Modulation plays an important role in transmission of signals from transmitter to receiver in all communication systems and the performance of digital modulation systems is of the most important key factors to achieve the best results of the communication process . This paper presents a comparative study of some performance parameters or performance metrics of a digital communication system wit...

We demonstrated a delay-line interferometer (DLI)-based, optical-signal-to-noise ratio (OSNR) monitoring scheme of 100  Gbit/s polarization multiplexed quadrature-phase-shift-keying (PM-QPSK) four-channel WDM at 50-GHz International Telecommunication Union (ITU) grid with <0.5  dB error for signals with up to 26 dB of actual OSNR. We also demonstrated data format transparency and baud rate tuna...

This paper proposes a novel phase recovery method for Turbo-coded QPSK systems. The phase estimation is combined with the turbo decoding instead of applying separate synchronisation prior to the Turbo decoder. It is achieved through Maximum Likelihood Estimation (MLE) which employs the extrinsic information obtained from the turbo decoder. Look-up tables are pre-computed to reduce the computati...

Wireless communications using Multiple-Input Multiple-Output (MIMO) links has emerged as one of the most significant breakthroughs in modern communications because of the huge capacity and reliability gains promised even in worst fading environment. This paper presents the optimized behaviour of MIMO systems over Rayleigh and Rician Fading channel environments. MIMO transmission systems are inv...

A phase-sensitive four-wave mixing (FWM) scheme enabling the simultaneous conversion of the two orthogonal quadratures of an optical signal to different wavelengths is demonstrated for the first time under dynamic operation using a highly nonlinear optical fiber (HNLF) as the nonlinear medium. The scheme is first optimized with respect to the power levels and phases of the four phase-coherent p...

This paper is concerned with the bit error probability performance of rate lL! convolutional codes in conjunction with quaternary phase shift keying (QPSK) modulation and maximum likelihood Viterbi decoding on fully interleaved Rician fading channels. Applying the generating function union bounding approach, an asymptotically tight analytic upper bound on the bit error probability performance i...

A hybrid data transmission technique for multimedia satellite broadcasting is proposed. The main-channel data and sub-channel data are simultaneously transmitted using QPSK modulation and 2ASK modulation, respectively, but the latter modulation timing is offset by half the main-channel QPSK symbol length in time. The BER performance in a Gaussian channel, the transmission bandwidth, and the tra...

The emerging need for high data rate wireless services has raised considerable interest in space-time coding. In this work, we propose a systematic code construction method that jointly considers diversity advantage and coding advantage for an arbitrary number of transmit antennas and any memoryless constellation. Our approach is to directly assign channel symbols to transmit antennas at differ...

Multiple Input Multiple Output (MIMO) systems has provide high transmission data rate without increasing transmitting power for wireless communication systems. The performance can be further improved by properly estimating the channel at the receiver side. In this paper, investigation on various channel estimation techniques for MIMO-OFDM has been done and a new approach based on time-domain in...

Polarization-insensitive (PI) phase-transmultiplexing (PTM) of a 10-Gb/s return-to-zero ON-OFF keying (RZ-OOK) pump and a 10-Gb/s RZbinary phase-shift keying (RZ-BPSK) probe to 20-Gb/s RZ-quadrature-PSK (RZ-QPSK) has been successfully demonstrated for the first time in a passive, birefringent AlGaAs waveguide, utilizing PI cross-phase modulation (PI-XPM). For differential QPSK (DQPSK)-detection...