Rajan Miglani

Statistical Analysis of FSO Links Employing Multiple Transmitter/Receiver Strategy over Double-Generalized and Gamma–Gamma Fading Channel Using Different Modulation Techniques

Abstract Free space optical (FSO) communication links have recently received lot of attention as high bandwidth and cost-effective access technique. However, the transmission medium, i. e. atmosphere, itself is a major spoilsport factor as atmospheric turbulence may lead to fading. The legacy of spatial diversity techniques which have already proven their worth as effective mechanism to counter channel fading in radio links has also been extended to FSO links in this paper. A mathematical model to evaluate error rate performance of FSO links over strong turbulent conditions using gamma–gamma and double-generalized gamma channel model for different modulation techniques has also been included. It was observed that higher modulation techniques such as binary phase shift keying (BPSK) and differential phase shift keying (DPSK) allow superior error performance as compared to on–off keying (OOK) links, and this performance further enhances with incorporation of spatial diversity techniques. However, across different diversity options, explained in this paper, BPSK–MISO links were the best choice for turbulent conditions.

Energy conservation and collision avoidance by controlled access protocol in WSN

Energy conservation is one of the major aspects in Wireless Sensor Networks since it impacts the network lifetime. In this paper; we focus on the energy conservation in the MAC protocol which is basically used for the transmitting of data/selecting the channel for transmission. The energy conservation process is carried out by using the controlled access protocol. The paper emphasizes on operation of primary and secondary nodes in the polling mechanism and MACA-BI to carry out transmission in proper manner without any delay factor involved. The lifetime of a node and network of proposed technique is compared with the network using Random Access Protocol by considering the power consumed by each node under various modes.

Gain profile analysis in fiber optical parametric amplifiers using SBS technique

In this paper experimental verification of optical fiber based parametric amplification has been studied over different modulation formats. Based on principle of parametric amplification, which is essentially a non linear phenomena, these fiber amplifiers offer discrete amplification along with greater use of bandwidth without any major compromise on usable gain and vice versa. We have demonstrated the gain profile of fiber optical parametric amplifier using SBS (Stimulated Brillouin Scattering) control mechanism which is based on SBS power pump, which in turn determines the gain of lumped amplifier. Different modulation formats like amplitude modulation, frequency modulation and phase modulation were investigated, both with and without the parametric amplification over given length of fiber. During performance evaluation it was observed that FM and PM modulated data responded with considerable increase in gain with activation of SBS pump, while the similar gain improvement was found to be missing in AM modulated data.