Listar GI-GTEC - Artigos por autor "Castedo, Luis"

Mostrando ítems 21-40 de 79

    • 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 ...

    • Estimation of Laplacian Symbols for Analog Transmission Over MIMO Channels 

      Suárez-Casal, Pedro; Fresnedo, Óscar; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2015-12)
      [Abstract]: The MAP and MMSE estimation of Laplace-distributed symbols transmitted over multiple-input multiple-output channels is studied. This is an important problem in analog joint source channel coding with spiral ...

    • Evaluation of Analog Joint Source-Channel Coding Systems for Multiple Access Channels 

      Fresnedo, Óscar; González-Coma, José P.; Hassanin, Mohamed; Castedo, Luis; Garcia-Frias, Javier (Institute of Electrical and Electronics Engineers, 2015-06)
      [Abstract]: We address the evaluation of low-complexity analog Joint Source Channel Coding (JSCC) methods for the transmission of discrete-time analog symbols over Multiple-Input Multiple-Output (MIMO) Multiple Access ...

    • Experimental Characterization of LTE Wireless Links in High-Speed Trains 

      Domínguez-Bolaño, Tomás; Rodríguez Piñeiro, José; García-Naya, José A.; Castedo, Luis (Hindawi, 2017)
      [Abstract]: Multimedia and data-based services experienced a nonstopping growth over the last few years. People are continuously on the move using devices to access multimedia contents or other data-based services. Due to ...

    • Experimental evaluation of interference alignment for broadband WLAN systems 

      Lameiro, Christian; González Fernández, Óscar; García-Naya, José A.; Santamaría, Ignacio; Castedo, Luis (SpringerOpen & European Association for Signal Processing, 2015)
      [Abstract]: In this paper, we present an experimental study on the performance of spatial interference alignment (IA) in indoor wireless local area network scenarios that use orthogonal frequency division multiplexing ...

    • Experimental evaluation of the WiMAX downlink physical layer in high-mobility scenarios 

      Suárez-Casal, Pedro; Rodríguez Piñeiro, José; García-Naya, José A.; Castedo, Luis (SpringerOpen & European Association for Signal Processing, 2015)
      [Abstract]: The experimental evaluation of the WiMAX downlink physical layer in high-mobility scenarios is extremely difficult to carry out because it requires the realization of measurement campaigns with expensive ...