Nokia Siemens Networks is the only major infrastructure provider opting not to join the VoLGA (Voice over LTE via Generic Access) Forum, which is working on a new spec to deliver circuit-switched voice and SMS services over LTE networks. Major vendors such as Ericsson, Alcatel-Lucent and Motorola are a part of the forum, but NSN said it is proposing a different approach for delivering voice services on top of the IP-based LTE network. It is calling the solution Fast Track Voice over LTE. Article