KR20170036623A - Operation method of communication node supporting direct communication in network - Google Patents

Abstract

Disclosed is a method for operating a communication node supporting direct communication in a network. A method for operating first user equipment (UE) comprises the steps of: acquiring scheduling information set for direct communication from a first base station to which the first UE belongs; checking modulation and coding scheme (MCS) information and wireless resource information included in the scheduling information; and transmitting a first message to which an MCS instructed by the MCS information is applied to a second UE through a wireless resource instructed by the wireless resource information. Therefore, performance of a communication network can be improved.

Description

TECHNICAL FIELD [0001] The present invention relates to an operation method of a communication node supporting direct communication in a network,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to direct communication technology, and more particularly, to a method of operating a communication node supporting vehicle communication based on a cellular system.

The wireless access for vehicular environments (WAVE) protocol is a protocol that supports vehicle communication and can support vehicle to everything (V2X) communication. V2X communication may include vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) communication, and in-vehicle networking (IVN) communication.

According to the WAVE protocol, seven channels can be supported in the 5.85 to 5.925 GHz frequency band (ie, 75 MHz bandwidth). Seven channels can be used for V2X communication. One of the seven channels may be used for transmission and reception of control information, and may be referred to as a control channel (CCH). Of the seven channels, the remaining six channels may be used for traffic safety related services, general commercial services, etc., and may be referred to as service channels (SCHs).

In a vehicular communication environment, coverage (e.g., coverage) of a roadside unit (RSU) may overlap with coverage of an adjacent RSU to ensure continuity of service. The frequency used by the RSU may be different from the frequency used by the adjacent RSU. In this case, if the service between the RSU and the OBU (onboard unit) and the service between OBUs belonging to different coverage are simultaneously provided, frequency interference may occur in one physical layer.

Meanwhile, the technology as the background of the invention is intended to enhance understanding of the background of the invention, and may include contents that are not known to the person of ordinary skill in the art.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of operating a communication node supporting vehicle communication based on a cellular system.

According to an aspect of the present invention, there is provided a method of operating a first UE supporting direct communication in a communication network, the method comprising: acquiring scheduling information set for direct communication from a first base station to which the first UE belongs; The method comprising: checking MCS information and radio resource information included in the scheduling information; and transmitting a first message to which the MCS indicated by the MCS information is applied, to a second UE .

Here, the state of the first UE may be an RRC connected state or an RRC id state.

Here, the scheduling information may be shared by the first base station and the second base station to which the second UE belongs.

Here, the radio resource indicated by the radio resource information may be set based on the speed of the vehicle where the first UE is located, the density of the vehicle in the zone to which the first UE belongs, or the service coverage of the direct communication.

Here, when the mode 1 scheme is used, the radio resource information may indicate a radio resource selected by the first base station from the direct communication resource pool, and when the mode 2 scheme is used, You can indicate a pool of resources.

Here, the MCS information may indicate an MCS index or an MCS range set by the first base station.

Here, the MCS indicated by the MCS information may be set based on the speed of the vehicle where the first UE is located, the density of the vehicle in the zone to which the first UE belongs, or the service coverage of the direct communication.

Here, the communication between the first base station and the first UE may be performed through the Uu interface, and the direct communication between the first UE and the second UE may be performed through the PC5 interface.

Here, the first base station may be a first RSU belonging to a vehicle communication network, the first UE may be a first OBU belonging to the vehicle communication network, and the second UE may be a second RSU belonging to a second It can be an OBU.

Here, the method of operation of the first UE comprises the steps of: acquiring a communication resource pool directly from the first base station; performing a monitoring operation on radio resources belonging to the direct communication resource pool; And receiving a second message from the second UE.

Here, the operation method of the first UE may include: requesting the first base station to allocate additional radio resources for direct communication when the radio resource can not be used; acquiring additional radio resource information from the first base station; And transmitting a third message to the second UE via the additional radio resource indicated by the additional radio resource information.

