In this landscape, it means a filing that claims a technical route across the disaggregated points of an O-RAN architecture — most commonly the open fronthaul interface between radio unit and distributed unit, the split 7.2 functional split, or the E1/F1 interfaces linking the centralized and distributed units. The search underlying this page combines O-RAN and open fronthaul terminology in the claims and description with IPC classes covering wireless network topology (H04W), digital transmission (H04L) and network-related radio configuration (H04W92). Filings that mention O-RAN only in passing, without claiming one of these interface points, generally fall outside this scope.

Samsung Electronics and its Beijing research affiliate co-file together and Samsung shows the only non-declining momentum in the latest tracked year among assignees in this dataset. Two Rakuten entities, Rakuten Mobile and Rakuten Symphony, form the strongest co-assignee pair historically with eight shared families, though both show no latest-year activity. Beyond these, the corpus of 76 families includes a long tail of single- or few-filing entrants, so leadership here is concentrated but not locked in by any one company.

The 2022 peak of 23 families lines up with the period when O-RAN Alliance specifications for fronthaul, E1 and F1 interfaces had matured enough for vendors to file concrete implementation claims rather than architectural placeholders. Filing activity since has not exceeded that level, which reads as the initial claim space filling in around the specification cycle. Because publication lags filing by roughly 18 months, the final one or two years of the trend will always look lower than they eventually turn out to be once more filings publish.

The smaller IPC categories in this dataset — AI-based network intelligence (G06N, 4 records), antenna-specific claims (H01Q, 4 records), and measurement or sensing classes (G01J, G01N, A61B, 2 each) — sit well below the dominant H04W/H04L/H04B cluster and suggest under-claimed intersections. Concretely, that means AI-assisted fronthaul scheduling, sensing-integrated split-7.2 signalling, and adaptation layers for non-O-RAN-compliant legacy RAN hardware. A first claim in any of these areas would face a much thinner prior-art base than a straightforward fronthaul or E1/F1 interface claim.

US20210243840A1, covering the fronthaul interface for advanced split-RAN systems, carries 45 citations within this corpus, well ahead of the next most-cited record at 17. That reflects its position as an early, broad filing in the category — later applicants cite it as a matter of course. Citation counts inside a searched corpus systematically favour older records, so a high count signals historical influence on the field's claim language rather than current commercial relevance.