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In this paper, we derive the maximum likelihood (ML) detector for downlink power domain non-orthogonal multiple access (PD-NOMA) in Rician fading channel, to enhance the detection performance of the previously proposed schemes. Then, we modify this ML detector to obtain the boundary based ML (BBML) detector which has much lower computational complexity compared to the original ML while it has the same error probability performance. This detector uses the full statistical channel state information (CSI), and for decision making, compares the received signal with the boundaries obtained based on ML criterion. The delay of this method is less than that of traditional successive interference cancellation (SIC). Analytic and simulation results show that the BBML detector is more efficient than SIC and also previously proposed multi-threshold detector (MTD), in downlink NOMA systems. [ABSTRACT FROM AUTHOR]

Neighbourhood area network (NAN) performance is analyzed with space shift keying (SSK) modulation and energy harvesting-based cooperative amplify-and-forward (AF) relaying. Wifi-enabled home appliances (HAs) can transfer the information to the utility control centre through the smart meter (SM) in the NAN. The HAs in NAN work on a power-saving mechanism, and they drastically increase the spectral efficiency. The Markov chain dynamically models the number of active HAs in the smart grid (SG) network. Moreover, simultaneous wireless information and power transfer combined with AF relaying-based SM helps overcome the rising demands of SG communication by providing an enhanced data rate, low latency, shorter coverage, widespread connectivity of the massive number of devices along with energy-efficiency. Mathematical expressions for average bit error probability are derived for NAN over mixed Saleh–Valenzuela and Rician fading channel based on the multi-user selection combination. The Monte Carlo simulation verifies the numerical results. The result illustrates that the SG NAN performance can be improved by combining SSK modulation with energy harvesting schemes. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles (UAVs), which enable both high flexibility and low cost, have been widely used in both military and civilian application scenarios. In this paper, we investigate a fixed-wing UAV relay system, where the fixed-wing UAV acts as a mobile relay with an elliptical trajectory between base station and ground users with broken communication links because of obstructions. Different time and power allocations are utilized to compute the outage probability among the Rician fading channel model. Due to the complexity of the formulated issue, we approximate the asymptotic solution using the first-order Maclaurin series convex optimization. Finally, we contrast the elliptical trajectory relay's outage probability performance with that of the circular trajectory relay and the fixed relay. In the meanwhile, we examine the impact of the elliptical trajectory's various long and short axis ratios on the outage probability of a relay system. The efficiency of the suggested elliptical trajectory relay method has been demonstrated in simulations. [ABSTRACT FROM AUTHOR]

Recently, academia and industry have shown keen interest in achieving ultra-reliable and low latency communication (URLLC) through short-packet communication to meet the strict demands concerning high reliability and latency for 5G and beyond applications. Un-manned aerial vehicle (UAV) has caught attention recently because of its cost, air time, and mobility, whereas, the non-orthogonal multiple access (NOMA) technique has proven effective in dense user network. Hence, a UAV based system with NOMA has been studied in this paper for remote coverage. In this system, devices communicate to the base station (BS) through a UAV relay where direct link from devices to BS is absent. As UAV has direct line of sight (LOS) to the remote devices, hence, all the analysis is done over a Rician fading channel. In this work, a closed-form expression of average block error rate (BLER) has been formulated for the given system model, which is used as performance metric to analyse the system performance. Moreover, exact BLER expression facilitates in optimization with partial channel state information (CSI) only, which reduces the latency and complexity. Furthermore, we derive an asymptotic expression for BLER in high signal to noise (SNR) regime. Also, a blocklength minimization problem is formulated and optimized with reliability constraints. Simulation results are presented to verify analytical work, as well as comparison of the results with orthogonal multiple access scheme are also shown. [ABSTRACT FROM AUTHOR]

This paper proposes a novel cooperative spectrum sensing network (CSSN) with improved energy detector (IED) based cognitive radio (CR) users. Every CR user is furnished with multiple antennas (M) and performs itself selection combining (SC) operation. All the CRs sense a primary user (PU) via erroneous sensing channels (S) and send the data to a fusion center (FC) via erroneous reporting channels (R). At FC, decision about PU is evaluated with the assistance of k-out-of-N rule. Detection probability expressions for a CR and FC subject to noise plus Rayleigh/Rician fading are developed. Also both simulation and analytical frameworks for throughput analysis are presented. The analytical performance results are also validated using simulation performance results. Performance comparisons between IED and conventional energy detectors (CED) are presented in terms of throughput and total error rate for several parameter values. Further, overall performance of throughput and total error rate in Rayleigh/Rician fading channels is investigated. The joint effects of diversity and fading on the CSSN throughput is also additionally discussed. Channel error (r) impact on the throughput and total error performances for each proposed and traditional networks is studied. Optimization of several parameters for maximizing the throughput and minimizing the total error is also studied. Throughput overall performance of proposed CSSN is plenty better than the conventional network in each fading channel. For several values of M and r, p opt , λ n , opt and N opt values are calculated subject to each fading environment. Both analytical and MATLAB simulation results are matched. Under imperfect channel conditions, performances in terms of throughput and total error are not up to the mark but significant performance improvement has been obtained with diversity at each CR level. [ABSTRACT FROM AUTHOR]

