Average Symbol Error Rate Research Articles

Network Topology Reconfiguration-Based Blind Equalization over Sensor Network.

Distributed in-network processing has garnered much attention due to its capability to estimate the unknown parameter of interest from noisy measurements based on a set of cooperating sensor nodes. In previous studies, distributed in-network processing mainly focused on short-distance communication systems, wherein sensor nodes collect certain parameters of interest within their maximum communication distance. In addition, the estimation of certain parameter vectors of interest from noisy measurements, relying heavily on training signals, is achieved with a non-blind distributed estimation algorithm. However, in some applications, acquiring knowledge of training signals beforehand is difficult. Therefore, it is necessary to perform distributed estimation algorithms for receivers without training signals, a concept known as blind distributed estimation. In this paper, the generalized Sato algorithm is used to design the blind equalizer for the signal estimation. In addition, we consider extending the short-distance communication system to a long-distance communication system for an unmanned aerial vehicle (UAV) cooperating with sensor nodes in the wireless sensor network (WSN). In this scenario, the data signal is transmitted from a UAV to the WSN and is received by sensor nodes. However, the performance of the blind equalizer is susceptible to the transmission channel in long-distance communication systems. Here, we present a network topology reconfiguration approach to address the issue of distributed blind equalization. The objective of the proposed method is to discard the influence of ill-channels on the other sensor nodes by detecting ill-channels and redesigning the sensor node weights. Through computer simulation experiments, we evaluated the performance of the blind equalizer using the average mean square error (MSE) and average symbol error rate (SER). In the results of the computer simulation experiments, the blind equalizer using the proposed method outperformed the conventional methods in terms of prediction accuracy and convergence speed.

Performance analysis of energy harvesting‐enabled relay networks inκ‐μfading channels

AbstractIn this paper, we investigate the performance of an energy harvesting (EH)‐enabled multiple relay network operating over generalized‐fading channels. Our approach involves utilizing a partial relay selection strategy and employing an amplify and forward relay protocol for efficient EH from RF signals. Additionally, we integrate a selection combining scheme at the receiver to combine both direct and relaying path signals. In our research, we first obtain the exact closed‐form expression of the cumulative distribution function (CDF) for the system under investigation. Subsequently, we derive expressions for the outage probability (OP) and the moment generating function (MGF) using the derived CDF expression. Furthermore, with the assistance of a CDF‐based approach, we derive closed‐form expressions for the average symbol error rate (ASER) for coherent quadrature amplitude modulation (QAM) schemes, including rectangular QAM (RQAM) and hexagonal QAM (HQAM). We also analyze the ASER expression for non‐coherent frequency shift keying (NCFSK), leveraging the derived MGF expression. To gain valuable insights into the performance of EH‐enabled multiple relay networks, we assess the asymptotic expression of the OP. The outcomes indicate how the behavior of the system is affected by various factors such as time switching ratio, channel fading components, number of relays, and the distance between nodes. To corroborate the accuracy of the analytical findings, Monte Carlo simulations are executed.

On Secrecy Performance in D-MoSK-Based 3-D Diffusive Molecular Communication System.

This paper studies the secrecy performance in a 3-D diffusive molecular communication system with the general depleted molecule shift keying (D-MoSK) modulation, where a point transmitter Alice transmits through diffusion multiple types of molecules modulation to a legitimate absorbing receiver Bob, suffering the eavesdropping from an absorbing eavesdropper Eve. We first develop a solid theoretical framework to determine the probabilistic distributions for the number of molecules absorbed by Bob and Eve, respectively. Based on the results, we then derive the average symbol error rate (SER) as well as the mutual information of Alice-Bob and Alice-Eve, and further apply the Shannon theory to determine the secrecy capacity of Alice-Bob transmission. We also develop the closed-form results for the optimal detection threshold at Bob to achieve the secrecy capacity, and thus devise a complete algorithm for secrecy capacity maximization. Finally, we provide numerical results to illustrate the secrecy performance in the concerned system.

