Enhancements of 3GPP LTE-Advanced: An Overview of LTE Releases 11 and 12
In this paper, we perform a survey on new 3GPP LTE-Advanced enhancements, covering the technologies recently adopted by 3GPP in the Release 11 and those being discussed in the Release 12. In more details, we introduce the latest enhancements on carrier aggregation (CA), multiple-input multiple-output (MIMO) and coordinated multi-point (CoMP) as well as three-dimensional (3D) beam-forming. Moreover, considering that network nodes will become very diverse in the future, and thus with heterogeneous network (HetNet) being a key feature of LTE-Advanced networks, we also discuss technologies of interest in HetNet scenarios, e.g., enhanced physical data control channel (ePDCCH), further enhanced inter-cell interference coordination (FeICIC) and small cells, together with energy efficiency concerns. In particular, we pay special attention to dynamic time division duplex (TDD) technologies, and present performance results that shed new light on this topic.