Medina Acosta, Gerardo Agni
Total activity: 7
Research group
CMC - Control, Monitoring and Communications
Department
Department of Signal Theory and Communications
E-mail
gerardo.agni.medinaestudiant.upc.edu
Contact details
UPC directory Open in new window

Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 7 of 7 results
  • An opportunistic cognitive radio communication through the exploitation of the small-scale fading mechanisms of the LTE mobile channel

     Medina Acosta, Gerardo Agni; Delgado Penin, Jose A.; Haneda, Katsuyuki
    Eurasip journal on wireless communication and networking
    Date of publication: 2013
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In recent years, the cognitive radio technology has attracted the attention of all the players in the telecommunication field (i.e., researchers, industry, service providers, and regulatory agencies) as a way of facing the spectrum scarcity. In this regard, and after having reviewed the vast activity linked to this concept it is quite easy to realize that the spectrum sensing task turns out to be the keystone of this technology. However, nowadays it is still unclear which is (are) going to be the globally recommended technique(s) for carrying out this procedure. So, and aiming at finding an alternative to the technical impediments behind the spectrum sensing task, this research work proposes that the advanced knowledge that is already being collected at the modern primary networks be used in benefit of the cognitive radios. Here, the 3GPP LTE network has been adopted as the primary system providing the information that the cognitive radio transceiver will be using for co-transmitting opportunistically (i.e., at specific moments) through the licensed radio resources, being the secondary access based on a novel model which proposes to overlay the secondary transmission whenever extreme channel conditions be found in the radio link of a particular primary user.

  • Access to the full text
    On the reusage of primary radio resources through the exploitation of the spatiotemporal robustness of the MIMO transmissions  Open access

     Medina Acosta, Gerardo Agni; Delgado Penin, Jose A.
    Journal of Electrical and Computer Engineering
    Date of publication: 2012-09-20
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The spatiotemporal robustness of the MIMO transmissions is exploited aiming at inducing opportunistic secondary communications on the primary radio resources. The proposed model makes use of the smallest singular values and the Extreme Value Theory for characterizing the robustness of the MIMO systems, having always the premise of preventing significant degradations in the performance of the primary communications, while at the same time an attractive number of potential opportunities for secondary are intended to be offered. So, the idea behind the suggested scheme consists in reusing the information that is already available within the primary MIMO networks aiming at cotransmitting opportunistically in a clever manner, which at the end will allow us to make a much more efficient use of both the natural and technical resources.

  • Access to the full text
    On the feasibility of a channel-dependent scheduling for the SC-FDMA in 3GPP-LTE (mobile environment) based on a prioritized-bifacet Hungarian method  Open access

     Medina Acosta, Gerardo Agni; Delgado Penin, Jose A.
    Eurasip journal on wireless communication and networking
    Date of publication: 2011-08-19
    Journal article

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    We propose a methodology based on the prioritization and opportunistic reuse of the optimization algorithm known as Hungarian method for the feasible implementation of a channel-dependent scheduler in the long-term evolution uplink (single carrier frequency division multiple access system). This proposal aims to offer a solution to the third generation system’s constraint of allocating only adjacent subcarriers, by providing an optimal resource allotment under a fairness scheme. A multiuser mobile environment following the third generation partnership project TS 45.005v9.3.0/25.943v9.0.0 was also implemented for evaluating the scheduler’s performance. From the results, it was possible to examine the channel frequency response for all users (four user equipments) along the whole bandwidth, to visualize the dynamic resource allocation for each of the 10,000 channel realizations considered, to generate the statistical distribution and cumulative distribution functions of the obtained global costs, as well as to evaluate the system’s performance once the proposed algorithm was embedded. Comparing and emphasizing the benefits of utilizing the proposed dynamic allotment instead of the classic static-scheduling and other existent methods.

  • Opportunistic communication (cognitive radio) over primary discarded subchannels by applying a double power distribution

     Medina Acosta, Gerardo Agni; Delgado Penin, Jose A.
    International journal of digital multimedia broadcasting
    Date of publication: 2010-05-12
    Journal article

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Low priority communication (cognitive radio) over primary subchannels by applying a double power distribution

     Medina Acosta, Gerardo Agni; Delgado Penin, Jose A.
    International Symposium on Wireless Personal Multimedia Communications
    Presentation's date: 2009-09-10
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In this article, the proposal to establish a simultaneous cognitive radio communication based on a subdistribution of power made over discovered unselected subchannels identified by an initially optimal power allotment for a primary user is shown. The aim of this work is to show the possibility of introducing a low priority (secondary) communication into a single user (licensed) transmission where the total power constraint is shared. The analysis of the proposed transmission scheme was performed by considering eight independent subchannels affected by Rayleigh fading, over 2000 channel realizations, and three different signal-to-noise ratios (4dB, 8dB, and 15dB). From the system evaluation it was possible to find the optimal power allotment for the primary user, the subdistribution of power for the secondary user, as well as the attenuation and the capacity per subchannel for every channel realization. Moreover, the PDF of the total capacities and their averages were obtained as a complementary result.

  • Access to the full text
    Método de detección de usuarios primarios utilizando una descomposición wavelet  Open access

     Medina Acosta, Gerardo Agni; Delgado Penin, Jose A.
    Simposium Nacional de la Unión Científica Internacional de Radio
    Presentation's date: 2009-09-17
    Presentation of work at congresses

    Read the abstract Read the abstract Access to the full text Access to the full text Open in new window  Share Reference managers Reference managers Open in new window

    The sensing function is one of the most important features of cognitive radios since a reliable detection of available spectrum ensuring non-interference to licensed users is necessary to initiate a lower priority communication. In this paper, the proposal of a physical layer sensing method using the multiple-level wavelet decomposition analysis for the detection of primary users is presented. The proposed scheme consists of four stages (sampling, multiple-level decomposition analysis, coefficients analysis and evaluation criterion), where the energy percentage through the decomposed levels is proposed as a metric to determine if there is a high priority user present on the channel or not. For simulation purposes different input signals involving the presence/absence of a primary user as well as variations in the SNR were considered in order to evaluate the model.

  • Análisis comparativo de la implementación de un sistema de transmisión digital con parámetros definidos en la capa física del estándar IEEE 802.16 utilizando MATLAB y SIMULINK

     Medina Acosta, Gerardo Agni; Cuevas, J L; Delgado Penin, Jose A.
    Simposium Nacional de la Unión Científica Internacional de Radio
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window