KR101882102B1 - Methods for mobility control of a UE communicating V2X and Apparatuses thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling mobility of a mobile station (V2X) based on a mobile communication network, and more particularly, And more particularly, In particular, an embodiment provides a handover method for a terminal that performs a vehicle to everything (V2X), comprising: receiving and configuring synchronization type information for vehicle communication from a source base station; Receiving handover command information including resource configuration information for communication from a source base station and performing vehicle communication until completion of handover to a target base station using resource configuration information .

Description

[0001] The present invention relates to a method and apparatus for controlling a mobility of a UE performing V2X communication,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling mobility of a mobile station (V2X) based on a mobile communication network, and more particularly, And more particularly,

Rapid exchange of information based on communication technology is changing service, technology and life in various ways. In this situation, technology related to vehicle communication is also changing. For example, with the development of intelligent transportation systems, the development of vehicle communication technology and the development of intelligent automobile technology are rapidly taking place.

Particularly, with the development of vehicle communication, technologies for providing various services ranging from real-time traffic information on vehicles to warning for improving vehicle safety, a message for facilitating traffic flow, and cooperation using vehicle communication are further advanced.

Vehicle to everything (V2X), which symbolizes the evolution of vehicular communications, is the communication technology between vehicles and all interfaces. The form of V2X includes vehicle to vehicle (V2V), vehicle to infrastructure (V2I), vehicle to pedestrian (V2P), and is developed with the objective of increasing the safety of operation using vehicle communication, .

Wireless communication resources are required for smooth vehicle communication and wireless communication protocols for vehicle communication are also needed. Particularly, commercialization is carried out in many countries, and interest in vehicle communication using a mobile communication technology in which a communication network is established in a large area is increasing.

However, in the case of vehicle communication, basically high-speed mobility should be assumed, and vehicle communication should be smoothly performed even when the mobile communication terminal is out of base station coverage. In order to do this, it is an important task to allow stable vehicle communication to be maintained in consideration of a handover procedure that can be frequently generated according to high-speed movement. That is, it is necessary to develop a technology that satisfies the vehicle communication requirements even in a handover operation frequently occurring in a high-speed mobile situation by preventing or minimizing the communication disconnection temporarily in the handover procedure of the terminal.

One embodiment disclosed in the above background is to provide a method and apparatus capable of stably supporting vehicle communication even in a high-speed mobile communication based on mobile communication technology (for example, LTE or LTE-Advanced).

In addition, one embodiment of the present invention is to provide a concrete handover procedure for preventing or minimizing communication interruption in a handover process of a vehicle communication terminal.

According to an embodiment of the present invention, there is provided a handover method of a terminal for performing vehicle to everything (V2X), comprising: receiving and configuring synchronization type information for vehicle communication from a source base station; Receiving from the source base station handover command information including resource configuration information for vehicle communication set by the base station and performing the vehicle communication until completion of the handover to the target base station using the resource configuration information .

According to an embodiment of the present invention, there is provided a method of controlling handover of a terminal performing a vehicle to everything (V2X) by a source base station, comprising the steps of: determining a handover of a terminal performing a vehicle communication; Comprising: transmitting handover preparation information including at least one of configuration information of the terminal, global communication satellite configuration information of the terminal, and terminal capability information to the target base station; Receiving the configuration information, and transmitting the handover command information including the resource configuration information to the terminal.

In an exemplary embodiment of the present invention, a terminal performing vehicle to everything (V2X) includes a control unit configured to receive and configure synchronization type information for vehicle communication from a source base station, and a resource for vehicle communication set by the target base station And a receiving unit for receiving handover command information including configuration information from a source base station. The control unit provides a terminal device that performs vehicle communication until completion of handover to a target base station using resource configuration information.

One embodiment of the present invention is a source base station for controlling handover of a terminal that performs a vehicle to everything (V2X), comprising: a control unit for determining handover of a terminal performing vehicle communication; A transmission unit for transmitting handover preparation information including at least one of communication configuration information, Global Navigation Satellite System (GNSS) status information of a terminal, and terminal capability information to a target base station, and a resource configuration information And a transmitter for further transmitting handover command information including resource configuration information to the terminal.

The above-described embodiments provide smooth handover and seamless communication to a vehicle communication terminal having high mobility. Even when the base station coverage is exceeded, the vehicle communication can be continuously performed using the mobile communication technology Provides an effect.

1 is a diagram illustrating an example of a V2X communication scenario according to an exemplary embodiment.
2 is a diagram illustrating another example of a V2X communication scenario according to an embodiment.
3 is a diagram illustrating another example of a V2X communication scenario according to an embodiment.
4 is an exemplary diagram illustrating an E-UTRAN handover procedure.
5 is a diagram for explaining a terminal operation according to an embodiment.
6 is a view for explaining a source base station operation according to an embodiment.
7 is a diagram for explaining a terminal configuration according to an embodiment.
8 is a diagram for explaining a source base station configuration according to an embodiment.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Herein, the MTC terminal may mean a terminal supporting low cost (or low complexity) or a terminal supporting coverage enhancement. In this specification, the MTC terminal may mean a terminal supporting low cost (or low complexity) and coverage enhancement. Alternatively, the MTC terminal may refer to a terminal defined in a specific category for supporting low cost (or low complexity) and / or coverage enhancement.

In other words, the MTC terminal in this specification may mean a newly defined 3GPP Release-13 low cost (or low complexity) UE category / type for performing LTE-based MTC-related operations. Alternatively, the MTC terminal may support enhanced coverage over the existing LTE coverage or a UE category / type defined in the existing 3GPP Release-12 or lower that supports low power consumption, or a newly defined Release-13 low cost low complexity UE category / type.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data and the like. A wireless communication system includes a user equipment (UE) and a base station (BS, or eNB). The user terminal in this specification is a comprehensive concept of a terminal in wireless communication. It is a comprehensive concept which means a mobile station (MS), a user terminal (UT), an SS (User Equipment) (Subscriber Station), a wireless device, and the like.

A base station or a cell generally refers to a station that communicates with a user terminal and includes a Node-B, an evolved Node-B (eNB), a sector, a Site, a BTS A base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell.

That is, in the present specification, a base station or a cell has a comprehensive meaning indicating a part or function covered by BSC (Base Station Controller) in CDMA, Node-B in WCDMA, eNB in LTE or sector (site) And covers various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, RU, and small cell communication range.

Since the various cells listed above exist in the base station controlling each cell, the base station can be interpreted into two meanings. i) the device itself providing a megacell, macrocell, microcell, picocell, femtocell, small cell in relation to the wireless region, or ii) indicating the wireless region itself. i indicate to the base station all devices that are controlled by the same entity or that interact to configure the wireless region as a collaboration. An eNB, an RRH, an antenna, an RU, an LPN, a point, a transmission / reception point, a transmission point, a reception point, and the like are exemplary embodiments of a base station according to a configuration method of a radio area. ii) may indicate to the base station the wireless region itself that is to receive or transmit signals from the perspective of the user terminal or from a neighboring base station.

Therefore, a base station is collectively referred to as a base station, collectively referred to as a megacell, macrocell, microcell, picocell, femtocell, small cell, RRH, antenna, RU, low power node do.

Herein, the user terminal and the base station are used in a broad sense as the two transmitting and receiving subjects used to implement the technical or technical idea described in this specification, and are not limited by a specific term or word. The user terminal and the base station are used in a broad sense as two (uplink or downlink) transmitting and receiving subjects used to implement the technology or technical idea described in the present invention, and are not limited by a specific term or word. Here, an uplink (UL, or uplink) means a method of transmitting / receiving data to / from a base station by a user terminal, and a downlink (DL or downlink) .

There are no restrictions on multiple access schemes applied to wireless communication systems. Various multiple access schemes such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM- Can be used. An embodiment of the present invention can be applied to asynchronous wireless communication that evolves into LTE and LTE-Advanced via GSM, WCDMA, and HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000, and UMB. The present invention should not be construed as limited to or limited to a specific wireless communication field and should be construed as including all technical fields to which the idea of the present invention can be applied.

