In the training process of distributed machine learning, the data possessed at distinct companies usually contain different features. Labels may even be lacked at certain companies. Therefore, one option is that multiple companies perform joint training in the form of federated learning (FL). Existing studies on FL confines to traditional machine learning (ML), including linear regression, logistic

With the rapid development of satellite constellations and mobile devices, multimedia-content transfer in space-air-terrestrial networks (SATNs) has become increasingly popular. Governed by the current internet protocol-based architecture and the distance between the space and the ground, real-time transmissions of multimedia encounter an enormous challenge. Recently, named data networking has been

In the case of natural disaster or emergency rescue, unmanned aerial vehicle (UAV) can be dispatched to the target region and leveraged as aerial relay to track and serve users owning to flexible maneuverability and fast deployment. In this article, a multi-carrier based UAV data relaying and user tracking system is proposed in which the UAV adopts multi-carrier transmission and builds a communication

In this article, we investigate the load balancing in the era of network slicing in radio access network (RAN). In our differentiated coverage RAN slicing scenario, different coverage areas of different slices have an impact on user association with base station (BS) and users’ resources obtained from BSs. Therefore, slices will limit the balance of BSs’ load. Based on this, we mainly construct a performance

The mass machine type communication (mMTC) in 5G requires the technical support of the wireless sensor network (WSN). Compared with homogeneous WSNs, heterogeneous WSNs provide more flexibility and are more in line with the reality. For heterogeneous WSNs, the use of proper routing methods can prolong the lifetime as well as the stability of the system. This paper studies an energy heterogeneous WSN

In this paper, a novel approach of using deterministic multipath arrivals is presented to highlight the relationship between the coherence bandwidth and the root mean square time delay spread. This is done via a measurement campaign that sounds the wireless channel using frequency sweep measurements, where the wireless link is purposefully disturbed by the motion of a reflecting surface mounted to

In this paper, we consider a cooperative relaying system (CRS) empowered by simultaneous wireless information power transfer (SWIPT) and non-orthogonal multiple access (NOMA) where SWIPT and NOMA are implemented for their energy and spectral efficiencies, respectively. We analyze error performance of the considered CRS-SWIPT-NOMA and derive exact closed-form average bit error probability (ABEP) over

Federated learning is a hot topic in the field of multi-source data. It has the advantage that the data cannot be localized, and it has the problems that the parameters of the local model are difficult to integrate and the accuracy of the model is low. In this paper, an improved gradient boosting decision tree (GBDT) federated ensemble learning method is proposed, which takes the average gradient of

Approximate computing (AC) is an emerging embedded computing paradigm whereby accurate arithmetic units (i.e., adders and multipliers) of a computing platform (e.g., CPU, FPGA, ASIC etc.) are replaced by their inexact counterparts. For the applications (e.g., voice, images etc.) where the error induced by inaccurate arithmetic units remains within tolerable limits, AC is a promising technique because

Recently, radio frequency fingerprint (RFF) technique, characterized by unique hardware impairments, has seen vast attention for specific transmitter identification and authorized access. Differential constellation trace figure (DCTF) emerges as an effective image-based RFF method, which forms a stable constellation figure by performing a key differential process. Previous studies that are based on

This paper studies a FD cooperative non-orthogonal multiple access (NOMA) system in terms of pairwise error probability (PEP) while considering imperfect successive interference cancellation (ipSIC). Exact closed-form expressions of the PEP performance for the system users are derived. The PEP expressions are derived under both ideal condition and in the presence of self-interference due to the FD

The scarcity of wireless spectrum resources and high mobility have brought serious challenges to orthogonal frequency division multiplexing (OFDM) communication systems. To improve spectral efficiency and combat fast time-varying channel fading, this paper studies the OFDM system with high mobility based on superimposed pilots, and adopts a basis expansion model (BEM) to describe fast time-varying

This paper presents the angle-of-arrival (AOA) and time-of-arrival (TOA) statistics of multipaths arriving from scatterers with conic spatial density and located on an elliptical disc around the mobile. For simplification of analysis, a common practice in geometric channel modeling of macrocell networks in the open literature is to assume the scatterers to be located on a circular disc around the mobile

Multi-access edge computing (MEC) technology is envisioned as a promising paradigm to achieve the user needs of low-latency applications. Complex computation tasks are offloaded from resource-constrained devices to resource-rich devices to reduce task completion delays. However, given the high-speed mobility of vehicles, the traditional MEC network architecture is insufficient for the Internet of Vehicle

This paper investigates diffraction around building corners in non line-of-sight vehicle-to-vehicle scenario at a typical urban street intersection. Diffraction from building corner depends on several geometrical parameters. Mobile vehicles moving towards a street intersection cause rapid changes in these geometrical parameters. The effect of varying geometrical parameters along with dependence of

