Distributed Topology Organization and Transmission Scheduling in Wireless Ad Hoc Networks
University of Maryland College Park United States
Pagination or Media Count:
A wireless ad hoc network is a set of nodes that form an all-wireless infrastructure without the aid of any centralized administration. In this dissertation, we study two fundamental distributed resource allocation problems that arise in the ad hoc networksetting topology organization and transmission scheduling.Topology organization is studied in the first part of the dissertation. We consider ad hoc networks where multiple channels are available and defined by distinct frequency hopping sequences. Multi-channel systems can increase throughput by assigning simultaneousco-located transmissions to different communication channels. However, hosts must first synchronize their frequency hopping and transmissionreception patterns before any communication can take place. Due to this lack of initial synchronization, neighborhood discovery and network formation become non-trivial and time-consuming processes. To address these issues, we first devise a symmetric technique where two nodes use a randomized schedule to synchronize and establish a link in minimum time.This method forms the basis of a distributed topology construction protocol that starts with a set of non-synchronized nodes and quickly forms a multi-channel ad hoc network satisfying certain connectivity or throughput requirements.The second part of this dissertation introduces a novel distributed transmission scheduling framework for provision of Quality of Service QoS guarantees in wireless ad hocnetworks. Due to the multi-access nature of the wireless medium, the perceived QoSin ad hoc networks depends heavily on the underlying medium access protocol. Such a protocol must use local information and coordinate transmissions so that bandwidth is shared in a controlled fashion. Fulfilling both requirements is a well-known problem with no satisfactory solutions to date.