A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

In systems such as LTE and LTE-Advanced, the uplink and downlink are configured on the basis of one carrier or carrier pair to form a standard. The uplink and the downlink are divided into a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel, a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control Channel (EPDCCH) Transmits control information through the same control channel, and is configured with data channels such as PDSCH (Physical Downlink Shared CHannel) and PUSCH (Physical Uplink Shared CHannel), and transmits data.

On the other hand, control information can also be transmitted using EPDCCH (enhanced PDCCH or extended PDCCH).

In this specification, a cell refers to a component carrier having a coverage of a signal transmitted from a transmission point or a transmission point or transmission / reception point of a signal transmitted from a transmission / reception point, and a transmission / reception point itself .

The wireless communication system to which the embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-point transmission / reception system in which two or more transmission / reception points cooperatively transmit signals. antenna transmission system, or a cooperative multi-cell communication system. A CoMP system may include at least two multipoint transmit and receive points and terminals.

The multi-point transmission / reception point includes a base station or a macro cell (hereinafter referred to as 'eNB'), and at least one mobile station having a high transmission power or a low transmission power in a macro cell area, Lt; / RTI >

Hereinafter, a downlink refers to a communication or communication path from a multipoint transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiple transmission / reception point. In the downlink, a transmitter may be a part of a multipoint transmission / reception point, and a receiver may be a part of a terminal. In the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted / received through a channel such as PUCCH, PUSCH, PDCCH, EPDCCH, and PDSCH is expressed as 'PUCCH, PUSCH, PDCCH, EPDCCH and PDSCH are transmitted and received'.

In the following description, an indication that a PDCCH is transmitted or received or a signal is transmitted or received via a PDCCH may be used to mean transmitting or receiving an EPDCCH or transmitting or receiving a signal through an EPDCCH.

That is, the physical downlink control channel described below may mean a PDCCH, an EPDCCH, or a PDCCH and an EPDCCH.

Also, for convenience of description, EPDCCH, which is an embodiment of the present invention, may be applied to the portion described with PDCCH, and EPDCCH may be applied to the portion described with EPDCCH according to an embodiment of the present invention.

Meanwhile, the High Layer Signaling described below includes RRC signaling for transmitting RRC information including RRC parameters.

The eNB performs downlink transmission to the UEs. The eNB includes a physical downlink shared channel (PDSCH) as a main physical channel for unicast transmission, downlink control information such as scheduling required for reception of a PDSCH, A physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission in a Physical Uplink Shared Channel (PUSCH). Hereinafter, the transmission / reception of a signal through each channel will be described in a form in which the corresponding channel is transmitted / received.

The apparatus and method proposed in the present disclosure are applicable to a long-term evolution (LTE) mobile communication system, a long-term evolution-advanced (LTE-A) (HSDPA) mobile communication system, a high speed uplink packet access (HSUPA) mobile communication system, and a third generation partnership project 2 (3GPP2) A high rate packet data (HRPD) mobile communication system, a Wideband Code Division Multiple Access (WCDMA) mobile communication system of 3GPP2, a Code Division Multiple Access (3GPP2) CDMA) mobile communication system, an Institute of Electrical and Electronics Engineers (IEEE) 802.16m communication system, an Evolved Packet System: EPS), Mobile Internet Protocol (Mobile IP) system, and the like.

Although the following description is based on the V2X communication system, it is only for convenience of description, and is not limited to the contents and scope of rights of the V2X communication system of the present invention. Generally, The present invention can be applied to a field where communication technology is required. Furthermore, although the embodiments described herein may be separately described, various embodiments may be implemented integrally, unless the embodiments clearly contradict or contradict one another. In addition, the terminal described below may be an object capable of supporting object Internet or V2X communication, for example, an in-vehicle communication device, a smart phone, or the like. In this specification, an object supporting V2X communication will be described as "terminal", "V2X device", or "vehicle".

Meanwhile, the V2X communication in the present specification is meant to include both inter-terminal communication, inter-vehicle communication, and side link communication in which direct communication is performed between terminals via a mobile communication radio resource without going through a base station, . Therefore, in the following, side link communication, V2X communication, and inter-terminal communication are used in combination as needed.

1 is a diagram illustrating an example of a V2X communication scenario according to an exemplary embodiment. The description of each scenario in Fig. 1 is as follows.

- Scenario 1: The terminal is represented as a V2X carrier (V2X dedicated carrier / specific V2X carrier / V2X direct communication carrier / V2X carrier, hereinafter referred to as V2X carrier, , V2X direct communication carrier, V2X carrier of one of the V2X carriers).

- Scenario 2: The V2X carrier is granted to a single operator, and the terminal is within the coverage of a single operator for V2X communication.

- Scenario 3: V2X carrier is shared by multiple operators, and the terminal is within the operator's coverage for V2X communication.

- Scenario 4: when a V2X message is transmitted on a dedicated grant frequency managed by each operator and when it is received on all frequencies.

Since scenario 1 is out of coverage, the terminal can use autonomous resource selection for pre-configured resources. Since the scenario 2 is within the coverage, the UE can use the scheduled resource allocation or the autonomous resource selection according to the base station configuration.

2 is a diagram illustrating another example of a V2X communication scenario according to an embodiment. Cell 1 represents a cell using another carrier that is not a V2X carrier. Cell 2 represents a cell using a V2X carrier.

3 is a diagram illustrating another example of a V2X communication scenario according to an embodiment. Macro cell / macro cell base station / macro cell base station cell (Cell 1) uses another carrier other than the V2X carrier, and the small cells (Cell 2 and Cell 3) use the V2X carrier.

In the scenario described in FIGS. 1 to 3, the terminal performs V2X communication using a V2X carrier. For this, the terminal must be allocated a radio resource including a V2X carrier. That is, since V2X communication using mobile communication technology uses limited radio resources, it is necessary to allocate side link resources for V2X communication.

The following is a brief description of side link resource allocation.

Side link resource allocation

A terminal supporting side link communication can operate in two modes for resource allocation. For example, the UE can be divided into a resource allocation mode scheduled by the BS and a resource allocation mode selected autonomously.

Scheduled resource allocation has the following characteristics.

- The terminal needs to be in RRC_CONNECTED state to transmit data.

- The terminal requests the transmission resource to the base station. The base station schedules side link control information and transmission resources for transmission of data.

- The terminal sends a scheduling request (Downlink-Scheduling Request or random access) generated by the side link BSR (Buffer Status Report) to the base station. Based on the side link BSR, the BS can confirm that the MS has data for side link communication and estimate the resources required for the corresponding data transmission. The base station may schedule transmission resources for side-link communication using a configured side-link Radio Network Temporary Identifier (RNTI).

The autonomous resource selection of a terminal has the following characteristics.

- The terminal itself selects a specific resource among the resource pools. Then, side link control information and a transmission format for transmitting data can be selected.

- There can be up to eight transport pools provided by RRC signaling for pre-configured or in-coverage operation for out of coverage operation. Each pool may have ProSe Per-Packet Priority (PPPP) associated with one or more pools.

- If a resource pool is selected, the selection for that resource pool is valid for the SC period. After the side link control period ends, the terminal can again select resources from the resource pool.

When interested in the side link communication, the RRC CONNECTED terminal sends a side link terminal information message to the base station. In response to this, the base station can configure the side link RNTI in the terminal.

Whenever a terminal detects a cell on a public disaster, the terminal is considered to be in-coverage for Prose direct communication. The following rules apply to terminals:

- If the terminal is out of coverage, the terminal may use only autonomous resource selection.

- If the terminal is in coverage for side-link communication, it can use scheduled resource allocation or autonomous resource selection depending on the base station configuration. For example, the lower layer is configured to transmit the side link control information and corresponding data using the indicated resources in the resource pool.

- If the terminal is in coverage, it should only use the resource allocation mode indicated by the base station configuration, unless it is an exceptional case specified in the RRC (for example, in the exceptional case described in the 3GPP TS 36.331 document).

- Even if the terminal is configured to use scheduled resource allocation, if an exceptional case occurs, such as a radio link failure, the terminal may be allowed to temporarily use the terminal autonomous resource selection. In this exceptional case, the resource pool to be used may be provided by the base station.

A terminal that camped on or connected on one carrier frequency, but is interested in Prose direct communication on another carrier frequency, may look for a cell on a public disaster Prose carrier (hereinafter referred to as Prose carrier for ease of illustration) You should try.

