Listar Grupo de Tecnoloxía Electrónica e Comunicacións (GTEC) por autor "Castedo, Luis"

Mostrando ítems 21-40 de 90

    • Analysis, Design and Empirical Validation of a Smart Campus Based on LoRaWAN 

      Fraga-Lamas, Paula; Celaya-Echarri, Mikel; López Iturri, Peio; Fernández-Caramés, Tiago M.; Azpilicueta, Leyre; Aguirre, Erik; Suárez-Albela, Manuel; Falcone, Francisco; Castedo, Luis (MDPI, 2019)
      [Abstract] Internet of Things (IoT) applications for smart environments demand challenging requirements for wireless networks in terms of security, coverage, availability, power consumption, and scalability. The technologies ...

    • Bit Error Probability and Capacity Bound of OFDM Systems in Deterministic Doubly-Selective Channels 

      Domínguez-Bolaño, Tomás; Rodríguez Piñeiro, José; García-Naya, José A.; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2020-10)
      [Abstract]: Doubly-selective channels, such as those that occur when the transmitter and the receiver move relative to each other at high speeds, are a key scenario for fifth generation (5G) cellular systems, which are ...

    • Blind channel identification in Alamouti coded systems: a comparative study of eigendecomposition methods in indoor transmissions at 2.4 GHz 

      Pérez-Iglesias, Héctor J.; García-Naya, José A.; Dapena, Adriana; Castedo, Luis; Zarzoso, Vicente (Wiley, 2008)
      [Abstract]: This paper focuses on blind channel estimation in Alamouti coded systems with one receiving antenna working in indoor scenarios where the flat fading assumption is reasonable. A comparative study of several ...

    • Broadband Access in Complex Environments: LTE on Railway 

      Briso-Rodríguez, Cesar; López, Carlos F.; Fernández, Jean Raphaël Olivier; Pérez Jiménez, Sergio; Draskovic, Drasko; Calle-Sánchez, Jaime; Alonso Montes, José Ignacio; Rodríguez, Carlos; Hernández, Carlos; Molina-García, Mariano; moreno garcia-loygorri, Juan; Rodríguez Piñeiro, José; García-Naya, José A.; Castedo, Luis; Fernandez-Durán, Alfonso (Institute of Electronics, Information and Communication Engineers, 2014)
      [Abstract]: This paper assesses the main challenges associated with the propagation and channel modeling of broadband radio systems in a complex environment of high speed and metropolitan railways. These challenges comprise ...

    • Channel Covariance Identification in FDD Massive MIMO Systems 

      González-Coma, José P.; Suárez-Casal, Pedro; Castro-Castro, Paula-María; Castedo, Luis; Joham, Michael (IEEE, 2018-11)
      [Abstract]: Many channel estimation methods in Massive MIMO FDD systems usually rely on the knowledge of the channel covariance matrix to operate. However, in real scenarios, this covariance is not known beforehand, and ...

    • Channel Estimation and Hybrid Precoding for Frequency Selective Multiuser mmWave MIMO Systems 

      González-Coma, José P.; Rodríguez-Fernández, Javier; Gonzalez-Prelcic, Nuria; Castedo, Luis; Heath, Robert W. (IEEE, 2018-05)
      [Abstract]: Configuring the hybrid precoders and combiners in a millimeter wave multiuser multiple-input multiple-output system is challenging in frequency selective channels. In this paper, we develop a system that uses ...

    • Clock frequency Impact on the performance of high-security cryptographic cipher suites for energy-efficient resource-constrained IoT devices 

      Suárez-Albela, Manuel; Fraga-Lamas, Paula; Castedo, Luis; Fernández-Caramés, Tiago M. (M D P I AG, 2018-12-20)
      [Abstract] Modern Internet of Things (IoT) systems have to be able to provide high-security levels, but it is difficult to accommodate computationally-intensive cryptographic algorithms on the resource-constrained hardware ...

    • Coded Aperture Hyperspectral Image Reconstruction 

      García-Sánchez, Ignacio; Fresnedo, Óscar; González-Coma, José P.; Castedo, Luis (MDPI, 2021)
      [Abstract] In this work, we study and analyze the reconstruction of hyperspectral images that are sampled with a CASSI device. The sensing procedure was modeled with the help of the CS theory, which enabled efficient ...

    • Combining Switched TMAs and FDAs to Synthesize Dot-Shaped Beampatterns 

      Maneiro-Catoira, Roberto; Brégains, Julio; García-Naya, José A.; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2021)
      [Abstract]: The application of frequency offsets to the elements of a conventional phased array with variable phase shifters (VPSs) leads to frequency diverse arrays (FDAs) with the ability to provide range-angle spatial ...

