Time for a New Spectrum Plan

The spectrum in this country is a mess. And this is not necessarily a complaint against the FCC because much of the mess was not foreseeable. But the FCC has contributed at least some to the mess and if we are going to be able to march into the future we need to start from scratch and come up with a new plan.

Why is this needed? It’s from the sheer volume of devices and uses that we see coming for wireless spectrum. The spectrum that the wireless carriers are using today is already inadequate for the data that they are selling to customers. The cellular companies are only making it because a large percentage of the wireless data is being handed off to WiFi today. But what happens when Wifi gets too busy or if there are just too many devices?

As of early 2013 there were over half a billion internet connected devices in the US. This is something that ISPs can count, so we know that is fairly accurate. And the number of devices being connected is growing really quickly. We are not device nuts in my house and our usage is pretty normal. And we have a PC, a laptop, a tablet, a reader and two cell phones connected to wireless. And I am contemplating adding the TV and putting in a new burglar alarm system which would easily double our devices overnight.

A huge number of devices are counting on WiFi to work adequately to handle everything that is needed. But we are headed for a time when WiFi is going to be higher power and capable of carrying a lot more data, and with that comes the risk that the WiFi waves will get saturated in urban and suburban environments. If every home has a gigabit router running full blast a lot of the bandwidth is going to get cancelled out by interference.

What everybody seems to forget, and which has already been seen in the past with other public spectrum, is that every frequency has physical limits. And our giant conversion to the Internet of Things will come to a screeching halt if we ask more of the existing spectrum than it can physically handle.

So let’s jump back to the FCC and the way it has handled spectrum. Nobody saw the upcoming boom in wireless data two decades ago. Three decades ago the smartest experts in the country were still predicting that cell phones would be a market failure. But for the last decade we have known what was coming – and the use is wireless devices is coming faster than anybody expected, due in part to the success of smartphones. But we are on the edge of the Internet of Things needing gigantic bandwidth which will make cell phone data usage look tiny.

One thing the FCC has done that hurts the way we use the data is to chop almost every usable spectrum into a number of small channels. There are advantages to this in that different users can grab different discrete channels without interfering with other users, but the downside to small channels is that any given channel doesn’t carry much data. So one thing we need is some usable spectrum with broader channels.

The other way we can get out of the spectrum pinch is to reallocate more spectrum to wireless data and then let devices roam over a large range of spectrum. With software defined radios we now have chips that are capable of using a wide variety of spectrum and can change on the fly. So a smart way to move into the future is to widen the spectrum available to our wireless devices. If one spectrum is busy in a given local area the radios can find something else that will work.

Anybody who has ever visited a football stadium knows what it’s like when spectrum gets full. Practically nobody can get a connection and everybody is frustrated. If we are not careful, every downtown and suburban housing area is going to look like a stadium in terms of frequency usage, and nobody is going to be happy. We need to fix the spectrum mess and have a plan for a transition before we get to that condition. And it’s going to be here a lot sooner than anybody hopes.

FCC Makes Changes to 60 GHz Spectrum

United States radio spectrum frequency allocat...

United States radio spectrum frequency allocations chart as of 2003 (Photo credit: Wikipedia)

On August 12, 2013 the FCC, in [ET Docket No 07-113] amended the outdoor use for the 60 GHz spectrum. The changes were prompted by the industry to make the spectrum more useful. This spectrum is more commonly known as the millimeter spectrum, meaning it has a very short wavelength and operates between 57 GHz and 64 GHz. Radios at high frequencies like this have very short antennae which are typically built into the unit.

The spectrum is used today in two applications, a) as outdoor short-range point-to-point systems used in place of fiber, such as connecting two adjacent buildings, and b) as in-building transmission of high-speed data between devices for functions such as transmitting uncompressed high-definition (HD) video between devices like blu-ray recorders, cameras, laptops and HD televisions.

The new rules modify the outside usage to increase power and thus increase the distance of the signal. The FCC is allowing an increase in emissions from 40 dBm to 82 dBm which will increase the outdoor distance for the spectrum up to about 1 mile. The order further eliminates the need for outside units to send an identifying signal, which now makes this into an unlicensed application. This equipment would be available to be used by anybody, with the caveat that it cannot interfere with existing in-building uses of the spectrum.

One of the uses of these radios is that multiple beams can be sent from the same antenna site due to the very tight confinement of the beams. One of the drawbacks of this spectrum is it is susceptible to interference from heavy rain, which is a big factor in limiting the distance.

Radios in this spectrum can deliver up to 7 Gbps of ethernet (minus some for overheads) and so this is intended an alternative to fiber drops to buildings needed less bandwidth than that limit. A typical use for this might be to connect to multiple buildings in a campus or office park environment rather than having to build fiber. The FCC sees this mostly as a technology to be used to serve businesses, probably due to the cost of the radios involved.

Under the new rules the power allowed by a given radio is limited to the precision of the beam created by that radio. Very precise radios can use full power (and get more distance) while the power and distance are limited for less precise radios.

The FCC also sees this is an alternative for backhaul to 4G cellular sites, although the one mile limitation is a rather short one. Most 4G sites that are already within a mile of fiber have largely been connected.

This technology will have a limited use, but there will be cases where using these radios could be cheaper than installing fiber and/or dealing with inside wiring issues in large buildings. I see the most likely use of these radios to get to buildings in crowded urban environments where the cost of leasing fiber or entrance facilities can be significant.

The 60 GHz spectrum has also been allowed for indoor use for a number of years. The 60GHz band when used indoors has a lot of limitations related to both cost and technical issues. The technical limitations are 60 GHz must be line-of-sight and the spectrum doesn’t go through walls. The transmitters are also very power consumptive and require big metal heat sinks and high-speed fans for cooling. Even if a cost effective 60 GHz solution where to be available tomorrow battery operated devices would need a car battery to power them.

One issue that doesn’t get much play is the nature of the 60 GHz RF emissions. 60 GHz can radiate up to 10 Watts with the spectrum mask currently in place for indoor operation. People are already concerned about the 500mW from a cell phone and WiFI and it is a concern in a home environment to have constant radiation at 10 Watts of RF energy. That’s potentially 1/10 the power of a microwave oven radiated in your house and around your family all of the time.

Maybe at some point in the distant future there may be reasonable applications for indoor use of 60 GHz in some vertical niche market, but not for years to come.