In this paper, we present a two-user cooperative automatic repeat request (C-ARQ) protocol which combines cooperative diversity at the physical layer and ARQ at the link layer. In this scheme, distributed Alamouti space-time block coding (DASTBC) is applied to achieve cooperative diversity, and ARQ is used to improve the data link layer reliability. To analyze the performance of the proposed pr...

In this paper, three new ultra wideband (UWB) communication systems with quadrature-phase shift keying (QPSK) impulse modulation are proposed. First, direct-sequence (DS) multiple-access scheme is applied. The second proposed system is based on time-hopping (TH) multiple-access scheme. The last proposed system applies TH multipleaccess scheme with QPSK impulse modulation and pulse position modu...

Modulation plays an important role in transmission of single from transmitter to receiver in all communication systems. But it is vital in wireless communication and a lot of communication features including (data rate, error rate, symbol rate, bandwidth etc) depends upon it. In NS2 wireless network simulation BPSK is used for digital encoding and modulation of data [1,2]. The BPSK method is us...

We present WDM multicasting based on dual-pump four-wave mixing in a 3-mm long dispersion engineered silicon waveguide. One-to-six phase-preserving WDM multicasting of 10-Gb/s differential phase-shift-keying (DPSK) data is experimentally demonstrated with bit-error rate measurements. All the six multicast signals show error-free performance with power penalty less than 3.8 dB.

A noncoherent Gaussian minimum phase-shift keying (GMSK) detector using differential phase detection combined with the soft-output Viterbi algorithm (SOVA) is presented. This approach overcomes the severe intersymbol interference (ISI) of GMSK signals with low BtT . Unlike conventional detectors the SOVA produces soft-decision bits resulting in larger coding gains in subsequent convolutional de...

In this paper we introduce the PCPH (Pseudo-Chaotic Phase Hopping) telecommunication scheme, which is obtained by combining pseudo-chaotic encoding with N -ary phase shift keying. For this system, we address the problem of finding the optimal constellation labeling in order to minimize the error probability.

This work investigates the effect of phase fluctuation averaging on phase fluctuation induced by intrachannel four-wave mixing (IFWM) in highly dispersed differential phase-shift keying transmission systems. Through repeatedly averaging the phase fluctuations of adjacent pulses, a simple analytical model and numerical simulation revealed that the IFWM-induced differential phase fluctuation is s...

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...

With the increasing demand in communication, it has become necessary to give better and efficient service to users by using better technique. This paper analyse the bit error rate, for different modulation schemes such as Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK. By Choosing a reliable modulation scheme and better coding technique the enhancement of the performance ...

In this paper, we investigates the effects of two different modulation schemes for image transmission using an OFDM (Orthogonal Frequency Division Multiplexing) transceiver. The main aim is to evaluate the performance between 16PSK (Phase Shift Keying) and 16QAM (Quadrature amplitude modulation) in context of BER (Bit Error Rate) in AWGN (Additive White Gaussian Noise) channel. We evaluate the ...