There seems to be a basic misunderstanding about RNP . RNP is not "new technology", or a navigation system as such. It is a concept based on the probablility of navigation containment within an area of airspace, or for a defined procedure. By stating a required RNP value, the air navigation service provider is saying that the aircraft systems and the ground navigation infrastructure combined must meet the navigation accuracy defined by the RNP.
A piece of airspace supported by an airborne ADF and a single NDB could be assigned an RNP value - just rather a large one.
In practice, RNP is closely associated with RNAV systems since it is these that provide the "extra" accuracy when combined with the ground navigation infrastructure. As an example, domestic enroute operations would probably be assigned RNP4 (4=4NM). Non-precision approaches are RNP0.3. Most RNAV systems can be certified to a given RNP value, will display their capability at any given time, and operate to a given RNP.