Multitenant small cell deployments prove challenging

Wireless carriers and their partners are attaching small cells and antennas to street light poles, utility poles and custom-built structures in cities all over the U.S. The new cell sites will support increasing traffic on LTE networks today and on 5G networks tomorrow.

Some companies building small cells for the carriers want to replicate the tower industry's model of shared infrastructure by placing small cells for more than one operator on a single pole. This enables the infrastructure provider to use the same fiber assets to serve more than one customer, and it minimizes disruption on the crowded city streets where the carriers need small cells.

How successful will the shared infrastructure model be for small cells? Companies are making it work, but there are challenges. Crown Castle said recently that more than half the small cell nodes booked during the first quarter were for co-location on existing fiber infrastructure, and the company is in the process of adding a second operator's small cells to street poles in Charlotte, North Carolina. But Crown Castle said its carrier customers are reluctant to share antennas. This can present a challenge because most poles cannot support two antennas at the top.

ExteNet Systems CTO Tormod Larsen said his company has added a second operator to poles in San Francisco, and that most of ExteNet's networks support multiple carriers even if the carriers may not be sharing a pole. He said it can be hard for two operators to share a pole when each one needs a large amount of equipment. Vendors have worked hard to create compact solutions, but when an operator wants to use one small cell location to support several frequency bands, the pole gets crowded.

"We are working on quite a few projects where it is 3G or 4G and they want to upgrade to 5G and include the existing equipment as well," said Larsen. "Some of those are pretty massive. The amount we’ve been asked to be put at a particular location is pretty stunning. You end up with basically everything except the kitchen sink: All frequency bands plus whatever frequency band they want for 5G plus LAA. The equipment hasn’t come to a point where they are consolidated so we are ending up with a lot of boxes that need to be put in a shroud and then consolidated onto fiber. So that is a threat to co-location."

Larsen said that in some cases carriers will end up with six to eight pieces of equipment at a single location, which can be an unpleasant surprise for city planners who thought they approved a small pole attachment. 

When carriers manage their own deployments instead of working with a third party provider like Crown Castle or ExteNet, they often plan to use all available space on a pole. In some cities, this may not be a problem because of the large number of available poles. For example, Sacramento in California has 40,000 sites available for small cells, according to XG Communities, which is helping the city organize and lease its assets.

XG Communities said in March that its database included roughly a quarter of a million assets in 27 cities available for small cell deployments. At that time, the company was not seeing applications for co-locations on any of those assets.