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Why Wi-Fi Stinks—and How to Fix It

Ask consumers in the developed world about their household Wi-Fi connection and they’ll likely tell you that lately it seems to be getting worse, not better. Some might even say, “It stinks!” Even the residents of the White House have Wi-Fi problems. In an interview with the BBC just before Super Bowl 50, First Lady Michelle Obama complained, “It can be a little sketchy. The girls are just irritated by it.”

The White House, along with homes inhabited by more than 80 percent of the United States and 50 percent of the worldwide population, are in urban areas where Wi-Fi connections are steadily getting worse. The reason would appear to be obvious: There are many more people—and things—using Wi-Fi than a decade ago, and the numbers continue to grow. Today, 6.4 billion connected devices are in use around the globe. By 2020, that will mushroom to 20.8 billion—that’s 2.8 mobile devices for every person on Earth. So certainly the wireless highways through which Wi-Fi traffic moves have gotten and will continue to get more crowded.

But the reason for the virtual traffic jam is not as straightforward as simply having more vehicles to accommodate: The roads themselves are causing conflicts. And the situation has been made worse by three changes in the market.

First, not only is every house on your block likely to have a router but quite a few will have more than one, and many communities are also served by public Wi-Fi networks. Second, an increased demand for speed demands wider virtual lanes on the Wi-Fi highway, which means there will be fewer of them. And finally, cellular operators are dumping traffic into the Wi-Fi spectrum—to stay with the roadway analogy, imagine all the people who had been commuting by train suddenly taking to private cars.

Here’s how Wi-Fi has become a victim of its own success—and what engineers can do to improve things.

Wi-Fi operates in what is known as the unlicensed spectrum. That is, though the Federal Communications Commission (FCC) generally demands licenses to use the airwaves in the United States, and national spectrum regulators like Japan’s Ministry of Internal Affairs and Communications do the same elsewhere, the regulators leave some frequency bands relatively open. Users do have to comply with technical requirements, including power limits, but they do not have to apply for specific permission. There are several of these bands out there, but home Wi-Fi networks primarily operate in the 2.4-gigahertz and 5-GHz bands, because these are the only available parts of the radio spectrum that have the range and bandwidth needed. The 2.4-GHz band works the best here: It easily penetrates walls and furniture, and signals generally travel farther at the same power level as they do in the 5-GHz band.

In the United States, in the 2.4-GHz band, the FCC has authorized roughly 80 megahertz for Wi-Fi use. The channels operating there under the IEEE 802.11 standard are 20 or 22 MHz wide, so you can fit in only three nonoverlapping channels: 1, 6, and 11. The situation is only slightly different in Europe, where 13 channels allow for still just three nonoverlapping channels at a time, and in Japan, where 14 channels allow for four nonoverlapping channels.