FCC Should Proceed with Care in Mandating Spectrum Sharing, Industry Says

"The Commission has often struggled to provide licensees with any meaningful enforcement mechanism to address harmful interference,” CTIA said. “From radar detectors to signal boosters, exclusive-use licensees have waged an uphill battle to remedy even well-documented incidents of harmful interference.” Problems caused by radar detectors demonstrates that once devices are deployed, “there is no effective way to remove these devices completely, even if operating unlawfully and causing harmful interference,” the wireless association said. The record also shows that the spectrum bands used by carriers are already densely used and that spectrum sensing technologies have proven inadequate to protect mobile services from harmful interference, it said. “The challenge in sensing mobile use is due in part to the multitude of signal types operating in CMRS bands, including CDMA, EVDO Rev. 0, EVDO Rev. A, GSM, TDMA, SMR/IDEN, EDGE, UMTS, HSDPA, HSUPA, HSPA+, LTE, and WiMAX,” CTIA said. As technology evolves, “mobile networks operate at lower power and a lower signal to noise ratio, making spectrum sensing that much more difficult."

PISC said many commenters agree that the commission should look at other areas where spectrum can be shared, similar to what will occur in the TV white spaces. “The combination of a transparent, real-time database and spectrum sensing is noted in several comments as a particularly powerful means to protect primary users while making unused spectrum capacity available for flexible, shared use,” the group said. PISC agreed with carriers that the CMRS bands are generally “intensively and efficiently” used. But “it is also important to make a distinction between licensed spectrum that is being used to serve the public interest and licensed spectrum that lies fallow,” the group said. The PISC comments were also signed by the New America Foundation and the Media Access Project.

Shared Spectrum Co. (SSC), which develops dynamic spectrum sharing technologies, said they show huge promise, allowing “more and better use of increasingly limited available spectrum.” The company noted that the Department of Defense is already using sharing technology in some military bands and that carriers and others are already “employing cognitive radio techniques and developing standards. Spectrum sensing “is a far more dynamic and efficacious technology than was suggested by some commenters,” SSC said: “Databases, geolocation, beacons, and policy-based controls” also can be employed. SSC encouraged the FCC to seek funds for wireless test beds and to help identify federal governments bands that are strong candidates for sharing. “Though we recognize the many concerns of commenters regarding interference, security, and spectrum sensing, it is only by moving forward with development and testing of [dynamic spectrum access] radios that these concerns can be addressed,” the company said.

AT&T said the FCC should “resist” calls for sharing in bands used by carriers and focus instead on making more spectrum available for wireless broadband. “Commercial mobile broadband network operators already deploy dynamic spectrum access techniques within their networks to more efficiently use the limited spectrum resources available to them,” AT&T said. Allowing third- party use of the mobile bands “could have a disastrous impact on the growth of mobile -- and on the larger U.S. economy,” the carrier said. “The record in this proceeding unequivocally demonstrates that third-party deployment of devices using dynamic spectrum technologies in licensed CMRS technologies would undermine existing and future use of these bands,” Verizon Wireless said, expressing similar concerns.

The Wireless Communications Association also stressed the need to protect carrier networks from interference. Carriers are “deploying the latest, most spectrally efficient technologies available,” WCA said. “These technologies are only getting better with the advent of new, heterogeneous network architectures that promise to deliver the fastest, most reliable wireless broadband services ever.”

NAB and a broadcast engineer asked the commission to protect TV stations in the proceeding, on which the association commented for the first time this week. The inquiry is a “good first step” for the regulator to “look more aggressively at technologies that might be better suited to helping address anticipated capacity issues on wireless networks than more disruptive means like spectrum reallocations,” the NAB said. In a nod to making carrier use of spectrum more efficient, without impinging on TV stations’ radio waves, NAB said other comments in the inquiry “identify new technologies that will vastly improve spectrum efficiency and are currently in late stages of development.” That “suggests that even more promising technologies will soon follow,” the association added.

NAB cited comments by Qualcomm on the company’s authorized shared access technology. The Cohen Dippell broadcast engineering firm said it backed a filing in the docket by the Telecommunications Industry Association. TIA talked about avoiding “one-size fits all” solutions. Such a strategy is “particularly critical in the dynamic spectrum access regarding the uncertainty of spectrum monitoring and the potential interference to existing users,” Cohen Dippell said. “A significant burden will be placed on the FCC and its staff to insure that this more agile regulatory approach has strict adherence observance by the various parties. Otherwise, the FCC will be drawn into a quagmire of unknown interference events.”