The VoLGA service resembles the 3GPP Generic Access Network (GAN). GAN provides a controller node - the GAN controller (GANC) - inserted between the IP access network (i.e., the EPS) and the 3GPP core network. The GAN provides an overlay access between the terminal and the CS core without requiring specific enhancements or support in the network it traverses.
The ITU has coined the term IMT Advanced to identify mobile systems whose capabilities go beyond those of IMT 2000. In order to meet this new challenge, 3GPPs Organizational Partners have agreed to widen 3GPPâ€™s scope to include systems beyond 3G. See blog on Advance LTE Requirements