Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
In this thesis, a mobile communication system based on a sparse infrastructure is addressed. The cost of a wireless infrastructure has been shown to be proportional to the service area covered and to the data-rate provided to the users. Therefore, if an operator wants to increase the data-rate per users while maintaining a low cost, the number of Access Points deployed has to be reduced.
The Infostations concept which was already used to provide high data-rate to small disjoint areas, is used and extended with Multihop Capable Nodes. These nodes have additional memory capacity dedicated to `store-and-forward' the messages until their delivery.
Considering a non delay sensitive service but requiring high data-rates (a delay tolerant multimedia game), the investigation is conducted in both a linear and a sparse-hexagonal environments with simple models of tra±c and mobility. The linear environment can be compared to a street or highway where the nodes have a constrained mobility whereas the sparse-hexagonal is a partially covered hexagonal environment which resembles a cellular network, but with lower APs density than what required for providing complete coverage. The goal of the thesis is to determine how low the coverage can be but still provide interesting performances.
The system performances are evaluated through the delivery rate of the messages, the relative delay to deliver a message, the memory occupation and the number of hops performed by a message to be delivered.
The simulation results show that the system can provide good performances for delivery rate and relative delay in some scenarios, but at the expense of higher memory occupation. The system uses differently the multihopping and the mobility of the nodes to combat the lack of coverage depending on the environment and the user density.
2005. , 52 p.