Summary

  • Alexandre Vogel and Cristel Pelsser found 17,435 antenna records shared by all four historical French operators in January 2026, equal to 4.45% of the study’s total.
  • Their inventory points to a practical test for connected vehicles and other critical M2M systems: check the physical radio path behind each operator before calling it redundancy.

Two mobile subscriptions can still send traffic toward the same antenna. The billing names split cleanly; the metal above the road may not. Alexandre Vogel, a UCLouvain PhD student researching vehicle communications, and his coauthor Cristel Pelsser set out to count that overlap in “Shared Antennas, Shared Risks,” a TMA 2026 paper.

The distinction in their study is useful. A shared site means operators use the same passive location infrastructure, such as a tower. A shared antenna is more specific: in France’s National Frequency Agency (ANFR) records, the same antenna identifier is associated with multiple operators. Several carriers on one tower can still use separate antennas. The common antenna is a more direct shared radio failure point.

The French inventory covers GSM, UMTS, LTE and 5G installations from Orange, SFR, Free and Bouygues Telecom. By January 2026, 50.71% of radio sites were shared by at least two operators; the study puts the 2018 baseline at 47%. Shared antennas reached 20% of the antenna total. The sharpest count is 17,435 records associated with all four operators, or 4.45% of the total.

That denominator covers the four historical operators in metropolitan France; overseas territories, broadcast installations and other installation owners sit outside it.

That concentration is not evenly spread across the map. The paper places shared antennas most heavily in moderately populated areas, around 100 inhabitants per square kilometre. Above 10,000 inhabitants per square kilometre they become marginal, while dense urban areas rely more on antennas dedicated to individual operators. For a vehicle or remote machine outside a city centre, two carrier profiles may therefore buy less geographic diversity than the labels suggest.

The records show infrastructure overlap, not outage history. The authors used public administrative data and did not actively measure operator networks. The paper reports no packet-loss comparison or observed failure rate. It also cannot resolve every common segment beyond the site and antenna records.

The paper’s French series runs from March 2018 through February 2026. ANFR’s public dataset page lists a later update, on 6 October 2026. A fresh join of the newer records would show whether 20% and 17,435 still describe the current inventory.

Vogel’s work makes the procurement question harder to dodge: multipath software can move traffic between operators, but it cannot manufacture physical diversity where both paths meet the same antenna.

Sources