3 Small Cells for Every Macrocell?

By 2017, Ericsson expects each macro base station in urban areas will be supplemented by about three small cells. 

Today, there are about five million macro base stations deployed worldwide and those in metro areas account for about 15 percent of the total, or about 750,000. That suggests a total of perhaps 2.25 million small cells. 

It always is difficult to predict the deployment of small cells because that category sometimes includes virtually all cell sites smaller than a macrocell, including potentially large numbers of consumer grade units used inside homes or offices, plus larger small cells deployed as part of the public mobile network.