IJWMT Vol. 6, No. 3, May. 2016
Cover page and Table of Contents: PDF (size: 310KB)
The usability of Mobile devices and portable computers has been increased very rapidly. The main focus of modern research is to handle the big data in Mobile and pervasive computing. This paper gives an overview of Mobile Data Challenge which was a smart phone based research done by Nokia through Lausanne Data Collection Campaign. The Mobile Data Challenge was introduced when the amount of mobile data was seen to be increased very much in a short period of time. The rise of big data demands that this data can be accessed from everywhere and anytime. For handling such a huge amount of data e.g. SMS, images, videos etc, this data must be compressed for easy transmission over the network. It also helps in reducing the storage requirements. There are various techniques for the compression of data that are discussed in this paper. SMAZ and ShortBWT techniques are used to compress SMS. JPEG and Anamorphic Stretch Transform are used to compress the images.[...] Read more.
Wireless Sensor Networks (WSNs) are typically formed by collaboration of the large amount of partial sensor nodes, which are connected through wireless medium. In wireless sensor network, security is an essential aspect because of its usage in applications like monitoring, tracking, controlling, surveillance etc. Secure communication is extremely crucial in delivering vital information accurately and on the time through resource constraint sensor nodes. In this paper, our contribution is threefold. Firstly, we have summarized the network layer routing attacks on WSNs. Secondly, we have provided taxonomy of secure routing protocols of WSNs. Thirdly, we have provided a qualitative comparison of existing secure routing protocols. Results show that most of the existing secure routing schemes are not very efficient due to various reasons like high-energy consumption, and large communication overhead.[...] Read more.
This paper presents a microstrip patch antenna incorporated with electromagnetic band gap (EBG) structure on substrate and defected ground structure (DGS) in the ground plane. Electromagnetic Band Gap materials are artificially engineered structures that improve the performance of the patch antennas. It is manifested that applications of both EBG and DGS outcomes in the remarkable improvement of return loss level from -20.2dB to -31.5dB and bandwidth from 155MHz to 202 MHz respectively. The most fascinating characteristic of the proposal is the capability of increasing the gain, directivity and the total efficiency of the antenna without affecting the other essential parameter like bandwidth which makes the designed antenna applicable for Radio Frequency portable devices operating at 6.1 GHz.[...] Read more.
The main focus of this paper is to study and analyze how the performance of rectangular U slot antenna is affected by the variation of U slot position. The work presented herein is a simulation based study. Experimentally, it has been revealed that variations in parameters such as the width and length of the U-slot, height and size of the patch, probe size and location as well as substrate permittivity can dramatically change the antenna's behavior. Till date, no analytical methods have been developed that accurately relate the complex relationships between the antenna dimensions and individuality. This paper describes the behavior of antenna with change of U slot position. A numerical solution is obtained by varying the various positions of U slot along all the axis and the effect of U slot position on various antenna output parameters is analyzed.[...] Read more.
For the transmission of signals at higher frequencies, there is a requirement for extension of a higher capacity system and higher bandwidth in wireless communication systems. The use of smart antenna increases the system performance with the arrangements of its constituent elements and digital signal processing capacity. Analysis and design of smart antenna arrays can be performed for wireless communication systems using various methods and approaches. One of these methods is circular pin-fed linearly polarized patch antenna has been adopted in this research work.
This work presents the design and analysis of smart antenna by circular pin-fed linearly polarized patch antenna. Patch antenna is a very prominent antenna in the microwave frequency spectrum due to its simplicity and compatibility with the printed circuit board (PCB) technology.
A dual band linear polarized micro-strip antenna is designed and simulated to obtain electronic circuit miniaturization of an antenna in high speed wireless local area networks (IEEE 802.11a standard). The proposed antenna contains a substrate layer (FR-4 lossy) with a dielectric constant of 4.4 and there is a circular patch on the upper layer of the substrate. The coaxial probe feed is used to excite the desired antenna which reduces the spurious radiation and hence obtained good efficiency. It is shown that using cavity model 20% excess bandwidth can be achieved while maintaining the lower size of the antenna. An 'E' shaped slot is introduced in the radiating patch to obtain dual band resonance frequency with maximum current distribution on the surface. Finally the simulated results using Computer Simulation Technology (CST) microwave studio 2009 in this design is compared with manual computation results which are found to be suitable for WLAN applications.[...] Read more.
In this paper, a simple method for designing a circular polarized antenna using chiral metamaterial is presented. The antenna proposed in this paper consists of conventional linear polarized Rectangular Microstrip Patch Antenna (RMPA) and cover of bilayer twisted cross wire Chiral Metamaterial (CM). The placement of CM cover over the linearly polarized RMPA changes its polarization from linear to circular and the antenna produces a left handed circularly polarized wave at resonant frequency of 6.24GHz with axial ratio of 0.46 dB. Investigation of performance parameter of proposed antenna and parameters of unit cell of CM is also presented in the paper.[...] Read more.
Smart grid implementations rely on the real-time monitoring and controlling of the electric power grid. To achieve real time there is need for a messaging system with minimum delays. After mentioning latest implementations and their delays we analyze the role of the different communication protocols needed within smart grids and we describe key factors to a message's delay. Taking into consideration a packet's speed constraints we then calculate a radius, within which, the ETSI communication requirements for smart grids are satisfied.[...] Read more.