Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/1257
Sun, 29 May 2016 06:19:59 GMT2016-05-29T06:19:59ZConstant variance transversal filtering for adaptive channel equalization
http://hdl.handle.net/2117/87429
Constant variance transversal filtering for adaptive channel equalization
Vázquez Grau, Gregorio; Gasull Llampallas, Antoni; Sanchez, J J; Lagunas Hernandez, Miguel A.
Fri, 27 May 2016 12:57:18 GMThttp://hdl.handle.net/2117/874292016-05-27T12:57:18ZVázquez Grau, GregorioGasull Llampallas, AntoniSanchez, J JLagunas Hernandez, Miguel A.Preemption and QoS management algorithms for coordinated and uncoordinated base stations
http://hdl.handle.net/2117/87385
Preemption and QoS management algorithms for coordinated and uncoordinated base stations
Muñoz Medina, Olga; Pascual Iserte, Antonio; Baquero, Pau; Vidal Manzano, José
This paper addresses the problem of resource allocation and quality
of service (QoS) management in a downlink communication system
where the users are allowed to be attached to and receive data
from one or several cooperating base stations (BSs) under orthogonal
frequency division multiple access (OFDMA). Under the assumption
that only information regarding the link path loss is available
at each transmitter, the problem of power and bandwidth allocation
to minimize transmission power subject to minimum rate (i.e., QoS)
constraints is written as a convex optimization problem. Considering
that the transmission power per BS is limited, the Lagrange
multipliers of the optimization problem are exploited either to ef-
ficiently identify which are the candidates to be preempted whenever
unaffordable power consumption arises, or to relax the target
rate constraints for the ongoing connections. In the second case,
the Lagrange multipliers are used in combination with the NewtonRaphson
algorithm to adjust the QoS of the users in the system according
to the available BS power.
Thu, 26 May 2016 14:28:56 GMThttp://hdl.handle.net/2117/873852016-05-26T14:28:56ZMuñoz Medina, OlgaPascual Iserte, AntonioBaquero, PauVidal Manzano, JoséThis paper addresses the problem of resource allocation and quality
of service (QoS) management in a downlink communication system
where the users are allowed to be attached to and receive data
from one or several cooperating base stations (BSs) under orthogonal
frequency division multiple access (OFDMA). Under the assumption
that only information regarding the link path loss is available
at each transmitter, the problem of power and bandwidth allocation
to minimize transmission power subject to minimum rate (i.e., QoS)
constraints is written as a convex optimization problem. Considering
that the transmission power per BS is limited, the Lagrange
multipliers of the optimization problem are exploited either to ef-
ficiently identify which are the candidates to be preempted whenever
unaffordable power consumption arises, or to relax the target
rate constraints for the ongoing connections. In the second case,
the Lagrange multipliers are used in combination with the NewtonRaphson
algorithm to adjust the QoS of the users in the system according
to the available BS power.Inclusion of gradient-based schemes in high resolution method
http://hdl.handle.net/2117/87368
Inclusion of gradient-based schemes in high resolution method
Vázquez Grau, Gregorio; Vallverdú Bayés, Francesc
This paper deals with the inclusion of adaptive schemes in high-resolution methods. Past works refer gradient and conjugated gradient approaches of Pisarenko’s spectral line decomposition method for sinusoidal in white noise modelling. The proposal is more general in the objective definition. It is well known that it is possible to generate a complete family of spectral estimators from a Normalized Maximum Likelihood Method, with a structure of power Rayleigh quotien.
Thu, 26 May 2016 13:46:26 GMThttp://hdl.handle.net/2117/873682016-05-26T13:46:26ZVázquez Grau, GregorioVallverdú Bayés, FrancescThis paper deals with the inclusion of adaptive schemes in high-resolution methods. Past works refer gradient and conjugated gradient approaches of Pisarenko’s spectral line decomposition method for sinusoidal in white noise modelling. The proposal is more general in the objective definition. It is well known that it is possible to generate a complete family of spectral estimators from a Normalized Maximum Likelihood Method, with a structure of power Rayleigh quotien.Use of the available information for adequate step-size actualization
http://hdl.handle.net/2117/87366
Use of the available information for adequate step-size actualization
Vázquez Grau, Gregorio; Gasull Llampallas, Antoni
This paper deals with the use of the available information for the update of the step-size in gradient-based adaptive methods. Several proposals are made and due to the relatively high computational cost, more efficient frequency domain versions are studied. Unscontrained and constrained mininum mean square error algorithms are both considered.
