WO2023013744A1 - Communication device, base station, and communication method - Google Patents

Abstract

A user equipment (100) is a communication device (100) for which a first cell (C1) and a second cell (C2) are configured by a base station (200). The user equipment (100) is provided with: a reception unit (112) for receiving from the base station (200) a timing advance group identifier corresponding to the first cell (C1) and a timing advance group identifier corresponding to the second cell (C2); and a control unit (120) which, upon receiving the timing advance group identifier corresponding to the first cell (C1) and the timing advance group identifier corresponding to the second cell (C2), adjusts a first transmission timing for an uplink signal and a second transmission timing for an uplink signal.

Description

Communication device, base station and communication method Cross-reference to related applications

This application is based on and claims the benefit of priority from patent application number 2021-128562, filed on August 4, 2021, the entire contents of which are incorporated by reference. incorporated herein by.

The present disclosure relates to a communication device, base station and communication method used in a mobile communication system.

In the 3GPP (registered trademark; hereinafter the same) (3rd Generation Partnership Project), which is a standardization project for mobile communication systems, as an extension of MIMO (Multi-Input Multi-Output), multiple transmission/reception point (TRP: Transmission/Reception Point) transmission Introduction is being considered.

In a multi-TRP transmission scenario, a first cell that is a serving cell and a second cell that belongs to the same frequency (intra frequency) as the first cell are configured in a communication device, and the communication device maintains the first cell as a serving cell, A model of performing data communication with the second cell is assumed (see Non-Patent Documents 1 to 3). Here, the second cell is a cell (cell having TRP with different PCI) configured by a TRP different from that of the first cell and having a physical cell identifier (PCI) different from that of the first cell.

By the way, in order to compensate for propagation delay, a communication device located far from a cell transmits an uplink signal at an earlier timing than a communication device located close to the cell. Specifically, the communication device adjusts the transmission timing of the uplink signal based on the timing advance from the base station.

In the multiple TRP transmission scenario described above, it is considered necessary for the communication device to adjust the transmission timing of the uplink signals for each of the first cell and the second cell. However, a method of adjusting the uplink transmission timing for the second cell has not been realized, and there is a concern that the transmission timing of the uplink signal for the second cell cannot be controlled appropriately.

Therefore, in the present disclosure, when the first cell that is the serving cell and the second cell belonging to the same frequency as the first cell are set, communication that can appropriately control the transmission timing of the uplink signal for the second cell An object is to provide an apparatus, a base station and a communication method.

A user equipment (100) according to the first aspect is a communication equipment (100) in which a first cell (C1) and a second cell (C2) are set by a base station (200). The user equipment (100) receives a timing advance group identifier corresponding to the first cell (C1) and a timing advance group identifier corresponding to the second cell (C2) from the base station (200). (112) and the first transmission timing of the uplink signal when receiving the timing advance group identifier corresponding to the first cell (C1) and the timing advance group identifier corresponding to the second cell (C2). and a control unit (120) that adjusts the second transmission timing of the uplink signal.

A base station (200) according to a second aspect configures a first cell (C1), which is a serving cell, and a second cell (C2) belonging to the same frequency as the first cell (C1) in a communication device (100). A base station (200). The base station (200) includes a control unit (230) for determining whether the first cell (C1) and the second cell (C2) belong to the same timing advance group; ) and the second cell (C2) belong to the same timing advance group to the communication device (100).

In the communication method according to the third aspect, the first It is a communication method executed by a communication device (100) in which a cell (C1) and the second cell (C2) are set. The communication method includes receiving group information from the base station (200) indicating whether the first cell (C1) and the second cell (C2) belong to the same timing advance group; adjusting the transmission timing of uplink signals to said second cell (C2) based on the information.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.
1 is a diagram showing the configuration of a mobile communication system according to an embodiment; FIG. 1 is a diagram showing a configuration example of a protocol stack in a mobile communication system according to an embodiment; FIG. FIG. 4 is an explanatory diagram for explaining the relationship between uplink frames and downlink frames in the mobile communication system according to the embodiment; 1 is a diagram showing an assumed scenario in a mobile communication system according to an embodiment; FIG. FIG. 3 shows a basic procedure in an assumed scenario according to an embodiment; It is a figure which shows the structure of UE which concerns on embodiment. It is a figure which shows the structure of the base station which concerns on embodiment. FIG. 4 is a diagram showing a sequence of a first operation example in the mobile communication system according to the embodiment; FIG. 4 is an explanatory diagram for explaining a first operation example in the mobile communication system according to the embodiment; FIG. 7 is a diagram showing a sequence of a second operation example in the mobile communication system according to the embodiment; FIG. 5 is an explanatory diagram illustrating a second operation example in the mobile communication system according to the embodiment;

A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

(Configuration of mobile communication system)
A configuration of a mobile communication system 1 according to an embodiment will be described with reference to FIG. The mobile communication system 1 is, for example, a system conforming to 3GPP Technical Specifications (TS). Hereinafter, as the mobile communication system 1, a mobile communication system based on the 3GPP standard 5th Generation System (5GS), that is, NR (New Radio) will be described as an example.

The mobile communication system 1 has a network 10 and a communication device (User Equipment: UE) 100 that communicates with the network 10 . The network 10 includes an NG-RAN (Next Generation Radio Access Network) 20, which is a 5G radio access network, and a 5GC (5G Core Network) 30, which is a 5G core network.

　UE 100 is a device used by a user. The UE 100 is, for example, a portable device such as a mobile phone terminal such as a smart phone, a tablet terminal, a notebook PC, a communication module, or a communication card. The UE 100 may be a vehicle (eg, car, train, etc.) or a device provided therein. The UE 100 may be a transport body other than a vehicle (for example, a ship, an airplane, etc.) or a device provided thereon. The UE 100 may be a sensor or a device attached thereto. Note that the UE 100 includes a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, and a remote terminal. , remote device, or remote unit.

