Joaquin Perez

University of Valencia | UV · Departamento de Ingeniería Electrónica

The radio frequency (RF) laboratory hosted in the Corpuscular Physics Institute (IFIC) of the University of Valencia is designed to house a high-power and high-repetition-rate facility to test normal conduction RF accelerator cavities in the S-Band (2.9985 GHz) in order to perform R&D activities related to particle accelerator cavities. The system,...

Magnetic near-field probes (NFP) represent a suitable tool to measure the magnetic field level from a small electromagnetic interference (EMI) source. This kind of antenna is useful as a magnetic field probe for pre-compliance EMC measurements or debugging tasks since the user can scan a printed circuit board (PCB) looking for locations with strong...

How to design communications systems and its foundations depends on various factors such as the accessibility to learning resources, the academic environment and the audience itself. This article reports how the introduction of learning methodologies based on project based learning (PBL), practical devices and asynchronous working has modified the...

Los dispositivos de radio definida por software se han utilizado en los últimos 6 años como elementos dinamizadores de las prácticas de laboratorio en las asignaturas de la materia de comunicaciones digitales del Grado en Ingeniería Telemática de la Universitat de València. Sin embargo, el desarrollo de estas prácticas requiere el acceso a unos dis...

Beyond 5G networks will be fundamental towards enabling sustainable mobile communication networks. One of the most challenging scenarios will be met in ultra-dense networks that are deployed in densely populated areas. In this particular case, mobile network operators should benefit from new assessment metrics and data science tools to ensure an ef...

The ideal procedure to start designing an electronic device is to consider the electromagnetic compatibility (EMC) from the beginning. Even so, EMC problems can appear afterward, especially when the designed system is interconnected with external devices. Thereby, electromagnetic interferences (EMIs) could be transmitted to our device from power ca...

Vehicle platoons are groups of vehicles that travel together, maintaining a constant distance from each other. Platoons generally require robust and reliable wireless communications to keep their structure and perform coordinated maneuvers. When the platoon is assisted by the infrastructure through a cellular vehicle to anything (V2X) communication...

Resumen-Educational innovation is a process that extends beyond an academic year. In its development, the stages of planning, implementation, evaluation and feedback are distinguished in order to identify aspects that could be improved. In this contribution, we present a procedure for evaluating the impact of the use of software-defined radio devic...

Science, Technology, Engineering, and Mathematics (STEM) are key disciplines towards tackling the challenges related to the Sustainable Development Goals. However, evidence shows that women are enrolling in these disciplines in a smaller percentage than men, especially in Engineering related fields. As stated by the United Nations Women section, in...

La innovación educativa es un proceso que se extiende más allá de un curso académico. En su desarrollo se distinguen las etapas de planificación, implementación, evaluación y realimentación, para identificar aspectos susceptibles de mejora. En esta contribución presentamos el trabajo desarrollado en los dos últimos cursos en la asignatura Teoría de l...

Vehicle platoons involve groups of vehicles travelling together at a constant inter-vehicle distance, with different common benefits such as increasing road efficiency and fuel saving. Vehicle platooning requires highly reliable wireless communications to keep the group structure and carry out coordinated maneuvers in a safe manner. Focusing on inf...

Las Comunicaciones Digitales y el Procesado de Señal para Comunicaciones se enseñan tradicionalmente desde un punto de vista teórico. La complejidad y el coste de los sistemas de radiofrecuencia complica mucho la realización de experiencias prácticas en los laboratorios de Comunicaciones. Sin embargo, la Acreditación Académica actual incluye la dim...

The emerging field of optical wireless communication (OWC) systems is seen as potential complementary technology to the radio frequency wireless communications in certain applications. It is deemed as a possible technology in the future 5th Generation communication networks to address the spectrum congestion and improve the system’s capacity. More...

We propose and analyze a wireless energy and information transmission scheme in free-space optical (FSO) links. The results are presented for both quasi-static and fast-fading conditions. We derive closed-form expressions for throughput, outage probability and optimal power allocation optimizing the system throughput/outage probability. Finally, we...

A novel radio over fiber (RoF) and free space optics (FSO) hybrid system based on optical OFDM (OOFDM) signal transmission is proposed in this paper to provide high capacity optical wireless indoor communication links. A low cost transmission scheme based on IM-DD is proposed to simplify and reuse existing infrastructure to deploy a high bandwidth...

Despite the benefits of free-space optical (FSO) communications, their full utilization is limited by the influence of atmosphere weather conditions. Such as fog, turbulence, smoke, snow and others. In urban environments, additional environmental factor such as smog and dust particles due to air pollution caused by the industry and motor vehicles m...

A new microwave true-time delay (TTD) photonic unit based on the dispersion of PbS colloidal quantum dots (QDs) in a polymethyl methacrylate (PMMA) and the SU8 photoresist is presented. With this aim, the PbS-PMMA and PbS-SU8 nanocomposites are integrated on a silicon platform in the form of the planar and ridge waveguides, respectively. When the P...