An RRC_IDLE terminal that has camped on a cell on another carrier frequency but is within the coverage area of the E-UTRA cell on the Prose carrier may consider the Prose carrier as the highest priority. Then reselect the Prose carrier.

- An RRC_CONNECTED terminal serviced by a cell in another carrier frequency can send Prose direct communication indication information to the serving cell when it wants to perform Prose direct communication. The indication information includes information about the intended prose carrier.

- The serving cell indicates whether the UE allows SIB 18 (System Information Block 18) to send a Proxy UE information message.

- The serving cell may configure an inter-frequency RRM measurement on the Prose carrier.

When the terminal enters cell coverage on the Prose carrier, the base station performs inter-frequency mobility on the Prose carrier based on the measurement report.

If inter-frequency mobility is not performed by the serving cell, the terminal may perform side-link communication using the terminal autonomous resource selection from the pool of resources broadcast by the E-UTRA cell detected on the ProSe carrier have.

- If the terminal does not detect the E-UTRA cell on the Proce carrier, the terminal may use the pre-configured Public Disaster Prose resource for UICC or ME for Prose direct communication out of coverage.

- If the terminal detects an E-UTRA cell on the Proce carrier, the terminal stops using the pre-configured resources in the UICC or ME. The UE can perform side link communication using the UE autonomous resource selection from the resource pool broadcast by the E-UTRA cell detected on the ProSe carrier.

Hereinafter, V2X communication will be described as an example of side link communication.

V2X

By providing the vehicle with access to a mobile communication network (e.g., LTE or LTE-Advanced), the vehicle can be connected to the Internet and other vehicles. V2X (Vehicle to Everything) includes the following three types.

- Vehicle to Vehicle (V2V) Communication

- Vehicle to Infrastructure (V2I) Communication

- Vehicle to Pedestrian (V2P) Communication

In 3GPP Release-12, the D2D (Device to Device) technology has been standardized, and the basic environment for operating V2X communication based on LTE communication technology has been established. However, V2X has various use cases and requirements, and the way of applying LTE based V2X can be developed into various scenarios. Therefore, when applying V2X using conventional LTE technology, there may be a problem in detail.

As an example, in a conventional LTE technology, a side-link communication / discovery / synchronization resource configuration is applied for the frequency at which it is received or acquired. Moreover, for a terminal configured with one or more SCells (Secondary Cells), the side-link communication / discovery / synchronization resource configuration provided by dedicated signaling is applied to PCell (Primary Cell) or primary frequency.

If the RRC CONNECTED terminal performing direct communication on the ProSe carrier moves the cell, the UE performs handover. If the terminal performing the direct communication is instructed to use the scheduled resource allocation, the corresponding terminal can be directly suspended / delayed until the handover is completed.

V2X services can be applied to more terminals with higher mobility than Prose services. A large number of terminals that want to use a V2X carrier in a specific area may be located, and the hidden node problem due to mobility may occur more seriously. Therefore, in the case of the V2X service terminal, it is preferable to communicate through scheduling (e.g., dynamic or SPS (Semi-Persistent Scheduling) resource allocation compared to autonomous resource allocation. However, It may be difficult to perform the V2X transmission in accordance with the delay limit required for the V2X transmission. For example, it is difficult to satisfy a pre-crash sensing warning service having a strict delay requirement of 20 ms.

As described above, when the RRC CONNECTED terminal desires to perform the direct communication for the V2X service, there arises a problem that the direct communication for the V2X service is delayed / interrupted when performing the handover according to the conventional LTE handover procedure .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for controlling terminal handover in an LTE-based efficient V2X communication situation.

4 is an exemplary diagram illustrating an E-UTRAN handover procedure.

Referring to FIG. 4, in order to perform a handover procedure of a mobile station, a mobile station measures cell quality using measurement configuration information of a source base station, and transmits a measurement report including a measured result to a source base station. The source base station determines the handover of the terminal using the received measurement report.

In the handover preparation procedure, when the handover of the MS is determined, the source BS requests handover to the target BS, receives a handover request confirmation signal of the target BS, and transmits an RRC connection reconfiguration message including mobility control information to the MS do.

Through this, the UE initiates a handover procedure and enters a handover procedure. The terminal transmits data to the target base station through the source base station. The mobile station connects to the target base station that is the target of the handover, synchronizes, and establishes a connection for communication. When a connection with the target base station is established, the terminal transmits packet data to the target base station to perform communication.

In the handover completion procedure, the source base station is released through the path switch procedure between the target base station and the source base station and the core network entity, and the data packet path is switched to the target base station.

A detailed handover procedure is described in detail in the 3GPP TS 36.300 document, so that a description of the portions which do not obscure the features of the present invention will be omitted.

5 is a diagram for explaining a terminal operation according to an embodiment.

Referring to FIG. 5, a terminal performing a vehicle to everything (V2X) performs a step of receiving and configuring synchronization type information for vehicle communication from a source base station (S510).

For example, a terminal that intends to perform vehicle communication must identify a synchronization type for vehicle communication and configure the terminal. To this end, the terminal may receive synchronization type information for vehicle communication from a base station (e.g., a source base station). Then, the terminal configures the received synchronization type information in the terminal and can perform vehicle communication using the configured synchronization type information. The synchronization type information may indicate whether to use base station synchronization or GNSS based synchronization when the terminal performs vehicle communication. Or synchronization type information may include priority information for base station-based synchronization and GNSS-based synchronization. The synchronization type information is described in detail below again.

Meanwhile, the terminal performing the vehicle communication can receive the measurement configuration information used for the cell quality measurement and the like from the base station (the source base station in the handover procedure) constituting the RRC connection. The measurement configuration information may include a quality measurement result of a neighboring cell of the terminal and a quality measurement result of a cell to which the current terminal is connected. The terminal measures the channel quality for a plurality of cells using parameters included in the measurement configuration information, and transmits a measurement report including the measurement result to the source base station. The source base station can determine the handover of the terminal by checking the measurement report.

Thereafter, the UE performs step S520 of receiving, from the source base station, handover command information including resource configuration information for vehicle communication set by the target base station.

Based on the measurement report transmitted by the mobile station and the RRM information of the source base station, the source base station can determine whether the mobile station is handed over. If the handover of the terminal is determined, the terminal receives the handover command information from the source base station. For example, the handover command information may be transmitted through the RRC connection reconfiguration message and may be included in the mobility control information.

On the other hand, a terminal performing vehicle communication should prevent delay and interruption of data for vehicle communication in a handover process. To this end, the source base station may transmit the handover command information to the terminal including resource configuration information for vehicle communication set by the target base station. That is, in order to solve the problem of vehicle communication interruption or delay in the handover preparation procedure described with reference to FIG. 4, the source base station acquires information related to the vehicle communication radio resource to be used by the terminal from the target base station in the handover process, have. In addition, the resource configuration information may be set based on handover preparation information transmitted by the source base station to the target base station. The handover preparation information may include information on the vehicle communication configuration configured by the source base station, the Global Navigation Satellite System (GNSS) Information, and terminal capability information. The target base station can set the resource configuration information described above using the handover preparation information received from the source base station. For example, the vehicle communication configuration information included in the handover preparation information may include synchronization type information configured in the terminal by the source base station. The synchronization type information may be information for distinguishing whether the terminal uses base station synchronization or GNSS synchronization in performing vehicle communication.

Thereafter, the UE performs the step of performing the vehicle communication until completion of the handover to the target base station using the resource configuration information (S530).

For example, the UE can perform the vehicle communication using the resource configuration information acquired through the handover command information during the handover operation. The resource configuration information may include at least one of information on a radio resource for vehicle communication and synchronous configuration information. For example, the UE may establish synchronization for vehicle communication using base station synchronization, GNSS synchronization, or synchronous configuration information including priority of the base station and the GNSS. Also, with respect to radio resources for vehicle communication, the resource configuration information includes radio resource pool information for vehicle communication, information indicating radio resource allocation methods (e.g., scheduling by the base station or autonomous resource selection), etc. The UE can confirm the corresponding resource configuration information, configure a vehicle communication radio resource to be used until completion of the handover process, and perform vehicle communication using the radio resource as necessary.

