Science

WiFi Traffic Management Algorithm

Visual representation of the 2.4 GHz WiFi frequency channels. Each channel is represented by a dotted half-circle representing 22 MHz of bandwidth. The half-circles representing the 3 front channels (1, 6, and 11) have solid outlines. The others overlap behind and between the front 3 channels except for channel 14 which only overlaps the edges of the 12th and 13th channels.
Visual representation of the 2.4 GHz WiFi frequency channels and how they overlap (22 MHz channels). Creative commons licensed image by Michael Gauthier on Wikimedia Commons.

Phys.org reports on a new algorithm developed by a doctoral student at École polytechnique fédérale de Lausanne (EPFL) that changes frequencies and bandwidth usage based on the type of data packets being sent and received. Many routers today are set by default to use channel 6 of the 2.4 GHz frequency which causes a build-up of WiFi traffic on that channel. The problem is that many other channels overlap and use much of the same frequencies. In fact, while there are 14 total channels made available in the 2.4 GHz range, many countries ban the use of some of those frequencies. In the United States (US) channels 12 through 14 are not able to be used yet are the ones with the greatest frequency gap between channels. In effect, because the frequency bands overlap you can argue that there are really only 3 available spaces to transmit data in the 2.4 GHz WiFi band.

Visual representation of the 2.4 GHz WiFi frequency channels. Each channel is represented by a dotted half-circle representing 22 MHz of bandwidth. The half-circles representing the 3 front channels (1, 6, and 11) have solid outlines. The others overlap behind and between the front 3 channels except for channel 14 which only overlaps the edges of the 12th and 13th channels.

Visual representation of the 2.4 GHz WiFi frequency channels and how they overlap (22 MHz channels). Creative commons licensed image by Michael Gauthier on Wikimedia Commons.

The graph above shows the frequency channels for the 2.4 GHz WiFi range and how the channels overlap. Most routers are set to channel 6 by default and while they may change channels depending on availability they generally pick a channel and stick with it. In addition, many routers will use up to 8 of these channels at the same time. The problem is that this rather small range gets filled up in areas where many routers are being run and essentially cause a traffic jam of data. The other problem is that because routers will often stick with a set channel other may actually be open and unused.

The new algorithm would determine the bandwidth requirements of the data being sent and received and would select an appropriate channel and width. It essentially removed the idea of “channels” and instead divvies up the available frequency range into “lanes.” Some of the lanes are specialized similar to having a carpool or bike lane. As an example, if all you did was check your e-mail and browse a few websites you don’t need much bandwidth. The new algorithm would utilize a small amount of bandwidth – say within channels 1 and 2 – for just website browsing and email. Videos such as Vimeo and YouTube, which require much more bandwidth, may get a large chunk of channels 6 through 10 to use, and the remaining could be used for various other purposes such as websites with larger images, chat programs, and cell-phone updates. It spreads out the use over the available bandwidth and specialized certain areas for things like low-bandwidth data such as web and email, cell-phone updates, and high-bandwidth videos. The developer claims that it could increase typical router throughput by up to seven times (7X).

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