Long-term evolution (LTE) and LTE-Advanced activities in small cell networks

The general definition of a small cell is the low-powered radio access node operating in licensed and unlicensed spectrum with the smaller coverage of ten meters to one or two kilometers, compared to a mobile macro cell with a range of a few tens of kilometers. With the introduction of this new concept, the heterogeneous network (HetNet) constructed with different layers of small cells and large cells can deliver the increased bandwidths, reduced latencies, and higher uplink (UL) and downlink (DL) throughput to end users. Since 2009, the standard evolution of the small cell related topics has been studied in 3GPP (The 3rd Generation Partnership Project) LTE (long-term evolution) and LTE-Advanced. The following sections in this chapter will introduce the standardization progress of LTE and LTE-Advanced in small cells.