One of the first decisions that had to be made in defining an interoperability standard for ground equipment was what to use as a base, VITA 49 or eCPRI? Both are standards for the interface between RF equipment and RF signal processing, and each is favored by one of the two major markets for satellite connectivity.
In this corner: evolved Common Public Radio Interface (eCPRI) is the enhanced version of CPRI which is commonly used in telecom networks supporting LTE, evolved to support 5G requirements. Opposite is VITA 49, which is commonly used in and preferred by defense and government RF based systems. Defense is the single biggest market by far for satellite connectivity and 5G NTN is the next frontier in commercial markets, including consumer direct-to-device (D2D).
The decision on which to base the DIFI standard wasn’t as simple as today vs. tomorrow, however. Defense ministries around the world are the largest customers for commercial satcom, and they, too, are exploring applications for D2D. After examining the arguments on both sides, VITA vs. eCPRI, DIFI planners found that VITA 49 was the clear choice for several reasons.
As a result, it was easy to define a simple locked down version of VITA 49 of just ten pages that supported the basic Digital IF needs of the satellite industry. That simplicity and ease of implementation helped enable broad adoption.
The kicker, however, is that VITA 49 actually sacrifices nothing when it comes to supporting satellite’s ability to capitalize on 5G.
Here’s why: When you compare the network architectures of traditional satcom and milsatcom systems against 5G NTN terrestrial architectures, while the equipment in the processing chain must interoperate at the digital IF level, the networks themselves integrate at the IP level. As a result, it makes no difference if the satcom network uses DIFI while the terrestrial network uses eCPRI.
Isn’t it nice when standards actually work together?
