LTE in unlicensed spectrum using licensed-assisted access

It is forecasted that mobile data traffic will increase 1000-fold from 2010 to 2020. As a result, the network must evolve to meet the large and rapidly growing data demand. An effective approach for increasing network capacity is to use additional spectrum. In Rel-13, LTE deployment in unlicensed spectrum is being considered. This feature is called Licensed-Assisted Access (LAA) using LTE. Unlicensed band is attractive due to the large amount of available spectrum. In this paper, we provide an overview of LAA including standardization progress and potential changes. A fairness mechanism for LAA coexistence is also presented. Downlink system performance is analyzed for multi-operator LAA deployment. Three representative scenarios are considered - indoor hotspot, indoor office, and outdoor small cell. It is shown that LAA can offer significant additional capacity to the network. Analysis shows that a co-existence mechanism such as listen-before-talk is needed in co-channel multi-operator deployment to ensure that all users can receive service. With listen-before-talk, co-existence is not an issue even in dense deployment.