Title page for ETD etd-05082005-223850


Type of Document Dissertation
Author August, Nathaniel John
Author's Email Address nate_august@yahoo.com
URN etd-05082005-223850
Title Medium Access Control in Impulse-Based Ultra Wideband Ad Hoc and Sensor Networks
Degree PhD
Department Electrical and Computer Engineering
Advisory Committee
Advisor Name Title
Ha, Dong Sam Committee Chair
Armstrong, James R. Committee Member
Lockhart, Thurmon E. Committee Member
Reed, Jeffrey Hugh Committee Member
Tront, Joseph G. Committee Member
Keywords
  • ultra wideband
  • carrier sense
  • medium access control
  • busy signal
  • ad hoc networks
  • multi-channel
  • sensor networks
Date of Defense 2005-05-05
Availability unrestricted
Abstract
This thesis investigates distributed medium access control (MAC) protocols custom tailored to both impulse-based ultra wideband (I-UWB) radios and to large ad hoc and sensor networks. I-UWB is an attractive radio technology for large ad hoc and sensor networks due to its robustness to multipath fading effects, sub-centimeter ranging ability, and low-cost, low-power hardware. Current medium access control (MAC) protocols for I-UWB target small wireless personal area networks (WPANs) and cellular networks, but they are not suitable for large, multihop ad hoc and sensor networks. Therefore, this paper proposes a new type of MAC protocol that enables ad hoc and sensor networks to realize the benefits of I-UWB radios. First, we propose a method to overcome the challenges of quickly, reliably, and efficiently sensing medium activity in an ultra wideband network. This provides a base MAC protocol similar to carrier sense multiple access (CSMA) in narrowband systems. Next, we propose to exploit the unique signaling of I-UWB to improve performance over the base MAC protocol without the associated overhead of similar improvements in narrowband systems. I-UWB enables a distributed multichannel MAC protocol, which improves throughput. I-UWB also facilitates a busy signal MAC protocol, which reduces wasted energy from corrupt packets. Finally, because the I-UWB Physical Layer and MAC Layer affect the network and application layers, we propose a cross-layer adaptive system that optimizes performance. Physical Layer simulations show that both the base protocol and the improvements are practical for an I-UWB radio. Networks level simulations characterize the performance of the proposed MAC protocols and compare them to existing MAC protocols.
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