Carriers Warn of Interference Risks from Deployable Aerial Communications

"To the extent the Commission is considering public safety spectrum for DACA use, it must ensure a robust interference protection regime,” CTIA said (http://xrl.us/bniafa). “Any framework must include prior and real-time coordination to prevent disrupting operating services being used by wireless subscribers or hindering critical restoration efforts. CTIA takes particular interest in any consideration of DACA use on CMRS spectrum, which would pose a multitude of challenges to wireless consumers.” The FCC is on the right track in asking about interference concerns in the NOI, the association said. “The Commission must ensure that DACA does not result in the unintended consequence of creating harmful interference to consumers utilizing the key services that have been maintained through a disaster and/or are being restored.”

Aerial systems “present numerous impediments to consistently and reliably replace commercial wireless networks following an emergency, even on a temporary basis,” AT&T said (http://xrl.us/bniaf9). “Supplementing commercial service with aerostats presents a major risk of significant interference to the parts of commercial networks that may remain operational during or are restored shortly after a disaster. Transmissions from aerostats would propagate into areas where operational base stations are located, interfering with [the] provider’s attempts to restore network operations in disaster areas and interfering with continuing operations adjacent to the disaster area. This interference risk cannot be eliminated.” AT&T said even if interference issues could be addressed, “such mitigation would require substantial and continuous coordination with commercial providers, redirecting limited resources away from terrestrial restoration efforts.” Rather than refocusing on the use of aerial architecture, the commission’s emphasis should be on “restoring terrestrial commercial networks as quickly as possible” as “the most effective means to serve the public during and following a disaster,” the carrier said.

"The use of aerial platforms presents technical, operational and interference obstacles that must be overcome prior to deployment on any frequencies, especially the commercial cellular bands,” Sprint said (http://xrl.us/bniaje). “Deploying aerial platforms following a disaster has limited utility for restoring service to subscribers and public safety personnel.” The NOI said DACA has been successfully deployed in various theaters in the absence of other infrastructure, Sprint noted. “While DACA may be a solution in areas that do not have existing infrastructure or where the infrastructure is completely destroyed, it can cause significant problems in areas where there is already a functioning network or where a network is in the process of being repaired."

DACA “could be a valuable means of restoring at least limited communications in the immediate aftermath of major disasters that destroy or disrupt existing terrestrial communications networks,” APCO said (http://xrl.us/bniah9). Use of DACA also poses risks, the group conceded. “Because of the potential for dangerous interference to systems unaffected by the disaster, use of DACA should be the last resort and used only when existing networks are inoperable and no other means of restoration is immediately available. Furthermore, to limit the potential for interference, DACA should only be deployed in the smallest area possible to address the emergency in question.” APCO said DACA could be used to replace damaged public safety systems as well as commercial networks.

Oceus Networks, doing a trial demonstration to assess the technological capabilities of DACA for emergency use, said its use should be further explored. “It has been nearly 11 years since the 9/11 attacks revealed inadequacies in the nation’s public safety communications infrastructure. Since that time, the U.S. has struggled with addressing these gaps in meeting first responder needs in a nationwide manner,” the company said (http://xrl.us/bniaiw). “Emergency communications will require multiple solutions to provide first responders the interoperable broadband communications needed to effectively respond to a disaster whether it is at the southern tip of Manhattan or in the Rocky Mountains, whether it be massive destruction caused by a man-made catalyst or a natural disaster."

The Unmanned Aviation Public Safety Association said the FCC should work with public agencies that fight wildfires to better understand how DACA could be used. “As wildland firefighting organizations explore the development and deployment of DACA technology, they will also provide an important opportunity to exercise day-to-day usage as outlined in the public safety communications interoperability continuum,” the group said (http://xrl.us/bniai8). “Day-to-day DACA usage for wildland firefighting that exercises all performance features can provide an important capacity and knowledge base for successfully using DACA to support large scale disaster response."

The Telecommunications Industry Association has members that manufacture DACA technologies and members that could be adversely affected by the potential interference caused by the technologies, the TIA said. It noted that DACA takes many forms. “TIA applauds the Commission’s consideration of DACA technology in improving its public safety goals but recommends the Commission carefully consider limiting DACA’s use to existing current public safety communication frequencies in order to avoid interference with commercial use and repairs,” the association said (http://xrl.us/bniajx). “In general, control of DACA platforms should be in the hands of local agencies that are in the best position to make potentially lifesaving decisions. The decision to implement DACA platforms should remain with these agencies as they are in the best position to evaluate the potential benefits and costs of implementation. DACA is a new and developing technology and should be monitored closely.”