It’s been apparent for a few years that the 2.4 GHz band of WiFi is getting more crowded. The very thing that has made the spectrum so useful – the fact that it allows multiple users to share the spectrum at the same time – is now starting to make the spectrum unusable in a lot of situations.
Earlier this year Apple and Cisco issued a joint paper on best network practices for enterprises and said that “the use of the 2.4 GHz band is not considered suitable for use for any business and/or mission critical enterprise applications.” They recommend that businesses avoid the spectrum and instead use the 5 GHz spectrum band.
There are a number of problems with the spectrum. In 2014 the Wi-Fi Alliance said there were over 10 billion WiFi-enabled devices in the world with 2.3 billion new devices shipping each year. And big plans to use WiFi to connect IoT devices means that the number of new devices is going to continue to grow rapidly.
And while most of the devices sold today can work with both the 2.4 GHz and the 5 GHz spectrum, a huge percentage of devices are set to default to several channels of the 2.4 GHz spectrum. This is done so that the devices will work with older WiFi routers, but it ends up creating a huge pile of demand in only part of the spectrum. Many devices can be reset to other channels or to 5 GHz, but the average user doesn’t know how to make the change.
There is no doubt that the spectrum can get full. I was in St. Petersburg, Florida this past weekend and at one point I saw over twenty WiFi networks, all contending for the spectrum. The standard allows that each user on each of these networks will get a little slice of available bandwidth, which leads to the degradation of everyone using it in a local neighborhood. And in addition to those many networks I am sure there were many other devices trying to use the spectrum. The WiFi spectrum band is also filled with uses by Bluetooth devices, signals from video cameras and is one of the primary bands of interference emitted by microwave ovens.
We are an increasingly wireless society. It was only a decade or so ago where people were still wiring new homes with Category 5 cable so that the whole house could get broadband. But we’ve basically dropped the wires in favor of connecting everything through a few channels of WiFi. For those that in crowded areas like apartments, dorms, or within businesses, the sheer number of WiFi devices within a small area can be overwhelming.
I’m not sure there is any really good long-term solution. Right now there is a lot less contention in the 5 GHz band, but one can imagine that in less than a decade that it will also be just as full as the 2.5 GHz spectrum today. We just started using the 5 GHz spectrum in our home network and saw a noticeable improvement. But soon everybody will be using it as much as the 2.4 GHz spectrum. Certainly the FCC can put bandaids on WiFi by opening up new swaths of spectrum for public use. But each new band of spectrum used is going to quickly get filled.
The FCC is very aware of the issues with 2.4 GHz spectrum and several of the Commissioners are pushing for the use of 5.9 GHz spectrum as a new option for public spectrum. But this spectrum which has been called dedicated short-range communications service (DSRC) was set aside in 1999 for use by smart vehicles to communicate with each other to avoid collisions. Until recently the spectrum has barely been used, but with the rapid growth of driverless cars we are finally going to see a big demand for the spectrum – and one that we don’t want to muck up with other devices. I, for one, do not want my self-driving car to have to be competing for spectrum with smartphones and IoT sensors in order to make sure I don’t hit another car.
The FCC has a big challenge in front of them now because as busy as WiFi is today it could be vastly more in demand decades from now. At some point we may have to face the fact that there is just not enough spectrum that can be used openly by everybody – but when that happens we could stop seeing the amazing growth of technologies and developments that have been enabled by free public spectrum.