Podcasts about aqpa

"Tenemos dos tareas importantes que reconciliar; primero, recordar y honrar tanto la memoria como el espíritu de aquellos que perdieron la vida, y segundo, celebrar la vida y la música que representa este teatro histórico”, dijo Sting al confirmar su concierto solidario para la reapertura de la misma sala donde en 1970 se presentó con The Police. Pete Doherty, Youssou Ndour y Marianne Faithfull, entre otros artistas, forman parte de la cartelera que anuncia los próximos espectáculos cuyas localidades quedan rápidamente agotadas apenas salen a la venta. Sobrevivientes, familiares de víctimas e integrantes de Eagles of Death Metal –ellos también sobrevivientes– fueron invitados a los homenajes de este fin de semana en el Bataclán. La banda californiana ofrecía su espectáculo en el lugar cuando se desató el horror del 13-N. “El día que París se apagó”, producción de Contenidos, Radio Nacional, reúne audios grabados durante la masacre, testimonios posteriores y declaraciones del presidente Francois Hollande, quien atribuyó lo sucedido a “un acto de guerra cometido por un ejército terrorista, el Daesh, un ejército yihadista”. Entrada la noche del viernes 13 de noviembre de 2015, la ciudad de las luces repentinamente atrajo la atención del mundo, con diferencias de pocos minutos padeció sucesivos atentados contra diversos blancos, encadenados ataques suicidas, tomas de rehenes, explosiones y disparos a mansalva que dejaron el saldo de 127 muertos, centenares de heridos y un país, un continente en estado de pánico. El mayor impacto se produjo dentro de este espacio cultural, ahora “renacido” según anuncian sus dueños, cercano a la redacción del semanario satírico francés Charlie Hebdo. Allí, meses antes, doce personas habían sido ejecutadas por un grupo luego reivindicado por Al-Qaeda en la Península Arábiga (AQPA).      

Speaker: Dr. S. Dey Abstract: In this talk, we consider a wideband spectrum sharing system where a secondary user can share a number of orthogonal frequency bands each licensed to a distinct primary user. We address the problem of optimum secondary transmit power allocation for its ergodic capacity maximization subject to an average sum (across the bands) transmit power constraint and individual average interference constraints on the primary users. The major contribution of our work lies in considering quantized channel state information (CSI) (for the vector channel space consisting of all secondary-to-secondary and secondary-to-primary channels) at the secondary transmitter as opposed to the prevalent assumption of full CSI in most existing work.It is assumed that a band manager or a cognitive radio service provider has access to the full CSI information from the secondary and primary receivers and designs (offline) an optimal power codebook based on the statistical information(channel distributions) of the channels and feeds back the index of the codebook to the secondary transmitter for every channel realization in real-time, via a delay-free noiseless limited feedback channel. A modified Generalized Lloyds-type algorithm (GLA) is designed for deriving the optimal power codebook,which is proved to be globally convergent and empirically consistent. An approximate quantized power allocation (AQPA) algorithm is presented,that performs very close to its GLA based counterpart for large number of feedback bits and is significantly faster.We also present an extension of the modified GLA based quantized power codebook design algorithm for the case when the feedback channel is noisy. Numerical studies illustrate that with only 3-4 bits of feedback, the modified GLA based algorithms provide secondary ergodic capacity very close to that achieved by full CSI and with only as little as 4 bits of feedback, AQPA provides a comparable performance,thus making it an attractive choice for practical implementation.Various open problems and future research directions will also be discussed.

Speaker: Dr. S. Dey Abstract: In this talk, we consider a wideband spectrum sharing system where a secondary user can share a number of orthogonal frequency bands each licensed to a distinct primary user. We address the problem of optimum secondary transmit power allocation for its ergodic capacity maximization subject to an average sum (across the bands) transmit power constraint and individual average interference constraints on the primary users. The major contribution of our work lies in considering quantized channel state information (CSI) (for the vector channel space consisting of all secondary-to-secondary and secondary-to-primary channels) at the secondary transmitter as opposed to the prevalent assumption of full CSI in most existing work.It is assumed that a band manager or a cognitive radio service provider has access to the full CSI information from the secondary and primary receivers and designs (offline) an optimal power codebook based on the statistical information(channel distributions) of the channels and feeds back the index of the codebook to the secondary transmitter for every channel realization in real-time, via a delay-free noiseless limited feedback channel. A modified Generalized Lloyds-type algorithm (GLA) is designed for deriving the optimal power codebook,which is proved to be globally convergent and empirically consistent. An approximate quantized power allocation (AQPA) algorithm is presented,that performs very close to its GLA based counterpart for large number of feedback bits and is significantly faster.We also present an extension of the modified GLA based quantized power codebook design algorithm for the case when the feedback channel is noisy. Numerical studies illustrate that with only 3-4 bits of feedback, the modified GLA based algorithms provide secondary ergodic capacity very close to that achieved by full CSI and with only as little as 4 bits of feedback, AQPA provides a comparable performance,thus making it an attractive choice for practical implementation.Various open problems and future research directions will also be discussed.