Now showing items 1-20 of 43

  • Adaptive sampling for fast sparsity pattern recovery 

    Ramírez Javega, Francisco; Matas Navarro, David; Lamarca Orozco, M. Meritxell (2011)
    Conference report
    Open Access
    In this paper we propose a low complexity adaptive algorithm for lossless compressive sampling and reconstruction of sparse signals. Consider a sparse non-negative real signal x containing only 𝑘 << 𝑛 non-zero values. ...
  • ADC Quantization Requirements 

    Riba Sagarra, Jaume; Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier (2000-06)
    External research report
    Open Access
    In this document, we analyze the impact of the quantization at the input of the demultiplexer. The required number of bits of the Analog-to-Digital-Converter (ADC) is obtained, along with the corresponding quantization losses.
  • Analog joint source channel coding using space-filling curves and MMSE decoding 

    Hu, Yichuan; García Frías, Javier; Lamarca Orozco, M. Meritxell (2009)
    Conference report
    Open Access
    We investigate the performance of a discrete-time all-analog-processing joint sourcechannel coding system for the transmission of i.i.d. Gaussian and Laplacian sources over AWGN channels. In the encoder, two samples of ...
  • Analysis of LDPC code syndrome entropy based on subgraphs 

    Matas Navarro, David; Lamarca Orozco, M. Meritxell (Institute of Electrical and Electronics Engineers (IEEE), 2016)
    Conference report
    Restricted access - publisher's policy
    We propose a method to bound the syndrome entropy of linear block codes from their factor graph representation. It is specially suited for sparse graphs such as those of low density parity check codes. It is based on the ...
  • A non-linear channel code for covert communications 

    Lamarca Orozco, M. Meritxell; Matas Navarro, David (Institute of Electrical and Electronics Engineers (IEEE), 2019)
    Conference lecture
    Restricted access - publisher's policy
    This paper presents an explicit channel code design for covert communications in the Binary Symmetric Channel. The proposed architecture is composed of the serial concatenation of a linear code and a graph-based non-linear ...
  • ANTARES Project (Phase B). Multiple acces scheme definition. Diverse trade-offs analysis for TDMA and CDMA 

    Villares Piera, Nemesio Javier; Font Segura, Josep; Matas Navarro, David; Ramírez Javega, Francisco; Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio (2010-03-01)
    External research report
    Restricted access - confidentiality agreement
  • ANTARES Project (Phase B). Multiple acces scheme definition. Spectral efficiency analysis of the MAC techniques considered for the Antares forward and return links 

    Villares Piera, Nemesio Javier; Font Segura, Josep; Matas Navarro, David; Ramírez Javega, Francisco; Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio (2010-07-01)
    External research report
    Restricted access - confidentiality agreement
  • ANTARES Project (Phase B). Multiple acces scheme definition. Successive interference cancellation for A-CDMA 

    Villares Piera, Nemesio Javier; Font Segura, Josep; Matas Navarro, David; Ramírez Javega, Francisco; Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio (2010-05-01)
    External research report
    Restricted access - confidentiality agreement
  • ANTARES Project (Phase B). Multiple access scheme definition. Impact of the aeronautical channel on the MAC techniques considered for the Antares forward and return links 

    Villares Piera, Nemesio Javier; Font Segura, Josep; Lamarca Orozco, M. Meritxell; Matas Navarro, David; Ramírez Javega, Francisco; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio (2010-03-01)
    External research report
    Restricted access - confidentiality agreement
  • ANTARES Project (Phase B). Physical layer definition. Equalization detailed design 

    Villares Piera, Nemesio Javier; Font Segura, Josep; Matas Navarro, David; Ramírez Javega, Francisco; Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio (2010-08-01)
    External research report
    Restricted access - confidentiality agreement
  • ANTARES Project (Phase B). Physical layer definition. Payload carrier synchronization for the Antares TDMA return link 

    Villares Piera, Nemesio Javier; Font Segura, Josep; Matas Navarro, David; Ramírez Javega, Francisco; Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio (2010-08-01)
    External research report
    Restricted access - confidentiality agreement
  • A rain and scintillation Ka-band channel simulator 

    Rodríguez, E; Sala Álvarez, José; Lamarca Orozco, M. Meritxell; López, J. A.; Rey Micolau, Francesc; Riba Sagarra, Jaume; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier; Jalón, A (ESA, 2008)
    Conference report
    Open Access
    This paper describes the implementation of a Ka-band satellite channel simulator with emphasis on the synthesis of scintillation processes. The problem becomes one of generating a given probability density function, ...
  • Asymptotic MAP upper bounds for LDPC codes 

    Matas Navarro, David; Lamarca Orozco, M. Meritxell (Institute of Electrical and Electronics Engineers (IEEE), 2016)
    Conference report
    Restricted access - publisher's policy
    This paper aims at computing tight upper bounds for the maximum a posteriori threshold of low-density parity check codes in the asymptotic blocklength regime for the transmission over binary-input memoryless symmetricoutput ...
  • Binary graphs and message passing strategies for compressed sensing in the noiseless setting 

    Ramírez Javega, Francisco; Lamarca Orozco, M. Meritxell; Villares Piera, Nemesio Javier (Institute of Electrical and Electronics Engineers (IEEE), 2012)
    Conference report
    Restricted access - publisher's policy
    We propose a scheme for Compressed Sensing in the noiseless setting that reconstructs the original signal operating on a binary graph where the samples are obtained sequentially. The proposed scheme has an affordable ...
  • Blind equalization based on spatial and temporal diversity in block coded modulations 

    Rey Micolau, Francesc; Lamarca Orozco, M. Meritxell; Vázquez Grau, Gregorio (Institute of Electrical and Electronics Engineers (IEEE), 1998)
    Conference report
    Open Access
    Linear block codes can be applied in spatial and/or temporal diversity receivers in order to develop high performance schemes for blind equalization in mobile communications. The proposed technique uses the structure of ...
  • Channel estimation for transform modulations in mobile communications 

    Lamarca Orozco, M. Meritxell; Vázquez Grau, Gregorio (1996)
    Conference report
    Open Access
    This paper deals with data-aided channel estimation in systems using OFDM modulation. We formulate a pilot symbol-based channel estimator and compare it with the pilot-tone one proposed in [1]. Although this paper focuses ...
  • D1. Estudio de códigos PN para mejorar el ensanchado y la eficiencia espectral del sistema CDMA síncrono y asíncrono 

    Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier (2008-11-10)
    External research report
    Restricted access - confidentiality agreement
  • D2. Estructuras de detector multiusuario para CDMA síncrono y asíncrono 

    Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier (2008-11-10)
    External research report
    Restricted access - confidentiality agreement
  • D3. Sincronización robusta de frecuencia y fase para M-PSK sobre CDMA 

    Lamarca Orozco, M. Meritxell; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier (2008-11-10)
    External research report
    Restricted access - confidentiality agreement
  • DA-GLRT burst detection and synchronization based on a chirp-like preamble 

    Rodríguez, E; Lamarca Orozco, M. Meritxell; López Salcedo, José Antonio; Rey Micolau, Francesc; Riba Sagarra, Jaume; Sala Álvarez, José; Vázquez Grau, Gregorio; Villares Piera, Nemesio Javier; Jalón, A (2008)
    Conference report
    Restricted access - publisher's policy
    A specific preamble for the tasks of signal detection and synchronization in burst digital communications is presented. The preamble resembles a chirp signal used in RADAR applications. Its main benefit is that it allows ...