    • Deep Contextual Bandit and Reinforcement Learning for IRS-Assisted MU-MIMO Systems 

      Pereira-Ruisánchez, Dariel; Fresnedo, Óscar; Pérez-Adán, Darian; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2023-07)
      [Abstract]: The combination of multiple-input multiple-output (MIMO) systems and intelligent reflecting surfaces (IRSs) is foreseen as a critical enabler of beyond 5G (B5G) and 6G. In this work, two different approaches ...

    • Design and Experimental Validation of a LoRaWAN Fog Computing Based Architecture for IoT Enabled Smart Campus Applications 

      Fraga-Lamas, Paula; Celaya-Echarri, Mikel; López Iturri, Peio; Castedo, Luis; Azpilicueta, Leyre; Aguirre, Erik; Suárez-Albela, Manuel; Falcone, Francisco; Fernández-Caramés, Tiago M. (MDPI AG, 2019-07-26)
      [Abstract] A smart campus is an intelligent infrastructure where smart sensors and actuators collaborate to collect information and interact with the machines, tools, and users of a university campus. As in a smart city, ...

    • Design and implementation of an OFDMA-TDD physical layer for WiMAX applications 

      Carro Lagoa, Ángel; Suárez-Casal, Pedro; García-Naya, José A.; Fraga-Lamas, Paula; Castedo, Luis; Morales-Méndez, Antonio (SpringerOpen & European Association for Signal Processing, 2013)
      [Abstract]: This work describes the design, implementation, and performance evaluation of an orthogonal frequency division multiple access (OFDMA) time-division duplexing (TDD) physical layer (PHY) compliant with the ...

    • Design of Linear Precoders for Correlated Sources in MIMO Multiple Access Channels 

      Suárez-Casal, Pedro; González-Coma, José P.; Fresnedo, Óscar; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2018-12)
      [Abstract]: This paper focuses on distributed linear precoding when users transmit correlated information over a fading multiple-input and multiple-output multiple access channel. The precoders are optimized in order to ...

    • Design, Implementation and Practical Evaluation of an IoT Home Automation System for Fog Computing Applications Based on MQTT and ZigBee-WiFi Sensor Nodes 

      Froiz-Míguez, Iván; Fernández-Caramés, Tiago M.; Fraga-Lamas, Paula; Castedo, Luis (M D P I AG, 2018-08-13)
      [Abstract] In recent years, the improvement of wireless protocols, the development of cloud services and the lower cost of hardware have started a new era for smart homes. One such enabling technologies is fog computing, ...

    • Direct Antenna Frequency-Hopped M-FSK Modulation With Time-Modulated Arrays 

      Maneiro-Catoira, Roberto; Brégains, Julio; García-Naya, José A.; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2024-02)
      [Abstract]: We present an innovative approach that simultaneously enables direct antenna frequency-hopped M-ary frequency shift keying (DAFH-MFSK) modulation and beamsteering through the use of time-modulated arrays (TMAs). ...

    • Dual-Beam Steerable TMAs Combining AM and PM Switched Time-Modulation 

      Maneiro-Catoira, Roberto; Brégains, Julio; García-Naya, José A.; Castedo, Luis (MDPI, 2022)
      [Abstract] Wireless sensor networks (WSN) are increasingly requiring directional antennas that not only provide higher capacity, security, transmission range or robustness against interference, but also contribute with ...

    • Dual-Signal Transmission Using RF Precoding and Analog Beamforming With TMAs 

      Maneiro-Catoira, Roberto; Brégains, Julio; García-Naya, José A.; Castedo, Luis (IEEE, 2018-06)
      [Absctract]: Time-modulated arrays (TMAs) receiving beamforming provide a noteworthy hardware simplicity given the ability of this multi-antenna technique to transform spatial diversity into frequency diversity. However, ...

    • Dual-Signal Transmission Using RF Precoding and Analog Beamforming With TMAs 

      Maneiro-Catoira, Roberto; Brégains, Julio; García-Naya, José A.; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2018)
      [Abstract]: Time-modulated arrays (TMAs) receiving beamforming provide a noteworthy hardware simplicity given the ability of this multi-antenna technique to transform spatial diversity into frequency diversity. However, ...

    • Emulating extreme velocities of mobile LTE receivers in the downlink 

      Rodríguez Piñeiro, José; Lerch, Martin; García-Naya, José A.; Caban, Sebastian; Rupp, Markus; Castedo, Luis (SpringerOpen & European Association for Signal Processing, 2015)
      [Abstract]: Long-Term Evolution (LTE) is expected to substitute the Global System for Mobile (GSM) Communications as the radio access technology for railway communications. Recently, considerable attention has been devoted ...

    • Enhanced Time-Modulated Arrays for Harmonic Beamforming 

      Maneiro-Catoira, Roberto; Brégains, Julio; García-Naya, José A.; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2017)
      [Abstract]: One of the primary features of time-modulated arrays (TMAs) is their ability to adapt their harmonic patterns to exploit the angular diversity of multipath wireless channels. In such a case, the TMA excitations ...