With reference to the first aspect, in a possible implementation, the location service request delivered by the gateway mobile location network element includes action indication information, and the action indication information is used to indicate the location service operation. When receiving the action indication information, the access management network element verifies whether the action indication information matches the first location privacy setting data. If the action indication information matches the first location privacy setting data, the access management network element determines that the gateway mobile location network element does not tamper with the first location privacy setting data. If the action indication information does not match the first location privacy setting data, the access management network element determines that the gateway mobile location network element tampers with the first location privacy setting data. In this case, the access management network element may report an error reason that the gateway mobile location network element tampers with the first location privacy setting data.
With reference to the first aspect, in a possible implementation, the data transmission system further includes an access management network element and a gateway mobile location network element.
The gateway mobile location network element is configured to send a location privacy setting data obtaining request to the data management network element, where the location privacy setting data obtaining request includes a third freshness parameter, and the third freshness parameter includes a third counter value and a third function counter value.