In this paper we investigate network design for a wireless service provider using two orthogonal technologies: a WAN technology with uniform spatial coverage and set of LAN access points each with limited coverage. We assume that the system is designed so that users (or their agents) independently and greedily select among the two options based on maximizing a specified utility function which may be a function of the quality of the wireless link, distance to the access points, and/or congestion on system resources. We focus on two complementary aspects of this problem. On the one hand we study system performance under such decision-making strategies. We show convergence of decision-making process to an equilibrium, and that a congestion-sensitive utility can provide substantial (300%) performance improvements over natural proximity-based criterion. On the other hand, we consider various problems associated with dimensioning typically expensive backhaul links, for the WAN and set of LAN hotspots. Our results show how to best jointly exploit technologies with different coverage scales so as to statistically multiplex spatial load fluctuations in order to reduce backhaul costs.

We determine the asymptotic scaling for the per user throughput in a large hybrid ad hoc network, i.e., a network with both ad hoc nodes, which communicate with each other via shared wireless links of capacity W bits/s, and infrastructure nodes which in addition are interconnected with each other via high capacity links. Specifically, we consider a network model where ad hoc nodes are randomly spatially distributed and choose to communicate with a random destination. We identify three scaling regimes, depending on the growth of the number of infrastructure nodes, m relative to the number of ad hoc nodes n, and show the asymptotic scaling for the per user throughput as n becomes large. We show that when m /spl lsim/ /spl radic/n/logn the per user throughput is of order W//spl radic/n log n and could be realized by allowing only ad hoc communications, i.e., not deploying the infrastructure nodes at all. Whenever /spl radic/n/log n /spl lsim/ m /spl lsim/ n/log n, the order for the per user throughput is Wm/n and, thus, the total additional bandwidth provided by m infrastructure nodes is effectively shared among ad hoc nodes. Finally, whenever m /spl gsim/ n/log n, the order of the per user throughput is only W/log n, suggesting that further investments in infrastructure nodes will not lead to improvement in throughput. The results are shown through an upper bound which is independent of the routing strategy, and by constructing scenarios showing that the upper bound is asymptotically tight.