Here, the first UE may request allocation of the additional radio resource to the first base station based on a random access procedure, a scheduling request procedure of a PUCCH, or a BSR procedure.

Here, the additional radio resource may be selected from radio resources other than the radio resources used for the transmission of the first message among the direct communication resource pool.

According to another aspect of the present invention, there is provided a method of operating a first UE supporting direct communication in a communication network, the method comprising the steps of: if the direct communication between the first UE and the second UE is terminated, Transmitting a first message requesting termination to a first base station to which the first UE belongs and performing a release operation of the radio resource or a release operation of the RRC connection with the first base station for the termination of the direct communication The first UE operates in an RRC connection state when the radio resource is released, and the first UE operates in an RRC idle state when the RRC connection release operation is performed.

Here, the method of operating the first UE may include requesting the first base station to allocate radio resources for the direct communication when the direct communication between the first UE and the second UE is requested in an RRC connected state, Obtaining radio resource information from the first base station, and transmitting a second message to the second UE via the radio resource indicated by the radio resource information.

Here, the method of operation of the first UE comprises: selecting a radio resource from a direct communication resource pool obtained from the base station if the direct communication between the first UE and the second UE is requested in an RRC idle state; And transmitting a third message via the radio resource to the second UE.

Here, the direct communication resource pool may be set based on the speed of the vehicle where the first UE is located, the density of the vehicle in the zone to which the first UE belongs, or the service coverage of the direct communication.

Here, the direct communication radio resource pool may be shared by the first base station and the second base station to which the second UE belongs.

Here, the MCS applied to the third message may be set based on the speed of the vehicle where the first UE is located, the density of the vehicle in the zone to which the first UE belongs, or the service coverage of the direct communication.

Here, the first base station may be a first RSU belonging to a vehicle communication network, the first UE may be a first OBU belonging to the vehicle communication network, and the second UE may be a second RSU belonging to a second It can be an OBU.

According to the present invention, vehicle communication (e.g., V2V communication, V2I communication, V2P communication, INV communication, etc.) can be supported based on a cellular system. In addition, an autonomous travel system, an intelligent transportation system (ITS), and the like can be efficiently constructed. Therefore, the performance of the communication system can be improved.

1 is a conceptual diagram showing an embodiment of a wireless communication network.
2 is a block diagram illustrating an embodiment of a communication node constituting a wireless communication network.
3 is a conceptual diagram showing a first scenario of D2D communication.
4 is a conceptual diagram showing a second scenario of D2D communication.
5 is a conceptual diagram showing a third scenario of D2D communication.
6 is a conceptual diagram showing a fourth scenario of the D2D communication.
7 is a flowchart illustrating a method of transmitting a periodic message performed at a communication node.
8 is a conceptual diagram showing an embodiment of a vehicle communication network.
9 is a conceptual diagram showing a deployment scenario of a cellular communication network.
10 is a conceptual diagram showing a deployment scenario of a vehicle communication network.
11 is a flow chart illustrating an embodiment of a communication method performed by a communication node in a vehicle communication network.
12 is a flowchart showing an embodiment of a communication method based on a visual communication in a vehicle communication network.
13 is a timing diagram showing an embodiment of a message transmission method over a PRB.
Fig. 14 is a timing chart showing an embodiment of a repetitive data transmission method. Fig.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

A wireless communication network to which embodiments of the present invention are applied will be described. The wireless communication networks to which the embodiments according to the present invention are applied are not limited to those described below, and the embodiments according to the present invention can be applied to various wireless communication networks. Here, the wireless communication network may be used in the same sense as a wireless communication system.

1 is a conceptual diagram showing an embodiment of a wireless communication network.

