Analysis of Equal Gain Diversity Receivers in Correlated Rayleigh Fading Channels
Dept. of Electr. & Comput. Eng., Virginia Polytech. Inst. & State Univ., USA IEEE Communications Letters
(Impact Factor: 1.27).
07/2004; 8(6):362 - 364. DOI: 10.1109/LCOMM.2004.828225
Utilizing a desirable exponential integral representation of Gaussian probability integral, this letter derives the average bit error rate (ABER) expressions for coherent binary signals that employ a dual branch equal gain combining receiver. Our numerical results reveal that the branch correlations do not affect the ABER significantly provided power correlation coefficient is less than 0.3 in Rayleigh fading.
Available from: Adeel Razi
- "Once the closed form formulae of the moments of SNR are obtained, we can use the momentsbased approach to compute the approximate performance of the relay system. However, to get expressions for the ABEP and P out , we employ the CHF method as in   . The main contributions of this paper include the following: (a) derivation of closed form formulae for the moments of the overall SNR, (b) derivation of the CHF of the fading envelope, which can be expressed in product and polar forms, (c) derivation of the analytical expressions for the ABEP for coherent and noncoherent schemes, and (d) evaluation of the outage probability of the system in terms of one integral, which can be computed easily. "
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ABSTRACT: The end-to-end performance of multibranch dual-hop wireless communication systems with nonregenerative relays and equal gain combiner (EGC) at the destination over independent Nakagami-m fading channels is studied. We present new closed form expressions for probability distribution function (PDF) and cumulative distribution function (CDF) of end-to-end signal to noise ratio (SNR) per branch in terms of Meijer's G function. From these results, analytical formulae for the moments of the output SNR, the average overall SNR, the amount of fading, and the spectral efficiency are also obtained in closed form. Instead of using moments-based approach to analyze the asymptotic error performance of the system, we employ the characteristic function (CHF) method to calculate the average bit error probability (ABEP) and the outage probability for several coherent and noncoherent modulation schemes. The accuracy of the analytical formulae is verified by various numerical results and simulations.
Available from: scholar.lib.vt.edu
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ABSTRACT: Diversity combining schemes are successfully applied in communication systems. In many recent publications the performance of different diversity combining schemes in different fading scenarios and with different modulation schemes was analyzed and analytical expressions for the performance derived. It turned out that the performance depends on the statistics of the fading, especially on the correlation of the diversity branches. In this work, we study the impact of correlation on the performance of the maximum ratio, equal gain, and selection combining schemes without computing directly the error rate. The performance depends only on the eigenvalues, i.e. powers, of the correlation matrix and not on the eigenvectors. Therefore, majorization theory can be used as a measure of the correlation. We show that the performance of maximum ratio combining and equal gain combining are Schur-convex functions with respect to the correlation eigenvalues, i.e. correlation increases the error rate. Surprisingly, the behavior of selection combining depends on the SNR: for small SNR, correlation decreases the error rate, whereas for high SNR, correlation increases the error rate. Finally, we illustrate the theoretical results by numerical simulations.
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