Question: Under what condition(s), apart from reaching pollPDU or pollByte thresholds, will the transmitting side of an AM RLC entity include a poll in the RLC data PDU?
Option 1: When the transmission buffer is full and no new RLC data PDU can be assembled.
Option 2: When both the transmission buffer and the retransmission buffer become empty (excluding awaiting acknowledgements) or when window stalling occurs.
Option 3: Upon receiving an acknowledgement for all previously sent RLC data PDUs from the receiving side.
Option 4: Immediately after the first RLC data PDU is transmitted to a newly established connection.
Explanation: Apart from the thresholds, a poll is included in the RLC data PDU when both transmission and retransmission buffers are empty (excluding PDUs awaiting acknowledgements) after transmission, or when no new RLC data PDU can be sent due to window stalling, ensuring efficient resource use and timely feedback without unnecessary polling.