Question: What constitutes 'RLC data volume' for MAC buffer status reporting in a User Equipment (UE) using Radio Link Control (RLC) protocol, specifically in the context of 5G New Radio (NR)?
Option 1: Only RLC SDUs and segments not yet included in an RLC data PDU.
Option 2: A combination of RLC SDUs/segments not in an RLC PDU, RLC data PDUs pending initial transmission, and those pending retransmission (RLC AM), plus the estimated size of a forthcoming STATUS PDU if its transmission is not prohibited.
Option 3: All transmitted RLC data PDUs plus any RLC SDUs/segments in the process of being segmented.
Option 4: Only delay-critical RLC SDUs, segments, and related pending PDUs.
Explanation: For accurate MAC buffer status reporting, the UE must consider a comprehensive set of data volumes. This includes not just the raw, untransmitted data (RLC SDUs/segments), but also data that is queued for initial send or re-send due to errors (RLC data PDUs pending transmission or retransmission under RLC AM). Additionally, if a STATUS PDU is impending and not temporarily blocked, its estimated size also contributes to this volume, ensuring buffer reporting reflects all upcoming transmissions. This holistic approach ensures efficient network resource allocation and management.