NG-RAN 20 includes multiple base stations 200 . Each base station 200 manages at least one cell. A cell constitutes the minimum unit of a communication area. For example, one cell belongs to one frequency (carrier frequency) and is configured by one component carrier. The term “cell” may represent a radio communication resource and may also represent a communication target of UE 100 . Each base station 200 can perform radio communication with the UE 100 residing in its own cell. The base station 200 communicates with the UE 100 using the RAN protocol stack. Base station 200 provides NR user plane and control plane protocol termination towards UE 100 and is connected to 5GC 30 via NG interface. Such an NR base station 200 is sometimes referred to as a gNodeB (gNB).

The 5GC 30 includes a core network device 300. The core network device 300 includes, for example, AMF (Access and Mobility Management Function) and/or UPF (User Plane Function). AMF performs mobility management of UE100. UPF provides functions specialized for user plane processing. The AMF and UPF are connected with the base station 200 via the NG interface.

A configuration example of a protocol stack in the mobile communication system 1 according to the embodiment will be described with reference to FIG.

The protocol of the radio section between the UE 100 and the base station 200 includes a physical (PHY) layer, a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, It has an RRC (Radio Resource Control) layer.

The PHY layer performs encoding/decoding, modulation/demodulation, antenna mapping/demapping, and resource mapping/demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the base station 200 via physical channels.

A physical channel is composed of multiple OFDM (Orthogonal Frequency Division Multiplexing) symbols in the time domain and multiple subcarriers in the frequency domain. One subframe consists of a plurality of OFDM symbols in the time domain. A resource block is a resource allocation unit, and is composed of a plurality of OFDM symbols and a plurality of subcarriers. A frame may consist of 10 ms and may include 10 subframes of 1 ms. A subframe can include a number of slots corresponding to the subcarrier spacing.

Among physical channels, the physical downlink control channel (PDCCH) plays a central role, for example, for purposes such as downlink scheduling assignments, uplink scheduling grants, and transmission power control.

In NR, the UE 100 can use a narrower bandwidth than the system bandwidth (that is, the cell bandwidth). The base station 200 sets a bandwidth part (BWP) consisting of consecutive PRBs (Physical Resource Blocks) for the UE 100 . UE 100 transmits and receives data and control signals on the active BWP. Up to four BWPs can be set in the UE 100, for example. Each BWP may have different subcarrier spacing and may overlap each other in frequency. If multiple BWPs are configured for the UE 100, the base station 200 can specify which BWP to activate through downlink control. This allows the base station 200 to dynamically adjust the UE bandwidth according to the amount of data traffic of the UE 100, etc., and reduce UE power consumption.

For example, the base station 200 can configure up to 3 control resource sets (CORESET) for each of up to 4 BWPs on the serving cell. CORESET is a radio resource for control information that the UE 100 should receive. UE 100 may be configured with up to 12 CORESETs on the serving cell. Each CORESET has an index from 0 to 11. For example, a CORESET consists of 6 resource blocks (PRBs) and 1, 2 or 3 consecutive OFDM symbols in the time domain.

The MAC layer performs data priority control, retransmission processing by hybrid ARQ (HARQ: Hybrid Automatic Repeat reQuest), random access procedures, and the like. Data and control information are transmitted between the MAC layer of the UE 100 and the MAC layer of the base station 200 via transport channels. The MAC layer of base station 200 includes a scheduler. The scheduler determines uplink and downlink transport formats (transport block size, modulation and coding scheme (MCS)) and allocation resources to the UE 100 .

The RLC layer uses the functions of the MAC layer and PHY layer to transmit data to the RLC layer on the receiving side. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the base station 200 via logical channels.

The PDCP layer performs header compression/decompression and encryption/decryption.

An SDAP (Service Data Adaptation Protocol) layer may be provided as an upper layer of the PDCP layer. The SDAP (Service Data Adaptation Protocol) layer performs mapping between an IP flow, which is the unit of QoS control performed by the core network, and a radio bearer, which is the unit of QoS control performed by the AS (Access Stratum).

The RRC layer controls logical channels, transport channels and physical channels according to radio bearer establishment, re-establishment and release. RRC signaling for various settings is transmitted between the RRC layer of UE 100 and the RRC layer of base station 200 . When there is an RRC connection between the RRC of UE 100 and the RRC of base station 200, UE 100 is in the RRC connected state. If there is no RRC connection between the RRC of the UE 100 and the RRC of the base station 200, the UE 100 is in RRC idle state. When the RRC connection between the RRC of UE 100 and the RRC of base station 200 is suspended, UE 100 is in RRC inactive state.

The NAS layer located above the RRC layer performs session management and mobility management for UE100. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the core network device 300 (AMF). Note that the UE 100 has an application layer and the like in addition to the radio interface protocol.

(Method for adjusting uplink transmission timing)
An example of a method for adjusting uplink transmission timing in the mobile communication system 1 according to the embodiment will be described with reference to FIG. That is, a method for synchronizing uplink transmission timing will be described.

The base station 200 controls the transmission timing of the uplink signal of each UE 100 in order to keep the reception timing of the uplink signal from each UE 100 within the managed cell within a predetermined time range. The base station 200 determines a timing advance (hereinafter referred to as TA) for the UE 100 to adjust the transmission timing of the uplink signal. The base station 200 provides each UE 100 with the determined TA.

The UE 100 adjusts the timing of uplink transmission based on the downlink frame timing. The UE 100 uses TAs to adjust uplink frame timing for downlink frames. As shown in FIG. 4, the UE 100 shifts the i-th uplink frame forward with respect to the i-th downlink frame by a time of (N _TA +N _TA,offset ) _Tc . The UE 100 calculates an adjustment value (T _TA ) for shifting the downlink frame, for example, using the following formula.

N _TA is a value (hereinafter referred to as a TA value) calculated based on the TA (T _A ) notified from the base station 200 (cell). _NTA can be calculated by Equations 2 and 3.

