This paper analyzes the benefits of using a decision feedback equalizer (DFE) in the indoor radio environment and examines the results of performance predictions for different channel modelings. It is found that a QPSK/DFE modem with second-order diversity can operate at a data rate which is an order of magnitude higher than a QPSK modem without equalization. A given set of measured profiles of...

In this work performance of Gaussian Minimum Shift Keying (GMSK) modulation is compared with that of conventional QPSK and M-QAM modulation schemes. Use of unfiltered data stream for modulation results in a considerably large bandwidth in the modulated RF signal. Pulse shaping as a signal processing technique has gain grounds as a means to mitigate this problem. Gaussian filter along with squar...

In this paper, we have measured channel capacity for various communication system such as SISO, SIMO, MIMO with different modulation technique like BPSK, QPSK, 16-QAM and 64-QAM. In the proposed algorithm the Bit Error Rate (BER) is less compared to conventional algorithm. The proposed algorithm is suitable for fast speed traffic that is when the speed of the mobile is very high. We have measur...

The article deals with the problem of obtaining a qualitative assessment energy concealment degree radio signals. Energy is regarded as most significant form signal concealment, since designer transmitting devices has influence and greatest freedom in defining these properties. purpose to systematize available knowledge about methods order conduct mutual comparison characteristics various autho...

A new family of Nyquist pulses for coherent optical single carrier systems is introduced and is shown to increase the nonlinearity tolerance of dual-polarization (DP)-QPSK and DP-16-QAM systems. Numerical investigations for a single-channel 28 Gbaud DP-16-QAM long-haul system without optical dispersion compensation indicate that the proposed pulse can increase the reach distance by 26% and 19%,...

In this paper we experimentally demonstrate a novel, high phase-noise tolerant, optical dual polarization (DP) quadrature phase-shift keying (QPSK) communication system based on pilot-tone-aided phase noise cancellation (PNC) algorithm. Vertical cavity surface emitting lasers (VCSELs) with approximate 300 MHz linewidth are used as transmitters and local oscillators for coherent detection of opt...

This paper analyses frequency tracking characteristics of a complex-coefficient adaptive infinite-impulse response (IIR) notch filter used for suppression of narrow-band interference (NBI) with a randomly-varying frequency in a quadriphase shift keying (QPSK) modulated direct-sequence code-division multiple-access (DS-CDMA) communication system. The QPSK DS-CDMA signals are transmitted over a f...

For asynchronous sampled systems such as Polarization Division Multiplexed Quadrature Phase Shift Keying, (PDM-QPSK), phase and frequency of the sampling clock is typically not synchronized to the data symbols. Therefore, timing adjustment, so called clock recovery and interpolation, must be performed in digital domain prior to signal demodulation in order to avoid cycle slips. For the first ti...