predetermined period has expired the method determines that there are no protocol data units scheduled for transmission or re transmission and that the poll function was triggered by a u201c last pdu in retransmission buffer u201d trigger and selects a pdu to schedule for re transmission to fulfill the poll function application_number US 11034808 A description in order to overcome the prior art problems described above a preferred embodiment method of the present invention is described by example below assuming the configuration of the transmitting and the receiving stations is the same as that given in the prior art examples illustrated by fig5 and 6 above i e the transmitter is configured by upper layers to enable the following five poll triggers and also assuming that u2018 window based u2019 triggers and u2018 timer based u2019 triggers are disabled the poll prohibit function is configured with timer_poll_prohibit 250 ms one sdu is requested for transmission by an upper layer and an rlc transmission confirmation is requested by the upper layer when transmission of the sdu is positively acknowledged and that the sdu is segmented into four pdus having sequential sns 0 1 2 and 3 as in the prior art example in the example illustrated by fig7 the receiving station 72 successfully receives all four pdus 700.