-wait automatic repeat request (ARQ) and NC as error control mechanisms. In physical layer cooperative communication, multiple nodes can transmit collectively to take advantage of spatial diversity. We incorporate the idea of physical layer cooperative communication with ARQ and NC separately, to obtain further reliability. Numerical results based on our asymptotic analysis indicate that NC offers more reliability than stop-and-wait ARQ. However, as the size of the cooperating set increases, both the schemes offer the same reliability. Approximate closed-form expressions for the reliability metric of these schemes and their asymptotic results match well with simulation results. Furthermore, simulation results establish that the proposed NC scheme outperforms existing schemes in literature.