A novel priority based scheduling scheme for ad hoc networks

Since ad hoc networks provide users convenient access to information anytime anywhere, they have many applications. However, scheduling packet based on assigned priority is challenging. This paper presents design and analysis of a priority request to send (RTS) packet scheduling (PRPS), a distributed MAC protocol which can ensure priority based packet scheduling for multiple traffic flows when different priority classes of traffic are present. For PRPS, nodes send their requests in a contention period and send data packets in a contention-free period and a state transition mechanism supports a change between contention and contention-free phases. An analytical model is introduced to determine the system performance when the traffic is in saturated region. The results of PRPS are compared with that of the IEEE 802.11 standard. Extensive simulations indicate that the system performances such as throughput and the average delay etc, are improved with respect to the IEEE 802.11 distributed coordination function (DCF).