Equal Gain Combining Diversity Reception Research Articles

High-Order Statistics for the Channel Capacity of EGC Receivers Over Generalized Fading Channels

This letter presents novel results for the high-order capacity statistics of equal gain combining diversity receivers. The proposed methodology to obtain these results includes in the analysis the study of generalized fading channels and an arbitrary number of receiving antennas. Analytical expressions for the $n$ -th order capacity statistics as well as for the amount of dispersion, the reliability of the signal throughput, the kurtosis, and the skewness of the channel capacity distribution have been derived. The validity of the proposed methodology has been verified by means of Monte Carlo computer simulations. Furthermore, it has been shown that previously published results for the first-order capacity statistics are included in the analysis as special cases.

FSO communication with EGC diversity receiver over double generalised gamma turbulence channel

Recently, double generalised gamma (GG) distribution has been proposed as a generic model, to describe the irradiance fluctuations in free-space optical (FSO) communication systems. In this study, first the authors derive an approximate analytical expression for the distribution of the sum of independent but not necessarily identically distributed double GG random variables (RVs), considering the effects of the turbulence and pointing errors. Using well-known Beaulieu series, the authors describe the probability density function (pdf) and the cumulative distribution function (cdf) of the sum of double GG RVs in the form of a convergent series. The authors derive novel, exact closed-form expressions for the coefficients of the series in terms of the Meijer's G-function, which makes it possible to calculate the pdf and cdf of the sum of double GG variates under different turbulence conditions. In the next step, based on the presented results, the authors derive approximate analytical expression for the outage probability of the system and investigate the outage performance of the FSO link with equal-gain combining (EGC) receivers over double GG fading channels with pointing errors. Numerical results are further demonstrated to confirm the analytical results and also to show the good accuracy of the derived expressions.

Novel Tight Closed-Form Bounds for the Symbol Error Rate of EGC and MRC Diversity Receivers Employing Linear Modulations Over $$\alpha -\mu $$ α - μ Fading

In this paper, we propose novel lower and upper bounds on the average symbol error rate (SER) of the dual-branch maximal-ratio combining and equal-gain combining diversity receivers assuming independent branches. $$M$$ M -ary pulse amplitude modulation and $$M$$ M -ary phase shift keying schemes are employed and operation over the $$\alpha -\mu $$ ? - μ fading channel is assumed. The proposed bounds are given in closed form and are very simple to calculate as they are composed of a double finite summation of basic functions that are readily available in the commercial software packages. Furthermore, the proposed bounds are valid for any combination of the parameters $$\alpha $$ ? and $$\mu $$ μ as well as $$M$$ M . Numerical results presented show that the proposed bounds are very tight when compared to the exact SER obtained via performing the exact integrations numerically making them an attractive much simpler alternative for SER evaluation studies.

Some Notes on the Fourier Transform Methods for Error-Rate Analysis of Equal-Gain Combining

Transform techniques based on moment generating functions (MGFs) and characteristic functions (CHFs) have recently provided efficient analytical tools for the performance evaluation of digital communication systems over fading channels. More recently, the convolution theorem of the Fourier transform has been employed to obtain unified expressions for the average error probabilities of equal gain combining (EGC) diversity reception in terms of the CHFs of the branches' amplitude gains. In this paper, we prove that these expressions include redundant terms. Furthermore, simpler analytical expressions for the average error rates of EGC diversity reception can be obtained when the convolutional theorem of the sine and cosine transforms are used instead of the conventional Fourier transform.

Equal-gain combining diversity reception of M-ary cpsk signals in nakagami fading

An expression for the average symbol error rate of M-ary coherent phase-shift-keyed (CPSK) signals for equal-gain combining (EGC) diversity reception in slow Nakagami fading channels is derived using the characteristic function method. The new expression is presented in the form of a one-fold integral. This expression adapts readily for numerical computation of error rates with no restriction on the number of channels or the value of the fading severity index. Numerical results for the error rates are presented for 2- and 4-channel diversity reception of binary, quaternary and octonary CPSK signals.

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.

Error rates for Nakagami-m fading multichannel reception of binary and M-ary signals

This paper derives new closed-form formulas for the error probabilities of single and multichannel communications in Rayleigh and Nakagami-m (1960) fading. Closed-form solutions to three generic trigonometric integrals are presented as part of the main result, providing a unified method for the derivation of exact closed-form average symbol-error probability expressions for binary and M-ary signals with L independent channel diversity reception. Both selection-diversity and maximal-ratio combining (MRC) techniques are considered. The results are generally applicable for arbitrary two-dimensional signal constellations that have polygonal decision regions operating in a slow Nakagami-m fading environments with positive integer fading severity index. MRC with generically correlated fading is also considered. The new expressions are applicable in many cases of practical interest. The closed-form expressions derived for a single channel reception case can be extended to provide an approximation for the error rates of binary and M-ary signals that employ an equal-gain combining diversity receiver.

Derivation of Craig's formula for Gaussian probability function

A recent work provides two proofs for Craig's formula, which is an integral formula for the Gaussian probability density function. It also highlights the fact the original proof of the Craig formula is somewhat unclear. The authors of the work provide two proofs, one based on the Stieltjes transform of a Gaussian pulse and another based on the moment generation function (MGF) of a unit Gaussian random variable (GRV). Another integral formula for Q(x) based on the characteristic function (CHF) of a unit GRV is also provided. This formula can be applied to the analysis of coherent predetection equal-gain combining diversity receivers.

Performance analysis of optical receivers with space diversity reception

The performance of digital and analogue direct-detection optical receivers with space diversity reception is analysed. The cumulative probability distribution of the received signal is calculated for M-branch selection diversity and equal-gain combining diversity receivers. For a given probability of detection, the permissible threshold detection level is shown to increase with the number of diversity branches. The improvement in carrier-to-noise ratio (CNR) is shown to be higher for selection diversity compared to combining diversity detection. Optimum diversity array spacing is calculated; this shows the practicality of space diversity systems.