Page 2 Lecture Notes in Computer Science 2865 Edited by G. Goos ...

40 L. Qin and T. Kunzsidered broken during transmission, and performance will be affected. Table 1 showsthe comparison for DSR and AODV with ideal and shadowing models for different βvalues, which correspond to different natural environments. All the simulations arerun in a 1500x300 m area with 50 mobile nodes, 20 sources, pause time 0 second,maximum speed is 20m/s. Simulation time is 500 seconds. Each scenario is run onlyonce to get an initial idea about the performance degradation. As the β value determinesaverage transmission range, comparing the results has to be done with case, wewill expound on this issue later, where we will consider node density for fair comparison.Fig. 1. Signal Power Change over a Wireless Link for (left) Shadowing Model, (right) IdealModel. They do not use the same power scale.Table 1. Performance Comparisons of DSR and AODV with Different Propagation Models.DSRAODVDeliveryRatio %ControlMessagePacketDelay (s)DeliveryRatioControlMessagePacketDelay (s)Ideal 97.69 12386 0.036 98.36 31617 0.137Modelβ=2.0 98.60 18616 0.131 92.15 25597 0.807β=2.1 82.36 50725 1.498 83.89 61062 0.988β=2.2 24.62 114533 2.541 71.08 87871 1.202β=2.3 18.81 124180 2.779 58.41 127451 1.459β=2.4 9.98 150840 2.768 43.32 126284 1.752β=2.5 4.31 204613 3.587 32.95 128958 2.053β=2.6 4.08 242623 3.623 26.55 120622 2.314Delivery Ratio: total number of received packets/total number of sent packets.Control Message: total number of control messages sent.Packet Delay: average time a packet is in transit from source to the destination.The impact of the shadowing model on the performance of DSR and AODV is a significantlydecreased packet delivery ratio (PDR), increased number of control messagesand increased packet latency. The bigger the β value, which corresponds toshorter transmission range, the lower the PDR for both protocols. Also, the averagepacket latency with a shadowing model can reach several seconds. Comparing the twoprotocols, AODV has better PDR, and packet delay does not increase as fast as DSRwith the β value. Furthermore, we observed the following: