Small Cell Enhancements in Release 12/13

This chapter covers the small cell enhancements introduced in Release 12 in third generation partnership project (3GPP) as well as the items on‐going for Release 13. It first introduces the architecture impacts from the dual connectivity architecture options specified for Release 12. The chapter then covers the dual connectivity principle, followed with the more detailed impacts for the radio protocols as well as physical layer enhancements including 256 quadrature amplitude modulation (256QAM) and small cell on/off procedures. In dual connectivity, scheduling of user equipment (UE) transmissions is more challenging than in carrier aggregation, because scheduling decisions in the secondary eNodeB (SeNodeB) and in the master eNode (MeNodeB) cannot be instantaneously coordinated. The main motivation for introduction of 256QAM is the increase in peak data rates, achievable mainly in small cells. The chapter concludes by discussing the Release 13 enhancements, including uplink bearer split.