37.213协议 nr-u Type 1 DL channel access问题请教

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If an eNB/gNB has not transmitted a transmission after step 4 in the procedure above, the eNB/gNB may transmit a transmission on the channel, if the channel is sensed to be idle at least in a sensing slot duration Tsl when the eNB/gNB is ready to transmit and if the channel has been sensed to be idle during all the sensing slot durations of a defer duration Td immediately before this transmission.这段协议看得非常费解，当执行完上面的step4后，设备并不能马上发数据，还需要一段准备时间；当设备准备就绪后，是还需要检测一个感知时隙再发吗？还是说在准备过程中就在检测，当准备就绪后也检测完了立即可发？多谢