Diffuse Power Fading Research Articles

Closed‐form expression of long‐range modulated massive multiple‐input multiple‐output fractional Fourier transform‐orthogonal frequency division multiplexing system under two‐wave with diffuse power fading channel

SummaryIn this paper, the massive multiple‐input multiple‐output fractional Fourier transform‐based orthogonal frequency division multiplexing (MIMO FrFT‐OFDM) system is investigated using the Long Range (LoRa) modulation technique. The conventional system relies on quadrature amplitude modulated (QAM) modulation technology; high‐power amplifiers are needed to transmit the QAM signal. The LoRa modulation technique produces long‐range and low power signals. The two‐wave with diffused power (TWDP) fading channel is used to examine the system's performance. The expression of the bit‐error rate (BER) of the proposed system is also represented in a unique closed form. The proposed system is applied to a state‐of‐the art hospital, one of the Internet of Things (IoT) applications. As the problem of heart stroke is common, it needs to be monitored every second. The electrocardiogram (ECG) data are used to evaluate how well the proposed system is working. Using the proposed model, the physicians get the patient's ECG data while moving in the hospital, getting it at a high data rate, at a low cost because of the extended battery life, a long range, and a low BER. The data considered are from the MIT‐BIH Arrhythmia Database. The result displays that the proposed model achieves a BER of at 10 dB of signal‐to‐noise ratio (SNR), and the conventional model achieves the same BER at 15 dB of SNR. The BER performance of the proposed system is improved by nearly 5 dB.

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.

Performance Evaluation of DCSS using Two Level 1-Bit Hard Decision Strategies over TWDP Fading Channel

The spectrum sensing method's dependability is greatly influenced by two of the most crucial factors, including various fading channels and nearby wireless users. Multipath fading, buried terminals, and shadowing are just a few of the challenges encountered by users of non-cooperative spectrum sensing systems. Cooperative spectrum sensing approach gives a remedy for this issue. With the use of the common receiver, CSS permits the user to detect the spectrum. Additionally, it has been separated into distributed CSS (D-CSS) and centralized CSS (C-CSS). By using particular rules to identify the presence of the licensed user, both concepts are compared to one another in this article. The effectiveness of cluster-based distributed cooperative spectrum sensing over two-wave diffuse power fading channels (TWDP Channel) is also examined in the article. Wei-bull and Hoyt fading channels are two examples of fading channels that have previously exploited this idea. In this paper, simulation findings for the less well-known two-wave with diffuse power channels are reviewed. This work mainly focused on CSS over TWDP fading channels along with several proposed approach for two stage hard decision strategies using AND fusion and OR fusion. The simulation performance findings for TWDP fading situation enhance the OR_AND fusion strategy detection performance at various SNR levels. The presented D-CSS approach helps users to get beyond the difficulty they have when using non-cooperative spectrum sensing and lists the relationship among detection efficiency and power consumption for Cognitive radio technology used in constrained wireless environments.

Performance analysis of non‐orthogonal multiple access assisted cooperative maritime communication system over two‐wave with diffuse power fading

AbstractNon‐orthogonal multiple access (NOMA) and millimeter‐wave (mmWave) communication are two promising technologies to fulfill the high throughput and reliable communication requirements. Maritime communication systems use a generalized fading at near‐sea‐surface channels (for seashore to ship/boat/fishing fleet communication) to provide reliable communication due to atmospheric turbulence. Experimental research on generalized two‐wave diffuse power (TWDP) fading reveal the footprints of mmWave. This article proposes novel exact and asymptotic closed‐form expressions of average symbol error probability (ASEP) of NOMA users for cooperative maritime communication systems over TWDP fading with the different modulations. The end‐to‐end closed‐form expressions are derived in terms of Appell's and Lauricella's hypergeometric functions. Also, the ASEP is shown using the power allocation factor for different modulation schemes. The proposed system provides better transmission reliability using generalized TWDP fading. Further, the outage probability of the system described above is analyzed using the distance, path loss exponent, transmission rate, and Rician factor as performance metrics for both the NOMA users. Effects of fading outage parameters on the system performance are studied. The end‐to‐end exact numerical results have been verified with the Monte‐Carlo simulations that validate with asymptotic results at a high SNR regime.

