Mahmoud A. Smadi

SVD-based joint azimuth/elevation estimation with automatic pairing

In this paper, a joint azimuth/elevation estimator with automatic pairing is developed. Two-dimensional (2-D) angle of arrival (AOA) estimation is useful in space processing systems and wireless location systems that employ AOA technology. The estimator makes use of a special setup of the received signal at an L-shaped antenna array element organized especially for the estimation process. The estimator is based on applying the singular value decomposition (SVD) algorithm to a cross-correlation matrix that is constructed from both arrays of the L-shaped structure. The proposed method avoids the computational burden of the complex pair-matching procedure. Simulations of the proposed method are shown to assess its performance.

Performance analysis of generalized-faded coherent PSK channels with equal-gain combining and carrier phase error

A new method is developed to analyze the performance of partially coherent PSK systems in wireless channels with equal-gain combining diversity receiver. Two performance criteria are considered: the average bit error probability and the probability distribution of the combiner SNR (SNR reliability). Tikhonov-distributed phase error processes are assumed and generalized fading channels including Rayleigh, Rician, and Nakagami-m are investigated. We evaluate the detection loss suffered by the carrier recovery for different SNR reliability levels when BPSK and QPSK systems are used in wireless channels. The analysis is based on a convergent infinite series for the distribution of the sum of random variables. The convergence rate of the proposed series is investigated and the analytical results are presented along with providing results obtained by simulation.

A high performance data integrity assurance based on the determinant technique

Data integrity is an important aspect of storage and network security. The reality is that no security strategy is achieved without assuring data integrity. Data assurance provides reliability which is a prerequisite for most computer systems and network applications. This paper proposes a new technique for improving the detection of data integrity violations. The proposed technique is based on the Check Determinant Factor (CDF) in measuring data integrity assurance. It involves appending of a Determinant Factor (DF) for each data matrix before storing or transmitting the series of data. This DF is recomputed at the retrieved stage to ensure data integrity. Simulation results show that the new method outperforms the traditional methods such as Hamming code and RAID methods.

Performance analysis of QPSK system with Nakagami fading using efficient numerical approach

An efficient numerical method is developed to analyze the bit error rate of PSK Nakagami-m fading systems with imperfect carrier recovery. We evaluate the detection loss suffered due to the carrier recovery for different rms phase error values when coherent QPSK system are used in wireless channels. Our results are useful in the design of practical systems and will enable designers to determine the phase precision of PSK systems in wireless environments.

Analytical study on the effect of cochannel interference on partially coherent diversity systems

In this paper, we study the effect of cochannel interference (CCI) on the performance of partially coherent BPSK and QPSK in uncorrelated L-branch equal-gain combining systems. We consider a generalized propagation model wherein the desired and interfering signals undergo Nakagami-m or Rician fading with different amounts of fading severity. Further, the interfering signals are assumed to be asynchronous symbol timing with the desired signal, so that the effect of cross-signal intersymbol interference (ISI) is taken into account. Using a convergent Fourier series method, we derive extensive analytical results for the average bit error probability and the SNR gain penalty caused by the interference signals for different signal to-interference ratio levels. The numerical results presented in this paper demonstrate the system performance under very realistic propagation and detection conditions including CCI, carrier phase error recovery, cross-signal ISI, generalized fading channels, and AWGN. Hence our results are expected to be of significant practical use for such scenarios.

Simulation and Numerical Analysis of Wireless PSK Systems with Imperfect Carrier Phase Recovery

Abstract The bit error probability (BEP) of binary and quaternary PSK (BPSK and QPSK) signals over Rayleigh fading channel with imperfect carrier-phase recovery is derived. The channel is assumed to be slow and frequency-nonselective in which the received signal is constant over at least two symbol intervals. Numerical values for the average BEP are obtained by integrating the conditional BEP expression over the carrier-phase error distribution. The resultant integrands have only elementary functions, such as exponentials and algebraic power functions and can, therefore, be explicitly evaluated to any degree of accuracy. The accuracy of this approach is verified through proposing an efficient quazi-analytical simulation technique.

Postdetection EGC diversity receivers for binary and quaternary DPSK systems over fading channels

Binary and quaternary differential coherent phase-shift keying schemes are widely used in digital wireless systems. In this paper, we derive a simple expression for the bit error rate performance of such schemes under postdetection equal-gain combining and fading channels. The analysis is based on a convergent infinite series for the probability density function of sums of random variables that has been derived using a Fourier series approximation method. Several fading conditions including arbitrarily correlated Nakagami-m, and independent Ricean slowly varying channels are investigated. The analytical study is also accompanied by using simulation techniques.

Useful bounds for the BEP of partially coherent faded PSK signals

Useful upper and lower bounds are presented for the average bit-error probability (BEP) of uncoded partially coherent BPSK and QPSK systems. For the first time, the bounds are derived taking into consideration wireless fading impairment. The bounds are shown to be tight and easy to evaluate for phase error noise parameters likely to be encountered in practice and for SNR that are needed in moderate fading environments. A precise relationship between the lower bounds and the average degradation caused by the carrier phase error are given. Also, the analysis of the upper bound establishes an expression for the irreducible errors due to imperfect phase recovery for a coherent QPSK system. The accuracy of both bounds is illustrated by comparing the bound results to those obtained by more complex exact series analysis.

Simplified bit error rate evaluation of Nagakami- m PSK systems with phase error recovery

An efficient analytical and simulation techniques were developed to analyze the bit error rate of PSK Nakagami-m fading systems with imperfect carrier recovery. We evaluate the detection loss due to the carrier recovery for different rms phase error values when coherent BPSK and QPSK systems are used in wireless channels. Our results are useful in designing practical systems and will enable designers to determine the phase precision of PSK systems in wireless environments. Copyright

Analysis of partially coherent PSK systems in wireless channels with equal-gain combining

A new method has been developed to analyze the performance of partially coherent PSK systems in wireless channels with equal-gain combining. We evaluate the detection loss suffered and the phase precision required for the carrier recovery for different error rates and with different degradations when BPSK and QPSK systems are used in the wireless channels. Generalized fading conditions including Rayleigh, Ricean, and Nakagami-m are taken into account.