  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.