As described above, the source base station transmits the handover command information including resource configuration information for vehicle communication to the terminal, so that the terminal can prevent the interruption and delay of the vehicle communication using the resource configuration information even before the handover is completed can do.

6 is a view for explaining a source base station operation according to an embodiment.

Referring to FIG. 6, the source base station may perform a step of determining a handover of a terminal performing vehicle communication in order to control a handover of a terminal performing a vehicle to everything (V2X) ( S610). For example, the source base station can determine whether to hand over the UE using at least one of the measurement report received from the UE and the RRM information of the source base station. Here, the terminal may mean a terminal performing vehicle communication, and the source base station means a base station that forms an RRC connection with a terminal performing vehicle communication. The source base station can provide PCell to the terminal. The source base station can determine and configure the synchronization type information for vehicle communication with the corresponding terminal for vehicle communication of the corresponding terminal before the handover decision for the terminal.

The source base station can perform handover preparation information including at least one of the vehicle communication configuration information configured by the source base station, the Global Navigation Satellite System (GNSS) status information of the terminal, and the terminal capability information to the target base station (S620). The source base station can transmit at least one of the configuration information related to the vehicle communication, the GNSS status information of the terminal, and the capability information of the terminal, which the source base station has configured to the terminal, to the target base station that is the target of the handover. The information transmitted to the target base station may be included in the handover request message.

For example, the vehicle communication configuration information may include synchronization type information configured in the terminal. The synchronization type information may include information indicating whether the corresponding terminal is a type using base station based synchronization or a type using GNSS based synchronization. That is, the vehicle communication configuration information includes information indicating which type of synchronization is configured or used by the terminal. The handover preparation information includes the AS- config of the handover request message Field.

The GNSS status information may be included in the handover preparation information and transmitted to the target BS when the MS receives the information related to the GNSS reception status of the MS from the MS. On the other hand, for example, the terminal capability information may include information on the capability of the terminal, such as whether the terminal can use a GNSS-based synchronization source, what synchronization configuration the terminal can support, and the like.

The source base station may perform the step of receiving the resource configuration information for the vehicle communication of the terminal from the target base station (S630). The target base station generates resource configuration information that can be used by the mobile station before the handover is completed using the handover preparation information received from the source base station and transmits the generated resource configuration information to the source base station. The resource configuration information is set by the target base station and is used to prevent delay and interruption of data transmission / reception that may occur during the handover process.

For example, the resource configuration information may include information indicating a vehicle communication radio resource to be used by the terminal before the handover of the terminal is completed. As another example, the resource configuration information may include synchronization configuration information to be configured by the UE until completion of handover of the terminal. As another example, the resource configuration information may include both the information indicating the radio resource and the synchronization configuration information.

The source base station may perform a step of transmitting handover command information including resource configuration information to the terminal (S640). The source base station may transmit the resource configuration information received from the target base station to the terminal by including it in the handover command information. The handover command information is included in the RRC connection reconfiguration message and can be delivered to the terminal. The terminal receives the handover command information and performs a preparation procedure for handover.

The terminal can maintain the vehicle communication based on the resource configuration information until the handover is completed or before synchronization is established with the target base station or until data is transmitted / received through the target base station.

Through this, the terminal can prevent the delay or interruption of the vehicle communication that may occur during the handover process, thereby securing the low delay and high reliability requirements required in the vehicle communication.

Hereinafter, the operation of the terminal and the base station described with reference to FIGS. 5 and 6 will be described in more detail, and the information included in the handover preparation information and the handover command information will be described in more detail. For convenience of explanation, the above-described vehicle communication can be described as V2X operation, side link direct communication, and the like as necessary, for convenience of explanation.

As shown in step 3 of FIG. 4, the source base station determines the handover based on the measurement report and the RRM information. Prior to step 3, the terminal can perform V2X communication. Or at this time, for example, the terminal can perform direct communication based on source base station synchronization. In another example, the terminal may perform direct communication based on the GNSS (or a GNSS-equivalent synchronization source, GPS, GLONASS, BDS, GALILEO, etc., hereinafter referred to as GNSS for ease of description) synchronization. To this end, the base station may transmit synchronization type information for indicating a synchronization type to the terminal. The terminal may perform vehicle communication using the synchronization type information indicated by the base station.

The base station may instruct the terminal to configure synchronization for V5X based on PC5 during base station based synchronization and GNSS synchronization. For example, when the terminal is in a carrier operated on a side link-based V2X, the base station may indicate a priority so that the terminal can select between base station-based synchronization or GNSS. In another example, the base station may allow the terminal to perform a V2X operation (e.g., vehicle communication) in accordance with GNSS synchronization. In another example, when a cell that is not a V2X carrier is connected as a serving cell (PCell) and performs a V2X operation using a V2X dedicated carrier (when the PC5 carrier and the Uu carrier are different), based on the GNSS synchronization timing V2X operation.

The source base station may send a handover request message to the target base station. The handover request message may include Prose authentication information. Or the handover request message may include V2X authentication information. The V2X authentication information indicates information indicating whether the terminal has authenticated the ProSe-based V2X service. The V2X authentication information indicates information received from the core network to the base station during the NAS signaling process.

The handover request message may include a handover preparation information message.

The handover preparation information may include one or more of the following pieces of information. That is, the handover preparation information may include at least one of vehicle communication configuration information including V2X synchronization configuration information, GNSS status information, and GNSS-related UE Capability. Hereinafter, each piece of information that the handover preparation information can include will be described in detail.

V2X  Synchronous configuration information

The handover preparation information described above may include the source vehicle communication configuration information and the vehicle communication configuration information may include the V2X synchronization configuration information set by the source base station and the vehicle.

The handover preparation information may include AS- config information. The AS- config included in the handover preparation information may include the source V2X communication configuration information. The AS-config included in the handover preparation information may include the source V2X discovery configuration information.

The AS- config included in the handover preparation information may include the source V2X synchronization configuration information. For example, if the source base station has configured the terminal to include information indicating that the terminal is to establish synchronization for the PC5-based V2X during base station-based synchronization and GNSS synchronization, the source base station can forward it to the target base station.

In the conventional LTE technology, terminals in coverage can acquire synchronization using a synchronization signal transmitted by a base station. Therefore, the side link operation can be performed between the terminals in the coverage according to the base station synchronization. In order to support the side link operation between terminals existing in different cells in a side link operation or an asynchronous network out of coverage, synchronization is performed through Sidelink Broadcast Control Channel (SBCCH) which provides side link synchronization signal and system and synchronization related information Respectively. Accordingly, in order to perform synchronization for a side link operation out of coverage, the UE can operate as a synchronization source for transmitting a synchronization signal with the SBCCH.

The synchronization configuration information included in the system information 18 (SIB 18) includes the following information.

In the conventional LTE technology, the side link synchronization configuration information ( SL - SyncConfig ) includes configuration information ( rxParamsNCell ) related to reception of the synchronization signal from the neighboring cell and configuration information For example, there was no need to pass information including the side link sync signal identifier (SLSSID), transmission parameters (txParameters), etc. to the target cell to identify the cell. However, if the UE performs the V2X operation using the GNSS synchronization configuration information, the target base station can use this information to indicate the synchronization configuration information of the handed-over UE. The target base station may need this information to minimize V2X service interruption after handover or to direct GNSS-based synchronization configuration.

The target base station may instruct the terminal to perform a V2X operation on a GNSS timing basis. Hereinafter, the V2X operation for synchronous information transmission will be described, but the same can be applied to the V2X direct communication / discovery / monitoring operation.

For example, the target base station may indicate whether the terminal should transmit synchronization information. That is, it can indicate whether the terminal can be a synchronous source. For this, the target base station can set the network control synchronization transmission information on the RRC reconfiguration message and instruct the terminal. If set to on value, it indicates that the terminal should transmit synchronization information. Whereas the off value indicates that the terminal does not transmit this information. When the network control synchronous transmission information is configured, the UE can transmit the synchronization signal based on the GNSS based synchronization when the GNSS is configured as the synchronization source according to the priority of the GNSS and the base station synchronization. This allows the synchronization signal to be transmitted based on the GNSS-based synchronization even before the handover is completed. This will be separately described later.

