A method and system are described for providing a wireless telecommunications service provider with location information of a mobile service subscriber. When a mobile subscriber device acknowledges receipt of a data packet received at the mobile device, or when the mobile device originates a transmission, the cellular telecommunications site, or base station, receiving the acknowledgement or transmission serves as an entry node into the telecommunications system. Resource identification information for the entry node is extracted from billing message traffic logs and is exposed to the service provider. The service provider uses the resource identification information to find the location of the entry node in an entry node information database. Alternatively the location may be provided with the resource identification information. Provision of location information allows the service provider to know that its mobile subscriber is located in the area covered by that particular entry node.