Originally Posted by mastarpete
I stand corrected if that's the chipset used. I knew Samsung had been using SDRs I just was not aware that chips had become available to also dynamically handle the filtering.
Gentlemen, all phones operating in full duplex mode require band-specific RF duplexers to separate the uplink and downlink frequencies and route the antenna to and from the receiver and transmit PA respectively. These are essentially paired RF filters. Duplexers serve the additional purpose of blocking out of band interferers including harmonics generated by the phone transmitting on other bands. Additional SAW and BAW filters are still required in the receive chain in some cases to block interference as well.
E-UTRA bands 1 through 32 are FDD bands and require duplexers. B12 requires its own duplexer. A tunable duplexer that can operate over several of the 700 MHz E-UTRA bands might be possible in the future, but for now a phone that can operate in LTE mode on AT&T (B17), Verizon (B13), US Cellular etc.(B12) requires multiple duplexers.
A phone operating in "All LTE bands" would require an unworkable number of duplexers. As a result, LTE phones are operator and region specific with respect to LTE, and right now it takes at least three SKUs to cover the main population regions and LTE operators across the world. The radio chipset is the same, but not the duplexers and usually not the RF power amps. Some phones will not operate on the right frequencies for LTE on some carrier networks without hardware changes.