Channel occupancy time indication for NR based unlicensed operation
Devices and methods of providing channel occupancy time (COT) are described. After a gNB acquires an unlicensed channel for a COT, the gNB indicates the COT length to a UE using a PDCCH having a DCI formed in accordance with DCI format 2_0. The slot format of the last slot of the COT is indicated using a reserved slot format indicator that is reserved to indicate the end of the COT. The reserved slot format indicator indicates a last slot format of available slot formats of DCI format 2_0. Dummy bits fill the DCI after the reserved slot format indicator. Alternatively, to indicate the COT length, a COT field dedicated to providing the COT is used in the DCI or the CRC is masked using a slot format indication Radio Network Temporary Identifier.
1. An apparatus comprising:
processing circuitry configured to cause a user equipment (UE) to:
decode downlink control information (DCI) from a base station;
determine, from a channel occupancy time (COT) field of the downlink control information, COT information of a COT acquired by the base station, wherein the COT information indicates a remaining duration of the COT, wherein the COT field is different from a slot format indication (SFI) field of the DCI;
determine, according to radio resource control (RRC) signaling, a presence of the COT field in the DCI, and a length of the COT field in the DCI; and
communicate data with the base station based on the COT information.
2. The apparatus of claim 1 , wherein the DCI is decoded from a physical downlink control channel (PDCCH), wherein the DCI has been formed in accordance with a DCI format, wherein the processing circuitry is further configured to cause the UE to:
determine the COT information from the COT field using the DCI format.
3. The apparatus of claim 2 , wherein a cyclic redundancy check (CRC) of the DCI is masked with either COT-Radio Network Temporary Identifier (RNTI) or a slot format indication RNTI, depending on whether or not the DCI format contains the COT field.
4. The apparatus of claim 2 , wherein the processing circuitry is further configured to cause the UE to decode higher layer signaling that indicates:
a size of the DCI according to the DCI format,
a number of available slot formats supported by the DCI according to the DCI format, and
a monitoring period of the DCI according to the DCI format.
5. The apparatus of claim 1 , wherein the DCI is format 2_0.
6. The apparatus of claim 1 , wherein the DCI has a maximum size of 128 bits.
7. The apparatus of claim 1 , wherein the DCI includes an indication of one or more frequency sub-bands associated with the remaining duration of the COT.
8. The apparatus of claim 1 , further comprising:
a transceiver coupled to the processing circuitry; and
a memory configured to store the COT information.
9. The apparatus of claim 1 , wherein the remaining duration of the COT indicates a time between reception of the DCI and an end of the COT.
10. The apparatus of claim 1 , wherein the processing circuitry is further configured to cause the UE to:
determine that the COT information is indicated by the DCI based on a result of masking a cyclic redundancy check (CRC) of the DCI with a Radio Network Temporary Identifier (RNTI).
11. The apparatus of claim 1 , wherein the base station is a gNodeB of 3GPP 5G New Radio.
12. The apparatus of claim 1 , wherein the channel occupancy time (COT) is associated with a channel on an unlicensed band.
13. A user equipment (UE) comprising:
a radio transceiver; and
processing circuity coupled to the radio transceiver, and configured to:
decode downlink control information (DCI) from a base station;
determine, from a channel occupancy time (COT) field of the downlink control information, COT information of a COT acquired by the base station, wherein the COT information indicates a remaining duration of the COT, wherein the COT field is different from a slot format indication (SFI) field of the DCI;
determine, according to radio resource control (RRC) signaling, a presence of the COT field in the DCI, and a length of the COT field in the DCI; and
communicate data with the base station based on the COT information.
14. An apparatus comprising:
processing circuitry configured to cause a base station to:
engage in a Listen-Before-Talk (LBT) procedure for communication with a user equipment (UE) on an unlicensed band;
acquire a channel in the unlicensed band for a channel occupancy time (COT) based on a successful outcome of the LBT procedure;
encode, for transmission to the UE, a physical downlink control channel (PDCCH) having downlink control information (DCI), wherein the DCI includes a COT field and a slot format indication different from the COT field, wherein the COT field includes COT information indicating a remaining duration of the COT; and
encode, in radio resource control (RRC) signaling, an indication of a presence of the COT field in the DCI and a length of the COT field in the DCI.
15. The apparatus of claim 14 , wherein the DCI has been formatted according to a DCI format 2.0.
16. The apparatus of claim 14 , wherein the DCI has a maximum length of 128 bits.
17. The apparatus of claim 14 , wherein the DCI includes an indication of one or more frequency sub-bands associated with the remaining duration of the COT.