Output Of Maximal Ratio Combiner Research Articles

On effective rate and energy detection based spectrum sensing over cascaded FTR fading channel

The detrimental effects of multipath fading and multi-hope/keyhole propagation of millimetre–wave (mm) on the effective rate (ER) and the detection performance of energy detector (ED) have been investigated in this article. Cascaded fluctuating two ray fading model have been used to characterize the mm-wave propagation environment. Utilizing probability density function-based approach, novel closed form mathematical expressions for ER, average detection probability (ADP) and average area under the receiver operating characteristics (AUC) for the single and multi-antennae receiver-based system have been derived. To this end, novel mathematical expression for instantaneous signal to noise ratio (SNR) at the output of maximal ratio combiner (MRC) is also obtained. Subsequently obtained results are employed to compute performance metrics for the collaborative spectrum sensing where each individual receiver consists of multiple antennae. Obtained expressions are useful to evaluate ER and ED performance over different fading scenarios impaired due to cascading effects, and also helps to maintain ER versus ADP trade-off by exploiting time-bandwidth product relation. Analysis shows a considerable degradation in ER and ADP as the channel cascading effect increases and employing diversity reception is useful to overcome the degraded performance. In the end, Monte-Carlo simulations are provided to validate the numerical accuracy of theoretically derived expressions.

Multivariate Correlated Rayleigh Fading With MRC and Applications to Wireless Secrecy

This letter studies physical layer security of an outdated channel-state-information (oCSI) decode-and-forward (DaF) opportunistic-relay (OR) network under equal-correlated (equ.c.) Rayleigh fading with maximal ratio combining (MRC) deployment. By assuming that relays operate under equ.c. Rayleigh fading and wiretapper-Destination operate under exponential-correlated (exp.c.) Rayleigh fading, this work (i) derives an MRC output (MRCO) distribution of multivariate equ.c. Rayleigh fading, (ii) derives an MRCO distribution of bivariate exp.c. Rayleigh fading under oCSI conditions, and (iii) expresses the secrecy outage probability (SOP) in closed form. By considering oCSI severity, channel correlation among cooperative DaF ORs, Destination, wiretapper, and MRC deployment, this work's practicality can be significantly improved. Detailed discussions are given, in which the impact of several important parameters on the SOP is discussed. Monte Carlo simulation is shown to match theoretical predictions.

Complete solutions for the outage probability of maximal ratio combining diversity on Nakagami‐ m fading channels with unequal power branches valid for integer m

Maximal ratio combining (MRC) diversity is fundamental in wireless communication theory and widely implemented in practice. There are limited results in the theory for the probability density function (PDF) of MRC diversity on Nakagami channels when the branches have unequal powers. In addition to being restricted, the known solutions are complex and in some cases unwieldy. Novel, complete solutions for the PDF of MRC signal-to-noise ratio (SNR), valid for integer values of the Nakagami fading parameter m and arbitrary branch powers, are derived. In addition to being solutions for the unsolved cases, the new solutions give different and much simpler expressions for the known restricted cases than previous solutions. The effects of branch channel power imbalances on the PDF of MRC and on the outage probability are investigated quantitatively. The new solutions are used to derive asymptotic large SNR performance measures for MRC diversity with unequal branch powers, insights not obtainable from previous solutions. The new solutions are used to derive intuitive simple approximations for the densities and distributions of MRC output signal power and amplitude, as well as for the outage probability. The approximations are shown to have excellent accuracies for power imbalances <;30% and good accuracies for power imbalances <;60%.

Performance Analysis of the MRC M2M System

The average symbol error probability (ASEP) of a mobile-to-mobile (M2M) system employing maximal ratio combining (MRC) over N-Nakagami fading channels is investigated in this paper. The characteristic function (CF) of the signal-to-noise ratio (SNR) at the MRC output is used to derive exact ASEP expressions for several q-ary modulation schemes, including phase shift keying (PSK) modulation, quadrature amplitude modulation (QAM), and pulse amplitude modulation (PAM). Then the ASEP performance under different channel conditions is evaluated through numerical simulation to verify the analysis. These results show that the performance of the MRC M2M system is improved as the number of diversity branches or the fading coefficient is increased. Conversely, performance is degraded as the number of cascaded components is increased.

MRC Dual-Diversity System over Correlated and Non-Identical Ricean Fading Channels

Motivated by the importance of the Ricean statistical model in describing communication channels, in this paper we study the performance of a dual-branch receive diversity system operating in Ricean fading. Maximal ratio combining (MRC) of two correlated and non-identical Ricean fading channels is considered. A novel mathematical approach for the performance evaluation of the analyzed system is presented. The probability density and cumulative distribution functions of the total received signal-to-noise ratio at the MRC output are derived in a form of rapidly converging infinite sum. Based on the derived expressions, we further proceed with the calculation of the outage probability and the average bit error rate performance of the diversity system under study. The obtained analytical results are verified through an appropriate simulation model.

On the Performance of the Layered-Division-Multiplexing using Maximal-Ratio Combining

This article proposes the diversity gain enhancement in layered division multiplexing (LDM) systems by applying maximal-ratio combining (MRC) technique. LDM systems is adopted as a baseline technology of the ATSC 3.0 systems which the two transmission layers are simultaneously transmitted over two different types of fading channels for fixed and mobile services. Hence, the performance analysis of each layer need to be evaluated on different type of fading channel. Starting with the moment generating function (MGF) of the MRC output signal-to-noise ratio (SNR), we propose the new method to derive closed-form expressions for average symbol-error rate (SER) of the proposed systems over Rayleigh and Nakagami-m fading channels in the presence of error propagation (EP) that is generated from the first layer detection. Analytical results show that the specific value of injection level at the transmitter need to be precisely defined to obtain the best mutual benefit for both LDM layers, and the proposed technique has significant performance advantage over conventional LDM systems. Simulation results demonstrate the tightness of the author’s analysis.

Maximal ratio combining in independent identically distributed N*Nakagami fading channels

Short-term fading in wireless systems can be described using a cascaded approach permitting the modelling of severely faded channels. A maximal ratio combining (MRC) diversity is implemented to study the performance improvement in such channels. While the probability density function (pdf) of the signal-to-noise ratio of the independent and identically distributed N*Nakagami cascade channels is available in terms of Meijer's G functions, the pdf of the MRC output is not available. Because of this, the moment generating function of the MRC output is used to estimate the average bit error rates. The characteristic function is used to obtain the cumulative distribution (CDF) of the MRC output by applying the Gil-Pelaez approximation. The outage probabilities were then estimated using the CDF. Results showed that the wireless system performance improved with diversity even though the level of improvement declined as the number of cascaded components N increased. The analysis also suggests that additional mitigation such as combining signals from multiple base stations (macrodiversity) might be necessary to significantly improve the performances of cascaded channels.

BEP/SEP and Outage Performance Analysis of -Branch Maximal-Ratio Combiner for Fading

Maximal-ratio combiner (MRC) performances in fading channels have been of interest for a long time, which can be seen by a number of papers concerning this topic. In this paper we treat bit error probability (BEP), symbol error probability (SEP) and outage probability of MRC in presence of fading. We will present fading model, probability density function (PDF), and cumulative distribution function (CDF). We will also present PDF, CDF, and outage probability of theL-branch MRC output. BEP/SEP will be evaluated for broad class of modulation types and for coherent and noncoherent types of detection. BEP/SEP and outage performances of the MRC will be evaluated for different number of branches via Monte Carlo simulations and theoretical expressions.