Cell-free mMIMO Support in the O-RAN Architecture: A PHY Layer
Perspective for 5G and Beyond Networks
To keep supporting next-generation requirements, the radio access
infrastructure will increasingly densify. Cell-free (CF) network
architectures are emerging, combining dense deployments with extreme
flexibility in allocating resources to users. In parallel, the Open
Radio Access Networks (O-RAN) paradigm is transforming RAN towards an
open, intelligent, virtualized, and fully interoperable architecture.
This paradigm brings the needed flexibility and intelligent control
opportunities for CF networking. In this paper, we document the current
O-RAN terminology and contrast it with some common CF processing
approaches. We then discuss the main O-RAN innovations and research
challenges that remain to be solved.