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AT&T and Verizon postpone 5G services due to possible interference


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US carriers AT&T and Verizon have voluntarily postponed the launch of their new 5G services until possible interference between aircraft navigation systems and control towers with 5G signals, which operate at a close frequency, is clarified. In the case of AT&T, 5G services were to start on December 5, which will now be done at least a month later, following the request of the authorities, while Verizon, which was to start them during the first quarter of 2022, has indicated that the work continues as planned. For these operators, the delay is a problem, especially if uncertainty continues and new postponements are requested, because T-Mobile US continues to gain 5G customers at its expense in the United States.


The FAA, the federal aviation authority that depends on the US Department of Transportation, and the FCC, the telecommunications regulatory body in the United States, have jointly requested mobile operators to suspend, for the time being, 5G services that They could start from December 5, as specified in the auction ended at the end of February, in which the new frequencies for 5G services were granted and for which nearly 100 billion dollars were paid in total.


AT&T has accepted the recommendation of the US authorities for now to delay one month, until January 5, the launch of its new 5G services. Verizon had announced a few weeks ago that it would start its 5G services during the first quarter of 2022, so it has not had to decide anything. You have simply assured that you will continue with the installation of the antennas.

Auction 107, with licenses between 3.7 and 3.98 GHz, consists of two parts; the first of which reaches up to 3.8 GHz and should be released on December 5, without interference problems in this case

The problem, as it has now emerged, is that the FAA has always objected that the frequencies of the so-called C band, between 3.7 and 3.98 GHz, granted in the auction ended on February 24, Auction 107, may interfere with the signals of altimeters and other aircraft navigation devices, which operate at frequencies close to 4.2 and 4.4 GHz. For the FAA, the margin of safety that has been left, which is at least 200 MHz, does not prevent interference between spurious signals beyond 4 GHz from 5G antennas and that can cause misreading in aircraft navigation systems.


The use of part of the C band for 5G signals was already a good headache for the former officials of the FCC, chaired by Republican Ajit Pai, because the band was occupied and granted in perpetuity by communications satellites that emitted signals. of TV. In the end, after much discussion, it was decided to cede the frequencies for 5G services and compensate the licensed satellite companies with nearly $ 14 billion, apart from locating their services on other frequencies, a process that has taken almost two years.


For this reason, the 5G services tendered could not start before next December 5, a year after the auction began and which ended on February 24 with a record amount, after 97 rounds, of 80.9 billion dollars. Verizon paid $ 45 billion for the frequencies it chose, while AT&T paid $ 23 billion, plus its share of the relocation costs. Verizon and AT&T, which were the operators that bid the most because they needed the frequencies most urgently. Other operators also came, mainly T-Mobile US and Dish Networks, although they were not so needy because they had frequencies in lower bands.


The FCC auction 107 began on December 8, 2020 and ended on February 17, with the winners being announced on February 24 and the licenses being officially granted, and after having paid, on July 23, with the new president. of the FCC in office, the Democrat Jessica Rosenworcel since the beginning of the year, after the previous FCC chairman had left with the victory of the president of the United States Joe Biden.


Coincidentally, President Biden appointed Rosenworcel as president of the FCC on October 26, a few days before the entire interference conflict was known, but the position has to be ratified by the Senate to be effective. Rosenworcel is a strong supporter of net neutrality and she wants to impose the majority of the three Democratic members of the FCC’s five total, an issue that Republicans have strongly opposed since Trump abolished it.


The still acting president of the FCC will now have to deal with the problem of alleged interference with 5G signals and who knows if the issue will make it even more difficult to take over the final position of president of the FCC, which must be done before end of the year. The whole issue of auction 107 and the relocation of satellite operators was approved by the former Republican president, after multiple discussions within the US Administration, because she was already busy. But in the end, this solution was chosen due to the urgent need to have more spectrum for 5G services and it will be Rosenworcel who will have to finalize this inherited matter.

Serious notice from the FAA

Since last August, just after auction 107 licenses were officially granted, representatives of the FCC and the FAA have held weekly meetings to try to approximate positions on the conflict of possible interference; even, according to sources consulted by The Wall Street Journal, which was the one who first aired the case, the White House has intervened as a mediator. According to Reuters, the FAA held a lengthy meeting with the aviation industry on the subject on October 14.


