Get Wi-Fi protocol (802.11a/b/g/n) programmatically

Question

Through WifiManager, my Android app can get a lot of details about Wi-Fi. However I fail to get protocol type like a/b/g/n. I have a client requirement to do that.

Answer 1

I don't believe this is possible to get in a clean manner. The protocols - a, b, g, n, etc - are actually human abstractions of the MAC and physical layer in networks. These are defined as their recognizable letters if they meet certain hardware specifications, both for the device and the network device.

After doing some digging, it seems that Windows phones are able to display this information. When digging into the manner of determining the protocol on Windows, I came across the desktop explanation as well as the Visual C++ implementation via enums. It seems that even the official Windows documentation relies on vendor-provided data and enumerated values, which would lead me to believe that they need to determine hardware specifications beyond what is likely exposed in the Android API.

If you want to determine the protocol yourself, you'll need to understand the link speed as well as the frequency, modulation, and bandwidth.

TL;DR

Likely not possible unless you are working with a rooted phone and can access the hardware specs directly.

Answer 2

You can partially deduce the protocol from the link speed

WifiManager.getConnectionInfo().getLinkSpeed()

By Wikipedia 802.11 protocols speed table you can tell if it is 802.11b, 802.11n or 802.11ag.
802.11n and 802.11ac full link speed tables

Link speeds of protocols 802.11a and 802.11g are the same, you can distinguish between them by the used frequency (5GHz or 2.4GHz) in the scan results.

Note that protocol can change during the connection, client and access point do negotiate protocols and speeds but they agree on a list and not on one specific speed.

I don't think there is a way to distinguish between 802.11n and 802.11ac in their overlapping speeds.