Question: For an LTE User Equipment (UE) that is IMS voice capable, what is the requirement regarding Service Specific Access Control (SSAC) support in relation to access barring parameters?
Option 1: Optional support for SSAC, with flexibility in applying common and per PLMN access barring parameters.
Option 2: Mandatory support for SSAC, but only considering common access barring parameters across all PLMNs.
Option 3: Conditional support for SSAC, mandated only when specific IMS services are activated on the UE.
Option 4: Mandatory support for SSAC, subject to both common and per Public Land Mobile Network (PLMN) access barring parameters.
Explanation: This is because the requirement specifically states that for UEs capable of IMS voice in LTE, supporting Service Specific Access Control is mandatory. Moreover, this support must consider not just common access barring parameters but also those specific to each Public Land Mobile Network (PLMN), ensuring a more tailored and secure access control mechanism based on both general and network-specific rules.