In this paper, Vertical-cavity surface-emitting laser (VCSEL) devices are being used in both optical fibre and optical wireless communications. In this paper, the influence of variable polarization angle θp of optical feedback (OF) with the modulation signal on the relative intensity noise (RIN) of VCSEL is experimentally investigated. The RIN char...

Vertical-cavity surface-emitting laser (VCSEL) devices are being used in both optical fibre and optical wireless communications. In this paper, the influence of variable polarization angle θp of optical feedback (OF) with the modulation signal on the relative intensity noise (RIN) of VCSEL is experimentally investigated. The RIN characteristic is p...

A new kind of microwave true time delay (TTD) device based on the dispersion of PbS colloidal quantum dots (QDs) in the commercially available photoresist SU8 is presented. For this purpose PbS-SU8 nanocomposites are integrated on a silicon platform in the form of ridge waveguides. When these structures are pumped at wavelengths below the band-gap...

In free space optical (FSO) communications, several factors can strongly affect the link quality. Among them, one of the most important impairments that can degrade the FSO link quality and its reliability – even under the clear sky conditions – consists of optical turbulence. In this work, the authors investigate the generation of both weak and mo...

We present new kind of microwave phase shifters (MPS) based on dispersion of PbS colloidal quantum dots (QDs) in commercially available photoresist SU8 after a ligand exchange process. Ridge PbS-SU8 waveguides are implemented by integration of the nanocomposite in a silicon platform. When these waveguides are pumped at wavelengths below the band-ga...

In this study, the authors present the measurements performed on a free space optics (FSO) communications link using an indoor atmospheric chamber. In particular, the authors have generated several different optical turbulence conditions, demonstrating how even the weak turbulence regime can strongly affect the FSO link performance. The authors hav...

The performance of a dual parallel differential Mach-Zehnder modulator broadband linearization architecture is analysed. This study provides experimental and analytical results showing an enhancement up to 20 dB in the 3rd-order intermodulation distortion factor at 5 GHz using RF and optical asymmetrical feeding factors.

The influence of variable-polarization optical feedback (VPOF) on the polarization mode switching (PMS) properties of a vertical-cavity surface-emitting laser (VCSEL) has been investigated experimentally. Rotated-polarization optical feedback is considered. At high levels of optical feedback VCSEL exhibits an abrupt PMS when the polarization angle...

This paper investigates the impact of data encryption and decryption in indoor broadcasting visible light communications (VLC) system embedded in the physical layer. The RSA encryption has been implemented to provide a secure data transmission in the physical layer. The paper shows that the bit error rate (BER) performance for the un-secured and se...

Radio-over-fiber architectures conceived for the next generation of wireless access systems are based on Centralized Radio Access Networks (C-RAN), where the baseband processing resources corresponding to different remote base stations (BS) are hosted in a shared central office (CO). We propose the exploitation of the unique features brought by the...

This paper describes the state-of-the-art of polarization multiplexing for optical networks transmission. The use of polarization division multiplexing (PDM) permits to multiply the user capacity and increase the spectral efficiency. Combining PDM and orthogonal frequency division multiplexed (OFDM) modulation allows maximizing the optical transmis...

Optical beams propagating through the turbulent atmospheric channel suffer from both the attenuation and phase distortion. Since future wireless networks are envisaged to be deployed in the ad hoc mesh topology, this paper presents the experimental laboratory characterization of mitigation of turbulence induced signal fades for two ad hoc scenarios...

In this paper the use of hybrid WiMedia-defined ultra-wideband (UWB) and IEEE 802.16d WiMAX radio-over-fibre is proposed and experimentally demonstrated for multi-mode based in-building optical networks with the advantage of great immunity to optical transmission impairments. In the proposed approach, spectral coexistence of both signals must be ac...

Wireless optical links can bring new added technologic approach atop of today's wireless networks forming their backbones and subparts. However several measurements have to be performed in order to get close insight on their availability within infrastructures. The paper reports recent tests at the Czech Technical University in Prague in cooperatio...

Email Print Request Permissions 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...

In this paper, two methods for characterizing fog attenuation in terms of atmospheric visibility V in free space optics (FSO) communications are analyzed and compared. Both methods measure the fog attenuation based on V using a charge-coupled device (CCD) camera and a laser-diode at 0.55 μm. The methods are evaluated in a laboratory controlled FSO...

Free-Space Optical (FSO) communications link performance is highly affected when propagating through the time-spatially variable turbulent environment. In order to improve signal reception, several mitigation techniques have been proposed and analytically investigated. This paper presents experimental results for the route diversity technique evalu...

In this paper we focus in the analysis of the FSO link performance under sandstorms conditions. The sandstorms are characterized by the size of the particles and the necessary wind speed in order to blowing them up during a minimum period of time. Sandstorm is a well know problem in many parts of the world and different reports has been presented r...

In this report we focus in the analysis of the FSO link performance under sandstorms conditions. The sandstorms are characterized by the size of the particles and the necessary wind speed in order to blowing them up during a minimum period of time. Sandstorm is a well know problem in many parts of the world and different reports has been presented...

