| Summary: | Due to the rapid growth of wireless technology, there has been a growing
interest in the capabilities of ad hoc networks connecting mobile phones, PDAs and
laptop computers. The distributed and self-configurable capabilities of ad hoc
networks make them very attractive for some applications such as tactical
communication for military, search and rescue mission, disaster recovery,
conferences, lectures, etc.
In this thesis, we describe several new time scheduling algorithms for multihop
packet radio networks; MaxThrou, MinDelay, ECTS (Energy Conserving
Transmission Scheduling) and LA-TSMA (Location-Aided Time-Spread Multiple-Access). The MaxThrou and MinDelay algorithms focus on maximizing the system throughput and minimizing the delay bound by using constant weight codes. In these algorithms, each mobile host is assigned a word from an appropriate constant
weight code of length n, distance d and weight w. The host can send a message at
the j[superscript th] slot provided the assigned code has a 1 in this j[superscript th] bit. The MaxThrou and
MinDelay scheduling algorithms are better than the previously known algorithms in
terms of the minimum throughput per node and/or the delay bound.
Since most of mobile hosts are operated using the scarce battery, and the battery
life is not expected to increase significantly in the near future, energy efficiency is a
critical issue in ad hoc networks. The ECTS algorithm conserves the power using
strategies that allow the network interface to use the low power sleep mode instead
of the idle mode, and also eliminates data collisions by introducing Request-To-Send (RTS) and Clear-To-Send (CTS) control slots. Simulation study shows that
the ECTS algorithm outperforms previously known protocols.
Due to the increasing popularity of mobile networking systems, the scalability
becomes a significant new challenge for ad hoc network protocols. To provide a
scalable solution for mobile ad hoc networks, we introduce the LA-TSMA
algorithm. Instead of assigning a globally unique TSV to each host as done in
previous topology-transparent scheduling algorithms, the proposed algorithm
assigns a locally unique TSV to each host. In LA-TSMA, a territory is divided into
zones, and the mobile hosts located in different zones can be assigned the same
TSV. === Graduation date: 2003
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