Here's a question for LTE Radio designers both on the network and the terminal side that I can't find a good answer for in the documents I have read on LTE so far: In the 3GPP E-UTRAN standards documents, both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) is defined. It is often said that the implementation of the two different modes is very similar. Other sources point out that LTE will first be deployed in bands assigned for use with FDD. So I wonder if TDD will have a similar fate as UMTS TDD, which was specified, but never used on a large scale!? From my point of view, LTE TDD will only get a real chance if it is part of the first release of base stations and terminals. So here is my question: Does anyone know if TDD mode is part of mobile devices from day 1 and if so which market TDD mode addresses?