Throughput and delay scaling laws for mobile overlaid wireless networks

In this paper, we study the throughput and delay scaling laws over two coexisting mobile networks. The primary network consists of n   randomly distributed primary nodes which can operate as if the secondary network is absent. However, the secondary network with a higher density m=nβm=nβ, β>1β>1 is required to adjust its protocol. By considering that both the primary and the secondary networks move according to random walk mobility model, we propose a multi-hop transmission scheme, and show that the secondary network can achieve the same throughput and delay tradeoff scaling law as in stand-alone network Ds(m)=Θ(mλs(m))Ds(m)=Θ(mλs(m)). Furthermore, for primary network, it is shown that the tradeoff scaling law is given by Dp(n)=Θ(nlognλp(n)), when the primary node is chosen as relay node. If the relay node is a secondary node, the scaling law is Dp(n)=Θ(nβlognλp(n)). The novelties of this paper lie in: (i) detailed study of the delay scaling law for the primary network in the complex scenario where both the primary and the secondary networks are mobile; (ii) the impact of buffer delay on the two networks due to the presence of preservation region. We explicitly analyze the buffer delay and obtain an expression as DSRII(m)=Θ(1/nβ−1as(m)).