Shenjin Sun

Graduation Semester and Year




Document Type


Degree Name

Master of Science in Computer Science


Computer Science and Engineering

First Advisor

Yonghe Liu


The WiMedia MAC for UWB based WPANs is currently preferred among standards for wireless network since it requires non-infrastructure for ad hoc network, and also supports for Quality of Service (QoS). Without infrastructure, coordination of devices within radio range is achieved by the exchange of beacon frames, which is an overhead in WiMedia MAC, since no data transmission is allowed during Beacon Period (BP). In a dynamic network, devices might leave or join in, so beacon slots will be released or reoccupied with the changing of network. And BP contraction mechanism is aimed at reusing the released beacon slots in a dynamic network by shifting the latest movable beacon slot to the earliest empty beacon slot, so that more time slots will be saved for data transmission. In this thesis we investigate the performance of BP Contraction Mechanism in WiMedia MAC by modeling it as distance-2 coloring problem, and On-Line First-Fit algorithm is applied to solve the problem. We carry out different scenarios of simulation for dynamic ad hoc networks to study the stability of BP contraction mechanism, and also the maximum propagation times of BP contraction. The simulation results demonstrate that BP contraction mechanism has a stable performance in dynamic networks, and the nodes' joining/leaving order has small influence on the behave of BP contraction. The propagation of BP contraction can be terminated in a few times, which shows the network will become stable very soon after devices joining or leaving.


Computer Sciences | Physical Sciences and Mathematics


Degree granted by The University of Texas at Arlington