Distributed Spatial-Temporal Scheduling MAC Protocol or Underwater Sensor Networks
Date Issued
2009
Date
2009
Author(s)
Chen, Yi-An
Abstract
From ancient times, human history is associated closely with ocean. As technology progressing, people start to use sensors underwater. However, there are many characteristics of Underwater Sensor Network (UWSN) different from those of terrestrial networks. These environment limits cause new problems and new challenges.n this thesis, we focus on the design of an Underwater Sensor Network MAC scheduling protocol. In order to improve the scalability of centralized scheduling algorithm, Traffic-based One-step Trial Approach (TOTA), we propose a distributed algorithm to assign schedules.istributed Traffic-based One-step Trial Approach (DTOTA) is a receiver-driven scheduling algorithm. Schedule assignments start from sensor nodes nearest from sink, propagating in a level by level fashion. The scheduling procedure can be divided into several epochs, each with two phases: Scheduling phase and Recovery phase. Sensor nodes assign schedules for responsible edges in Scheduling phase. With the aid of Ordering mechanism, the probability of conflicted schedule results can be reduced. Whenever there is a conflict, sensor nodes can trigger the Recovery mechanism to adjust previous schedules. Eventually, the schedule assignments of all links will be conflict-free.n the part of adaptation, we use Paused Frame to transmit new schedules to all nodes within interference range. Whenever there are multiple adaptation requests happen simultaneously, in order to avoid the confusion of receiver, we use the cancellation mechanism to revoke new schedule notifications and postpone them with exponential back-off.rom simulation results, DTOTA shows a great improvement in scalability from TOTA. In network throughput, DTOTA can achieve 94% of TOTA, and 25% more than the other distributed scheduling method, Staggered TDMA Underwater Mac Protocol (STUMP). We also show that DTOTA maintains much lower adaptation overhead, even with the growing of network scale.
Subjects
Underwater Sensor Network
MAC
Distributed
Scheduling
Receiver-driven
Adaptation
Type
thesis
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