Development of the LTE-Advanced standard continued for the next five years until March 2016 with the finalisation of Release 13, known as LTE-Advanced Pro. The major advances achieved with the completion of Release 13 include: MTC enhancements, public safety features – such as D2D and ProSe - small cell dual-connectivity and architecture, carrier aggregation enhancements, interworking with Wi-Fi, licensed assisted access (at 5 GHz), 3D/FD-MIMO, indoor positioning, single cell-point to multi-point and work on latency reduction. LTE-A Pro networks are often called "4.9G" or "Pre-5G" networks.
The key distinguishing enhancements were:
- 256QAM modulation in downlink (Release 12) and uplink (Release 13)
- LTE-U technologies, such as LTE Licence Assisted Access (LAA) leveraging the 5 GHz band
- Massive MIMO, such as 64T64R and 128T128R antenna technologies
- Beginning of IoT features such as LTE Cat-1
- Ultra low frequency bands: B31 (450 MHz) (Rel. 12)