Android Geofence Implementation get Alart through Cell-ID( NetWork Provider)

Question

I am using Geofence code from http://developer.android.com/training/location/geofencing.html

It is working fine If I am enabling GPS and uses following code to request GPS

locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000*60 , 0, new MyLocationListener());

What should I do to get Geofence alart from Cell-Id

when I use

locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000*60 , 0, new MyLocationListener());

It shows entered in Geofence but the actual location i am getting is not in fence.

I have set geofence radius 100m.

Do we need net activated to make this program working ?

Do we need any login in google play ?

What am I missing ?