Scanning for wifi signals only in 2.4Ghz band

Question

I need to scan for available Wi-Fi signals and their strengths. I\'m using wifiManager.startScan(); and asynchronous wifiManager.getScanResult();.

Answer 1

Supplicant config file provide option to explicitly declare range of channels where you want to scan for available network. If you device uses wpa_supplicant then in config file you can define scan frequency like below.

scan_freq: List of frequencies to scan

for more info look for above text in below mention link.

Visit http://hostap.epitest.fi/gitweb/gitweb.cgi?p=hostap.git;a=blob_plain;f=wpa_supplicant/wpa_supplicant.conf .

Answer 2

Is there any way I could tell the device to scan only in the 2.4GHz band

I think there is not way how to achieve it.

All you can do is only call startScan() and wait for results. Then you can filter results due to their frequency especially for 2.4Ghz frequency of each AP (Access Point) should be bellow 2500 Mhz.

Answer 3

NOTE: These api's are removed from Android Nogut version. Applicable till Mashmallow

/**
 * Auto settings in the driver. The driver could choose to operate on both
 * 2.4 GHz and 5 GHz or make a dynamic decision on selecting the band.
 * @hide
 */
public static final int WIFI_FREQUENCY_BAND_AUTO = 0;

/**
 * Operation on 5 GHz alone
 * @hide
 */
public static final int WIFI_FREQUENCY_BAND_5GHZ = 1;

/**
 * Operation on 2.4 GHz alone
 * @hide
 */
public static final int WIFI_FREQUENCY_BAND_2GHZ = 2;

Use above constants part of WifiManager.java, to set the required frequency bands. And we can set frequency with API setFrequencyBand(int mode, boolean persist). These are hidden API's.

code snippet:

WifiManager wm = (WifiManager)getSystemService(Context.WIFI_SERVICE);

// To scan only 2.4 GHz Frequency band

// true, if this needs to be remembered

wm.setFrequencyBand(2, false);

// Start scan.

wm.startScan();

// To get the frequency band used.

int band = wm.getFrequncyBand();

Answer 4

    final WifiManager wifiManager = (WifiManager)



context.getApplicationContext().getSystemService(Context.WIFI_SERVICE);                

wifiManager.getScanResults().get(0).frequency >= 2500