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In this contribution, we focus on a frequency domain two-user Multiple-Input-Single-Output Broadcast Channel (MISO BC) where the transmitter has imperfect and (un)matched Channel State Information (CSI) of the two users in two subbands. We provide an upper-bound to the Degrees-of-Freedom (DoF) region, which is tight compared to the state of the art. By decomposing the subbands into subchannels according...
In the past decades, physical layer security has been extensively studied to exploit fundamental capabilities of physical layer such as randomness in wireless channels, signal-to-noise ratio gap, intended jamming, etc., for secure wireless communications. The notion of secrecy rate plays a crucial role in quantifying the transmission rate for secure communications in the presence of an eavesdropper...
This paper presents an analysis of the performance of a 2×2 MIMO system in off-body communications in a multipath environment. The modelling of wearable antennas in Body Area Networks has been separated into antennas in the vicinity of the body (full wave simulations), including body dynamics (taken from motion capture analysis), and street environment (clusters of scatterers). Multi-Path Components...
In this paper, we study power allocation for secure communication in a multiuser multiple-input single-output (MIS-O) downlink system with simultaneous wireless information and power transfer. The receivers are able to harvest energy from the radio frequency when they are idle. We propose a multi-objective optimization problem for power allocation algorithm design which incorporates two conflicting...
Channel estimation attacks can degrade the performance of the legitimate system and facilitate eavesdropping. It is known that pilot contamination can alter the legitimate transmit precoder design and strengthen the quality of the received signal at the eavesdropper, without being detected. In this paper, we devise a technique which employs random pilots chosen from a known set of phase-shift keying...
In this paper, we present the experimental results forfree space optics (FSO) communication systems operating at visible and near infrared wavelengths (from 0.6 μm to 1.6 μm) under fog conditions. Different empirical fog models are typically used to characterize the fog attenuation of optical beam in FSO systems. A number of empirical fog models are evaluated in order to verify them experimentally...
Singe-carrier frequency-division multiple access (SC-FDMA) enables simplified equalization and flexible multiuser scheduling in the frequency domain. Compared to orthogonal frequency division multiple access (OFDMA), it has reduced envelope fluctuations in the same bandwidth. SC-FDMA is widely used in mobile communications, where the focus is on spectral efficiency. Here, we consider an evolution...
A sparse multipath channel is characterized by a small number of randomly distributed scatterers. This study proposes a methodology for the modelling of sparse multipath channels. The new methodology is then used to develop a sparse narrowband multipath channel model by applying the sum-of-cisoids (SOC) principle. The statistical properties of the presented sparse SOC multipath channel model are studied...
Recently many cellular and WLAN standards are considering operation in the TV bands due to enhanced coverage and access to additional bandwidth. To accurately assess the performance of wireless communication systems operating in the TeleVision White Space (TVWS) spectrum, a new channel model is required that accounts for the unique propagation characteristics in the UHF band. This paper proposes an...
This work introduces a complete framework for three-dimensional (3D) channel extension based on two-dimensional (2D) channel models. In the 3D channel modeling, besides the azimuth angles, the multipath components of a receive-transmit pair are determined by elevation angles, correlations between elevation and azimuth, and the 3D configurations of a user equipment's (UE) location and velocity. The...
This paper presents a empirical model for near human body UWB propagation channel that is valid for the frequency range from 3GHz to 8GHz. It is based on measurements conducted in a anechoic chamber which can be regarded as free space. The empirical model shows the joint propagation characteristics of the on body channel and the channel between body surface and external access point. It includes the...
Massive multiple-input multiple-output (MIMO) systems, where the base station (BS) is equipped with a large number of antennas and the mobile devices have a single antenna, can significantly enhance the system performance. In many wireless systems inter symbol interference (ISI) due to delay dispersion of the channel can dramatically affect the demodulation process of the received signals. Precoding...
This paper investigates the characteristics of the complex received signal in body area networks for two environments at the opposite ends of the multipath spectrum at 2.45 GHz. Important attributes of the complex channel such as the Gaussianity of the quadrature components and power imbalance, which form the basis of many popular fading models, are investigated. It is found that in anechoic environments...
In this work, we evaluate preamble patterns of IEEE P802.15.4k Low Energy Critical Infrastructure Monitoring Networks (LECIM) DSSS PHY. Due to energy constraints of the P802.15.4k systems, preambles should have robust performance to realize high throughput at low Eb/No situations. Our results reveal that the detection performances of the proposed 2-octet and 4-octet preambles are not adequate. For...
Existing methods of self-interference cancellation have greatly reduced the strong self-interference signal for the practical design of Full-Duplex (FuDu) wireless systems. However, current FuDu wireless is hard to be put into practice due to the reason that residual self-interference after interference cancellation is still much stronger than the thermal noise. In this paper, a wideband FuDu OFDM...
This paper describes the performance of MIMO (multiple Input Multiple Output) system using dual-polarized antenna in a IEEE 802.16m. The use of dual-polarized antennas in MIMO systems has emerged as a cost-and space-effective alternative, where two spatially separated uni-polarized antennas can be replaced by a single antenna element employing orthogonal polarizations. Several papers show mainly polarization...
In this paper, we propose a high performance multiple-input and multiple-output (MIMO) detection algorithm for downlink multiuser MIMO (DL MU-MIMO) with practical errors in IEEE 802.11ac systems. The DL MU-MIMO system using the precoding matrix, which is generated through imperfect channel state information caused by channel estimation error and channel feedback quantization error, has severe performance...
In this contribution, a multiple-input multiple-output heterogeneous network with physical-layer network coding is considered. The article proposes a coordinated joint transmitter and receiver design to tackle the interference problem between two-way relaying channel in small cell and uplink channel in macro cell. We design the transceiver on the basis that the data streams from two-way communication...
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