Analysts predict that more than 4 million more will be deployed globally this year alone, and the small cell market, which had been growing slowly for lack of a need to make them, is now expanding at 50% per year to accommodate LTE-Advanced, representing more than $4 billion in revenue. These figures will likely soon be incremented upward once deployments at 3.5 and 5 GHz increase. These estimates also do not include millimeter-wave deployments, which except for FWA won’t appear for years (see table 1).
This being said, the same characteristics the make the millimeter-wavelengths a poor choice for long-range communication make them almost ideal for the very short distances required for small cell-to-small cell and smartphone-to-smartphone links, as well as high-speed backhaul. They might also find homes in some industrial IoT environments, where they will compete with entrenched protocols like ZigBee, Bluetooth, Wi-Fi, Thread, and Z-Wave. Small cells operating at millimeter-wave frequencies could also collaborate with these protocols, providing a more seamless way to integrate short-range mesh networks into the long-range solutions (cellular and LPWAN) that provide connections to the world outside the plant.