LTE has a bit of a problem with voice and a number of different approaches exist to sail around this for the moment. While some network operators might have an inclination towards CS-Fallback (CSFB) to GSM and UMTS, others like Verizon have gone the dual radio approach, i.e. having two radios active at the same time, one for CDMA-1x and one for LTE. An example is the HTC Thunderbolt, that has two radio chips inside. For CDMA it uses a Qualcomm MSM-8655 and for LTE it uses a MDM-9600. For details see here. But it seems to two chip approach might not be necessary for much longer. In this whitepaper, Qualcomm states that "for LTE handsets, the 8960 modem enables [...] simultaneous CDMA voice and LTE data (SVLTE [Simultaneous Voice and LTE])". That certainly fixes issue requiring two baseband chips required in a CDMA/LTE smartphone. A potential solution for the GSM/LTE world as well?