This document discusses wireless telecommunications facilities and trends in wireless technology. It provides an overview of how cell phones work and issues around siting facilities, including visual impacts and health concerns regarding radio frequency (RF) emissions. It notes trends toward increasing capacity needs, upgrades to 4G/LTE technology, and deploying more antennas closer to users through small cell sites and distributed antenna systems. The document also summarizes relevant federal rules and regulations governing the review and permitting of wireless facilities, including timelines for local approval under the FCC's shot clock rules and requirements for approving certain modifications under Section 6409 of the 2012 TRA.