EMULACIÓN EN FPGA DE TECNICA PARA CORRECCION DEL DESEQUILIBRIO I/Q APLICADO EN UN MODULADOR DIGITAL 256-QAM

Sergio Alberto Juárez Cazares, Aldo Bonilla Rodríguez, José Cruz Núñez Pérez

Resumen


Resumen

En este trabajo se presenta la metodología de diseño e implementación de un sistema para corrección del desequilibrio I/Q basado en una tarjeta DSP-FPGA. Este sistema utiliza series de Volterra para modelar el comportamiento no lineal del desequilibrio I/Q. El desempeño del sistema se demuestra utilizando una señal compleja 256-QAM con desequilibrio en fase y amplitud. El sistema desarrollado tiene como característica un bajo costo de implementación y alta flexibilidad del diseño, lo que permite modificaciones o expansiones futuras. Se utiliza la tarjeta de desarrollo Stratix III de Altera para implementación practica y verificación de los resultados experimentales del sistema propuesto. El sistema desarrollado es capaz de corregir el desequilibrio I/Q satisfactoriamente, tanto en fase como en amplitud. Este trabajo puede ser considerado como una alternativa de bajo costo para corregir el desequilibrio I/Q ya que no requiere de algoritmos complejos o equipo de medición adicional.

Palabras Claves: 256-QAM, corrección, desequilibrio, FPGA, modulador.


EMULATION IN FPGA OF TECHNIQUE FOR CORRECTION OF IMBALANCE I/Q APPLIED IN A DIGITAL MODULATOR 256-QAM


Abstract

In this paper the design methodology for a I/Q imbalance correction system is presented based on a DSP-FPGA board. This system employs Volterra series to model the non-linear behavior of the I/Q imbalance. The system performance is verified using a 256-QAM complex signal with phase and amplitude imbalance. The implemented system has the advantage of having low implementation cost and a high design flexibility, which allows for future revisions or enhancement. The Stratix III FPGA board from Altera is employed for the practical implementation and result verification of the system. The developed system can compensate the I/Q imbalance, in amplitude and phase. This work can be considered as a low-cost alternative for I/Q imbalance correction given that it doesn’t require additional measurement equipment nor uses complex algorithms.

Keywords: 256-QAM, correction, imbalance, FPGA, modulator.


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Referencias


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