TA (T _A ) in Equation 2 is the value of the timing advance command (TA command) contained in the medium access control (MAC) control element (CE). Upon receiving the TA command, the UE 100 calculates a new TA value (N TA — _NEW ) from the retained TA value (N TA _{— old} ). T _A (T _A ) in Equation 3 is the timing advance value included in the random access response. Note that μ is the subcarrier interval setting.

N _TA,offset is a fixed offset value used to calculate the adjustment value (T _TA ). N _TA,offset may be notified from the base station 200 (cell). If the UE 100 is not notified of the N _{TA, offset} from the base station 200, the UE 100 may determine the N _{TA, offset} as a default value. The UE 100 may determine the offset value (N _TA,offset ) based on conditions such as the frequency band, presence or absence of MR-DC, and presence or absence of coexistence of NR/NB-IoT. The UE 100 may, for example, determine the offset value (N _TA,offset ) using Table 1 below.

_Tc is the basic time unit. _Tc is a predetermined fixed value. The UE 100 holds information on _Tc in advance. _Tc is, for example, 0.509 ns.

The downlink frame timing, which is the reference for adjusting the timing of uplink transmission, is the timing at the beginning of the downlink frame. Specifically, the downlink frame timing is defined as the time at which the first detected path (in time) of the downlink frame is received from the base station 200 (specifically, the reference cell). A radio frame constituting an uplink frame and a downlink frame is composed of ten subframes of 1 ms. Each frame is divided into two equally sized half-frames of 5 sub-frames.

The UE 100 synchronizes the downlink timing using the synchronization signal included in the reference signal (SSB: SS/PBCH Block) transmitted in the BWP, thereby grasping the downlink frame timing in the BWP that received the SSB. can.

The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH (Physical Broadcast Channel), and a demodulation reference signal (DMRS). For example, an SSB may consist of four consecutive OFDM symbols in the time domain. Also, the SSB may consist of 240 consecutive subcarriers (ie, 20 resource blocks) in the frequency domain. PBCH is a physical channel that carries a Master Information Block (MIB).

(Assumed scenario)
An assumed scenario in the mobile communication system 1 according to the embodiment will be described with reference to FIG.

The base station 200 has a TRP 201 # 1 , a TRP 201 # 2 , a DU (Distributed Unit) 202 and a CU (Central Unit) 203 . Although FIG. 4 shows an example in which base station 200 is separated into DU202 and CU203, base station 200 may not be separated into DU202 and CU203. Also, although an example in which the number of TRPs 201 in base station 200 is two is shown, the number of TRPs 201 in base station 200 may be three or more.

The TRPs 201#1 and TRPs 201#2 are distributed and constitute different cells. Specifically, TRP 201#1 forms cell C1 and TRP 201#2 forms cell C2.

Cell C1 and cell C2 belong to the same frequency. Cell C1 and cell C2 have different physical cell identifiers (PCI). That is, the cell C2 is a cell (cell having TRP with different PCI) configured by a TRP #2 different from the TRP 201 #1 corresponding to the cell C1 and having a PCI different from that of the cell C1. Although FIG. 4 shows an example in which the coverage of cell C2 is within the coverage of cell C1, the coverage of cell C2 may at least partially overlap the coverage of cell C1.

DU202 controls TRP201#1 and TRP201#2. In other words, TRP201#1 and TRP201#2 are under the same DU202. The DU 202 is a unit that includes lower layers included in the protocol stack described above, such as the RLC layer, the MAC layer and the PHY layer. DU202 is connected with CU203 via F1 interface which is a fronthaul interface.

CU203 controls DU202. The CU 203 is a unit including upper layers included in the protocol stack described above, such as the RRC layer, the SDAP layer and the PDCP layer. The CU 203 is connected to the core network (5GC 30) via the NG interface, which is a backhaul interface.

The UE 100 is in the RRC connected state and performs wireless communication with the base station 200. NR is capable of wideband transmission in a high frequency band such as a millimeter wave band. It has high beam gain. Base station 200 and UE 100 establish a beam pair.

The UE 100 performs data communication with the serving cell C1 (TRP201#1). Specifically, the UE 100 performs data communication with the cell C1 using a beam corresponding to transmission configuration indicator (TCI) state #1. UE 100 is configured with cell 2, which is a non-serving cell, in addition to cell C1. For example, in the UE 100, an SSB (SS/PBCH Block) for performing beam measurement for cell C2 and a radio resource for performing data communication with cell 2 are configured from cell C1.

The UE 100 reports the beam measurement results for the cell C2 to the cell C1. Base station 200 (DU 202) receives beam measurements from UE 100 in cell C1 and activates TCI state #2 corresponding to beams in cell C2 based on the beam measurements.

Thus, in the embodiment, in a multiple TRP transmission scenario, cell C1, which is a serving cell, and cell C2 belonging to the same frequency (intra frequency) as cell C1 are configured in UE 100, and UE 100 maintains cell C1 as a serving cell. A model in which data communication is performed with the cell C2 is assumed.

A basic procedure in an assumed scenario according to the embodiment will be described with reference to FIG.

In step S1, the UE 100 receives configuration information from the cell C1 (TRP201#1) by, for example, RRC signaling. The setting information includes SSB settings used for beam measurement for cell C2 (TRP201#2) and settings necessary for using radio resources for data transmission/reception (including data transmission/reception with cell C2). Configuration information may be transmitted from CU 203 to UE 100 via DU 202 and cell C1 (TRP 201 #1).

In step S2, UE 100 performs beam measurement for cell C2 (TRP201#2) using the setting information (in particular, SSB setting) received in step S1 (step S2a), and sends a report including the measurement result to cell C1 (TRP201 #1) (step S2b). DU 202 receives beam measurement results via cell C1 (TRP 201#1).

