Quality of service aware routing protocols for mobile ad hoc networks

The Ad hoc network is set up with multiple wireless devices without any infrastructure. Its employment is favored in many environments. Thus, many efforts are put on ad hoc networks at both the MAC and routing layers. Meanwhile, QoS aware issues are considered in both MAC and routing layers for ad hoc networks. This thesis work gives a review of ad hoc networks at both the MAC and routing layers. IEEE 802.11 is discussed and routing protocols widely used in ad hoc networks are analyzed and compared. Solutions for QoS aware routing protocols are summarized. Evaluations are presented by doing simulations with both the QAODV and AODV routing protocols. During simulations with NS2, different data rates and node moving speeds are tested in order to see the performance of the QAODV compared with the AODV. The results show that the QAODV outperforms the AODV in terms of end to end delay when traffic on the network is high at the expense of transmitting more routing packets. When the network begins to be saturated, the route discovery and maintenance processes become more important. Not all routes from source to the destination chosen by the AODV routing protocol are suitable for real time traffic transmissions, since there is no QoS considered in the routing protocol, whereas the QAODV which considers QoS shows extremely good results. In addition, prohibiting packets sending from sources to the network when there is no suitable route also helps to prevent wasting the data rate on the network. Thus, from the simulation results and analysis, it can be seen that adding QoS to routing protocols is meaningful to optimize the performance of traffic on the network especially the real time traffic