How RLC handles the status polling?

Question

For E.g

RLC polled the status PDU to receiver (polled till seq No . 16 ) and transmits the other sequence PDU (Seq No 17 ..).

But receiver didnt respond the polling PDU , Now transmitter wants to transmit polling PDU again. In this case will transmitter include Polling of Sequence no.16 or the latest sequence number sent after last polling.

Answer 1

I just saw this and thought my 3g RLC knowledge may give some hint..Not looked into LTE or 5g

If you see the 25.322 , it says that the

When "Poll" is configured, the Poll_SN field shall be set to VT(S)-1.

where
VT(S) - Send state variable.
This state variable contains the "Sequence Number" of the next AMD PDU to be transmitted for the first time (i.e. excluding retransmitted PDUs). It shall be updated after the aforementioned AMD PDU is transmitted or after transmission of a MRW SUFI which includes SN_MRWLENGTH >VT(S) (see subclause 11.6).

so I guess, POLL SN should always check the current next SN to be transmitted.

Just check, whether it is same for LTE and 5G..I guess the principle should be the same

Comments

Just checked the 5g RLC (38.322 v15.3.0)spec:

Upon expiry of t-PollRetransmit, the transmitting side of an AM RLC entity shall:
-    include a poll in an AMD PDU as described in section 5.3.3.2.

And section 5.3.3.2 says :
After submitting an AMD PDU including a poll to lower layer, the transmitting side of an AM RLC entity shall:
-    set POLL_SN to the highest SN of the AMD PDU among the AMD PDUs submitted to lower layer;

So it looks like the concept remains same as 3g