Nakagami Fading Research Articles

Half-Duplex and Full-Duplex Performance Comparison for Different Fading Channel Using HMR Protocol in MIMO Technology

This paper deals with the performance of Half Duplex (HD) and Full Duplex (FD) in different fading channels via relay networks. A new Heterogeneous Multiplex Relay (HMR) protocol is proposed for the achievement of spectrum efficiency over Multiple Input and Multiple Output (MIMO) using HD and FD. The Key idea of the protocol the relay selection among half duplex and full duplex for overcoming fading which achieves diversity and multiplexing gain. The protocol is projected in Massive MIMO with Opportunistic Relay Selection which requires limited feedback/signaling for relay and operation mode selection. The max-min criteria help in finding the best channel which leads to the best relay selection. Consideration of the Coded Cooperation and Successive Interference Cancellation helps recovery of the loss of Multiplexing Gain. Simulation result shows the throughput performance of Heterogeneous Multiplex Relay (HMR) protocol compared to HD and FD. HMR protocol provides 80% capacity performance due to its allotted channels between HD and FD. It also shows the performance of Bit Error Rate (BER) vs Signal to Noise Ratio (SNR) values compared to Rayleigh, Rician, and Nakagami Fading Channels.

The impact of dual‐signal selection and multiple eavesdroppers on secrecy performance in cooperative‐relay systems

This paper investigates the impact of a dual-signal selection (i.e. selection of direct signal and relay signal) and multiple eavesdroppers on secrecy outage probability in cooperative-relay systems over Nakagami fading channels. This work performs the derivation of the new exact and approximate distributions for the received signal to noise ratio of the dual-signal selection in analytical forms where maximal-ratio combining and selection combining are considered in the presence of multiple eavesdroppers. The lower bounds on the secrecy outage probability of the dual-signal selection are derived for various receiver scenarios over Nakagami fading channels. This paper also quantifies the secrecy diversity order of the proposed scheme and shows that the dual-signal selection provides a secrecy diversity order gain of λ d = m d UM s M u compared to the conventional scheme by the dual-signal selection. From the numerical results, this work observes that the sharpness of the dual-signal selection for the secrecy performance curve is improved by the number of user nodes and fading index of the direct signal, while the number of eavesdroppers and fading index of the eavesdropper slightly affect the required signal to noise ratio of the proposed scheme to satisfy the secrecy outage probability.

Towards a Deep Analysis of Millimeter Wave D2D Underlaid Cellular Networks

This paper provides a deep analysis for millimeter-wave device-to-device (mm-wave D2D) underlaid cellular networks to investigate how the performance of individual users or link percentiles under constraints are affected by the interaction between D2D and cellular communication modes integrated with the salient mm-wave features. Under a general Nakagami fading model, we derive the upper bounds for the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$b$ </tex-math></inline-formula> -moments of the conditional signal-to-interference-noise ratio (SINR) distributions for the two modes given the network realization, and further calculate the upper bounds of SINR meta distributions (MDs). Moreover, we extend the MD-based analysis to evaluate the fine-grained performance for the transmission effectiveness, through deriving the bounding results for the user-perceived rate MD and spatial rate capacity (SRC), the latter of which is defined as the effective density of users satisfying a given transmission rate requirement with a certain probability. Numerical results validate the tightness of the proposed bounds and reveal the different effects of the network configuration parameter associated with mm-wave on the link and network performances from the view of individual users.

Reliability-Guaranteed Admission Control for Mobile Computation Offloading Under Nakagami Fading Channel

The coupled stochastic channel interferences can lead to intermittent connectivity and invalid fragment transmissions, which pose a significant challenge to guarantee the reliability of computation offloading. A wide variety of conventional approaches to making offloading decisions are based on the fundamental condition that channels are sufficiently reliable for completing each transmission session. However, the reliability that a user can successfully offload a computation task before a restricted deadline remains unexplored under the interference channels. In this letter, we focus on the Nakagami- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${m}$ </tex-math></inline-formula> fading channel and propose an analytical framework to characterize the reliability of computation offloading with the restrictions of application deadline and offloading data size in the presence of coupled stochastic interferences. A lower-bound offloading reliability capturing coupled randomness is theoretically derived. Based on the analytical framework, we further propose an admission control method for users to make computation offloading decisions. Simulation results verify our theoretical framework and show the superior performance of the proposed method over other benchmark schemes in terms of guaranteeing reliability.

