Last month, Mavenir Networks was granted a US patent for a Method and Apparatus for Flexible Fronthaul Physical Layer Split for Cloud Radio Access Networks. (US 10,886,976)

Well-known for their advocacy of open RAN networks and ORAN-compliant radios, Mavenir is a supplier to Dish Networks and Rakuten (both vociferously open-RAN), and has announced it will be in trials with Jio.

But curiously, ‘976 does not mention “open RAN” anywhere in its 50-odd pages, although there are multiple references to 3GPP.

Even more curious is something from Claim 1:

downlink (DL) antenna port mapping and DL precoding which are implemented in the RU; and
uplink (UL) antenna port mapping is implemented in the BBU.

The ORAN fronthaul design places digital beam-forming (DBF) for both uplink and downlink in the RU (not the baseband [BBU]), and DBF is where the mapping between layers (spatial streams) and antenna ports takes place. So the line about uplink mapping in the BBU would seem to break the ORAN model.

‘976 is explicitly about asymmetric uplink and downlink functional splits between hi- and low-PHY, and touts numerous advantages as it describes several examples. But every example would appear to be entirely incompatible with an ORAN-compliant fronthaul.

What gives?

One can only speculate. Is Mavenir thinking it can persuade the rest of the ORAN Alliance to expand the fronthaul spec to include some of its patented ideas? Not impossible, but from all reports WG4 is very unlikely to take up any fundamental changes to the fronthaul in the foreseeable future, even for massive MIMO.

Is Mavenir, “The Industry’s Only End-to-End Cloud-Native Network Software Provider for CSPs” (Mavenir), thinking that, once established as truly end-to-end with a radio ecosystem to go with it, they might be able to sell a premium tier of RAN that is not ORAN-compliant? Possibly license its version of fronthaul to radio OEMs that want to play in Mavenir-hosted networks?

Why not?

It might be a shrewd strategy. Become established as the top open-RAN-evangelizing end-to-end OEM, and then persuade operators to buy into a Mavenir-proprietary patent-protected fronthaul that they will gladly license to radio OEMs for a quite nominal fee. Even to Nokia.

But maybe Mavenir has something more prosaic in mind, like negotiations over licensing of essential patents from the competition, or even getting acquired. The ‘976 patent could play a role by getting in the way of a Nokia or an Ericsson as they fill out features in their own proprietary RAN offerings. Potentially a tricky business, given reports that Mavenir has been raiding its competition for engineers.