In step S3, DU 202 sends an instruction to activate the TCI state associated with cell C2 (TRP201 #2) based on the beam measurement results received in step S2 via cell C1 (TRP201 #1) It transmits to UE100. Such an activation indication is performed by layer 1 (PHY layer) and layer 2 (MAC layer, etc.) signaling. The UE 100 activates the TCI state associated with the cell C2 (TRP201#2) in response to receiving the activation instruction from the cell C1. As a result, a beam pair is established between the UE 100 and the cell C2 (TRP201#2).

In step S4, the UE 100 transmits and receives data to and from the cell C2 (TRP201#2) using the UE dedicated channel on the cell C2 (TRP201#2). DU 202 transmits and receives data to and from UE 100 via cell C2 (TRP 201 #2).

Note that the UE 100 is within the coverage of the cell C1 (TRP201#1) and receives the broadcast channel (BCCH) and paging channel (PCH), which are common channels, from the cell C1 (TRP201#1).

According to such a scenario and procedure, the UE 100 can switch from cell C1 (TRP201 #1) to cell C2 (TRP201 #2) without depending on a switching instruction from a higher layer (in particular, the RRC layer). Data communication can be switched from cell C1 (TRP201#1) to cell C2 (TRP201#2) by beam management in layer 1 (PHY layer) and layer 2 (MAC layer, etc.) without handover. That is, a cell for data communication can be realized by beam switching between layer 1 (PHY layer) and layer 2 (MAC layer, etc.).

In the above scenario, it is considered necessary for the UE 100 to adjust the transmission timing of uplink signals for each of cell C1 (TRP201#1) and cell C2 (TRP201#2). However, a method for adjusting the uplink transmission timing for cell C2 (TRP201#2) has not been realized, and there is concern that the transmission timing of uplink signals for cell C2 (TRP201#2) cannot be appropriately controlled. In one embodiment described later, a method for appropriately controlling the transmission timing of uplink signals for cell C2 (TRP201#2) will be described.

Also, in the above scenario, in order to adjust the transmission timing of the uplink signal to cell C2 (TRP201 #2), the UE 100 needs to determine the offset value (N _{TA, offset} ) to be given to the timing advance. . However, the method by which the UE 100 determines the offset value (N _TA,offset ) is not defined. In one embodiment described later, a method for the UE 100 to appropriately determine the offset value for adjusting the transmission timing of the uplink signal to the cell C2 (TRP201#2) will be described.

(Configuration of communication device)
A configuration of the UE 100 according to the embodiment will be described with reference to FIG. UE 100 includes communication unit 110 and control unit 120 .

The communication unit 110 performs wireless communication with the base station 200 by transmitting and receiving wireless signals to and from the base station 200 . The communication unit 110 has at least one transmitter 111 and at least one receiver 112 . The transmitter 111 and receiver 112 may be configured to include multiple antennas and RF circuits. The antenna converts a signal into radio waves and radiates the radio waves into space. Also, the antenna receives radio waves in space and converts the radio waves into signals. The RF circuitry performs analog processing of signals transmitted and received through the antenna. The RF circuitry may include high frequency filters, amplifiers, modulators, low pass filters, and the like.

The control unit 120 performs various controls in the UE 100. Control unit 120 controls communication with base station 200 via communication unit 110 . The operations of the UE 100 described above and below may be operations under the control of the control unit 120 . The control unit 120 may include at least one processor capable of executing a program and a memory that stores the program. The processor may execute a program to operate the control unit 120 . The control unit 120 may include a digital signal processor that performs digital processing of signals transmitted and received through the antenna and RF circuitry. The digital processing includes processing of the protocol stack of the RAN. Note that the memory stores programs executed by the processor, parameters related to the programs, and data related to the programs. The memory may include at least one of ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), RAM (Random Access Memory), and flash memory. All or part of the memory may be included within the processor.

In one embodiment, in the UE 100, the cell C1 ( TRP 201#1) and cell C2 (TRP 201#2) are set. The receiving unit 112 receives group information indicating whether cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group from the base station (200). The control unit 120 adjusts the transmission timing of the uplink signal to cell C2 (TRP201#2) based on the group information. This makes it possible to appropriately control the transmission timing of uplink signals for cell C2 (TRP201#2).

In one embodiment, in the UE 100, the cell C1 ( TRP 201#1) and cell C2 (TRP 201#2) are set. The control unit 120 controls the first transmission timing, which is the transmission timing of the uplink signal to the cell C1 (TRP201#1), and the second transmission timing, which is the transmission timing of the uplink signal to the cell C2 (TRP201#2). , to adjust. The transmitter 111 transmits an uplink signal to cell C1 (TRP201#1) at the first transmission timing, and transmits an uplink signal to cell C2 (TRP201#2) at the second transmission timing. A control unit (120) determines a first offset value to be added to a value based on the first timing advance used for adjusting the first transmission timing, and assigns the first offset value to the second timing advance used for adjusting the second transmission timing. The determined first offset value is used as the second offset value to be given to the base value. This allows the UE 100 to appropriately determine the second offset value and appropriately control the transmission timing of the uplink signal for the cell C2 (TRP201#2).

(Base station configuration)
The configuration of the base station 200 according to the embodiment will be described with reference to FIG. The base station 200 has a plurality of TRPs 201 (TRP 201 # 1 and TRP 201 # 2 in the example of FIG. 7), a communication section 210 , a network interface 220 and a control section 230 .

Each TRP 201 includes multiple antennas and is configured to enable beamforming. TRP 201 may also be referred to as a panel or antenna panel. The antenna converts a signal into radio waves and radiates the radio waves into space. Also, the antenna receives radio waves in space and converts the radio waves into signals. Each TRP 201 is arranged in a distributed manner and constitutes a cell.

For example, the communication unit 210 receives radio signals from the UE 100 and transmits radio signals to the UE 100. The communication unit 210 has at least one transmitter 211 and at least one receiver 212 . The transmitting section 211 and the receiving section 212 may be configured including an RF circuit. The RF circuitry performs analog processing of signals transmitted and received through the antenna. The RF circuitry may include high frequency filters, amplifiers, modulators, low pass filters, and the like.

