Envelope Tracking System for High Power Applications in Uplink 4G/5G LTE Advanced

The research area of improving the cost, performance and the size of RF transmit solution for 4G/5G is very active with many developments. 5G will bring high data capacity and low latency using sub-6GHz and mmWave spectrum, with the first deployment using sub-6GHz bands. The increased adoption of powerful worldwide mobile devices has been in made possible due to increased computational power of CMOS technology in lower feature nodes as FinFet 7nm/14nm. This has also made it possible to essentially enhance RF CMOS through digital signal processing (DSP) and digital calibration which are part of the modem and application processor. Despite this progress, there is a shift in terms of what parts of the RF system are portioned in advanced CMOS nodes and what blocks are left and integrated together with other analogue and RF blocks in a front-end module (FEM). This paper proposes a solution for this partitioning for lower cost and size with high linearity performance and a new envelope tracking system for high power 5G LTE sub 6 GHz. This paper presents also how these modules integrate into a full 4G/5G system RF front end (RFFE) for mobile applications.