Two-wave With Diffuse Power Fading Channels Research Articles

On the Exact Closed-Form ABEP Analysis of Downlink NOMA Over mmWave TWDP Fading

This paper presents the performance analysis of two users’ downlink non-orthogonal multiple access (NOMA) over a millimeter-wave two-wave with diffuse power (TWDP) fading model for successive interference cancellation errors. The new closed-form expressions of average bit error probability (ABEP) for both users are derived for quadrature phase-shift-keying and binary phase-shift-keying modulation pairs. Further, the asymptotic ABEP expressions are derived to provide better insights into the performance analysis. The diversity order of each user is also derived with the aid of asymptotic ABEP expression. The obtained expressions over TWDP fading channels are generalized ABEP expressions as it also shows ABEP expressions for both Rician and Rayleigh fading channels as special cases. Simulation results support the correctness of each analytical ABEP expression.

Spectrally efficient M‐ary QAM based multi‐antenna cooperative system over TWDP fading channel

AbstractTo cater the ever‐increasing demand of wireless high‐speed data access and mobile users, one of the potential enablers toward the sustainable improved network capacity is the network densification at different layers of the radio access system. In this article, a possible solution to achieve a spectrally efficient, ultradense network (UDN) for cellular communication is analyzed. In particular, the performance of the generalized M‐ary quadrature amplitude modulation (M‐QAM) scheme for multiantenna cooperative decode‐and‐forward (DF) system over two‐wave with diffuse power (TWDP) fading is presented. The TWDP fading is evaluated using the moment generating function (MGF) based approach on spectral efficient QAM transmission. In this article, novel closed‐form expressions for the exact average symbol error rate (ASER) for the generalized rectangular‐QAM (R‐QAM) and square‐QAM (S‐QAM) schemes are presented. The obtained expressions are in the form of Appell's and Laureicella's confluent hypergeometric function which can be evaluated mathematically either in the series or the integral‐form. Further, the asymptotic analysis is also presented for the considered system to get better insights into the system. The analytical results derived are corroborated by simulations to validate the accuracy of the analysis.

Reliable Multi-Point Transmissions Over Directional MISO TWDP Fading Channels

In this paper, we consider wireless transmissions over directional multiple-input single-output (MISO) two wave with diffuse power (TWDP) fading channels, subject to interference over the same type of channel. TWDP fading is known to exhibit an outage behavior that can be even worse than Rayleigh fading and has experimentally been observed in a number of vehicular channel measurement campaigns. To enhance the reliability of multi-point transmissions over MISO TWDP fading channels, we propose a zero-forcing based coordinated beamforming scheme, for which we can analytically characterize and optimize the outage probability of the multi-point transmissions. Based on the developed outage expressions, we furthermore propose a greedy coordinated scheduling approach that attempts to maximize the achievable rate of the system. Finally, we propose a transmission rate adaptation scheme for fixed size packet transmissions, which supports reliable and at the same time resource efficient multi-point transmissions.

Symbol Error Rate Analysis of OFDM System with CFO Over TWDP Fading Channel

In this manuscript, an exact symbol error rate analysis of orthogonal frequency division multiplexing system is presented in the presence of carrier frequency offset over two wave with diffuse power (TWDP) fading channel. Both Binary Phase Shift Keying and Quadrature Phase Shift Keying modulation techniques are considered in this study over TWDP channel which contains Rayleigh, Rician and two ray fading as its special cases. The results are validated by means of Monte Carlo simulations and also verified from the benchmark results available in the literature.

Performance Analysis of Nonlinear SFBC OFDM Systems Over TWDP Fading Channel

In this paper, the practical performance of space-frequency block code (SFBC)-based multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system in the presence of nonlinear power amplifier with imperfect channel state information (CSI) over two-wave with diffuse power (TWDP) channel is analyzed. In the performance analysis, we first introduce the equivalent single-input single-output (SISO) scalar model with nonlinear power amplifier and then the SISO model is used to construct a model for the nonlinear MIMO-OFDM system. Considering the channel estimation error at the receiver, we study the effects of MMSE channel estimation error on the channel capacity. What is more, based on inter modulation product (IMP) analysis, we study the BER performance of nonlinear SFBC MIMO-OFDM systems, considering M-ary phase shift keying (MPSK) and M-ary quadrature amplitude modulation (MQAM). And the effects of channel estimation error on the BER performance are studied. Finally, this paper also derives the closed-form expressions of the system optimal operating point. The numerical results and comparisons are provided for several forms of SFBC MIMO-OFDM. From these analysis results, it is found that the analytical interpretation of the observed behavior in the simulation can be advanced, and the actual analysis of the performance optimization of the nonlinear MIMO-OFDM system is also provided.

Generalized MGF of the Two-Wave With Diffuse Power Fading Model With Applications

We provide new analytical results for the two-wave with diffuse power (TWDP) fading model. Specifically, we derive a closed-form expression for its generalized moment generating function in terms of a finite number of standard hypergeometric functions. This result is used to compute the moments of the TWDP distribution, as well as to analyze the performance of wireless communication systems operating under TWDP fading channels in the context of energy detection, error and outage performances, and physical layer security.

