Overcoming the ultimate Wi-Fi challenge

Have you ever wondered why adding a new wireless access point (AP) in a busy user environment doesn't always improve the Wi-Fi performance?

Are you still surprised when your video conference is interrupted by buffering?

In a school with an AP in every classroom, why do students still struggle with slow download speeds?

And, why you break out in a cold sweat at the mere thought of providing Wi-Fi access for hundreds of users at a large conference?

These are some of the most common scenarios you've probably faced with wireless deployments across a range of user environments.

But what's causing these widespread issues?

It's called co-channel-interference. This is when you have multiple APs in the same wireless channel and they interfere with each other, reducing performance. It happens on every network, but it's something that you probably don't know how much it reduces performance.

We all love high-quality video streaming and lag-free mobile learning made possible by today's next-gen 802.11ac APs. But the advantages of this latest technology come at a price — they have fewer channels, which means more APs need to use the same channel. And this means more co-channel interference. With the next generation technology that we know is coming in the foreseeable future, there will be even fewer channels, so the problem's only going to get worse.

Until recently, no vendor tested its wireless APs to see how they handled overlapping channel configuration with other APs. Why? Simply, because no one had a solution to address the problem.

Is there simple way to avoid co-channel interference? Reducing transmission power is an obvious option, but this may result in worse coverage and dead zones. So, in order to have good coverage, high performance and reduced co-channel interference, there really needs to be a technical breakthrough.

We have the answer and it's our smart antenna technology.

ZyXEL smart antennas eliminate interference and deliver Wi-Fi performance up to 100% better than other industry-leading manufacturers. How do we know this? Because we put our APs head-to-head with the best in the business.

Get ready for the co-channel interference challenge!

To validate our claims, we now have an independent performance testing report from the Networking Group at the University of Brescia, leading experts in the field of wireless network performance. To put the technology through its paces, they compared 802.11ac Wi-Fi APs equipped with and without smart antenna technology from four leading networking brands: Aruba, Cisco, Ruckus, and ZyXEL. Two were equipped with smart antennas, and all featured three spatial streams and support for 2.4GHz and 5GHz radio bands.

The devices under test

Vendor
Model Name
PHY
Spatial Streams
Radio
Smart Antenna
Aruba
AP-225 802.11ac 3 x 3:3 dual radio N
Cisco
2702i 802.11ac 3 x 4:3 dual radio N
Ruckus
R700 802.11ac 3 x 3:3 dual radio Y
ZyXEL
WAC6503D-S 802.11ac 3 x 3:3 dual radio Y

Key findings:

Coverage test

This test recreates a single AP installation in an open room, similar to a loft or office space. Ten clients are located in nearby rooms with different reflective barriers impacting signal strength.

Smart antenna technology delivers more throughput than non-smart antenna. And within smart antenna, ZyXEL is number one by delivering the best throughput through the most locations on both 2.4 and 5GHz.

Figure 1. The deployment of the coverage test
Figure 1. The deployment of the coverage test
Figure 1. The deployment of the coverage test
Position
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
Aruba
431.82 373.06 288.62 248.83 77.13 125.73 103.56 105.32 37.97 7.94
Cisco
367.35 453.71 247.34 258.82 72.46 108.78 76.88 95.87 28.33 10.26
Ruckus
371.99 377.58 299.09 284.10 125.03 162.15 122.34 128.92 76.83 21.61
ZyXEL
497.61 493.11 291.38 333.04 99.76 149.11 141.35 144.24 55.59 21.96
Table 1. The result at 5GHz
Position
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
Aruba
110.59 120.77 112.56 109.12 41.00 47.74 60.28 50.70 46.95 26.62
Cisco
111.55 116.42 102.90 99.88 72.05 49.06 64.96 46.16 37.75 25.31
Ruckus
115.32 117.92 111.24 106.20 0.16 65.37 35.22 36.61 64.88 45.62
ZyXEL
111.90 119.44 116.97 117.14 85.03 80.84 80.67 63.94 61.25 40.92
Table 2. The result at 2.4G

Co-channel interference test

The co-channel interference test set out to show how smart-antenna technology can easily and effectively overcome this problem.

Two APs from each vendor were installed in two rooms. Both APs were set up in the same channel so that the signals overlapped. Where they overlapped, we had co-channel interference.

When within the area that the signal overlapped, ZyXEL Smart Antenna APs were able to consistently deliver the best throughput. Specifically, an average of 75% more throughput than Aruba.

Figure 2. The deployment of co-channel interference test
Figure 2. Example of deployment of co-channel interference test: Each AP with 4 associated clients, and change 8 deployments of client locations to get comprehensive, unbiased test result.
Figure 2. Example of deployment of co-channel interference test:
Each AP with 4 associated clients, and change 8 deployments of client locations to get comprehensive, unbiased test result.
Figure 3. The result of the co-channel interference test (1)
Figure 3. The result of the co-channel interference test (1)
Figure 3. The result of the co-channel interference test (1)

To push the performance envelope further, testers increased the smart antenna AP transmission power by four times to 23dBm. This created even more overlapping signal areas, and reduced dead zones, but put additional strain on the APs. This environment let us measure the full benefit delivered by the smart antenna.

As shown in figure 4, the ZyXEL Smart Antenna APs won all critical scenarios with a performance advantage of 12%-28% over the second-ranked Cisco AP. Even Ruckus, with its smart antenna technology, failed to keep up under extreme conditions.

Figure 4. The result of the co-channel interference test (2)
Figure 4. The result of the co-channel interference test (2)
Figure 4. The result of the co-channel interference test (2)

Conclusion

ZyXEL has proven that it is the number one vendor when it comes to tackling co-channel interference. Due to its superior design and smart antenna technology, ZyXEL has outperformed all other vendors in a range of scenario's we see every day.

ZyXEL's Smart Antenna AP outperformed the competition, dealt with co-channel interference the best, delivered the highest throughput, and proved itself as the number one option in challenging environments.