An Enhanced Selective Forwarding Scheme for Real-Time Applications in MANETs

In MANETs, flooding-based route discovery is usually preferred in order to set up the route with reliability between transmission pair. However, this approach may cause a serious contention in transmission between adjacent nodes and a considerable amount of control packets. In addition, most of ad hoc routing protocols establish the route with minimum hop count. Consequently, the performance of ad hoc routing protocol is considerably affected by link (or route) duration since the network comprises the nodes with unrestricted mobility and constrained range in transmission. This paper proposes a novel routing algorithm that aims to i) minimize routing overhead in route discovery procedure, and ii) guarantee a reliable and fast packet delivery between source and destination, especially in providing real-time applications over MANETs. To achieve this objective, we introduce Relay Region within the transmission range of nodes in order to select optimal next relaying nodes for supporting specific application requirements in route discovery procedure. The proposed Relay Region is defined by the limited distance progress in transmission to next relaying node in order to maintain the established route for an arbitrary length of time (i.e., route duration) while meeting packet delivery reliability and delay constraints. The simulation results showed that the proposed scheme can significantly improve the performance of packet delivery ratio and packet delivery latency, reducing transmission redundancy in route discovery procedure.