Hybrid Cables simplify FTTA deployment

By: Bryan Blunt, Product Management Director, Wireless Products

Wireless technology continues to evolve, with increased deployment of LTE/4G and the industry rapidly moving towards 5G.  Further, new antenna designs such as multiple-in multiple-out (MIMO) make high capacity wireless communication using coaxial cable increasingly difficult.  Thus, the need to handle ever increasing amounts of data across the cable backhaul infrastructure and the need to provide reliable power to wireless equipment place even harsher demands on the tower’s cable infrastructure. 

Operators have found that they can gain capacity, lower energy consumption, and improve the quality of signals by moving equipment even closer to the antenna.  This has led to a growing reliance on fiber-to-the-antenna (FTTA).  Of course, by placing fiber equipment near the antennas on the tower, there is the added benefit of reduced real estate costs for the entire site.

It is estimated within the industry that, in coaxial-based systems, as much as 50 percent of the RF signal may be lost between the antenna and the remote radio unit (RRU) on the ground.  Clearly a costly inefficiency.  FTTA, on the other hand, places the RRU adjacent to the antenna, utilizing very short coaxial connectors between the two.  The RRU communicates with controllers on the ground over a fiber connection.  An added benefit of the fiber-based system is the elimination of the need for a RF power amplifier along with their powering and cooling costs.

For this new FTTA architecture to work properly, the fiber equipment will need to have both power and connectivity.  Early on, this need was addressed by running fiber in a point-to-point fashion from the base band unit (BBU) at ground level up to the RRU at the top of the antenna.  Separately, power cables were extended up the tower to the RRU.  Although efficient at the start, this approach became more expensive as additional RRUs were added. 

Today, manufacturers such as Amphenol Broadband Solutions provide hybrid cables which bundle power and fiber cables together in one sheath.  Such a cabling option eliminates the need to run multiple cables each time equipment reinforcement is necessary at the top of the mast.  Additionally, such a cable can reduce the amount of needed cable, and therefore the resulting cable installation time, by as much as 50%.

When contemplating a hybrid cable solution for an FTTA architecture, there are multiple important considerations:

  • Does the vendor manufacture the power cable in-house and bundle the power/fiber under one roof?  Manufacturers that do this can usually offer the best lead times and overall value.
  • Is the cable of a lightweight non-corrugated design, allowing a more cost-effective solution?
  • If a more hardened installation is desired, is the fiber available in an armored version?
  • Does the manufacturer offer a variety of gauge sizes, fiber counts and new configurations?
  • If a longer cable run is necessary, is a low inductance design available?
  • Is the fiber offered in either single- or multi-mode?
  • Does the cable meet all UL Listing requirements?
  • Is the cable made in North America, thereby providing low lead times and quick turnaround options?
  • And finally, does the manufacturer offer not only cable, but antennas, cable assemblies, fiber management panels, and a full suite of connector and peripheral products and services to support the network provider’s deployment plans?

Indeed, hybrid cables offer a solid solution to growing wireless capacity as efficiently as possible.  By choosing a highly experienced manufacturer, a system operator can grow its network to meet the continuing demand for ever-greater wireless capacity.