Nonlinearities in optical fibers deteriorate system performances and become a major performancelimiting issue. This article aims to investigate the compensation of nonlinear distortions in optical communication systems based on different wavelength propagations over few-mode fiber (FMF). The study adopted Space Division Multiplexing (SDM) based on decision feedback equalizer (DFE). Various transmission wavelength of the FMF system is applied to mitigate the attenuation effect on the system. In this paper, different wavelengths (780, 850 and 1550 nm) are used in SDM. Extensive simulation is performed to assess the attenuation and Bit Error Rate (BER) in each case. The results show that the wavelength of 1550 nm produces higher power and less attenuation in the transmission. Furthermore, this wavelength produces the best distance with less BER compared to 780 nm and 850 nm wavelengths. Moreover, the validations show improvement in BER and eye diagram.

Energy and latency are the significant Quality of Service parameters of ad hoc networks. Lower latency and limited energy expenditure of nodes in the ad hoc network contributes to a prolonged lifetime of the network. Reactive protocols determine the route to the destination using a route discovery process which results in increased delay and increased energy expenditure. This paper proposes a new technique of route discovery, Dynamic Blocking Expanded Ring Search (DBERS) which minimizes time delay and energy required for route discovery process. DBERS reduces energy expenditure and time delay occurring in the existing route discovery techniques of reactive protocols. The performance of DBERS is simulated with various network topologies by considering a different number of hop lengths. The analytical results of DBERS are validated through conduction of extensive experiments by simulations that consider topologies with varying hop lengths. The analytical and simulated results of DBERS are evaluated and compared with widely used route discovery techniques such as BERS, BERS+. The comparison of results demonstrates that DBERS provides substantial improvement in time efficiency and also minimizes energy consumption.

The welcome and adaptation of optical wireless technology by the modern era has brought forward the concept of an inter-satellite free-space optical communication system. In the present work, I study the combined effect of selection of different operating wavelengths and detector types along with the pointing errors at the transmitter and receiver side on the performance of an inter-satellite free-space optical link. The link performance has been optimized by measuring and analyzing the bit error rate and quality-factor of received signal under different scenarios. Performance of the inter-satellite link has also been investigated considering different modulation formats and data rates for LEO and MEO distances.

This paper investigates the differential binary modulation for decode-and-forward (DF) based relay-assisted free space optical (FSO) network under the effect of strong atmospheric turbulence together with misalignment error (ME). The atmospheric fading links experience K-distributed turbulence. First we derive novel closed form expression for average bit error rate (BER) and outage probability (OP) in terms of Meijer’s G function. Further, the OP of differential DF-FSO system with multiple relays is derived. We also analyze the asymptotic performance for the sake of getting the order of diversity and the coding gain. The power allotment term is utilized to examine the effect of different power allotment techniques on BER and OP. The simulation results have been used to validate the derived analytical results.

Low Density Parity Check (LDPC) is a channel coding technique widely utilized in the 5G New Radio standard, it is of utmost importance in facilitating proficient and secure communication in noisy environments by effectively minimizing errors during data transmission. It is primarily used in the 5G New Radio (NR) standard for encoding user information on the Physical Downlink Shared Channel (PDSCH). The necessity to satisfy the increasing expectations for throughput, latency, and dependability led to the decision to deploy LDPC codes for user data, especially in the enhanced mobile broadband (eMBB) and ultra-reliable and low-latency communications (URLLC) scenarios of 5G networks. The present system proposes the use of NRLDPC codes for the purpose of transmitting data across a lognormal multipath fading channel model in the presence of AWGN. Wireless communication channels often use a lognormal multipath fading channel model, where the received signal experiences both multipath fading and lognormal shadowing. The research investigates the effectiveness of NR-LDPC coding in improving QAM-OFDM system performance by analyzing two rate-compatible base graphs and comparing their effectiveness with an uncoded system. This analysis is crucial for optimizing communication network design, especially in scenarios where the integrity of data is of utmost importance. We introduce a new method to improve the 5G NR LDPC code capability under lognormal fading conditions. This approach develops a layered Min Sum (LMS) algorithm to provide enhanced error correcting capabilities. The developed and implemented decoding algorithm represents a significant advancement over traditional detection methods. The outcomes of the simulation provide evidence of the effectiveness of the proposed NR-LDPC coding techniques in terms of their error correction and identification capabilities. In addition, the developed LMS decoding algorithm has been shown to significantly decrease the BER of the system.