Developments announced at MWC 2014 suggest that the adoption of envelope tracking, CMOS PAs and front-end CMOS integration in cellphones are now accelerating rapidly, all in support of LTE:

• Qualcomm is shipping the first ET for cellphones in two mobile devices now. This puts Qualcomm ahead of the competition and should help them maintain high share in LTE, including TD-LTE, expected to ramp this year in China.  TD-LTE may benefit from ET even more than FD-LTE.  None of the other ET vendors have announced chipset partnerships yet.  With Qualcomm maintaining LTE chipset market share over 95 percent, right now any such ET-chipset partnerships would have limited financial impact.
• Nujira claims that Qualcomm’s ET uses a simple form of DPD, which comes with a power consumption penalty, and that Nujira’s ET does not require DPD, making it superior to Qualcomm’s in terms of power consumption. 
• Quantance says that their ET chip has a much smaller footprint than Nujira’s. 
• Both Nujira and Quantance say that R2 Semi’s ET, supposedly selected by Broadcom, is a lower-cost, relatively low performance (and low bandwidth) solution.
• ET from Eta Devices, rumor has it, supports 80 MHz channel bandwidths and probably 160 MHz.  The other solutions only support 20 MHz channels or less in first implementations.  Unlike the others, the Eta Device solution can support 802.11ac Wi-Fi.  Adoption of 802.11ac is still very low, but within a few years most mobile devices will probably use at least the simplest (1 x 1 ) form.
• RFaxis demonstrated a new CMOS PA with monolithically integrated ET.  The RFaxis solution, the company claims, works with any cellular chipset using standard or proprietary interfaces.

In related news, Peregrine Semi’s demonstrated their new CMOS PA, showing that the PA could match the power added efficiency of the Skyworks linear PA used in the latest iPhone 5 models point-for-point at all power levels.   The proposed merger of RFMD and TriQuint means that all of the top PA suppliers will have CMOS PA technology in addition to GaAs.

It will take some time to work through the ramifications of the announcements in detail, but Qualcomm is the clearest beneficiary in the RF front end.