FCC tweaks two-year-old MBAN rules.
Two years ago the Commission authorized Medical Body Area Network (MBAN) devices to operate in the 2360-2400 MHz region, immediately below the heavily-used unlicensed band that houses Bluetooth, and most Wi-Fi, along with many other applications. (We reported on that here, if you want to refresh your recollection.) MBANs relay information about a medical patient’s condition to data-gathering terminals, allowing patients to get up and move about without dragging wires behind or pushing carts full of equipment in front of them.
In August the FCC acted on petitions for reconsideration of its MBAN rules, making a few tweaks which mostly relaxed restrictions on MBAN use. The Commission also adopted procedures for frequency coordination and selection of an MBAN coordinator. That Second Report and Order has now been published in the Federal Register, so now we know that the tweaks will take effect as of November 5, 2014 except for Section 95.1225(c) (which requires the MBAN frequency coordinator to operate as a nonprofit entity and to provide information on a nondiscriminatory basis and to pass its database along to any eventual successor coordinator). That rule, which was added on reconsideration, must first be run past the Office of Management and Budget pursuant to the Paperwork Reduction Act.
MBANs are authorized in the 2360-2390 and 2390-2400 MHz bands. Because these frequencies are shared with aircraft flight test stations, their use is restricted to low-power signals within a confined area, and they may not operate within line of sight of a flight test receive station. The wider band, 2360-2390 MHz, may be used only indoors and only in health care facilities. The 2390-2400 MHz band may be used anywhere.
MBANs are licensed by rule, which means that they have a little more status than unlicensed devices, but users do not require individual licenses. Users of the 2360-2390 MHz band must nevertheless register their locations with a frequency coordinator, to make sure that they are not within line of sight of a flight test station. Registration also insures that, if interference is caused, it can be tracked down and eliminated.
On reconsideration, the FCC tightened its rules for the 2360-2390 MHz band to minimize the possibility of interference, authorizing that band for use only in medical facilities that can hold patients for more than 24 hours, which pretty much means real hospitals. While this change reduces the number of facilities that can use the larger band, the FCC notes that the industry standard accommodates up to 18 patients in the smaller 2390-2400 MHz band, which should be sufficient for smaller medical facilities. The FCC has also clarified that its restriction on outdoor antenna height to three feet above ground does not apply to the 2390-2400 MHz band.
MBANs are networks of transceivers made up of a central programmer/controller and one or more body-worn devices. Each network must be independent; networks may not “talk” to each other using MBAN radio channels. In the 2360-2390 MHz band, body-worn devices must not transmit unless they are in radio communication with a controller and receive instructions from the controller allowing them to operate. That may sound harsh, if not dangerous; but a body monitor is of little or no value if its data can’t reach a controller, so the threat comes from loss of the link to the controller, not shutdown of the body monitor.
On reconsideration, the FCC eased up on restrictions on communication among MBAN units. Controllers in separate networks may now exchange information, as long as the information is limited to coordinating spectrum use by assigning channels and time slots, not transferring medical data. Likewise, body-worn units, previously restricted to communicating with controllers, may now coordinate directly among themselves within a single network. That allows a unit that goes out of service (for instance, if a sleeping patient rolls over, causing the link to the controller to be lost) to instruct another body-worn device to take over monitoring chores. In the future, the FCC may allow even more flexibility in how MBAN devices communicate with one another and are configured into networks.
The requirement to register with a coordinator will now include not only devices which actually operate in the 2360-2390 MHz band but also devices which will initially operate only in the 2390-2400 MHz band but have 2360-2390 MHz capability that might be used in the future. Not every separate component must be separately registered – recognizing that body-worn device technology is now so advanced that these devices are numerous, often replaced, and even disposable, the Commission has determined that a single registration may cover a network consisting of many devices.
The MBAN coordinator will be expected to keep a registry of MBANs, determine whether a proposed MBAN location is within line of sight of an flight test receiving station and thus prohibited, and provide information about who is registered in the event of an interference complaint. Initially, there will be only one MBAN coordinator, to be selected by the FCC’s Office of Engineering and Technology. It remains to be seen whether more than one organization will seek the contract, which will be for 10 years. The coordinator may contract with an outside firm for technical expertise, as long as the arrangements are disclosed to the FCC. It may charge fees for its services and may pass through any charges it incurs for services it obtains from the flight test coordinator. If coordination fees get too high, or if other reasons suggest that competition is needed, the FCC may authorize multiple coordinators, as it has done in other radio services.
Will we soon see patients walking around hospital corridors with antennas sticking out all over? Probably not, since 2360-2400 MHz band devices use very small antennas. But the prospects are now much better for patients to move about, even if they are so seriously ill that their condition must be constantly monitored by devices that will keep records of what their body is doing and will sound an alarm if immediate medical attention is needed.