The FAA, which has insisted for several years about the danger of interference between 5G signals and those of airplanes, wanted an official resolution to be passed with immediate effect to limit the use by aircraft pilots of certain systems of automatic navigation to reduce the possibility of interference as much as possible. This resolution, however, remains blocked. The call for auction 107 already indicated that the necessary security systems would be introduced in the new frequencies so that they would not cause interference.


The conflict was precipitated last Tuesday, when the FAA published a special informative bulletin in which it “recommended altimeter manufacturers, aircraft manufacturers and operators to voluntarily provide federal authorities with specific information on the design of altimeters and their functionalities, specifically in the use of altimeters on airplanes so that their equipment can be verified and verified ”.

At the moment, another auction is being completed in the United States, the 110, with frequencies between 3.45 and 3.55 GHz, which had not been considered to be used for 5G because it was exclusively used by the military

The results of these tasks, the bulletin added, would be made available to civil aviation authorities and spectrum regulators, and it was already clarified in the bulletin introduction that the FAA was collaborating with the FCC and NTIA, the national agency. of information and telecommunications, “to assess the need for mitigation [of the signals] beyond the actions recommended by this special newsletter.”


Last Wednesday, the day after the FAA bulletin, operators AT&T and Verizon announced that they had agreed to delay the deployment of 5G services, scheduled by AT&T for December 5, to collaborate with the FAA to solve the problem. on the potential interference with key communications systems on airplanes. Already in the afternoon of Wednesday, the FCC and the FAA issued a joint statement in which they confirmed that they had asked the two operators for a voluntary pause in the introduction of 5G services.

An indeterminate wait for results

The journalistic information published speaks of the voluntary pause of one month, in principle until January 5, 2022, because in the granting of auction 107 it is expressly stated that the new frequencies can be put into operation as of December 5, 2021. But in no document does it say when the altimeters and communication systems may be evaluated or the implementation of supposed systems to mitigate interference or limit the functions of the pilots mentioned in the FAA bulletin.


Several experts, such as Harold Felds or Blain Levin, acknowledge that the delay of a month is not very important, although for AT&T it is a chore because it had everything ready to boost its 5G services just before Christmas, including a promotional campaign. The question is whether the delay will continue for several more weeks or perhaps even months, because then the damage to AT&T, and later to Verizon, can be very significant, says Levin of New Street Research.


The main beneficiary of all this mess is T-Mobile US, because it is already offering 5G services in much of the country thanks to the licenses it had and those obtained with the acquisition of the mobile operator Sprint, a merger process that was much discussed. In its day, with the firm opposition of Verizon and AT&T (the 5G service of T-Mobile US offers good 5G coverage, but little speed, because it works at low frequencies).


Verizon and AT&T seem convinced that a month can resolve the conflict or, at least, that they can move forward. Otherwise, they could request millionaire compensation for each day of delay, because the licensing has been official since July, when the auction amounts were paid.


The CTIA, the mobile industry lobby group, has been quick to send the FCC an electronic letter stating that “almost 40 countries have already adopted rules and have deployed hundreds of thousands of C-band base stations to similar frequencies and similar power levels as 5G signals in the United States and, in some cases, near aviation operations.


The arguments used by the CTIA are exaggerated, because very few countries use “similar” frequencies. In the European Union, the average frequencies used for 5G range between 3.4 and 3.8 GHz. In Spain, for example, the frequencies assigned for now range from 3.4 to 3.6 GHz, although they are planned in a future 3.6 to 3.8 GHz. In Germany, 3.4 to 3.7 GHz have been granted and in France, Italy and Finland they reach 3.8 GHz, but in no case up to 3.9 GHz as in the United States, although it does in some other countries such as Japan and in very few areas.

Auction 107 flexible, in two phases

In reality, some experts don’t quite see that the potential interference problem is as imminent as the FAA claims. AT&T reported last Wednesday that “at the request of the Ministry of Transportation, we have voluntarily agreed to postpone Phase 1 of the C-band deployments for one month, until January 5, to continue working in good faith with the FCC and FAA to understand the problems exposed by the FAA ”.


