In-Building Wireless Requires Multiple Services, BTS Hoteling

November 13, 2013

Enterprise in-building coverage is widely seen as one of the next phases in wireless infrastructure deployment. When you look at the data growth rate and the ability of the carriers to meet those needs, there is a big disconnect, Peter Walters, Dali Wireless COO, told DAS Bulletin. He added that in-building wireless should be seen through the eyes of an IT professional.

“While carriers just want to lay out more wireless coverage and capacity to reach all of their customers, building owners are interested in wireless services that help to maximize the value of their building, which includes not only cellular but also Wi-Fi, public safety, indoor GPS, security camera data — a complete solution,” Walters said.

When There Is No Room at the Inn, the Base Station Hotel Is Always Open

One of the problems with implementing a head end for multiple operators and multiple technologies in an enterprise is that it can take up thousands of square feet of scarce, valuable real estate.

“With the ability to have an off-premise facility where the real estate is less expensive, we route those services and capacity into the enterprise location or virtualize the radio access network,” Walters said. “The opex is orders of magnitude more import than the capex; backup power, leasing of space, and the overall size of the system needs to be smaller.”

Traditionally, the head end equipment is collocated with a base station or a small cell. The signal is introduced into the head end, then the signal moves via fiber to remote amplifiers, which convert the signal to RF and connect to the antennas.
The Dali Wireless distribution system transports the RF signal from a base station to a remote location. This is enabled by transferring the RF signals into a digital data stream in the host and transporting them via optical fiber to a designated remote location, where they are converted back to RF, amplified and delivered to the end user.

“Distance comes into play. How far can you go with the signal from the head end to the remote? Can you use existing fiber infrastructure to reduce costs with the operators to do that?” Walters said. “There lies the opportunity to allow the operators to put their equipment anywhere they want to drive that capacity anywhere they want.”

Walters moderated a panel on base station hoteling at PCIA’s Wireless Infrastructure Show, Oct. 9, in Hollywood, Fla., where Mark Horinko, Airwavz COO, discussed the economics and business side.

“What we need to do as the wireless community is figure out how to provide the lowest cost per gigabyte,” Horinko said. “There are efficiencies in economics to be gained from pooling your resources in a centralized base station hotel.”
Base station hoteling is coming of age today because of advancements in the signal transport segment, such as the separation of the baseband from the amplifiers, the evolution of the CPRI protocol, the increase in fiber assets in urban areas, the commoditization of remote radio heads and advancements in DAS technologies, according to Horinko.

Thomas McCarthy, director network operations, Transit Wireless, touched on the challenges his company has faced in providing DAS in the New York subway system, such as the large power requirement and limited potential locations for the base station hotels.
“Limited RF-over-fiber budgets govern where we can place our base stations and how many base stations are needed,” McCarthy said. “In the New York area where DAS is ideal, there are not a lot of buildings with roof space available.”