Front-end FTTA Site Preparation Limits Back-end Delays

Deploying remote radio units at cell sites means installing fiber and power cabling. Conducting a pre-construction site audit helps avoid delays and waste, as Larry Seper explains.

I was reminded of the importance of proper project planning last weekend. When installing a chandelier light fixture at home, I cut the power cord after a quick measurement, thinking I had the correct length. It turned out I made a mistake and left the cord an inch short. What should have been a 30 minute project became a two hour ordeal because I hastily bypassed the appropriate front-end measurements.

Deploying remote radio units (RRUs) at cellular sites can bring about similar situations. RRUs require operators to bring factory-terminated fiber and power cabling up to the tower top, individually or bundled together in a hybrid solution. Making length adjustments to fiber or hybrid fiber cables onsite requires extensive cable jacketing preparations, a more challenging task than working with coaxial cable. In fact, most carriers do not even allow field terminations of fiber because it opens the door to too many problems.

Excessive lengths of fiber cable can also be challenging because there is usually limited space available to coil the cable on a crowded tower top or in an equipment shelter. The ordering of hybrid cables that are too long or short can be costly and time consuming. The cumulative effect on a project extends past the cost of re-ordering products. Remobilizations and delays to construction/integration schedules can be just as, if not more, costly than the re-ordered cable.

This situation creates an increased need for front-end preparation and precision when deploying RRUs and fiber/power cabling. That is one of the reasons why CommScope created its complete Fiber-to-the-Antenna (FTTA) Turnkey Solution. Part of that solution involves conducting a pre-construction site audit before placing the order for equipment. The site audit process, conducted by Andrew Systems, Inc., starts with mapping the site to verify or determine where RRUs, breakout boxes, over voltage protection and other equipment will be installed. We can provide photos indicating the location for all key components of the system. Once the locations are determined, we provide the measurements for cable lengths, along with all required components, supplying quantities and the CommScope product information. Two separate bills of materials (BOM) are included, one detailing the RF equipment required for operators and a separate installer’s BOM for mounting equipment and the other common accessories required for a trouble free installation.

Wireless networks are getting more complex, and implementing RRUs and fiber to the antenna is part of that complexity. Doing the necessary planning before the site installation begins is a sensible and cost effective process to avoid delays and waste. Have you implemented RRUs yet at a site? What issues did you run into? What other factors need to be considered that might be overlooked?