High speed optical data link for Smart Antenna Mobile Radio System

Abstract

In order to simplify site installation and reduce related costs, a high-speed Optical Data Link (ODL) connecting active antennas and Base Station in new generation Mobile Radio System has been developed. Using the Smart Antennas System in a three-sector site, the number of feeders becomes unmanageable and costly. Thanks to the Multicarrier Software Radio approach, it is possible to place antenna and wide band RF hardware close together, transporting IF signal in digital format through high-speed serial data bus. The ODL was built up with Low Cost Gigabit Rate transmitter/receiver chipset and Gigabit Ethernet 1300nm Laser Transceiver. A 50-meter fibre cable has been used to cope with the standard antenna tower height (a three kilometre fibre length is also possible for distributed antennas in a microcell deployment). Reference signals like A/D and D/A signal clock, local oscillator (LO) and frequency references are delivered to remote parts by optical link as well. The critical aspect related to A/D clock integrity has been successfully solved.