Now showing items 21-40 of 57

    • Interference modelling of IMT-A Systems in LA-TDD Scenarios 

      Puig Arbat, Gemma (Universitat Politècnica de Catalunya, 2008-06-04)
      Master thesis
      Open Access
      Orthogonal Frequency Division Multiple Access( OFDMA) and Single Carrier Frequency Division Multiple Access( SC-FDMA), the access techniques used in DL and UL respectively in UTRAN LTE, are strong candidates also for ...
    • Low cost OFDM based transmitter for underwater acoustic communications 

      Sarriá Gandul, David; Pallarés Valls, Oriol; Río Fernandez, Joaquín del; Manuel Lázaro, Antonio (2013)
      Conference report
      Open Access
      On this work a low cost OFDM transmitter for underwater sensor networks is presented. The transmitter is based on a low power microcontroller that governs a DDS in order to generate the output data -OFDM symbols- avoiding ...
    • LTE performance evaluation with realistic channel quality indicator feedback 

      Churchman Barata, Mathew William (Universitat Politècnica de Catalunya, 2011-04-29)
      Master thesis
      Open Access
      In the context of mobile communications, the availability of new services and mobile applications along with the constant evolution in terminals run up the need of higher data rates. In order to fulfill such expectations, ...
    • Maximización de la eficiencia energética de amplificadores de potencia mediante valores óptimos de clipping para senyales OFDM 

      Falcon Romero, Judit; Díaz Pérez, Iban (Universitat Politècnica de Catalunya, 2008-07-25)
      Master thesis (pre-Bologna period)
      Open Access
      Este trabajo de fin de carrera está orientado a la mejora de la linealidad y eficiencia energética de amplificadores de potencia a través de la combinación de técnicas de clipping y linealización mediante predistorsión ...
    • Multi-stream transmission in MIMO-FBMC systems 

      Caus López, Marius; Pérez Neira, Ana Isabel (Institute of Electrical and Electronics Engineers (IEEE), 2013)
      Conference report
      Restricted access - publisher's policy
      This paper addresses the design of MIMO precoding and decoding techniques for the filter bank multicarrier (FBMC) modulation. Existing solutions give satisfactory performance in scenarios with high coherence bandwidth ...
    • Multiple user connection strategies for optical OFDM networks 

      Martín Medina, Saúl (Universitat Politècnica de Catalunya, 2011-12-23)
      Master thesis
      Open Access
      Orthogonal Frequency Division Multiplexing, OFDM, is an emerging modulation technique which is now used in most broadband wired and wireless communication systems. Its narrow multi-carrier nature provides a very effective ...
    • Multipolling and OFDMA Reservation Protocol for IEEE 802.11 Networks 

      Pérez Díaz de Cerio, David; Valenzuela González, José Luis; Villares Piera, Nemesio Javier (Institute of Electrical and Electronic Engineers, 2009)
      Conference report
      Open Access
      This paper presents an efficient multipolling scheme that improves the IEEE 802.11 MAC protocol efficiency and does not suffer from the hidden terminal problem or inefficient channel usage problems. To design an efficient ...
    • Next-generation optical access networks based on Orthogonal Frequency Division Multiplexing 

      De las Heras Mandome, Marçal (Universitat Politècnica de Catalunya, 2011-09-30)
      Master thesis
      Open Access
      Orthogonal Frequency Division Multiplexing (OFDM) is a robust modulation and multiplexing format which is at the base of many present communication standards. The interest of the OFDM application in optical fiber deployments ...
    • OFDM and FBMC Performance Comparison for Multistream MIMO Systems 

      Estella, Iñaki; Pascual Iserte, Antonio; Payaró Llisterri, Miquel (2010-06)
      Conference lecture
      Open Access
    • Optimal distributed frequency planning for OFDMA femtocell networks 

      Bezerra Rodrigues, Emanuel; Casadevall Palacio, Fernando José (Institute of Electrical and Electronics Engineers (IEEE), 2013)
      Conference report
      Restricted access - publisher's policy
      Femtocell networks have gained momentum due to their important benefits, such as improved indoor coverage, higher areal spectral efficiency, enhanced signal quality, among others. Those benefits are only achievable if ...
    • Optimization of optical OFDM transmission systems 