Referring to FIG. 1, a wireless communication network 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3 , 130-4, 130-5, 130-6). Each of the plurality of communication nodes may support at least one communication protocol. For example, each of the plurality of communication nodes may be a wireless communication device based on a communication protocol based on a code division multiple access (CDMA) communication protocol, a communication protocol based on a wideband CDMA (WCDMA), a communication protocol based on a time division multiple access (TDMA) based communication protocol, an orthogonal frequency division multiplexing (OFDM) based communication protocol, an OFDMA (orthogonal frequency division multiple access) based communication protocol, a single carrier-FDMA based communication protocol, a non-orthogonal multiple access based communication protocol, a space division multiple access (SDMA) based communication protocol, a radio access technology supporting multiple access based on beamforming technology by a massive antenna, technology (RAT) based communication protocol. Each of the plurality of communication nodes may have the following structure.

2 is a block diagram illustrating an embodiment of a communication node constituting a wireless communication network.

Referring to FIG. 2, the communication node 200 may include at least one processor 210, a memory 220, and a transceiver 230 connected to the network to perform communication. The communication node 200 may further include an input interface device 240, an output interface device 250, a storage device 260, and the like. Each component included in the communication node 200 may be connected by a bus 270 and communicate with each other.

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260. The processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods in accordance with embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be constituted of at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 220 may comprise at least one of read-only memory (ROM) and random access memory (RAM).

Referring again to FIG. 1, each of the plurality of communication nodes may be a base station or a user equipment (UE). Each of the first base station 110-1, the second base station 110-2 and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the UE3 130-3 and the UE4 130-4 may belong to the coverage of the first base station 110-1. Within the coverage of the second base station 110-2, UE2 130-2, UE4 130-4 and UE5 130-5 may belong. The fifth base station 120-2, the UE4 130-4, the UE5 130-5 and the UE6 130-6 may belong to the coverage of the third base station 110-3. UE1 130-1 may belong to the coverage of the fourth base station 120-1. Within the coverage of the fifth base station 120-2, UE6 130-6 may belong.

Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1 and 120-2 includes a Node B, an evolved Node B, a base transceiver station (BTS) A radio base station, a radio transceiver, an access point, an access node, a road side unit (RSU), a radio remote head (RRH), a transmission point (TP) transmission and reception points, relays, and the like. Each of the plurality of UEs 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 includes a terminal, an access terminal, a mobile terminal, May be referred to as a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, an on board unit (OBU) .

A plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, Each may support cellular communication (e.g., long term evolution (LTE), LTE-A (advanced), etc. defined in 3GPP standards). Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands, or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1 and 120-2 may be interconnected via an ideal backhaul link or a non-idle backhaul link , An idle backhaul link, or a non-idle backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, 120-2 may be connected to a core network (not shown) via an ideal backhaul link or a non- have. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to specific UEs 130-1, 130-2, 130-3, 130 130-2, 130-3, 130-4, 130-5, and 130-6, and transmits the signals received from the specific UEs 130-1, 130-2, 130-3, 130-4, Lt; / RTI >

Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 can support downlink transmission based on OFDMA, and uplink ) Transmission. Also, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may perform multiple input multiple output (MIMO) transmission (for example, A coordinated multipoint (CoMP) transmission, a carrier aggregation (CA) transmission, a transmission in an unlicensed band, a device to device communication (D2D) (E.g., proximity service (ProSe)), and the like. Each of the plurality of UEs 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6 includes base stations 110-1, 110-2, 110-3, and 120-1 , 120-2, and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2.

For example, the second base station 110-2 may transmit a signal to the UE4 130-4 based on the SU-MIMO scheme, and the UE4 130-4 may transmit a signal based on the SU-MIMO scheme to the second base station 0.0 > 110-2. ≪ / RTI > Alternatively, the second base station 110-2 may transmit a signal to the UE4 130-4 and the UE5 130-5 based on the MU-MIMO scheme, and the UE4 130-4 and the UE5 130-5 May receive signals from the second base station 110-2 by the MU-MIMO scheme. Each of the first base station 110-1, the second base station 110-2 and the third base station 110-3 can transmit a signal to the UE4 130-4 based on the CoMP scheme, 4 can receive signals from the first base station 110-1, the second base station 110-2 and the third base station 110-3 by the CoMP method. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 includes UEs 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6) and the CA scheme. Each of the first base station 110-1, the second base station 110-2 and the third base station 110-3 coordinates the D2D communication between the UE4 130-4 and the UE5 130-5 And each of UE4 130-4 and UE5 130-5 can perform D2D communication by the coordination of each of second base station 110-2 and third base station 110-3.

