We determine the bit-error rate (BER) of multilevel quadrature amplitude modulation (M-QAM) in flat Rayleigh fading with imperfect channel estimates. Despite its high spectral efficiency, M-QAM is not commonly used over fading channels because of the channel amplitude and phase variation. Since the decision regions of the demodulator depend on the channel fading, estimation error of the channel...

OFDM is being widely used in many communication systems for its ability to enhance the data rate and reduce the bandwidth. The paper gives a comparison of the performance of OFDM system using different modulation schemes under the influence of AWGN and Rayleigh fading channel. Simulations of OFDM signals are carried out with Rayleigh faded signals to understand the effect of channel fading and ...

The performance of Multiple Symbol Differential Detection applied to differentially encoded QPSK signals, is examined by simulation in the mobile radio channel with slow Rayleigh and Rician fading, and cochannel interference (CCI). Performance gains observed in the slow R i c h fading channel when compared to conventional differential detection, are maintained in the CCI environment. Using a si...

We discuss the performance of polar codes, the capacity-achieving channel codes, on wireless communication channel in this paper. By generalizing the definition of Bhattacharyya Parameter in discrete memoryless channel, we present the special expression of the parameter for Gaussian and Rayleigh fading the two continuous channels, including the recursive formulas and the initial values. We anal...

In this paper, the problem of estimating the optimal radio capacity of a single-cell spread spectrum (SS) multiple-inputmultiple-output (MIMO) system operating in a Rayleigh fading environment is examined. The optimisation between the radio capacity and the theoretically achievable average channel capacity (in the sense of information theory) per user of a MIMO single-cell SS system operating i...

In a mobile communication environment the channel is not time invariant and is slowly varying. This characteristic feature of the channel leads to a phenomenon called Fading. Fading channels induce rapid amplitude fluctuations in the received signal. If they are not compensated for then this will lead to serious performance degradation. In this paper simulations have been conducted to study the...

The coherent reception of Direct Sequence Code Division Multiple Access(DSCDMA) signals in a multipath fading channel is considered. The channel model assumes independent paths with Nakagami fading statistics. This model includes the Rayleigh channel as a special case and a reasonable model for a frequency selective fading channel. The bit error rate(BER) performance of a RAKE receiver under va...

Recent work on lattices matched to the Rayleigh fading channel has shown how to construct good signal constellations with high spectral efficiency. In this paper we present a new family of lattice constellations, based on complex algebraic number fields, which have good performance on Rayleigh fading channels. Some of these lattices also present a reasonable packing density and thus may be used...

The mutual information of a discrete time memoryless Rayleigh fading channel is considered, where neither the transmitter nor the receiver has the knowledge of the channel state information except the fading statistics. We present the mutual information of this channel in closed form when the input distribution is complex Gaussian, and derive a lower bound in terms of the capacity of the corres...

This paper considers the performance of pilot symbol aided channel estimation by investigating the achievable information rate in a fading channel. The channel is modeled as a time varying Rayleigh fading process whose dynamics are characterized by the normalized fading rate. The optimal fractions of bandwidth and power allocated to the pilot symbols are determined and presented in terms of the...