Reduced visibility significantly affects the transmission of Free Space Optical Links and also is a critical factor in traffic safety. Method for measuring visibility using a digital camera is designed and and tested in this paper. The proposed method is able to measure visibility between two fixed given points and uses the definition of visibility...

In this paper, the attenuation of free space optical (FSO) communication systems operating at selected wavelengths of 0.83 µm, 1.31 µm and 1.55 µm in the controlled laboratory based fog and smoke environments are compared. The fog and smoke are generated and controlled homogeneously along the indoor atmospheric chamber of length 6 m. The experiment...

The paper experimentally investigates the performance of the Ethernet and Fast-Ethernet free space optical (FSO) communications link under the influence of the weak atmospheric turbulence. A dedicated experimental indoor atmospheric chamber is used to generate and control the turbulence conditions that affect the FSO link performance. The chamber i...

In this paper, we compare the fog attenuation of free space optical (FSO) communication systems operating at infrared wavelengths of 830 and 1550 nm in the controlled laboratory based fog environment. The fog is generated and controlled homogeneously along the atmospheric chamber of length 5.5 m. The visibility (V) is measured to characterize the f...

This letter proposes an optimized launch power for the direct detection of optical orthogonal frequency-division multiplexing (DD-OOFDM) for radio-over-flber (RoF). The aim is to optimize the physical layer connectivity for the third generation partnership program-long-term evolution employing RoF technologies. We also analytically derive an expres...

In this letter the performance of a free space optical (FSO) communication link in the presence of fog is experimentally investigated in an indoor environment. A dedicated indoor atmospheric chamber, replicating the outdoor environment, is being used to evaluate the FSO link performance under the fog condition. Theoretical analysis supported by the...

A fast Ethernet 100BASE-TX FSO link performance is evaluated within a dedicated indoor atmospheric chamber performing BER of <;10^-6 under thick fog controlled condition corresponding to an outdoor visibility range higher than 70 m.

In this paper, the effect of turbulence and fog on the free space optical (FSO) communication systems for on-off-keying (OOK), pulse amplitude modulation (PAM) and subcarrier intensity modulation (SIM) based on binary phase shift keying (BPSK) is experimentally investigated. The experiment is carried out in a controlled laboratory environment where...

The 3GPP long term evolution (LTE) standard is continuing to evolve to add more capabilities and enable transmission and reception of even higher data rates [1]. In order to improve the network coverage performance, deployment of large units of LTE base station or eNodeB (eNB) are required. Increasing coverage capacity widely is a critical challeng...

This paper outlines the experimental investigation of the fog effect on the bit error rate (BER) performance of the free space optical (FSO) communication link under a controlled laboratory environment. The link transmittance and the received signal Q-factor are measured against different levels of fog densities. The link visibility derived from fo...

The effect of multi-channel MB-OFDM ultra-wideband radio-over fiber transmission using polarization multiplexing is experimentally analyzed. 25 km SSMF reach is achieved with 1.2% EVM distortion when transmitting three multiplexed channels with 0.7576 Bit/s/Hz spectral efficiency.

Experimental results about the performance of converged radio-over- fiber transmission including multiband-OFDM UWB and WiMAX 802.16 e wireless over a passive optical network are reported in this paper. The experimental study indicates that UWB and WiMAX converged transmission is feasible over the proposed distribution set-up employing a single wav...

The performance of in building distribution of ultra wideband signals is studied experimentally in a laboratory experiment. Analytical and simulation work is also reported confirming the experimental results. The analysis considers multiband-OFDM radio-over-fiber transmission in 300 m of standard single mode fiber and also in multimode fiber for th...

This paper analyzes experimentally the use of distributed feedback lasers (DFB) in order to increase modulation bandwidth in multimode fibres, enabling 3 km bidirectional radio-over-multimode fibre UMTS transmission in a frequency-division duplexing (FDD) configuration.

This paper reports the compared performance of the two main ultra-wideband (UWB) implementations, OFDM-based (OFDM-UWB) and impulse-radio UWB, when transmitted over optical fiber for in-building communications employing external electro-optic modulation. Both UWB implementations providing similar spectral efficiency, 0.378 bit/s/Hz and 0.392 bit/s/...

The photonic generation of millimeter-wave impulse-radio ultra-wideband (UWB) signals is proposed and experimentally demonstrated. Impulse-radio UWB monocycles at 16.85 GHz with 5 GHz bandwidth and bearing data at 1.244 Gbit/s are generated. The frequency up-conversion is performed by a Mach-Zehnder electro-optical modulator (MZM) and the monocycle...

The hybrid wireless-optical transmission of ultra-wideband signals employing orthogonal frequency-division multiplexing modulation (OFDM) ultra-wideband (UWB) as defined in the ECMA-368 standard is experimentally analyzed in this letter. The OFDM-UWB signals provide 400 Mb/s per user at optical distances from 5 to 50 km on standard single-mode fibe...

In this paper, the radio coexistence between a WiMAX 802.16e transmission operating in the 3.5 GHz band and a WiMedia-defined UWB short-range transmission is experimentally studied in a wireless personal area network scenario. Relevant protection margins related to current UWB and WiMAX coexistence are obtained from on-the-field measurements. The c...