      Romero Vidal, Cristóbal Manuel (Universitat Politècnica de Catalunya, 2012-01-25)
      Master thesis
      Open Access
      Orthogonal frequency division multiplexing (OFDM) is a well-known modulation technique which is used in broadband wired and wireless communication systems, such as standard 802.11a/b/g/n, digital video broadcasting television ...
    • Optimum carrier to signal power ratio for remote heterodyne DD-OFDM in PONs 

      Cano Valadéz, Iván Nicolás; Santos Blanco, M. Concepción; Prat Gomà, Josep Joan (2013-07)
      Article
      Restricted access - publisher's policy
      The carrier to signal power ratio (CSPR) in a directdetection optical orthogonal frequency division multiplexing (OFDM) system based on remote heterodyne scheme is optimized in a passive optical network (PON) downlink. ...
    • Optimum power allocation and bit loading for BICM systems 

      Matas Navarro, David; Lamarca Orozco, M. Meritxell (2010-07-01)
      Article
      Open Access
      This paper introduces a joint bit loading and power allocation algorithm for systems combining bit-interleaved coded modulation (BICM) with multicarrier transmission. The proposed algorithm maximizes the mutual information, ...
    • Overview on Crest Fator Reduction Techniques to Reduce Peak-to-Average Power Ratio in OFDM Signals 

      López Caro, Alberto (Universitat Politècnica de Catalunya, 2009-06-22)
      Master thesis (pre-Bologna period)
      Open Access
    • PAPR reduction in OFDM systems 

      Revuelto Lorda, Natalia (Universitat Politècnica de Catalunya, 2008-09-18)
      Master thesis
      Open Access
      In the last years wireless communications have experienced a fast growth due to the high mobility that they allow. However, wireless channels have some disadvantages, like multipath fading, that make them difficult to ...
    • Performance degradation of an OFDM-MIMO system with imperfect channel state information at the transmitter 

      Pascual Iserte, Antonio; Pérez Neira, Ana Isabel; Lagunas Hernandez, Miguel A. (2003)
      Conference report
      Open Access
      In this paper we analyze the performance degradation of a communications system combining the Orthogonal Frequency Division Multiplexing (OFDM) modulation with the simultaneous use of an array of antennas at both the ...
    • Performance of a filterBank multiCarrier (FBMC) physical layer in the WiMAX context 

      Ringset, Vidar; Rustad, Helge; Schaich, Frank; Vandermont, Jurgen; Nájar Martón, Montserrat (2010)
      Conference report
      Open Access
      This paper describes some of the outcome of the FP7 project PHYDYAS, whose main objective was to propose a new physical layer that will enable introduction of cognitive radios and dynamic access spectrum management. ...
    • Physical layer evaluation of OFDM-based access networks 

      Cano Valadéz, Iván Nicolás; Santos Blanco, M. Concepción; Prat Gomà, Josep Joan; Krimmel, H.G.; Kavatzikidis, T.; Giacoumidis, E.; Tomkos, Ioannis (IEEE Press. Institute of Electrical and Electronics Engineers, 2011)
      Conference report
      Restricted access - publisher's policy
      In this paper, we present a physical layer parameter optimization of direct-detection optical OFDM techniques at bitrates of 10 Gb/s and 40 Gb/s using an intensity modulation and two types of field modulation transmitte ...
    • Planning optimization software tool for DVB-T and DVB-T2 

      Lema Rosas, María Ángel; Torras López, Evelyn (Universitat Politècnica de Catalunya, 2010-06-25)
      Master thesis
      Open Access
    • Practical bit loading schemes for multi-antenna multi-user wireless OFDM systems 

      Bartolomé Calvo, Diego; Pérez Neira, Ana Isabel (2004)
      Conference report
      Open Access
      This paper deals with practical multi-antenna multiuser OFDM systems. With the additional degrees of freedom of multiple antennas and multiple subcarriers, the performance might be enhanced, but the scheduling complexity ...