Multiple HAPS-based space-air-ground network with FSO communication: a performance analysis.

Due to the fact that the existing generation of wireless communication cannot possibly keep up with the current traffic explosion and emerging applications, research and development on next-generation (i.e.,sixth generation, 6G) wireless technologies is being carried out worldwide. In this regard, it is anticipated that the space-air-ground (SAG) network with free space optics (FSO) communication can provide the terabits per second throughput necessary to sustain various potential 6G applications. However, FSO communications are susceptible to atmospheric turbulence, pointing errors, and beam scintillation effects. To remedy the severe atmospheric effects, we propose a multiple high-altitude platform station (HAPS)-based SAG network with a HAPS selection scheme. For the proposed system, we have derived the closed-form expressions for outage probability, average symbol error rate (SER), ergodic capacity, and outage capacity over Málaga distribution with pointing errors. Further, the asymptotic expressions for outage probability, average SER, and outage capacity were derived to enhance the comprehension of the system from a practical standpoint. It is observed from the numerical results that the multiple HAPS-based FSO system performs better than the existing HAPS-based FSO systems.

Performance Analysis of UAV RF/FSO Co-Operative Communication Network with Co-Channel Interference

The unmanned aerial vehicle (UAV) communication network has emerged as a promising paradigm capable of independent operation and as a relay to enhance communication coverage and efficiency. However, densely distributed terrestrial base stations with shared communication frequencies inevitably generate co-channel interference (CCI). The interference effect can be effectively eliminated by implementing free-space optical (FSO) communication in the UAV communication network. This paper proposes a solution for the UAV communication network to address interference effectively, specifically by employing a hybrid millimeter-wave radio frequency (RF)/FSO communication system. The RF links serve as the primary means of communication, while the FSO links act as a backup means of communication in the case of CCI. The exact outage probability (OP) and average symbol error rate (SER) expressions are derived for the hybrid RF/FSO communication network. The decision to switch between them depends on the signal-to-interference-plus-noise ratio (SINR). Furthermore, the SINR switching threshold value, which satisfies the target SER, has been calculated numerically for the proposed model. Simulation results indicate that the proposed network notably enhances the OP and attains a signal-to-noise ratio gain of approximately 4.6 dB in the average SER, particularly in scenarios where the RF links are subjected to severe interference or adverse weather conditions, as opposed to a pure RF communication network.

Average symbol error rate analysis of reconfigurable intelligent surfaces based free-space optical link over Weibull distribution channels

Optical wireless communication (OWC) enables wireless connectivity using ultraviolet bands, infrared or visible. With its advantages features as high bandwidth, low cost, and operation in an unregulated spectrum. Free-space optical (FSO) communication systems are near terrestrial as a communication link between transceivers, the link is line-of-sight and successfully transmitted optical signals. Nevertheless, the optical signals transmissions over the FSO channels bring challenges to the system. To overcome the challenges posed by the FSO channels, the most common technique is to use relay stations, the most recent is the reconfigurable intelligent surfaces (RISs) technique. This study introduces a Weibull distribution model for a free-space optical communication link with RISs assisted, the parameter used to evaluate the performance of the system is the average symbol error rate (ASER). The RISs effect is examined by considering the influence of the transmitter beam waist radius, shape parameter, aperture radius, scale parameter, and signal-to-noise ratio on the ASER.

Analyzing the Performance of TAS/MRC with Decode-and-Forward Relaying for Multihop Transmission over Fisher-Snedecor F Fading Channels

