Two-wave With Diffuse Power Fading Research Articles

Performance analysis of M-ary RQAM and M-ary DPSK receivers over the channels with TWDP fading

Performance analysis of M-ary RQAM and M-ary DPSK receivers over the channels with TWDP fading

On the Effect of Imperfect Reference Signal Phase Recovery on Performance of PSK System Influenced by TWDP Fading.

We examine the effects of imperfect phase estimation of a reference signal on the bit error rate and mutual information over a communication channel influenced by fading and thermal noise. The Two-Wave Diffuse-Power (TWDP) model is utilized for statistical characterization of propagation environment where there are two dominant line-of-sight components together with diffuse ones. We derive novel analytical expression of the Fourier series for probability density function arising from the composite received signal phase. Further, the expression for the bit error rate is presented and numerically evaluated. We develop efficient analytical, numerical and simulation methods for estimating the value of the error floor and identifying the range of acceptable signal-to-noise ratio (SNR) values in cases when the floor is present during the detection of multilevel phase-shift keying (PSK) signals. In addition, we use Monte Carlo simulations in order to evaluate the mutual information for modulation orders two, four and eight, and identify its dependence on receiver hardware imperfections under the given channel conditions. Our results expose direct correspondence between bit error rate and mutual information value on one side, and the parameters of TWDP channel, SNR and phase noise standard deviation on the other side. The results illustrate that the error floor values are strongly influenced by the phase noise when signals propagate over a TWDP channel. In addition, the phase noise considerably affects the mutual information.

Efficacy of Decentralized CSS Clustering Model Over TWDP Fading Scenario

Cognitive Radio technology, which lowers spectrum scarcity, is a rapidly growing wireless communication technology. CR technology detects spectrum holes or unlicensed spectrums which primary users are not using and assigns it to secondary users. The dependability of the spectrum-sensing approach is significantly impacted from two of the most critical aspects, namely fading channels and neighboring wireless users. Users of non-cooperative spectrum sensing devices face numerous difficulties, including multipath fading, masked terminals, and shadowing. This problem can be solved using a cooperative- spectrum-sensing technique. For the user, CSS enables them to detect the spectrum by using a common receiver. It has also been divided into distributed CSS and centralized CSS. This article compares both ideas by using a set of rules to find out whether a licensed user exists or not. This thought was previously used to the conventional fading channels, such as the Rician, Rayleigh and the nakagami-m models. This work focused on D-CSS using clustering approach over TWDP fading channel using two-phase hard decision algorithms with the help of OR rule as well as AND rule. The evaluation of the proposed approaches clearly depicted that the sack of achieve a detection-probability of greater than 0.8; the values SNR varies between -14 dB to -8 dB. For all two-phase hard decision algorithms using proposed approach and CSS techniques, the detection probability is essentially identical while the value of signal to noise ratio is between -12 dB to -8dB. Throughout this work, we assess performance of cluster-based cooperative spectrum-sensing over TWDP channel with the previous findings of AWGN, Rayleigh, and wei-bull fading channels. The obtained simulation results show that OR-AND decision scheme enhanced the performance of the detector for the considered range of signal to noise ratios.

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.

An Alternative Statistical Characterization of TWDP Fading Model.

Two-wave with diffuse power (TWDP) is one of the most promising models for the description of small-scale fading effects in 5G networks, which employs mmWave band, and in wireless sensor networks deployed in different cavity environments. However, its current statistical characterization has several fundamental issues. Primarily, conventional TWDP parameterization is not in accordance with the model’s underlying physical mechanisms. In addition, available TWDP expressions for PDF, CDF, and MGF are given either in integral or approximate forms, or as mathematically untractable closed-form expressions. Consequently, the existing TWDP statistical characterization does not allow accurate evaluation of system performance in all fading conditions for most modulation and diversity techniques. In this regard, physically justified TWDP parameterization is proposed and used for further calculations. Additionally, exact infinite-series PDF and CDF are introduced. Based on these expressions, the exact MGF of the SNR is derived in a form suitable for mathematical manipulations. The applicability of the proposed MGF for derivation of the exact average symbol error probability (ASEP) is demonstrated with the example of M-ary PSK modulation. The derived M-ary PSK ASEP expression is further simplified for large SNR values in order to obtain a closed-form asymptotic ASEP, which is shown to be applicable for SNR > 20 dB. All proposed expressions are verified by Monte Carlo simulation in a variety of TWDP fading conditions.

