Method and apparatus for frame based equipment operation of NR unlicensed

Patent metadata

Field	Value
Publication number	US-11140708-B2
Application number	US-201916522588-A
Country	US
Kind code	B2
Filing date	Jul 25, 2019
Priority date	Jul 30, 2018
Publication date	Oct 5, 2021
Grant date	Oct 5, 2021

Abstract

A user equipment (UE) includes at least one processor configured to identify a channel access mechanism to gain access to an operating channel of unlicensed band, perform a listen-before-talk (LBT) operation over the operating channel according to the identified channel access mechanism and obtain a channel occupancy time (COT) for transmission and reception on the operating channel after the LBT operation is successful, and identify, within the COT, one or more switching points for the UE to switch from uplink (UL) transmission to downlink (DL) reception or from the DL reception to the UL transmission. The UE further includes a transceiver configured to transmit to or receive from a base station (BS) over the operating channel during the COT, and switch from the UL transmission to the DL reception or from the DL reception to the UL transmission based on the identified one or more switching points.

First claim

What is claimed is:

1. A user equipment (UE) in a wireless communication system, the UE comprising:
at least one processor configured to:
identify a channel access mechanism to gain access to an operating channel of an unlicensed band;
perform a listen-before-talk (LBT) operation over the operating channel according to the identified channel access mechanism and obtain a channel occupancy time (COT) for transmission and reception on the operating channel after the LBT operation is successful;
identify, within the COT, one or more switching points for the UE to switch from
uplink (UL) transmission to downlink (DL) reception or from the DL reception to the UL transmission;
determine whether each of the one or more switching points occurs within a gap after (i) a last DL reception when switching from the DL reception to the UL transmission occurs or (ii) a last UL transmission when switching from the UL transmission to the DL reception occurs; and
in response to each of the one or more switching points occurring within the gap, perform a switching between the DL reception and the UL transmission, without performing an LBT; and

a transceiver operably connected to the at least one processor, the transceiver configured to:
transmit to or receive from a base station (BS) over the operating channel during the COT; and
switch from the UL transmission to the DL reception or from the DL reception to the UL transmission based on the identified one or more switching points.

2. The UE of claim 1 , wherein:
if the identified channel access mechanism is-a load-based equipment (LBE) mode, the processor is configured to identify a configurable sensing duration to obtain an adaptable contention window size for the LBT operation;
if the identified channel access mechanism is a frame-based equipment (FBE) mode, the processor is configured to identify a fixed sensing duration prior to each of periodic fixed frame periods (FFPs) to perform the LBT operation; and
the UE is configured to transmit or receive a transmission within the COT after the LBT operation.

3. The UE of claim 2 , wherein the FBE mode is configured with at least one of:
a length of an FFP that is configurable from a pre-defined set of values in a unit of one millisecond or one slot;
a length of a COT that is configurable with one of a fixed maximum value, a percentage of an FFP, or one of a set of predefined values; or
a starting position of an FFP that is configurable by a time granularity of one of one microsecond, one millisecond, one symbol, or 1/(480 kilo-Hertz (kHz)*4096).

4. The UE of claim 2 , wherein when the identified channel access mechanism is configured with the FBE mode, the processor is further configured to:
perform an LBT over each of a plurality of spatial receive (RX) parameters aligned with intended spatial transmit (TX) parameters simultaneously, and utilize spatial parameters that have passed LBT for transmission during a COT; and
perform an LBT over each of the plurality of spatial RX parameters sequentially over each of time units; or perform an omni-directional LBT by:
if the omni-directional LBT passes, causing the transceiver to send a transmission, or
if the omni-directional LBT does not pass, performing a directional LBT and causing the transceiver to send a transmission over a spatial TX parameter that has passed the directional LBT.