This study comprehensively assesses a decode-and-forward relaying system that employs Transmit Antenna Selection/Maximal Ratio Combining (TAS/MRC) for multi-hop communication across Fisher-Snedecor F fading channels. The study primarily focuses on the average symbol error rate (ASER) and outage probability (OP) while using cross QAM (XQAM) and rectangular quadrature amplitude modulation (RQAM). The proposed MIMO system effectively decreases the hardware complexity and cost of large antennas by implementing Transmit Antenna Selection (TAS) at the source and relay nodes and Maximum Ratio Combining (MRC) diversity at the destination and relays. Analytical formulations for OP (outage probability) and ASER (average symbol error rate) are derived using PDF (Probability Density Function)-based methods. Monte-Carlo simulations further validate these formulas. The investigation indicates that system performance is improved under conditions of lighter shadowing compared to moderate and extreme shadowing settings. Additionally, increasing the hop count amplifies the observed performance. Moreover, when the fading parameter increases, both the OP and ASER decrease. This study comprehensively examines the impact of many parameters, including m, p, L, R, and o, on the behaviour of the system under Fisher-Snedecor F fading. Based on the findings, the combination of shadowing and multipath fading significantly affects the system's performance, with both m and p significantly influencing this. When examining the Signal-to-Noise Ratio (SNR), a comparison between RQAM and XQAM demonstrates that XQAM is superior. The research uncovers crucial information for planning and executing the TAS/MRC-based MIMO multi-hop communication system. This technology possesses the capability to enhance the effectiveness of similar communication systems, as seen by the encouraging advancements in performance, especially in scenarios including signal attenuation.

Intelligent-reflecting-surfaces-assisted hybrid FSO/RF communication with diversity combining: a performance analysis

Free space optics (FSO) and radio frequency (RF) communication systems exhibit complementary characteristics, with FSO being susceptible to fog, turbulence, and pointing errors, whereas RF is susceptible to rain and small scale fading. These inherent complementary characteristics between FSO and RF communication systems enable the hybrid configuration to effectively alleviate the impact of environmental impediments. This paper presents the performance analysis of an intelligent reflecting surfaces (IRSs)-assisted hybrid FSO/RF system under atmospheric turbulence (AT), pointing errors (PE), small scale fading effects, and attenuation due to climatic conditions such as fog, rain, etc. To characterize the AT, gamma–gamma distribution is used, and the multipath fading in the RF link is modeled using Nakagami-m distribution. At the receiver, signals from both the FSO and RF links are combined using either the selection combining (SC) or maximal-ratio combining (MRC) technique. We derive the exact closed-form expressions for outage probability and average symbol error rate (ASER) for both diversity combining schemes. The proposed system is compared with the direct link (DL) FSO system, IRSs-assisted FSO system, and hybrid FSO/RF system with diversity combining schemes. Further, the performance comparison between the SC and MRC schemes is also reported. Finally, the accuracy of the analytical expressions is verified by utilizing Monte Carlo simulations.

Unified performance parameters for IM/DD techniques over gamma-gamma fading channel with pointing errors

In this paper, we discuss the performance of different intensity modulation direct detection techniques (IM-DD) used in free space optical systems (FSO) under different channel impairments such as path loss, atmospheric turbulence, and pointing errors. We derived unified formulas for each of the average symbol error rate (SER) bounds and outage probability for different modulation techniques: OOK, MPPM, and LMPPM. The accuracy of the obtained formulas is validated through comparison with MC-simulation results. Finally, we investigate the effect of system parameters on FSO link performance.

Performance of GFDM system with channel estimation error over FTR mmWave channels for 5G and beyond communication

Millimeter-wave (mm-Wave) communication are the building block of the beyond 5G (B5G) generations. For mm-Wave communication, the fluctuating two-ray (FTR) fading channels serve as an appropriate model for the small-scale fading. Generalized frequency division multiplexing (GFDM) is envisioned as one of the potential candidate to fulfil the requirements of B5G communication systems. This paper presents the performance analysis of a GFDM system over the FTR fading environment. In this analysis, both GFDM and space–time coded (STC) GFDM system has been considered, and an exact closed-form expression of the average symbol error rate (ASER) is derived for the μ-QAM modulation technique under imperfect channel estimation condition. The simulation results demonstrate excellent agreement with the numerical results obtained for GFDM and STC-GFDM systems with different channel and system parameters such as m, Kf, Δ, TA, RA, ϱA2 and μ. An asymptotic analysis is also done for both systems.

