The growth of smartphones has multiplied mobile data consumption, and capacity has become an issue of key importance. Because of congestion in the network, with both dropped data and voice sessions, users' experiences are degraded. Purchasing additional spectrum, which is a finite resource, is impractical for cost and timing reasons. One of the most efficient ways to improve capacity within a network is to reduce the cell size radius, and place the cell sites closer to each other, resulting in a more densely packed network of smaller cells. Outdoor small cells include femtocells, picocells, and microcells. There are economic advantages, as well as network advantages to deploying small cells. This study explores these advantages as well as the problems that are associated with these deployments. It also addresses other outdoor small cell topics such as the state of the market and its direction over the next five years, as well as drivers and barriers. Forecasts for small cells are segmented by region, power output, location, and radio interface for both shipped units and revenue.