Next, methods of operating the communication node in the wireless communication network will be described. Even if a method (e.g., transmission or reception of a signal) to be performed at the first communication node among the communication nodes is described, the corresponding second communication node is controlled by a method corresponding to the method performed at the first communication node For example, receiving or transmitting a signal). That is, when the operation of the UE is described, the corresponding base station can perform an operation corresponding to the operation of the UE. Conversely, when the operation of the base station is described, the corresponding UE can perform an operation corresponding to the operation of the base station.

On the other hand, public safety communication technologies based on the LTE / LTE-A system (for example, disaster communication technology) include earthquake and tsunami warning system (ETWS), public warning system (PWS), D2D communication A GCSE (group communication service), and the like. Here, in the D2D communication and the GCSE, communication can be performed over the radio channel between the UEs via the base station. The functions of D2D communication can be classified into functions of commercial services, functions of public safety, and so on. The scenario of D2D communication may be as follows.

3 is a conceptual diagram showing a first scenario of D2D communication.

Referring to FIG. 3, each of UE1 310 and UE2 410 may be located outside the coverage of the base station. For example, if there is a message to be sent to UE2 410, UE1 310 may send the message directly to UE2 410. [ UE1 310 may also receive the message directly from UE2 410. < RTI ID = 0.0 > That is, the UE1 310 and the UE2 410 can send and receive messages based on the D2D communication. The resource allocation operation and the control signaling operation for D2D communication can be basically performed based on a distributed control scheme.

4 is a conceptual diagram showing a second scenario of D2D communication.

Referring to FIG. 4, UE1 310 may be located within the coverage of first base station 300 and second terminal 210 may be located beyond the coverage of first base station 300. This case may be referred to as a " partial coverage scenario ". For example, if there is a message to be sent to UE2 410, UE1 310 may send the message directly to UE2 410. [ UE1 310 may also receive the message directly from UE2 410. < RTI ID = 0.0 > That is, the UE1 310 and the UE2 410 can send and receive messages based on the D2D communication. The resource allocation and control signaling operations for D2D communication may be performed based on a distributed control scheme or a base station control scheme (or a network control scheme).

5 is a conceptual diagram showing a third scenario of D2D communication.

Referring to FIG. 5, each of UE1 310 and UE2 410 may be located within the coverage of the first base station 300. For example, if there is a message to be sent to UE2 410, UE1 310 may send the message directly to UE2 410. [ UE1 310 may also receive the message directly from UE2 410. < RTI ID = 0.0 > That is, the UE1 310 and the UE2 410 can send and receive messages based on the D2D communication. When the UEs 310 and 410 are located within the coverage of the first base station 300, the resource allocation and control signaling operations for D2D communication are basically performed based on the base station control method (or network control method) .

6 is a conceptual diagram showing a fourth scenario of the D2D communication.

Referring to FIG. 6, UE1 310 may be located within the coverage of first base station 300 and UE2 410 may be located within coverage of second base station 400. Referring to FIG. For example, if there is a message to be sent to UE2 410, UE1 310 may send the message directly to UE2 410. [ UE1 310 may also receive the message directly from UE2 410. < RTI ID = 0.0 > That is, the UE1 310 and the UE2 410 can send and receive messages based on the D2D communication. When the UEs 310 and 410 are located within the coverage of the base stations 300 and 400, the resource allocation and control signaling operations for D2D communication are basically performed based on the base station control method (or network control method) .

