مسیریابی فرصت طلب با کنترل پذیرش در شبکه های ad hoc بی سیم

It is challenging to provide QoS in wireless ad hoc networks, one of the main problems that affects QoS in wireless ad hoc networks is the multi-hop nature of the network. In the traditional routing, if one node at the optimal path is broken because of congestion or exhaustion of available energy, the whole path will be broken, and the source must re-route again. Opportunistic routing (OR) is an efficient approach to solve this problem, which can improve performance of system. However, it is difficult to provide better QoS in OR due to the uncertainty of forwarding paths. In the meanwhile, existing OR protocols rarely consider providing service for different types of flows, and many of them cannot make a tradeoff between opportunistic path and limited resources of nodes. Therefore, in this paper, we present a novel Opportunistic Routing scheme which considers Admission Control of nodes for the different types of flows, namely ORAC. ORAC scheme first exploits a new flow admission control scheme which is based on bandwidth, backlog traffic and residual energy of nodes to select forwarding candidates. And then, ORAC uses a novel forwarding scheme to provide services for multiple different types of flows. In this way, ORAC scheme can reduce the network congestion, and protect from any changes of traffic load for established routes. Thus, it can provide better QoS for flows. Our extensive simulation results demonstrate that the proposed scheme ORAC can achieve better network performance compared to existing OR schemes in terms of average delay, flow acceptance ratio and system throughput, routing overhead and energy consumption.