CODEWITHSUNDEEP
javaandroid
JexSrs
JexSrs

Reputation: 155

How to find the frequency band of specified access point

I am using the following code to find all access points near to me.

We start the scanner with

registerReceiver(wifiReceiver, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
wifiManager.startScan();

and get the results using a BroadcastReceiver

BroadcastReceiver wifiReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        List<ScanResult> scanResults = wifiManager.getScanResults();
        unregisterReceiver(this);

        for (ScanResult result : scanResults) {
            //some code...
        }
    }
};

Now, by using ScanResults we can get features like ssid, bssid or capabilities etc. but I can't find a way to get ssid's frequency band. Is it possible?

Upvotes: 1

Views: 547

Answers (1)

Jack
Jack

Reputation: 5614

In ScanResult, the frequency field is how you can determine the band of the AP.

Specifically, the band would be 5GHz if frequency > 5000, and 2.4GHz if 3000 > frequency > 2000 (around 2400).

According to the 802.11 standard, it specifies that the 5GHz band's starting frequency is 5000MHz and 2.4GHz band's starting frequency is 2047MHz, the frequency you get from ScanResult#frequency will differ because of the different channels they are in.

The specific formula that converts the starting (base) frequency to the center (result) frequency is

freqCenter = freqStart + 5 * channelNumber

With that, you can derivate the channel number of the AP.

Upvotes: 4

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