A Highly Linear Low-Noise Transimpedance Amplifier for Indoor Fiber-Wireless Remote Antenna Units

Abstract

This article presents an optimized design of a low-noise transimpedance amplifier (TIA) with high linearity for use in the downlink receiver of a remote antenna unit (RAU). The aim of this design is to be used in a cost-effective indoor distributed antenna system (DAS) for WLAN transmission using a mixed fiber-wireless system. The circuit topology consists of a fully differential shunt–shunt feedback TIA with digitally programmable transimpedance. An open-loop gain compensation technique is used to maintain stability and constant bandwidth (BW). The TIA has been fabricated in 65 nm CMOS technology with a 1.2 V voltage supply. The total power consumption of the TIA is 6 mW. A complete electrical and optical characterization with a 1550 nm PIN photodiode has been performed to demonstrate the reliable 54 Mb/s 802.11a WLAN transmission achieved with an error vector magnitude (EVM) lower than 3% for a 20 dB optical input range.

Radio over Fiber: An Alternative Broadband Network Technology for IoT

“…In this table are presented the results obtained in previous experimental works, highlighting specific design parameters for both RFoF and IFoF; this provides a clearer picture of how the two RoF strategies operate in terms of data transmission rate, source light (wavelenght), frequencies operation, applications, and type of fiber. The IFoF scheme presents a potentially good option for design, fabrication, and characterization for RAU devices, offering a cost-effective choice for DAS deployment [29,30].…”

“…With all this, IFoF presents major advantages over RFoF. First, since the optical signal is modulated with a much lower frequency, the use of an IFoF system minimizes the effect of MMF chromatic dispersion and simplifies significantly the integrated circuit (IC) design [28,29]. Moreover, it also drops the overall cost of the system, since lower performance and less expensive photonic devices can be used at both the BS and RAUs, for both O/E conversions in the downlink and E/O conversion in the uplink.…”

Testing RFoF link for transmitting HF-OTHR signal between transmitter and receiver shelters

“…Instead of transmitting the signal from Rx to Tx shelters via the coaxial cable, the Radio-Frequency-over-Fiber link would be used. Various RFoF architectures can be found nowadays in practical use [7], including the ones implemented with commercial ICs [8] and those implemented in dedicated CMOS technology [9], [10] -for both fronthaul and downlink connection applications.…”

Mejora de la linealidad de un VCSEL mediante técnicas de predistorsión para aplicaciones de radio sobre fibra

“…Los sistemas basados en transmisión de frecuencia intermedia sobre fibra (IFoF) presentan ventajas sobre los basados en transmisión de la señal de RF sobre fibra (RFoF) y los de banda base (BBoF) ya que no requieren la implementación de módems, como sí ocurre en la BBoF, la señal tiene el mismo formato que la señal RF generada en la BS, simplificándose la complejidad en el diseño de la RAU y disminuyendo el consumo y el coste [2]. Por otra parte, como la señal óptica está modulada a una frecuencia mucho más baja, en el rango de los 100 MHz, se puede emplear trasmisión por fibra multimodo (MMF), se minimiza el efecto de la dispersión cromática en la fibra y se relajan los requerimientos de los dispositivos fotónicos empleados en la conversión O/E para el enlace descendente y E/O para el enlace ascendente, ya que los dispositivos y circuitos optoelectrónicos caen dentro de la compatibilidad CMOS, alcanzando sensibilidades mayores que transfiriendo la portadora directamente sobre fibra (RFoF) [3]. La arquitectura para el uplink (Fig.…”