Channel access with a new radio unlicensed serving cell
A radio device may receive network assistance information relating to uplink channel access procedures, such as channel access types and related listen-before-talk techniques, via layer one signaling or higher layer signaling. For example, information may be provided via DCI, MAC CE, or RRC messaging, e.g,, received in a CORESET preceding the configured PRACH resources. Access procedures may be random access procedures, and may include indication via R.AR messaging. Access procedures may be triggered by a radio access point message, such as a PDCCH order or a handover request.
1. An apparatus, comprising a processor, a memory, and communication circuitry, the apparatus being connected to a network via the communication circuitry, the apparatus further comprising computer-executable instructions stored in the memory of the apparatus which, when executed by the processor of the apparatus, cause the apparatus to perform operations comprising:
perform a first type of uplink (UL) channel access procedure for a Random Access Channel (RACH) procedure;
send a first UL transmission for the RACH procedure;
receive a random access response (RAR) comprising network assistance information including channel access information;
determine, based on the channel access information, a second type of UL channel access procedure for the RACH procedure;
perform the second type of UL channel access procedure; and
send a second UL transmission for the RACH procedure.
2. The apparatus of claim 1 , wherein: the second type of uplink UL channel access procedure includes a listen-before-talk (LBT) procedure.
3. The apparatus of claim 2 , wherein the channel access information indicates the LBT procedure with random backoff.
4. The apparatus of claim 1 , wherein the channel access information indicates use of a default configuration.
5. The apparatus of claim 2 , wherein the channel access information indicates the LBT procedure without random backoff.
6. The apparatus of claim 1 , wherein the channel access information indicates the apparatus may perform the second UL transmission without performing a LBT procedure.
7. The apparatus of claim 1 , wherein the channel access information indicates use of an alternate configuration.
8. The apparatus of claim 1 , wherein the second type of UL channel access procedure is one of a set of more than two defined channel access types.
9. A method for uplink channel access comprising:
performing a first type of uplink (UL) channel access procedure for a Random Access Channel (RACH procedure;
sending a first UL transmission for the RACH procedure;
receiving a random access response (RAR) comprising network assistance information including channel access information;
determining, based on the channel access information, a second type of UL channel access procedure for the RACH procedure;
performing the second type of UL channel access procedure; and
sending a second UL transmission for the RACH procedure.
10. The method of claim 9 , wherein the second type of uplink UL channel access procedure includes a listen-before-talk (LBT) procedure.
11. The method of claim 10 , wherein the channel access information indicates the LBT procedure with random backoff.
12. The method of claim 10 , wherein the channel access information indicates the LBT procedure without random backoff.
13. The method of claim 9 , wherein the channel access information indicates use of a default configuration.
14. The method of claim 9 , wherein the channel access information indicates use of an alternate configuration.
15. The method of claim 9 , wherein the channel access information indicates performance of the second UL transmission without performing LBT.
16. The method of claim 9 , wherein the second type of UL channel access procedure is one of a set of more than two defined channel access types.