The bar to pbtain caller tower info is quite high. In a legal process, such information can provided by network nodal officer only when issued a nodice under s/91 crpc. Eventually it depends on your need. If it is of utmost importance as per your requirement, you can register a court complaint and get the nodal officer to provide it. It is open to the opposite party to object strongly in case his information is being requested, as it falls under the domain of private information. In some instances the police are alo known to assist in obtaining this information, however invariably this may incur additional expenses the kind of which I will not make any public statements about.