The network interface 220 transmits and receives signals to and from the network. The network interface 220, for example, receives signals from adjacent base stations connected via an Xn interface, which is an interface between base stations, and transmits signals to adjacent base stations. Also, the network interface 220 receives signals from the core network device 300 connected via the NG interface, for example, and transmits signals to the core network device 300 .

The control unit 230 performs various controls in the base station 200. The control unit 230 controls communication with the UE 100 via the communication unit 210, for example. Also, the control unit 230 controls communication with nodes (for example, adjacent base stations, core network device 300) via the network interface 220, for example. The operations of the base station 200 described above and below may be operations under the control of the control unit 230 . The control unit 230 may include at least one processor capable of executing programs and a memory storing the programs. The processor may execute a program to operate the controller 230 . Control unit 230 may include a digital signal processor that performs digital processing of signals transmitted and received through the antenna and RF circuitry. The digital processing includes processing of the protocol stack of the RAN. Note that the memory stores programs executed by the processor, parameters related to the programs, and data related to the programs. All or part of the memory may be included within the processor.

In addition, when the base station 200 is separated into the DU202 and the CU203, the communication unit 210 may be provided in the DU202, and the control unit 230 may be provided in the DU202 and/or the CU203.

In one embodiment, the base station 200 (control unit 230) configures the UE 100 with cell C1 (TRP201#1), which is a serving cell, and cell C2 (TRP201#2) belonging to the same frequency as cell C1 (TRP201#1). . Control section 230 determines whether or not cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group. Transmitting section 211 transmits to UE 100 group information indicating whether or not cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group. Thereby, the UE 100 can grasp whether the cell C1 (TRP201#1) and the cell C2 (TRP201#2) belong to the same timing advance group, and the transmission timing of the uplink signal for the cell C2 (TRP201#2). can be controlled appropriately.

(system operation)
(1) First Operation Example A first operation example in the mobile communication system 1 will be described with reference to FIGS. 8 and 9. FIG. In the first operation example, UE 100 transmits an uplink signal to cell C2 based on group information indicating that cell C1 (TRP201 #1) and cell C2 (TRP201 #2) belong to the same timing advance group. Adjust timing.

In step S101, the base station 200 (transmitting section 211) sets the first timing advance (first TA) for adjusting the transmission timing of the uplink signal to the cell C1 (TRP201#1) to the cell C1 (TRP201#1). to the UE 100 in. UE 100 (receiving section 112) receives the first TA from cell C1 (TRP 201 #1).

The base station 200 (transmitting section 211) may transmit the first TA by MAC CE, or in random access, by responding to the random access (RA) preamble (RA response) from the UE 100.

In step S102, the UE 100 (control unit 120) determines the first adjustment value (T _TA1 ). A first adjustment value (T _TA1 ).

The UE 100 (control unit 120) calculates the first TA value (N _TA1 ) based on the first TA (T _A1 ) using Equation 2 or Equation 3, for example. Also, the UE 100 (control unit 120) may determine the first offset value (N _TA,offset ) to be given to the first TA value. The UE 100 (control unit 120) may determine the first adjustment value (T _TA1 ) from the first TA value and the determined first offset value using Equation 1 above.

The UE 100 (control unit 120) uses the downlink timing from the cell C1 (TRP 201#1) as a timing reference for the first uplink transmission (hereinafter, appropriately referred to as a first timing reference). As shown in FIG. 9, UE 100 (control section 120) determines the timing shifted by the first adjustment value (T _TA1 ) determined from the first timing reference as the first transmission timing.

In step S103, the UE 100 (transmitting section 111) transmits the first uplink signal to the cell C1 (TRP201#1) at the determined first transmission timing. The base station 200 (receiving section 212) receives an uplink signal in cell C1 (TRP 201#1).

After that, the base station 200 (control unit 230) starts an operation for performing data communication with the cell C2 (TRP201#2) while the UE100 maintains the cell C1 (TRP201#1) as a serving cell.

The base station 200 (control unit 230) determines whether cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group.

For example, when both the following conditions (a) and (b) are satisfied, the base station 200 (control unit 230) places cell C1 (TRP201#1) and cell C2 (TRP201#2) in the same timing advance group. may be determined to belong. When at least one of the conditions (a) and (b) is not satisfied, the base station 200 (control unit 230) determines that the cell C1 (TRP201#1) and the cell C2 (TRP201#2) belong to different timing advance groups. can be determined.

(a) Second adjustment value for adjusting the transmission timing (hereinafter referred to as second transmission timing) of the uplink signal (hereinafter referred to as second uplink signal) to cell C2 (TRP201#2) When the first TA can be applied as (T _TA2 ) (b) When the first timing reference can be used as the timing reference when adjusting the second transmission timing

Based on the determination result, the base station 200 (control unit 230) generates group information indicating whether cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group. In the group information, for example, by setting a timing advance group identifier for each cell, it may be indicated whether cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group. For example, in the group information, cell C1 (TRP201#1) is associated with timing advance group identifier #1, and cell C2 (TRP201#2) is associated with timing advance group identifier #1. , the group information may indicate that cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group. For example, in the group information, cell C1 (TRP201#1) is associated with timing advance group identifier #1, and cell C2 (TRP201#2) is associated with timing advance group identifier #2. , the group information may indicate that cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to different timing advance groups. In this operation example, the base station 200 (control unit 230) determines that cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group. Therefore, the group information indicates that cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group.

In step S104, the base station 200 (transmitting section 211) transmits group information to the UE 100 in the cell C1 (TRP201#1). UE 100 (receiving section 112) receives group information from cell C1 (TRP 201 #1).

