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Improvement of Routing Approaches in Delay-Tolerant Mobile Networks

Yadegari, Manizhe | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46701 (19)
  4. University: Sharif University of Technology
  5. Department: Computer Engineering
  6. Advisor(s): Hemmatyar, Ali mohammad Afshin
  7. Abstract:
  8. Delay Tolerant Networks are types of mobile Ad-hoc networks, in where because of the high node mobility, low node density and node diversity, there is not full connection between nodes in the whole network; therefore, the probability of existence of end-to-end path between source and destination is low. Due to these properties, message routing in delay tolerant networks has turned to be a challenge, this type of networks work based on the concept of store, carry, forward; for instance, a node may store a message in the buffer for a long time and carry it along until meeting an appropriate contact opportunity. Delay tolerant networks are capable of providing communication services in environments where there is no guarantee that the end-to-end path between source and destination exists, while traditional routing algorithms are not applicable in such networks. So far many methods have been proposed for routing in these networks, which, in this thesis, are explained and classified in two groups of conscious and blind.
    In the thesis, after a review and evaluation of previous algorithms, our proposed method, which is a conscious one, is offered. Simulation results show that using conscious algorithms, in addition to improving network performance parameters, such as delivery rate and end-to-end delay, make optimal use of their resources. The objective of this thesis is presentation of an algorithm, called HP-A, which is a powerful and effective algorithm, has an acceptable performance and is easy to implement. In delay tolerant networks, selection of relay nodes to carry the messages and forward them to the destination plays an important role in the performance of the routing algorithm. The proposed algorithm uses the contact information of nodes, consciously choose the relay nodes, and forward the message from the source to the destination at the earliest appropriate opportunity. Simulation results indicate that this conscious selection increases the delivery rate of messages, moreover, reduces delay and the overhead of the algorithm, resulting more optimal resource consumption.
    Results comparing the proposed algorithm with Prophet, epidemic and AAR algorithms in ONE simulator show that the proposed algorithm has better performance in parameters such as rate of delivery, delivery delays and the overhead of the algorithm resulting in improved resource consumption
  9. Keywords:
  10. Routing ; Internetworking ; Delay Tolerant Networks (DTN) ; Contact Problem ; Delivery Predictability

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