Enhanced listen-before-talk
An enhanced LBT procedure ( 200 ) mitigates unnecessary delays in delivering transmissions between User Equipment and base stations over unlicensed spectrum. A UE or base station selects a particular CAPC corresponding to an intended transmission ( 225 ) based on an intelligent mapping of different types of transmission payload (e.g., transmission payload other than or in in addition to pre-defined, QoS-related UP message data payload) to different CAPCs. Most (if not all) of the mapped CAPCs corresponding to the different types of transmission payload are of a higher priority than a lowest priority CAPC ( 212 - 222 ), resulting in channel access procedures that are more commensurate with respective transmission payloads. The intelligent mapping may indicate different priorities among different types of transmission payload and/or different types of messages, and/or may indicate which type of transmission is to govern selection of a CAPC when multiple types of transmission payload are included in a single, intended transmission.
1. A method in a base station of a wireless network system, the method comprising:
initiating, by the base station, a procedure to deliver a transmission to a User Equipment (UE) via a logical control channel of a wireless channel;
selecting, by the base station, a channel access priority class (CAPC) from a plurality of CAPCs of different channel access priorities, the selected CAPC associated with the logical control channel of the wireless channel, and the logical control channel having a channel access priority higher than a channel access priority of another CAPC that is included in the plurality of CAPCs and that is not associated with any logical control channel of the wireless channel; and
performing, by the base station, a Listen-Before-Talk (LBT) procedure in accordance with the selected CAPC corresponding to the transmission.
2. The method of claim 1 , wherein selecting the CAPC associated with the logical control channel includes selecting the CAPC by utilizing a mapping indicating respective associations between different logical channels and respective CAPCs of the plurality of CAPCs.
3. The method of claim 2 , wherein the logical control channel is implemented on one of different logical channels including a Common Control Channel (CCCH) and a Dedicated Control Channel (DCCH).
4. The method of claim 2 , wherein the different logical channels correspond to different sets of types of Signaling Radio Bearers (SRBs).
5. The method of claim 2 , wherein a payload of the transmission includes control information to be delivered via the logical control channel; and the mapping indicates an association between the selected CAPC and the control information.
6. The method of claim 5 , wherein:
the payload of the transmission includes a control plane (CP) message; and
the mapping indicates an association between the selected CAPC and the CP message.
7. The method of claim 6 , wherein:
the CP message has an association with a type of signal radio bearer (SRB); and
the mapping indicates the association between the selected CAPC and the type of SRB associated with the CP message.
8. The method of claim 5 , wherein a default CAPC of the control information has a higher channel access priority than a CAPC having a lowest channel access priority.
9. The method of claim 6 , wherein:
the CP message has an association with a first type of signal radio bearer (SRB);
the selected CAPC is a first CAPC associated with the first type of SRB and that has a channel access priority level higher than a channel access priority of a second CAPC associated with a second type of SRB;
the mapping indicates the association between the first CAPC and the first type of SRB; and
the mapping indicates the association between the second CAPC and the second type of SRB.
10. The method of claim 5 , wherein the transmission includes a Radio Resource Control (RRC) message.
11. The method of claim 5 , wherein the transmission includes a (Medium Access Control (MAC) signaling data unit (SDU).
12. A base station comprising processing hardware and configured to implement the method according to claim 1 .
13. The method of claim 1 , wherein the procedure is a first procedure, the transmission is a first transmission, the selected CAPC is a first selected CAPC, the LBT procedure is a first LBT procedure, and the method further comprises:
initiating, by the base station, a second procedure to deliver a second transmission via the wireless channel;
selecting, by the base station, a second CAPC from the plurality of CAPCs, the second CAPC having a channel access priority higher than a respective channel access priority of the at least one other CAPC included in the plurality of CAPCs; and
performing, by the base station, a second LBT procedure in accordance with the second CAPC.