Performance analysis of QoS routing protocol for WiMedia networks

Though the WiMedia supports higher data rates than other WPAN technologies, a WiMedia device cannot reach other devices that are separated from it by more than 10 m, which is the typical limited transmission range of the WiMedia protocol. In this work, we propose a multi-hop QoS routing protocol to enable WiMedia devices to transmit real-time data to devices that are located out of the transmission range. The proposed routing protocol is a hybrid algorithm, which mixes the table-driven and on-demand routing algorithms, searching one or more routes according to the number of hops to a destination device. WiMedia MAC is potentially capable of learning the existence of neighbor devices by using a beacon frame. By utilizing the neighbors' information, all devices can create routing entries for devices within 2-hops periodically. For devices beyond the 2-hop range, the newly designed on-demand routing algorithm is applied to multi-hop routing. If a routing entry for a destination device is not listed in the routing table, the source device sends a request packet to 2-hop range devices which could be found in the routing table. Since every device maintains routing entries for 2-hop range devices in the routing table, the request packet is replied in advance before its arrival at the destination device. Also, to decide the optimal route for a destination device, the number of medium access slots (MASs), received signal strength indicator (RSSI) and hop count are utilized to establish a QoS-enabled routing table. We perform ns-2 simulation to investigate the performance of the proposed routing protocol with AODV and DSDV. The simulation results show that the proposed protocol has better throughput and lower overhead than other protocols.