To enable the appearance of self-organised information and communication systems, mobile devices form networks in an ad hoc fashion and must cooperate to provide the functionality required for networking in the absence of a fixed infrastructure.
The research objective of the project is to produce a rudimentary protocol for ad hoc networks of the future, falling outside the capacity of current protocol designs and produced via emergence. Such a design needs to meet a number of global criteria that offer solutions to communication scenarios involving local occurrences, which cannot be premeditated prior to deployment. This process involves the creation of an “alphabet” from the characteristics of existing protocol implementations. Expanding on this, not only must the alphabet be established but also ways and techniques for combining the letters in it, so that meaningful words emerge.
The background to be assimilated falls into two categories, namely ad hoc networking and emergence. In contrast to cellular systems and wireless local area networks, ad hoc wireless networks perform peer-to-peer communication, i.e. directly between the nodes without a “base station”. They can have infrastructure or a pre-established node hierarchy but these may potentially be dynamic in response to a changing environment. Such systems may be termed infrastructure-less wireless networks or, more recently, mobile ad hoc networks (MANETs). The mobility of the network nodes is a crucial defining characteristic of ad hoc wireless networks, determining the time over which measurements regarding channel and interference conditions remain in effect. Emergence describes a set of structures carrying properties that can be observed within the system, and from the interaction of these properties, the same structures change in time, obtaining a number of second order properties 1 . A new property in the resulting structures is emergent if and only if it cannot be observed in the original set of structures. Despite the behaviour of the entities involved being managed by a set of very simple rules, the system as a whole has the ability to solve quite complex problems. This process may be observed in natural systems such as ant colonies 2 , and has been has been applied successfully to artificial systems, such as the optimisation of the performance of a helical antenna 3 .
This project is interesting because there are no protocol solutions at present that can do what is required.
Current wireless protocols 4 focus on techniques for establishing routes and exchanging information in a dynamic environment. Routes in the network use multiple hops (multihop routing) via intermediate nodes to provide connections. This method offers significant increases in the capacity of ad hoc wireless networks but realising these via a decentralized routing strategy has remained elusive.
The techniques required will primarily be analysis and simulation. The simulation work can be undertaken in a number of computer languages such as, for example, C++ or Java. There are also freely available simple simulation tools, such as StarLogo, and the supervisor will be able to provide modest extra funds if an ideal modelling tool is identified during the work. The student will have access to work by a previous Engineering student, who produced
MANET protocols to withstand attacks by computer hackers 5 .
The prospective deliverables of the project will be (a) an alphabet for wireless routing protocols that maps protocol elements to an appropriate representation; (b) an elementary protocol produced via emergence using the symbols of the alphabet identified.
This work will benefit a wide range of users , including those who wish to employ ad hoc networks for search and rescue tasks, for hazardous industrial processes and for security reasons. The machines of science fiction routinely display behaviour that is some way ahead of what we can achieve today. For example, it is not currently possible for a group of autonomous robots to discover a route into a burning building, organise themselves and undertake a rescue mission. To do this, whichever robot discovers an entry must become the head of a group of robots and, although this resembles clustered implementations of software protocols that exist, there is no guarantee that such current protocols are fit for the purpose of handling the other communication tasks needed in the network.
This project has good prospects for leading into a PhD project , and a PhD follow-on would (a) further develop the simulation to consider realistic scenarios; (b) propose and evaluate methods to compare the emergent protocols; (c) incorporate other factors (such as error correction coding or compression) into the work to ascertain their impact.
1
N. Baas, “Emergence, Hierarchies and Hyperstructures” Artificial Life III, MIT Press, 1992, pp. 515-537.
2 D. M. Gordon, “Ants at Work: how an insect society is organized”, Free Press, Simon & Schuster, 2000.
3 J.D. Lohn, W.F. Kraus, D.S. Linden, “Evolutionary Optimization of a Quadrifilar Helical Antenna”, IEEE AP-S Int. Symp.
3 , 2002, pp. 814-817.
4 E. M. Royer, C-K. Toh, “A Review of Current Routing Protocols for Ad-Hoc Mobile Wireless Networks”, IEEE Pers. Comms., 6 , 1999, pp. 46-
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5
I. Pavlosoglou, “Emergence in the Security of Protocols for Mobile Ad Hoc Networks”, PhD thesis, University of Warwick, July 2005.
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