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Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

A low-complexity fully connected hybrid precoding design is proposed for multiuser massive MIMO systems over frequency-selective fading channels. Digital precoding and analog precoding are adaptively designed based on instantaneous channel state information (CSI) and statistical CSI to maximize transmission efficiency. Furthermore, a dynamic partially connected structure and a novel beamforming algorithm

A joint user association (UA) and power control (PC) framework is presented for downlink transmission in cellular networks featuring a macro base station (BS) and a collection of unmanned aerial vehicle BSs. The problem is presented as a nonconvex optimization problem in which the aim is to maximize the network utility by taking into account the PC, load balancing, and user fairness. The UA problem

We investigate the performance of a downlink ultra-dense network (UDN) with directional transmissions via stochastic geometry. Considering the dual-slope path loss model and sectored beamforming pattern, we derive the expressions and asymptotic characteristics of the coverage probability and constrained area spectrum efficiency (ASE). Several special scenarios, namely the physically feasible path loss

In hybrid satellite-terrestrial networks (HSTNs), spectrum sharing is crucial to alleviate the “spectrum scarcity” problem. Therein, the transmit beams should be carefully designed to mitigate the inter-satellite-terrestrial interference. Different from previous studies, this letter considers the impact of both nonlinear power amplifier (PA) and large-scale channel state information at the transmitter

In this letter, we derive exact closed-form expressions for the level crossing rate (LCR) and average fade duration (AFD) of the signal envelope in $\mathcal {F}$ composite fading channels. Using the novel expressions, we then investigate the behavior of the LCR and AFD for different multipath fading and shadowing conditions. It is shown that multipath fading has a more significant effect on the LCR

We propose a new approach for maximizing system throughput while simultaneously obtaining optimal-coverage in terms of minimal radio link failure (RLF) rates in 5G heterogeneous ultra-dense networks (HUDN). To overcome the trade-off issue between the system throughput maximization and the coverage optimization where we can hardly achieve both optimality together, we employ a joint method of “iteration

In this letter, we address the issue of beam-squinting encountered in ultra-wideband millimeter wave mobile communication systems. First, the beam-squinting effects on the antenna array gain and the usable bandwidth of these systems are analyzed. The obtained results show that, in ultra-wideband communication systems, beam-squinting causes loss in array gain and limits the achievable capacity. To mitigate

For multiple active spatial modulation (MASM) technique, this letter formulates the minimum number of transmit antennas $(N_{\mathrm {t}})$ and the required number of active RF chains ( $N_{\mathrm {a}}$ ) to support the following two statements. First, it is proven that MASM can achieve similar spectral efficiency to conventional spatial multiplexing (SMx) with smaller $N_{\mathrm {t}}$ and $N_{\mathrm

Recently, Wireless Power Transfer (WPT) technique using a Radio Frequency (RF) signal has been attracting much attention to sustain the lifetime of wireless Internet of Things (IoT) devices. When a power transmission RF signal operates in the same or near the frequency band as a data signal, it may decrease communication performance. In this letter, we have proposed a novel protocol that enables data

This letter designs a correlation-based secure beamformer for correlated multiple-input-single-output wiretap channels with multiple noncollaborating passive single-antenna eavesdroppers. The outage-probability-constrained secrecy rate maximization problem is investigated under the assumption that the source has accurate main channel information and statistical wiretap channel information. As the correlation

Achieving ultra-high reliability for short packets is a core challenge for future wireless communication systems, as current systems are designed only to transmit long packets based on classical information-theoretic principles. To tackle this challenge, this letter relies on multi-hop unmanned aerial vehicle (UAV) relay links to deliver short ultra-reliable and low-latency (URLLC) instruction packets

This letter describes a real-valued sparse Bayesian learning (SBL) approach for massive multiple-input multipleoutput (MIMO) downlink channel estimation. The main idea of the approach is to introduce a certain unitary transformation into pilots, so as to convert complex-valued channel recovery problems into real ones. Due to exploiting the real-valued structure of the data matrices, the new approach

