2008/11/21 by Mhatre, Vivek P., Rosenberg, Catherine P., Mazumdar, Ravi R.
#FOS: Computer and information sciences #Information Theory (cs.IT) #Networking and Internet Architecture (cs.NI)
paper · doi:10.48550/arxiv.0811.3585
We consider the problem of determining asymptotic bounds on the capacity of a random ad hoc network. Previous approaches assumed a link layer model in which if a transmitter-receiver pair can communicate with each other, i.e., the Signal to Interference and Noise Ratio (SINR) is above a certain threshold, then every transmitted packet is received error-free by the receiver thereby. Using this model, the per node capacity of the network was shown to be Θ(\frac1√nlogn). In reality, for any finite link SINR, there is a non-zero probability of erroneous reception of the packet. We show that in a large network, as the packet travels an asymptotically large number of hops from source to destination, the cumulative impact of packet losses over intermediate links results in a per-node throughput of only O((1)/(n)). We then propose a new scheduling scheme to counter this effect. The proposed scheme provides tight guarantees on end-to-end packet loss probability, and improves the per-node throughput to Ω(\frac1√(n) (logn)^\fracα+22(α-2)) where α>2 is the path loss exponent.