Inside the MBAN frequency battle

Today I was copied on one of the industry petitions for frequency spectrum, specifically that of Philips. The FCC has asked for comments on the proposed spectrum allocation, and Philips is one of the companies that responded.

While the industry would like the whole 2360-2400 MHz band given over to 1-milliwatt devices in hospitals, they are willing to settle on just 10 MHz of spectrum for in-home use.

The problem, as Philips sees it, is AMT, aeronautical and military users of the spectrum who depend upon it for telemetry data.

"The record indicates scant use by AMT of the 2390-2395 MHz portion of the spectrum," the document states. "The spectrum should therefore be joined with 2395-2400 MHz to allow the 10 MHz to be used by MBAN in-home and mobile devices with up to 20 milliwatts" of power output.

The idea in a nutshell. There are lots of WiFi radios out there, chips tuned to a slightly lower frequency can thus be had cheaply, but WiFi is crowded, especially within hospitals. Allocating the full 40MHz to very low power use within hospitals gives those locations means there is minimal interference with other spectrum uses and enough bandwidth to do as much intensive data collection as required.

Any device used in a hospital would have to be extensively regulated, which will be reflected in the price, so Philips sees two markets developing, one industry and one consumer.

A system sold for the consumer market, collecting things like blood pressure, blood sugar, and/or heart rate data, would be a different kettle of fish. It would use a smaller slice of spectrum, with WiFi or cellular systems as backhaul. It would also be transmitting much less frequently than a hospital system -- just 2% of the time against 25%, Philips estimates.

By using a narrower frequency band, and by locating that band close to (but not within) frequencies already used for transmitting voice and data, a large consumer market could develop, Philips believes, in conjunction with smart phone systems like the iPhone and Android.

Consumer devices would only "call" these larger systems after a basic analysis of incoming data shows an emergency may be developing. There could easily be an app for that.

A two-chip radio board-let worn on the wrist, across the chest, or even implanted would use its cellular system for emergency calls and WiFi on a schedule, transmitting a day or week's data to a larger storage system, clearing its cache.

"Imagine your cordless phone at home – you do not need to spend any time or cost managing the spectrum for the phone – we aim to the same for MBANs (Medical Body Area Networks)," a Philips spokesman explained. "I do not see any additional cost if this is done correctly."

Opening this to the whole market of consumer medical and hospital device makers should assure someone does it effectively, even cost-effectively.