Análisis del impacto de la conversión Analógica a Digital en el desempeño de Sistemas RoF Digitalizado

Abstract

Introduction: The impact of the digitalization process on the performance of a scenario based on Radio-on-Fiber technology at intermediate frequency is numerically assessed.

Objective: Assess the impact of the process of digitalization, in the performance of scenario Radio-over-fiber digitized intermediate frequency (IF-DRoF).

Methodology: The performance of an IF-DRoF system against the error is evaluated as a function of the link distance and the number of resolution bits of the Analog-to-Digital Converter (ADC), and the results are compared with the analog Radio-over-Fiber (ARoF) architecture. The DRoF scenario introduces an ADC at the transmitter to digitize the signals, and a Digital-to-Analog converter (DAC) at the receiver to reconstruct them. The optical transmitter uses a low cost Directly Modulated Vertical Cavity Emitting Laser (DM-VCSEL).

Results: IF-DRoF scenario extends the transmission distance by 18 km (from 25 up to 48 km), and 22 km (from 25 up to 47 km) using an ADC with 4 and 8 bit of resolution, respectively, when compared to ARoF. Also, for a bit error rate (BER) equal to 10^-9, the IF-DRoF system increases the range by 7 km, and the bit rate scales as the product number of resolution bits of the ADC × sampling rate (8× 1.25 Gb/s = 10 Gb/s). The sensitivity level measured at the receiver for a maximum range of 42 km was -21 dBm for a BER of 10^-5@ 4 bits of resolution.

Conclusions− IF-DRoF system is a flexible and low-cost solution that extends the transmission distance and scales with bitrate as n bits × sampling rate comparing with analog RoF. It is shown that the dynamic range is independent of the transmission distance except when the signal level falls below the sensitivity of the optical link photodetector.