The novel software radio concept is a promising technique to develop new RF front-end architectures. It has been used to implement a transceiver for cellular mobile radio Base Station equipment. The most important technical issues are discussed and the prototype developed in Siemens R&D labs is presented. Results of the measurement campaign are shown.

The Software Radio Technique Applied to the RF Front-end for Cellular Mobile Systems

In order to asses free space optical links, using a Cassegrain telescope, for both classical (i.e. coherent and direct
detection) and quantum (coherent, Dolinar-Kennedy system) several scenarios were analyzed. This analysis was
conducted through a software tool that uses some specific parameters imposed by the environmental condition and
hardware used, such as: pointing and tracking errors, turbulence, modulations schemes, and visibility, among others; in
order to obtain the general performance parameters of the simulated link, such as: bit error rate and the photons number.
The software developed allows the user to produce useful way to assess the possible success of the implementation of
the free space optical link, or a way to identify phenomena that might suggest hardware adjustments to improve the
overall performance of the system. Results allow the revision of the expected link performance for a quantum key
distribution system; although it is possible to use it for general optical quantum communications systems.

Scenario analysis for performance evaluation of free-space quantum and classical communication channels

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.

C. Savazzi

Papers

High speed optical data link for Smart Antenna Mobile Radio System