Methods and apparatuses for performing random access procedures
A method performed by an apparatus of wireless communications is provided. The method includes receiving a plurality of Random Access (RA) configurations associated with a set of Bandwidth Parts (BWPs), selecting a first BWP from the set of BWPs to perform an RA procedure, and selecting a first Synchronization Signal Block (SSB) associated with the first BWP. The first SSB may be configured with a first RA resource. The method further includes transmitting a first RA preamble using the first RA resource and setting the first BWP as a first-activated BWP when the RA procedure is successfully performed.
1. An apparatus for wireless communications, comprising:
a memory; and
at least one processor coupled to the memory, the at least one processor being configured to:
receive a plurality of Random Access (RA) configurations associated with a set of Bandwidth Parts (BWPs);
select a first BWP from the set of BWPs to perform an RA procedure;
select a first Synchronization Signal Block (SSB) associated with the first BWP, the first SSB being configured with a first RA resource;
transmit a first RA preamble using the first RA resource; and
set the first BWP as a first-activated BWP when the RA procedure is successfully performed, wherein:
the first RA resource is contained in a dedicated Listen Before Talk (LBT) unit in the first BWP,
the dedicated LBT unit occupies a part of resources of the first BWP, and
the first RA preamble is transmitted when an LBT procedure performed on the dedicated LBT unit is successful.
2. The apparatus of claim 1 , wherein the at least one processor is further configured to:
perform a reselection procedure during the RA procedure, the reselection procedure including:
selecting a second BWP from the set of BWPs;
switching to the second BWP to continue the RA procedure;
selecting a second SSB associated with the second BWP, the second SSB being configured with a second RA resource; and
transmitting a second RA preamble using the second RA resource.
3. The apparatus of claim 2 , wherein the second SSB is selected when the second BWP has a lowest channel occupancy rate among the set of BWPs.
4. The apparatus of claim 2 , wherein the second SSB is selected when the second SSB has a strongest signal strength level compared to other SSBs.
5. The apparatus of claim 2 , wherein the second BWP is selected when the second BWP has a highest priority value among the set of BWPs.
6. The apparatus of claim 1 , wherein the first BWP is selected from the set of BWPs based on at least one of a channel occupancy condition and whether a contention-free RA resource is configured.
7. The apparatus of claim 1 , wherein each of the plurality of RA configurations is configured based on a per LBT unit basis.
8. The apparatus of claim 1 , wherein the at least one processor is further configured to:
transmit capability information to a base station to indicate whether the apparatus supports performing the RA procedure using more than one BWP in the set of BWPs.
9. The apparatus of claim 1 , wherein the at least one processor is further configured to:
transmit capability information to a base station to indicate whether the apparatus supports performing an LBT procedure on more than one LBT unit.
10. A method performed by an apparatus of wireless communications, the method comprising:
receiving a plurality of Random Access (RA) configurations associated with a set of Bandwidth Parts (BWPs);
selecting a first BWP from the set of BWPs to perform an RA procedure;
selecting a first Synchronization Signal Block (SSB) associated with the first BWP, the first SSB being configured with a first RA resource;
transmitting a first RA preamble using the first RA resource; and
setting the first BWP as a first-activated BWP when the RA procedure is successfully performed, wherein:
the first RA resource is contained in a dedicated Listen Before Talk (LBT) unit in the first BWP,
the dedicated LBT unit occupies a part of resources of the first BWP, and
the first RA preamble is transmitted when an LBT procedure performed on the dedicated LBT unit is successful.
11. The method of claim 10 , further comprising:
performing a reselection procedure during the RA procedure, the reselection procedure including:
selecting a second BWP from the set of BWPs;
switching to the second BWP to continue the RA procedure;
selecting a second SSB associated with the second BWP, the second SSB being configured with a second RA resource; and
transmitting a second RA preamble using the second RA resource.
12. The method of claim 11 , wherein the second SSB is selected when the second BWP has a lowest channel occupancy rate among the set of BWPs.
13. The method of claim 11 , wherein the second SSB is selected when the second SSB has a strongest signal strength level compared to other SSBs.
14. The method of claim 11 , wherein the second BWP is selected when the second BWP has a highest priority value among the set of BWPs.
15. The method of claim 10 , wherein the first BWP is selected from the set of BWPs based on at least one of a channel occupancy condition and whether a contention-free RA resource is configured.
16. The method of claim 10 , wherein each of the plurality of RA configurations is configured based on a per LBT unit basis.
17. The method of claim 10 , further comprising:
transmitting capability information to a base station to indicate whether the apparatus supports performing the RA procedure using more than one BWP in the set of BWPs.
18. The method of claim 10 , further comprising: transmitting capability information to a base station to indicate whether the apparatus supports performing an LBT procedure on more than one LBT unit.