Frame based equipment (FBE) in NR-U
Methods and apparatuses are described herein for transmission priority, collisions, and sharing in the COT by frame based equipment (FBE). In accordance with one embodiment, a wireless communications device such as an FBE, may conduct two stage channel sensing to avoid collision between other FBEs nodes. The wireless communications device may adjust the energy threshold to reflect a channel access priority. The FBE may conducting continuous and non-continuous second stage channel sensing. The FBE may perform enhanced two stage channel sensing to exploit the remaining portion of the COT. The FBE may store a configuration for the second stage of channel sensing for both the downlink (DL) and uplink (UL).
1 . A wireless transmit/receive unit (WTRU), the WTRU comprising a processor and a memory, the WTRU further including computer-executable instructions stored in the memory of the WTRU which, when executed by the processor of the WTRU, cause the WTRU to:
receive configuration information, wherein the configuration information indicates that the WTRU operates as frame-based equipment (FBE);
determine a priority associated with an intended transmission;
determine, based on the priority, an energy detection threshold;
perform, during a portion of a first fixed frame period (FFP), a first clear channel assessment (CCA), wherein the first FFP comprises a first channel occupancy time (COT);
indicate a clear channel during the portion of the first FFP based on a use of the energy detection threshold;
transmit data associated with the intended transmission;
perform a second CCA during a portion of a second FFP, wherein the second FFP comprises a second COT, wherein the duration of performing the second CCA is shorter than the duration of performing the first CCA, and wherein the WTRU operates as a load based equipment (LBE) during the second COT of the second FFP; and
when a channel is occupied for a predetermined consecutive number of FFPs, release the channel and do not occupy the channel again for the predetermined consecutive number of FFPs.
2 . The WTRU of claim 1 , wherein the computer-executable instructions, when executed by the processor of the WTRU, further cause the WTRU to:
based on the clear channel, and when the first or second COT is initiated by the WTRU, transmit a channel acquisition indicator (CAI).
3 . The WTRU of claim 2 , wherein the CAI indicates at least one of:
one or more parameters associated with a frame periodicity, the priority, a duration associated with the transmitted data, spatial information, operation bandwidth, a time offset between an FFP of a base station and the first FFP of the WTRU, or an indication of first or second COT sharing.
4 . The WTRU of claim 2 , wherein the CAI is transmitted via:
a Physical Random Access Channel (PRACH), wherein the data associated with the intended transmission is transmitted after the PRACH,
piggybacked uplink control information (UCI) on a Physical Uplink Shared Channel (PUSCH), or
a Physical Uplink Control Channel (PUCCH).
5 . The WTRU of claim 1 , wherein the computer-executable instructions, when executed by the processor of the WTRU, further cause the WTRU to:
based on the clear channel, and when the first or second COT is initiated by a base station, receive a channel acquisition indicator (CAI).
6 . The WTRU of claim 5 , wherein the CAI indicates at least one of:
one or more parameters associated with a frame periodicity, the priority, a duration associated with the transmitted data, spatial information, operation bandwidth, a time offset between an FFP of a base station and the first FFP of the WTRU, or an indication of first or second COT sharing.
7 . The WTRU of claim 5 , wherein the CAI is received via radio resource control (RRC) signaling broadcast to multiple WTRUs, or dedicated RRC signaling for the WTRU.
8 . The WTRU of claim 1 , wherein the determining, based on the priority, the energy detection threshold comprises:
determining, based on an energy offset associated with the priority, an energy threshold.
9 . The WTRU of claim 1 , wherein a portion of the first or second COT varies in size based on the priority.
10 . The WTRU of claim 1 , wherein the computer-executable instructions, when executed by the processor of the WTRU, further cause the WTRU to:
apply a time offset between an FFP of a base station and the first FFP of the WTRU, relative to a beginning of the FFP of the base station.
11 . A method for use in a wireless transmit/receive unit (WTRU), the method comprising:
receiving configuration information, wherein the configuration information indicates that the WTRU operates as frame-based equipment (FBE);
determining a priority associated with an intended transmission;
determining, based on the priority, an energy detection threshold;
performing, during a portion of a first fixed frame period (FFP), a first clear channel assessment (CCA), wherein the first FFP comprises a first channel occupancy time (COT);
indicating a clear channel during the portion of the first FFP based on a use of the energy detection threshold;
transmitting data associated with the intended transmission;
performing a second CCA during a portion of a second FFP, wherein the second FFP comprises a second COT, wherein the duration of performing the second CCA is shorter than the duration of performing the first CCA, and wherein the WTRU operates as a load based equipment (LBE) during the second COT of the second FFP; and
when a channel is occupied for a predetermined consecutive number of FFPs, releasing the channel and do not occupy the channel again for the predetermined consecutive number of FFPs.
12 . The method of claim 11 , further comprising:
based on the clear channel, and when the first or second COT is initiated by the WTRU, transmitting a channel acquisition indicator (CAI).
13 . The method of claim 12 , wherein the CAI indicates at least one of:
one or more parameters associated with a frame periodicity, the priority, a duration associated with the transmitted data, spatial information, operation bandwidth, a time offset between an FFP of a base station and the first FFP of the WTRU, or an indication of first or second COT sharing.
14 . The method of claim 12 , wherein the CAI is transmitted via:
a Physical Random Access Channel (PRACH), wherein the data associated with the intended transmission is after the PRACH,
piggybacked uplink control information (UCI) on a Physical Uplink Shared Channel (PUSCH), or
a Physical Uplink Control Channel (PUCCH).
15 . The method of claim 11 , further comprising:
based on the clear channel, and when the first or second COT is initiated by a base station, receiving a channel acquisition indicator (CAI).
16 . The method of claim 15 , wherein the CAI indicates at least one of:
one or more parameters associated with a frame periodicity, the priority, a duration associated with the transmitted data, spatial information, operation bandwidth, a time offset between an FFP of a base station and the first FFP of the WTRU, or an indication of first or second COT sharing.
17 . The method of claim 15 , wherein the CAI is received via:
radio resource control (RRC) signaling broadcast to multiple WTRUs, or
dedicated RRC signaling for the WTRU.