Intelligent reflecting surfaces with energy harvesting for Nakagami fading channels

Intelligent reflecting surfaces with energy harvesting for Nakagami fading channels

Performance Analysis of Cognitive Radios in a Cooperative Scheme over Nakagami Fading Channels

Radio spectrum is a primary requisite for wireless technologies and sensor networks. Due to the high demand and expense of the radio spectrum, it is guaranteed to extend its efficient utilization it. To expand the effective operation and serviceability of the radio spectrum in wireless communications, the notion of Cognitive Radio (CR) is presented in where the licensed spectrum of Primary User (PU) is used opportunistically by unlicensed CR users without interfering with the prioritized PU data transmission. Usually, a CR system is applied to detect empty radio bands by exploiting well-known spectrum sensing schemes and then unused spectrum is opportunistically used by the CR system. Various channels fading of the radio environment are to be considered while introducing different spectrum sensing approaches. In this regard, sensing time to find a vacant radio spectrum should be maintained minimum to reliably get the desired throughput. In this paper, an agreement issue is addressed between the time required for effective spectrum sensing and the achievable throughput of the CR network. Our proposed model illustrates the achievable throughput of CR node in cooperation provides better performance than stand-alone CR node. This is achieved by addressing the variation of the number of nodes under the Nakagami fading distribution. In conclusion, the maximum throughputs of the cooperative CR nodes are guaranteed as per simulation and data analysis.

Performance Analysis of Cognitive Radios in a Cooperative Scheme over Nakagami Fading Channels

Radio spectrum is a primary requisite for wireless technologies and sensor networks. Due to the high demand and expense of the radio spectrum, it is guaranteed to extend its efficient utilization it. To expand the effective operation and serviceability of the radio spectrum in wireless communications, the notion of Cognitive Radio (CR) is presented in where the licensed spectrum of Primary User (PU) is used opportunistically by unlicensed CR users without interfering with the prioritized PU data transmission. Usually, a CR system is applied to detect empty radio bands by exploiting well-known spectrum sensing schemes and then unused spectrum is opportunistically used by the CR system. Various channels fading of the radio environment are to be considered while introducing different spectrum sensing approaches. In this regard, sensing time to find a vacant radio spectrum should be maintained minimum to reliably get the desired throughput. In this paper, an agreement issue is addressed between the time required for effective spectrum sensing and the achievable throughput of the CR network. Our proposed model illustrates the achievable throughput of CR node in cooperation provides better performance than stand-alone CR node. This is achieved by addressing the variation of the number of nodes under the Nakagami fading distribution. In conclusion, the maximum throughputs of the cooperative CR nodes are guaranteed as per simulation and data analysis.

Modeling and simulation of secure connectivity and hop count of multi-hop ad-hoc wireless networks with colluding and non-colluding eavesdroppers

Connectivity and hop count are two crucial attributes of dynamic wireless networks such as ad-hoc wireless networks (AHWNs). When the security issue is considered, establishing a secure multi-hop path in AHWNs is challenging because an intermediate node having a wireless link with previous nodes may not be secure to receive data from those nodes, and vice versa. In this paper, stochastic geometry graphs is used to model the AHWNs with eavesdroppers’ presence, then a simulation-based analysis method is proposed to investigate the characteristics of connectivity, hop count distribution, average hop count, and their relations in various scenarios. The proposed simulation-based analysis method consists of two algorithms. The first one finds all possible secure communication paths between two arbitrary legitimate users selected as source and destination and returns the shortest path’s hop count. This algorithm utilizes the random locations of legitimate users and eavesdroppers, the wireless channel condition, and the eavesdropper’s operating mode as input data. The second one provides the hop count distribution and the connection probability of the obtained multi-hop path of the first algorithm by averaging a huge number of network topology trials. So far, this paper is the first work that investigates both connectivity and hop count of security-aware multi-hop AHWNs. Moreover, these characteristics of multi-hop AHWNs with colluding eavesdroppers are compared with those of multi-hop AHWNs with non-colluding eavesdroppers and without eavesdroppers. Simulation results show that putting more legitimate users does not greatly improve the quality of the multi-hop path in the non-colluding case compared with that in colluding case. Furthermore, the shape parameter of Nakagami fading has a more substantial effect on the connectivity and hop count than the spread parameter. The results in this paper provide valuable insights in designing and evaluating security-aware multi-hop AHWNs.

