5G-NR Bandwidth Efficient Modulation Options for Efficient Link Operation that are Compatible with mmW Transistor Nonlinearities

The 5G network has a goal to significantly increase its energy efficiency with respect to the energy draw of the LTE network. The decision to use OFDM-based modulation for 5G-NR forces a low-valued ceiling on achievable energy efficiency from any linear power amplifier. This ceiling is lowest for amplifiers operating at frequencies near and above 30 GHz: the millimeter-wave bands. Transistors behave differently at these high frequencies, and the modulation used must change to match to these different characteristics. Ring oriented constellations with polar filtering meet these changed conditions.