Natalia Y. Ermolova

Moment Generating Functions of the Generalized η-μ and k-μ Distributions and Their Applications to Performance Evaluations of Communication Systems

In this letter, we prove that in contrast with earlier reported results the moment generating functions (MGFs) of the generalized eta - mu and re k - mu distributions are expressed in terms of elementary functions. Thus by employing the MGF-based approach one can easily evaluate average bit error rates (ABERs) in fading radio channels characterized statistically by the eta - mu and re k - mu distributions either in terms of elementary functions or in terms of finite-range integrals of elementary functions.

Useful integrals for performance evaluation of communication systems in generalised η - μand κ - μ fading channels

The author obtains closed-form expressions for the averages of the Gaussian Q-function and product of two Gaussian Q-functions over the generalised η−μ and κ−μ distributions. These results can be useful in many practical applications when evaluating error rate performances of communication systems operating in radio channels modelled by the η−μ and κ−μ distributions. The formulas are obtained in terms of Appells (F1(·) and Φ1(·)) and Lauricellas (FD3(·) and Φ1(3)(·)) hypergeometric functions. As examples of application, the average symbol error rates of general order rectangular quadrature amplitude modulation (QAM) in η−μ and κ−μ radio channels are evaluated.

Low complexity adaptive power and subcarrier allocation for OFDMA

The problem of low complexity sub-optimal power and subcarrier allocation for OFDMA systems is addressed in the paper. We propose a heuristic non-iterative method that is an extension of the ordered subcarrier selection algorithm recently proposed for a single user case to the OFDMA systems. The suggested method improves the average BER-performance of the system and it also provides fairness between the users in terms of the bit rates. Both the theoretical analysis and simulation results confirm efficiency of the proposed technique. Based on the proven lemma about inversion of power gains, we strengthen the suggested method by low complexity power loading that consists in equalization of the received signal-to-noise ratios of each user

On the relationship between peak factor of a multicarrier signal and aperiodic autocorrelation of the generating sequence

The well-known relationship between the peak-to-average power ratio (PAPR) of a multicarrier signal and the autocorrelation coefficients of the generating sequence is discussed. We emphasise that low values of the autocorrelation coefficients represent only a sufficient condition for a small value of the PAPR of the signal. Therefore, the autocorrelation coefficients of the generating sequences cannot serve as a basis for comparison of PAPR of the corresponding signals.

Channel capacity and average error rates in generalised-K fading channels

In the present study, the performance of digital communication systems operating over a composite fading channel modelled by the generalised-K distribution is analysed and evaluated. Novel closed-form expressions for the outage performance, the average bit error probabilities of several modulation schemes and the channel capacity under four different adaptive transmission schemes are derived. The analytical expressions are used to investigate the impact of different fading parameters of this composite fading channel model on the average bit error rate performance for a variety of digital modulation schemes and the spectral efficiency of different adaptive transmission policies.

The η-μ Fading Distribution with Integer Values of μ

In this paper, we analyze η-μ fading radio channels with integer values of the parameter μ. We obtain expressions for the probability density function and outage probability in terms of elementary functions. We also obtain novel closed-form expressions for the channel capacity under different adaptive transmission policies.

Spectral analysis of nonlinear amplifier based on the complex gain Taylor series expansion

A method of spectral analysis for a nonlinear amplifier driven by a Gaussian signal is presented. The technique is based on the Taylor series expansion of the complex gain of an amplifier. Therefore, it takes into account both amplitude-amplitude modulation (AM/AM) and amplitude-phase modulation (AM/PM) conversions and requires only an input signal autocorrelation (or power spectral density) and AM/AM and AM/PM measurements without any additional calculations.

On the Waveforms for 5G Mobile Broadband Communications

To realize the vision of ubiquitous mobile broadband where radio access performance should not be a limiting factor for user experience, we need to access very large bandwidths, and thus consider higher frequency bands up to the millimeter wave region. Air interface design, including waveforms, is a very important component for the success of 5G mobile broadband (MBB) in terms of flexibility, energy efficiency and cost efficiency. In this paper, we compare two waveforms, orthogonal frequency division multiplexing (OFDM) and filter bank multicarrier (FBMC), in terms of these requirements. We show that OFDM is a suitable waveform for MBB due to reasonably low overhead, low cost and latency; whereas FBMC loses its spectral properties when non-linear power amplifier is used.

Outage Probability Analysis in Generalized Fading Channels with Co-Channel Interference and Background Noise: η-μ/η-μ, η-μ/κ-μ, and κ-μ/η-μ Scenarios

In this paper, we present expressions for the cumulative distribution function (CDF) of a specially constructed random variable (RV) represented by the ratio of two generalized RVs. The obtained theoretical results are used to evaluate the outage probability in scenarios with η-μ-faded signals of interest (SoI), η-μ- or κ-μ-faded co-channel interference (CCI), and background white Gaussian noise. Our results are applicable also to scenarios where the SoI passes through the κ-μ fading channel, and the interfering signals are η-μ-faded. The derived results can be used if all parameters μ_i of the η-μ models representing the statistical distributions of either the SoI components or CCI components are integers. We prove, in particular, that in the former case, the CDF is expressed in terms of elementary functions.

Bivariate η-μ Fading Distribution with Application to Analysis of Diversity Systems

In this letter, we derive expressions for the moment generating function (MGF), for the probability density and cumulative distribution functions, as well as for joint moments of the bivariate η-μ fading distribution. By using the MGF-based approach, we obtain a finite-integral expression for evaluation of the bit error probability in dual-branch diversity systems with correlated branches. We present also an algorithm for generation of two correlated η-μ variables.