Capacity of Hybrid Networks

The rate at which information can be exchanged between nodes in a hybrid network is investigated. The network includes n ad hoc nodes and b base stations, where the ad hoc nodes can share information through the wired infrastructure in addition to wireless ad hoc communication. The per-node throughput scaling achievable in this hybrid network as n (and b) grows was studied in previous work for both one-dimensional and two-dimensional networks. This work completes this previous work in three ways. First, the wired network is modeled more realistically where the base stations are only connected to their nearest neighbors with finite bandwidth links as opposed to a fully connected network with infinite bandwidth. Second, through cutset methods, we show upper bounds on the throughput which matches the lower bounds for a wide range of values of b. Finally, by establishing a new result on the maximum of a sequence of Poisson random variables (which is of independent interest), we improve previous lower bounds in the extreme case where the number of base stations scale almost on the same order with the number of ad hoc nodes, and also show a matching upper bound in that case for one-dimensional networks.