95 documents found, page 1 of 10
Frame recovery using multiple images in rolling shutter based systems
Rêgo, Miguel; Perez, Joaquin; Fonseca, Pedro; Alves, Luis NeroAn algorithm for recovering transmitted static identifiers (IDs) in rolling shutter based Optical Camera Communication systems is proposed by the authors, considering a system comprised of a camera and a circular light source. The goal is to allow the correct decoding when the ID frame is only partially detected in the image. A baseline algorithm as reference for the frame recovery success rate (FRSR) and a rec...
Carrier synchronisation in multiband carrierless amplitude and phase modulation...
Rodrigues, Luís; Figueiredo, Mónica; Alves, Luis Nero; Ghassemlooy, ZabihThe technical feasibility of developing an Internet of Things multi‐user communication system is evaluated based on a central digital multiband carrierless amplitude and phase transmitter, which broadcasts data on multiple channels for a number of low‐cost/low power devices. It addresses the issue of carrier synchronisation, which is critical in realworld implementations because of imperfections of devices and ...
A unilateral 3D indoor positioning system employing optical camera communications
Younus, Othman Isam; Chaudhary, Neha; Ghassemlooy, Zabih; Alves, Luis Nero; Zvanovec, Stanislav; Pattas, Dimitrios; Papanikolaou, Vasilis K.This article investigates the use of a visible light positioning system in an indoor environment to provide a three dimensional (3D) high‐accuracy solution. The proposed system leveraged the use of a single light‐emitting diode and an image sensor at the transmitter and the receiver (Rx) respectively. The proposed system can retrieve the 3D coordinate of the Rx using a combination of the angle of arrival and re...
Optimized Analog Multi-Band Carrierless Amplitude and Phase Modulation for Visi...
Rodrigues, Luis; Figueiredo, Mónica; Alves, Luis NeroThis paper presents a multi-user Visible Light Communication (VLC)-based Internet of Things (IoT) system using multi band-Carrierless Amplitude and Phase (m-CAP) modulation for IoT applications. The proposed system uses a digital m-CAP modulator embedded in a ceiling LED light fixture and analog receivers, aiming at low-cost, low-power, and small-sized IoT devices. The performance was evaluated in terms of the ...
Data rate enhancement in optical camera communications using an artificial neur...
Younus, Othman Isam; Hassan, Navid Bani; Ghassemlooy, Zabih; Haigh, Paul Anthony; Zvanovec, Stanislav; Alves, Luis Nero; Le Minh, HoaIn optical camera communication (OCC) systems leverage on the use of commercial off-the-shelf image sensors to perceive the spatial and temporal variation of light intensity to enable data transmission. However, the transmission data rate is mainly limited by the exposure time and the frame rate of the camera. In addition, the camera’s sampling will introduce intersymbol interference (ISI), which will degrade t...
Exploring the design space of relaying neurons for OWC networks at the nanoscale
Pandeirada, João; Alves, Luis Nero; Ghassemlooy, ZabihThis paper presents an extensive study of a proposed architecture for communications in nanodevices. Nanodevices are equipped with optical front ends and brain inspired spiking neural networks in order to process and relay incoming spike information. When deployed in large numbers, they should be able to establish a network by interpreting and forwarding signals from their neighbors. The objective of the networ...
A polynomial analog baseband predistorter for compensation of wireless amplifie...
Kouhini, Sepideh Mohammadi; Jarchlo, Elnaz Alizadeh; Khademi, Sasan; Ghassemlooy, Zabih; Alves, Luis NeroThis paper presents a new analog polynomial pre-distortion circuit using 350nm CMOS technology to reduce the distortion of the power amplifier in wireless communication systems. The proposed pre-distortion circuit uses the polynomial approach. The coefficients of the polynomial are controlled by multiplying them with sufficient digit defined through the indirect learning process to provide best practice lineari...
An artificial neural network equalizer for constant power 4-PAM in optical came...
Younus, Othman Isam; Hassan, Navid Bani; Ghassemlooy, Zabih; Zvanovec, Stanislav; Alves, Luis Nero; Haigh, Paul Anthony; Le Minh, HoaIn this paper, for the first time, we propose and validate a nonlinear artificial neural network (ANN) equalizer for constant power pulse amplitude modulation (CP 4-PAM) in an optical camera communication (OCC) system. Using the proposed equalizer, we demonstrate experimental based non-flickering transmission at a data rate of up to 7 kbps using a single light-emitting diode and an image sensor with 30 frames p...
Utilização de dispositivos de onda acústica superficial (SAW) na indústria tran...
Mendes, Joana Catarina; Alves, Luis Nero; Pereira, António B.Os dispositivos de onda acústica superficial ou surface acoustic wave devices (SAW) têm uma aplicação generalizada na substituição de filtros convencionais nos circuitos elétricos há várias décadas. A sua aplicação como sensores é relativamente mais recente. Com efeito, mediante a utilização destes dispositivos, tudo o que afete a velocidade de propagação das ondas acústicas num sólido é suscetível de ser conve...
On the use of amplification in Visible Light Communication systems
Oliveira, Marcelo de; Alves, Luis Nero; Monteiro, Paulo P.; Pohl, Alexandre de Almeida PradoVisible Light Communications (VLC) are an evolving technology that employs LED lamps to transfer data and has the potential to provide increased bandwidth in the following years. However, due to the high attenuation losses in the optical path, VLC systems generally present a short range, reaching distances not longer than a few meters. Although this may be suitable for small environments, there may be scenarios...