The key to this release is in “Phase 1”. Because, in reality, auction 107 contains, from the beginning, two phases or periods of implementation. Certainly, the 300 MHz of the lower part of the C band, the one between 3.7 and 3.98 MHz, which is the one used by satellite operators and assigned the upper 200 MHz, were certainly auctioned at the same time. from 4 to 4.2 MHz (after compensation for your rights). But the auction included the availability of these 300 MHz in two different time phases.


In a first phase, 120 MHz of spectrum between 3.7 and 3.82 GHz would be released, which would become available in 46 of the main 50 partial economic areas (PEA) of the United States on December 5, 2021, as make clear the bases of the auction 107. In a second phase, the auction rules continue to say, the other 120 MHz of the lower part of the spectrum would be released, from 3.82 to 4 GHz in the rest of partial economic areas and the entire process would be completed on the 5th. December 2023; therefore one year after the completion of the first phase.


In the table below, from the FCC, five sub-blocks of 20 MHz between 3.7 and 3.8 GHz are specified, which are those of the first phase that now, on December 5, should be cleared for their use for 5G signals, and release a year later another five 20 MHz blocks between 3.8 and 3.9 GHz, as well as another four 20 MHz blocks between 3 and 3.98 GHz, reserving 20 GHz of safeguard and for other satellite uses between 4 and 4.2 GHz.

In the lower chart from the Aerospace Industries Association (AIA), it is specified that interference with helicopter signals “starts” in the 3.75 GHz band, but that interference with commercial aircraft “starts” in the 3.95 GHz band, as the FAA also says and nobody disputes. The signal conflict, at least for commercial aircraft, is between 3.95 GHz and 3.98 GHz of the auctioned by the FCC plus, obviously, the security zone that you want to assign, or the protection systems potential interference.

In the first phase of the auction 107 of the FCC, which reaches up to 3.82 GHz and which is the one that would have been put into operation on December 5, there should not be, therefore, any conflict of interference with the airplanes commercial, because the signals are separated by more than 120 MHz; if anything, the problem could be with the helicopter signals.


To resolve the most contentious issue, that of commercial aircraft, an additional year would be available to find a solution that would satisfy all parties. The uncertainty would thus be transferred to the second phase of the auction. What is not fully understood are the reasons that have led to encompass the two phases in one, as if on December 5, 2022, 4 GHz were already reached when they reached 3.82 GHz.


The next thirty days will be decisive in seeking a solution to the conflict, although it seems that for another year it is not serious. The AT&T operator assures that it has granted the month of grace requested by the authorities “in good faith”, but it is clear that as of January 5 it will demand that the recommendations of the authorities to delay the start-up cease (they are recommendations because the authorities are clear that they cannot demand it without creating new conflicts of interest, since the licenses were officially granted.

New auction to have more spectrum

All this mess is due to the lack of sufficient spectrum in the United States for 5G services in the most suitable band, around 3.5 GHz. A first alternative envisioned was to go to the upper part of the spectrum, beyond the 12 GHz, in the so-called millimeter waves, which for several years were widely promoted in the United States to overcome the problem they had.


Millimeter waves, which offer higher speed but very little coverage radius and are also very sensitive to any obstacles in their path, have not finished working, at least for the daily use of 5G services. In addition, in its day the United States meteorological service raised the cry in the sky because the signals could interfere with the satellites that predict the weather, but it came to nothing because it does not have enough strength to impose its arguments.


Verizon made a big bet on millimeter waves and acquired a large portfolio of licenses throughout the country, but had to give up and take a large part of the licenses auctioned at the beginning of the year. Now, both Verizon and AT&T have also bid strongly in the auction that began a few weeks ago, the 110, and is about to conclude. In auction 110, licenses are granted in the 3.45 to 3.55 GHz band, but of limited and shared use, because they are partially occupied by the United States Ministry of Defense for their exclusive use and they have assigned a part.


Auction 110 started a few weeks ago and at first it was feared that it would have to be canceled because the minimum reserve amount, set by the FCC at 14.7 billion dollars, would not be reached, since AT&T left the auction after a few rounds because it already had its licensing needs covered, as did Verizon and T-Mobile US. But in the following days the bids were encouraged again and now, nearing completion, they have already exceeded 20,000 million dollars. Now it would only be necessary for the military to put new objections to the flexible use of this portion of the spectrum that they had granted for exclusive use that, not by chance, is the most precious part for the use of 5G.