Analysis on the performance of reconfigurable intelligent surface-aided free-space optical link under atmospheric turbulence and pointing errors

<span lang="EN-US">Free-space optical (FSO) communication can provide the cost-efficient, secure, high data-rate communication links required for applications. For example, it provides broadband internet access and backhauling for the fifth-generation (5G) and the sixth-generation (6G) communication networks. However, previous solutions to deal with signal loss caused by obstructions and atmospheric turbulence. In these solutions, reconfigurable intelligent surfaces (RISs) are considered hardware technology to improve the performance of optical wireless communication systems. This study investigates the pointing error effects for RIS-aided FSO links under atmospheric turbulence channels. We analyze the performance of RIS-aided FSO links influenced by pointing errors, atmospheric attenuation, and turbulence for the subcarrier quadrature amplitude modulation (SC-QAM) technique. Atmospheric turbulence is modeled using log-normal distribution for weak atmospheric turbulence. Several numerical outcomes obtained for different transmitter beam waist radius and pointing error displacement standard deviation are shown to quantitatively illustrate the average symbol error rate (ASER).</span>

Analysis on the performance of pointing error effects for RIS-aided FSO link over gamma-gamma channels

In this study, we analysis on the performance of pointing error effects for reconfigurable intelligent surfeces (RISs) aided free-space optical (FSO) communication link over moderate to strong atmospheric turbulence channels. Among these solutions, RISs are considered as hardware technology to improve performance of optical wireless communication systems. Performance evaluation of systems is affected by atmospheric attenuation, pointing errors and moderate to strong atmospheric turbulence channels for quadrature amplitude modulation (QAM) technique. Atmospheric turbulence channel from moderate to strong is modeled using gamma-gamma distribution. Several numerical results obtained the average symbol error rate (ASER) performance versus beam waist radius and signal to noise ratio for three value of pointing error displacement standard deviation. From the results, it is show that with RIS assisted can effectively improve the performance and link distance of the wireless communication systems.

Hybrid classical relay and advanced RISs for performance enhancement of IoT sensor networks with impaired hardware

In this paper, we propose a combination of traditional relay and advanced reconfigurable intelligent surfaces (RISs) in an Internet of things (IoT) sensor network. In particular, due to the long-range transmission from IoT sensor to receiver, a traditional relay is deployed between them. To greatly enhance the reliabilities of IoT-relay and relay-receiver communications, two RIS groups are exploited where each RIS group has multiple RISs distributed in different areas. Since the IoT, relay, and receiver are often low-cost devices, the hardware impairments (HI) are taken into account in the proposed system. We derive the closed-form expressions of average symbol error rate (SER) and capacity of the proposed hybrid RISs and relay aided IoT sensor system affected by HI and with direct IoT-relay and relay-receiver links (called as the hybrid RIS-R-HI-Wi system). Then, the performance of the hybrid RIS-R-HI-Wi system is compared with that of the relevant systems such as the hybrid RIS-R-HI system without direct links (the RIS-R-HI-Wo system), the RIS-R-ideal hardware (ID) systems with and without direct links (the RIS-R-ID-Wi and RIS-R-ID-Wo systems), and the traditional relay systems with HI and ID (the R-HI and R-ID systems). The theoretical expressions are validated through Monte-Carlo simulations. Numerical illustrations show the huge benefits of utilizing multi-RIS and relay in the hybrid RIS-R-HI-Wi system. Therefore, the performance of the RIS-R-HI-Wi system is dramatically higher than that of the RIS-R-HI-Wo and R-HI systems. Moreover, a significant performance loss caused by HI and high carrier frequencies is determined. Thus, the SER and capacity of the RIS-R-HI-Wi, RIS-R-HI-Wo, and R-HI systems are saturated in the high transmit power regime. In this circumstance, various effective methods such as reducing the distortion noises caused by the HI, using the suitable carrier frequencies, and choosing the appropriate locations of the RISs should be applied in the hybrid RIS-R-HI-Wi system for improving the performance significantly.