Meanwhile, in the LTE / LTE-A system, D2D communication can support voice service and support voice service based on one quality of service (QoS). A UE supporting D2D communication can transmit data using a broadcast scheme or a multicast scheme instead of the unicast scheme. If the UE is located within the coverage of the base station, the D2D communication may be performed based on mode 1. When Mode 1 is used in D2D communication, the base station can inform the UE of resource information (e.g., radio resource information) used for D2D communication. For example, the base station may allocate to the UE resources available (e.g., available radio resources) in the D2D communication resource pool. The UE may perform D2D communication using resources (e.g., allocated radio resources) allocated by the base station. Thus, D2D communication can be performed without collision between UEs.

If the UE is located outside the coverage of the base station, D2D communication may be performed based on mode 2. When Mode 2 is used in D2D communication, the UE may randomly select a resource (e.g., a radio resource) in the D2D communication resource pool set by the communication system, and the selected resource (e.g., Resources) can be used to perform D2D communication. Resources (e.g., radio resources) used for D2D communication are randomly selected, so that collisions between UEs can occur.

In partial coverage scenarios, D2D communication may be performed based on mode 1 or mode 2. The criterion for selecting the mode may be preset, and the UE may select Mode 1 or Mode 2 according to a predetermined criterion, and the D2D communication is performed using the resource determined by the selected mode (e.g., determined radio resource) Can be performed.

Direct communication can be performed based on the D2D communication technology described above. Direct communications may include D2D communications, vehicle communications, machine type communications (MTC), machine to machine (M2M) based communications, and Internet based (IoT) based communications. The vehicle communication may be a vehicle to everything (V2X) communication. V2X communication may include vehicle to vehicle (V2V) communication, vehicle to infrastructure (V2I) communication, vehicle to pedestrian (V2P) communication, and in-vehicle networking (IVN) communication. Communication between OBUs, communication between OBU and RSU, and communication between RSUs can be performed based on D2D communication technology. A discovery service, communication service between communication nodes based on vehicle communication can be provided.

In the embodiments to be described below, the RSU may be a communication system, a base station, etc., and the OBU may be a UE or the like. The UE may be a UE owned by a pedestrian, a UE owned by a person using a vehicle (e.g., a vehicle, a motorcycle, a bicycle, a wheelchair, a baby carriage, etc.) Based on a measurement function of the UE (for example, a function of measuring a moving distance per unit time, a function of measuring a change in received signal strength, etc.) or a sensor included in the UE (e.g., a gyro sensor) User information (for example, information indicating whether the owner of the UE is a pedestrian, information indicating whether the owner of the UE is the user of the moving means, etc.) can be automatically set. Alternatively, the user information may be set according to an input of a user of the corresponding UE.

When mode 1 is used, vehicle communication may be performed using resources scheduled by a base station (e.g., a communication system, RSU). If mode 2 is used, vehicle communication may be performed using a randomly selected resource in the vehicle communication resource pool set by the base station. The vehicle communication resource pool may be the same as or different from the D2D communication resource pool described above.

When Mode 1 is used, the OBU (or UE) can operate in a radio resource control (RRC) connected state, and the base station can control the management and allocation of resources. For example, the base station can directly set the mode of the vehicle communication (e.g., mode 1 or mode 2). An RRC idle OBU can operate in an RRC connection state when data to be transmitted is generated. That is, the state of the OBU may transition from the RRC idle state to the RRC connected state. The OBU, which is in the RRC connection state, can request the base station to allocate resources for vehicle communication. If necessary, the OBU, which is in the RRC connection state, can transmit a buffer status report (BSR) to the base station. When a resource allocation for vehicle communication is requested from the OBU, the base station can allocate available resources in the vehicle communication resource pool to the OBU. The OBU can transmit data using resources allocated by the base station. Also, the base station can allocate resources for the OBU, which is an RRC idle state, based on a semi-persistence scheduling (SPS) scheme. In this case, the OBU, which is the RRC idle state, can transmit data without collision by using the resources allocated by the base station.

