There is considerable argument for and against TD-LTE Vs FDD-LTE. An excellent summary is available at: http://www.ascom.com/en/tems-fdd-lte-vs-td-lte-12.pdf
The salient points are:
TD-LTE is better suited for M2M where continuous up link and down link operations (simultaneously) are not needed.
Total spectrum in TDD - 1133 MHz (in 11 bands)
Total spectrum in FDD - 1658 MHz (in 25 bands)
Other considerations for TDD would be in terms of hand off under full mobility conditions.
It is not that Verizon and AT&T have deployed FDD LTE simply because of availability. It actually can show improvement over typical 3G service that are operated by them. If they chose the TD version (even later) for regular customers, it may actually look like a reversal since TD-LTE will not be able to match the data rates offered by FDD versions.
I would like to believe Qualcomm being a intellectual property base rather than a manufacturer; it will keep tabs on its designs that are by no means easy to tap.
Having said that, the vague temptation of doing chips in China continues to attract many.
I hope that Qualcomm does not repeat the same mistake as Motorola in the early '90s when it started giving away technology to China in the hope that in turn the Chinese Govt. would give Moto exclusive rights to Base Station infrastructure.
The Chinese played Motorola for a chump. The MOS Fab that Motorola had put up a in Tianjin was basically looted for technology.
We all know how Motorola, once leader in Cell phones, fell apart.
The scion of the Jacobs family ( QC ) is perhaps smarter than that of the Galvin family ( Moto ).
From a technical point of view this has always made sense. Qualcomm was the rebel outlier when CDMA was the challenger to GSM, but now that those two have converged China Mobile is the new troublemaker. In order to bring them in line the Chinese government has to be satisfied that converged TDD/FTE LTE meets their needs. The big question is whether or not they can control that network and monitor the traffic. All other issues are at best secondary.
Interesting story Rick, looks like China (with Qualcomm's help) will drive NG wireless standards...I think FDD/TD combo makes sense as spectrum is scare and you need all possible tricks to fill all wireless channels to full capacity...I presume FDD stands for Frequency Division Duplex and TD for Time Division Duplex. I wonder though why they dropped second D in TDD to make it TD while kept it in FDD (rather than make it FD)...Kris
Blog Make a Frequency Plan Tom Burke 17 comments When designing a printed circuit board, you should develop a frequency plan, something that can be easily overlooked. A frequency plan should be one of your first steps ...