In this letter, a low-complexity iterative detector with frequency domain equalization is proposed for generalized spatial modulation (GSM) aided single carrier (SC) transmissions operating in frequency selective channels. The detector comprises three main separate tasks namely, multiple-input multiple-output (MIMO) equalization, active antenna detection per user and symbol wise demodulation. This

Freshness of status update packets is essential for enabling a wide range of applications in wireless sensor networks (WSNs). Accordingly, we consider a WSN where sensors communicate status updates to a destination by contending for the channel access based on a carrier sense multiple access (CSMA) method. We analyze the worst case average age of information (AoI) and average peak AoI from the view

This letter investigates the physical layer security issue in unmanned aerial vehicle (UAV) communication networks. Specifically, two UAVs transmit confidential messages to their specified ground destinations by sharing the same spectrum, while a ground eavesdropper attempts to wiretap the confidential messages. In the considered scenario, although mutual interferences arising from spectrum sharing

In the wardriving type method proposed in this letter, the localization of the base stations (BSs) is performed based on unscented Kalman filter with state constraints (UKFC). The state vector is formed by the coordinates and velocities of BSs, and the observations are localization measurements made by a mobile station. The localization measurements show that the BSs are situated on a 3D surface, and

Owing to its unparalleled tractability, the Poisson point process (PPP) has emerged as a popular model for the analysis of cellular networks. Considering a stationary point process of users, which is independent of the base station (BS) point process, it is well known that the typical user does not lie in the typical cell and thus may not truly represent the typical cell performance. Inspired by this

Channel estimation is of crucial importance in massive multiple-input multiple-output (m-MIMO) visible light communication (VLC) systems. In order to tackle this problem, a fast and flexible denoising convolutional neural network (FFDNet)-based channel estimation scheme for m-MIMO VLC systems was proposed. The channel matrix of the m-MIMO VLC channel is identified as a two-dimensional natural image

In cell-free (CF) massive MIMO, a large number of access points (APs) distributed over the coverage area jointly serve a set of users over the same time/frequency resources. In this letter, we study the impact of channel non-reciprocity (NRC) and imperfect channel state information in CF massive MIMO systems. We derive analytical expressions of capacity lower bounds, including a physically inspired

Considering a two-user multi-antenna Broadcast Channel, this letter shows that linearly precoded Rate-Splitting (RS) with Successive Interference Cancellation (SIC) receivers is a flexible framework for non-orthogonal transmission that generalizes, and subsumes as special cases, four seemingly different strategies, namely Space Division Multiple Access (SDMA) based on linear precoding, Orthogonal Multiple

Polar codes, with low encoding/decoding complexity and capacity-achieving potential, have drawn much attention recently. It is very critical to study the impact of fading on polar codes implementation into wireless communications. Existing research works on polar codes over the fading channel use simplified fading channel models while further reducing the frame error rate is highly needed. In this

The Inhomogeneous Double Thinning (IDT) approach is a tractable and general approximation for analyzing cellular networks in which the locations of the base stations are spatially correlated. Usually, however, the parameters of the approximation depend on the intensity and the specific parameters of the point process. Therefore, it is often difficult to unveil the impact of the system parameters from

In this letter, we investigate the outage-constrained robust secure design in a multiple-input single-output (MISO) energy harvesting (EH) cognitive radio network (CRN), where the malicious energy receivers (ERs) may wiretap the desired information and hence can be treated as potential eavesdroppers (Eves). In particular, considering a non-linear energy harvesting (EH) model, our objective is to design

Many wireless networks operate in a mobile environment with randomly moving user terminals. This letter analytically characterizes the impact of ground user mobility, propagation environment and channel fading on the outage performance of unmanned aerial vehicle (UAV) communications. Closed-form expressions for the outage probability using the random waypoint model for ground user mobility, UAV channel

This letter investigates a multiple-relay decode-and-forward (DF) network with simultaneous wireless information and power transfer (SWIPT). The relays use the power splitting (PS) technique to receive radio frequency (RF) energy and information simultaneously from the source. To characterize nonlinearity of energy harvesters at the relays, two existing models are adopted, which are the logistic function

