Search

US-20260129686-A1 - TERMINAL AND COMMUNICATION METHOD

US20260129686A1US 20260129686 A1US20260129686 A1US 20260129686A1US-20260129686-A1

Abstract

A terminal includes: a control unit configured to determine a method related to LBT (Listen before talk) corresponding to a transmission in a first number of LBT channels and a method related to the transmission; a reception unit configured to perform LBT, based on the method related to LBT; and a transmission unit configured to transmit the transmission to another terminal, based on the method related to the transmission. The control unit determines the method related to LBT and the method related to the transmission, based on a situation of a COT (Channel occupancy time) that is obtained by the another terminal in the first number of LBT channels.

Inventors

  • Shohei Yoshioka
  • Naoya SHIBAIKE
  • Hiroki Harada
  • Satoshi Nagata

Assignees

  • NTT DOCOMO, INC.

Dates

Publication Date
20260507
Application Date
20230830
Priority Date
20221011

Claims (6)

  1. 1 . A terminal comprising: a control unit configured to determine a method related to LBT (Listen before talk) corresponding to a transmission in a first number of LBT channels and a method related to the transmission; a reception unit configured to perform LBT, based on the method related to LBT; and a transmission unit configured to transmit the transmission to another terminal, based on the method related to the transmission, wherein the control unit determines the method related to LBT and the method related to the transmission, based on a situation of a COT (Channel occupancy time) that is obtained by the another terminal in the first number of LBT channels.
  2. 2 . The terminal as claimed in claim 1 , wherein the control unit determines to perform type-2 LBT in a second number of LBT channels in a case where the COT has already been obtained in the second number of LBT channels, the second number being equal to or greater than one and being equal to or less than the first number.
  3. 3 . The terminal as claimed in claim 2 , wherein the control unit determines to perform type-1 LBT in a number of LBT channels, the number being obtained by subtracting the second number from the first number.
  4. 4 . The terminal as claimed in claim 2 , wherein the control unit determines to perform type-1 LBT in one LBT channel among a number of LBT channels, the number being obtained by subtracting the second number from the first number.
  5. 5 . The terminal as claimed in claim 1 , wherein the control unit does not perform the transmission in a case where COT has not been obtained by the another terminal in at least one LBT channel among the first number of LBT channels.
  6. 6 . A communication method performed by a terminal, the communication method comprising: determining a method related to LBT (Listen before talk) corresponding to a transmission in a first number of LBT channels and a method related to the transmission; performing LBT, based on the method related to LBT; transmitting the transmission to another terminal, based on the method related to the transmission; and determining the method related to LBT and the method related to the transmission, based on a situation of a COT (Channel occupancy time) that is obtained by the another terminal in the first number of LBT channels.

Description

FIELD OF THE INVENTION The present invention relates to a terminal and a communication method in a wireless communication system. BACKGROUND OF THE INVENTION In LTE (Long Term Evolution) and LTE successor systems (e.g., LTE-A (LTE Advanced), NR (New Radio) (also referred to as 5G)), a D2D (Device to Device) technology in which terminals communicate directly with each other without using a base station is being discussed (e.g., Non-Patent Document 1). The D2D reduces traffic between the terminals and the base stations and enables communication between the terminals even when the base stations are unable to communicate during a disaster, etc. Although the 3GPP (registered trademark) (3rd Generation Partnership Project) refers to D2D as a “sidelink”, the more generic term D2D is used herein. However, in the description of embodiments described below, sidelink is also used as needed. The D2D communication is broadly classified into: D2D discovery for discovering other terminals capable of communication; and D2D communication (D2D direct communication, device to device direct communication, etc.) for direct communication between terminals. Hereinafter, when D2D communication and D2D discovery are not specifically distinguished, it is simply called D2D. A signal sent and received by D2D is called a D2D signal. Various use cases of V2X (Vehicle to Everything) services in NR have been discussed (e.g., Non-Patent Document 2). In addition, in NR Release 17 (for example, Non-Patent Document 3), use of a frequency band that is higher than that of the conventional releases is being discussed. For example, applicable numerologies including subcarrier spacings, channel bandwidths, etc., physical layer design, and possible failures in actual wireless communication in the 52.6 GHz to 71 GHz frequency band have been discussed. CITATION LIST Non-Patent Document Non-Patent Document 1: 3GPP TS 38.211 V17.1.0 (2022 March)Non-Patent Document 2: 3GPP TR 22.886 V15.1.0 (2017 March)Non-Patent Document 3: 3GPP TS 38.306 V17.0.0 (2022 March)Non-Patent Document 4: 3GPP TS 37.213 V17.1.0 (2022 March) SUMMARY OF THE INVENTION Technical Problem In a newly-operated frequency band in which higher frequencies that are higher than conventional frequencies are used, an unlicensed band is defined. In the unlicensed band, various regulations are specified, and, for example, an LBT (Listen before talk) is to be performed at the time of channel access. In the higher frequency band, in a case of performing a D2D communication, an operation adapted to the regulations in the unlicensed band is required. Here, there is a case in which an operation related to the COT (Channel occupancy time) sharing is unclear in the LBT of the device-to-device direct communication. The present invention has been made in view of the above points, and an object is to perform COT (Channel occupancy time) sharing of the device-to-device direct communication that is adapted to the regulations in an unlicensed band. Solution to Problem According to the disclosed technique, a terminal is provided. The terminal includes: a control unit configured to determine a method related to LBT (Listen before talk) corresponding to a transmission in a first number of LBT channels and a method related to the transmission; a reception unit configured to perform LBT, based on the method related to LBT; and a transmission unit configured to transmit the transmission to another terminal, based on the method related to the transmission. The control unit determines the method related to LBT and the method related to the transmission, based on a situation of a COT (Channel occupancy time) that is obtained by the another terminal in the first number of LBT channels. Advantageous Effects of Invention According to the disclosed technique, the COT (Channel occupancy time) sharing of the device-to-device communication that is adapted to the regulations in an unlicensed band can be performed. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a drawing for describing V2X. FIG. 2 is a sequence diagram illustrating an example (1) of a V2X operation. FIG. 3 is a sequence diagram illustrating an example (2) of a V2X operation. FIG. 4 is a sequence diagram illustrating an example (3) of a V2X operation. FIG. 5 is a sequence diagram illustrating an example (4) of a V2X operation. FIG. 6 is a drawing illustrating an example of a sensing operation. FIG. 7 is a flowchart for describing an example of a preemption operation. FIG. 8 is a drawing illustrating an example of a preemption operation. FIG. 9 is a drawing illustrating an example of a partial sensing operation. FIG. 10 is a drawing for describing an example of periodic-based partial sensing. FIG. 11 is a drawing for describing an example of contiguous partial sensing. FIG. 12 is a drawing illustrating an example of a frequency range in an embodiment of the present invention. FIG. 13 is a drawing for describing an example (1) of LBT. FIG. 14 is a drawing for des