Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/1257
2016-10-25T08:49:01ZEfficient bit-level design of an on-board digital TV demultiplexer
http://hdl.handle.net/2117/88670
Efficient bit-level design of an on-board digital TV demultiplexer
Sala Álvarez, José; Pagès Zamora, Alba Maria; Vázquez Grau, Gregorio
A bit-level description of the signal processing stage of an on-board integrated VLSI multi-carrier demodulator is presented in this paper, along with a description of the optimization procedure that has been developed for the signal processing functions1. The demultiplexer is capable of handling a varying number of carriers in a 36 MHz bandwidth on the satellite up-link. Its architecture has been optimized at bit-level in a way dependent on the known input signal statistics and carrier distributions allowed by the frequency plan.
2016-07-11T11:00:59ZSala Álvarez, JoséPagès Zamora, Alba MariaVázquez Grau, GregorioA bit-level description of the signal processing stage of an on-board integrated VLSI multi-carrier demodulator is presented in this paper, along with a description of the optimization procedure that has been developed for the signal processing functions1. The demultiplexer is capable of handling a varying number of carriers in a 36 MHz bandwidth on the satellite up-link. Its architecture has been optimized at bit-level in a way dependent on the known input signal statistics and carrier distributions allowed by the frequency plan.A distributed arithmetics architecture for quantization SNR improvement based on LUT recoding
http://hdl.handle.net/2117/88669
A distributed arithmetics architecture for quantization SNR improvement based on LUT recoding
Rubio Fernández, José; Sala Álvarez, José
2016-07-11T10:59:44ZRubio Fernández, JoséSala Álvarez, JoséHISPANET: a digital television/multimedia payload
http://hdl.handle.net/2117/88668
HISPANET: a digital television/multimedia payload
Sala Álvarez, José; Sergio, Calvo; Pagès Zamora, Alba Maria; Vázquez Grau, Gregorio; Riba Sagarra, Jaume
2016-07-11T10:57:26ZSala Álvarez, JoséSergio, CalvoPagès Zamora, Alba MariaVázquez Grau, GregorioRiba Sagarra, JaumeA fast OFDM-CDMA user demultiplexing architecture
http://hdl.handle.net/2117/88665
A fast OFDM-CDMA user demultiplexing architecture
Marti Puig, Pere; Sala Álvarez, José
A fast algorithm based on a butterfly structure is presented that demultiplexes the symbols of a particular type of MC-MA (multi-carrier multiple-access) modulation previously proposed for indoor radio communications. A special transform is used to packetize the different symbols on the down-link such that the code sequences associated with the different symbols are transmitted synchronously at the base station. The input to the FFT bins is defined as a symbol-dependent combination of Walsh-Hadamard codes. We derive a fast architecture that can combine the common redundancy found in the Walsh-Hadamard and the inverse Fourier transform. In the direct implementation, the receiver would compute the IFFT (as in OFDM) before the Walsh-Hadamard transform. The proposed algorithm evaluates both transforms in a single step. A general expression for the butterfly weights is derived and the savings in computational complexity in terms of the frame length is evaluated.
2016-07-11T10:52:18ZMarti Puig, PereSala Álvarez, JoséA fast algorithm based on a butterfly structure is presented that demultiplexes the symbols of a particular type of MC-MA (multi-carrier multiple-access) modulation previously proposed for indoor radio communications. A special transform is used to packetize the different symbols on the down-link such that the code sequences associated with the different symbols are transmitted synchronously at the base station. The input to the FFT bins is defined as a symbol-dependent combination of Walsh-Hadamard codes. We derive a fast architecture that can combine the common redundancy found in the Walsh-Hadamard and the inverse Fourier transform. In the direct implementation, the receiver would compute the IFFT (as in OFDM) before the Walsh-Hadamard transform. The proposed algorithm evaluates both transforms in a single step. A general expression for the butterfly weights is derived and the savings in computational complexity in terms of the frame length is evaluated.Design and implementation of a DVB on-Board multi-carrier demodulator
http://hdl.handle.net/2117/88656
Design and implementation of a DVB on-Board multi-carrier demodulator
Sala Álvarez, José; Pagès Zamora, Alba Maria; Sergio, Calvo; Prat Gomà, Josep Joan
A description of the signal processing stage of an on-board integrated VLSI multi-carrier demodulator at the demultiplexing level is presented, along with a description of the optimization procedure that has been developed for the signal processing functions. The varying adjacent carrier interference and channel noise distribution are modeled to provide the best performing demultiplexing scheme under the given carrier distribution with minimum complexity.
2016-07-11T09:47:15ZSala Álvarez, JoséPagès Zamora, Alba MariaSergio, CalvoPrat Gomà, Josep JoanA description of the signal processing stage of an on-board integrated VLSI multi-carrier demodulator at the demultiplexing level is presented, along with a description of the optimization procedure that has been developed for the signal processing functions. The varying adjacent carrier interference and channel noise distribution are modeled to provide the best performing demultiplexing scheme under the given carrier distribution with minimum complexity.A statistical reference criterion for adaptive filtering
http://hdl.handle.net/2117/88652
A statistical reference criterion for adaptive filtering
Sala Álvarez, José; Vázquez Grau, Gregorio
A cost function for adaptive filtering is proposed, based on the statistical reference criterion. The purpose of this criterion is to enforce a given probability density function at the output of a system. The only aprioristical knowledge utilized is that of the target PDF. This makes it particularly suitable for blind adaptation in the context of arrays in contrast to temporal or spatial reference techniques. Applications that are foreseen are: blind channel equalization, adaptive beamforming for single or multiple signals and source separation. The main goal is blind signal recovery in unfavourable wanted signal-to-inference power ratios.