The base station 200 (transmitting section 211) may transmit the group information to the UE 100 in the cell C1 (TRP201#1) during steps S1 to S4 in the procedure shown in FIG. The base station 200 (transmitting section 211) transmits, to the UE 100, configuration information including, for example, group information and beam measurement configuration information for configuring beam measurement reference signals used for beam measurement for cell C2 (TRP 201 #2). you can UE 100 (receiving section 112) receives group information and beam measurement configuration information from cell C1 (TRP 201 #1). As a result, whether or not the second transmission timing can be adjusted using the first TA as described later before the UE 100 transmits/receives data to/from the cell C2 (TRP201#2) (that is, step S4 in FIG. 5) can be determined. Also, signaling between the UE 100 and the base station 200 can be reduced compared to the case of transmitting the group information and the beam measurement configuration information separately.

The beam measurement setting information includes reference signal information indicating the SSB or channel state information reference signal (CSI-RS) transmitted by cell C2 (TRP201#2).

Note that the base station 200 (transmitting section 211) may transmit group information to the UE 100 in cell C2 (TRP201#2). UE 100 (receiving section 112) may receive group information from cell C2 (TRP 201 #2).

The UE 100 (control unit 120) adjusts the transmission timing of the uplink signal to cell C2 (TRP201#2) based on the group information. For example, the UE 100 performs the following operations.

In step S105, the UE 100 (control unit 120) determines whether cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group based on the group information.

In this operation example, the UE 100 (control unit 120) uses the cell C1 (TRP201 #1) because the group information indicates that the cell C1 (TRP201 #1) and the cell C2 (TRP201 #2) belong to the same timing advance group. ) and cell C2 (TRP201#2) belong to the same timing advance group.

In step S106, the UE 100 (control unit 120) determines a second adjustment value (T _TA2 ) for adjusting the second transmission timing.

When indicating that cell C1 (TRP201 #1) and cell C2 (TRP201 #2) belong to the same timing advance group, UE 100 (control unit 120) uses the first TA to adjust the second transmission timing. good. That is, the UE 100 (control unit 120) may determine the second adjustment value using the first TA. The UE 100 (control unit 120) may use the first adjustment value as the second adjustment value. This eliminates the need for UE 100 to acquire a second timing advance different from the first TA (hereinafter referred to as a second TA) from base station 200, so signaling between UE 100 and base station 200 can be reduced.

When determining the second adjustment value, the UE 100 (control unit 120) uses the first offset value determined in step S102 as the second offset value (N _{TA, offset} ) while using the first TA as the second TA. may Thereby, the UE 100 can omit the process of determining the second offset value using Table 1, for example. As a result, the processing load on the UE 100 can be reduced.

As shown in FIG. 9, when indicating that cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group, UE 100 (control unit 120) determines the timing of the second uplink transmission. The second transmission timing may be adjusted using the first timing reference as a reference (hereinafter referred to as a second timing reference). Therefore, the UE 100 (control unit 120) may have the same first transmission timing and second transmission timing.

UE 100 (control unit 120) may use the downlink timing from cell C2 (TRP 201#2) as the second timing reference. Therefore, the UE 100 (control unit 120) determines the timing shifted by the determined second adjustment value (T _TA2 ), that is, the first adjustment value (T _TA1 ) from the second timing reference as the second transmission timing. good too.

In this way, the UE 100 (control section 120) adjusts the second transmission timing using the first TA.

Note that the UE 100 (control unit 120) may manage the first TA value and the second TA value independently. That is, the UE 100 (control unit 120) may store the first TA value and the second TA value.

When the UE 100 (control unit 120) receives the first MAC CE including the first TA as the TA command from the base station 200, it may manage the first TA value based on the first MAC CE. That is, the UE 100 (control unit 120) updates the first TA value based on the first TA, and stores the updated first TA value. On the other hand, when the UE 100 (control unit 120) receives the second MAC CE including the second TA as the TA command from the base station 200, it manages the second TA value independently from the first TA value based on the first MAC CE. you can The UE 100 (control unit 120) updates the second TA value based on the second TA and stores the updated second TA value.

Also, the UE 100 (control unit 120) may manage the first adjustment value and the second adjustment value independently. The UE 100 (the control unit 120) may independently manage the information regarding the adjustment of the transmission timing of the uplink signal for each cell.

Also, when using the first TA value as the second TA value, the UE 100 (control unit 120) may store only the first TA value and not the second TA value. Similarly, when using the first adjustment value as the second adjustment value, the UE 100 (control unit 120) may store only the first adjustment value and may not store the second adjustment value.

In step S107, the UE 100 (transmitting section 111) transmits the second uplink signal to the cell C2 (TRP201#2) at the determined second transmission timing. The base station 200 (receiving section 212) receives an uplink signal in cell C2 (TRP 201#2).

Note that when the UE 100 (control unit 120) receives a MAC CE including the first TA as a TA command from the base station 200, the first TA can be used to adjust the second transmission timing in addition to the first transmission timing.

(2) Second Operation Example A second operation example in the mobile communication system 1 will be described with reference to FIGS. 10 and 11, mainly focusing on differences from the above-described operation example. In the second operation example, a case will be described where cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to different timing advance groups.

The operation from step S111 to step S115 is the same as the operation example described above. In this operation example, the base station 200 (control unit 230) generates group information indicating whether cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to the same timing advance group. . Base station 200 (control unit 230) transmits the generated group information to UE 100 in cell C1 (TRP 201 #1).

The UE 100 (control unit 120) determines that cell C1 (TRP201#1) and cell C2 (TRP201#2) belong to different timing advance groups based on the group information.

The UE 100 (control unit 120) may operate to acquire the second TA. UE 100 (control unit 120) may perform random access to cell C2 (TRP 201#2), for example. In random access, UE 100 (transmitting section 111) may transmit a random access (RA) preamble to cell C2 (TRP 201 #2).

In step S116, the base station 200 (transmitting section 211) transmits a second timing advance (second TA) for adjusting the second transmission timing to the UE 100 in cell C1 (TRP201#1). UE 100 (receiving section 112) receives the second TA from cell C1 (TRP 201 #1).

