ANALYTICAL AND SIMULATION STUDY OF TWO-STEPS BUFFER MECHANISM FOR MOBILE AD HOC NETWORKS

摘要

Buffer management scheme in multi-hop mobile ad hoc networks is mainly designed for reducing end to end delay and loss probability on one side, and increasing the data delivery on the other side. Basically, it determines which data packet is purged once a queue overflows and which data packet is served. Also, it reduces congestion that may appear in intermediate nodes as a result of limitation in resources, which make up excessive high packet loss and waste of resource utilization. In this paper, we propose two-step buffer management scheme (TSBM) suited to mobile ad hoc networks. The TSBM scheme utilizes both packet type (i.e. real-time or non-real-time) and number of hops for the arrival packets queuing and serving policy. An analytical model using a level dependent quasi-birth-death in step 1 and a two-dimensional Markov chain in step 2 is carried out. The proposed scheme is evaluated via NS2 simulator based upon small IEEE 802.11 ad hoc networks. The experimental results reveal that the proposed TSBM scheme outperforms the Drop Tail queue management scheme in terms of block packet probability, loss probability and packet delivery based on different traffic models.