The ITU approved two new recommendations on synchronisation this weekend. G.8272.1 is the first “enhanced” clock specification aimed at meeting the requirements for 5G mobile infrastructure. The document specifies the enhanced PRTC (Primary Reference Time Clock), basically a very high accuracy GNSS timing receiver, capable of delivering time to within 30ns of UTC.

This is over three times more accurate than the previous generation PRTCs, which were capable of meeting 100ns. At least one major vendor has already announced a product meeting this standard, so this is clearly real technology.

The second recommendation released this weekend was in some ways a throwback to the old, “safe and secure” frequency world. G.8266 defines the requirements of the PTP grandmaster delivering frequency over PTP. You may ask “why?”, since all the other recommendations associated with using PTP for frequency were published four or five years ago. The release of G.8266 plugs a gap in that suite of recommendations, since there was no agreed set of performance criteria to evaluate the GM against. As such, the frequency recommendations are complete for now, until the enhanced clock specifications come along next year (e.g. the enhanced SyncE clock).