Thu, 26 May 2016 13:35:52 GMThttp://hdl.handle.net/2117/873662016-05-26T13:35:52ZVázquez Grau, GregorioGasull Llampallas, AntoniThis paper deals with the use of the available information for the update of the step-size in gradient-based adaptive methods. Several proposals are made and due to the relatively high computational cost, more efficient frequency domain versions are studied. Unscontrained and constrained mininum mean square error algorithms are both considered.Design and implementation of a 2048FFT capture spectrum analyzer
http://hdl.handle.net/2117/87362
Design and implementation of a 2048FFT capture spectrum analyzer
Vázquez Grau, Gregorio
This paper describes the hardware implementation of a digital spectrum analyzer which, by using a capture process of the signal under processing, performs some non parametric signal processing techniques. All the possibilities to implement a spectrum analyzer will arise to a bank filter analysis approach. When the instrument works as an off-line processor, the bank filter can be a linear transform, which results in a FFT as concerns with the analysis of the power density content of the data sample.
Thus the FFT processor can be viewed as a set of equispaced filters with non-ideal cut-off and secondary lobes but optimum to analyze pure tones in a white noise environment.
Thu, 26 May 2016 13:02:40 GMThttp://hdl.handle.net/2117/873622016-05-26T13:02:40ZVázquez Grau, GregorioThis paper describes the hardware implementation of a digital spectrum analyzer which, by using a capture process of the signal under processing, performs some non parametric signal processing techniques. All the possibilities to implement a spectrum analyzer will arise to a bank filter analysis approach. When the instrument works as an off-line processor, the bank filter can be a linear transform, which results in a FFT as concerns with the analysis of the power density content of the data sample.
Thus the FFT processor can be viewed as a set of equispaced filters with non-ideal cut-off and secondary lobes but optimum to analyze pure tones in a white noise environment.Bit-slice implementation of a linear predictive vocoder
http://hdl.handle.net/2117/87361
Bit-slice implementation of a linear predictive vocoder
Vázquez Grau, Gregorio; Gasull Llampallas, Antoni
A digital 16-bit high-speed general-purpose signal-processor is shown. The main objective has been the implementation of a linear predictive vocoder for obtaining real-time speech compression.
For real-time digital speech processing, fast devices and special procedure designs are needed. Thus, in obtaining high speed processors, multi-data paths, parallel and pipeline arquitectures have been adopted.
Thu, 26 May 2016 12:56:15 GMThttp://hdl.handle.net/2117/873612016-05-26T12:56:15ZVázquez Grau, GregorioGasull Llampallas, AntoniA digital 16-bit high-speed general-purpose signal-processor is shown. The main objective has been the implementation of a linear predictive vocoder for obtaining real-time speech compression.
For real-time digital speech processing, fast devices and special procedure designs are needed. Thus, in obtaining high speed processors, multi-data paths, parallel and pipeline arquitectures have been adopted.Simultaneous wireless information and power transfer in multiuser MIMO systems
http://hdl.handle.net/2117/86262
Simultaneous wireless information and power transfer in multiuser MIMO systems
Rubio López, Javier; Pascual Iserte, Antonio
In this paper, we focus on a broadcast multiuser
multiple-input multiple-output (MIMO) system in a network
with short links. In this scenario we consider that some
terminals harvest power and, thus, recharge their batteries,
through wireless power transfer from the transmitter while
others are simultaneously being served with data transmission.
We assume that the nodes are battery powered devices and,
consequently, such solution provides a convenient energy supply.
The sum-rate for the users being served with data is considered
as the optimization policy where power harvesting per user
constraints are taken into account. We provide the optimal
structure of the resulting transmit covariance matrices and
precoders for the users in the general case (i.e., in scenarios
where both types of nodes are present in the network) and we
also study the case where only harvesting nodes are to be served.
Finally, we analyze and characterize the fundamental tradeoff
between the data transmission sum-rate and the powers
harvested by the network nodes using the concept of the rateenergy
(R-E) region.
Wed, 27 Apr 2016 13:16:43 GMThttp://hdl.handle.net/2117/862622016-04-27T13:16:43ZRubio López, JavierPascual Iserte, AntonioIn this paper, we focus on a broadcast multiuser
multiple-input multiple-output (MIMO) system in a network
with short links. In this scenario we consider that some
terminals harvest power and, thus, recharge their batteries,
through wireless power transfer from the transmitter while
others are simultaneously being served with data transmission.
We assume that the nodes are battery powered devices and,
consequently, such solution provides a convenient energy supply.
The sum-rate for the users being served with data is considered
as the optimization policy where power harvesting per user
constraints are taken into account. We provide the optimal
structure of the resulting transmit covariance matrices and
precoders for the users in the general case (i.e., in scenarios
where both types of nodes are present in the network) and we
also study the case where only harvesting nodes are to be served.
