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EP-4738986-A1 - TERMINAL AND COMMUNICATION METHOD

EP4738986A1EP 4738986 A1EP4738986 A1EP 4738986A1EP-4738986-A1

Abstract

A terminal includes: a reception unit configured to receive a broadcast signal from another terminal; and a transmission unit configured to transmit, to the another terminal, a request signal for becoming a subordinate. The reception unit receives, from the another terminal, an indication indicating that the terminal is to be a subordinate of the another terminal.

Inventors

  • YOSHIOKA, Shohei
  • SHICHIJO, Taichi
  • NAGATA, SATOSHI

Assignees

  • NTT DOCOMO, INC.

Dates

Publication Date
20260506
Application Date
20230629

Claims (6)

  1. A terminal comprising: a reception unit configured to receive a broadcast signal from another terminal; and a transmission unit configured to transmit, to the another terminal, a request signal for becoming a subordinate, wherein the reception unit receives, from the another terminal, an indication indicating that the terminal is to be a subordinate of the another terminal.
  2. The terminal as claimed in claim 1, wherein the transmission unit transmits a communication request to at least one of the another terminal, a base station, or a core network function, and the reception unit receives scheduling information from at least one of the another terminal, the base station, or the core network function.
  3. The terminal as claimed in claim 1, wherein the reception unit and the transmission unit do not perform direct communication with a base station.
  4. The terminal as claimed in claim 1, wherein the transmission unit transmits, to at least one of the another terminal, a base station, or a core network function, information related to requirements for communication with the another terminal.
  5. The terminal as claimed in claim 1, wherein in a case where the reception unit cannot receive a signal from the another terminal for a certain period, the terminal ceases to be the subordinate of the another terminal.
  6. A communication method performed by a terminal, the communication method comprising: receiving a broadcast signal from another terminal; transmitting, to the another terminal, a request signal for becoming a subordinate; and receiving, from the another terminal, an indication indicating that the terminal is to be a subordinate of the another terminal.

Description

TECHNICAL FIELD The present invention relates to a terminal and a communication method in a wireless communication system. BACKGROUND ART 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 Literature 1). The D2D reduces traffic between a terminal and a base station and enables communication between the terminals even when base stations are unable to communicate during a disaster, etc. It is to be noted that although the D2D is referred to as "sidelink" in the 3GPP (registered trademark) (3rd Generation Partnership Project), the more generic term D2D is used in the present description. 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, they are simply called D2D. In addition, a signal transmitted and received in the D2D is referred to as a D2D signal. Various use cases of V2X (Vehicle to Everything) services in NR are being discussed (e.g., Non-Patent Literature 2). In addition, in NR Release 17 (for example, Non-Patent Literature 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. 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 performed at the time of channel access (for example, Non-Patent Literature 4). In the higher frequency band, in a case of performing D2D communication, an operation adapted to the regulations in the unlicensed band is required. CITATION LIST Non-Patent Literature Non-Patent Literature 1: 3GPP TS 38.211 V17.4.0 (2022-12)Non-Patent Literature 2: 3GPP TR 22.886 V16.2.0 (2018-12)Non-Patent Literature 3: 3GPP TS 38.306 V17.3.0 (2022-12)Non-Patent Literature 4: 3GPP TS 37.213 V17.4.0 (2022-12) SUMMARY OF INVENTION TECHNICAL PROBLEM In NR sidelink, mode 1 and mode 2 are specified as resource determination methods, the mode 1 being a method in which the base station schedules resource allocation for a terminal, and the mode 1 being a method in which the terminal autonomously selects a resource. In the future, in order to achieve sidelink communications used for various qualities of use cases by various UE types, an efficient control by the network is expected to be introduced. The present invention has been made in view of the foregoing and is intended to implement an efficient sidelink communications based on the control by the network. SOLUTION TO PROBLEM According to the disclosed technique, a terminal is provided. The terminal includes: a reception unit configured to receive a broadcast signal from another terminal; and a transmission unit configured to transmit, to the another terminal, a request signal for becoming a subordinate, based on the broadcast signal. The reception unit receives, from the another terminal, an indication indicating that the terminal is to be a subordinate of the another terminal. ADVANTAGEOUS EFFECTS OF INVENTION According to the disclosed technique, the efficient sidelink communications can be implemented based on the control by the network. BRIEF DESCRIPTION OF DRAWINGS [Fig. 1] is a drawing for describing V2X.[Fig. 2] is a sequence diagram illustrating an operation example (1) of V2X.[Fig. 3] is a sequence diagram illustrating an operation example (2) of V2X.[Fig. 4] is a sequence diagram illustrating an operation example (3) of V2X.[Fig. 5] is a sequence diagram illustrating an operation example (4) of V2X.[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 describing a