A Comparison of Opportunistic and Deterministic Forwarding in Mobile Multihop Wireless Networks

While opportunistic packet forwarding has been extensively studied in the case of single hop communication, only recently has opportunistic forwarding for multihop networks been explored. One key aspect of opportunistic forwarding is that the node that forwards a packet is determined on-the-fly and depends on which nodes receive the packet. On the other hand, in deterministic forwarding, the node that will forward the packet is predetermined. There are several key differences between these approaches. Opportunistic forwarding is able to make use of links where packet delivery is possible with a low probability and can easily accommodate channel fluctuations. But in order to reduce collisions, overhead is required to determine which node will forward the packet. The deterministic scheme considered is able to adaptively react to changes in the route quality, but requires overhead to update the route. In this paper, we examine which approach provides the best performance. It is found that the relative performance depends on mobility and the physical layer. However, in most cases, deterministic forwarding, along with route quality monitoring and high frequency route updates, outperforms opportunistic forwarding.