2016-07-11T09:20:43ZSala Álvarez, JoséVázquez Grau, GregorioA cost function for adaptive filtering is proposed, based on the statistical reference criterion. The purpose of this criterion is to enforce a given probability density function at the output of a system. The only aprioristical knowledge utilized is that of the target PDF. This makes it particularly suitable for blind adaptation in the context of arrays in contrast to temporal or spatial reference techniques. Applications that are foreseen are: blind channel equalization, adaptive beamforming for single or multiple signals and source separation. The main goal is blind signal recovery in unfavourable wanted signal-to-inference power ratios.Adaptive blind equalization and demodulation without channel and signal parameter extraction
http://hdl.handle.net/2117/88649
Adaptive blind equalization and demodulation without channel and signal parameter extraction
Sala Álvarez, José; Vázquez Grau, Gregorio
The problem of filtering a source of known statistics in noise and/or interference of unknown statistics is addressed in this paper. In a general framework, the optimum estimation (detection) of the desired signal requires perfect knowledge of the probability density functions of the interfering signal and usually leads to complex non-linear algorithms. Herein we have restricted ourselves to linear estimators and optimize performance within this subset according to a criterion derived from information-theoretic considerations. For validation purposes, the particular application of blind data demodulation has been considered. Synchronisation, carrier phase rotation and equalization are performed with the same algorithm to force a source of a known pdf at the output of the adaptive system. Performance at low SNR is derived through simulations.
2016-07-11T08:39:13ZSala Álvarez, JoséVázquez Grau, GregorioThe problem of filtering a source of known statistics in noise and/or interference of unknown statistics is addressed in this paper. In a general framework, the optimum estimation (detection) of the desired signal requires perfect knowledge of the probability density functions of the interfering signal and usually leads to complex non-linear algorithms. Herein we have restricted ourselves to linear estimators and optimize performance within this subset according to a criterion derived from information-theoretic considerations. For validation purposes, the particular application of blind data demodulation has been considered. Synchronisation, carrier phase rotation and equalization are performed with the same algorithm to force a source of a known pdf at the output of the adaptive system. Performance at low SNR is derived through simulations.Global beamforming and demodulation for linearly modulated signals
http://hdl.handle.net/2117/88647
Global beamforming and demodulation for linearly modulated signals
Sala Álvarez, José; Vázquez Grau, Gregorio
2016-07-11T08:18:27ZSala Álvarez, JoséVázquez Grau, GregorioSeparation of digital communication signals through joint space-time decorrelation
http://hdl.handle.net/2117/88645
Separation of digital communication signals through joint space-time decorrelation
Sala Álvarez, José; Vázquez Grau, Gregorio
In this paper we derive the optimum linear algorithm for the separation by an array of a given number of cyclostationary signals of the type encountered in digital communications. Spatially and temporally uncorrelated noise is considered at the input to each sensor. It is proved that the optimum signal separator can be expressed as a matrix transfer function in the z-domain. It is intended that this algorithm be used as a benchmark to test the performance of adaptive schemes. Therefore, bounds on the noise estimation covariance are obtained assuming perfect knowledge of the number of sources as well as of their timing and DOA.
2016-07-11T08:02:54ZSala Álvarez, JoséVázquez Grau, GregorioIn this paper we derive the optimum linear algorithm for the separation by an array of a given number of cyclostationary signals of the type encountered in digital communications. Spatially and temporally uncorrelated noise is considered at the input to each sensor. It is proved that the optimum signal separator can be expressed as a matrix transfer function in the z-domain. It is intended that this algorithm be used as a benchmark to test the performance of adaptive schemes. Therefore, bounds on the noise estimation covariance are obtained assuming perfect knowledge of the number of sources as well as of their timing and DOA.Pointing correction in an adaptive array for communications
http://hdl.handle.net/2117/88548
Pointing correction in an adaptive array for communications
Lagunas Hernandez, Miguel A.; Nájar Martón, Montserrat
The authors discuss DSP procedures for pointing correction in adaptive arrays which uses a spatial reference to form the optimum beam (generalized sidelobe canceller, GSLC). The problem of adequate pointing arises from many effects on the aperture and the receiver front-end of every array channel. Component aging, channel mismatching, sensor location, etc., promote steering errors that may produce the rejection of the desired signal. Currently, highly complicated telemetry systems and monopulse radars are used for steering correction. The authors describe the existing alternatives as well as further improvements that can be achieved from the use of temporal references combined with the GSLC beamformer
2016-07-06T13:06:23ZLagunas Hernandez, Miguel A.Nájar Martón, MontserratThe authors discuss DSP procedures for pointing correction in adaptive arrays which uses a spatial reference to form the optimum beam (generalized sidelobe canceller, GSLC). The problem of adequate pointing arises from many effects on the aperture and the receiver front-end of every array channel. Component aging, channel mismatching, sensor location, etc., promote steering errors that may produce the rejection of the desired signal. Currently, highly complicated telemetry systems and monopulse radars are used for steering correction. The authors describe the existing alternatives as well as further improvements that can be achieved from the use of temporal references combined with the GSLC beamformer