FCC Expands Part 95 MedRadio Rules to Allow Devices in 2360-2400 MHz Band
In a First Report and Order and a Further Notice of Proposed Rulemaking (ET 08-59) released on May 24, the FCC decided to expand the Part 95 Personal Radio Service rules to allow medical devices to operate on a secondary basis in the 2360-2400 MHz band. These devices -- called Medical Body Area Networks (MBAN) -- provide a way for health care facilities to monitor their patients via wireless networks. Because use of these frequencies will be on a secondary basis, MBAN stations will not be allowed to cause interference to -- and must accept interference from -- primary services, including radio amateurs who operate on a primary basis in the 2390-2395 MHz and 2395-2400 MHz bands.
In July 2006, the FCC released a Notice of Proposed Rulemaking and Notice of Inquiry and Order (NOI), regarding the use of the radio spectrum for advanced medical technologies. In December 2007, GE Healthcare filed ex parte comments in response, proposing that the band 2360-2400 MHz be allocated on a secondary basis for “Body Sensor Networks” (BSNs). In April 2008, the FCC put the proposal on Public Notice; the ARRL submitted comments, pointing out the potential incompatibility with amateur operations. Nevertheless, in June 2009, the FCC released a Notice of Proposed Rulemaking that also requested comments on possible alternatives, including 2300-2305 MHz. The ARRL followed up in October 2009 with additional comments.
“Even though the Amateur Radio Service retains its primary status at 2390-2400 MHz, it remains to be seen how the addition of a new secondary service in the band will work out in practice,” noted ARRL Chief Executive Officer David Sumner, K1ZZ. “In the past, the FCC has declined the ARRL’s request to raise the status of the Amateur Service at 2300-2305 MHz to primary, even though there is no other service to which this segment of the band is allocated. This is now the only portion of the 2300-2450 MHz band -- which at one time was available in its entirety to amateurs -- that is not encumbered by other spectrum occupants. We hope that in the future, the FCC will be receptive to making the Amateur Service primary in this narrow segment, in recognition of the reduced utility of the remainder of the band.”
In making the decision to allow these devices in the 2360-2400 MHz band, the FCC noted that the costs of permitting MBAN operation “are limited to the risk of increased interference, which we minimize by adopting rules to protect other licensed operations in these bands. We find that the risk of increased interference is minimal and is greatly outweighed by the benefits of the MBAN rules we adopt today.”
Sumner observed that with this decision, “the Commission has effectively taken 2360-2400 MHz off the table for consideration for commercial wireless broadband.”
How Does this Affect Amateur Radio?
MBAN operators in the 2390-2400 MHz band will have to account for radio amateurs, who are authorized on a primary basis in this spectrum. “Both Philips and GE Health Care assert that interference from MBAN devices to Amateur Radio is unlikely, citing factors such as the low transmission power and low duty cycle proposed for MBAN devices, as well as geographic separation and the frequency agility of MBAN devices,” the FCC pointed out in its comments. “The ARRL does not anticipate that an MBAN would cause ‘a significant amount of harmful interference’ to amateur users, but it cautions that some amateur operations -- such as weak signal communications that occur on a ‘completely unpredictable basis’ -- could receive interference.”
The FCC said it believed that MBAN devices can “successfully share the band with the Amateur Service. These frequencies are part of the larger ‘13 cm band’ in which Amateur Radio operators already share the adjacent 2400-2450 MHz portion of the band with low-powered equipment authorized under Part 15 of our rules. We expect that the Amateur Service will likewise be able to share the 2390-2400 MHz portion of the band with MBAN devices because the power limits for MBAN operations will be even lower than that allowed for the unlicensed equipment that operates in the 2400-2450 MHz range. We further believe that MBAN and amateur operations are highly unlikely to occur in close proximity to each other. An MBAN, which will use very low transmitted power levels compared to the Amateur Service, is not intended for mass market types of deployment, and instead will be used only under the direction of health care professionals.”
According to the FCC, the majority of MBAN operations in the 2390-2400 MHz band will be located indoors: “We envision that the most likely outdoor use will occur in ambulances or while patients are otherwise in transit, thus we do not believe that prolonged outdoor use in a single location is likely. In such a situation, any interference that might occur would likely be transitory in nature and would not seriously degrade, obstruct or repeatedly interrupt amateur operations and thus would not be considered harmful under our definition of harmful interference.”
The FCC also addressed the potential for interference from radio amateurs to the MBAN devices. The ARRL, in its October 2009 comments, stated that “amateur operation in the band is unpredictable” and that the “substantial power levels and exceptionally high antenna gain figures used by radio amateurs in the 2390-2400 MHz band will provide no reliability of MBANs in this segment whatsoever,” calling the results of such interference “potentially disastrous.” The FCC pointed out that MBAN proponents assert that “MBAN devices will have built-in capabilities, such as spectrum sensing techniques to detect in-band amateur signals and frequency agility capability to move MBAN transmissions to other available channels.”
As to the ARRL’s concerns about MBAN’s reliability and the risk presented by interference caused by amateur operation, GE Health Care acknowledged that “medical device manufacturers seeking to develop equipment consistent with the MBAN rules would need to build robust products in order to satisfy FDA requirements and to ensure customer acceptance,” but the FCC did not view that as a barrier to its efforts to develop and deploy MBAN devices.
“We find that factors such as the incorporation of established techniques to avoid interference into MBAN devices, the use of low duty cycles and the separation distances between MBAN devices and amateur operations that are likely to occur in real-world situations will minimize any potential for interference to MBAN devices from amateur users,” it explained. “In the unlikely event that an atypical scenario occurs where amateur operators do receive harmful interference from MBAN operations, we note that amateur operators would be entitled to protection from MBAN interference. MBAN operations will occur on a secondary basis and MBAN operators will thus be required to accept any interference they receive from primary amateur licensees operating in accordance with the rules.”