Incidence of the improvement of the transport: MAC protocols interactions on MANET performance

Abstract

A MANET (Mobile Ad hoc Network) is a collection of terminals equipped with one or several wireless network interfaces. These terminals are potentially mobile and heterogeneous. During their exchanges, every layer of the protocols stack intervenes with its functionality while ignoring its impact on those of other layers. In MANET, functionalities of the MAC (Medium Access Control) layer and the transport layer are very important. In this paper, we study the interactions between MAC protocol and transport protocols notably TCP (Transfer Control Protocol) protocol. We suggest an improvement of these interactions for a better QoS (Quality of service) in MANET. This improvement is based on two solutions. The first one consists on using MAC protocol with a new Backoff algorithm based on a dynamic adaptation of its maximal and minimal bounds in function of the number of nodes used in the network. As for the second solution, it proposes a new TCP acknowledgement mechanism in order to delay these acknowledgements according to the number of nodes. Finally, we end our paper by showing the incidence of this improvement on MANET performance.