Google Fiber has won accolades across the country for delivering gigabit speeds at prices that leave companies like Comcast grinding their teeth in fury as profit margins erode out from under them. One problem that Google and its rivals both face, however, is the expense of running fiber to each individual home. During Alphabet’s (Google’s parent company) annual shareholder meeting, CEO Eric Schmidt said that point-to-point connections can now be deployed via wireless at comparable speed to wired infrastructure, while being “cheaper than digging up your garden.”
Google has previously applied to the FCC for permission to test millimeter-wave wireless networking devices, which typically operate in the 60GHz band. The 802.11ad wireless networking standard also supports 60GHz frequencies, and it’s not a stretch to think that Google might want to build a network using that standard, especially since its already available in routers you can buy today.
It’s not clear, however, if 60GHz spectrum can be easily adapted to real-world conditions. The 60GHz spectrum is largely unlicensed and free from interference, but it’s also severely affected by attenuation from a number of sources. Part of the reason this has such an impact on 60GHz signals is because they resonate with the O2 molecule –otherwise known as “The stuff we breathe” and “21% of the atmosphere by volume.”
Graph by Wikipedia
60GHz signals are also subject to attenuation from rain, foliage, walls, and the human body. There are upsides to this situation, since it would allow for spectrum re-use over a relatively short area, but it’s difficult to see anyone building a cost-effective Wi-Fi network using 60GHz technology. The 802.11ad routers you can buy today use 2.4GHz, 5GHz, and 60GHz bands precisely so that the router can switch to 2.4GHz or 5GHz if you walk out of the room. 60GHz Wi-Fi also requires line-of-site transmission, which could mean Google Fiber would need specialized hardware in consumer’s houses in order to ensure a strong signal.
There are ways to deal with some of these problems, such as using a higher-power transmitter, or installing backup equipment in the 5GHz or 2.4GHz bands that would kick in if the 60GHz signal became too weak and began to fail. The problem in these cases is that people would rapidly sour on the idea of Google Fiber if it turned out they weren’t getting the speeds they thought they paid for. Building more transmitters closer to their customers would also help the situation, but at a higher cost.
Research into the 60GHz band is still ongoing, but some of the problems facing it are intrinsic to the frequency and its characteristics. Better technology isn’t going to solve the line-of-sight problem or the rain fade issue.