Regardless of the state of the OBU (or UE) (e.g., the RRC connection state or the RRC idle state) when Mode 2 is used, the OBU can randomly select resources in the vehicle communication resource pool set by the base station , The data can be transmitted using the selected resource. On the other hand, the OBU can receive a synchronization signal from another communication node (e.g., base station, RSU, OBU, UE, etc.) and synchronize based on the synchronization signal, Can be transmitted. The synchronization signal may be transmitted in a broadcast manner from any communication node (e.g., base station, RSU, OBU, UE, etc.) via a resource configured for transmission of the synchronization signal. If no synchronization signal is detected, the OBU can directly transmit the synchronization signal. That is, the OBU can operate as a synchronization source.

In the following, the manner in which resources for direct communication (e.g., D2D communication, vehicular communication, etc.) are allocated by the base station may be referred to as the " mode 1 scheme ". The resources allocated by the mode 1 scheme may be referred to as "mode 1 resources ". The manner in which resources for direct communication (e.g., D2D communication, vehicle communication, etc.) are randomly selected by the OBU in a pre-established vehicle communication resource pool may be referred to as a " mode 2 scheme. &Quot; The resource selected by the mode 2 scheme may be referred to as "mode 2 resource ".

Meanwhile, a message periodically generated in the vehicle communication (hereinafter referred to as a "periodic message") can be transmitted using the mode 1 resource regardless of the state of the OBU (for example, the RRC connection state or the RRC idle state) . A message generated by the occurrence of a specific event (hereinafter referred to as an "aperiodic message") may be transmitted using mode 2 resources. An aperiodic message may be transmitted using Mode 1 resources depending on attributes such as required reliability, service coverage, latency, and the like.

The OBU may include an AS layer block and an upper layer (e.g., a NAS (non-access stratum) layer or an application layer )) ≪ / RTI > The AS layer may be a physical layer (e.g., layer 1), a medium access control (MAC) layer (e.g., layer 2), or a radio resource control (RRC) layer.

The OBU can cancel or omit transmission of periodic messages. For example, when radio resources for transmission of a periodic message are not allocated, radio resources for transmission of a periodic message are not selected, or when an instruction of an upper layer requesting cancellation or omission of periodic message transmission For example, if there is a set condition, the transmission of the periodic message may be canceled or omitted. If the transmission of the periodic message fails due to cancellation, omission, or other reasons, the OBU may transmit the periodic message in an aperiodic manner, or may transmit an updated periodic message at the next transmission period (or at the time of transmission) have.

Specifically, the AS layer block can obtain a periodic message from the NAS layer block, and can transmit the periodic message according to a predetermined period. If the periodic message fails to be transmitted, the AS layer block (e.g., the physical layer block, MAC layer block, or RRC layer block included in the AS layer block) indicates a transmission failure (or cancellation or omission) of the periodic message A signaling parameter (or a primitive message between layer blocks included in the OBU) or a separate control message to a NAS layer block (e.g., a block supporting the control function). In addition, the reason for the transmission failure (or cancellation, omission) of the periodic message can also be reported to the NAS layer block.

The NAS layer block can confirm the failure (or cancellation, omission) of transmission of the periodic message by receiving signaling parameters or a separate control message from the AS layer block. Alternatively, the NAS layer block can identify the failure (or cancel, omit) of the transmission of the periodic message through other methods. In this case, the NAS layer block may instruct (e.g., trigger the AS layer block) to the AS layer block to transmit the periodic message in an aperiodic manner. Alternatively, the NAS layer block may instruct (e.g., activate the AS layer block) the AS layer block to send an updated periodic message at the next transmission period (or at the next transmission time). Alternatively, the NAS layer block may instruct the AS layer block to omit the periodic message transmission (e.g., activate the AS layer block).