For example, a terminal capable of V2X operation or a terminal capable of transmitting a side-link synchronous signal can be used when transmitting a direct discovery announcement, when in coverage on a frequency used for side link discovery, , If it is in the RRC CONNECTED state, and if the network control sync transmission information is configured and set to the ON value, it can transmit the V2X sync signal.

As another example, a terminal capable of V2X operation or a terminal capable of transmitting a side link synchronous signal can transmit a direct discovery announcement (or perform V2X direct communication), if the frequency used for side link discovery V2X / side link dedicated frequency, if it is in GNSS coverage, if it is in RRC CONNECTED state, and if the network control sync transmission information is configured and set to on value, it can transmit the V2X sync signal .

As another example, a terminal capable of performing V2X operation or a terminal capable of transmitting a side-link synchronous signal can transmit a cell that is not a V2X carrier when transmitting a direct discovery announcement (or performing V2X direct communication) When performing a V2X operation using a V2X dedicated carrier, if it is in GNSS coverage, if it is in the RRC CONNECTED state, and if the network control sync transmission information is configured and set to the ON value, the V2X A synchronous signal can be transmitted.

As another example, a terminal capable of V2X operation or a terminal capable of transmitting a side link synchronous signal can transmit a cell on a V2X carrier to a serving cell (or a V2X carrier) when transmitting a direct Discovery Announcement (or performing V2X direct communication) PCell), if it is in GNSS coverage, and if the Network Controlled Synchronization Transmission Information is configured and set to the On value, the V2X Sync Signal can be transmitted.

As another example, a V2X directly communicatable terminal configured to transmit V2X direct communication by an upper layer, regardless of whether there is data to be transmitted, if it is in the RRC CONNECTED state and the network control sync transmission information is configured and set to the ON value V2X sync signal can be transmitted. For example, when a terminal is connected to a cell that is not a V2X carrier as a serving cell (PCell) and performs a V2X operation using a V2X dedicated carrier, the terminal may transmit a V2X synchronization signal based on a GNSS synchronization. Or, when the V2X carrier is used for V2X operation and the V2X carrier is used for the side link discovery, the terminal can transmit the V2X synchronization signal based on the GNSS synchronization.

As another example, a V2X directly communicatable terminal configured to transmit V2X direct communication by an upper layer, regardless of whether there is data to be transmitted, is in the RRC CONNECTED state, and the network control synchronous transmission information is not configured, If the RSRP measurement value of the selected cell for direct communication / discovery announcement transmission is lower than the coverage synchronization transmission threshold, the V2X synchronization signal can be transmitted if the GNSS network control synchronization transmission information is set to the ON value.

The base station may indicate whether the terminal should transmit GNSS-based synchronization information. That is, it can indicate whether the terminal can be a synchronous source. For this purpose, the base station can set the GNSS-based control synchronization transmission information on the RRC reconfiguration message and instruct the terminal. The GNSS-based control synchronization transmission information may indicate an information element that is distinguished from the network control synchronization transmission information. If set to on, it indicates that the terminal should transmit GNSS-based synchronization information. On the other hand, the off value indicates that the terminal does not transmit such information. When the GNSS-based control-synchronous transmission information is configured, the UE can transmit a synchronization signal based on the related GNSS-based synchronization.

The information that the source base station conveys to the target base station may include GNSS synchronization related information. As an example, it may include configuration information for instructing the terminal to use the GNSS as a synchronization source. As another example, the terminal may include information for instructing the terminal to configure the synchronization for the PC5-based V2X during base station-based synchronization and GNSS synchronization. For example, information indicating priority in base station based synchronization or GNSS based synchronization. Another example may include V2X sync configuration information.

The target base station may include configuration information for GNSS reception and instructing the terminal to use the GNSS as a synchronization source. The GNSS synchronous configuration information includes GNSS sync identification information, a GNSS synchronization window, a threshold value for using GNSS synchronization, information / base station timing for indicating the timing offset value to be used as a synchronization source by the UE in the Coordinated Universal Time information, When using the information indicating the transmission timing of the GNSS synchronous terminal considering the distance between the base station and the terminal, the base station position information, and the GNSS synchronization, the difference between the timing offset of the manganese / GNSS synchronization offset / GNSS-system frame number (subframe) CP length and GNSS synchronous transmission threshold value of the mobile station.

For example, the BS may transmit GNSS synchronization related information to the MS periodically / intermittently / at the request of the MS. Accordingly, even if the UE does not directly receive the GNSS, the UE can receive the GNSS synchronization related information periodically / intermittently / at the request of the UE, so that the UE can operate as a synchronous source using the reliable GNSS synchronization. The base station can configure the terminal with the indication information for configuring this operation through the RRC reconfiguration message.

As another example, a terminal capable of V2X operation or a terminal capable of transmitting a side-link synchronous signal may transmit a direct discovery announcement, when in coverage on a frequency used for side link discovery, When in coverage, it can send a GNSS-based V2X sync signal if in the RRC CONNECTED state and if the GNSS-based control sync transmission information is configured and set to the ON value.

As another example, a terminal capable of V2X operation or a terminal capable of transmitting a side-link synchronous signal can transmit a direct discovery announcement, when it is in coverage on a frequency used for side link discovery, When in GNSS coverage, it can transmit a GNSS-based V2X sync signal if in the RRC CONNECTED state and if the GNSS-based control sync transmission information is configured and set to the ON value.

As another example, the UE can be configured to operate as a synchronous source only when the UE can reliably receive GNSS or when reliable GNSS synchronization is obtained even if the UE is set to the ON state when transmitting synchronization information based on the GNSS. And the crisis base station can configure a condition for this.

The base station can instruct the terminal to select one of the base station-based synchronization and the GNSS synchronization. Alternatively, the base station may indicate a priority for base station-based synchronization or GNSS synchronization when the terminal is in a carrier operated on a side-link-based V2X. Alternatively, the base station may instruct the terminal to synchronize based on the GNSS to perform the V2X operation.

The base station may indicate the GNSS synchronous transfer threshold to the terminal. The GNSS Sync Transfer Threshold indicates the threshold used while in the GNSS coverage area. If the UE is greater than the GNSS synchronous transmission threshold value (eg, a measurement value of a certain GNSS reception state such as a GNSS reception signal strength / quality / intensity / interference) V2X synchronization signal / side link synchronization signal can be transmitted by the base station instruction information. The base station can configure the terminal with the indication information.

For example, when a UE capable of V2X operation or a side link capable of transmitting a synchronous signal transmits a direct Discovery announcement, if the network control synchronization transmission information is not configured, Information or a GNSS synchronous transmission indication from the base station and the GNSS reception status measurement is greater than the GNSS synchronous transmission threshold.

As another example, a V2X directly communicatable terminal configured to transmit V2X direct communication by an upper layer, if it is in the RRC CONNECTED state, regardless of whether there is data to be transmitted, if the network control synchronization transmission information is not configured, Based GNSS synchronous transmission indication information from the base station and a GNSS-based V2X synchronous signal if the measured GNSS reception status is greater than the GNSS synchronous transmission threshold value.

As another example, if the GNSS measurement is not better than the GNSS synchronous transfer threshold, the base station may cause the V2X sync signal to be transmitted using the indicated in-coverage sync transfer threshold. The in-coverage synchronous transfer threshold indicates the threshold used during coverage in V2X. The terminal can transmit the base station synchronization-based V2X synchronization signal / sidelink synchronization signal when the RSRP measurement value of the selected cell for the V2X direct communication / discovery announcement transmission is higher than the coverage synchronization transmission threshold.

In another example, when the terminal is lower than the coverage synchronization transmission threshold of the selected cell for the V2X direct communication / discovery announcement transmission, and the measured GNSS value is greater than the GNSS synchronous transmission threshold, the terminal transmits the GNSS-based V2X Synchronous signal / side link synchronous signal.

As another example, when a terminal capable of V2X operation or a terminal capable of transmitting a side link synchronization signal transmits a direct discovery announcement, if the network control synchronization transmission information is configured and set to the ON value, the GNSS measurement value If it is better than the GNSS synchronous transfer threshold, it can send a GNSS-based V2X sync signal.

As another example, a terminal capable of V2X operation or a terminal capable of transmitting a side-link synchronous signal can transmit a direct discovery announcement, when in coverage on a frequency used for side link discovery, If it is better than the GNSS Sync Transmission Threshold, it can send a GNSS-based V2X sync signal if it is in the RRC CONNECTED state and if the network control sync transmission information is configured and set to the ON value.

