Return of the Jedi, fighting with tiny Dots and CPRI (light) sabre

Having previously foiled the dark plot of the “Empire”, let us look at what the Jedi knights at Ericsson are up to these days. They deserve the title of Jedi as for last 20+ years they have been busy keeping the order in our mobile galaxy by fighting at forefront against the evil plots of the “Empire” and other separatists.

Their recent innovation, the indoor small cell system, named “Dot”, has seen mixed reaction from friends and foes. Even though the architecture can be called the classical closed system from the radio heads, it looks way better than the “Hyper Dense HetNet” proposed by the Imperial army generals, I mean visionaries.

The Dot architecture can be considered an evolution of DAS and provides a much more scalable and cost effective system to overcome the indoor coverage and capacity issue dogging the mobile industry for over a decade. The separation of baseband and radio resources is an elegant solution to provide coverage at the right spots while economizing on the baseband and in turn the spectrum the most treasured asset in the mobile galaxy. One of the biggest advantage of this architecture is that the macro and the small layers are managed by a common baseband pool simplifying the interference management.

Dot system is a two tier architecture, the first leg is a CPRI connection (open but lot of proprietary stuff) between baseband and indoor radio control unit. The second leg is their recent innovation, RFoLAN. Here the digitized RF is sent over Cat 5/6/7 cables commonly deployed to provide Ethernet connectivity in buildings. Interference management in such a system is not a big issue as all of the remote radio heads operate through the common radio resource management at the centralized baseband unit.

The analogy to explain the difference between Dot and Hyper Dense HetNet approach would be to consider a typical mall, where the former approach would require a handful of Dots to enhance the coverage/capacity indoor, the latter would require that each of the shops have to deploy their own little femtos and open the access to everyone. The former approach seems much more plausible and manageable. The bonus is that very similar architecture would work for indoor and outdoor environment. The outdoor cousin of the Dot system is what is known as Centralized-RAN or Cloud-RAN and has seen a lot of interest from operators with fiber rich access networks. After all there is some benefit to eating fiber rich diet

So overall Jedi knights have made a good return (on investment of course). Next we will see how this architecture unfolds in the routing/switching (plumbing) realm. Stay tuned for the next dose of this epic saga …

Footnote: the views in this series of blog are my own personal opinions, no corporate kool-aid involved

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