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Reliability

A Better Wi-Fi Experience with Dual Channel Wi-Fi™

Luther Smith
Director, Wireless Technology

May 21, 2019

At least 15 percent of customer service calls are Wi-Fi related, ranging from poor connections to video playback issues, translating to more than $600 million in annual support costs for the cable industry (in North America alone). As the Wi-Fi industry looks for ways to increase speed, coverage and support for more devices in the Wi-Fi ecosystem, one critical element has been overlooked: the need to have the necessary airtime to send data to all end devices in a timely manner. Even with faster Wi-Fi connections, if there is no available airtime to send the data, the connection is useless. CableLabs realized this shortfall and addressed it with the development of Dual Channel Wi-Fi technology.

What Is Dual Channel Wi-Fi?

Dual Channel Wi-Fi delivers an efficient and more reliable wireless connection.

The wireless networking technology that we commonly refer to as Wi-Fi is based on the 802.11 standard developed by the Institute of Electrical and Electronics Engineers (IEEE). The 802.11 standard, in turn, has its origins in a 1985 ruling by the U.S. Federal Communications Commission (FCC) that made the Industrial Scientific Medical (ISM) unlicensed radio frequency bands available for public use.

Wi-Fi is often referred to as “polite” because it uses a procedure called Listen-Before-Talk (LBT). LBT is a contention-based protocol that requires data-transmitting devices to listen and wait for a given frequency band to be clear before sending data. If the device (access point [AP] or station) does not detect transmissions, it proceeds to send data. If the device does detect transmissions, it waits for a random period of time and listens again for a clear frequency or channel before commencing transmission.

Wi-Fi has become ubiquitous over the years and is the primary method by which we connect devices in the home, at work and in public places to reach the internet. Multiple Wi-Fi devices in a typical broadband home can cause contention for available frequencies. Dual Channel Wi-Fi addresses Wi-Fi congestion issues by providing one or more channels for downstream-only data in addition to the primary bi-directional channel. The primary channel is used for upstream and small downstream packets and the others channel(s) are used for large downstream and time-critical data, like video. By offering operators configurable tools to intelligently redirect Wi-Fi traffic, better air-time utilization is achieved for all traffic, resulting in fewer interruptions and a much better Wi-Fi experience for everyone.

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Benefits of Dual-Channel Wi-Fi

Dual Channel Wi-Fi benefits more than just downlink-only clients:

  • A better overall multi-user experience: As demonstrated in our performance testing, without Dual Channel Wi-Fi, tests using two standard Wi-Fi channels show issues with video streams, gameplay delays, download buffering and slower throughput to individual devices. By moving data off the standard Wi-Fi channel, it effectively clears traffic from the channel, allowing both the AP and other clients more opportunities to send data.
  • A radically improved multi-user experience: By virtually eliminating hesitation and pixilation of video delivery, Dual Channel Wi-Fi enables smooth gameplay without delays and faster overall delivery of data to both Dual Channel Wi-Fi and non-Dual Channel Wi-Fi devices. In our tests, depending on the application download speeds, data transfer speeds increased up to 12 times while airtime efficiency (by reducing the need for retransmissions) increased by 50 percent.
  • Reduction of downlink data packet errors and packet retries: The AP’s ability to send data to clients without contention interference has reduced downlink data packet errors and packet retries, resulting in a reduction in uplink retry messages. This, in turn, allows the AP to send more TCP segments at a time, further reducing the amount of uplink traffic.

These improvements in data delivery over the Wi-Fi network as a whole are an example of user experience improvements that can be achieved by technologies that complement the cable industry’s 10G initiative. As the cable industry drives towards faster speeds, lower latency and increased reliability, Dual Channel Wi-Fi helps ensure that those benefits are experienced all the way to end user devices.

Because Dual Channel Wi-Fi is not limited to one downlink-only data channel, deployments in venues such as stadiums, airports or outdoor arenas can also benefit. Dual Channel Wi-Fi’s configurable filters can selectively assign, move or remove devices from individual downlink-only data channels. The mechanism to determine which downlink-only channels that different devices should be assigned is open to vendor development. This ability will allow operators and vendors to perform load balancing across the downlink-only data channels. The result is the management of the network to ensure the best user experience.

Dual Channel Wi-Fi is compatible with all Wi-Fi releases, including Wi-Fi 6. Dual Channel Wi-Fi has been developed and tested on various AP and client platforms. These include RDK-B, RDK-V, Ubuntu, Windows, MacOS and OpenWrt, which was co-implemented by Edgewater Wireless. Both CableLabs and Edgewater Wireless are excited about the opportunity to improve Wi-Fi for users around the world and look forward to working with standards bodies, internet service providers and device manufacturers of video set-tops, streaming devices, laptops, tablets and gaming consoles.

For more information about Dual Channel Wi-Fi, test results and implementation guides, click below.


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