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Spatial Streams Decoded – The Difference Between 1×1 and 2×2 WiFi Radios

Multiple end-user devices connect to your WiFi network daily. Anything from phones, tablets, laptops, watches, and more! And one of the things you have noticed is that some devices perform better than others, even while they are located in the same place. Why is that? Well, one of the reasons some end-user devices perform better than others is “WiFi Spatial Streams”.

What is a Spatial Stream in WiFi?

WiFi spatial streaming is a transmission technique used in wireless communications to transmit or receive independent and separately coded data signals, so-called streams, by way of each of the multiple antennas available on end-user devices. Each spatial stream can carry a certain amount of data, and much like adding additional lanes to a road, multiple spatial streams allow for a WiFi device to transmit or receive more data simultaneously.

The number of spatial streams supported by an end-user device is normally represented using something like 1×1:1 or 2×2:2. As for what each of these numbers represents, let us take one of them apart. For example, on a device that supports 2×2:2:

• The first 4 represent the numbers of antennas used for transmitting (TX).
• The second 4 represents the number of antennas used for receiving (RX).
• The last 4 represent the number of spatial streams the device can handle at the same time.

Now you may be wondering how the number of spatial streams supported by an end-users WiFi device can affect performance. Is there really a big performance difference between a device that supports 1×1:1 and a device that supports 2×2:2? The answer is yes! Here is why:

The more antennas an end-user device has, the better it can hear WiFi signals in the air. Which translates into higher transmit and receive signal strengths. For example, let us say that you use a device that supports 2×2:2 to measure the signal strength in a conference room and you see a signal of -31 dBm. Well, if you try using a device that supports 1×1:1 to perform the same measurements your signal strength would be closer to -45 dBm, which is a lot weaker.

More antennas translate into higher upload and download speeds. Of course, the main reason for higher speeds is being able to use multiple antennas to transmit or receive in parallel (more data streams at the same time). Still, that is not the only reason, as mentioned above more antennas improve signal strength. This means the end-user device can connect at higher data rates, and thus achieve higher upload and download speeds.

Lastly, now that you understand how the number of WiFi spatial streams supported by an end-user device can impact performance, you may want to know how to identify the number of WiFi spatial streams supported by an end-user device. The easiest way to find this information is to use a tool like the EtherScope nXG or AirCheck G3 PRO, which can identify the number of spatial streams being used by both access points and end-user devices. Not only that, since both the AirCheck G3 Pro and EtherScope nXG have a 1×1:1 and a 2×2:2 radio, you could use them to determine how different types of end-user devices will perform on your network.

Author Bio –
Product Manager – Wireless

Julio Petrovitch is a product manager at NetAlly, plus a certified CWNA/CWAP/CWDP/CWSP. He’s worked with network design, testing and validation for more than 15 years. Throughout he’s career he has had the opportunity to work with multiple networking technologies, including POTS, DSL, Copper/Fiber Ethernet, Wi-Fi, Bluetooth, and BLE.