The most promising broadband wireless access technology, Worldwide interoperability for Microwave Access (WiMAX), is the commercial name of IEEE 802.16. It is popular due to its middle range access mobile, high data rates, high scalability and convenient deployment. WiMAX provides Quality of Service (QoS) to various triple-play services (voice, video and data) through five service classes. QoS provisioning to various service classes in WiMAX is achieved by a scheduler at MAC layer. Selection of appropriate scheduler is based on certain design goals, such as attainment of QoS required for variety of applications, fairness to all services, reduced complexity etc. However, in general, File Transfer Protocol (FTP) traffic starves for bandwidth under the presence of high priority real-time traffic.
This paper proposes a WiMAX hybrid scheduler that integrates homogeneous schedulers namely Weighted Fair Queuing (WFQ), strict priority and a Round Robin (RR). The unique feature of the proposed scheduler is that it has a splitter for FTP traffic with varying ratio and two stage priority schedulers for providing proper traffic load distribution for packet scheduling. The analytical modelling of proposed scheduler is achieved by Markov Chain and balance equations are solved to derive performance indicators such as mean queue length of packets, mean queuing delay, throughput and inter-class fairness for various triple-play services. The analytical results show that, as compared to recently reported hybrid WiMAX schedulers, proposed hybrid scheduler fulfils QoS requirements of various services and the splitting of FTP traffic has improved fairness among various services.

Wireless Sensor Networks (WSN) is one of the fastest rising emerging technologies that find widespread use in various applications comprising of military, health, agriculture, habitat etc. Seen as sensor network deployed at sites which can be considered as remote and hostile, the technology is seriously faced with challenges to the network and functional security at the cost of their inherent limitations in energy capacity and computing power. In this paper we have delved upon and summarized earlier research on security challenges poised to WSNs, classified the threats and then presented a generic WSN security model keeping in line with the intended security targets to be met. We have also tried to give a realistic theoretical analysis of our WSN security model against these threats.

A miniaturized multiband planar monopole Ultrawideband (UWB) antenna is presented. The penta-band antenna is comprised of a: 3.1 – 10.6 GHz UWB band, 2.4 WLAN band, 1.8 GHz GSM band, 1.3 GHz GPS and a 0.95 GHz RFID band. The proposed UWB band is realized by using half of a conventional rectangular radiator size while the other half is used to realize the other bands by employing quarter wavelength U and G shaped strips called folded CLLRs (capacitively loaded loop resonators). The designed penta-band antenna has an overall size of 25 x 30 mm2. The measured and simulated results of the fabricated prototype are compared and satisfactory results are achieved.

To design a load balanced energy efficient network has been a major concern in Wireless Sensor Networks (WSNs) since last many years. The load balancing energy-efficient clustering protocols are developed to attain the energy efficient network. But there was an issue related to the Cluster Head (CH) selection process. As the selected CH has to transmit the data to the sink node whether the node is located at a farther distance and this leads to the extra consumption of the energy by the current CH node. In order to overcome this, the novel approach is developed which is based on the multilayer architecture. The proposed method elects the CH and then a Leader node is elected from the volunteer nodes to gather the data from respective CH and then to transmit it to the base station. The simulation results depict that ILBEECP (Improved Load balanced energy Efficient Clustering protocol) outperforms the LBEECP (Load balanced energy Efficient Clustering protocol) in the terms of the dead node, alive nodes, residual energy, and energy consumption.

As most of the wireless sensor networks are unattended by humans, the energy is an important issue while deploying nodes of wireless sensor network in hazardous environments. One of the method to preserve energy consumption among sensor nodes is clustering. Using clustering, the nodes send the data to the nearest cluster head instead of far away sink. In applications using reactive wireless sensor networks, a limited number of sensor nodes are activated due to exceed in threshold values and the other nodes are under idle state. As far as the reactive wireless sensor network is concerned, the number of clusters would have been based on the number of active nodes and alive nodes.  In this work, an optimum number of clusters is computed based on the ratio between active nodes and alive nodes.  Extensive analysis and comparisons are made with existing protocol and found that the proposed methodology outperforms the existing protocol in terms of networks life time and throughput.

Vehicular Adhoc Networks (VANET) is a type of road network that provides road safety and other infotainment applications to drivers and passengers for an effective and uninterrupted communication. In this network, the communication between the vehicles are equipped with the Road Side Units (RSU). VANET is the major component of Intelligent Transportation System (ITS). Research on Vehicular Adhoc network security presents many challenging issues to the researchers. The security mechanism available for VANETs are not highly effective. Hence it is as on time requirement of new and sophisticated security solutions. This paper mainly focuses on Intrusion Detection System (IDS) for VANETs to prevent Session Hijacking Attack (SHA). The work discusses on the total number of packet generated, sent, received and dropped with varying number of nodes with the help of Network Simulator-2 (NS2) and the inferred results are discussed.