the Access Point Blog

Can Single Channel Really Work?

By Richard Watson

By Rich Watson — Product Marketing — Meru has been the lone-wolf for a number of years with regard to supporting single channel architecture[1]. The major Wi-Fi players have been neigh saying Meru by framing our offerings as “proprietary” and laying claims that Meru “transgressed the spirit and intent, if not the letter, of the IEEE 802.11 standard.” Yes, we admit Meru that has taken a different path to deliver Wi-Fi products to the enterprise and selected vertical markets, but quality and reliability have always been a guiding principle in our design. Some have wondered how this approach can even work at all; well, it does.

Since the founding of Meru, one design approach has guided our product development: maximize the wireless experience while minimizing the network management overhead. Deployment of traditional Wi-Fi networks can be complex, requiring site surveys and optimizing the network configuration to best match the target facilities layout. Not only is this tedious and expensive, but if a network extension to the network is required, often the whole process must be repeated all over again! It was from observing this struggle that Meru decided to build a product that simplified IT deployment and management jobs, while at the same time providing an exemplary Wi-Fi user experience.

A single channel Wi-Fi network presents a unique face to the wireless clients: the whole network appears to be a single, pervasive access point. This approach results in some powerful benefits for the client. Since the network appears as a single access point, the client’s authentication only needs to occur once, when they enter the network. From that point on, the client is also relieved of the responsibility of managing access point to access point roams as these are automatically performed by the network itself. This behavior supports excellent VoIP over Wi-Fi with voice quality that rivals hardwired telephones.

But, what about mitigating the co-channel interference (a typical question from our competitors)? Good point! First, let’s clear the air. No one, Meru or anyone else, can eliminate the co-channel interference; only merely mitigate it in a meaningful way.  In this context, Meru has found a way to develop Wi-Fi Alliance certified products (therefore standards compliant) and successfully sell worldwide into hospitals, schools/universities, hotels, arenas, stadiums, luxury liners, retail and business offices. Meru continues to demonstrate growth in our targeted vertical markets and successfully deliver Wi-Fi products that work in all kinds of scenarios. But, how does single channel work?

The Meru success lies in approaching product delivery from several angles. One major contributing factor is Meru operates the access points at full power which provides the largest coverage footprint possible. With this fact, we can deploy access points much further way from each other as to minimize the coverage overlap (domain of interference) while maximizing the coverage. In most networks, this means that each access point may be in a co-coverage area of a small number of other access points where co-channel interference must be addressed. There is also a natural randomness in the transmit/receive operations of the clients on the network that have a benign avoidance of collision or interference. Meru has optimized its algorithms over a decade and delivers a high quality and reliable product to the market place. The fact that today’s wireless networks are in the megabit per second range means that clients can get on and off the network, freeing up more bandwidth that existed in a slower network technology. 802.11n with 3×3:3ss links can provide 450 Mbps raw data rate which can satisfy most of the fastest and bandwidth hungry applications with room to spare.

Single channel will really come into its own with 802.11ac. Touted as the “Gigabit” radio, out the gate this standard has the capability of supporting 1.3 Gbps per radio running 3×3:3ss links. Wow! This will push Ethernet to the wall. The increased data rate is due primarily to the doubling of the channel width from 40 MHz to 80 MHz. Doubling the size of the channel is both a blessing and a curse (to some). With a fixed amount of spectrum, wider channels mean fewer channels with which to plan your network. Best case scenarios in North America, there are only four 80 MHz channels which is barely doable with the traditional multiple-channel schema. Worst case, without access to DFS spectrum, there are only two 80 MHz channels available. A traditional deployment scheme doesn’t work with only two channels; however, a single channel scheme will work just fine!

Attempts to deploy 802.11ac using only 40 MHz sized channels results in networks capable of supporting only 600 Mbps on a 3×3:3ss link. 40% short of the 1 Gbps! Being able to support a full 80 MHz channel pervasively throughout a wireless network places Meru in a unique position in today’s market place. Additionally, being capable of supporting a single channel layer affords Meru the benefit of supporting multiple single channel layers – or just channel layering. This allows Meru to make the most of the RF spectrum and maximize client capacity at the same time – unique in the Wi-Fi market place!

Ultimately, the answer to “does single channel work?” comes from the fact that Meru has sold thousands and thousands of customers worldwide in a variety of market segments where they have voted with their money because of their excellent experiences. The answer is YES! And it looks like this technology will take the lead in making 802.11ac successful in the market place.

[1] Now, Extricom and Ubiquiti are companies that offer a single channel based product

Categories: Industry Insights, Products.
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