The base station may configure additional information to prevent GNSS synchronization selection when directing the terminal to the GNSS Sync Transmission Threshold value. For example, at least one of minimum hysteresis or maximum hysteresis, scaling factor, duration / time.

Even if GNSS reception quality is lower than a certain threshold, even if GNSS reception is difficult, the UE maintains its own GNSS synchronization for a certain period of time and can perform V2X operation based on it. Even if the UE temporarily fails to receive the GNSS, the timer may be operated to maintain the GNSS reception quality even if the quality of the GNSS reception is lower than a predetermined threshold value to prevent immediate synchronous switching. This timer may be preconfigured or may be indicated by the base station. If the GNSS receive quality exceeds the threshold and meets GNSS synchronization while this timer is running, this timer can be stopped or restarted.

Terminal GNSS  Status information

There is no need to transmit the side link synchronous configuration information to the target cell since the conventional LTE technology is synchronized with base station synchronization or preconfigured timing. However, if the terminal performs the V2X operation using the GNSS synchronization configuration information, the target base station can use this information to indicate the synchronization configuration information of the handed-over terminal. However, when the terminal is configured to perform a V2X operation (or a V2X operation based on the PC5 via GNSS synchronization by the base station instruction) based on the synchronization source timing by the base station instruction, the terminal configures the synchronization via the GNSS You can not succeed in something. For example, a user may manually disable GPS hardware, the GPS hardware may not be operational, or the terminal may not be GNSS-synchronized for any reason, such as low GNSS quality (when out of GNSS coverage for some time) .

If the source base station receives the GNSS status information of the terminal from the terminal and thus knows the source base station, the source base station transmits this information to the target base station so that the target base station can minimize the V2X service interruption after the handover or instruct the GNSS- It can be used to construct information. The target base station can indicate the configuration information about the V2X synchronization source configuration of the target base station or the V2X synchronization information transmission based on the information received from the source base station.

The terminal can inform E-UTRAN about GNSS status for V2X communication via PC5 (GNSS based). For example, when the terminal is interested in V2X transmission / reception (using a GNSS-based side link) or is no longer interested in V2X transmission / reception, or when the GNSS receivable status changes, When the radio reception state is better than the specific threshold value indicated by the base station, or when the GNSS radio reception state becomes worse than the specific threshold value indicated by the base station, or when the base station requests to report the GNSS reception information / GNSS reception related information to the base station , The RRC CONNECTED terminal (or the terminal on which V2X is configured) may initiate a GNSS status reporting procedure.

For example, the UE can set the contents of a message to be transmitted to the BS (denoted as a GNSS status report message below for convenience of description) as follows. For example, the terminal sets the GNSS receivable status variable to the GNSS receivable status. For example, the terminal sets GNSS reception measurements on GNSS measurement variables. For example, the terminal includes GNSS reception information in the GNSS status report message.

The terminal submits a GNSS status report message to the lower layer for transmission.

The terminal can report to the base station if GNSS reception is not possible.

For example, if the UE determines that one or more of the GNSS received signal strength, GNSS received signal strength, GNSS received signal quality, GNSS received SNR, UE GNSS timing, (E.g., any measurement value for determining the state) is bad (e.g., lower than the threshold configured by the base station), a timer (configured by the base station) .

When the timer expires, the terminal may set the GNSS receivable state variable to the receivable state and send a GNSS status report message to the base station.

When the above-described start timer is in operation and the GNSS reception measurement value is improved (exceeds the above-mentioned threshold value or the base station exceeds the above-described threshold value for a specified time period), the terminal transmits the above- You can stop.

As another example, the terminal can perform the above-described GNSS status reporting through a side link terminal information message.

The terminal may initiate a side-link terminal information message to report parameters for the GNSS-based side-link operation.

If the terminal is configured to report parameters for a GNSS-based side-link operation (e.g., a GNSS-based PC5 V2X communication / discovery / synchronization resource configuration / service) (and / , The terminal can initiate a side link terminal information message.

As another example, the terminal may perform the above-described GNSS status reporting through a terminal information message (or any uplink RRC message).

The terminal may initiate a side-link terminal information message to report parameters for the GNSS-based side-link operation.

If the terminal is configured to report parameters for a GNSS-based side-link operation (e.g., a PC5 V2X communication / discovery / synchronization resource configuration / service based on GNSS synchronization) (and / or a terminal supports GNSS- , The terminal can initiate the terminal information message.

The target base station may indicate whether the terminal should transmit synchronization information. That is, whether the terminal can be a synchronous source. To this end, the base station may set the network control synchronization transmission information on the RRC reconfiguration message and instruct the terminal. If set to on value, it indicates that the terminal should transmit synchronization information. Whereas the off value indicates that the terminal does not transmit this information. When the network control synchronization transmission information is configured, the mobile station can transmit the synchronization signal based on the related base station synchronization (PSS / SSS).

For example, a terminal capable of V2X operation, or a terminal capable of transmitting a side-link synchronous signal, transmits a direct discovery announcement, when in coverage on a frequency used for side link discovery, , If it is in the RRC CONNECTED state, and if the network control sync transmission information is configured and set to the ON value, the V2X sync signal can be transmitted.

When the base station instructs it to perform V2X operations using GNSS synchronization (or when the base station instructs GNSS synchronization to perform V2X operations prior to base station synchronization), the terminal may transmit a GNSS synchronous V2X synchronization signal have.

For example, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE may suspend / suspend transmission of the V2X sync signal based on the GNSS synchronization.

As another example, if the UE fails to synchronize with the GNSS due to any one of the reasons described above or any of the reasons described above, the UE can transmit the base station synchronization based V2X synchronization signal.

As another example, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE can transmit the V2X synchronization signal based on the base station synchronization by the base station indication. The base station can configure the terminal with the indication information.

A V2X directly communicatable terminal configured to transmit V2X direct communication by an upper layer, regardless of whether there is data to transmit, if it is in the RRC CONNECTED state and if the network control sync transmission information is configured and set to the ON value, Lt; / RTI >

For example, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE may suspend / suspend transmission of the V2X sync signal based on the GNSS synchronization.

As another example, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE can transmit the V2X synchronization signal based on the base station synchronization.

As another example, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE can transmit the V2X synchronization signal based on the base station synchronization by the base station indication. The base station can configure the terminal with the indication information.

A V2X directly communicatable terminal configured to transmit V2X direct communication by an upper layer, regardless of whether there is data to be transmitted, if it is in the RRC CONNECTED state, and the network control synchronous transmission information is not configured and the terminal transmits V2X direct communication / If the RSRP measurement of the selected cell for announcement transmission is less than the in-sync transmission threshold, then a V2X sync signal can be sent if GNSS-based synchronous transmission is indicated.

For example, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE may suspend / suspend transmission of the V2X sync signal based on the GNSS synchronization.

As another example, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE can transmit the V2X synchronization signal based on the base station synchronization.

As another example, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE can transmit the V2X synchronization signal based on the base station synchronization by the base station indication. The base station can configure the terminal with the indication information.

GNSS  relation UE  About Capability

The UE can transmit a UE capability message including the GNSS capability information to the base station (or the base station via the core network or the core network).

The terminal capability transmission procedure on the RRC is for transmitting the terminal radio access capability information from the terminal to the base station.

The base station initiates this procedure to the RRC CONNECTED terminal when the base station needs (additional) terminal radio access capability information.

Upon receiving the UE capability inquiry message from the base station, the UE can transmit a UE capability information message including the terminal capability information to the base station.

The base station can configure the terminal to use the GNSS as a synchronization source using the terminal capability information indicating whether the GNSS can be used as the synchronization source.

One example of terminal capability information indicating whether GNSS can be used as a synchronization source is a parameter indicating whether the terminal has a GNSS receiver that can be used in the RRC measurement report and to provide detailed location information in the measurements logged in the RRC_IDLE -Location) can be used. For example, the base station can determine whether to configure the terminal to use the GNSS as a synchronization source based on the parameter information.

