Verizon and AT&T have been forced to delay their ambitious and expensive plans to roll-out 5G networks in the C-band after the FCC and the Federal Aviation Administration (FAA) demanded a review of the plans, citing potential interference issues in the mid-band spectrum with aircraft signalling.
The regulatory bodies jointly issued a statement regarding their concerns about interference with the radio altimeters in both commercial aircraft and helicopters. The two operators — who between them spent about $69 billion in a fierce bidding war earlier this year for licenses to the 3.7 to 3.98 MHz spectrum range — have agreed to a four-week delay to the roll-out of 5G services. They had planned to start deploying the networks early December.
The activation date of the new networks is now scheduled for January 5th next year, allowing the FAA and FCC to assess the potential impact of any interference and rule on the issue. The FAA’s detailed Special Airworthiness Information Bulletin can be accessed here.
Amongst the numerous recommendations in the SAIB to both the altimeter suppliers and aircraft manufacturers is that they should collaborate and conduct testing and analysis into the effects of loss of function, and erroneous or misleading altimeter data from potential harmful interference caused by fundamental emissions in the 3700-3800 MHz and 3700- 3980 MHz bands, as well as spurious emissions in the 4200-4400MHz band, due to wireless broadband deployment.
Verizon alone spent $45.5 billion for the licenses in numerous markets throughout the U.S., which promises to offer significantly better capacity and throughputs for advanced services. The auction raised a staggering $81 billion.
A month’s delay would be a minor set-back for the carriers, but if the FAA and FCC investigations do find serious co-existence problems with safety equipment, notably during low-altitude operations, it would represent a major setback for both the operators and consumers.
Ahead of the spectrum auction, the FCC declared it did not consider there was any “significant” interference to aircraft operations following the deployment of 5G networks using the C-band, but subsequently several airline companies raised concerns about their impact on the radio altimeters. These operate in the 4.2 to 4.4 GHz bands.
The aviation industry was very much involved in the FCC’s C-band deliberations, and on several issues raised their concerns. The final document ruled that well-designed altimeter gear would not normally have interference problems, and that there should be a 220MHz guard band before the spectrum auction.
The organization that represents the interests of the wireless communications sector in the U.S., the NTIA, chimed in last week, stressing its members believe 5G networks can safely use C-band spectrum “without causing harmful interference to aviation equipment,” and cited numerous active 5G networks using this spectrum band in 40 countries.
The NTIA pointed out in a filing last week with FCC that some 40 countries “have already adopted rules and deployed hundreds of thousands of 5G base stations in the C-band at similar frequencies and similar power levels — and in some instances at closer proximity to aviation operations — than 5G will be in the U.S.
“None of these countries has reported any harmful interference with aviation equipment from these commercial deployments, as the FAA recently confirmed.”
The document also asserted “live flight testing confirms the C-band 5G operations coexist today with radio altimeter operations. Given the substantial discrepancies in what is purported in the RTCA Report (Radio Technical Commission for Aeronautics) as compared to the successful operation of 5G in dozens of countries today, it is no surprise that live flight testing has also confirmed the ability of wireless to coexist with radio altimeter operations.”
Analysts tracking the sector were generally surprised at the last minute development, and the two carriers’ ready acquiescence to the delay.
For instance, in a research note, Blair Levin at New Street Research, suggested the issue may prove to be less serious for the operators than some believe, since wide-scale deployments were never on the immediate cards. “In reality, C-band radios aren’t on many more than a handful of AT&T towers and will only get to about to about 10% of Verizon towers this year.”
He suggested that any short term delays would likely be incremental rather than game changing.
However, Levin posits that any long term delay would give T-Mobile a short-term network advantage. “Most of T-Mobile’s advantage stems from planning and deployment schedules that pre-dated this phase of the FAA/FCC dispute.”
T-Mobile, it needs stressing, is already well ahead of the other major carriers in this area, and has been busy deploying mid-band 2.5GHz for some time. It needed to spend much less on C-band spectrum, and none of the 100MHz in the biggest markets that is subject to the potential delays, since it already had access on 2.5 GHz for its 5G roll-out.
Indeed T-Mobile claims that over the past year it has managed to offer 180 million Americans services via its 2.5 GHz midband, with average speeds of 200 Mbps, and in some cases at higher data rates.
Levin also pointed out that “unless the White House clearly steps in to resolve the matter, the outcome is determined by the willingness of two separate institutions to inflict or accept pain.”
Last week, The Wall Street Journal reported that the U.S. Administration has in fact started mediating between the FCC and FAA to find a solution.