Social Networks Based Ad Hoc Mobility Models Mirco Musolesi Stephen Hailes Cecilia Mascolo University College London 3 rd UK-Ubinet Workshop Bath, 9-11 February 2005

Mobility models for ad hoc networks research Current and past research work based on simplistic mobility models Nobody moves following Random Way Point model based patterns Need for more realistic mobility models Representing real situations is difficult, but reasonable approximations of the reality are possible

Mobile ad hoc networks are social networks after all… Mobile devices are carried by humans. In a sense, it is possible to map networks of mobile nodes into a map of individuals

Social networks studies The famous “Six Degrees of Separation” Random networks studies by Erdos Small worlds model and scale-free networks Watts-Strogatz model Albert-Barabasi model Current hot topic in theoretical physics

Design of a mobility model founded on social network theory

Dynamics of the mobile hosts Problem of grouping Detection of communities Influenced by social relationships Main concept: hosts move preferentially towards the hosts that have strong relationships with them Problem of choosing goals in the simulation space

Dynamics of the mobile hosts Every host belongs to a cloud Hosts and clouds move towards a goal The movements of the hosts are the result of the composition of the their speed and the speed of the clouds they belong to. Reaching a goal: point of choice New goals chosen according to the profile of every host

Host profiling Every host is characterised by: its sociability (i.e., its tendency to stay inside a group of people) its network of social relationships Therefore, the movements of the hosts are influenced by its sociability and the attractivity exterted by the other groups of hosts

Mobility models and complex networks theory Study of the properties of the generated network: connectivity diameter average path length etc. Powerful analysis technique to help to design and improve algorithms, protocols and systems for pervasive computing

Mobility models and traces Refinement and validation of the mobility model Or viceversa, analysis and formalisation of traces by using mathematical models used to design mobility models Issues: Traces describe very specific scenarios Traces are very difficult to obtain

Current research directions Use of different social networks to represent the relative importance of the social relationships during the day Detection of community in social networks structures -> definition of community-based mobility models Geographical mapping of groups Study of the performance of algorithms and protocols with different mobility models

References Mirco Musolesi, Stephen Hailes and Cecilia Mascolo An Ad Hoc Mobility Model Founded on Social Network Theory Proceedings of the 7th ACM International Symposium on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWIM’04). Venice, Italy. October 2004.

Questions Mirco Musolesi Mobile Systems Interest Group Dept. of Computer Science, UCL