Hybrid decode-amplify-forward (HDAF) scheme in distributed Alamouti-coded cooperative network

This paper presents the symbol error rate (SER) vs. signal-to-noise (SNR) ratio performance of OFDM system with QAM modulation. It has been observed that the optimal power allocation between pilot and information symbols can improve the performance gain by 2.3 dB relative to the equal power allocation between pilot and information symbols, for a system with N=3D512 sub-carriers, and a channel with L=3D40 taps. The SER performance is then compared with Rayleigh-faded as well as Rician-faded channels. It has been further concluded that the SER vs. SNR performance graph in Rayleigh-faded channel environment is better than that in Rician-faded channel. This idea implies that in OFDM case, the SER vs. SNR performance is better in scattered rich channel environments. The SER vs. SNR performance graph is degraded by equal magnitude for both equal-power and optimal-power cases, which implies that the difference between the equal-power and optimal power case is independent of the channel fading model being used. It is also observed that by varying the standard-deviation of the channel, the SER vs. SNR performance graph is not going to be affected if the channel is considered Rayleigh-faded.

This paper advocates the performance of wireless multiuser relay networks (MRNs) equipped with a single amplify-and-forward (AaF) relay. For such networks, we focus on opportunistic scheduling, in which the destination with the highest instantaneous end-to-end signal-to-noise ratio (SNR) is scheduled for transmission. The scheduled destination can receive either directly from the source or indirectly through the relay, based on cooperative selection diversity (CSD). Assuming Rayleigh fading channels, we first derive a new expression for the cumulative distribution function (CDF) of the received instantaneous end-to-end SNR. Then, relying on this statistical result, we present new exact expressions for the outage probability and symbol error rate (SER), both of which are obtained in closed-form. Furthermore, we derive simple yet valuable closed-form asymptotic expressions for the outage probability and SER in the high SNR regime. Our results explicitly reveal the impacts of CSD and opportunistic scheduling on the diversity order and array gain. Numerical results are presented to validate the analysis.

SER performance investigation of a MPPM relay-aided FSO system with three decision thresholds over EW fading channel considering pointing errors

The use of aerial platforms has recently attracted significant interest in Internet of Things (IoT)-based heterogeneous communication networks to support flexible and efficient network connection. This work investigates the performance of a ground-aerial autonomous aerial vehicle (AAV)-assisted hybrid power line communication (PLC)/free-space optical (FSO) communication system employing both decode-and-forward (DF) and fixed-gain amplify-and-forward (AF) relaying protocols. It is assumed that the PLC channel gain is Log-normally distributed while the Bernoulli-Gaussian random process models the PLC channel noise. The FSO link established between the FSO transmitter and the AAV considers the combined influence of the generalized Málaga distributed atmospheric turbulence (AT), random fog, nonzero boresight pointing errors, and Angle-of-Arrival (AoA) fluctuations of the AAV. Based on this, we evaluate the cumulative distribution function (CDF) and probability density function (PDF) of the end-to-end signal-to-noise ratio (SNR). Further, capitalizing on the statistical characterization of CDF and PDF, we derive series-based expressions for average symbol error rate (ASER), outage probability (OP), and average channel capacity (ACC) utilizing both heterodyne detection (HD) and direct detection (DD) techniques. Additionally, we conduct an asymptotic analysis of ASER in terms of the coding gain and diversity order in a high SNR regime. Likewise, a detailed analysis is carried out to find the optimal value of the field-of-view (FOV) angle and average SNR to achieve minimum ASER under the combined influence of the aforementioned channel conditions using the DF relaying scheme. Furthermore, the impact of all the considered channel parameters and impairments is demonstrated through the numerical results.

This paper deals with the theoretical symbol error rate (SER) performance analysis of coherent square M-QAM in fading channels. The channels in this paper are modeled as frequency non-selective slowly fading channels corrupted by additive white Gaussian noise (AWGN). Closed form expressions for average SERs for square M-QAM in fading channels are derived and analyzed. The solutions presented are in terms of a single finite integral with an integrand composed of elementary (exponential and trigonometric) functions. Because of their simple forms, these expressions readily allow numerical evaluations for cases of practical interest. The dependence of SER performance of M-QAM on Rician parameter K and Nakagami fading parameter m are plotted and examined. The results presented are expected to provide useful information to communication systems design engineers for design and performance evaluation of radio systems over fading channels.

