On the Design of a Dual-band Unequal Power Divider Useful for Mobile Communications

A new method of designing a dual-band unequal power divider is presented. The method considers realistic conditions, since it assumes lossy transmission lines and unmatched terminal loads. A suitable optimization procedure is applied using genetic algorithms in order to satisfy several requirements at both frequencies. The method is suitable for a wide range of applications and responds with success at the mobile communication frequencies of 900 and 1,800 MHz.     

Exploiting Selfishness,Altruism and Common Welfare to Enhance Performance of Routing Protocols for Mobile Ad hoc Networks

Mobile Ad hoc Networks are sensitive to selfish behavior that may occur due to restricted power or other resources. Several approaches have been investigated so far to address this problem. In many of them, upon detection, a selfish node is punished with isolation from network services access and in most cases with no possibility for redemption. In this paper, we show that selfish behavior can be exploited to improve network performance. We modify an existing routing protocol by introducing an altruism coefficient to model the overall satisfaction of every node from the network services. When the altruism coefficient is increased, the selfish behavior is decreased. We extend our approach by introducing a common welfare factor, which actually enforces the nodes to cooperate when the network connectivity is critical. A network simulator is utilized to show the impact of our schemes on the performance of the routing protocol when selfish nodes are present in the network.