The FCC (News - Alert) is into spectrum sharing. The FCC’s 5gHz rule making, opened on Feb. 20, 2013, is perhaps the most significant spectrum sharing proceeding yet because of the complexity of issues it is tackling.
That involves opening up more unlicensed spectrum but protecting shared-such as defense radar, satellite up links, civilian weather radar, and the new ITS safety-critical, transportation vehicle to vehicle program. The spectrum proposed to be shared is used by NASA, DoD, NOAA, and Homeland Security for radar and for uses such as drone communications. Moreover, 802.11ac is being finalized by IEEE (News - Alert) for use in U-NII 5gHz bands.
Spectrum at 5gHz is used for Wi-Fi radios and a new IEEE 802.11ac standard, designed around 5gHz, is about to be released and should deliver what’s being called gigabit Wi-Fi. There are now more than 150,000 cable company Wi-Fi hotspots in the U.S. and an estimated 2 billion Wi-Fi devices worldwide. Cisco (News - Alert), a major proponent of Wi-Fi (last year Cisco brought Wi-Fi mesh networking software startup Meraki for $1.2 billion cash) supports the improvement for the 5gHz rules as a way to satisfy what is says is the “exploding demand for… the 802.11 family of Wi-Fi standards.”
One study determined that 300mHz of spectrum would create $100 billion in value through cost avoidance. FCC Commission Ajit Pai explained the significance of the proceeding and referred to the new use as Super Wi-Fi.
“What excites me,” Pai said “is that we are building on these past successes and using spectrum ideally suited for unlicensed use. The short-range propagation characteristics of 5gHz spectrum enable localized reuse with minimal risk of interference. The next-generation Wi-Fi standard, IEEE 802.11ac, will be finalized soon. Manufacturers are already building devices to work on 5gHz spectrum. And enhancing the contiguity and size of the 5gHz blocks contemplated in the item should allow wider channels for higher bandwidth transmissions. For example, a 160mHz-wide channel could deliver 1 gigabit of data per second. That’s Super Wi-Fi.”
In 1997, the FCC addressed spectrum sharing for unlicensed use in 5gHz spectrum bands creating 300mHz of unlicensed spectrum. The FCC worked at making 5gHz more efficient since 1998 using power limitations and radar sensing. If the radio senses radar pulses, it turns off. That’s very simple but more efficient than not using unused spectrum. On June 11, 1998, the FCC initiated a new innovative spectrum program proposing to allocate 75mHz of 5gHz spectrum (the equivalent of 12 TV channels) for dedicated short range communications. DSRC (emphasizing the D for dedicated) was spectrum dedicated for the U.S. DOT’s Intelligent Transportation Systems, which is important in lowering the number of fatalities on the road currently 270 deaths per weekend. Vehicles using 5gHz will automatically know when another vehicle is headed toward impact.
There are currently four IEEE U-NII spectrum bands generally using 802.11a/h/j/n. The new NPRM proposes adding two more U-NII bands. Apple (News - Alert) drove the FCC in 1997 in the direction of wireless networking for schools. The FCC first allocated three 5gHz bands for this unlicensed networking school-focused use and then added a fourth 5gHz band, the worldwide band, in 2003. Now, the FCC proposes adding a two new bands for a total of six bands.
The FCC hopes to solve the FAA radar interference issues, create more spectrum for broadband use from ineffectively managed 5gHz U-NII spectrum, and increase the amount 5gHz spectrum to match with bands allowed by other countries creating opportunities for manufactures to sell lower priced devices.
A neutral database can be used to coordinate power levels between the radios without requiring spectrum sensing in the devices. The databases can tell radios within tightly defined geographies to turn on or off, or to change channels based on the database information of other radios operating in the same geographies and same channels. The databases would operate to give priority to higher power (1W) radios over lower power (50mW) radios but at the same time allow lower power radios to occupy the bandwidth that is unused in a local geography by a higher power radio.
Barlow Keener (News - Alert) is the principal with Keener Law Group (www.keenerlawgroup.com) out of Boston.
Edited by Stefania Viscusi