Insophisticated situations coming from developing multimedia applications and the exponential increase in the number of smart sensors and devices, future wireless networks will ensure high reliability, low latency, scalability, as well as better quality-of-service.Optical wireless communication (OWC) becomes more important because it can take advantage of the light medium's unique selling points over RF, such as immunity to electromagnetic interference (EMI), ultra-high capacity, the ability to communicate wirelessly through water, and the ability to provide additional security. Dual polarization (DP) enabled multilevel modulations in inter satellite optical wireless communication (Is-OWC) are potential and capacity building techniques to cope up with bandwidth explosive demands. Therefore, inthis work, a reach enhanced single channel Is-OWC is proposed using Double Sideband Suppressed (DSS) dual polarized (DP) Quadrature phase shift keying (QPSK) modulation. Spectral efficiency of carrier is improved through DSS technique using Mach-Zehndar modulator (MZM) and millimeter wave (mm- wave). Further, pulse width reduction, nonlinear effects suppression, carrier phase estimation (CPE) and frequency offset estimation (FPE) is performed by Digital signal processor (DSP) in coherent receiver of PDM-QPSK. Performance comparison of DP-QPSK and DSS-DP-QPSK is performed at different link lengths in terms of log BER and error vector magnitude (EVM%). Results revealed that proposed system i.e., DSS-DP-QPSK at 160 Gbps data rate covers 44,000 km Is-OWC distance with acceptable log BER as compared to 40,000 km in DP-QPSK due to improved spectral efficiency of carrier spectrum of proposed system.

This paper provides a review of various inter carrier interference cancellation methods used in Orthogonal Frequency Division Multiplexing (OFDM) in the downlink of Long Term Evolution (LTE) and in many other applications. It contains the analysis of different methods, their explanations, areas of implementation, advantages, drawbacks and finally a comparison of the methods has been made. The paper is based on the fact that during OFDM reception, the overlapping frequencies interfere due to various reasons and different methods have to be applied to avoid interference among the frequencies for a proper reception at the receiver.

Mobile Ad-Hoc Networks (MANETs) are autonomous and decentralized wireless systems. Mobile Ad hoc Network is a collection of mobile nodes in which the wireless links are frequently broken down due to mobility and dynamic infrastructure. Routing is a significant issue and challenge in ad hoc networks. Many Routing protocols have been proposed so far to improve the routing performance and reliability. This research paper describes the characteristics of ad hoc routing protocols Ad-hoc On Demand Distance Vector Routing (AODV), Optimized link State Routing (OLSR), Temporally Ordered Routing Algorithm (TORA), Dynamic Source Routing (DSR), Destination-Sequenced Distance-Vector Routing (DSDV) based on the performance metrics like packet delivery fraction, Average delay, Normalized Routing load, Throughput and Jitter under low mobility and low traffic network as well as under high mobility and high traffic network. Results show that AODV has maximum throughput under low traffic and DSDV has maximum throughput under high traffic. As network becomes dense OLSR, DSR and DSDV perform well in terms of Throughput than AODV and TORA. TORA performs well in dense networks in terms of packet delivery fraction but at the same time Normalized Routing load of TORA is maximum among all the protocols in both the networks. DSDV has least Normalized Routing load in both low and high traffic. OLSR and DSDV give the least Jitter and Average Delay in both networks.

In this paper, Coded Orthogonal Frequency Division Multiplexing (COFDM) based Radio over Fiber (RoF) system is simulated (for different bit rates) for different modulation techniques to observe impact on system parameter [quality factor (Q)]. Influence of increasing bit rates has been observed for 2 km long linear multimode fiber. To reduce dispersion due to multimode fiber, convolutional encoder (code rate ½, generator polynomial 1338, 1718) and viterbi hard decision decoding algorithm are chosen for simulative model of COFDM based RoF system. Transmission of 32 sub-carriers with externally modulated continuous wave laser source gave satisfied results for Q values.