A cooperative rotational sweep scheme to bypass network holes inwireless geographic routing

Geographic routing in wireless ad hoc networks is characterized by routing decisions made from locally available position information, which entails network scalability. However, it requires an effective recovery approach to sending a packet bypassing network holes whenever the simple greedy forwarding fails. Among well-known approaches, rotational sweep routing algorithms based on a circular arc are able to achieve packet delivery guarantee as well as low routing path stretch under the impractical assumption that a wireless link exists between two nodes if and only if their distance is less than one unit. Instead, we propose a cooperative rotational sweep algorithm taking into account practically imperfect wireless connections. The algorithm involves a regular rotational sweep procedure and a cooperative one both making use of iterative sweeps with circular arcs of decreasing size subjective to a minimum size constraint. Essentially, the cooperative rotational sweep procedure resolves hidden node issues through exploiting packet header overheads for memory of the latest routing path while iterative sweeps reduce the possibility of missing pivotal relays. Simulation results demonstrate that the proposed scheme presents the benefit of using packet header overheads to support high end-to-end routing success probabilities without sacrificing the inherent feature of localized routing.