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.

Hypergeometric Functions of Several Variables and Evaluation of Error Probability in Fading Multichannel System

A method is proposed of evaluation of symbol and/or bit error probabilities for coherent diversity receiving of multipositional signal constructions in communication channel with fadings, which are described with the help of classical and generalized models Multiple-Wave with Diffuse Power (MWDP) fading and of additive white Gaussian noise (AWGN). This method uses the hypergeometric functions of several variables.

Application of Hypergeometric Functions of Several Variables in the Mathematical Theory of Communication: Evaluation of Error Probability in Fading Singlechannel System

A method is proposed of evaluation of symbol and/or bit error probabilities for coherent receiving of multipositional signal constructions in communication channel with fadings, which are described with the help of classical and generalized models Multiple-Wave with Diffuse Power (MWDP) fading and of additive white Gaussian noise (AWGN). This method uses the hypergeometric functions of several variables.

Performance Analysis of QAM over One Wave Diffused Power Fading Channels

In wireless channels the capacity degrades due to fading. In this paper analysis of the Quadrature Amplitude Modulation (QAM) on One Wave Diffused Power (OWDP) fading channels have computed. A general expression for the RQAM is expressed for this channel. The calculated expressions have been evaluated by using the method of probability density function of OWDP fading. The Average Symbol Error Rate for RQAM scheme has been derived in the form confluent Hypergeometric function. The results are simulated and matched with Monte Carlo simulations.

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.

A Novel Weighted-Counter Method for Simulating Coherent TWDP Fading Channels

New channel simulation models are needed for the study of future wireless networks, 5G and beyond. A novel simulation technique dubbed weighted-counting is proposed. It is used to generate random variates having the two-wave with diffuse power (TWDP) fading amplitude distribution. The TWDP channel model describes high-speed train, femtocell, sea surface, heterogeneous, and other channels having two different dominant line-of-sight waves as well as scatter power components.

Better than Rician: modelling millimetre wave channels as two-wave with diffuse power

This contribution provides experimental evidence for the two-wave with diffuse power (TWDP) fading model. We have conducted two indoor millimetre wave measurement campaigns with directive horn antennas at both link ends. One horn antenna is mounted in a corner of our laboratory, while the other is steerable and scans azimuth and elevation. Our first measurement campaign is based on scalar network analysis with 7 GHz of bandwidth. Our second measurement campaign obtains magnitude and phase information; it is additionally sampled directionally at several positions in space. We apply Akaike’s information criterion to decide whether Rician fading sufficiently explains the data or the generalised TWDP fading model is necessary. Our results indicate that the TWDP fading hypothesis is favoured over Rician fading in situations where the steerable antenna is pointing towards reflecting objects or is slightly misaligned at line-of-sight. We demonstrate TWDP fading in several different domains, namely, frequency, space, and time.

Adaptive M-MRC scheme with estimation error over TWDP fading

High speed data requirement among a large group of user is one of the key challenges in wireless communication. To meet this requirement adaptive multi-antenna system (adaptive diversity receiver) is a well known potential solution in wireless system design. Nevertheless, the ideal estimation technique which is considered to optimise the performance of a diversity receiver is difficult to get. Hence, in a practical scenario, the expected system performance of the receiver is considerably degraded. In this paper the average bit error rate (ABER) and capacity analysis has been studied for an arbitrary branch maximum ratio combiner (MRC) system for different modulation techniques over two wave diffused power (TWDP) fading channels with error in estimation.

Adaptive M-MRC scheme with estimation error over TWDP fading

High speed data requirement among a large group of user is one of the key challenges in wireless communication. To meet this requirement adaptive multi-antenna system (adaptive diversity receiver) is a well known potential solution in wireless system design. Nevertheless, the ideal estimation technique which is considered to optimise the performance of a diversity receiver is difficult to get. Hence, in a practical scenario, the expected system performance of the receiver is considerably degraded. In this paper the average bit error rate (ABER) and capacity analysis has been studied for an arbitrary branch maximum ratio combiner (MRC) system for different modulation techniques over two wave diffused power (TWDP) fading channels with error in estimation.