Performance analysis of spectrum sensing techniques over TWDP fading channels for CR based IoTs

In this paper, the performance of spectrum sensing techniques over two wave diffused power (TWDP) fading channels has been investigated for CR based IoT devices. The ubiquitous objects based on IoTs with cognitive capabilities are the future that would enable intelligent decisions to achieve any time, any place, interference-free and on-demand services. In this work, new closed-form expressions in terms of Marcum-Q function and Whittaker function for the spectrum detection probability over TWDP fading channels have been derived for different sensing techniques. The expressions are then used to optimize the decision threshold for IoT sensor nodes describing the optimal behavior of sensing over TWDP channels. The error probabability and Receiver Operating Characteristic (ROC) curves have been plotted and the operating point and limiting values of threshold for optimal performance have been identified. The performance loss of traditional energy detection (ED), cyclostationary based detection (CSD) and matched filtering detector (MFD) has been analyzed. The analytical results thus obtained are validated through monte-carlo simulations.

Performance of M ‐EGC receiver over TWDP fading channels

This study gives a general bit-error rate expression, using Gil-Palaez lemma-based approach, of a M branch equal gain combining (EGC) receiver over two-wave diffused power (TWDP) fading channels. The expressions obtained are evaluated numerically and the results are verified using Monte Carlo simulation. Also the impact of the fading parameters δ and K on the performance of M branch-EGC has been analysed.

BER Performance of SFBC OFDM System Over TWDP Fading Channel

In this letter, the performance of uncoded and space frequency block coding (SFBC) orthogonal frequency division multiplexing (OFDM) system over two-wave with diffuse power (TWDP) fading environment is analyzed. A general closed-form expressions of average bit error rate for both $M$ -ary phase shift keying and $M$ -ary quadrature amplitude modulation are derived using moment generating function of TWDP fading distribution. Results are verified with the benchmark results available in the literature (i.e., Rayleigh and Rician). Numerical results with various TWDP fading channel parameter ( $K$ and $\Delta $ ) and with different modulation orders for uncoded and SFBC OFDM systems show excellent agreement with simulation results.

Performance Analysis of a Low-Complexity Detector for MCIK-OFDM Over TWDP Fading

This letter analyzes the performance of a low-complexity detection scheme for a multi-carrier index keying (MCIK) with orthogonal frequency division multiplexing (OFDM) system over two-wave with diffuse power (TWDP) fading channels. A closed-form expression for the average pairwise error probability over TWDP fading channels is derived. This expression is used to analyze the performance of MCIK-OFDM in moderate, severe, and extreme fading conditions. The presented results provide an insight on the performance of MCIK-OFDM for wireless communication systems that operate in enclosed metallic structures, such as in-vehicular device-to-device wireless networks.

Analysis of Hybrid Diversity Combining Technique over TWDP Fading Channel

Background/Objectives: Tremendous growth in the mobile communication services in this technology driven era has made possible for the people to exchange information (data, voice or image) with each other while they are on the move. These wireless systems have brought a revolution in the current market for their high data rates and performance enhanced features. Methods/Statistical Analysis: One of the key issues affecting the performance of a wireless channel is the random variations in the signal strength which may be resulted due to some obstructions like buildings, trees, etc. or due to the movement of the mobile user. This leads to stochastic behavior of the radio channel.. A highly faded Two-Wave with Diffuse Power (TWDP) environment is discussed along with hybrid diversity combining technique. The effectiveness of this scheme is further evaluated by analyzing the system performance in terms of Bit Error Rate (BER) vs Signal to Noise Ratio (SNR). Binary Phase Shift Keying (BPSK) and Quadrature Phase Shift Keying (QPSK) modulation techniques were employed. Findings: It has been shown clearly that TWDP forms the poorer link when compared with other fading channels as BER is higher in this case. Moreover, TWDP fading environment can serve as the worst case scenario in wireless communication system. Also it has been shown as the diversity order increases system’s performance is improved in terms of BER and reduction in SNR requirement to achieve a constant BER value. Application/Improvement: This paper presents the need to obtain a clear perception of channel characteristics and to model a system for combating fading and improving the system performance by considering a TWDP fading channel instead of Rayleigh channel while designing a wireless communication system in worst channel conditions..

Performance of M-ary PSK over TWDP fading channels

ABSTRACTPerformance of M-ary phase shift keying (MPSK) is analysed in two-wave with diffuse power (TWDP) fading channel. The TWDP channel is characterised by two specular waves along with the diffuse power and has both Rayleigh and Rician fading distributions as special cases. Closed-form expression for the bit error rate (BER) of MPSK (M > 4) in TWDP fading is derived using Chiani approximation for the complimentary error function. Numerical results show excellent agreement with the simulation results.

Performance of SC Receiver over TWDP Fading Channels

Performance of selection combining (SC) receiver has been derived over two-wave diffused power (TWDP) fading channels with arbitrary and non-identical fading parameters. An expression of cumulative distribution function (CDF) of signal-to-noise ratio (SNR) for TWDP fading channel has been derived, which is used to obtain the probability density function (PDF) of SNR at the output of SC receiver. The PDF of output SNR has been used to derive expressions of outage probability and average bit error rate for coherent and non-coherent modulation schemes. Effect of total number of branches M and the fading parameters K and Δ on the system performance has been studied. The obtained results are verified with the special case results available in literature and by Monte Carlo simulation.

Performance of QAM Signaling over TWDP Fading Channels

Performance of quadrature amplitude modulation (QAM) scheme in two-wave with diffuse power (TWDP) fading environment is analyzed. Closed-form expressions for the exact average symbol error rate (ASER) of general order rectangular QAM (RQAM) and cross QAM (XQAM) schemes are presented using moment generating function of TWDP fading distribution. Obtained ASER expressions are in the form of Appell's (Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> (·)) and Lauricella's (Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(3)</sup> (·)) hypergeometric functions which can be numerically evaluated using either integral or series representation. Further, closed-form expression for the nth order moment of the received signal-to-noise ratio is derived. Numerical results show excellent agreement with simulation results.