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 User Equipment (UE) of a wireless network system, the method comprising:
initiating, by the UE, a procedure to deliver a transmission to a base station via a logical control channel of a wireless channel, the logical control channel being implemented on one of different logical control channels including a Common Control Channel (CCCH) and a Dedicated Control Channel (DCCH);
selecting, by the UE, a channel access priority class (CAPC) from a plurality of CAPCs of different channel access priorities, the selected CAPC having a channel access priority higher than a channel access priority of another CAPC included in the plurality of CAPCs, and the selecting based on a logical channel identity of the logical control channel of the wireless channel; and
performing, by the UE, a Listen-Before-Talk (LBT) procedure in accordance with the selected CAPC corresponding to the transmission.
2. The method of claim 1 , wherein the selecting of the CAPC based on the logical control channel identity of the logical control channel includes selecting the CAPC by utilizing a mapping indicating respective associations between the different logical control channels and respective CAPCs of the plurality of CAPCs, the different logical control channels having different logical channel identities.
3. The method of claim 1 , wherein the different logical control channels correspond to different sets of types of Signaling Radio Bearers (SRBs).
4. 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.
5. The method of claim 4 , 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.
6. The method of claim 5 , 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 signal radio bearer associated with the CP message.
7. The method of claim 4 , wherein a default CAPC of the control information has a higher channel access priority than a CAPC having a lowest channel access priority.
8. The method of claim 5 , 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.
9. The method of claim 4 , wherein the transmission includes a Radio Resource Control (RRC) message.
10. The method of claim 4 , wherein the transmission includes a (Medium Access Control (MAC) signaling data unit (SDU).
11. A user equipment (UE) comprising processing hardware and configured to implement the method according to claim 1 .
12. 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 UE, a second procedure to deliver a second transmission via the wireless channel;
selecting, by the UE, a second CAPC from the plurality of CAPCs, the second CAPC having a channel access priority higher than a respective channel access priority of at least one other CAPC included in the plurality of CAPCs; and
performing, by the UE, a second LBT procedure in accordance with the second CAPC.
13. The method of claim 1 , wherein:
the selecting of the CAPC from a plurality of CAPCs of different channel access priorities includes selecting a default CAPC of control information included in a payload of the transmission;
the selecting of the default CAPC of the control information includes utilizing a mapping indicating respective associations between multiple different types of control plane information and respective CAPCs of the plurality of CAPCs; and
the selecting of the default CAPC is based on an association between the selected default CAPC and a type of the control information.