Question: Which type of RLC PDU is specifically used for retransmitting a portion of previously sent data, requiring segmentation, in an Acknowledged Mode (AM) RLC entity?
Option 1: TMD (Transparent Mode Data) PDU
Option 2: UMD (Unacknowledged Mode Data) PDU
Option 3: AMD PDU segment
Option 4: Full AMD PDU without segmentation
Explanation: In the context of RLC protocol, an Acknowledged Mode (AM) RLC entity uses an AMD PDU segment to retransmit a portion of previously sent data that requires segmentation. This optimizes resource usage by only resending the needed part of an original AMD PDU, enhancing transmission efficiency in wireless communications.