This letter investigates the caching and delivery strategies in a multiple-input multiple-output (MIMO) fog radio access network (Fog-RAN). We focus on the small cache size scenario where the accumulated cache memories of all edge nodes (ENs) are not enough to cache the whole database. We propose a new file splitting and placement scheme tailored for the small cache size, which offers the freedom to

This letter considers an uplink short-packet ultra-reliable low latency communications (URLLC) system with finite blocklength (FBL). A quasi-static Rayleigh fading channel is adopted in this letter, and we employ wireless power transfer (WPT) to guarantee the data packets transmission of user equipment (UE). A novel non-orthogonal multiple access (NOMA) scheme with WPT under FBL is first proposed to

In the emerging non-orthogonal multiple access-based unmanned aerial vehicle systems, it is of practical importance to maximize the number of users with satisfied quality-of-service experience by incorporating placement design, admission control, and power allocation. To overcome the combinatorial nature and non-convexity of the above problem, a low-complexity mechanism is proposed based on the penalty

We investigate the importance of weak clusters when modeling a wireless massive MIMO channel. We do this by studying the influence of densely spaced terminals and the number of base-station antennas for a zero-forcing precoded massive MIMO system. In particular, we focus on the influence on the correlation and imbalance between the signals at the terminal antennas, the effective channel-gain, the eigenvalue

This letter provides exact characterization of the contact and nearest-neighbor distance distributions for the ${n}$ -dimensional ( ${n}$ -D) Matérn cluster process (MCP). We also provide novel upper and lower bounds to these distributions in order to gain useful insights about their behavior. The two and three dimensional versions of these results are directly applicable to the performance analyses

In machine-type communication (MTC), since multiple active devices are located randomly in a cell, the arrival time of multiple signals can be different. A priori information on the arrival time of multiple signals is helpful to estimate more specific parameters such as the number of signals, which is essential to employ the successive interference cancellation (SIC) to improve throughput of a non-orthogonal

In this letter, we propose a novel offloading learning approach to compromise energy consumption and latency in a multi-tier network with mobile edge computing. In order to solve this integer programming problem, instead of using conventional optimization tools, we apply a cross entropy approach with iterative learning of the probability of elite solution samples. Compared to existing methods, the

To cause effective interference on eavesdropper with an enhanced security, a secure precise jamming and communication (SPJC) is proposed to radiate the transmit energy of artificial noise (AN) and confidential message (CM) into the neighborhoods of Eve and Bob by using random subcarrier selection, directional modulation, and beamforming under phase alignment constraint (PAC). Here, we propose two good-performance

This letter considers availability maximized ground station (GS) selection for free-space optical (FSO) satellite networks, which is a challenging problem in the area of optical satellite communications. As a main contribution of this letter, we propose to address this problem from a new perspective of mathematical optimization. In particular, we advocate a gradient projection based algorithm after

5G millimeter wave (mmWave) communication is an efficient technique for low delay and high data rate transmission in vehicular networks. Due to the high path loss in 5G mmWave band, 5G base stations need to be densely deployed, which may result in great deployment expenditures. In this letter, we jointly consider a relay selection problem in multihop 5G mmWave device to device (D2D) transmissions and

With the assistance of singular value decomposition (SVD), a multi-beam directional modulation (DM) scheme based on symmetrical multi-carrier frequency diverse array (FDA) is proposed. The proposed DM scheme is capable of achieving range-angle dependent physical layer secure (PLS) transmissions in free space with much lower complexity than the conventional zero-forcing (ZF) method. Theoretical and

In a triple-layer satellite (TLS) network with GEO, MEO and LEO, maintaining connectivity of topology confronts the challenge of intermittent visibility due to periodically orbital motions of nodes. To address this issue, in this letter, we develop a time-relevant graph called as space-time graph (STG) model for depicting the topological structure with fine granularity, by taking into account time-domain

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.