The base station 200 (transmitting section 211) may transmit the second TA by MAC CE, or in random access, by responding to the random access (RA) preamble from the UE 100 (RA response). UE 100 (receiving section 112) may receive the second TA from cell C2 (TRP 201 #2). By receiving the TA (second TA) used for transmission of the second uplink signal from the transmission destination cell of the second uplink signal, it is possible to easily grasp the TA to be applied.

In step S117, the UE 100 (control unit 120) determines a second adjustment value (T _TA2 ) for adjusting the second transmission timing.

The UE 100 (control unit 120) calculates the second TA value (N _TA2 ) based on the second TA (T _A2 ), for example, using Equation 2 or Equation 3 above.

The UE 100 (control unit 120) may determine the second offset value (N _TA,offset ) to be given to the second TA value. The UE 100 (control unit 120) may use the first offset value determined when adjusting the first transmission timing as the second offset value. The UE 100 may manage the first TA value (N _TA1 ) and the second TA value (N _TA2 ) independently and use the first offset value as the second offset value. Thereby, the UE 100 can omit the process of determining the second offset value using Table 1, for example. As a result, the processing load on the UE 100 can be reduced.

UE 100 (control unit 120) may use the first offset value as the second offset value regardless of whether (i) the first TA value and the second TA value are the same, and (ii) the first The first offset value may be used as the second offset value regardless of whether the adjustment value and the second adjustment value are the same; and (iii) the first timing reference and the second timing reference are the same. The first offset value may be used as the second offset value regardless of whether there is, and (iv) the second offset value regardless of whether the transmission timing of the uplink signal after adjustment is the same may be used as the first offset value. Therefore, when cell C2 (TRP201#2) is configured together with cell C1 (TRP201#1), UE 100 can apply the same offset value (N _{TA, offset} ) to both cells.

The UE 100 (control unit 120) may determine the second adjustment value (T _TA2 ) based on the second TA value calculated using Equation 1 above and the second offset value determined.

When the group information indicates that cell C1 (TRP201 #1) and cell C2 (TRP201 #2) belong to different timing advance groups, UE 100 (control section 120) performs downlink from cell C2 (TRP201 #2). The timing may be used as a second timing reference to adjust the second transmission timing. Specifically, as shown in FIG. 11, the UE 100 (control unit 120) determines the second transmission timing to be the timing shifted by the determined second adjustment value (T _TA2 ) from the second timing reference. In this way, the UE 100 (control section 120) adjusts the second transmission timing using the second TA. This allows the network to flexibly set the second transmission timing of the UE 100 (control unit 120).

The operation of step S118 is the same as the operation example described above.

(Other embodiments)
The operation sequences (and operation flows) in the above-described embodiments do not necessarily have to be executed in chronological order according to the order described in the flow diagrams or sequence diagrams. For example, the steps in the operations may be performed out of order or in parallel with the order illustrated in the flow diagrams or sequence diagrams. Also, some steps in the operation may be omitted and additional steps may be added to the process. Further, the operation sequences (and operation flows) in the above-described embodiments may be implemented independently, or two or more operation sequences (and operation flows) may be combined and implemented. For example, some steps of one operation flow may be added to another operation flow, or some steps of one operation flow may be replaced with some steps of another operation flow.

In the above-described embodiment, the mobile communication system 1 based on NR has been described as an example. However, the mobile communication system 1 is not limited to this example. The mobile communication system 1 may be a TS-compliant system of either LTE (Long Term Evolution) or another generation system (for example, 6th generation) of the 3GPP standards. The base station 200 may be an eNB that provides Evolved Universal Terrestrial Radio Access (E-UTRA) user plane and control plane protocol termination towards the UE 100 in LTE. The mobile communication system 1 may be a system conforming to a TS of a standard other than the 3GPP standard. The base station 200 may be an IAB (Integrated Access and Backhaul) donor or an IAB node.

A program that causes a computer to execute each process performed by the UE 100 or the base station 200 may be provided. The program may be recorded on a computer readable medium. A computer readable medium allows the installation of the program on the computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, but may be, for example, a recording medium such as CD-ROM or DVD-ROM. Also, circuits that execute each process performed by the UE 100 or the base station 200 may be integrated, and at least a part of the UE 100 or the base station 200 may be configured as a semiconductor integrated circuit (chipset, SoC).

In the above embodiments, "transmit" may mean performing at least one layer of processing in the protocol stack used for transmission, or physically transmitting the signal wirelessly or by wire. It may mean sending to Alternatively, "transmitting" may mean a combination of performing the at least one layer of processing and physically transmitting the signal wirelessly or by wire. Similarly, "receive" may mean performing processing of at least one layer in the protocol stack used for reception, or physically receiving a signal wirelessly or by wire. may mean that Alternatively, "receiving" may mean a combination of performing the at least one layer of processing and physically receiving the signal wirelessly or by wire. Similarly, "obtain/acquire" may mean obtaining information among stored information, and may mean obtaining information among information received from other nodes. Alternatively, it may mean obtaining the information by generating the information. Similarly, "include" and "comprise" are not meant to include only the recited items, and may include only the recited items or in addition to the recited items. Means that it may contain further items. Similarly, in the present disclosure, "or" does not mean exclusive OR, but means logical OR.

Although the embodiments have been described in detail with reference to the drawings, the specific configuration is not limited to the above, and various design changes can be made without departing from the scope of the invention.

Although the present disclosure has been described with reference to examples, it is understood that the present disclosure is not limited to those examples or structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and configurations, as well as other combinations and configurations, including single elements, more, or less, are within the scope and spirit of this disclosure.

(Appendix)
Features of the above-described embodiment will be added.

(Appendix 1)
The first cell (C1) and the second cell (C2) belonging to the same frequency as the serving cell (C1) and the first cell (C1) are managed by the base station (200) that manages the first cell (C1) and the second cell ( A communication device (100) in which C2) is set,
a receiving unit (112) for receiving group information indicating whether the first cell (C1) and the second cell (C2) belong to the same timing advance group from the base station (200);
A communication device (100), comprising: a control section (120) that adjusts transmission timing of an uplink signal to the second cell (C2) based on the group information.

