Constant envelope transceivers in millimetre-wave massive MIMO: EVM and link budget considerations

RF 30 GHz ray-tracing simulation results are presented from a conceptual Massive-Multiple Input Multiple Output (M-MIMO) propagation model in an urban canyon. The usage of Constant Envelope (CE) RF signals is evaluated in both propagation ray-rich and ray-sparse scenarios. Multiple mobile terminals are simulated each employing single carrier Phase Shift Keying (PSK). It is found that once an operational link budget is achieved CE transmitters have negligible effect on a received Error Vector Magnitude (EVM). Finally it is found that the EVM is a function of both richness of propagation rays as well as the relative proximities of mobile users. A worst-case EVM of circa 25% is observed when terminals are separated by 1m reducing to circa 5% when terminals are separated by more than 4m.