In this paper we compare different transmultiplexer structures with respect to the ISI/ICI occuring for typical time–invariant channels. In particular we consider wavelet–type, Gabor-type (the class containing OFDM and DMT) and Wilson-type (offset-QAM/OFDM) transmultiplexer. We present both theoretical results (based on a recently developed perturbation theory of coherent Riesz bases) and numer...

Error free transmission is the main aim of wireless communication. However nowadays with the increase in multimedia services there is a demand for ever increasing data rates. To reduce the bit error rate forward error correction methods (FEC) methods are now employed. In this paper we compare the BER performance of 16-QAM and 64-QAM modulation techniques with and without interleaving process. A...

Welch and Sidelnikov lower bounds on the maximum nontrivial correlations of complex signal sets apply to the constrained case of uniform signal energy and have long been used as a benchmark for testing the merit of signal sets in the design of good CDMA sequence families. Welch’s lower bound is generalized here to the arbitrary signal energy case and applied to CDMA over QAM modulation. The gen...

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%,...

We present a low complexity encoder and mapper for wireless multiple-input multiple-output (MIMO) systems. The BLAST (Bell Laboratories Layered Space-Time) algorithm is enhanced by a dedicated iterative QAM demapper with antiGray code. At the the transmitter a low complexity convolutional encoder and a QAM mapper with anti-Gray code are used, whose EXIT (Extrinsic Information Transfer) chart ar...

This paper explores the use of Higher Order Statistics for the recovery of the carrier phase and frequency offset in a QAM receiver operating in an additive Gaussian noise channel. The technique is based on newly established properties of the 3 and 4-order cumulants of the demodulated QAM signal. The resulting method may be thought of as higher-order extension of the second order automatic freq...

We investigate 128-level set-partitioning quadrature amplitude modulation (128-SP-QAM) experimentally and compare the performance to polarization-multiplexed 16QAM both at the same bit rate and at the same symbol rate. Using a recirculating loop we study both single channel and wavelength-division multiplexing (WDM) transmission and demonstrate a reach of up to 2680 km at a bit-error rate of 10...

The fast development of modern communication techniques, the demand for reliable high data rate transmission is increased signification, which stimulate much interest in modulation technique. The QAM is one of the adaptive modulation techniques that are commonly used for wireless communications. Different order modulations allow sending more bit per symbol and thus achieving higher throughput o...

Recently, the 3-D CAP system was introduced as a mod-iication to the conventional 2-D CAP. This paper makes two contributions in the context of the 3-D CAP system. First, the QAM equivalent for the three-dimensional case is introduced by extending the 2-D complex notation into a 3-D vector notation. The deenition is a modiication of the well known quaternions. Second, the 3-D QAM ltering is red...

For improving the equalization performance of higher-order QAM signals, orthogonal Wavelet transform dynamic Weighted Multi-Modulus blind equalization Algorithm based on the Dynamic Particle Swarm Optimization(DPSO-WWMMA) is proposed. In this proposed algorithm, dynamic particle swarm optimization algorithm and orthogonal wavelet transform are introduced into dynamic Weighted Multi-Modulus blin...