Transcript

WiFi and Bluetooth Testing Overview

In our previous test, we’ve been using the Bolt’s WiFi connection to verify that the Bolt was operating correctly under various conditions, and the connection’s been very solid. But we want to take a closer look at its WiFi and Bluetooth capabilities to make sure it’s operating correctly. They are both robust protocols and can appear to work well, even when there are problems. So we’re going to take a closer look to make sure it’s operating the way we expect.

To do that, we’re going to do these tests in the screen room where the Bolt is isolated and connected to one access point. This avoids interference from other devices. In our lab we have multiple access points and Bluetooth and WiFi hardware, and we want to get those out of the picture and just see how the Bolt itself is performing.

I’m gonna take off all my other devices that have WiFi and Bluetooth: Apple Watch, Fitbit, phone. So the only devices in the screen room that are using WiFi or Bluetooth are the Bolt, and we’re using a Seeker as an access point connected through the feedthrough port on the screen room. So the rest of the tests will be done in the screen room.

Screen Room Setup

We have a Bolt that is connected to a Seeker. We have a Seeker outside the screen room, and the Seeker’s WiFi connection goes through the feedthrough and is being broadcast with this antenna. So there’s a WiFi connection between the Bolt and the Seeker. The Bolt is the client and the Seeker is the access point.

To look in detail at the signals, we have two different devices. We have a USB-connected spectrum analyzer to look at the spectrum at 2.4 gigahertz and five gigahertz, and we also have a WiFi channel analyzer that is more specific to the WiFi protocol to see what’s happening at that protocol level. And then for Bluetooth, we’ll be using separate Bluetooth hardware in addition to the spectrum analyzer.

We’re gonna test the band edges to make sure that the connection is solid at each edge, and make sure the antenna is tuned correctly and there’s no other RF issues inside the Bolt, and also at the band center. These should all work very well because we have an almost direct connection. We have line of sight and we’re only a few feet apart.

2.4 Gigahertz Lower Band Edge (Channel 1)

We are now connected at 2.4 gigahertz in the lower band edge, so we’re in channel one, and this is a 20 megahertz band, and we have an excellent signal quality on the Bolt. The Bolt’s WiFi subsystem actually reports link quality, and that’s a combination of received signal strength and noise in that channel.

We’re going to do a speed test. I’m going to start a speed test on the Seeker. This will send data to the Bolt, and we can see on the spectrum analyzer that we are within the 20 megahertz band. As this data is transferred, there’s no leakage outside the band edge. And as it’s transmitting, again, we are on channel one, but it’s four channels wide because it’s four, five megahertz wide channels bonded together, and the Bolt is doing this correctly.

So we’re sending data back and forth from the Seeker to the Bolt, and during this test we are getting about 11 megabits per second, which is to be expected with this type of connection. So the Bolt WiFi system is working very well at the band edge. Next, we’ll test it in the band center.

2.4 Gigahertz Band Center (Channel 6)

We’ve now reconfigured the Seeker to use the center of the 2.4 gigahertz band. We’re at channel six, and we’re gonna run the speed test again. We see that we are now sending data continuously in the 20 megahertz wide band in the center of the 2.4 gigahertz. You can see on the waterfall graph that we’re sending a significant amount of data.

We’ll jump to the spectrum analyzer display to take a little bit closer look. And here we see we’re between 2.41 and about 2.45 megahertz, or gigahertz. So again, the Bolt is operating as expected and delivering us a good speed.

2.4 Gigahertz Upper Band Edge (Channel 11)

Now we’re on the other band edge. We’re on channel 11 at the upper end of the 2.4 gigahertz band, and we have reconnected the Bolt to the Seeker. Again, we have 70 out of 70 signal quality. We are going to run a speed test and generate some traffic to make sure that we stay in the band edge, and we are in that 20 megahertz band. We can see on the waterfall plot that that’s where we are staying.

I’m gonna run the test again to generate some more traffic. Again, we’re at about 10 to 11 megabits per second with this connection, which is normal. So the Bolt at 2.4 gigahertz is transferring data correctly on both band edges and in the center of the band as expected.

Five Gigahertz Lower Band Edge

Now we’re in the five gigahertz band and we’re starting at the left band edge, at the lowest frequency, and this is a 20 megahertz channel. We’re connected and we have a good signal strength. We’re at minus 48 DBM on the Bolt, and we are at minus 49 DBM on the Seeker, and our link quality is in the mid-60s out of 70. At five gigahertz, almost six gigahertz, it’s virtually impossible to have a perfect signal strength.

So let’s do the transfer test. We can see that we are transmitting data in that 20 megahertz band at the edge. If we go to the channel analyzer, we can see that we’re at the left edge of the band, and here the channels are 20 megahertz wide, not five megahertz wide, so we’re at 100% in band 36, the lowest five gigahertz channel.

We’ve completed the transfer test. Let’s run it and get some stats from that. We are sending data here, and we’re still in the correct section of the five gigahertz band. And we’re getting about 12 megabits per second, as expected for this connection.

Five Gigahertz Upper Band Edge (Channel 165)

Now we’re at the other end of the five gigahertz band. We’re at channel 165 at about 5.8 gigahertz. Let’s run a speed test and make sure that we are sending data in the correct section of the band. Here we can see that we are at the extreme edge here at channel 165. That’s the 100% utilization on that band.

Take a look at the spectrum, and here we can see as we are sending data, we are adhering to the hard band edge. This is the end of the five gigahertz band at 5.8 gigahertz roughly. And we are getting similar numbers as we got for the other band edge, roughly 11 to 12 megabits per second.

Conclusion

So the Bolt is working correctly at 2.4 gigahertz and at five gigahertz, at band edges and the band center. It is showing a really good WiFi performance.