Stochastic geometry modeling and analysis of downlink coverage and rate in small cell network

Due to the massive wireless traffic demand in fifth generation (5G) network, small cell have been attracted growing attention as a key solution and scalable approach for 5G deployments. However, to provide appropriate Quality of Service (QoS), mobile service providers need to study and analyze coverage with and without interference coordination. In this paper, we provide an analytical framework based on Stochastic Geometry to investigate downlink coverage analysis by taking into account mmWave and Nakagami fading. These metrics are analyzed with path loss laws in both cases namely; Line of Site (LOS) and Non Line of Site (NLOS). we derive a general expression of coverage probability according to signal-to-interference-plus-noise ratio (SINR) by assuming directional Beamforming. Then, downlink rate probability is obtained for good network reliability. Moreover, we propose an efficient approach to explore the coverage characteristics under cognitive interference coordination strategies. Finally, simulations results are verified using Monte Carlo Simulations.

Optimal Power Allocation and Harvesting Duration for Cooperative NOMA in the Presence of Nakagami Fading Channels

The paper derives the throughput, outage and packet error probabilities of cooperative non-orthogonal multiple access (NOMA) with energy harvesting. In the first time slot, relay node harvests energy using radio frequency (RF) signal received from the base station (BS). In the second time slot, BS transmits a combination of two symbols $$s_\mathrm{f}$$ and $$s_\mathrm{n}$$ dedicated for far and near users. This signal is received by the two users and a relay. In the third time slot, the relay node amplifies the received signal to the two users. Both users use the signal with the highest signal-to-interference plus noise ratio (SINR) among direct and relayed signals. The far user detects only its symbol. Near user first detects symbol $$s_\mathrm{f}$$ of far user. After removing the contribution of far user, near user detects its own symbol $$s_\mathrm{n}$$ . We propose the use of the gradient algorithm to optimize harvesting duration and the powers allocated to far and near users to maximize the total throughput.

Secrecy Analysis of Relay-User Selection in AS-AF Systems Over Nakagami Fading Channels

This paper presents the secrecy outage probability of relay and user (RU) selection in the antenna selection (AS)-amplify and forward (AF) system over integer-valued $m$ Nakagami fading channels for the physical layer security. This work derives the lower bound (LB) and asymptotic cumulative density functions (CDFs) of the signal to noise ratio (SNR) for the RU selection in the AS-AF system. This study also considers the impact of the two types of receivers, i.e., maximal ratio combining (MRC), selection combining (SC) for the authorized system and eavesdropper. Using the lower bound CDFs, the LB expressions of the secrecy outage probability are derived for various scenarios. Applying the asymptotic CDFs, the diversity order of the secrecy performance is also quantified for each case. From analysis results, we show that the diversity order of the secrecy outage probability in the proposed system is only affected by authorized system's parameters, not by eavesdropper's parameters. Further, the relay and user nodes with the MRC receiver provide the SNR gain compared to the SC receiver regardless of eavesdropper's receiver type. Finally, the secrecy outage probability of the proposed RU system with the SC eavesdropper has the SNR gain compared to the MRC eavesdropper, while the diversity order is identical to each other.

Generalization of Index-Modulation: Breaking the Conventional Limits on Spectral and Energy Efficiencies