(Appendix 2)
The receiving unit (112) receives from the base station (200) a first timing advance for adjusting the transmission timing of the uplink signal to the first cell (C1),
When the group information indicates that the first cell (C1) and the second cell (C2) belong to the same timing advance group, the control unit (120) uses the first timing advance to perform the The communication device (100) according to appendix 1, wherein the transmission timing of the uplink signal to the second cell (C2) is adjusted.

(Appendix 3)
When the group information indicates that the first cell (C1) and the second cell (C2) belong to the same timing advance group, the control unit (120) controls the downlink from the first cell (C1). The communication device (100) of claim 2, wherein link timing is used as a timing reference for uplink transmissions to adjust transmission timing of uplink signals to said second cell (C2).

(Appendix 4)
The receiving unit (112) adjusts a first timing advance for adjusting the transmission timing of the uplink signal to the first cell (C1) and the transmission timing of the uplink signal to the second cell (C2). a second timing advance to adjust from the base station (200);
When the group information indicates that the first cell (C1) and the second cell (C2) belong to different timing advance groups, the control unit (120) uses the second timing advance to 4. The communication device (100) according to any one of appendices 1 to 3, wherein the transmission timing of an uplink signal to the second cell (C2) is adjusted.

(Appendix 5)
When the group information indicates that the first cell (C1) and the second cell (C2) belong to different timing advance groups, the control unit (120) controls the downlink from the second cell (C2). 5. The communication device (100) of claim 4, wherein link timing is used as a timing reference for uplink transmissions to adjust transmission timing of uplink signals to said second cell (C2).

(Appendix 6)
When the group information indicates that the first cell (C1) and the second cell (C2) belong to different timing advance groups, the control unit (120)
The receiving unit (112) receives a first medium access control (MAC) control element (CE) containing the first timing advance and a second MAC CE containing the second timing advance from the base station (200). receive and
The control unit (120)
managing a first timing advance value based on the first timing advance based on the first MAC CE;
The communication device (100) according to appendix 4 or 5, wherein a second timing advance value based on the second timing advance is managed independently of the first timing advance value based on the second MAC CE.

(Appendix 7)
The receiving unit (112) receives the first timing advance from the first cell (C1) and receives the second timing advance from the second cell (C2). communication device (100).

(Appendix 8)
The receiving unit (112) receives from the base station (200), together with the group information, beam measurement setting information for setting a beam measurement reference signal used for beam measurement for the second cell (C2). 8. A communication device (100) according to any of 7.

(Appendix 9)
A base station (200) that sets a first cell (C1) that is a serving cell and a second cell (C2) that belongs to the same frequency as the first cell (C1) in a communication device (100),
a control unit (230) for determining whether the first cell (C1) and the second cell (C2) belong to the same timing advance group;
a transmitter (211) configured to transmit group information indicating whether the first cell (C1) and the second cell (C2) belong to the same timing advance group to the communication device (100); Base station (200).

(Appendix 10)
The first cell (C1) and the second cell (C2) belonging to the same frequency as the serving cell (C1) and the first cell (C1) are managed by the base station (200) that manages the first cell (C1) and the second cell ( A communication method executed by a communication device (100) in which C2) is set,
receiving group information from the base station (200) indicating whether the first cell (C1) and the second cell (C2) belong to the same timing advance group;
adjusting transmission timing of uplink signals to the second cell (C2) based on the group information. A communication method.

Claims (7)

1. A communication device (100) in which a first cell (C1) and a second cell (C2) are set by a base station (200),
   a receiving unit (112) for receiving a timing advance group identifier corresponding to the first cell (C1) and a timing advance group identifier corresponding to the second cell (C2) from the base station (200);
   When receiving the timing advance group identifier corresponding to the first cell (C1) and the timing advance group identifier corresponding to the second cell (C2), the first transmission timing of the uplink signal and the uplink A communication device (100), comprising: a control section (120) that adjusts a second transmission timing of a signal.
2. The receiving unit (112) receives a first timing advance for adjusting the first transmission timing from the base station (200),
   The communication device (100) according to claim 1, wherein the control section (120) adjusts the second transmission timing using the first timing advance.
3. The communication device (100) according to claim 2, wherein the control unit (120) adjusts the second transmission timing using the downlink timing from the first cell (C1) as a timing reference for uplink transmission. .
4. The receiving unit (112) receives a first timing advance for adjusting the first transmission timing and a second timing advance for adjusting the second transmission timing from the base station (200). receiving, wherein the control unit (120) adjusts the first transmission timing using the first timing advance and adjusts the second transmission timing using the second timing advance; A communication device (100) as described.
5. The communication device (100) according to claim 4, wherein the control unit (120) adjusts the second transmission timing using the downlink timing from the second cell (C2) as a timing reference for uplink transmission. .
6. A base station (200) that sets a first cell (C1) and a second cell (C2) in a communication device (100),
   a transmitter (211) configured to transmit a timing advance group identifier corresponding to the first cell (C1) and a timing advance group identifier corresponding to the second cell (C2) to the communication device (100);
   When transmitting the timing advance group identifier corresponding to the first cell (C1) and the timing advance group identifier corresponding to the second cell (C2), the first transmission timing of the uplink signal and the uplink A base station (200), comprising: a controller (120) that controls a second transmission timing of a signal.
7. A communication method executed by a communication device (100) in which a first cell (C1) and a second cell (C2) are set by a base station (200),
   receiving a timing advance group identifier corresponding to said first cell (C1) and a timing advance group identifier corresponding to said second cell (C2) from said base station (200);
   When receiving the timing advance group identifier corresponding to the first cell (C1) and the timing advance group identifier corresponding to the second cell (C2), the first transmission timing of the uplink signal and the uplink and adjusting a second transmission timing of the signal.

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