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This paper considers the design of hybrid precoders and combiners for mmWave MIMO systems with per-antenna power constraints and the additional limitations introduced by the phase-shifting network in the analog processing stage. Previous hybrid designs were obtained using a total power constraint, but in practical implementations per-antenna constraints are more realistic, specially at mmWave, given...
To make full use of space/air resources, a Space-Air Integrated Network (SAIN) which is a hierarchical network with satellites, airships and hovering Unmanned Aerial Vehicles (UAVs) is constructed. Nowadays, Free Space Optical (FSO) links have been widely applied in SAINs since they provide high-rate and large-capacity data transmission. Unfortunately, the FSO links across the atmosphere would perform...
Millimeter wave multiple-input multiple-output (MIMO) communication systems must operate over sparse wireless links and will require large antenna arrays to provide high throughput. To achieve sufficient array gains, these systems must learn and adapt to the channel state conditions. However, conventional MIMO channel estimation can not be directly extended to millimeter wave due to the constraints...
The idea of combining spatial modulation (SM) with massive multiple-input multiple-output (MIMO) system, i.e. massive SM-MIMO, has recently attracted plenty of academic interest, as it could simultaneously harness the advantages of SM and massive MIMO. However, the spectral efficiency (SE) analysis for massive SM-MIMO is still lack of exploring. To this end, a novel SE expression is derived in this...
In wireless sensor networks, the need for ultra- low power consuming nodes is one of the main motivations for research in such field. Because radio sections in sensor nodes contribute to a large extent to the overall power consumption, the focus of this study is on the RF transceiver. The aim is to reduce the average power consumption which depends significantly on the circuit architecture design,...
In this work, we address the relay selection problem for the wireless powered communication networks, where the relays harvest energy from the source radio frequency signals. A single source- destination pair is considered without a direct link. The connecting relay nodes are equipped with storage batteries of infinite size. We assume that the channel state information (CSI) on the source-relay link...
Radio frequency (RF) recharging can extend maintenance-free operation of wireless sensor networks. However, the period between recharging is limited by the distance between the most distant sensor node and the master which sends out recharging pulses. To increase this period, we propose a scheme in which nodes are logically grouped into circular zones centered at the master, so that nodes in a given...
In this paper, we consider device-to-device (D2D) communication underlaying cellular networks, where D2D users harvest radio frequency (RF) power from uplink cellular transmissions. This paper addresses two important issues for energy harvesting-based D2D cellular networks. The first is how the energy harvested from cellular ambient RF signals affects the D2D spectral efficiency. Using tools from...
Millimeter-wave (mm-Wave) systems with $\mbox{hybrid digital-to-analog beamforming (D-A BF)}$ have the potential to fulfill 5G traffic demands. The capacity of mm-Wave systems is severely limited as each radio frequency (RF) transceiver chain in current base station (BS) architectures support only a particular user. In order to overcome this problem when high density of users are present, a new algorithm...
Multi-Input Multi-Output (MIMO) holds great potential in the high-speed transmission of Visible Light Communication (VLC). However, the inter- channel interference (ICI) in the MIMO-VLC channel is directly related to the geometrical locations of transmitters and receivers, which brings a challenge to the receiver mobility. In this paper, a general design criterion of the channel-adapted space- collaborative...
In cognitive radio (CR), the spectrum sensing of the primary user (PU) may consume some electrical power from the battery capacity of the secondary user (SU), yielding to decrease the transmission power of the SU. In this paper, a multislot simultaneous spectrum sensing and energy harvesting model is proposed, which uses the harvested radio frequency (RF) energy of the PU signal to supply the spectrum...
Visible light communications (VLC) technology has recently emerged as a complementary technology to the indoor radio frequency (RF) networks. While the backhauling of the indoor RF networks has been supported by fiber optics, the backhauling of the VLC network is still an open research problem. Power line communications (PLC) has been considered as a possible solution for the VLC networks due to its...
In this paper, auxiliary beam pair design is developed to provide high-resolution estimates of channel's elevation/azimuth angle-of-departure (AoD) and angle-of-arrival (AoA) for millimeter- wave full-dimension MIMO (FD-MIMO) systems. Pairs of custom designed analog beams are formed at both the transmitter and receiver to help acquire channel information. It is shown via simulation results that by...
Antenna switch enables multiple antennas to share a common RF chain, thus an additional spatial dimension, i.e., antenna index, can be utilized in the design of single RF chain MIMO and information can be conveyed via both signal space and spatial dimension. In this paper, we propose a unified adaptive transmission scheme - adaptive spatial modulation that allocates information into signal space and...
In this paper, we introduce a new model for RF-powered cognitive radio networks with the aim to improve the performance for secondary systems. In our proposed model, when the primary channel is busy, the secondary transmitter is able either to backscatter the primary signals to transmit data to the secondary receiver or to harvest RF energy from the channel. The harvested energy then will be used...
The Internet of Things (IoT) has emerged as one of the focal points in the evolution of cellular networks, and has motivated the introduction of several features that facilitate Machine-Type Communications (MTC) in LTE networks. These features serve the MTC goals of reduced User Equipment (UE) modem cost and complexity, Coverage Enhancement (CE) to support UEs in remote radio locations, and an improved...
Wireless covert systems use low probability of detection (LPD) techniques to hide transmission and protect the transmitter. Traditionally, spread spectrum has been used to hide the covert signal in noise. Recently, research has focused on covert systems that sense the RF channel and hide their transmission in the RF band of a primary network (PN). A widely used metric to quantify covertness is the...
In this paper, we investigate the performance analysis of dual hop relaying system consisting of asymmetric Radio Frequency (RF)/Free Optical Space (FSO) links. The RF channels follow a Rayleigh distribution and the optical links are subject to Gamma-Gamma fading. We also introduce impairments to our model and we suggest Partial Relay Selection (PRS) protocol with Amplify-and-Forward (AF) fixed gain...
The multi-copy routing paradigm in Delay Tolerant Networks (DTNs) implies that increasing contact bandwidth leads to a decrease in data delivery delay and an improvement in throughput. With Hybrid Radio Frequency/Free Space Optical (RF/FSO) PHY layers, the high data rate FSO links can be used to increase the contact bandwidth. However, due to the highly directional nature of FSO links, broadcasting...
In this paper, we study wireless power transfer in a multiuser multiple-input single-output (MISO) system, where a base station equipped with N antennas wirelessly transfers power to distributed single-antenna users. To reduce the implementation cost, we propose a constant-envelope analog beamforming scheme to simultaneously transfer power to multiple users which requires only a single radio frequency...
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