We described the technology used in our new wireless test process in this article. Now it's time to get into the exact details of how we use the new testbed.
Our V8 process is similar to the V7 process in that it uses octoScope anechoic chambers to provide a repeatable RF controlled test environment. The V2 testbed used by the V8 process has a turntable, which plays a key role in the new process.
New SmallNetBuilder Wireless Testbed
The V8 process has been designed to address some weaknesses of the V7 process. Specifically:
- Small separation of DUT and chamber antennas
- Bias toward products with vertically polarized antennas
- The need to eyeball a "best" out of four test runs
- Inability to fully test AC1900 class products in 2.4 GHz
The V8 process uses the same attenuation settings for "Location" values that are used in some benchmarks for backward-compatibility with products tested with old open-air methods.
Key values for 2.4 GHz are shown in the plot below. Throughput at 0 dB attenuation is used for Maximum Wireless Throughput Ranking and throughput at 60 dB attenuation is used for Wireless Range Ranking in the Router and Wireless product Rankers.
octoBox MPE Test Location Attenuations - 2.4 GHz
Key 5 GHz values are shown in the plot below. Throughput at 0 dB attenuation is again used for Maximum Wireless Throughput Ranking and throughput at 39 dB attenuation is used for Wireless Range Ranking in the Router and Wireless product Rankers. Less attenuation is used for range ranking in 5 GHz vs. 2.4 GHz due to higher path loss at those frequencies.
octoBox MPE Test Location Attenuations - 5 GHz
All wireless router performance testing is done on the LAN side of a router under test so that the product's routing performance does not affect wireless performance results, i.e. the Ethernet client is connected to a router LAN port. Access points are tested using their Ethernet port.
The wireless router / AP under test (DUT) is centered on the upper test chamber turntable in both X and Y axes. If the DUT has external antennas, they are centered on the turntable. If the antennas are internal, the router body is centered. Distance from center of turntable to chamber antennas is 18 inches (45.72 cm).
Initial orientation (0°) is with the DUT front facing the chamber antennas. The photo below shows the 0° starting position for a NETGEAR R8000 Nighthawk X6 router, which has six external antennas arrayed along the sides of the product.
NETGEAR R8000 in Upper Test Chamber - "0 degree" Position
And here is an ASUS RT-AC68U in its starting test position. (The white object is an LED worklight removed during testing.) Power and Ethernet cables are routed to the DUT from above, to not interfere with DUT rotation.
ASUS RT-AC68U in Upper Test Chamber - "0 degree" Position
The router or AP under test is set as follows:
- Reset to factory defaults
- WPA2/AES security enabled
- 2.4 GHz band: 20 MHz bandwidth mode, Channel 6
- 5 GHz band: 40 MHz bandwidth mode for N devices, 80 MHz bandwidth mode for 802.11ac devices, Channel 153
We continue to use 20 MHz bandwidth mode for 2.4 GHz testing. Most environments have too many interfering networks for reliable 40 MHz operation.