In this paper, we propose a multi-hop multi-branch multiple-input multiple-output (MIMO) SSK scheme with path selection and investigate its error performance. In this scheme, the best path is selected among multiple branches and a multiple-antenna source (S) communicates with a multiple-antenna destination (D) via the relays of the selected path. Each relay is equipped with multiple transmit and receive antennas. It is assumed that there is no direct link between S and D. Moreover, S and all relays employ SSK modulation to transmit information bits and each relay in each path follows the decode-and-forward principle. A closed-form approximate symbol error rate (SER) expression for the proposed SSK system is derived. Furthermore, an asymptotic SER performance analysis is also performed. The analytical results are verified through Monte Carlo simulations. It is shown that the proposed multi-hop SSK system with path selection outperforms conventional multihop M-PSK system with path selection in terms of the SER performance for especially high data rates and sufficient number of receive antennas at the receiving nodes.

Recently, much attention has been drawn to distributed antenna systems (DAS), which are proposed to improve the performance of mobile communication systems. This paper focuses on the analysis of the average symbol error rate (SER) of DAS over a generic composite channel. Initially, a new composite channel model is considered for DAS, which is a mixture of path loss, lognormal shadowing and generalized-Gamma fast fading. This composite channel model is a generic model, which includes many well-known composite channel models as special cases. Based on the channel model, the cumulative distribution function of the output signal-to-noise ratio is obtained by employing selective transmission scheme. Moreover, by averaging the channel conditions and the positions of the MS in the cell, an approximate expression of the average SER is derived, which is a unified form of expression for many commonly used modulation schemes. Numerical results show that the derived expression of the average SER can provide sufficient precision for evaluating the SER performance of DAS under different modulation schemes.

Recently, energy detection (ED) has been investigated in massive single-input multiple-output (SIMO) systems, where transmit symbols can be decoded by averaging the received power across all receive antennas. In this paper, we concentrate on the performance of non-coherent massive SIMO in the presence of antenna correlation. Specifically, closed-form expressions of symbol error rate (SER) and achievable rate are derived. Furthermore, asymptotic behaviors of SER and achievable rate in regimes of a large number of receive antennas, high antenna correlation and large signal-to-noise ratio (SNR) are investigated. Interestingly, the results show that antenna correlation poses a great impact to SER, but has little effect on the achievable rate. Numerical results are presented to verify our analytical results.

In this paper, performance metric of orthogonal frequency division multiplexing (OFDM) system is analyzed over a composite fading channel, i.e., generalized K-fading channel. Here, OFDM system is considered which includes repetition code to enhance the wireless link performance with simplicity. Symbol error rate (SER) performance is evaluated using binary phase shift keying (BPSK) and 16-quadrature amplitude modulation (16-QAM) over generalized K-fading channel. This channel model considers Nakagami-m distribution to define multipath and gamma distribution to represent shadowing effects. Simulation results demonstrate that improved system performance can be achieved by using repetition code in severely faded environment. A comparative study of coded and uncoded system is also given in this paper. Consequently, SER performance is improved with the increase of shape parameters.

Generalized Frequency Division Multiplexing (GFDM) is a flexible multi-carrier transmission to overcome the disadvantages of OFDM. The weakness of GFDM, similarly to the other multicarrier signals, is a high PAPR, large PAPR signals can easily saturate the transmit power amplifier and cause degradation in Symbol Error Rate (SER) performance and Out-of-Band (OOB) emissions. In this paper, we analyze the effects of Non-Linear distortion using the Saleh model in GFDM. We investigate three parameters: CCDF of PAPR, frequency spectrum, and SER. The simulation results show that GFDM superior to OFDM in PAPR performance and spectrum if given the non-linear distortion. But non-linear distortion in GFDM cause SER performance is decreasing significantly while GFDM is less affected by linearity than OFDM.

