Question: Upon expiry of t-PollRetransmit in an AM (Acknowledged Mode) RLC entity, what action is taken if both buffers are empty or no new RLC SDU can be transmitted?
Option 1: The RLC entity immediately releases all resources associated with the current transmission session.
Option 2: The transmitting side includes a poll in an AMD PDU for either the RLC SDU with the highest SN awaiting retransmission or any unacknowledged RLC SDU.
Option 3: The RLC entity switches to Transparent Mode (TM) to handle any further data transmission.
Option 4: The expiry of t-PollRetransmit is ignored if both buffers are empty, awaiting new RLC SDUs for transmission.
Explanation: Upon expiry of t-PollRetransmit, if the conditions of empty buffers (excluding pending acknowledgments) or inability to transmit new RLC SDUs are met, the AM RLC entity proactively manages retransmissions by polling for the most urgent unacknowledged or awaiting-retransmission RLC SDU. This ensures efficient use of resources and minimizes potential data loss in acknowledged mode transmissions within wireless communication networks like 5G NR (New Radio).