Question: In a 3GPP-compliant USIM-enabled device, what is a prerequisite for the Mobile Equipment (ME) to initiate WLAN PLMN Selection procedures as outlined in WLAN interworking protocols?
Option 1: The ME must have an active cellular connection.
Option 2: The User Controlled PLMN selector and/or Operator Controlled PLMN selector files (EFUPLMNWLAN and EFOPLMNWLAN) must be empty.
Option 3: The device's WLAN adapter must support a specific set of frequencies.
Option 4: Service numbers 60 or 61 ("available") must be present.
Explanation: For the ME to engage in WLAN PLMN Selection procedures, as described in the context of 3GPP system to Wireless Local Area Network (WLAN) interworking, a specific service requirement must be met. This involves having either service number 60 or 61 marked as "available". This prerequisite ensures that the device is configured to handle the selection process for WLAN networks based on PLMN (Public Land Mobile Network) settings, which are crucial for seamless integration and authentication with wireless networks. The presence of these services indicates the device’s capability to manage user-controlled and/or operator-controlled PLMN selections for WLAN connections.