Operation of wireless communication devices in unlicensed spectrum for frame-based equipment (FBE) networks
Embodiments of systems and methods for operating wireless communication devices (e.g., User Equipments (UEs)) as initiating and responding devices in a Frame-Based Equipment (FBE) New Radio (NR) Unlicensed (NR-U) network are disclosed. The proposed methods allow operating the NR-U network as an FBE system in a flexible manner that supports a wide range of deployments not limited to the UE operating as a responding device. In some embodiments, methods to operate UEs as initiating and responding devices in a FBE-based NR-U network are disclosed.
1. A method performed by a wireless communication device, the method comprising:
receiving, from a network node, a channel access mode indication, the channel access mode indication being an indication of whether the wireless communication device is to operate in a Frame-Based Equipment (FBE) channel access mode or a Load-Based Equipment (LBE) channel access mode;
determining a channel access mode in which to operate based on the channel access mode indication, wherein the determined channel access mode is the FBE channel access mode, and operating in the determined channel access mode comprises operating as a responding node by:
determining whether a Downlink (DL) transmission is received during a particular Fixed Frame Period (FFP); and
upon determining that the DL transmission is received during the particular FFP, transmitting an Uplink (UL) transmission in the particular FFP; and
operating in the determined channel access mode.
2. The method of claim 1 wherein the channel access mode indication is broadcast by the network node.
3. The method of claim 2 further comprising receiving a dedicated signal from the network node indicating the channel access mode indication, wherein the channel access mode is determined based on the dedicated signal.
4. The method of claim 1 wherein the method further comprises determining the FFP for the FBE channel access mode.
5. The method of claim 4 wherein determining the FFP comprises determining the FFP based on the channel access mode indication.
6. The method of claim 5 wherein the channel access mode indication is a joint indication of the channel access mode and, if the indicated channel access mode is the FBE channel access mode, the FFP.
7. The method of claim 1 wherein the method further comprises determining a start of one or more FFPs for the FBE channel access mode.
8. The method of claim 1 wherein operating in the determined channel access mode comprises operating as an initiating node by:
performing a Clear Channel Access (CCA) check on an operating channel before a start of a particular FFP; and
upon a result of the CCA check being that the operating channel is clear transmitting an UL transmission during the particular FFP.
9. The method of claim 8 further comprising determining the FFP based on one or more of an indication of FFP and a time domain offset, 0, signaled by the network node.
10. The method of claim 8 wherein operating in the determined channel access mode further comprises operating as the initiating node by calculating the FFP based on a duration of planned initiating transmissions.
11. The method of claim 8 wherein when multiple Random Access Channel (RACH) Occasions (ROs) are configured within a Physical RACH (PRACH) configuration period, operating in the determined channel access mode further comprises operating as the initiating node by selecting one of the multiple ROs at a beginning of the FFP for a first PRACH transmission.
12. A wireless communication device comprising:
processing circuitry configured to cause the wireless communication device to:
receive from a network node, a channel access mode indication, the channel access mode indication being an indication of whether the wireless communication device is to operate in a Frame-Based Equipment (FBE) channel access mode or a Load-Based Equipment (LBE) channel access mode;
determine a channel access mode in which to operate based on the channel access mode indication, wherein the determined channel access mode is the FBE channel access mode, and operating in the determined channel access mode comprises operating as a responding node by:
determining whether a Downlink (DL) transmission is received during a particular Fixed Frame Period (FFP); and
upon determining that the DL transmission is received during the particular FFP, transmitting an Uplink (UL) transmission in the particular FFP; and
operate in the determined channel access mode.
13. A method performed by a network node that implements at least a part of a base station, the method comprising:
transmitting or initiating transmission of a channel access mode indication to one or more wireless communication devices, the channel access mode indication being an indication of whether the one or more wireless communication devices are to operate in a Frame-Based Equipment (FBE) channel access mode or a Load-Based Equipment (LBE) channel access mode, wherein the indicated channel access mode being the FBE channel access mode indicating that the one or more wireless communication devices are to operate as a responding node by:
determining whether a Downlink (DL) transmission is received during a particular Fixed Frame Period (FFP); and
upon determining that the DL transmission is received during the particular FFP, transmitting an Uplink (UL) transmission in the particular FFP.
14. The method of claim 13 wherein the channel access mode indication is a joint indication of a channel access mode and, if the indicated channel access mode is the FBE channel access mode, the FFP for the FBE channel access mode.
15. The method of claim 13 wherein the indicated channel access mode is the FBE channel access mode, and the method further comprises:
configuring or scheduling UL transmissions for the one or more wireless communication devices such that the UL transmissions align with a start of a FFP;
determining whether a UL transmission is detected at a start of a particular FFP; and
upon determining that the UL transmission is detected at the start of the particular FFP, transmitting a DL transmission in the particular FFP.
16. The method of claim 13 further comprising:
configuring a Physical Random Access Channel (PRACH) with multiple Random Access Channel Occasions (ROs); and
aligning a FFP for the FBE channel access mode with the configured PRACH such that at least one of the multiple ROs is at the start of the FFP.
17. A network node comprising:
processing circuitry configured to cause the network node to:
transmit or initiate transmission of a channel access mode indication to one or more wireless communication devices, the channel access mode indication being an indication of whether the one or more wireless communication devices are to operate in a Frame-Based Equipment (FBE) channel access mode or a Load-Based Equipment (LBE) channel access mode, wherein the indicated channel access mode being the FBE channel access mode indicating that the one or more wireless communication devices are to operate as a responding node by:
determining whether a Downlink (DL) transmission is received during a particular Fixed Frame Period (FFP); and
upon determining that the DL transmission is received during the particular FFP, transmitting an Uplink (UL) transmission in the particular FFP.