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.

Corrections to “Performance Analysis of Nonlinear SFBC OFDM Systems Over TWDP Fading Channel”

The authors inadvertently left out an author to the above paper <xref ref-type="bibr" rid="ref1" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[1]</xref> . His name is Yiming Lei, and he is the corresponding author to this paper.

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.

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.

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.

Performance Evaluation of SFBC MIMO–OFDM Using FrFT Under TWDP Fading Channel

Multiple-input–multiple-output orthogonal frequency division multiplexing (MIMO–OFDM) is a promising 4G technology to increase data rate and capacity of a system. Further, the space–frequency-block-coding (SFBC) technique in MIMO–OFDM system has increased reliability of system in high mobility channels. Fourier transform in conventional OFDM system can obtain either in time or frequency domain, hence it can be acceptable to reduce inter-carrier-interference while it fails for doubly dispersive channels where both the domain are changing simultaneously. Another mathematical tool named as fractional Fourier transform (FrFT) cancels the effect of rapidly varying time–frequency-distortions by considering new rotating axis \(\left( {u,v} \right)\) at an angle \(\alpha\) from conventional time–frequency plane. In this paper, the performance of SFBC encoded MIMO OFDM system using FrFT in place of FFT has been analyzed under two-wave-diffused-power (TWDP) frequency selective fading channel. In this paper, the novel closed form expression for average bit-error-rate (BER) for coded and un-coded FrFT based MIMO–OFDM system under TWDP has also been presented in this paper. The results carried out using simulation shows that the proposed model achieves BER of 10−2 at 5 dB SNR whereas conventional achieves the same at 14 dB hence, concluded that the novel system performance improved by nearly 9 dB.

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.

Accurate Error Probability Analysis of MCIK-OFDM with a Low-Complexity Detection over TWDP Fading Channels

Accurate Error Probability Analysis of MCIK-OFDM with a Low-Complexity Detection over TWDP Fading Channels

Impact of phase noise on single-tap equalization for fast–OFDM signals under generic linear fading channels

In this correspondence, we present the performance evaluation of a low-complexity fast – orthogonal–frequency–division–multiplexing (F–OFDM) scheme, in the presence of phase-noise (PHN), working under the generic linear fading channels (like two-wave-with-diffuse-power (TWDP) multipath fading and modal dispersion in multi-mode-fiber optic channel). Here, a single-tap zero-forcing (ZF) equalizer is utilized to compensate the channel-impulse-response (CIR) without sacrificing data-rate, in which the discrete-cosine-transform (DCT) operation is replaced by the discrete-Fourier-transform (DFT) operation at the receiver. The phase noise variations are modelled by utilizing the random–walk paradigm, in which PHN is dependent on the model parameters/statistics. Therefore, main focus is on the impact of PHN on the performance of single-tap ZF equalization for F–OFDM signals. Simulation results are presented to illustrate efficiency and efficacy of underlying F–OFDM system, while working under TWDP, Rician and Rayleigh multipath fading linear channels. It can be inferred from results that the PHN severely affects/deteriorates the performance of F–OFDM based communication systems in terms of high bit-error-rate (BER), when the PHN variations are large. Moreover, the TWDP fading model is found to be quite appropriate for analyzing/investigating the BER performance of communication systems using the binary-shift-keying modulation technique.

Comprehensive Analysis of the Impact of TWDP Fading on the Achievable Error Rate Performance of BPSK Signaling

Comprehensive Analysis of the Impact of TWDP Fading on the Achievable Error Rate Performance of BPSK Signaling