in this paper, for the purpose of investigating horizontal sound propagation, based on the results obtained from practical measurements in the strait of hormoz and available data on sound speed variations at different depths, a comprehensive model for shallow water multipath underwater acoustic channel is presented. mathematical modeling of multipath effect is based on ray theory and the image ...

The exact expressions for the symbol error probability (SEP) of hybrid selection maximal ratio combining wireless systems for quadrature phase shift keying (QPSK) is derived and analyzed in multipath fading environment. Independent rayleigh fading diversity branch is assumed for analysis with equal Signal-to-Noise ratio averaged over the fading channels and coherent detection of quadrature phas...

We experimentally demonstrate on-chip mode-selective wavelength conversions based on the degenerate four-wave mixing (FWM) nonlinear effect in a few-mode silicon waveguide. A multimode waveguide with tapered directional coupler based mode (de)multiplexers is designed and fabricated. Using signals with advanced modulation formats all-optical wavelength conversions of 102.6-Gb/s OFDM-QPSK signals...

This paper presents performance comparison of various modulation techniques in Rayleigh fading channel. In the comparison, the space time coding has been used. The performance comparison are made on the basis of bit error rate(BER) and symbol error rate(SER) performance matrices over Rayleigh fading channel with BPSK,QPSK,8PSK and QAM modulation technique. The comparison results shows that in R...

The performance of QPSK and QAM system that are used to encode the data stream in wireless communications. In order to choose the most suitable modulation, several criteria such as power efficiency, bandwidth efficiency, and bit error rate are used for evaluation. This paper focuses on error performance of phase modulation and amplitude modulation schemes on the method to reduce bit error rates...

With the increasing concentration in digital age, it is required to set up an inter-satellite optical wireless communication (IsOWC) that can support ultra-high bit rate. Here the proposed IsOWC is implemented using Non-coherent Continuous Phase Frequency Shift Keying (CPFSK), Differential Quadrature phase shift keying (DQPSK), Coherent Medium shift keying (MSK) and Dual Polarization Quadrature...

In this paper, the error performance of an MC-CDMA system is analysed with the help of Quadrature Phase shift Keying (QPSK) as the modulation technique mixed up with Additive White Gaussian Noise (AWGN) in the Rayleigh channel. CDMA suffers with the problem of selective frequency diversity during the downlink process. Orthogonal Frequency Division Multiple Access (OFDMA) techniques combine with...

In this paper we numerically investigate nonlinear impairments in a WDM system with mixed PM (D)QPSK and OOK channels. First we analyze the dependence of XPM and XPolM on SOP and baud rate in absence of PMD. In this case we find that the nonlinear impairments are highly dependent on relative SOP between the PM (D)QPSK and neighbouring OOK channels. The dependence on relative SOP is more pronoun...