Methods for wideband unlicensed channel access
Systems, methods, and devices for addressing wideband unlicensed channel access are disclosed herein. A device may be configured for different types of listen-before-talk (LBT) procedures, where the LBT type may refer to the frequency granularity of the LBT. There may be a hierarchical LBT procedure, where the LBT granularity changes at each point in the LBT procedure. There may be a selection of parameters for each LBT type. Some of the parameters may be shared over different points of the LBT procedure. There may be LBT subband sets for a subband set LBT type. There may be one or more indications of acquired LBT subbands on a condition of shared channel occupancy time. At one point in the LBT procedure, there may be a selection of a LBT subband or one or more subbands sets for transmission based on one or more criteria.
1 . A method of acquiring available resources, the method comprising:
performing a first listen before talk (LBT) procedure, wherein the first LBT is performed on an entire bandwidth part (BWP);
on a condition that the first LBT procedure is successful and the entire BWP is acquired, transmitting on the acquired BWP;
on a condition that the first LBT procedure is not successful and the entire BWP is not acquired, performing a second LBT procedure on one or more subband sets which include less subband sets than the entire BWP;
on a condition the second LBT procedure is successful and the one or more subband sets are acquired, transmitting on the one or more subband sets;
on a condition that the second LBT procedure is not successful and the one or more subband sets are not acquired, performing a third LBT procedure on one or more subbands, which include less subbands than the one or more subbands sets; and
on a condition that the third LBT procedure is successful and the one or more subbands are acquired,
and
transmitting, on the one or more subbands, during a shared channel occupancy time, an indication of the one or more acquired subbands.
2 . The method of claim 1 , wherein the one or more subband sets are determined by at least one of previous LBT operation, network configuration, measurements, and transmission type.
3 . The method of claim 1 , wherein the performing a second LBT procedure on one or more subband sets includes adjusting at least one LBT parameter.
4 . The method of claim 3 , wherein the at least one LBT parameter is a number of idle clear channel assessment (CCA) slots required.
5 . The method of claim 1 , further comprising monitoring multiple LBT subbands for a discovery reference signal (DRS) and transmitting a physical random access channel (PRACH) on an acquired LBT subband.
6 . The method of claim 1 , wherein a stopping criterion for the performing the second LBT procedure on the one or more subband sets is acquiring a sufficient number of subband sets or acquiring a largest possible contiguous group of subband sets.
7 . The method of claim 1 , wherein a stopping criterion for the performing the third LBT on the one or more subbands is acquiring a sufficient number of subbands.
8 . The method of claim 1 , wherein the performing the first LBT procedure on the entire BWP is category 4 LBT.
9 . The method of claim 8 , wherein the performing the second LBT procedure on the one or more subband sets and the performing the third LBT procedure with respect to one or more all subbands is category 4 LBT.
10 . The method of claim 8 , wherein the performing the second LBT procedure on the one or more subband sets and the performing the third LBT procedure with respect to one or more all subbands is category 2 LBT.
11 . A wireless transmit receive unit (WTRU) comprising:
a memory;
a transceiver; and
a processor, wherein the processor and the transceiver are configured to:
perform a first LBT procedure with respect to available resources on an entire bandwidth part (BWP),
on a condition that the first LBT procedure is not successful and the entire BWP is not acquired, perform a second LBT procedure on one or more subband sets, which include less subband sets than the entire BWP,
on a condition that the second LBT procedure is not successful and the one or more subband sets are not acquired, perform a third LBT procedure on one or more subbands, which include less subbands than the one or more subband sets, and
on a condition that the third LBT procedure is successful and the one or more subbands are acquired, and
transmit, on the one or more subbands, during a shared channel occupancy time, an indication of the one or more acquired subbands.
12 . The WTRU of claim 11 , wherein the WTRU is further configured with a stopping criterion for the performing the first LBT procedure with respect to the entire BWP, the stopping criterion being acquiring the entire BWP in an allocated time.
13 . The WTRU of claim 11 , wherein the WTRU is further configured with a stopping criterion for the performing the second LBT procedure with respect to the one or more subband sets, the stopping criterion being acquiring a sufficient number of subband sets or acquiring a largest possible contiguous group of subband sets.
14 . The WTRU of claim 11 , wherein the WTRU is further configured with a stopping criterion for the performing the third LBT procedure with respect to the one or more subbands, the stopping criterion being acquiring a sufficient number of subbands.
15 . The WTRU of claim 11 , wherein the subbands are at least 20 MHz.