On the performance of reconfigurable intelligent surface-assisted UAV-to-ground communication systems

In this study, to reduce the average symbol error rate, and improve coverage and reliability of unmanned aerial vehicles (UAVs) to ground communication systems. In this case, we propose a reconfigurable intelligent surfaces (RISs) assisted for UAV to ground communication scheme, where radio frequency (RF) signal generator sends an unmodulated carrier signal from UAVs to the RIS. At reconfigurable intelligent surface, the RIS modulates each signal, and RIS is as a signal generator. We carry out a performance analysis of UAV-to-ground communication systems with RIS-assisted and without RIS for subcarrier quadrature amplitude modulation (SC-QAM) technique. The analytical expressions of average symbol error rare (ASER) and average channel capacity (ACC) is derived. From the results, it is show that with RIS assisted can effectively improve the reliability and coverage of the UAVs to ground communication systems.

On the performance of energy harvesting‐assisted Nth best relay cooperative networks in Nakagami‐m fading

SummaryWe study the energy harvesting (EH)‐assisted system model based on the performance of a dual‐hop cooperative communication system that is subjected to Nakagami‐ fading. Through the partial relay selection method, the selection of th best relay (BR) is performed among amplify and forward (AF) relays, which can harvest energy from radio frequency signals. At the receiver, the selection combining scheme is considered to select between the signals of th best relaying path and the direct path. For this considered system, we compute the closed‐form expressions of outage probability (OP) and the average symbol error rate (ASER) for higher order quadrature amplitude modulation (QAM) techniques, especially for rectangular QAM, cross QAM, and hexagonal QAM. Further, a new moment‐generating function expression is obtained which is used to derive the ASER expression related to the generalized non‐coherent modulation technique. We also give the asymptotic expression of OP to find out the diversity order. Furthermore, we study the effect of fading parameters, th BR, and other factors on system behavior. Finally, we verify the derived expressions with Monte Carlo simulations.

Performance Analysis of NOMA-Based Hybrid Satellite-Terrestrial Relay Networks With CCI

Hybrid satellite-terrestrial relay networks (HSTRNs) which exploit relay cooperative technology in the integrated system of satellites and terrestrial base stations (BSs) are expected to offer enhanced transmission performance benefited from the spatial gain of independent fading paths. To enable multi-user accessing and resource sharing among users, non-orthogonal multiple access (NOMA) technique can be applied in HSTRNs. In this paper, we consider a NOMA-based HSTRN where a satellite transmits signals to a relay base station (RBS) and a destination ground station (DGS), and RBS also serves a cellular user (CU) and DGS simultaneously by leveraging NOMA scheme. We assume that the satellite shares spectrum with a number of cellular small BSs (SBSs), hence SBSs will cause co-channel interference (CCI) to DGS, RBS and CU. We examine the transmission characteristics of the satellite and terrestrial links, and derive the closed-form expressions of the outage probability (OP) and average symbol error rate (ASER) of DGS and CU, respectively. Specially, we consider the effect of perfect and imperfect successive interference cancellation (SIC) on the ASER performance of CU. Then, considering the stochastic characteristics of satellite links and CCI, we analyze the mean energy efficiency (MEE) of the satellite and propose an optimal power allocation scheme which maximizes the MEE of the satellite and achieves system performance optimization. Simulation results demonstrate the effectiveness of the theoretical analysis and the proposed power allocation scheme.

Orthogonal frequency division multiplexing technology based on MATLAB

The subcarriers of an orthogonal frequency division multiplexing (OFDM) system are not identical in the time domain, and their spectra also overlap. As a result, the spectrum is being used effectively. Its effective use of frequency resources and capacity to combat channel fading have made it the de facto technical standard. In wireless communication, numerous pathways in the channel can lead to interference between symbols, known as inter-symbol interference (ISI). This research supplements OFDM systems with some safeguards to eliminate inter-symbol interference. Most traditionally, OFDM symbols have had their post-event sample points duplicated to their beginnings, a process known as Cyclic prefix (CP) padding in the protection interval. In order to further counteract ISI, a protection interval might be added to the beginning of each symbol. An OFDM system's bit error rate (BER) can be decreased by using cyclic prefixes to attenuate inter-code interference. This study explains how OFDM and CP-OFDM work and compares their performance. The primary topic of this study is a contrast between OFDM and CP-OFDM concerning the performance metrics of average symbol error rate (BER) and signal spectrum diagram (PSD).