In the context of orthogonal frequency-division multiplexing with index modulation (OFDM-IM), this paper first presents an improved index modulation (IIM) technique to address the well-known low spectral efficiency problem of IM techniques in general and OFDM-IM in particular. OFDM-IIM is realized by deriving the minimum required number of subcarriers per group, and the minimum number of active subcarriers in each group, of the conventional OFDM-IM technique. It is proven that OFDM-IIM can deliver higher spectral and energy efficiencies than classical OFDM and OFDM-IM. The gains come at the expense of increased detection complexity. Therefore, a proposal of OFDM with generalized IM (OFDM-GIM) technique is presented, where a variable number of subcarriers per group are allowed to be activated. Two variants of OFDM-GIM are designed based on the activation pattern of the subcarriers: the first achieves superior spectral efficiency with reduced detection complexity as compared to OFDM-IIM, and the second is tailored for low data rate communications with higher energy efficiency requirements. Besides optimal maximum likelihood detection, a less-complex sub-optimal detector is proposed. A closed-form expression for the bit error rate (BER) of OFDM-IIM and the two variants of OFDM-GIM is derived, considering transmissions over Nakagami fading channels and multiple-antenna reception. Finally, OFDM-IIM and OFDM-GIM are compared with state-of-the-art techniques to validate their superiority in terms of BER, achievable rate, and energy efficiency.

Downlink and Uplink Intelligent Reflecting Surface Aided Networks: NOMA and OMA

Intelligent reflecting surfaces (IRSs) are envisioned to provide reconfigurable wireless environments for future communication networks. In this paper, both downlink and uplink IRS-aided non-orthogonal multiple access (NOMA) and orthogonal multiple access (OMA) networks are studied, in which an IRS is deployed to enhance the coverage by assisting a cell-edge user device (UD) to communicate with the base station (BS). To characterize system performance, new channel statistics of the BS-IRS-UD link with Nakagami-$m$ fading are investigated. For each scenario, the closed-form expressions for the outage probability and ergodic rate are derived. To gain further insight, the diversity order and high signal-to-noise ratio (SNR) slope for each scenario are obtained according to asymptotic approximations in the high-SNR regime. It is demonstrated that the diversity order is affected by the number of IRS reflecting elements and Nakagami fading parameters, but the high-SNR slope is not related to these parameters. Simulation results validate our analysis and reveal the superiority of the IRS over the full-duplex decode-and-forward relay.

A Computable Form for LoRa Performance Estimation: Application to Ricean and Nakagami Fading

Emerging applications such as connected farms, wildness monitoring, smart cities, and Factory of the Future leverage emerging Low Power Wide Area Networks (LPWAN), allowing a good trade-off between radio range, data rate, and energy consumption. However, only few theoretical studies of these recent technologies are available to help network designers to optimize real field deployments or even achieve real-time adaptation of transmission parameters. A new approach based on Marcum function is proposed in this paper to estimate – in a fast and accurate manner – the performance in terms of Bit Error Rate of LoRa, one of the most used LPWAN technologies. The method is proposed for Gaussian channels, over challenging propagation environments, i.e., Ricean and Nakagami fadings. Simulation results show that our proposed approximation reduces the approximation error about one order of magnitude compared to existing ones and can be computed by classical software.

基于Málaga湍流信道和Nakagami衰弱信道的选择合并混合FSO/RF系统的性能分析

基于Málaga湍流信道和Nakagami衰弱信道的选择合并混合FSO/RF系统的性能分析

Per User Based Interference Alignment for Uplink CoMP with Perfect CSI under Different Channel Models

Per-user based SLNR-SINR interference alignment (IA) algorithm for uplink CoMP is evaluated under different channel models. Rayleigh, Rician, and Nakagami fading channel is used in transmission with the Additive White Gaussian Noise (AWGN) channel set as reference. Performance evaluation is based on its achievable sum rate and convergence rate by varying the channel, the number of serving cells, and UE's transmit and receive antenna combination. Assuming perfect CSI, the result shows that the maximum achievable sum rate is when the communication occurs in the AWGN channel. There are 3 bps/Hz difference between communication over Rayleigh and Nakagami channel, and 1.5 bps/Hz difference between Rician and Nakagami channel. Among the three fading channels, a smaller number of transmitting and receiving antenna in UE resulted in a higher sum rate with 58.97 bps/Hz for IA in the Nakagami channel with {3, 2, 4, 4, 2} configuration. In the low SNR region, the lowest sum rate for this configuration achieves 15.87 bps/Hz for IA in the Rayleigh channel.

