The limited battery usage of a sensor node is one of the significant issues in WSNs. Therefore, extending the lifetime of WSNs through energy efficient mechanisms has become a challenging research area. Previous studies have shown that clustering can decrease the transmission distance of the sensor nodes thus, prolongs the lifetime of the network. In literature, most of the LEACH variants aim to set-up clusters in each round by changing CHs randomly. These formations cause to spend high amount of energy and induce additional network costs. In this paper, an energy-efficient nearest constant clustering approach is proposed to solve the problems of LEACH based protocols. The proposed approach uses constant clusters which are formed only once when algorithm starts. The cluster formation remains fixed until the energies of the all sensors are finished. Proposed approach aims to select nearest CHs in each cluster randomly without changing the cluster formations.

This paper presents the experimental results of a study on radio frequency attenuation path loss conducted in Ekiti State, Nigeria. The objective of the study is to develop a path loss model comparable to the existing path loss models through a real time application of outdoor VHF signal propagation measurements of the Nigeria Television Authority (NTA) Channel 5 and carrier frequency of 175.25 MHz located in Ado-Ekiti, Ekiti State, Nigeria. Experimental measurements were taken in three routes covering the entire state. Analysis of the data collected from the experiments resulted in models which are in agreement with the existing standard models. Root Mean Square Errors were calculated for all the path loss models. Results show that the signal of the station was generally poor along the routes considered as the deviations of the measured path losses from the free space path loss exceed 6 dB in most cases.

Nowadays, Li-Fi is becoming very popular and catching the interest of a number of users with its advanced technology-based features. It brings a new resolution in the wireless communication and people are showing so much curiosity to know about it. Li-Fi is an optical wireless communication-based technology which transmits data over the network through a light source like LED’s instead of radio frequency signals (RF) with very high data rate. The aim of this paper is to give full- fledged knowledge about Li-Fi & its applications. This paper also attempts to clarify the basic difference between wireless technologies and their evolution & how this new technology is leading all over the world with its features like less power consumption, less requirement of maintenance, & bi-directional in nature. Li-Fi eliminates the effect of harmful radiations that occur due radio signals as in Wi-Fi and has less latency rate. This paper gives an overview and the general idea about working on Li-Fi technology and how it will help in the development of bright future as it is beyond the expectations of end users.

Vehicular Ad hoc Network could manage the various critical issues of road transport. That is why it is the most crucial field of research for most of the researchers. This survey paper discusses various issues related to Security Challenges, Security Architecture actors, Security Authentication, Application Constraints, various trust models etc. this paper encourages you to think about various fields of work need to be carried out in this field for the better VANET environment. Various schemes have been mentioned which could be improved further as per considering various real time conditions.

Emergence of wireless embedded applications is resulting in the communication among sensor nodes connected in a wireless personal area network. Sensor nodes gather the real time information and transmit it to the desired application. This requires transmission of IPv6 packets over Low-power wireless personal area network and is called 6LoWPAN. IPv6 is resource intensive protocol whereas 6LoWPAN is resource constraint due to small packet size, limited device memory, short transmission range, and less data rate of sensor nodes. Also these nodes in 6LoWPAN are mainly battery operated hence minimum power consumption is also a major constraint.
To make the efficient transmission of information in such a resource constraint network, an adaptation layer was suggested and implemented by Internet Engineering Task Force (IETF). The placing of this additional layer is in between network layer and data link layer of TCP/IP protocol stack. This paper contributes in the detailed analysis of need of adaptation layer in 6LoWPAN protocol stack. The necessity of this additional layer is justified by explaining the major functions like header compression, fragmentation and reassembly of packets and packet routing handled by it.

An innovative double Biquad patch antenna was introduced. It consists of two quad patch together. good directivity was achieved due to the corner reflector effect used in this design. The radiating elements are of four square with the side length equal to 1/4 mid band wavelength. The theoretical beam width can be varied widely with the reflection plane size and shape. Vertical Polarization is achieved from the position of orientation of the biquad.Biquad patch was implemented in microstrip antenna with three hard substrates such as Arlon, Neltec, and Fr4, High directivity,good gain and low return loss was achieved, and the resonant frequency obtained is from 5-10GHz, which is suitable for UWB application and the simulation was performed using HFSS.