Browsing by Author "Fresnedo, Óscar"

Now showing items 1-20 of 36

    • A Rank-Constrained Coordinate Ascent Approach to Hybrid Precoding for the Downlink of Wideband Massive (MIMO) Systems 

      González-Coma, José P.; Fresnedo, Óscar; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2023-12)
      [Abstract]: An innovative approach to hybrid analog-digital precoding for the downlink of wideband massive MIMO systems is developed. The proposed solution, termed Rank-Constrained Coordinate Ascent (RCCA), starts seeking ...

    • Alternating Minimization for Wideband Multiuser IRS-Aided MIMO Systems Under Imperfect CSI 

      Pérez-Adán, Darian; Joham, Michael; Fresnedo, Óscar; González-Coma, José P.; Castedo, Luis; Utschick, Wolfgang (Institute of Electrical and Electronics Engineers, 2023-11-28)
      [Abstract]: This work focuses on wideband intelligent reflecting surface (IRS)-aided multiuser MIMO systems. One of the major challenges of this scenario is the joint design of the frequency-dependent base station (BS) ...

    • Analog joint source channel coding for wireless communications 

      Fresnedo, Óscar (2014)
      [Abstract] In 1948, the Shannon's work titled "A mathematical theory of communication" completely revolutionized the way to understand the problem of the reliable communications. He showed that any communications system ...

    • Analog joint source-channel coding over MIMO channels 

      Vázquez Araújo, Francisco Javier; Fresnedo, Óscar; Castedo, Luis; Garcia-Frias, Javier (SpringerOpen & European Association for Signal Processing, 2014-02)
      [Abstract]: Analog joint source-channel coding (JSCC) is a communication strategy that does not follow the separation principle of conventional digital systems but has been shown to approach the optimal distortion-cost ...

    • Analog Transmission of Correlated Sources Over BC With Distortion Balancing 

      Suárez-Casal, Pedro; Fresnedo, Óscar; Castedo, Luis; Garcia-Frias, Javier (Institute of Electrical and Electronics Engineers, 2017-11)
      [Abstract]: Analog transmission of correlated information over Gaussian broadcast channels (BCs) using analog joint source- channel coding (JSCC) is addressed. This communication strategy has attractive advantages, such ...

    • Analog Transmission of Correlated Sources Over Fading SIMO Multiple Access Channels 

      Suárez-Casal, Pedro; Fresnedo, Óscar; Castedo, Luis; Garcia-Frias, Javier (Institute of Electrical and Electronics Engineers, 2017-07)
      [Abstract]: Joint source-channel coding for discrete-time analog sources is an appealing transmission approach because of its extremely low delay and complexity. When the users access the channel orthogonally, analog ...

    • Analog Transmission of Spatio-Temporal Correlated Sources Over MAC With Modulo Mappings 

      Suárez-Casal, Pedro; Fresnedo, Óscar; Castedo, Luis (Institute of Electrical and Electronics Engineers, 2018-05)
      [Abstract]: Modulo mappings is an appealing scheme for the analog transmission of spatially correlated discrete-time analog source symbols over multiple access channels. In this letter, we show that the modulo mappings are ...

    • Analog Video Encoding and Quality Evaluation 

      Balsa, José; Fresnedo, Óscar; García-Naya, José A.; Domínguez-Bolaño, Tomás; Castedo, Luis (M D P I AG, 2019-07-23)
      [Abstract] The most widespread analog video encoding systems in the literature are based on the use of the 2D and 3D DCT. These systems use both transformations indistinctly without assessing their suitability. In this ...

    • Analogue joint source-channel coding for multiple input multiple output–orthogonal frequency division multiplexing systems 

      Fresnedo, Óscar; Vázquez Araújo, Francisco Javier; Castedo, Luis; Garcia-Frias, Javier (Wiley, 2016)
      [Abstract]: Analogue joint source-channel coding (JSCC) has been shown to approach the optimal distortion-cost trade-off when transmitting over additive white Gaussian noise channels. In this work, we consider analogue ...

    • 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 ...

    • 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 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 ...

    • Developing cooperative learning and TV-like quizzes to improve students’ motivation in higher education 

      Fresnedo, Óscar; Castro-Castro, Paula-María; Dapena, Adriana; Laport, Francisco (IEEE, 2021-11-24)
      [Abstract]: In this work, we present an instructional methodology which combines the use of Cooperative Learning (CL) and Team Game Tournaments (TGT) for the design of motivating learning activities in higher education. ...

    • Educational graphic tool for teaching fundamentals of digital image representation 

      Fresnedo, Óscar; Laport, Francisco; Castro-Castro, Paula-María; Dapena, Adriana (Wiley, 2021-11)
      [Abstract]: In the last few decades, different teaching methodologies have been proposed to promote more active learning of students. However, it is still essential to understand the practical implications of the theoretical ...

    • 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 ...

    • Eye State Identification Based on Discrete Wavelet Transforms 

      Laport, Francisco; Castro-Castro, Paula-María; Dapena, Adriana; Vázquez Araújo, Francisco Javier; Fresnedo, Óscar (MDPI, 2021)
      [Abstract]: We present a prototype to identify eye states from electroencephalography signals captured from one or two channels. The hardware is based on the integration of low-cost components, while the signal processing ...

    • Image Transmission: Analog or Digital? 

      Balsa González, José Francisco; Domínguez-Bolaño, Tomás; Fresnedo, Óscar; García-Naya, José A.; Castedo, Luis (M D P I AG, 2018-09-18)
      [Abstract] Evaluation and comparison of analog and digital wireless transmission systems.

    • Implementación de una suite gráfica para reforzar el aprendizaje en representación de contenido multimedia 

      Fresnedo, Óscar; Laport, Francisco; Castro-Castro, Paula-María; Dapena, Adriana; Vázquez Araújo, Francisco Javier (2019)
      [Resumen]: Las prácticas de las asignaturas en los grados de Ingeniería Informática se diseñan habitualmente para que los estudiantes formulen y construyan la solución a un determinado problema usando algún lenguaje de ...

    • Intelligent Reflective Surfaces for Wireless Networks: An Overview of Applications, Approached Issues, and Open Problems 

      Pérez-Adán, Darian; Fresnedo, Óscar; González-Coma, José P.; Castedo, Luis (MDPI, 2021)
      [Abstract] An intelligent reflective surface (IRS) is a novel and revolutionizing communication technology destined to enable the control of the radio environment. An IRS is a real-time controllable reflectarray with a ...