Method and device for transmitting and receiving signals in wireless communication system
摘要
說(shuō)明書
For DL signal transmission (e.g., transmission of a DL signal such as a PDSCH/PDCCH/enhanced PDCCH (EPDCCH)), the BS may initiate a CAP (S1210). The BS may randomly select a backoff counter N within a contention window (CW) according to step 1. N is set to an initial value Ninit (S1220). Ninit is a random value selected from the values between 0 and CWp. Subsequently, when the backoff counter value N is 0 according to step 4 (S1230; Y), the BS terminates the CAP (S1232). The BS may then perform a Tx burst transmission including transmission of a PDSCH/PDCCH/EPDCCH (S1234). On the contrary, when the backoff counter value N is not 0 (S1230; N), the BS decrements the backoff counter value by 1 according to step 2 (S1240). Subsequently, the BS checks whether the channel of U-cell(s) is idle (S1250). If the channel is idle (S1250; Y), the BS determines whether the backoff counter value is 0 (S1230). On the contrary, when the channel is not idle, that is, the channel is busy (S1250; N), the BS determines whether the channel is idle during a longer defer duration Td (25 usec or longer) than a slot duration (e.g., 9 usec) according to step 5 (S1260). If the channel is idle during the defer duration (S1270; Y), the BS may resume the CAP. The defer duration may include a 16-usec duration and the immediately following mp consecutive slot durations (e.g., each being 9 usec). On the contrary, if the channel is busy during the defer duration (S1270; N), the BS re-checks whether the channel of the U-cell(s) is idle during a new defer duration by performing step S1260 again.
Table 3 illustrates that mp, a minimum CW, a maximum CW, a maximum channel occupancy time (MCOT), and an allowed CW size applied to a CAP vary according to channel access priority classes.