Power Distribution of Device-to-Device Communications Under Nakagami Fading Channel

Recently, device-to-device (D2D) communication was designated to work in cellular networks as a new standard to boost their performances. This kind of communication can occur either underlay to the existing cellular infrastructure, or overlay in the industrial scientific and medical (ISM) unused band. In this paper, we consider the case that D2D transmissions take place concurrently with the usual cellular players in the same spectrum band, and thus, controlling the interference caused by the cellular user equipments (UEs) is of crucial importance. In this work, we consider the uplink transmission of a tier of D2D users. Using network model based on stochastic geometry, we express the general cumulative distribution function (CDF) of the D2D transmit power under Nakagami fading channel. Special cases as CDF of the transmit power for Rayleigh fading and noiseless environment were derived. Besides, an upper bound of the general CDF expression is proposed. To deal with D2D lifetime, first, we express the expectation of the transmit power, then we determine the expectation of the devices lifetime and finally, we give an upper bound of this lifetime expectation. Through simulation, the obtained numerical results confirm the effectiveness of the proposed analytic schemes.

Deep Learning-Based Power Control Scheme for Perfect Fairness in Device-to-Device Communication Systems

The proximity-based device-to-device (D2D) communication allows for internet of things, public safety, and data offloading services. Because of these advantages, D2D communication has been applied to wireless communication networks. In wireless networks using D2D communication, there are challenging problems of the data rate shortage and coverage limitation due to co-channel interference in the proximity communication. To resolve the problems, transmit power control schemes that are based on deep learning have been presented in network-assisted D2D communication systems. The power control schemes have focused on enhancing spectral efficiency and energy efficiency in the presence of interference. However, the data-rate fairness performance may be a key performance metric in D2D communications, because devices in proximity can expect fair quality of service in the system. Hence, in this paper, a transmit power control scheme using a deep-learning algorithm based on convolutional neural network (CNN) is proposed to consider the data-rate fairness performance in network-assisted D2D communication systems, where the wireless channels are modelled by path loss and Nakagami fading. In the proposed scheme, the batch normalization (BN) scheme is introduced in order to further enhance the spectral efficiency of the conventional deep-learning transmit power control scheme. In addition, a loss function for the deep-learning optimization is defined in order to consider both the data-rate fairness and spectral efficiency. Through simulation, we show that the proposed scheme can achieve extremely high fairness performance while improving the spectral efficiency of the conventional schemes. It is also shown that the improvement in the fairness and spectral efficiency is achieved for different Nakagami fading conditions and sizes of area containing the devices.

Employment of Generalized Receiver in DS-CDMA with STBC over Fading Channels: Capacity and Error Probability

The capacity and error probability of orthogonal space-time block codes (STBCs) are considered for the pulse-amplitude modulation (PAM), phase shift keying (PSK), quadrature-amplitude modulation (QAM) in fading channels. The suggested approach is based on employment of the generalized approach to signal processing in noise over the equivalent scalar additive white Gaussian noise channel with a channel gain proportional to the Frobenius norm of the matrix channel for the STBC. Using this effective channel, the capacity and probability of error expressions are derived for the PSK, PAM, and QAM modulation with space-time block coding. The Rayleigh, Rician and Nakagami fading channels are considered. As an application, these results are extended to obtain the capacity and probability of error for a multiuser direct sequence code-division multiple-access (CDMA) system constructed on the basis of the generalized approach to signal processing in noise employing the space-time block coding.

Signal Processing by Generalized Receiver Using DS-CDMA with STBC Technology in Multidimensional Systems over Fading Channels: Capacity and Error Probability

The capacity and error probability of orthogonal space-time block codes (STBCs) are considered for the pulse-amplitude modulation (PAM), phase shift keying (PSK), quadrature-amplitude modulation (QAM) in fading channels. The suggested approach is based on employment of the generalized approach to signal processing in noise over the equivalent scalar additive white Gaussian noise channel with a channel gain proportional to the Frobenius norm of the matrix channel for the STBC. Using this effective channel, the capacity and probability of error expressions are derived for the PSK, PAM, and QAM modulation with space-time block coding. The Rayleigh, Rician and Nakagami fading channels are considered. As an application, these results are extended to obtain the capacity and probability of error for a multiuser direct sequence code-division multiple-access (CDMA) system constructed on the basis of the generalized approach to signal processing in noise employing the space-time block coding