5. The UE of claim 1 , wherein the processor is further configured to:
in response to the each of the one or more switching points occurring outside of the gap:
cause the transceiver to perform an LBT ending prior to each of the one or more switching points; or
extend a cyclic prefix of a perspective UL transmission such that a prospective UL transmission starts within the gap after an end of the last UL transmission,

wherein the gap is a short interframe space (SIFS) duration.

6. The UE of claim 1 , wherein a maximum number of switchings between the UL transmission to the DL reception within the COT is configured to be one of:
a predefined fixed number;
a scalable number which is non-decreasing with respect to the COT;
a scalable number with respect to an LBT priority class that is non-decreasing as a channel access priority decreases; or
a scalable number that is non-decreasing with respect to a fixed frame period.

7. The UE of claim 1 , wherein a maximum allowed number of LBT attempts at each of the one or more switching points between the UL transmission to the DL reception is configured to be one of:
a predefined fixed number; or
a scalable number which is non-decreasing with respect to a duration of a perspective UL transmission after each of the one or more switching points between the UL transmission and the DL reception,
wherein a time interval between adjacent LBT attempts is configurable such that:
a new LBT attempt immediately restarts if a previous LBT attempt fails; a new LBT attempt starts at one of a next symbol boundary, a next mini-slot boundary, or a next slot boundary; or
a new LBT is attempted such that a perspective UL transmission starts at one of the next symbol boundary, the next mini-slot boundary, or the next slot boundary.

8. The UE of claim 1 , wherein the at least one processor is further configured to cause the transceiver to transmit a preamble signal, wherein:
in a frequency domain, the preamble signal is mapped to subcarriers in which subcarrier indexes for which any two adjacent preamble signal elements are mapped to be differed by a same fixed number N; and in a time domain, the preamble signal is transmitted with a periodic repetition pattern with a periodicity of 1/(N*a subcarrier spacing of the preamble signal).

9. A base station (BS) in a wireless communication system, the BS comprising:
at least one processor configured to:
identify a channel access mechanism to gain access to an operating channel of an unlicensed band;
perform a listen-before-talk (LBT) operation over the operating channel according to the identified channel access mechanism and obtain a channel occupancy time (COT) for transmission and reception on the operating channel after the LBT operation is successful;
identify, within the COT, one or more switching points for the BS to switch from downlink (DL) transmission to uplink (UL) reception or from the UL reception to the DL transmission;
determine whether each of the one or more switching points occurs within a gap after (i) a last UL reception when switching from the UL reception to the DL transmission occurs or (ii) a last DL transmission when switching from the DL transmission to the UL reception occurs; and
in response to each of the one or more switching points within the gap, perform a switching between the UL reception and the DL transmission, without performing an LBT; and

a transceiver operably connected to the at least one processor, the transceiver configured to:
transmit to or receive from a user equipment (UE) over the operating channel during the COT; and
switch from the DL transmission to the UL reception or from the UL reception to the DL transmission based on the identified one or more switching points.

10. The BS of claim 9 , wherein:
if the identified channel access mechanism is a load-based equipment (LBE) mode, the processor is configured to identify a configurable sensing duration to obtain an adaptable contention window size for the LBT operation;
if the identified channel access mechanism is a frame-based equipment (FBE) mode, the processor is configured to identify a fixed sensing duration prior to each of periodic fixed frame periods (FFPs) to perform the LBT operation; and
the BS is configured to transmit or receive a transmission within the COT after the

Assignees

• Samsung Electronics Co Ltd

Inventors

• Li Yingzhe
• Si Hongbo
• Lin Qiongjie

Classifications

• H04W74/004 Primary

  in the uplink, i.e. towards network · CPC title

• H04L5/1469

  using time-sharing · CPC title

• H04L5/001

  the frequencies being arranged in component carriers · CPC title

• H04W74/0808 Primary

  using carrier sensing, e.g. carrier sense multiple access [CSMA] · CPC title

• H04L5/0051

  of dedicated pilots, i.e. pilots destined for a single user or terminal · CPC title