Nagendra Kumar

Performance Analysis of Amplify-and-Forward Cooperative Networks with Best-Relay Selection Over Weibull Fading Channels

We analyze and study the performance of amplify-and-forward cooperative diversity communication network with best-relay selection over Weibull fading channel. In this paper, a closed-form expression for the moment generating function (MGF) of the total signal-to-noise ratio at the destination is derived in terms of the tabulated Meijer’s G-function. By the help of this derived MGF expression, we analyze the average symbol error rate (ASER) and outage probability over independent and identical distributed Weibull fading channels for multiple relays. The numerical values of ASER and outage probability expressions are compared with Monte-Carlo simulation result to verify the accuracy of the derivation.

Performance analysis of OFDM based AF cooperative systems in selection combining receiver over Nakagami-m fading channels with nonlinear power amplifier

In this paper, we investigate the performance of orthogonal frequency division multiplexing (OFDM) based amplify-and-forward (AF) cooperative relaying systems over independent and identically distributed (i.i.d) Nakagami-m fading channels. Specifically, we derive a closed-form expression for lower bound of outage probability by using selection combining (SC) scheme at the receiver. A nonlinear power amplifier (PA) is considered at the relay which introduces the nonlinear distortions. We present simulation and numerical results to validate the theoretical analysis, and demonstrates the impact of nonlinearity of PA parameters over outage probability for different values of threshold signal-to-noise ratio (SNR) at various mean SNR levels

Outage Analysis of OFDM Based AF Cooperative Systems in Selection Combining Receiver over Nakagami-m Fading Channels with Nonlinear Power Amplifier

In this paper, we investigate the performance of orthogonal frequency division multiplexing (OFDM) based amplify-and-forward (AF) cooperative relaying systems over independent and identically distributed (i.i.d) Nakagami-

Mitigating NLD for Wireless Networks: Effect of Nonlinear Power Amplifiers on Future Wireless Communication Networks

m

Exact ASER Analysis of Rectangular QAM in Two-Way Relaying Networks Over Nakagami-

fading channels. Specifically, we derive a closed-form expression for lower bound of outage probability by using selection combining (SC) scheme at the receiver. A nonlinear power amplifier (PA) is considered at the relay which introduces the nonlinear distortions. We present simulation and numerical results to validate the theoretical analysis, and demonstrates the impact of nonlinearity of PA parameters over outage probability for different values of threshold signal-to-noise ratio (SNR) at various mean SNR levels

m

Efficient utilization of limited bandwidth with high-data-rate transmission while serving a large number of users is a prime requirement for present and future wireless communication systems. To meet this rising demand, orthogonal frequency-division multiplexing (OFDM) and cooperative communication have emerged as promising solutions due to their robustness in severely degraded channel conditions, link reliability, and spectral efficiency. Both OFDM and cooperative systems have challenged RF front-end specifications such as bandwidth and power-efficiency requirements for end users as well as for the base station due to the high peak-to-average power ratio (PAPR). In present and future communication systems, the power amplifier (PA) is a key component at the transmitter. To obtain maximum power efficiency, the PA is operated near its saturation point, which leads to nonlinear distortion (NLD), which is further exaggerated due to the high PAPR of the input signal. This NLD is expected to increase in future fifth-generation (5G) communication networks, due to the use of large bandwidth at millimeter-wave (mmW) frequencies.

Fading Channels

In this letter, we derive an exact closed-form expression for average symbol error rate (ASER) of general order rectangular quadrature amplitude modulation (RQAM) scheme in two-way amplify-and-forward relaying network by using cumulative distribution function-based approach over independent and non-identically distributed Nakagami-m fading channels with integer values of fading parameter. Furthermore, we investigate exact closed-form expressions of ASER for 32-cross QAM, differentially encoded quadri-phase shift-keying (DE-QPSK) and π/4-QPSK modulation schemes. The asymptotic expression of ASER for RQAM scheme, in high signal-to-noise ratio regime, is also proposed to examine a useful insight into system diversity order. Furthermore, Monte Carlo simulations are performed to compare the numerically evaluated results and verify accuracy of the derived expressions.

Outage analysis of OFDM AF relaying systems over Nakagami-m fading channels with non-linear power amplifier

This paper presents analysis of outage probability of an amplify-and-forward (AF) orthogonal frequency division multiplexing (OFDM) based relay network with maximal ratio combining (MRC) technique at the receiver. In this paper, a closed-form expression for a tight lower-bound of outage probability is derived under the frequency selective Nakagami-m fading channels, where m is an integer. A non-linear power amplifier (PA) is considered at the relay node which introduces the non-linear distortion. This analysis describes the effect of non-linear PA parameters over outage probability at various signal-to-noise ratio (SNR) levels. The numerical values of outage probability expression is compared with computer simulations to verify the accuracy of the derivation.

Outage Probability and Average Channel Capacity of Amplify-and-Forward in Conventional Cooperative Communication Networks over Rayleigh Fading Channels

Performance of conventional cooperative communication networks using amplify-and-forward relay over independent and identically distributed Rayleigh fading channels is investigated in this paper. An expression for probability density function by using moment generating function is obtained. Further closed-form expressions of the outage probability and the average channel capacity are derived. The derived analytical results are compared with Monte Carlo simulations to confirm correctness of the derived expressions.

Performance analysis of orthogonal frequency division multiplexing-based cooperative amplify-and-forward networks with non-linear power amplifier over independently but not necessarily identically distributed Nakagami-m fading channels

In this study, performance analysis of variable-gain amplify-and-forward relaying orthogonal frequency division multiplexing-based systems over independently but not necessarily identically distributed Nakagami-m fading channels using non-linear power amplifier (PA) at the relay and maximal ratio combining scheme at destination. Specifically, novel closed-form expressions of outage probability and asymptotic outage probability are investigated for the considered system model. Further, an average symbol error rate (ASER) expression is derived for general-order rectangular quadrature amplitude modulation (RQAM) scheme using cumulative distribution function-based approach, which is also the novel contribution of the work. Since the transfer function of PA used at relay is nonlinear, this introduces non-linear distortion (NLD) in the considered system model. Thus, the impact of NLD and fading parameters on outage probability, diversity gain of the system and ASER performances are analysed. Further, the impact of NLD on constellation order for RQAM scheme is also discussed. The theoretical results are compared with computer simulations to verify the accuracy of the derivations. The derived expressions are generalised over variety of fading environments for integer-valued fading parameter.