A study on performance improvement of wireless Ad hoc networks using supervisor

Abstract

Wireless ad hoc networks comprise mobile devices that use wireless transmission for communication. They can be set up anywhere and anytime. Since the wireless ad hoc networks do not need the infrastructure and the centralized administration, the installation is easy and the management cost is low so that the commercial potential is very enormous. However, the wireless channel is the scarce resource, the improvement of the throughput in the network is an important issue. However, the quality of the wireless communication depends on the communication environments such as the location of the nodes, the transmission power, the network load, and so on. Thus, the collaboration of the layers in the protocol stack is needed to improve the network throughput. To this end, the concept of the cross layer design is introduced recently. However, in the cross layer design, each layer should consider the status of the other layers and react actively. It makes difficult to construct and the manage the networks. Therefore, we propose the independent algorithms that improve the network throughput by operating alone at each layer. At the same time, the proposed algorithm can yields better performance by collaborating one another. Especially, we deal with the congestion control algorithm in the transport layer, the channel access control algorithm in the MAC layer, and the power and data rate control algorithms in the physical layer. We model the systems for the congestion control, the channel access control, the transmission power control, and the data rate control as the discrete event systems and verify the usefulness of the proposed algorithms by showing the controllability of the specification languages on the supervisory control framework. We show that the performance improvements of the proposed algorithms through some simulations.