Last week, a 3GPP 5G RAN (Radio Access Network) workshop took place in Phoenix, Arizona for interested companies to voice their opinions about requirements and potential implementations of Super High Frequency Air Interfaces between 6 GHz and 100 GHz. A summary can be found here as well as a number of very interesting presentations, it's well worth a look. There is one important thing, however, that is rarely mentioned, perhaps because it's implicitly understood: All transmissions over 6+ GHz radios will only reach devices a few meters away at best which means we have to say good bye to our current idea of what a cellular radio network is. Or, in other words, how do you bring such a radio close enough to devices, be they carried by humans, or be they machine type communication devices installed in fixed places or moving inside and outside of buildings?
Today it's already very difficult to drag a fiber to macro base stations covering hundreds of meters in diameter. So how is that going to work in the future? Electricity lines are dragged into the last corners of civilization but the business model for that is entirely different: It's not the electricity company doing that, it's the end user with an interest to have electricity for lighting and other things in all places not necessarily only for himself but also for others. Do we require a similar approach for 5G data networks as well, is there an alternative to such an approach, how can an end user provide connectivity for others and not be responsible for the data flowing over this connection and can an organization consisting of network operators and equipment manufactures actually define something like that? For me the answers to those questions are even more interesting than the details of future 6 GHz+ radio interfaces.
Obviously, answers to this can't be given by 3GPP RAN as they focus on air interface aspects. Instead, this is the task of 3GPP's System Architecture (SA) Group and they will have a first meeting on 5G (only) in December 2015. A joint workshop between SA and RAN is scheduled for the second half of 2016 according to the 3GPP tentative timeline for 5G. In other words, there's still quite some time to ponder these questions.