Position-Specific Statistics of 60 GHz Vehicular Channels During Overtaking

The time-variant vehicle-to-vehicle radio propagation channel in the frequency band from 59.75 to 60.25 GHz has been measured in an urban street in the city center of Vienna, Austria. We have measured a set of 30 vehicle-to-vehicle channel realizations to capture the effect of an overtaking vehicle. Our experiment was designed for characterizing the large-scale fading and the small-scale fading depending on the overtaking vehicle’s position. We demonstrate that large overtaking vehicles boost the mean receive power by up to 10 dB. The analysis of the small-scale fading reveals that the two-wave with diffuse power (TWDP) fading model is adequate. By means of the model selection, we demonstrate the regions where the TWDP model is more favorable than the customarily used the Rician fading model. Furthermore, we analyze the time selectivity of our vehicular channel. To precisely define the Doppler and delay resolutions, a multitaper spectral estimator with discrete prolate spheroidal windows is used. The delay and Doppler profiles are inferred from the estimated local scattering function. Spatial filtering by the transmitting horn antenna decreases the delay and Doppler spread values. We observe that the RMS Doppler spread is below one-tenth of the maximum Doppler shift 2f v/c. For example, at 60 GHz, a relative speed of 30 km/h yields a maximum Doppler shift of approximately 3300 Hz. The maximum RMS Doppler spread of all observed vehicles is 450 Hz; the largest observed RMS delay spread is 4 ns.

Unveiling the Hyper-Rayleigh Regime of the Fluctuating Two-Ray Fading Model

The recently proposed Fluctuating Two-Ray (FTR) model is gaining momentum as a reference fading model in scenarios where two dominant specular waves are present. Despite the numerous research works devoted to the performance analysis under FTR fading, little attention has been paid to effectively understanding the interplay between the fading model parameters and the fading severity. According to a new scale defined in this work, which measures the hyper-Rayleigh character of a fading channel in terms of the Amount of Fading, the outage probability and the average capacity, we see that the FTR fading model exhibits a full hyper-Rayleigh behavior. However, the Two-Wave with Diffuse Power fading model from which the former is derived has only strong hyper-Rayleigh behavior, which constitutes an interesting new insight. We also identify that the random fluctuations in the dominant specular waves are ultimately responsible for the full hyper-Rayleigh behavior of this class of fading channels.

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.

A Novel Ergodic Capacity Formula for Two-Wave with Diffuse Power Fading Channels

A Novel Ergodic Capacity Formula for Two-Wave with Diffuse Power Fading Channels

Performance of multihop detect‐and‐forward relaying system over fluctuating two‐ray fading channels

AbstractThe performance of multihop detect‐and‐forward relaying system is analyzed over fluctuating two‐ray fading channels for 28 GHz millimeter wave communications. Exact closed‐form expressions for outage probability and average symbol error rate of various modulation schemes over nonidentically distributed fluctuating two‐ray fading channels have been obtained. The derived expressions are given in terms of the Lauricella hypergeometric functions and . Moreover, the derived expressions also accommodate several others reported results in the literature for two‐wave diffuse power, Rician, Rician shadowed, Nakagami‐m, and Hoyt fading channels. Asymptotic outage probability and average symbol error rate expressions are also derived, which provide useful insights on the factors governing the performance of the considered system. The numerical results have been verified with Monte‐Carlo simulation results.

Performance analysis of QAM for M-SC receiver over TWDP fading channels

ABSTRACTThis paper presents a general expression for the bit-error rate performance of quadrature amplitude modulation (QAM), considering arbitrary branch selection combining (SC) receiver over two-wave diffuse power Fading Channels. The impact on the performance of the M branch-SC receiver, caused by the fading parameters Δ and K, has been analysed for different QAM constellations. The expressions have been numerically evaluated and the results obtained have been verified using Monte Carlo Simulation.