GANDALF aims at demonstrating the simultaneous provision of Gb/s data rates to wireline and wireless access nodes (AN), employing a novel optical feeder concept. The proposed optical feeder employs a dual-drive Mach-Zehnder modulator at the central station (CS) operated in such a way that is possible to recover simultaneously the transmitted broadband data directly at base-band or intermediate frequency (BB/IF) and modulated onto a RF carrier. This architecture allows therefore to remotely feed heterogeneous (wireline and wireless) AN with very interesting features when compared to previous approaches based in fibre-radio techniques. The optical feeder architecture proposed by GANDALF allow a significant cost reduction with regard to other approaches as alleviate the bandwidth requirements at the transmitter end and simplify the electronics at both transmitting and receiving ends. At the ANs low-cost optoelectronic technologies (simplified hardware and reduced power consumption configurations) will be investigated, for example based in the use of electroabsorption-modulator transceivers (EAT) or Asymmetric Fabry-Perot Modulators (AFPM).
The proposed CS-AN
link configuration is compliant with core network technologies such
as DWDM and optical packet-switching. The offered bandwidth allows the
provision of multiservice and multiband applications satisfying future
requirements of access networks to cope with the expected evolution
of user and application requirements. Other feasible application is
the implementation of disaster recovery infrastructure.
One of the main targets of GANDALF is to identify on-going standards that employ modulation formats that are suitable to be employed both at BB/IF and RF frequency bands, such as DOCSIS or DVB-S, or to provide prospects to allow this heterogeneous functionality. Once pairs of such standards/technologies are identified, their simultaneous provision at BB/IF and RF and interoperability will be demonstrated both in a lab platform and under a small field-trial.