Android Wifi Roaming Through AP With Same SSID

I saw that Android system has a bad behavior with Wifi roaming. We have a Wifi centralized network with many AP with a signle SSID. The Adroid Phones wont roams seamlessly. An Andr

Solution 1:

You cannot do this as you describe. A client cannot determine the state of the TCP connection on it's own. Your network must also move the communication channel from one AP to another. This can be done with the right network controllers.

Also, you should look at IEEE 802.11k - https://en.wikipedia.org/wiki/IEEE_802.11k-2008

Solution 2:

Add below permissions;

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />

Register for below intent;

private WifiBroadcastReceiver wifiBroadcastReceiver = new WifiBroadcastReceiver();

Then in routine;

registerReceiver(wifiBroadcastReceiver, new IntentFilter("android.net.wifi.SCAN_RESULTS"));

Use the below class to change the reassociation;

public class WifiBroadcastReceiver extends BroadcastReceiver {

    private WiFiManager manager = null;//set the value in constructor
    private WifiConfiguration connectedConfiguration = null;//set the value in constructor
    private int connectedNetId;

    private void updateConnectedConfiguration(String ssid) {
        configs = manager.getConfiguredNetworks();
        int nid = 0;
        for (WifiConfiguration cnf : configs) {
            if (cnf.SSID.substring(1, cnf.SSID.length() - 1).equals(ssid)) {
                connectedConfiguration = cnf;
                connectedNetId = nid;
            }
            nid++;
        }
    }


    public void onReceive(Context c, Intent intent) {
        List<ScanResult> results = manager.getScanResults();
        WifiInfo info = manager.getConnectionInfo();
        ScanResult stronger = null;
        for (ScanResult scanResult : results) {
            try {
                if (scanResult.SSID.equals(info.getSSID())) {
                    if (stronger == null) {
                        if (WifiManager.compareSignalLevel(info.getRssi() + 5, scanResult.level) < 0) {
                            stronger = scanResult;
                        }
                    } else if (WifiManager.compareSignalLevel(stronger.level, scanResult.level) < 0) {
                        stronger = scanResult;
                    }
                }
            } catch (Exception e) {
            }
        }
        if (stronger != null && !stronger.BSSID.equals(info.getBSSID())) {
            updateConnectedConfiguration(info.getSSID());
            if (connectedConfiguration != null) {
                connectedConfiguration.BSSID = stronger.BSSID;
                manager.updateNetwork(connectedConfiguration);
                manager.saveConfiguration();
                manager.enableNetwork(connectedNetId, true);
                manager.reassociate();
                info = manager.getConnectionInfo();
                //showNotification("\nConnecting " + stronger.SSID, stronger.BSSID + " " + stronger.level + "dBm");
            }
        }
    }
}