A Study On The Distributed Address Assignment Algorithms For Zigbee Networks

ZigBee network is a kind of low overhead,low rate,low cost WSNs, it becomes thehot point of research for the above features, but the distributed address assignmentmechanism (DAAM) that is default mechanism of ZigBee network has the orphanproblem (partly nodes can't receive the address),the topology optimation problem and soon. The exited improved algorithms can remit the orphan problem, but they destroy thetopology structure, increase the communication overhead and the time of addressassignment, such as the borrowed address algorithm,reorganised address algorithm andso on. In this paper, firstly a survey of ZigBee networks is presented, and the exitedaddress assignment algorithms are analysed, and compared based on their differentprinciples, and then the paper proposes the following three improved algorithms for theshortcomings of DAAM and the exited algorithms.The first improved algorithm is the Distributed Borrowed Address AssignmentAlgorithm based on2-hops neighbors (DBAA-2) for the topology optimation problem ofDAAM.It assigns the free addresses from2-hops neighbors to the nodes for theoptimization of the network topology to increase the success rate of joined nodes.Meanwhile, the present tree routing protocol was improved to suit the borrowed addresses.The algorithm is simulated and compared with the Distributed Address AssignmentAlgorithm (DAAM) and another improved algorithms-SLAR (Single Level AddressReorganization) based on OPNET platform. Both theoretical analysis and simulationresults show that DBAA-2outperforms others in the performance of success rate ofaddress assignment, communication overhead, time spent to assign an address and so on.The second improved algorithm is Address Assignment Algorithm based onTopology Maintenance (A2BTM) for the problem of maintaince topology. It borrowsaddresses firstly from the descent nodes in the same branch for orphan router nodes tomaintain the network topology, adds the mechanism of immediate reply for borrowedmessage, and assigns the remainder addresses unused by DAAM for the orphan enddevices to control the overhead and time spend on founding net. Meanwhile, the presenttree routing protocol was improved to suit the borrowed addresses. The A2BTM algorithmis simulated and compared with DAAM,HAC(Hybrid Address Configuration) and SLARbased on OPNET platform. Both theoretical analysis and simulation results show that A2BTM outperforms others in the performance of success rate of address assignment,communication overhead, time spent to assign an address, data packets hop and so on.The third improved algorithm is a segmentation-based on-demand scalable addressassignment algorithm (SOSAA) for the orphan problem. It segments the16bit addressspace according to a value predefined by DAAM, parent nodes extends its address spaceto a new segment based on own load conditions on-demand, to increase the success rateof address assignment. Meanwhile, the present tree routing protocol was improved to suitthe extended addresses. The SOSAA algorithm is simulated and compared with DAAM,HAC and SLAR based on OPNET platform. Both theoretical analysis and simulationresults show that SOSAA outperforms others in the performance of success rate ofaddress assignment, communication overhead, time spent to assign an address, datapackets hop and so on.Finally this paper proposes the research directions of opportunistic networks in thefuture, and gives the conclusion.