60 GHz Powers Up

The 57-64 GHz band, which stretches across 7 GHz, has the widest swath of spectrum anywhere in the FCC rules, notes the Communications Law Blog.

Back in 2008, carriers paid $19 billion at auction for a mere 52 MHz of the 700 MHz band; at those same prices, the 57-64 GHz band would go for 2.6 quadrillion dollars – about 30 times the total economy of the world, figures their newsletter.

But the (free) unlicensed 60 GHz band has its downsides. All frequencies in these upper reaches of the spectrum propagate poorly. The 57-64 GHz region is worse than most.

Previously, the FCC’s rules governing unlicensed operations in this band allowed about 10 watts of power. You could link nearby buildings on a campus, but not much else.

An industry group asked for a power increase to help combat the oxygen fog. That was in 2004. The FCC thought about it for three years and issued a Notice of Proposed Rulemaking in 2007. Now, six years later still, it has finally acted on the request (pdf).

The FCC has now raised the power limits in this band by a factor of almost 16,000. But only extremely directional outdoor antennas having beamwidths of about half a degree or less are allowed this much power. Less directional antennas have to dial the power back.

The FCC envisions the new rules providing wireless connectivity over distances up to a mile at data rates of 7 Gbps. The spectrum is highly suitable as a backhaul alternative for LTE networks in urban areas, says the FCC.

Still, signals in the 57–64 GHz region are severely attenuated. Even over relatively short distances, rain fade and power absorption by oxygen molecules is a serious problem. The 70 and 80 GHz band actually has better propagation.

The upcoming IEEE 802.11ad (WiGig) standard will also use the 60 GHz spectrum, and deliver up to 7 Gb/s. But those networks will likely be confined to indoors and not penetrate walls.

Related DailyWireless articles on the Millimeter Band include; Wireless 100 Gbps — Over 100 Miles?, DragonWave: More Bits per Buck, 70GHz Radios, NextPhase + GigaBeam Deliver SoCal Biz Nets, EZ Wireless Deploys 60 GHz for DOJ, FiberTower to Backhaul Sprint WiMAX, XO Expands Backhaul, SkyNet for UAVs, 70GHz Radios, Superbowl Unwired, UK Frees Millimeter Band, 60 GHz Radios, 60GHz Comes Home, 60 Ghz Long Shot and 10 Gig Wireless?.

Posted by Sam Churchill on .

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