  Radio access network (RAN) virtualization is gaining more and more ground and
expected to re-architect the next-generation cellular networks. Existing RAN
virtualization studies and solutions have mostly focused on sharing
communication capacity and tend to require the use of the same PHY and MAC
layers across network slices. This approach has not considered the scenarios
where different slices require different PHY and MAC layers, for instance, for
radically different services and for whole-stack research in wireless living
labs where novel PHY and MAC layers need to be deployed concurrently with
existing ones on the same physical infrastructure. To enable whole-stack
slicing where different PHY and MAC layers may be deployed in different slices,
we develop PV-RAN, the first open-source virtual RAN platform that enables the
sharing of the same SDR physical resources across multiple slices. Through API
Remoting, PV-RAN enables running paravirtualized instances of OpenAirInterface
(OAI) at different slices without requiring modifying OAI source code. PV-RAN
effectively leverages the inter-domain communication mechanisms of Xen to
transport time-sensitive I/Q samples via shared memory, making the
virtualization overhead in communication almost negligible. We conduct detailed
performance benchmarking of PV-RAN and demonstrate its low overhead and high
efficiency. We also integrate PV-RAN with the CyNet wireless living lab for
smart agriculture and transportation.
