A new framework for context representation, maintenance and discovery in mobile and ad hoc networks

Liu, Q

Abstract

In this thesis, a framework has been developed for applying context
representation, discovery and sharing within mobile ad hoc networks. This
leads to the creation of a Context information Base (CiB) which is used by
each device within a mobile ad hoc network to maintain context parameters.
In addition to the CiB, a communication protocol, Context information
Communication protocol (CiComm) is also developed and integrated into the
network to enable nodes to discover and share context information.
A contextual module, containing the CiB and CiComm protocol has been
written for the NS-2 simulation tool. This enabled a detailed set of simulations
to be carried out in order to assess the operation and performance of the
overall system. The simulated results confirm the correct operation of the CiB
and CiComm protocols and show that context information can be effectively
exchanged within mobile ad-hoc networks. Furthermore, the system has
been tested under specific conditions such as information loops, device failure
and rejoining, all of which arise because of random node movement.
According to the results, the performance of the newly formed network is
related to network density, its capacity and the movement behaviour of
devices in the network. The coupling level is defined to represent the network
density; it is proved to be significant to the network since a higher coupling
level generates more context information. Network capacity decides
bandwidth of the network and how fast contextual traffic can be
communicated. Device movement is of importance when it results in nodes
leaving and rejoining the network.
The framework also shows good performance in a rapid changing
environment, compared to SLPManet, which has been used as a benchmark
comparison. The discovery success of the CiComm protocol is over 97% in
all simulation scenarios. It consumes on average 80% less bandwidth in all
scenarios, and spends 50% less time retrieving context information in most scenarios compared to SLPManet. However, the performance of the
framework is affected by the density of the ad hoc network. In a high density
ad hoc network, retrieving context information using the CiComm protocol
takes about 2.2 seconds on average, whereas SLPManet takes about 0.1
second.
Overall, the framework presented in this thesis provides a new and more
efficient method for managing context within mobile ad hoc networks.

Citation

Liu, Q. A new framework for context representation, maintenance and discovery in mobile and ad hoc networks. (Thesis). Salford : University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 3, 2012
• Award Date: Jan 1, 2009