A Study of Packet Assembly Policy in Ultra-Wideband Ad Hoc Networks

• Main Authors: Po-shen Liu, 劉柏伸
• Other Authors: Shun-Ping Chung
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/g9tv26

碩士 === 國立臺灣科技大學 === 電機工程系 === 95 === In this thesis, we study the performance of Ultra-Wideband (UWB) ad hoc networks, where multiple stations can communicate directly with each other. Since the receiver must synchronize with every transmitted data, synchronization overhead is significant in UWB networks. To reduce the synchronization overhead effectively, a transmitting station is allowed to assemble or assemble multiple packets from the upper-layer into a burst frame at MAC layer. First, we study homogeneous traffic cases. Instead of assuming that there is always a frame at each station ready to send, we consider the more realistic Poisson arrival traffic model. Furthermore, each station has a finite queue. A discrete-time Markov chain is used to characterize the system studied. In particular, each station is modeled as an M/G[Bmin,Bmax]/1/K queueing system. An analytical method is derived to calculate the performance measures of interest, e.g., throughput, average end-to-end delay, average queueing delay, average service time, and overflow probability. Since the wireless channel suffers from much higher bit error rate (BER) than its wired counterpart, so we also consider the scenarios with non-zero bit error rate. Furthermore, we also study heterogeneous traffic cases, where there are two classes of users using different packet assembly policies in order to support service differentiation. The effects of offered load, BER and packet assembly policy on the performance measures of interest for each class of users are demonstrated with our analytical results.