The main challenge in visible light communications (VLC) is the low modulation bandwidth of light-emitting diodes (LEDs). This forms a barrier towards achieving high data rates. Moreover, the implementation of high order modulation schemes is restricted by the requirements of intensity modulation (IM) and direct detection (DD), which demand the use of real unipolar signals. In this paper, we propose

In this work we deal with the performance analysis of a cell-edge user with the precoder and equalizer design in a two-user cooperative multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA) system. Since the data rate fairness and outage performance of cell-edge user are crucial issues in MIMO-NOMA systems, we emphasize on how to sort out these issues. To this end, the coefficients

In this paper, we investigate the problem of joint power allocation and collaborative beamforming for physical layer security in underlay cognitive radio non-orthogonal multiple access relay systems. We consider two relaying schemes, i.e., amplify-and-forward and decode-and-forward, with the goal of maximizing the secrecy rate for the central user subjective to the transmit power constraint at the

This paper proposes a deep learning (DL)-based joint channel estimation and signal detection in multi-user orthogonal-frequency division multiplexing-non-orthogonal multiple access (OFDM-NOMA) schemes over Rayleigh fading channels. In the considered model, we assume that channel state information (CSI) is not known at the receivers (users), thus, to obtain CSI responses, we use two type pilot insertions

Passive detection of unmanned aerial vehicle (UAV) is an important part of surveillance. Satellite has the potential to play a key role in many applications of space-air-ground integrated networks (SAGIN). In this paper, we propose a novel passive detection method for UAV based on Rao detection. Two hypotheses of UAV detection features are proposed when constructing the signal model. Under this condition

User activity analysis (UAA) is a promising technology for network management and network security via network traffic. Recently, deep learning (DL) has been applied into network traffic analysis for outstanding performance. These previously proposed network traffic analysis methods generally requires huge amounts of data from network users. In detail, the common methods are to collect these traffic

This paper investigates the problem of improving security at the physical layer of a Millimeter Wave (mmWave) network equipped with multiple Intelligent Reflecting Surfaces (IRSs). In this network, the IRSs help the Base Station (BS) in transmitting its signal to the desired user and at the same time improving the physical layer security of the network by preventing the signal to be received by an

The significant advancement of the internet-of-things has led to a dramatic increase in the number of moving or motionless devices that are connected to the cellular network. For handling such a great number of devices, 5G networks make use of massive MIMO technology. By considering a dynamic model for all channels variation of devices, joint channel estimation and tracking of all devices are studied

The main goal of the cognitive radio network (CRN) is to provide high throughput and ubiquitous data access, but now it is focusing on energy-efficient green CRN. The energy consumption of CRN depends upon the total network time of cognitive users (CUs) and the unbalanced traffic load of CUs (when multiple CUs try to approach the same channel and their time and energy are wasted due to congestion)

This paper investigates pilot and data power allocation for a multi-cell spatially correlated massive multiple-input multiple-output (MIMO) system with imperfect channel state information (CSI). By exploiting the availability of statistical CSI, the uplink closed-form spectral efficiency (SE) expressions are derived for both full covariance knowledge case and no prior statistical information case.

In this paper, we derive a closed-form approximation for the achievable uplink ergodic rate of the users in a single-cell multi-user multiple-input multiple-output (MIMO) system, where the angular domain in the physical channel model is divided into a finite number of separate directions and the base station (BS) is equipped with a large number of antenna elements. Then, we develop an approximation

Ultra Dense Network (UDN) in which Base Stations (BSs) are deployed at an ultra high density is a promising network model of the future wireless generation. Due to ultra densification, reuse of frequency bands with an ultra high density is compulsory for this network. Conventionally, the research on frequency reuse technique such as Fractional Frequency Reuse (FFR) classifies the active users into

In order to facilitate the ubiquitous heterogeneous and medium-independent communication networks, transmitter identification is crucial especially as the number of transmitters becomes tremendous in reality. Since the birth of spread-spectrum communications, pseudo-random identification sequences have been widely adopted due to their preferable nearly Dirac-Delta auto-correlation property, which would

In view of the wireless channel complexity in refuge chamber environments, we parameterize the channel characteristics for reliable signal propagation under line-of-sight (LoS) and non-line-of-sight (NLoS) conditions. According to the Saleh-Valenzuela channel model, the multipath components (MPCs) arrive at the receiver in cluster form. Therefore, clustering algorithms are required to identify clusters

Single-tone and multi-tone transmissions in the narrowband Internet of Things (NB-IoT) uplink system can be accomplished by employing different orthogonal basis. In this paper, we develop an uplink NB-IoT baseband system model and derive the corresponding analytical signal model based on the discrete cosine transform type-I (DCT-I) domain. Basically, the circular convolution and channel matrix diagonalization

