Question: What is a prerequisite for a User Equipment (UE) to support a 15-bit length of PDCP Sequence Number in an E-UTRA network?
Option 1: The UE must support Split Bearers or 18-bit length of PDCP Sequence Number.
Option 2: The UE only needs to operate on a specific frequency band (e.g., FR1).
Option 3: The UE has to be capable of dual-connectivity (e.g., 4G and 5G simultaneously).
Option 4: The UE must have an activated IMS (IP Multimedia Subsystem) service.
Explanation: Supporting a 15-bit length of PDCP Sequence Number is contingent upon the UE's capability to handle more complex bearer configurations, such as Split Bearers, or its support for an even larger sequence number space (18 bits). This ensures that the UE can efficiently manage and differentiate between various data streams, especially in scenarios requiring enhanced throughput or low latency.