11 / 3 / 2011
The volume of data traffic in mobile communication networks has literally exploded. Data volumes have quadrupled in the last two years and are expected to triple worldwide over the next two years. Why the sudden increase? The accessibility of smartphones such as the BlackBerrys and iPhones to wide sections of the population has seen data overtake calls as the main component of mobile phone communication.
Advances in mobile phone technology mean you can now read your e-mails and morning newspaper as soon as you wake up and watch the previous evening’s sports highlights during breakfast – long before you’ve even switched on your computer. Mobile data rates have mutated into a cash cow for mobile phone providers and mobile broadband is now able to compete directly with landline broadband. However, this is only possible if the mobile networks are capable of handling the enormous volumes of data. The 3G networks that currently exist are already operating at up to 80% of their capacity in many places. Existing networks will not be able to cope with the forecast growth and demand for capacity will outstrip supply. Network failure is already a fairly common occurrence and often means high costs for operators due to compensation for customers. This situation has pressurised mobile communications operators worldwide to invest in 4th generation networks such as LTE. LTE stands for Long Term Evolution and promises data rates of up to 100 Mbps, which is ten times what current networks are able to deliver.
Increased performance, reduced operating costs
This expansion, however, cannot be achieved without upgrading the network infrastructure. New, more effective solutions are needed to process and transmit the huge data volumes. This is costing mobile communications operators vast amounts of money. However, by investing in new technologies, operators can effectively kill two birds with one stone. While the transmission capacity of the network has increased many times over, the operating costs for maintenance, energy and data connections have been reduced significantly.
Current solution is inefficient
Conventional installations use corrugated coaxial cables to transmit the radio frequency signal from the base station to the remote mast antenna. Depending on the cable length and cable cross sections, up to 50% of the transmission signal power is lost due to attenuation in the cables. In order to supply the antennas with the required RF power, the feeder lines from the base station must be supplied with up to twice the power. This means a lot of power for little benefit and therefore high costs for network operators.
The future is Fiber-To-The-Antenna
Understandably, there has been a great deal of interest in finding an alternative. The answer is Fiber-To-The-Antenna, or FTTA for short. This solution involves the use of fiber optic cables, which have no signal losses, from the base station. At the top of the mast, they are routed to a remote radio head in close proximity to the antenna. Expressed in simplified terms, the remote radio head acts as a converter, converting the fiber optic signal into a radio frequency signal, which can then be transmitted by theantenna. The radio frequency signal is generated close to the antenna and transmitted with minimal losses over just a few metres using a high-performance RF cable and then emitted. With this Fiber-To-The-Antenna solution, all the power sent from the base station reaches the antenna with no loss. In addition to supplying data using fiber optic cables, the remote radio head itself must be supplied with power using a low frequency copper cable. Power consumption is low, however. Overall, the operator’s energy costs are significantly reduced.
Cost-effective upgrade thanks to FiPro
Network operators are showing significant interest in new Fiber-To-The-Antenna solutions. However, because so much was invested in the previous infrastructure, there is a reluctance among network operators to stop using it. Vodafone Germany has therefore developed the FiPro (Fiber and Power to the roof) method for upgrading from conventional systems with conventional corrugated coaxial cables to Fiber-To-The-Antenna systems. With this method, the existing coaxial cables are converted and do not all have to be relaid. The slim-line fiber optic cables are routed through the large hollow inner conductor of a corrugated cable up to the remote radio head. Plenty of space is available for this purpose.
The fiber optic cable is thus also protected against external influences. A second corrugated cable is converted to supply power to the remote radio head. Existing cabling, which is often integrated into facades, can thus be used without having to undertake any demolition or masonry work. With this method, a conventional corrugated system can be converted to a Fiber-To-The-Antenna system quickly and inexpensively. Completely new installations are, of course, also an option along with this method.
Fiber optics enable centralised control
Fiber optic cables offer another major advantage. In conventional systems with corrugated coaxial cables, a maximum distance of 100 metres is possible between the base station and the antenna due to the large signal losses. This means that expensive telecommunications rooms have to be rented near each antenna. Given that fiber optic cables transmit the digital data between the remote radio head and base station with almost no loss, distances of up to 20 kilometres are possible. This means that base stations for multiple antennas can be housed cost-effectively in a central telecommunications room and network planning is rendered more flexible.
Established full-range supplier
HUBER+SUHNER was already an established full-range supplier of antenna supply lines for conventional installations. From SUCOFEED corrugated cables in all sizes with matching QUICK-FIT connectors as antenna supply lines, through RF assemblies for connecting the antenna to the network on top of the mast, to lightning protection solutions of all types and additional products for efficient installation – with HUBER+SUHNER all components are supplied from a single source. As is the case with conventional systems, HUBER+SUHNER supplies complete connectivity solutions from the antenna to the base station for new systems. Whether a conventional solution based solely on radio frequency components is required, or a new-generation solution that also combines fiber optics and low frequency, HUBER+SUHNER is completely at home in all three technologies.
Strong cables, strong connectors
To ensure simple and efficient installation for remote radio head systems with fiber optic and copper connections, HUBER+SUHNER can supply assembled, ready-toinstall MASTERLINE fiber optic cabling systems on request. The remote radio heads are connected to the outgoing lines of these systems. Because remote radio heads are exposed to rain, corrosion and extreme temperature fluctuations, the robust ODC and new Q-XCO outdoor connectors or an LC indoor connector, which is protected by a special pre-chamber, are used. HUBER+SUHNER also supplies the low frequency cables required for remote radio head power supply as well as overvoltage protection modules, which protect the remote radio heads and power supply units connected to these copper cables. The portfolio also includes the connectors required in a FiPro installation for converting the RF corrugated cables to a power supply line.
LISCA cable assembly and lightning protection
In addition to the required fiber optic and low frequency components, HUBER+SUHNER supplies the typical radio frequency products that are essential in a remote radio head installation. The RF cable assembly LISCA provides the connection from the remote radio head to the antenna at the top of the mast. LISCA stands for Low Loss and Low Intermodulation Soldered Corrugated Cable Assembly. The low attenuation ensures that the entire signal is received and an extremely low PIM (Passive Intermodulation) value is achieved thanks to the design. In other words, interference from the transmission band to the reception band is very low. This allows the use of virtually the entire frequency bandwidth. HUBER+SUHNER supplies the connectors on the LISCA assembly in a number of variants, all of which are waterproof to IP 68. HUBER+SUHNER also offers RF lightning protection components, which are also LTE-capable for broadband use. These continue to be used in remote radio head installations, particularly in cases where the LISCA assembly is longer than 1.5 metres.
Three technologies from a single source
A wide range of installation options is available for remote radio heads, including single cables, multi-riser cables and hybrid solutions through to the FiPro method. HUBER+SUHNER, a leading specialist in remote radio head installations, can supply all solutions from a single source thanks to the combination of radio frequency, fiber optics and low frequency under one roof. Reliable 4th generation mobile networks will soon be able to process the rapidly increasing data traffic. Having a telephone conversation with your niece on the other side of the world is one thing. Using the mobile webcam on your smartphone to wave to one another at the same time is another. Welcome to the future.
Remote radio head for antenna and building installations
Remote radio systems can be used for all types of cell sites as well as for conventional mast installations and building installations.