With the increasingly widespread applications of Unmanned Aerial Vehicles (UAVs), various critical issues remain to be settled. Among these, connectivity maintenance is one of the most fundamental problems. In this paper, we focus on designing a distributed connectivity preserving framework in a Flying Ad-hoc Network (FANET) in the presence of bridging links, whose existence has a significant impact

Drones, also known as Unmanned Aerial Vehicles (UAVs), are one of the highly emerging technologies of the modern day. Due to their small size, flying capabilities, and complex machinery, drones can be deployed in diverse fields, including agriculture, sports, entertainment, parcel delivery, disaster management, search and rescue, emergency medicine, and healthcare. In case of medical emergency, timely

Deep learning-based automatic modulation recognition (DL-AMR) methods are mainly based on centralized learning and decentralized learning. These methods have been developed for many applications in heterogeneous wireless networks (HWNs). However, the centralized DL-AMR methods involve high communications cost and computation cost and the decentralized DL-AMR methods are not robust since these methods

This study evaluates the physical-layer security for an underlay cognitive radio-based radio frequency (RF)–free space optical (FSO) network. In particular, a multi-antenna secondary source (S) communicates with a multi-aperture secondary destination (D) via M (M ≥ 1) relays with each equips with both a single antenna and a single aperture in the presence of a N (N ≥ 1)-aperture eavesdropper. In addition

Recently, wireless sensor network (WSN) enabled indoor communication provides an effective and flexible method for local area networks mainly in large buildings or in a group of several buildings. Node localization can be considered as a major process which helps to calculate the coordinate points of the unknown nodes with the assistance of known (anchor) nodes. Earlier studies have considered node

This paper analyzes the downlink transmission performance of an aeronautical broadband satellite communication system operating at millimeter wave (mmWave) band. Specifically, by considering that two adjacent satellites cooperatively communicate with an airplane employing an antenna array, we first propose a simple transmit scheme combining Alamouti space time block coding (STBC) with receive beamforming

In this work, we focus on the Vehicle-to-Vehicle (V2V) radio channel characteristics of two vehicles meeting under the same direction condition and the opposite direction condition based on actual measurements. For two different conditions, we analyze and model the channel characteristics of small-scale fading distribution, Power delay profiles(PDP), received power and Doppler spread. Through the judgment

Superposition coding (SC) with successive interference cancellation (SIC) is considered a promising non-orthogonal multiple access (NOMA) technique for improving spectral efficiency recently. In contrast, the residual interference after SIC at the receiver severely degrades the BER performance when applied in underwater acoustic (UWA) channels. In this paper, we propose a receiver that combined SIC

A multiple antenna base station (BS) with an intelligent reflecting surface (IRS) platform, and several single antenna users are considered in the downlink mode. Simultaneous wireless information and power transfer (SWIPT) is utilized by the BS via transmit beamforming to convey information and power to all devices. Each device applies power splitting (PS) to dedicate separate parts of received power

Compared with traditional network structure, cloud-radio access network (C-RAN) can provide higher capacity with lower latency transmission performance. Meanwhile, more user equipment will require more radio remote heads (RRHs) in the same region. This paper studies the cancellation of interference from adjacent RRHs and maximization for sum-rate based on the limitation that imperfect channel state

With an exaggerating upsurge in mobile data traffic, the wireless networks are confronted with a subtle task of enhancing their network capacity. The shortage of spectrum resources creates a jamming situation in the enhancement of network capacity. To overcome this challenge, cellular networks have been persuaded to seek more fruitful radio spectra. That is why the wireless industry has been experiencing

Non-orthogonal multiple access (NOMA) has been recognized as an attractive technique to address the increasing traffic demands for heterogeneous wireless networks. The conventional fast Fourier transform NOMA (FFT-NOMA) system causes inter-user-interference (IUI), and high peak to average power ratio (PAPR) because of the superposition of multiple users on the same frequency subchannel. To reduce the

Due to the increasing demand for higher capacity in mobile communication devices, non-orthogonal multiple access (NOMA) has become a promising technique. Compared to existing orthogonal multiple access methods, NOMA can serve multiple users with better spectral efficiency by allowing co-channel interference, thus its reliability performance over various channel models needs further research. In this

This paper analyze a new cooperative hybrid underlay–overlay cognitive radio non-orthogonal multiple access (CHCR-NOMA) system, where a secondary source and a primary source share a secondary decode-and-forward relay by using NOMA principles. Exact closed-form expressions for the outage probability of both primary and secondary destinations are derived assuming imperfect channel state information (CSI)

