4G/LTE - Non 3GPP Access
Non-3GPP Based Technology
In the past, most of the technologies implemented and commericalized are based on 3GPP specification. Meaning there are explictely defined specification first and then chipset maker/UE maker implement those features based on 3GPP specification. But recently I see the requirement in the market or from network operators are going even faster than formalization of 3GPP specification. So quite often I see some advanced chipset maker and UE makers are working on a lot of projects that is not even described in the 3GPP specification. When I say '3GPP' in this case, it means 3GPP 'TS' specification. There may be something going on in 3GPP at the level of discussion/forum or even at the level of 'TR' (Technical Report).
Followings are some of the features/technologies that belongs to this category as of my writing (Aug 2014)
Dual SIM/Multi SIM
U-LTE (LTE in Unlicensed Spectrum)
SON (Self Organizing Network)
You may not agree that I call SON as 'Non 3GPP based technology' because you might have heard about this for so many years and you might have beeing testing some of SON feature. I agree that some of the component technology that can be a 'PART' of SON like ANR, but SON as a fully integrated technology has not reached 'TS' level specitication. Even the latest 3GPP document 36.902 is 'TR', not 'TS'.