The mid-symbol antenna transition (MAT) approach reduces the number of transmitter antennas in spatial modulation (SM) systems. This paper studies the performance of MAT technique over correlated and uncorrelated wireless channels. We focus on the scenario wherein the channel consists of multiple paths with a line of sight component, i.e., Rician fading channel. An accurate closed form for the average bit error rate (ABER) performance of the MAT approach is derived. Traditional SM, generalized SM (GSM), and variable generalized SM (VGSM) approaches are used as benchmarks to evaluate the considered MAT approach. Simulation results validate the accuracy of the derived ABER closed form. Performance enhancements, in terms of ABER, of the MAT approach compared to SM, GSM, and VGSM approaches are affirmed analytically and by simulation results. [ABSTRACT FROM AUTHOR]

We investigate physical layer security (PLY) of space–time-block-coded (STBC)–multi-input–multi-output (MIMO) wiretap channel in the presence of imperfect channel state information (ICSI) over Rician fading channel. Secrecy for data transmission to legitimate user in the presence of eavesdropper is metered in terms of average secrecy capacity (ASC), probability of non-zero secrecy rate (PNZSR) and secrecy outage probability (SOP). We derive the closed form expression for security parameter by using the probability distribution function and cumulative distribution function of output signal to noise ratio (SNR). Simulation results are presented to validate our analytical results and demonstrate the impact of ICSI on the secrecy performance of STBC–MIMO system. [ABSTRACT FROM AUTHOR]

Recent advances in fifth-generation wireless networks demand quality-of-service (QoS) guarantees to support real-time services such as high-speed mobile networks, autonomous vehicles, and internet-of-things under delay constraints. Since the conventional ergodic capacity proposed by Shannon cannot account for QoS guarantees requirements, a new potential notion was presented to assess the performance of the wireless network in recent studies, which is called the effective capacity (EC). This paper conducts the performance analysis for EC over double shadowed Rician fading channels. To achieve this, the expression for the EC is derived in the closed-form. A truncation error of the expression for the corresponding EC is also derived, which is considerably tight. Furthermore, the consequences of channel and system parameters on the QoS performance of the wireless network are revealed by conducting an asymptotic EC analysis under the sovereignty of high signal-to-noise ratio (SNR). It is found that asymptotic bound for EC is notably tight and asymptotic EC matches with the analytical EC, when SNR is large (e.g. γ ¯ ≥ 20 dB). Additionally, the expressions for the EC of shadowed Rician and Nakagami-q fading channels are deduced as special cases of double shadowed Rician fading. The results for these special cases show similar behaviour of EC as in case of double shadowed Rician fading channels. [ABSTRACT FROM AUTHOR]

This research article presents an innovative approach based on analog network coding (ANC) in conjunction with space time block coding (STBC) which is termed as space time analog network coding (STANC). The STANC investigated as an affective network coding strategy to combat the effects of shadowing and path loss in wireless networks. The another objective of this research work is to evaluate the impact of relay location on system performance in increasing shadowing effect due to increasing tall structure like multistory building in metropolitan area. The performance of the proposed system is analyzed in terms of symbol error rate (SER), STANC gain and ergodic capacity using analytical expressions. Moment generating function approach is used to drive the SER for M-PSK modulated signals. The approximate closed-form expression of ergodic capacity is presented using the derived mean and second moment for STANC based cooperative system. Rician shadowed model is used which efficiently evaluate the effect of shadowing as compared to other fading models given in the literature which is the main advantage of this model. Numerical results signify that the approximated analytical expressions derived can be effectively used for performance improvement under path loss and shadowing effect as compared to simple ANC based system. [ABSTRACT FROM AUTHOR]

Embedding small cells into the conventional macrocell structure of densely populated areas offers numerous benefits for mobile users and operators. The radio-ports of small cells are typically installed to utility posts, customer premises or in residential homes, since they offer a cost-efficient means of increasing the attainable network capacity. Diverse techniques of providing small-cell coverage may be invoked, but unless they use orthogonal resources, they potentially impose additional interference and thus degrade the achievable quality of service. In contrast to previous studies, we analyze the interference distribution (induced by small cells) and the coverage probability from a macrocell user's perspective in the presence of Rician fading. The small cell base station locations are modelled by a homogeneous spatial poisson point process. Our analysis relies on stochastic geometric tools and the results were confirmed by Monte Carlo simulations. [ABSTRACT FROM AUTHOR]