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The main usage of cellular networks has changed from voice to data traffic, mostly requested by static users. In this paper, we analyze how a cellular network should be designed to provide such wireless broadband access with maximal energy efficiency (EE). Using stochastic geometry and a detailed power consumption model, we optimize the density of access points (APs), number of antennas and users...
Various wearable devices are foreseen to be the key components in the future for vital signs monitoring as they offer a non-invasive, remote and real-time medical monitoring means. Among those, Wireless Body Sensors (WBS) for cardiac monitoring are of prominent help to early detect CardioVascular Diseases (CVD) by analyzing 24/24 and 7/7 collected cardiac data. Today, most of these WBS systems for...
Future mobile communication networks will require enhanced network efficiency and reduced system overhead due to their user density and high data rate demanding applications of the mobile devices. Research on Blind Interference Alignment (BIA) and Topological Interference Management (TIM) has shown that optimal Degrees of Freedom (DoF) can be achieved, in the absence of Channel State Information (CSI)...
This paper investigates the joint robust beamforming and artificial noise design in two-user interference networks, where one of the two pairs is wiretapped by an external eavesdropper, and only imperfect eavesdropper's channel state information (ECSI) is available for the two pairs. Under individual transmission power constraint, our goal is to maximize the worst-case achievable secrecy rate of the...
In this paper, joint sensor localization and synchronization in non-cooperative wireless sensor networks (WSNs) using time-of-arrival (TOA) measurements is studied. In addition to zero-mean errors in TOA measurements we consider other sources of error such as non-line-of-sight (NLOS) propagation and anchor uncertainty to make our technique more useful in practice, where the presence of these errors...
Indoor positioning system is a key component for developing various location based services such as indoor navigation in large complex buildings (e.g., commercial center and hospital). Meanwhile, it is challenging to design a cost effective solution which is able to provide high accuracy. A new method, namely Two-Step Movement (2SM), was proposed in [1] to demonstrate how to build a positioning system...
In a cognitive radio (CR) scenario, we study the joint problem of spectrum sensing and jamming detection. Modelling the scenario as a multiple hypothesis testing problem, we analyse the probability of detection of the optimal detector in the sense of Neyman-Pearson theorem. We derive one exact form in terms of a series and a closed-form version. Moreover, we evaluate the asymptotic probability of...
A distributed antenna system (DAS) architecture is considered to be a key enabler for further Network Virtualization where different network configurations are created as needed by a centralized decision making unit that is typically integrated into the Cloud Radio Access Networks (C-RAN) which offers a potential architecture for 5G wireless communication systems. Many schemes have been proposed for...
In-Band Full-Duplex (FDX) and MultiPacket Reception (MPR) are two transmission technologies that can be used together to improve the overall network capacity. However, the FDX Self-Interference Cancellation (SIC) techniques only filter part of the transmitted signal from the reception. This paper analyses how the FDX SIC residual noise influences the performance of MPR systems. It considers power...
Multiple-input-multiple-output (MIMO) technique for visible light communications (VLC) facilitates higher data rate thanks to parallel data transmission. However, full channel-state information (CSI) is a requirement in a MIMO system at all times for successful data recovery, which is a major challenging factor in mobility and shadowing scenarios. In this paper we introduce a novel approach for a...
This paper analyses the communication performance for visible light communication (VLC) with Manchester encoded amplitude modulation. In particular, it considers the ripple generated by the LED driver as an important noise contribution for VLC. The ripple depends on the oscillation frequency of the converter which typically is chosen to satisfy other performance criteria such as power conversion efficiency...
This work investigates the problem of efficient signalling for optical wireless communication systems in the presence of signal-dependent noise. We propose a novel scheme based on signalling in the square-root domain (as defined by a square-root transform) where the optical channel originally distorted by signal-dependent noise is transformed into a stationary white Gaussian noise channel. The bit...
This paper reports a demonstration of high speed visible light communications using a blue laser diode combined with a remote phosphor. This method both generates white light and supports multi Gb/s communications. Data rates of up to 5.62 Gb/s and 6.52 Gb/s were achieved by using OFDM with fixed-rate and adaptive loading approaches, respectively. A total data rate of 10 Gb/s was found to be achievable...
The problem of bit and power loading for bit rate maximization in OFDM data communications over indoor powerline channels is investigated and a simple method for bit/power allocation in a single cycle of the mains is developed. The proposed solution is based on the so called Zadeh's representation for modelling the linear periodically time-varying behavior of powerline channels. Numerical results...
Spectrum Sensing (SS) constitutes the most critical task in Cognitive Radio ( CR) systems for Primary User (PU) detection. Cooperative Spectrum Sensing (CSS) is introduced to enhance the detection reliability of the PU in fading environments. In this paper, we propose a soft decision based CSS algorithm using energy detection by taking into account the noise uncertainty effect. In the proposed algorithm,...
We study the problem of amplify-and-forward relaying in a hybrid satellite-terrestrial communication system with imperfect channel gains. Signals are received by masked destination earth station (ES) with the help of a relaying ES, situated at the ground with good line-of-sight. No direct transmission is possible from the satellite to the destination ES. The satellite-relay ES link is assumed to be...
In this paper, a new spectrum sensing framework is proposed for radar communications, which recovers other informative states associated with realistic radar environments, e.g. fading channel gains and unknown noise variance, when detecting the occupancy of primary-band. We firstly formulate a dynamic state-space model by full considering the unknown noise variance and time-variant flat fading channel...
This work investigates the joint design of fronthaul compression and precoding for the downlink of Cloud Radio Access Networks (C-RANs). The main goal is that of bringing insight into an aspect of the optimal functional split between Radio Units (RUs) and Central Unit (CU), namely: where should precoding be performed? Unlike previous works, we tackle this issue for a practical scenario with block-ergodic...
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