In high density patterned media storage system, the “multiple islands per read head” model is taken into account for inter-track interference (ITI) in bit-patterned media (BPM). It has been proposed that low-density parity-check (LDPC) codes could improve the symbol error rate (SER) performance significantly when only considering AWGN noise alone over the storage channel. LDPC decoding algorithm could be applied in LDPC joint decoder of patterned media storage system. In this paper, we proposed a decoding algorithm of serial belief propagation (SBP) with a stop updating criterion for LDPC decoder. Simulation results show that the proposed decoding algorithm could reduce the times of generating and propagating the message in decoding with negligible error rate performance loss over AWGN channels when appropriately choosing the parameter that determines which variable node has been converged. By taking advantage of extrinsic information transfer (EXIT) charts, it is demonstrated that the proposed decoding algorithm could maintain superior SER performance and convergence rate compared with the traditional SBP decoding algorithm. To further explore the performance of the proposed decoding algorithm in “multiple islands per read head” model, we performed a large number of simulations over this channel model with different distribution percentages between the AWGN and the island position jitter noise. Simulation results show that the LDPC codes could improve the SER performance when considering jitter noise while the proposed decoding algorithm behaves excellently over the patterned media storage channel and over the AWGN channel.

In this paper, we give an investigation on the performance of cellular dual-hop cooperative communication systems with regenerative relays over flat Rayleigh fading channels. M-ary phase-shift keying (M-PSK) is considered. Two linear diversity reception techniques are adopted in the destination, i.e.,maximal-ratio combining (MRC) and selection combining (SC).We first derive the symbol error rate (SER) expression of dual hop communication with MRC scheme and all relays randomly distributed between the source and the destination. We then derive asymptotic SER expression. With the aid of the a symptotic analysis, asymptotic-optimal power allocation(A-OPA) strategy provides more significant performance improvement compared to equal power allocation (EPA) strategy. Next, we analyze the performance and the asymptotic performance of dual-hop communication with SC scheme.

In this paper, we propose the analytical approach for amplify-and-forward (AF) relay cooperative transmission in the presence of channel estimation error (CEE) generated by pilot symbol assisted-channel estimation (PSA-CE) schemes over quasi-static Rayleigh fading channels. Average symbol error rate (SER) is expressed as the well-known closed-form by using moment generating function (MGF) of the received signal-to-noise ratio (SNR), which quantifies the SNR penalty arising from CEE. Moreover, the effect of CEE on SER performance is verified based on the number of pilot symbols and the accuracy of the derived average SER expression of M-ary phase shift keying (MPSK) is confirmed by comparison with simulation results.

This work presents the approximate symbol error rate (SER) of M-ary phase shift keying (MPSK) for optimum combining (OC) with multiple co-channel interferers in a flat Rayleigh fading channel. The closed-form expression for the ordered mean eigenvalues of interference-plus-noise covariance matrix is derived for the first-order approximation to avoid Monte Carlo simulation and multiple numerical integrals in the cases of arbitrary numbers of interferers and antenna elements. We also derive the closed-form expression for approximate SER of MPSK for OC in terms of the average SER of MPSK for maximal ratio combining (MRC). From the simple evaluation of ordered mean eigenvalues, the first-order approximation gives a simple and accurate way to analyze the performance of OC in the presence of the arbitrary number of interferers.

The channel capacity and probability of outage results for optimum power and rate adaptation (OPRA) and truncated channel inversion with fixed rate (TIFR) schemes over correlated diversity branch obtained so far in literature are applicable only for m ? 1. This paper derived closed-form expressions for the average channel capacity and probability of outage of dual-branch maximal ratio combining (MRC) over correlated Nakagami-0.5 (m < 1) fading channels. This channel capacity and probability of outage are evaluated under OPRA and TIFR schemes. Since, the capacity and probability of outage expressions of dual-branch MRC under OPRA and TIFR schemes contain an infinite series; bounds on the errors resulting from truncating the infinite series have been derived for both average channel capacity and probability of outage. The corresponding expressions for Nakagami-0.5 fading are called expressions under worst fading condition with severe fading. Finally, numerical results are presented, which are then compared to the capacity and probability of outage results that previously published for OPRA and TIFR schemes. It has been observed that OPRA provides improved average channel capacity and probability of outage, as compared to TIFR under worst case of fading. It is also observed that probability of outage under TIFR scheme is not improved adequately than the probability of outage under OPRA even as employing diversity.