Optimal energy consumption for dynamic network coding in cooperative multicast system

Reducing energy consumption has drawn much attention in wireless multicast services. As one of the most substantial breakthroughs in communication fields, network coding, recombining the inputs into one combined output, enhances the efficiency of the wireless network significantly. Furthermore, the two-stage cooperative multicast scheme has been proved to be an efficient approach to combating the channel fading of each end user in a multicast group. In this paper, we apply dynamic network coding (DNC) and two-stage cooperation in a network composed of a single base station and multiple end users, focusing on energy consumption per bit as the performance criterion. Three transmission schemes are used in the network: minimum-SNR energy saving scheme (ESS), ESS-XOR and ESS-DNC. Compared to ESS and ESS-XOR, the proposed ESS-DNC applies dynamic network coding at the selected relays in the 2^nd stage, less energy being consumed because of more transmission time being saved. It is shown by simulation results that the proposed scheme can always achieve better energy efficiency in terms of energy consumption per bit.