Multihop IRS-assisted free space optics communication with DF relaying: a performance analysis.

Free space optics communication (FSO) offers several advantages over its counterpart radio frequency (RF) systems in terms of bandwidth, data rates, and cost efficiency. However, FSO, being a line-of-sight (LoS) communication system, is hindered by various environmental factors. In this paper, we propose a multihop decode-and-forward (DF) relaying-based intelligent reflecting surface (IRS)-assisted FSO system with an aim to deal with the impediments in FSO communication, and it is assumed that each IRS consists of multiple reflecting elements. Specifically, we derive end-to-end expressions for cumulative distribution function (CDF) of output instantaneous signal-to-noise ratio (SNR). Furthermore, with the aid of the CDF statistics, we study the performance of the proposed system by obtaining the expressions for outage probability (OP) and average symbol error rate (ASER) in terms of multivariate Fox's H-function. Moreover, we have quantified the system performance by numerical results. The numerical results show that the multihop IRS-assisted FSO system provides better performance when compared to a single-hop IRS-assisted FSO system and multihop FSO system without IRS. Finally, the derived expressions of OP and ASER are validated using Monte-Carlo simulations.

Performance of IRS-Aided FD Two-Way Communication Network With Imperfect SIC

Intelligent reflecting surface (IRS) is a promising technology to deploy reconfigurable and cost-effective next-generation wireless communication systems. In this work, we investigate the performance of an IRS-aided two-way communication network over Rayleigh fading channels, where downlink and uplink transmission between the base station and the user equipment is established in full-duplex mode. We take into account the impact of residual self-interference (RSI), which results from imperfect self-interference cancellation. We derive the analytical expressions of outage probability (OP), asymptotic OP, and obtain diversity order of the system. We also derive ergodic capacity in terms of the Meijer-G function. Further, we derive the analytical expressions of average symbol error rate (ASER) for general order rectangular quadrature amplitude modulation (QAM), cross QAM, and hexagonal QAM. We highlight the impact of reflecting elements, RSI, and other system parameters on the performance of the considered network and also compare the ASER of various QAM constellations. Finally, Monte-Carlo simulations validate the derived analytical expressions.

Performance Analysis and Power Allocation for Spatial Modulation-Aided MIMO-LDM With Finite Alphabet Inputs

In this paper, we study a spatial modulation (SM) aided multiple-input multiple-output (MIMO) layered division multiplexing (LDM) system for broadcast/multicast service delivery in future broadcast/multicast systems. Comprehensive performance analysis and the injection level (IL) optimization are investigated for the SM-aided MIMO-LDM system over correlated Rayleigh fading channels. First, the symbol detection pairwise error probability (PEP) and the average symbol error rate (SER) union bound under joint maximum-likelihood (ML) detection are derived. Second, the spectral efficiency (SE) of the SM-aided MIMO-LDM system with finite alphabet inputs is analyzed. Since the theoretical SE lacks closed-form expression and involves prohibitive computational complexity, we then derive the closed-form lower bounds and tight approximations for the theoretical SE, in which the computational complexity is relieved by several orders of magnitude compared to direct calculation of the theoretical SE. Third, based on the SE analysis, a weighted sum (WS) SE maximization problem with quality of service (QoS) constraints is formulated to optimize IL for the SM-aided MIMO-LDM system. We first demonstrate that WS SE is a unimodal function of IL, and then develop an efficient golden section search (GSS) based algorithm. Simulation results are provided to validate the theoretical analysis. It is shown that our derived SER union bound well matches the simulated SER in the high SNR region. The tightness of the derived closed-form lower bounds and approximations for theoretical SE and the effectiveness of the developed IL optimization algorithm are also verified by simulation results.