As another example, you can define a new parameter that is distinct from the above parameters to indicate that you can configure the synchronization source. Since the terminal performs the PC5-based V2X communication / service using the GNSS as the synchronization source, it is a function different from the conventional location information providing method, so that a new parameter can be defined and configured. Based on this information, the base station can determine whether to configure the terminal to use the GNSS as a synchronization source.

In another example, the source base station may transmit the GNSS-related capability information of the terminal to the target base station. The target base station can indicate the configuration information about the V2X synchronization source configuration of the target base station or the V2X synchronization information transmission based on the information received by the source base station.

The terminal that receives the instruction information from the target base station to configure the GNSS to use as the synchronization source can perform the V2X operation using the GNSS as the synchronization source.

For example, the UE may monitor the selected reference reference terminal ( SyncRefUE ) according to the timing of the synchronization reference terminal when the GNSS is used as a synchronization source. Or if the terminal does not have a selected synchronization reference terminal, based on its own timing of the GNSS reception base of the terminal. Alternatively, the terminal may monitor based on the GNSS synchronization timing configured by the base station indication.

In another example, if the selected synchronization reference terminal (SyncRefUE) uses the GNSS as the synchronization source, the terminal may transmit the V2X control information and the corresponding data according to the timing of the synchronization reference terminal. Or if the terminal does not have a selected synchronization reference terminal, it can transmit the V2X control information and corresponding data based on the own timing of the GNSS reception base of the terminal. Alternatively, the terminal can transmit the V2X control information and the corresponding data based on the GNSS synchronization timing configured by the base station instruction.

For example, if the terminal fails to synchronize with the GNSS due to one of the reasons described above or for any of the reasons described above, the terminal may suspend / suspend transmission of V2X control information based on its own timing based on the GNSS synchronization and corresponding data, or V2X monitoring .

Alternatively, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE can perform V2X monitoring and transmission of the V2X control information based on the base station synchronization based on its own timing.

Alternatively, if the UE fails to synchronize with the GNSS due to one of the reasons described above or any of the reasons described above, the UE may transmit or V2X monitor the V2X control information based on its own timing by the base station indication and the corresponding data. The base station can configure the terminal with the indication information.

In another example, the terminal can transmit or V2X monitor the V2X control information based on its own preconfigured timing. The base station may configure the terminal with indication information for this purpose or this information may be pre-configured in the terminal.

The handover preparation information may further include at least one of help information for determining and designating the SPS configuration as needed, or configuration information for instructing cross-carrier scheduling and assistance information for the SPS interval, in addition to the above-described information.

The target base station may use the handover preparation information to set resource configuration information for preventing data interruption and delay in the handover process of the terminal and transmit the resource configuration information to the terminal through the source base station.

Hereinafter, the operation of the terminal will be described when the source base station transmits the resource configuration information constituted by the target base station to the terminal including the handover command information.

Handover  The operation of the terminal that has received the command information

Hereinafter, the operation of the terminal that has received the handover command will be described.

Upon receiving the RRC Connection reconfiguration message indicating the handover or the mobility control information (Mobilitycontrolinfo) or receiving the RRC Connection reconfiguration message, the UE performs the terminal operation through the included information and transmits the RRC Connection reconfiguration completion message Can perform the following operations.

The terminal starts by setting the timer value of the timer T304 to t304 included in the mobility control information.

For example, if the handover command information includes instruction information for configuring synchronization for V5 communication based on GN 5 based on GNSS synchronization, the terminal can start GNSS-based synchronization. Alternatively, the UE may start GNSS-based synchronization by acquiring synchronization-related information from the GNSS when information indicating the priority of the GNSS synchronization is included in the handover command information, or when the terminal includes the GNSS synchronization configuration information.

As another example, when the handover command information includes the instruction information for configuring the synchronization for the PC5-based V2X communication based on the GNSS synchronization, or when the information indicating the priority of the GNSS synchronization is included, If included, the terminal may initiate GNSS synchronization without requiring acquisition of synchronization related information from the GNSS in the case of receiving the GNSS synchronization information.

As another example, the terminal may acquire GNSS synchronization related information of the target PCell and start synchronization with the GNSS if any information is present. If necessary, the terminal may acquire synchronization related information from the GNSS and start synchronization with the GNSS.

As another example, if the UE receives the GNSS synchronization related system information broadcasted by the target PCell, the UE transmits the RRC reconfiguration message including the mobility control information during the last 1 second preceding reception of the RRC reconfiguration message the RRCConnectionReconfiguration message including mobilityControlInfo) may transmit a V2X MS information message including the GNSS status information message to the BS.

The UE can perform V2X operations based on GNSS synchronization until the handover is completed.

For example, the UE may perform a random access procedure prior to performing a random access procedure on the target cell or before receiving the RRC reconfiguration message and transmitting the random access preamble, or during performing the random access procedure, When the UE receives the GNSS directly from the base station, or when the UE receives the GNSS synchronization related information from the base station, or when the UE receives the GNSS-based information from the base station before completing the random access procedure or transmitting the RRC reconfiguration completion message, When information indicating synchronization information transmission is received, the GNSS can be used as a synchronization source. That is, the UE can perform synchronization information transmission based on the GNSS when the above conditions are satisfied, or can perform the GNSS-based V2X operation.

For example, if the handover command information includes the instruction information for configuring synchronization for the PC5-based V2X based on the GNSS synchronization, or if the information indicating the priority of the GNSS synchronization is included When the GNSS synchronous configuration information is included, the UE transmits a random access response message to the target cell before performing the random access procedure or before receiving the RRC reconfiguration message, transmitting the random access preamble, performing the random access procedure, Or when the UE receives the GNSS synchronization related information directly from the base station before the UE completes the random access procedure or transmits the RRC reconfiguration complete message, or when the UE receives the GNSS synchronization related information from the base station Can be used. That is, the UE can perform synchronization information transmission based on the GNSS when the above conditions are satisfied, or can perform the GNSS-based V2X operation.

In another example, if an RRC reconfiguration message including mobility control information is received and the corresponding timer (e.g., T304) is operating, the terminal may transmit resource allocation information (e.g., For example, the resource configuration information of FIG. 5 and FIG. 6) to perform the V2X operation. To this end, the terminal may receive resource allocation information for minimizing temporary interruption during handover by the source base station.

For example, the resource allocation information may be communication transfer exception pool information by the conventional Release 12 side link direct communication technology. The communication transmission exceptions pool used in the side link direct communication technology is used when receiving an RRC connection reconfiguration message including a physical layer problem or a radio link failure or a side link communication configuration in an RRC connection setup or receiving an RRC connection release or an RRC connection rejection Can be displayed.

As another example, the resource allocation information may be new communication transfer pool information that is distinguished from the communication transmission exception pool by the conventional Release 12 side link direct communication technology. The communication transfer exception pool used in the side link direct communication technology can perform communication based on the timing by the preconfigured pool. However, if the communication exception pool is based on the GNSS synchronization like the V2X operation, It is possible to newly designate and direct it. Specifically, when the terminal is in the RRC CONNECTED and the terminal uses PCell for V2X communication, the physical layer problem or radio link failure is configured to be transmitted using the resource pool indicated by the detected current PCell. Alternatively, if the UE is in the RRC CONNECTED and configured by setting the communication transmission resource to be scheduled by the base station via the PCell, it starts when starting the timer or the RRC reset procedure starting when detecting the physical layer problem in the PCell When the timer is operating and the PCell or base station (source base station or target base station) detecting the physical layer problem or radio link failure of the terminal broadcasts system information including the GNSS-based V2X communication transmission exception pool, To transmit the side link control information and corresponding data using the resource pool indicated by the first entry of the GNSS-based V2X communication transport exception pool (or the GNSS-based V2X communication transport exception pool). Alternatively, if the terminal receives an RRC reconfiguration message containing mobility control information, if the T304 timer is in operation and the PCell or source or target base station broadcasts system information including a GNSS-based V2X communication transport exception pool, The terminal is configured to transmit the side link control information and corresponding data to the lower layer using the resource pool indicated by the first entry of GNSS-based V2X communication transmission exception pool (or GNSS-based V2X / side-link communication transmission exception pool) do.

As described above, according to the present embodiments, when the RRC CONNECTED terminal according to the conventional LTE technology intends to perform direct communication for the V2X service, it can reduce the transmission / reception delay or interruption in the process of handover according to the movement of the terminal, And provides an effect to perform the operation.

