Hierarchical cooperation for arbitrary wireless networks

We consider the problem of characterizing per node throughput scaling in arbitrary extended wireless networks. Recently, Ozgur, Leveque, and Tse (2007) obtained a complete characterization of throughput scaling for random extended networks (i.e., nodes are placed in a square region uniformly at random) under a fast fading channel model. They proposed a hierarchical cooperative communication scheme to establish this result. However, their results (both the communication scheme and the proof technique) are strongly dependent on the "regularity" induced with high probability by the random node placement. As a main result of this paper, we propose a more general (and very different) hierarchical cooperative communication scheme that works for arbitrarily placed nodes (with a minimum- separation requirement). Under our scheme, we obtain exactly the same per node throughput scaling as in Ozgur et. al., showing that much less regularity is necessary for successful hierarchical cooperation. Our result holds under both fast and slow fading channel model. For small path-loss exponents alpha isin (2,3), we show that our scheme is order optimal for all node placements with minimum-separation requirement. We also show that for certain node placements, our scheme is order optimal for all alpha > 3 as well.