cdma polar transmitter

Since a lot of time polar transmitter (power amplifier) publications are available and proposed for cellular handsets, e.g. from Tropian (www.tropian.com) for non-constant envelope standards.
But this architecture has not established. As far as I see, only few EDGE PAs are based on this, but no CDMA. What are the reasons? And what are the AM-to-PM problems?

Should be no big difference implementing polar modulation for CDMA compare to EDGE. Is true, now are a lot of applications for GSM-EDGE, and a few manufacturers claims that some of their systems support in this moment Polar Modulation (RFMD, Skyworks, AD).
In CDMA the bandwidth of the external loop, which compensate AM to AM (as an AM modulator), is higher compare to EDGE (due to higher symbol rate in CDMA).
AM to PM of the PA is compensated using a PM component as an RF drive waveform at the PA input.
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