LTE equipment is not only a heavier weight for the tower to bear than its 3G predecessors, but it presents more surface area for increased wind loading. Additionally, new demands for fiber to the antenna (FTTA) are increasing the complexity of tower deployments and network upgrades.
The good news is new mounts are entering the market to accommodate the heft and complexity of the LTE era equipment.
One example of the next generation of mounts is the V-Frame Boom Gate, from Connect-It Wireless, which was engineered to handle today’s heavier loads. At 181 MPH winds, the maximum combined load area for the new V-Frame is 7,945 square inches, according to Jim Schultz, founder and president of Connect-It Wireless.
“As the amount of material added to the tower increases, a mount is required that’s tough enough to handle the wind area loading,” he said. “And considering the max combined load weight is a solid 650 lbs., it’s a durable, heavy duty application that the new upgrades demand.”
The V-Frame adheres to building codes across the nation, such as the 2010 Florida Building Code, TIA-EIA-222-G-2, and A.S.C.E. 7-10.
Also in response to the rollout of 4G remote radio heads, Valmont/Site Pro 1 released the Ultra-Low Profile (ULP) Ridged T-Frame monopole mount.
The size and weight of the LTE equipment has led to a 25 percent increase in wind loading on the mounts, according Brandon Chapman, Valmont/Site Pro 1.
“A lot of T-arms were being sold for LTE systems, because they are economical compared with a platform mount,” Chapman said. “Through analysis of these mounts, I found that they were pushing their boundaries in terms of strength.”
T-arms are popular because of their price, but Chapman believed that what was needed for LTE antennas was the strength of a platform mount. He then set out to create a mount that would be economical like a T-arm and strong like a platform.
“I designed the ULP to have the cost of a T-arm with the strength of a platform. Twice the strength of a T-arm,” he said.
Valmont/Site Pro 1 analyzed the ULP for a 200-foot tower with a 90 MPH wind, using ANSI/TIA-222-G-2005. Four antenna loads were evenly spaced across each face of the mount, centered on the centerline of the mount. Based on the design criteria, the mount capacity is 5,400 pounds (170 square-feet).
The maximum normal force per antenna pipe is 450 pounds (14.1 square-feet) with a maximum tangential force of 450 pounds (14.1 square feet). The weight of each antenna was considered to be a maximum of 200 pounds. The mount will also support a nominal load of 250 pounds at two locations simultaneously (500 pounds total) to provide access for climbers.
Limiting the weight and wind loading of the mount itself were also factored into its design.
Remote Radio Deployments Present Fiber Optics Challenge
As carriers opt to deploy remote radio units, fiber-optic cables typically run up to the top of the tower to connect baseband equipment. This brings a new level of complexity for tower technicians. And the challenge strikes cell tower sites worldwide.
“It has become increasingly complex, time-consuming and expensive for operators to maintain existing cellular sites. Typically, the infrastructure had to be assembled on-site at the top of the tower, and the lack of a single tower top design standard has made each upgrade a challenging process,” Bill Walters, Commscope spokesman, told AGL Bulletin.
In Doha, Qatar, Commscope collaborated with an international communications provider, Ooredoo, to develop a factory-assembled tower-top base station remote radio, which was made according to a single global design standard.
“The aim of the tower top development is to create and maintain a network that is radio vendor agnostic and does not require significant on-site remote radio modifications for future upgrades,” Walters said.
The tower top solution will become Ooredoo’s standard cell site design across its markets in the Middle East, North Africa and Asia, in line with the company’s network modernization strategy of upgrading or replacing 15,000 of its base stations.
Building on its partnership with Ooredoo in standardizing tower tops for cellular sites, CommScope is bringing a solution for enabling fiber-to-the-antenna site deployments to America.
“FTTA installation needs to be standardized, because when you have electronics at the tower top plus fiber optics, it gets more complicated, difficult to install and there is more chance for error for the installer,” Walters said. “So we started using a pre-assembly of the whole unit that goes on the tower top, including the base station antenna, mounting, the remote radio unit and the cabling.”
The FTTA Turnkey Solution, part of the Andrew portfolio of wireless solutions, is designed to standardize and simplify remote radio unit (RRU) installation, as well as accommodate multiple RF technologies and frequencies. The solution includes the Argus UltraBand multiport antennas; HELIAX FiberFeed hybrid fiber and power trunk cables; HELIAX SureFlex RF cable assemblies, cabinets, structural supports, connectors and assemblies.
The optional Andrew SiteRise offers pre-assembly and pre-testing of all RF equipment prior to hoisting up the tower.