Hereinafter, configurations of a terminal and a base station capable of performing a part or all of the above-described embodiments will be described with reference to the drawings.

7 is a diagram for explaining a terminal configuration according to an embodiment.

Referring to FIG. 7, a terminal 700 for performing vehicle communication includes a controller 710 that configures synchronization for vehicle communication using synchronization type information for vehicle communication received from a source base station, And a receiver 730 that receives handover command information including resource configuration information for vehicle communication from the source base station. In addition, the control unit 710 can perform the vehicle communication until completion of the handover to the target base station using the resource configuration information.

Receiver 730 may receive synchronization type information for vehicle communication from the source base station. The synchronization type information may include information on whether the synchronization to be used is base station based, information on GNSS based awareness, or information indicating a priority related thereto, when the terminal performs vehicle communication.

Also, the receiver 730 can receive measurement configuration information used for cell quality measurement and the like from the base station (source base station in the handover procedure) constituting the RRC connection.

If the resource configuration information includes synchronization configuration information indicating a synchronous configuration for the vehicle communication before the handover is completed, the controller 710 may configure the synchronization of the terminal until completion of the handover using the synchronization configuration information . The resource configuration information may be included in the handover command information, and the handover command information may be included in the mobility control information. Meanwhile, the resource configuration information is set based on the handover preparation information transmitted from the source base station to the target base station. The handover preparation information includes the vehicle communication configuration information configured by the source base station, the Global Navigation Satellite System (GNSS) And terminal capability information. For example, the vehicle communication configuration information may include the above-described synchronization type information configured in the terminal by the source base station.

In addition, the control unit 710 performs V2X communication using the resource configuration information set by the target base station in the handover process when the UE performing the vehicle communication necessary for performing the above-described embodiments performs the handover And controls the overall operation of the terminal 700 in accordance with the operation.

The receiver 730 can receive downlink control information, data, and messages from the base station through the corresponding channel and receive data and control information from other terminals. In addition, the transmitter 720 may transmit uplink control information, data, and a message to the base station through the corresponding channel, and may transmit data and control information to the other terminal.

8 is a diagram for explaining a source base station configuration according to an embodiment.

8, in a source base station 800 that controls handover of a terminal performing vehicle communication, a source base station 800 includes a control unit 810 for determining a handover of a terminal performing vehicle communication, A transmitter 820 for transmitting handover preparation information including at least one of configuration information, Global Navigation Satellite System (GNSS) status information of the terminal, and terminal capability information to a target base station, and a resource And a receiving unit 830 for receiving the configuration information, and the transmitting unit 820 can transmit the handover command information including the resource configuration information to the terminal.

As described above, the vehicle communication configuration information may include synchronization type information configured in the terminal, and the synchronization type information may include information indicating whether the terminal is a base station based synchronization type or a GNSS based synchronization type.

In addition, the transmitter 820 transmits an RRC connection reconfiguration message including handover command information to the UE, and the handover command information can be included in the mobility control information. The resource configuration information may include information indicating a vehicle communication radio resource to be used by the terminal before completion of the handover of the terminal. Alternatively, the resource configuration information may include synchronization configuration information to be configured by the UE until completion of handover of the terminal. That is, the vehicle communication configuration information includes information indicating which type of synchronization is configured or used by the terminal.

In addition, the control unit 810 controls the source base station to transmit the target communication signal to the target base station in order to prevent the terminal, which is performing the vehicle communication necessary to perform the above-described embodiments, from interrupting or delaying data transmission / And controls the overall operation of the base station 800 according to the transfer of the configuration information to the terminal.

The transmitting unit 820 and the receiving unit 830 are used to transmit and receive signals, messages, and data necessary for performing the above-described embodiments to or from the terminal or the target base station.

The standard content or standard documents referred to in the above-mentioned embodiments constitute a part of this specification, for the sake of simplicity of description of the specification. Therefore, it is to be understood that the content of the above standard content and portions of the standard documents are added to or contained in the scope of the present invention.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (20)

A handover method of a terminal performing a vehicle to everything (V2X)
Receiving and configuring synchronization type information for vehicle communication from a source base station;
Receiving, from the source base station, handover command information including resource configuration information for vehicle communication set by a target base station; And
Performing the vehicle communication until completion of handover to the target base station using the resource configuration information,
Wherein the resource configuration information comprises:
A radio resource pool information and synchronization configuration information for vehicle communication of the target base station,
The target base station,
And receiving the synchronization type information of the source base station included in the AS configuration field of the handover preparation information from the source base station to set the resource configuration information. The method according to claim 1,
Wherein performing the vehicle communication comprises:
When the resource configuration information includes the synchronization configuration information indicating a synchronous configuration for vehicle communication of the terminal until the completion of the handover, Car communication is performed. delete The method according to claim 1,
The handover preparation information includes:
Wherein the source base station comprises at least one of vehicle communication configuration information configured by the source base station, global navigation satellite system status information of the terminal, and terminal capability information. delete A method for controlling handover of a terminal that performs source-to-vehicle communication (vehicle to everything; V2X)
Determining handover of a terminal performing vehicle communication;
Transmitting handover preparation information including at least one of vehicle communication configuration information configured by the source base station, global navigation satellite system status information of the terminal, and terminal capability information to the target base station;
Receiving resource configuration information for vehicle communication of the terminal from the target base station; And
And transmitting the handover command information including the resource configuration information to the terminal,
Wherein the resource configuration information comprises:
A radio resource pool information and synchronization configuration information for vehicle communication of the target base station,
The vehicle communication configuration information configured by the source base station includes:
The handover preparation information included in the AS configuration field of the handover preparation information,
Wherein the terminal performs the vehicle communication until completion of the handover using the radio resource pool information and the synchronization configuration information for vehicle communication of the target base station. The method according to claim 6,
The vehicle communication configuration information includes:
And synchronization type information configured to the terminal by the source base station. 8. The method of claim 7,
Wherein the synchronization type information comprises:
The information indicating whether the terminal is a base station based sync type or a GNSS based sync type. delete delete In a terminal performing a vehicle to everything (V2X)
A control unit for receiving and configuring synchronization type information for vehicle communication from a source base station; And
And a receiving unit for receiving, from the source base station, handover command information including resource configuration information for vehicle communication set by the target base station,
Wherein the control unit performs the vehicle communication until completion of handover to the target base station using the resource configuration information,
Wherein the resource configuration information comprises:
A radio resource pool information and synchronization configuration information for vehicle communication of the target base station,
The target base station,
And receiving the synchronization type information of the source base station included in the AS configuration field of the handover preparation information from the source base station and setting the resource configuration information. 12. The method of claim 11,
Wherein,
When the resource configuration information includes the synchronization configuration information indicating a synchronous configuration for vehicle communication of the terminal until the completion of the handover, And performs vehicle communication. delete 12. The method of claim 11,
The handover preparation information includes:
Wherein the source base station comprises at least one of vehicle communication configuration information configured by the source base station, global navigation satellite system status information of the terminal, and terminal capability information. delete A source base station for controlling handover of a terminal performing a vehicle to everything (V2X)
A control unit for determining a handover of a terminal performing vehicle communication;
A transmission unit configured to transmit handover preparation information including at least one of vehicle communication configuration information configured by the source base station, global navigation satellite system status information of the terminal, and terminal capability information to the target base station; And
And a receiver for receiving resource configuration information for vehicle communication of the terminal from the target base station,
Wherein the transmitting unit further transmits handover command information including the resource configuration information to the terminal,
Wherein the resource configuration information comprises:
A radio resource pool information and synchronization configuration information for vehicle communication of the target base station,
The vehicle communication configuration information configured by the source base station includes:
The handover preparation information included in the AS configuration field of the handover preparation information,
Wherein the terminal performs vehicle communication until completion of the handover using radio resource pool information and synchronization configuration information for vehicle communication of the target base station. 17. The method of claim 16,
The vehicle communication configuration information includes:
Wherein the source base station comprises synchronization type information configured by the source base station to the terminal. 18. The method of claim 17,
Wherein the synchronization type information comprises:
Wherein the source base station comprises information indicating whether the terminal is a base station based sync type or a GNSS based sync type. delete delete

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