Question: What is a mandatory feature for Mobile Integrated Access Backhaul (mobile IAB-MT) in addition to the standard IAB-MT capabilities, related to cell access control?
Option 1: Acquisition of gNB-ID-Length from System Information Block 1 (SIB1)
Option 2: Dynamic adjustment of transmit power based on backhaul load
Option 3: Support for additional frequency bands for backhaul links only
Option 4: Enhanced security authentication for IAB-MT nodes
Explanation: In the context of mobile IAB-MT, to ensure proper network operation and access control, acquiring the gNB-ID-Length from SIB1 is crucial. This information, obtained from System Information Block 1, helps in identifying the serving cell's unique ID length, which is vital for cell selection and barring decisions, especially when considering the specific needs of mobile IAB-MT deployments. This feature is directly related to how a mobile IAB-MT UE interacts with the network at a fundamental level, impacting its ability to access barred cells based on the mobileIAB-Support indicator.