Finally, we analyze and characterize the fundamental tradeoff
between the data transmission sum-rate and the powers
harvested by the network nodes using the concept of the rateenergy
(R-E) region.Energy-aware broadcast MU-MIMO precoder design with imperfect battery knowledge
http://hdl.handle.net/2117/86261
Energy-aware broadcast MU-MIMO precoder design with imperfect battery knowledge
Rubio López, Javier; Pascual Iserte, Antonio
This paper addresses the problem of precoder
design in a MIMO broadcast scenario where the terminals
are battery-powered devices provided with energy harvesting
capabilities. Models for the power consumption of the RF and
decoding stages are discussed and included in the design of
the proposed scheme. Sum-rate maximization is taken as optimization
policy and energy-related constraints are considered
to increase the duration of the batteries and, thus, the network
lifetime. Simulation results show that not only the usage of
battery is improved when compared with other traditional
allocation policies, but also the average data rate is enhanced.
Wed, 27 Apr 2016 13:13:19 GMThttp://hdl.handle.net/2117/862612016-04-27T13:13:19ZRubio López, JavierPascual Iserte, AntonioThis paper addresses the problem of precoder
design in a MIMO broadcast scenario where the terminals
are battery-powered devices provided with energy harvesting
capabilities. Models for the power consumption of the RF and
decoding stages are discussed and included in the design of
the proposed scheme. Sum-rate maximization is taken as optimization
policy and energy-related constraints are considered
to increase the duration of the batteries and, thus, the network
lifetime. Simulation results show that not only the usage of
battery is improved when compared with other traditional
allocation policies, but also the average data rate is enhanced.Filtrado transversal adaptativo de varianza constante para la ecualización de canal
http://hdl.handle.net/2117/86209
Filtrado transversal adaptativo de varianza constante para la ecualización de canal
Vázquez Grau, Gregorio; Gasull Llampallas, Antoni; Sánchez Umbría, Juan; Oliveras Vergés, Albert
This paper describes the problem of lineal filtering of noisy data under a Maximum Likelihood objective. In this sense, the paper shows that a weighted square error cost function deals and it is necessary to weight the filtering error sequence by a factor that, basically, depends the probability density function of the error sequence and on its first derivate. As it is well known, this information used to be not available and other proposals must be made. For this purpose, going around this problem, the paper discusses the design of this weighting factor for including sorne kind of data-selection mechanism for the final filter weight-vector solution design. The underlying of the proposal is the development of a recursive algorithm in such a way that for any measure or observation, its associated
Tue, 26 Apr 2016 14:37:29 GMThttp://hdl.handle.net/2117/862092016-04-26T14:37:29ZVázquez Grau, GregorioGasull Llampallas, AntoniSánchez Umbría, JuanOliveras Vergés, AlbertThis paper describes the problem of lineal filtering of noisy data under a Maximum Likelihood objective. In this sense, the paper shows that a weighted square error cost function deals and it is necessary to weight the filtering error sequence by a factor that, basically, depends the probability density function of the error sequence and on its first derivate. As it is well known, this information used to be not available and other proposals must be made. For this purpose, going around this problem, the paper discusses the design of this weighting factor for including sorne kind of data-selection mechanism for the final filter weight-vector solution design. The underlying of the proposal is the development of a recursive algorithm in such a way that for any measure or observation, its associatedAdaptive spectrum estimation with linear constrains
http://hdl.handle.net/2117/86201
Adaptive spectrum estimation with linear constrains
Vázquez Grau, Gregorio; Vallverdú Bayés, Francesc
A general constrained adaptive metbod is developed to be applied to the spectral estimation problem. The method presented can be used in a wide range of situatious, this is, we can get different estimators wíth it. The algorithm is formulated in a varíational approach context,and tbe non linear system obtained is solved with a constrained adaptive method applied to a digitized version of the spedrum. The set of constraínts is considered to be a set of known correlation values, and they can be located in non consecutíve lags. A generalization of the method is done, so it can be used in a rnu lt idimensional framework. As an example, a bidimensional ma.ximum entropy spectrum is presented.
Tue, 26 Apr 2016 13:05:44 GMThttp://hdl.handle.net/2117/862012016-04-26T13:05:44ZVázquez Grau, GregorioVallverdú Bayés, FrancescA general constrained adaptive metbod is developed to be applied to the spectral estimation problem. The method presented can be used in a wide range of situatious, this is, we can get different estimators wíth it. The algorithm is formulated in a varíational approach context,and tbe non linear system obtained is solved with a constrained adaptive method applied to a digitized version of the spedrum. The set of constraínts is considered to be a set of known correlation values, and they can be located in non consecutíve lags. A generalization of the method is done, so it can be used in a rnu lt idimensional framework. As an example, a bidimensional ma.ximum entropy spectrum is presented.