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In this thesis, the problem of mobility handling in wireless sensor network is introduced with an appreciation for the applications that may be possible once the problem is resolved.Mobility handling is solved with a simple priority backoff technique inspired by novel MAC protocols. To incorporate this technique for stationary and mobile sensor nodes, a hybrid MAC protocol called VMAC is designed with a fixed frame length. VMAC combines the advantages of scheduled-based MAC for energy savings and contention-based MAC for short transmission delays. To exploit network bandwidth, channel reuse is encouraged and is readily integrated into the protoco\. To evaluate VMAC and its performance when compared to other MAC protocols, an implementation inside NS-2 is conducted with simulations of various topologies.These topologies vary in hop-count from source to destination and also contention levels.Simulation results show that VMAC with certain frame lengths are suited for selected topologies, but the frame length of cne can always provide sufficient performance. The backoff technique is shown to be fair when nodes contend for medium access and it is even resourceful in speeding up hardware address resolution and routing. III * 1J!J~c~;JiA~~-~t-¥ ~u~ ~ :fiP.~iift* ~lH* !!~~;R*!1i~~¥IJ ~¥*~HltftHIj ~o~ #,+,#,+,+Last but not least, I would like to thank my friends for their encouragement and the great times we had together and hopefully many more great memories to come.

Recent advances in body area network technologies such as radio frequency identification and ham radio, to name a few, have introduced a huge gap between the use of current wireless sensor network technologies and specific needs of some important wireless sensor network applications such as medical care, disaster relief, or emergency preparedness and response. In these types of applications, the mobility of nodes can occur, leading to the challenge of mobility handling. In this paper, we address this challenge by prioritizing transmissions of mobile nodes over static nodes. This is achieved by using shorter contention windows in reservation slots for mobile nodes (the so-called backoff technique) combined with a novel hybrid medium access control (MAC) protocol (the so-called versatile MAC). The proposed protocol advocates channel reuse for bandwidth efficiency and management purpose. Through extensive simulations, our protocol is compared with other MAC alternatives such as time division multiple access and IEEE 802.11 with request to send/clear to send exchange, chosen as benchmarks. The performance metrics used are bandwidth utilization, fairness of medium access, and energy consumption. The superiority of versatile MAC against the studied benchmark protocols is established with respect to these metrics.

No abstract