Protocol design in wireless networks: featuring channel access and vehicular communications

Loading...
Thumbnail Image
Date
2012
Journal Title
Journal ISSN
Volume Title
Publisher
University of Alabama Libraries
Abstract

Wireless Networks provide a very cost efficient solution for data connectivity over wide areas enabling ubiquitous computing environment through multi-hop relay. The scope of this dissertation encompasses two correlated domains of Wireless Network area, one is the Multi-Radio Multi-Channel Wireless Mesh Network (MRMC-WMN) and the other is Vehicular Ad hoc Network (VANET). The research issues studied here are related to IEEE 802.11 based, multi-hop ad hoc wireless network. In the first part, we deal with some of the fundamental issues of Wireless Networks, with particular emphasis given on approaches and techniques for channel assignment and delay analysis in multi-radio multi-channel wireless mesh network. A novel channel assignment scheme has been proposed utilizing Partially Overlapped Channel (POC).We also introduced the notion of I-Matrix as a new interference model which takes into account one additional type of channel interference ignored by most researchers. Specifically, our interference model considers the effect of Self-Interference for multi-radio environment in addition to Adjacent Channel Interference(ACI) and Co-Channel Interference. We evaluate the performance of our POC based channel assignment algorithm in terms of capacity by comparing with the one using only orthogonal channels. Our results show capacity improvement as the increased link assignments at an average of more than 15 percent. The second part presents a spatio-temporal analysis of multi-hop V2V connectivity and network partitioning along with the statistical behavior of urban taxi mobility pattern. We developed two new approaches in analyzing the connectivity. One is the bitwise matrix manipulation for determining multi-hop connectivity and transitive closure. The other is the detection of saturated connectivity based on the k-hop reachability. The proposed algorithm of generating multi-hop reachability and network partition, though not optimal in performance, is better than traditional BFS approach in terms of space and time complexity. We then apply our algorithm for spatio-temporal analysis of urban taxi mobility pattern. Using the presented empirical analyses, wireless researchers can estimate the capabilities and constraints of vehicular communication from connectivity and mobility patterns as well as government can plan and work on issues related to implementing proper DSRC infrastructure for optimal data connectivity in urban area. We also propose an innovative application of V2X communication for Intelligent Transportation System (ITS). The application relates to DSRC based taxi hailing system in urban metropolitan area. The proposed system can work in both presence and absence of ITS infrastructure. Our evaluation results show that the system can not only reduce the passenger's waiting time and driver's empty cruise time, but also increase the overall taxi availability using multi-hop communication.

Description
Electronic Thesis or Dissertation
Keywords
Computer science, Electrical engineering, Transportation planning
Citation