Data Dissemination in Wireless Broadcast Channels: Network Coding or Cooperation

Abstract

Network coding and cooperative diversity have each extensively been explored in the literature as a means to substantially improve the performance of wireless networks. Yet, little work has been conducted to compare their performance under a common framework. Our goal in this paper is to fill in this gap. Specifically, we consider a single-hop wireless network consisting of a base station and N receivers. We perform an asymptotic analysis, as N rarr infin, of the expected delay associated with the broadcasting of a file consisting of K packets. We show that if K is fixed, cooperation outperforms network coding, in the sense that the expected delay is proportional to K (and thus within a constant factor of the optimal delay) in the former case while it grows logarithmically with N in the latter case. On the other hand, if K grows with N at a rate at least as fast as (log N)r, for r > 1, then we show that the average delay of network coding is within a factor less than two of the optimal delay, no worse than the average delay of cooperation. Our analytical findings are validated through extensive numerical simulations.