From what I could read so far as long as the aircraft is compliant the operator may file RLatSM tracks:
Eligibility:
-Authorized required navigation performance 4 (RNP 4)
-ADS-C (automated dependent surveillance-contact) and CPDLC (controller pilot data link communication) equipped and, where applicable, authorized
-Operating required communications, navigation and surveillance (CNS) systems
http://www.nats.aero/wp-content/uplo...e-Briefing.pdf
See also here, starting page 325:
http://www.faa.gov/air_traffic/publi...15_16_ntap.pdf