Scaling MANETs Using Long-Range Radios and Protocol Adaptation

In this paper, we present a solution to the problem of scaling MANETs beyond 100 nodes, while providing service levels comparable to cellular networks. Flat MANETs are limited to about 100 nodes due to the high overhead of control traffic and the high inefficiency of multi-hop forwarding (Gupta-Kumar bound). Hierarchical (such as cellular) networks scale indefinitely, but do not provide uniform geographic coverage, and require pervasive infrastructure. Assuming a minimal infrastructure consisting of a fixed long-range radio, we have developed a networking system called MIANET that efficiently exploits the limited resources of this infrastructure. Specifically, MIANET drastically limits the control traffic overhead by (1) identifying "operating regimes" within the MANET that share common network and application requirements, and (2) tailoring data forwarding protocols based on the operating regime. Moreover, MIANET maximizes the benefits of fixed wireless radio by selecting to forward over this radio the data and control traffic requiring the most MANET resources (such as longest MANET paths). We have shown in emulation experiments that MIANET increases the maximum MANET size providing acceptable goodput from 100 to at least 500 nodes, compared to standard MANET forwarding using link-state routing or flooding.