Bijayananda Patnaik

Inter-satellite optical wireless communication system design and simulation

An ultra-high bit-rate inter-satellite optical wireless communication (IsOWC) system is proposed in thisstudy. The system is designed and simulated up to the bit-rate of 400 Gbps. The proposed system is a non-diffused link or line-of-sight setup, which uses coherent optical quadrature phase-shift keying (QPSK) modulation technique. The performance of the system is analysed in terms of Q -factor, bit-error rate, eye opening and so on. The coverage distance observed with an input power level of 30 dBm for a bit-rate of 400, 160 and 100 Gbps are 4767, 7542 and 9532 km, respectively. Finally, the maximum bit-rate that can be communicated, for inter-satellite link at different orbits such as low-Earth orbit, medium-Earth orbit and geostationary Earth orbit are presented. To the best of the authors knowledge for the first time they have proposed a novel QPSK modulation technique for the design of IsOWC system for achieving higher coverage distance and data rate, which was not been addressed in any current or earlier publications.

Optimization of Four Wave Mixing Effect in Radio-over-Fiber for a 32-Channel 40-GBPS DWDM System

In this paper, we have discussed in detail the four wave mixing (FWM) effect of dense wavelength division multiplexing (DWDM) in Radio-over-Fiber (RoF) system. A 32-channel 40-Gbps system is considered. FWM effect for various channel spacing, input power level, effective fiber area and modulation formats are analyzed. Different schemes for minimizing these effects are discussed for the first time. Considering all these effects, an optimized DWDM setup is designed using single parameter optimization (SPO) technique.

Design and study of high bit-rate free-space optical communication system employing QPSK modulation

We have proposed Free–Space Optics systems (FSO), which are Diffused Link (DL) and Line–of–Sight (LOS) setup using Quadrature Phase Shift Keying (QPSK) technique. The optimized coverage distance, for an input power level of 5 dBm and data rate of 1 Gbps, is found to be 1036.307m and 2388.725km for DL and LOS setup respectively. Also, the proposed system is simulated for 1.25 Gbps, 2.5 Gbps, 10 Gbps, 40 Gbps and 100 Gbps with free–space attenuation of 200 dB/km using Optisystem 9.0 and Matlab 7.9.0. The system will be useful where the coverage area, performance, security and cost–savings are critical factors.

Long-haul 64-channel 10-Gbps DWDM system design and simulation in presence of optical Kerr's effect

In this paper, we have analyzed a 64-Channel 10-Gbps dense wavelength division multiplexing (DWDM) system. The proposed design is a high capacity 640 Gbps system with centre frequency of 193.1THz. The system is analyzed for simple return to zero (RZ) modulation format and the advanced, modified duo-binary return to zero (MDRZ) modulation format. MDRZ has been found to be the best performance over RZ modulation format for long-haul high capacity optical communication system (>500Km). Besides the above modulation formats the system performance is also analyzed for symmetrical dispersion compensation scheme with a Channel spacing of 50 GHz. For the best of the Authors knowledge this is the first that such a high capacity system performance is simulated and reported for a channel spacing of 50 GHz. The proposed MDRZ system with symmetrical dispersion compensation scheme provides good Q-value (>13.12), eye opening and bit error rate (BER) performance for all the channels, for a coverage distance of 1200Km.

Bit Error Rate Performance Analysis of Hybrid Subcarrier Intensity Modulation-Based FSO with Spatial Diversity in Various Weather Conditions

Abstract In this paper, we study the performance improvement of free space optical (FSO) communication system with spatial diversity techniques employing hybrid pulse position modulation-binary phase shift keying-subcarrier intensity modulation (PPM-BPSK-SIM). The involvement of multiple photo-detectors in diversity based FSO systems offers an effective way to overcome scntillation. In this paper, we have simulated the bit error rate (BER) with respect to different parameters like average SNR, link distance at various weather conditions. The simulation results are verified in Matlab environment with the mathematical analysis. The simulation results show that higher order single input multiple output (SIMO) system achieves better BER performance and hybrid PPM-BPSK-SIM has significant improved performance than the common modulation schemes like PPM, BPSK-SIM.

Ultra High Bit-rate Fiber Optic Hybrid (WDM and TDM) Communication System Design and Simulation

An ultra-high bit-rate fiber optic hybrid system is proposed in this work. The proposed system utilizes the advantages of both wavelength division and time division multiplexing techniques. The performance has been investigated for various advanced data formats such as carrier-suppressed return-to-zero (CSRZ), duo-binary return-to-zero (DRZ) and modified duo-binary return-to-zero (MDRZ). MDRZ format is proved to be the best among all. The proposed system performance has been investigated at various bit rate of 10Gbps, 40Gbps and 100Gbps, for over the selected transmission lengths of 1650 Km, 400 Km, 100 Km respectively.

Block and Fast Block Sparse Adaptive Filtering for Outdoor Wireless Channel Estimation and Equalization

Rayleigh’s distribution is mainly used when fading wireless medium does not have proper line of sight (LOS) path and is dominated by a large number of non-line of sight (NLOS) paths due to reflections of the received signal. Also because of relative motion of the base station and mobile station, a random frequency shift is generally introduced in the carrier, which can be realized in terms of Doppler spread. In case of Rayleigh’s fading channels, there are two critical problems for receiver design that is accurate estimation of channel coefficients followed by mitigation of channel impairments like inter symbol interference and fading in presence of user mobility. The accuracy of estimated channel state information is really crucial to design robust equalizer for reconstruction of bit sequence and the equalizer performance is affected by the fading rate and Doppler spread. The main research contributions of the paper is based on the exploitation of underlying sparseness of block adaptive filters through

A Comparative Analysis of Different Modulation Techniques Based on Subcarrier Intensity Modulation in Free Space Optics Using Log-Normal Turbulence Model

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