Fiber-optic solutions for FTTA radio systems
Thanks to the development of telecommunication systems modern mobile networks use optic fibers for a connection between a base station and an antenna. Optic fibers replaced copper cables which contributed up to 50 % of the loss of signal and increased the cost and difficulty of installation. FTTA technology (Fiber To The Antenna) is a technology of connecting cables with antenna. The fiber-optic solution in contrast to a traditional mobile network reduces the cost of installation through a decreased use of devices which enhance the signal, using up a small area for installation.
Mobile networks operate in ranges between 900 MHz – GSM to 3,5 GHz – WiMax. As the technology develops frequencies, the speed of transmission, the area of range and the number of employed field antennas in the range of the network increase. The number of radio antennas for WiMax is four times larger than for UMTS network which also increases the number of required base stations.
In FTTA all equipment, that is: frequency and power supply electronics are located in an antenna head near antenna instead in a base station. The head is connected to the base station with an optic fiber. The fiber-optic connection in FTTA system may be single mode or multi mode, operating at two uplink and downlink frequencies. Small distances of optical transmissions that are used currently lower the cost of the system since there is no need to install enhancing devices.
The greatest challenge for FTTA technology is their efficiency in difficult enviromental conditions, and an answer to that is a possibility of installing an antenna head which operates in extreme temperatures from -40°C to +60°C with a possibility of warming them to 85°C without turned on cooling system. Thanks to those requirements dedicated ODC fiber-optic connections for FTTA network were created, resistant to water and corrosion, with impermeability class of IP 68.
The basis of FTTA system is a radio base station placed in a surface location, remote antenna head and radio antenna. All elements of the system are connected together with dedicated fiber-optic wire harnesses, copper wire harnesses and power cables.
FTTA may be used where there is a difficulty with gaining an access to an existing fiber-optic network or in dense development of multi-storey houses,. All new 3G systems, including TD-SCDMA and WiMax are based on the use of FTTA systems.