The small cell market continues to expand, and Crown Castle’s Mike Kavanagh pointed to two big factors as evidence: Small cell buildouts are starting to happen in smaller, tier 2 markets, and some small cell locations are now serving more than one carrier.

Small cells are “a big part of every big carrier’s build,” he said. “It’s a good time to be in the space.”

In the early days of small cells half a dozen years ago, Kavanagh said that a major installation would cover 50 nodes in a city. Today that number is reaching 2,000—and in some dense markets it can grow to 7,000. “You’re utilizing small cells as a much bigger element of the network build,” he said. “You’ve got to have that tower layer. And you’ve got to have small cells.”

He said in some deployments Crown Castle is seeing 2 to 4 small cells per mile, and in some dense, urban areas that number grows to 7 to 12 per mile. Kavanagh, the company’s SVP of sales and its chief commercial officer, said that Verizon kicked off the push toward small cells, but today all of the nation’s largest wireless operators are embarking on major small cell deployments.

And a big driver of revenues for Crown Castle is the growing trend toward multitenant small cells, which Crown Castle calls “leasing up.” Essentially, Crown Castle typically builds a small cell for one carrier’s equipment, but increasingly the company is adding equipment for a second carrier to that location, thus deriving more revenues per small cell site. Such site sharing is typical in the macro tower business.