SMS manager does not send sms

i am a new Android developer. I written following code to send sms.
private void sendSMS(String phoneNumber)
{
String SENT = "SMS_SENT";
String DELIVERED = "SMS_DELIVERED";
final AlertDialog dialog = new AlertDialog.Builder(this).create();

PendingIntent sentPI = PendingIntent.getBroadcast(this, 0,
new Intent(SENT), 0);

PendingIntent deliveredPI = PendingIntent.getBroadcast(this, 0,
new Intent(DELIVERED), 0);

//---when the SMS has been sent---
registerReceiver(new BroadcastReceiver(){
@Override
public void onReceive(Context arg0, Intent arg1) {
switch (getResultCode())
{
case Activity.RESULT_OK:
dialog.setMessage("SMS is Successfully Sent for Contact Request ");
dialog.setTitle("ALERT:SMS Sent");

dialog.setButton(DialogInterface.BUTTON_POSITIVE, "OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
return;

}
});
dialog.show();
break;



case SmsManager.RESULT_ERROR_GENERIC_FAILURE:
Toast.makeText(getBaseContext(), "Generic failure",
Toast.LENGTH_SHORT).show();
break;
case SmsManager.RESULT_ERROR_NO_SERVICE:
Toast.makeText(getBaseContext(), "No service",
Toast.LENGTH_SHORT).show();
break;
case SmsManager.RESULT_ERROR_NULL_PDU:
Toast.makeText(getBaseContext(), "Null PDU",
Toast.LENGTH_SHORT).show();
break;
case SmsManager.RESULT_ERROR_RADIO_OFF:
Toast.makeText(getBaseContext(), "Radio off",
Toast.LENGTH_SHORT).show();
break;
}
return;
}
}, new IntentFilter(SENT));


registerReceiver(new BroadcastReceiver(){
@Override
public void onReceive(Context arg0, Intent arg1) {
switch (getResultCode())
{
case Activity.RESULT_OK:
Toast.makeText(getBaseContext(), "SMS delivered",
Toast.LENGTH_SHORT).show();
break;
case Activity.RESULT_CANCELED:
Toast.makeText(getBaseContext(), "SMS not delivered",
Toast.LENGTH_SHORT).show();
break;
}
}
}, new IntentFilter(DELIVERED));

SmsManager sms = SmsManager.getDefault();
sms.sendTextMessage(phoneNumber, null, messageToSend, sentPI, deliveredPI);
}

The code is running successsfully in Emulator but not in phone. It show the following error
case SmsManager.RESULT_ERROR_NO_SERVICE:
Toast.makeText(getBaseContext(), "No service",);

I have given the required permissions and have SIM(with enough balance) in the phone as well.

I am just stucked pls help.

thanks, perhaps I posted at wrong place.