A "Small World" Approach to Heterogeneous Networks

Sanjeev R. Kulkarni, Alex Reznik, Sergio Verdu
2003 Communications in Information and Systems  
We consider a heterogeneous (also called "hybrid") ad-hoc network with wired and wireless links. This type of network was previously considered by Kulkarni and Viswanath in [9] where achievable transport capacity growth rates were demonstrated for a structured wired infrastructure. The present paper improves on this work by demonstrating that efficiency can be increased significantly if the wired links are introduced at random. Introduction. In this paper we consider the effect of adding a
more » ... infrastructure to an unstructured (ad-hoc) wireless network. The impact of such a modification on the original wireless network can be tremendous. Unlike the wireless channel, which suffers both from interference issues as well as from path loss over large distances, the wired infrastructure can provide low-cost transport of a significant amount of data over large distances without interference with other simultaneous communications. However, the existence of such an infrastructure often carries a significant cost in and of itself. Thus, in particular, one would like to use as little wired infrastructure as necessary. A systematic study of scaling laws in ad-hoc wireless networks has been initiated in the work of Gupta, Kumar and Xie [6],[21] and [5] . In particular, Xie and Kumar showed that for a large range of path loss models the transport capacity (the distance -bandwidth product) of a purely wireless network scales no better than Θ( √ n) when the network size is fixed. Furthermore, Gupta and Kumar demonstrated how such scaling laws are achievable for all path loss models using an interference-avoiding communications protocol. The recent work by Kulkarni and Viswanath [10] gives a simple deterministic protocol that achieves the scaling laws of Gupta and Kumar [6] eliminating much of the complexity of the original routing protocol. The protocol in [10] is based on the related problem of packet routing on a square grid of parallel processors [7], [11] . The protocol is straightforward and deterministic and thus provides a natural starting point to include a wired infrastructure into the ad-hoc wireless network. The reference *
doi:10.4310/cis.2003.v3.n4.a6 fatcat:4mq54lazlfantdw4xjadqpdpci