User Manual

DELTANODE FIBER DAS MANUAL
©DeltaNode Solutions 2012
7
Revision 12-03
 Single mode fiber
 Angled connectors
 Optical loss < 15 dB
1.2 RF on fiber
A fiber distributed antenna system (Fiber-DAS) is a very efficient way of transmitting radio signals over
large distances. Up to about 25 km of fiber between the head-end and the remote unit is allowed,
providing that the radio access technology (RAN) do not suffer timing issues and that the fiber loss is
within the specification.
The main principle is to use an infra-red light source which is modulated with the combined radio signals
that needs to be propagated. The fiber channel system is ultra wide-band, ranging from 88 MHz up to
2600 MHz and thus covering most types of radio communication systems such as FM broadcast, VHF
communication radios, TETRA, GSM, CDMA, WCDMA and other radio access technologies that are
available.
The dynamic of the fiber is good enough to tolerate multi-carrier, multi-band and multi-operator
solutions this way, but of course they all share the available dynamics and if there are a very large
number of carriers the fiber attenuation needs to be looked at of course.
Because most land mobile radio systems and cellular systems are using Frequency Division Duplex (FDD)
this means that there needs to be either two separate fibers, one for the uplink (signals from the
terminal towards the base station) and for the downlink (signals from the radio base station towards the
terminal) or they may be multiplexed on the same fiber using different wavelengths.
The most popular way is to use wave-length division multiplexing (WDM)
which is the normal configuration of the DeltaNode Fiber-DAS concept.
However, separate UL/DL fibers can be used if it is necessary or desired.
Because the modulation is analogue the system requires the fibers to be
of single mode type. All connectors used in DeltaNode equipment for Fiber-DAS are of SC-APC type with
a 7° angle. It is very important that all connectors in patches et cetera between the Master Unit (MU)
and the Remote Unit (RU) are angled, otherwise reflections are caused which will cause problems with
the quality of the signals through the system.