Wireless Sensor Network (WSN) consists of very large number of sensor nodes which are deployed close to the area which is to be monitored so as to sense various environmental conditions. WSN is a data-driven network which produces large amount of data and also sensor nodes are energy-limited devices and their energy consumption is mainly associated with data routing. Therefore it is necessary to perform redundant data aggregation so as to save energy. In this work data aggregation is achieved with the help of two key approaches namely Clustering approach and In-network data aggregation. These two approaches help to save energy and thereby increasing the lifetime of the network. The proposed work has some key features like reliable cluster formation, high data aggregation rate, priority of packets, minimized overhead, multiple routes, reduced energy consumption which enhance the network lifetime. The performance evaluation of the proposed approach is carried out using Network Simulator-version 2.

In the recent years Mobile Ad-hoc Network is emerging as a very popular technology in the wireless network. Because of its dynamic topology and its infrastructure less architecture, it is vulnerable to various types of attack. Providing security against the intruder is a challenging task in MANET. In this paper, we present the Modified Enhanced Adaptive Acknowledgment (EAACK) based Intrusion Detection system that is used to mitigate the attacks. The proposed scheme is also used to overcome the limitations of watchdog. Elliptic Curve DSA (ECDSA) is used to authenticate the acknowledgement packets used in the proposed technique in order to improve the security level. When compared to the existing method, the proposed method achieves smaller end to end delay and higher throughput performance.

WiMAX femtocells are currently under the development and they are expected to play an important role in the development of indoor broadband wireless access. The presence of multiple femtocell overlapped with the WiMAX network for the purpose of improving the coverage, but the handover process in cellular network will become more complicated and may have a chance of frequent handover. This paper thus proposes the triangulation mechanism to find the exact location of MS.velocity decision handover mechanism is used to reduce neighbor cell list for successful handover. The simulation results show that our scheme improves scanning performance and also effective in terms of performance metrics, including decrease in handover delay, increase in throughputs, and bandwidth utilization. . KeywordsFemtocell, WIMAX, Handover, Quality of Service (QoS)