In this paper, a novel heuristic diffraction coefficient in the frequency-domain (FD) for non-perfectly conducting wedges and buildings is proposed. The six-terms diffraction coefficient which is an extension of the four-terms UTD coefficient is proposed to include the effect of transmitted ray for a lossy dielectric wedge with arbitrary low wedge angle, thus, attaining the continuity of the total

This paper studies the problem of linear precoding for multiple-input multiple-output (MIMO) communication channels employing finite-alphabet signaling. Existing solutions typically suffer from high computational complexity due to costly computations of the constellation-constrained mutual information. In contrast to existing works, this paper takes a different path of tackling the MIMO precoding problem

A large data rate is an essential requirement of 6G wireless communication systems. Index Modulation (IM) and Orbital Angular Momentum (OAM) which are introduced recently are two high spectral efficiency technologies. In IM, some additional information is conveyed by activating a subset of transmission entities, and OAM is a novel multiplexing scheme, which can be used in short distance wireless communication

Non-sequential ray tracing simulations are commonly employed to model underwater visible light communication (VLC) channels. The accuracy of such simulations highly depends on how well the optical properties of water (i.e., absorption and scattering) as well as scattering phase function (SPF) are modeled in the simulation. Existing empirical models are only a function of chlorophyll concentration and

Subspace coding is a solution to the error-control problem in noncoherent networks using Random Linear Network Coding (RLNC) as a transmission mechanism. In this paper, we propose a secure error-correction scheme based on a codeword selection method called the Subspace Coding Strategy (SCS) along with a permutation step, as a possible solution for secure transmission of data encoded using subspace

An open-loop (OL) method to enable distributed transmit beamforming is presented in this paper. The approach eliminates the need for feedback to distant receive nodes by using multiple tones to set a coherent phase across the distributed array. This arrangement is able to constantly keep the array syn- chronized to avoid the frequency drifting of the local oscillators (LOs) equipped by distributed

Automatic Modulation Classification (AMC) plays an important role in many civilian applications such as spectrum monitoring (SM) and cognitive radio (CR). The majority of the AMC algorithms for MIMO systems are developed for rich scattering environments, which offer a full rank channel matrix. A rank deficient channel such as a keyhole channel severely affects the AMC performance. It is reported that

In this work, we propose the reference signal-aided channel estimation approach which is a crucial requirement to address the realistic performance of spatial media-based modulation (SMBM) systems where the digitally controllable radio frequency mirrors are deployed on the multiple transmit antennas. Accordingly, least squares and linear minimum mean square error-based channel estimation schemes are

The shooting and bouncing ray approach is an important method used in ray-tracing simulations to estimate the propagation of radio waves. However, in this method, unnecessary rays, which are useless for follow-up and consume a large amount of simulation resources, may emerge. This study proposes an artificial intelligence-based acceleration solution, unlike geometry-based approaches in the literature

This paper focuses on performance analysis of Faster than Nyquist (FTN) signaling schemes that employ low-density parity-check (LDPC) codes, trellis-based detector and turbo equalization decoding principle. We propose an optimization procedure for shaping pulse design, that takes into account number of trellis states used for equalization. By using proposed numerical procedure, we identify information

This paper considers the uplink of a massive MIMO system under the multi-keyhole channels. Two capacity bounding techniques, namely use-and-then-forget (UF) and full-side-information (FSI), are used to obtain the achievable rates. With UF scheme, the base station (BS) utilizes the mean value of the effective channel gain to detect the signal, while with the FSI scheme, the BS exploits the full channel

Recently, mobile edge computing(MEC) has attracted considerable research effort, because mobile users can offload some tasks to edge servers that are closer to users than cloud servers for a better computing experience, which can bring enormous potential in next-generation wireless networks(5G). However, when users are moving, they may be far away from the edge server that undertakes the offloading

Non-orthogonal multiple access (NOMA) scheme is strongly recommended due to its ability to serve multiple users sharing the same frequency and time resources for next-generation radio access networks. Index modulation (IM) over the orthogonal frequency division multiplexing (OFDM) system creates a new dimension for data transmission in terms of subcarrier indices selection bits to enhance the spectral

Presently, Secondary Networks (SNs) are gleaned from rising capacity with reducing interference together instead of making them energy-efficient for green communication. This paper proposes an energy-efficient optimization for resources using game in Hybrid Non-orthogonal Multiple Access (HNOMA) based Cognitive Radio Networks (CRNs). For this, also proposes SUs clustering and energy-efficient Power

This paper encounters the problem of multi-cell precoding in downlink transmission of a massive multiple input multiple output (MIMO) system, where a constant envelope precoding (CEP) structure is employed with the aim of alleviating the implementation cost as well as improving the hardware efficiency. For this purpose, first, the optimization problem of the angle of arrival (AoA)-driven multi-cell