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1. O. Apilo, Performance of randomized forwarding in large ad hoc networks, Helsinki University of Technology, 2006, Master's Thesis (bib)

   Abstract: An ad hoc network is a wireless network consisting of mobile nodes that communicate with each other in a multihop fashion without any need for fixed infrastructure or centralized control. Most of the factors that affect the performance of an ad hoc network are related to routing and medium access control (MAC). In this study, different routing and MAC methods for ad hoc networks are surveyed and a more detailed study is made on the performance of different forwarding methods in a large ad hoc network. In this latter part of the study, we model a large ad hoc network. In this setting, the routing problem can be decoupled into a macroscopic and a microscopic level. At the microscopic level, the direction of packet flow is given by the macroscopic level routing algorithm. Thus, the task of the microscopic level forwarding method is to maximize the flow of packets in the given direction. The packet flow intensity depends only on the slotted ALOHA parameter for the transmission probability and the network density. We study the maximum packet flow intensity by simulations with respect to these two parameters and compare the performance of four different forwarding methods, namely one deterministic and three randomized forwarding methods. The randomized forwarding methods achieved better performance than deterministic forwarding. Deterministic forwarding concentrated traffic on a few paths leaving most of the network under-utilized, while randomized forwarding spread traffic to the network more efficiently. Of the randomized methods, opportunistic forwarding, which modifies the MAC protocol to co-operate with forwarding rules, was clearly the best.