On the other hand, the NAS layer block can control the occurrence frequency (or transmission period) of the periodic message. In addition, the NAS layer block can maintain and manage the updated latest information, and can control the transmission of the updated information updated at the next transmission period (or the next transmission time). The NAS layer block stores the signaling parameters (or a primitive message between layer blocks included in the OBU) or a signaling parameter It can be transmitted to the AS layer block through the control message.

The NAS layer block generates the frequency (or transmission period) of the periodic message based on the movement speed of the OBU (or UE) acquired in advance, the wireless channel environment, and the reason (or cancel, omission) Can be adjusted. Alternatively, the NAS layer block may include a signaling parameter (or a primitive message between layer blocks included in the OBU) requesting reporting of OBU movement speed, radio channel environment, reason of failure (or cancellation, omission) Alternatively, a separate control message may be transmitted to the AS layer block, and a periodic message may be generated based on the OBU movement speed reported from the AS layer block, the wireless channel environment, and the reason (or cancellation, omission) The frequency (or transmission period) can be adjusted.

The AS layer block can acquire the frequency (or transmission period) information of the periodic message from the NAS layer block, control information related to maintenance / management / transmission of the updated latest information. The AS layer block may transmit a periodic message according to the occurrence frequency (or transmission period). The AS layer block can maintain / manage / transmit the updated information based on the control information. The AS layer block can transmit the retention / management / transmission result of the updated information as a result of transmission of the periodic message to the NAS layer block. In addition, the AS layer block may report to the NAS layer block the movement speed of the OBU, the wireless channel environment, and reasons for failure (or cancellation or omission) of periodic message transmission according to the request of the NAS layer block.

The operation of adjusting the occurrence frequency (or transmission period) of the periodic message and the maintenance / management / transmission of the updated information may be performed in the RRC layer block belonging to the AS layer block instead of the NAS layer block have. In this case, the NAS layer block may transmit to the RRC layer block the control information related to the adjustment of the occurrence frequency (or the transmission period) of the periodic message and the maintenance / management / transmission related control information of the updated latest information. The RRC layer block can control the occurrence frequency (or transmission period) of the periodic message using the control information obtained from the NAS layer block, and can perform the maintenance / management / transmission related operation of the updated information. For example, the RRC layer block may include a signaling parameter (or a primitive message between layer blocks included in the OBU) requesting to operate based on the modulated occurrence frequency (or transmission period) of the periodic message or a separate control message To the MAC layer block and the physical layer block. In addition, the RRC layer block may transmit a signaling parameter (or a primitive message between layer blocks included in the OBU) requesting to perform the maintenance / management / transmission related operation of the updated latest information or a separate control message to the MAC layer block To the physical layer block. When a signaling parameter (or a primitive message between layer blocks included in the OBU) or a separate control message is received from the RRC layer block, the MAC layer block and the physical layer block generate a periodic message based on the request of the RRC layer block It is possible to adjust the frequency (or the transmission period) and perform the maintenance / management / transmission related operation of the updated latest information.

On the other hand, the condition for adjusting the occurrence frequency (or the transmission period) of the periodic message, the transmission cancellation (or omission) of the periodic message based on the control information of the NAS layer or the RRC control message (for example, control information of the RRC layer) And the like can be set in advance. If the current state meets a predetermined condition, the AS layer block (e.g., RRC layer block, MAC layer block, physical layer block) can adjust the occurrence frequency (or transmission period) of the periodic message, Can be canceled (or omitted). In this case, the AS layer block may report back to the NAS layer block the result of canceling (or omitting) the transmission of the periodic message as a result of adjusting the occurrence frequency (or transmission period) of the periodic message.

Next, a method of transmitting a periodic message performed in a communication node (e.g., OBU, UE) will be described. If Mode 1 resources are not allocated, no Mode 2 resources are selected, or if the transmission of a periodic message fails (or is aborted, omitted), the following transmission method may be used.

7 is a flowchart illustrating a method of transmitting a periodic message performed at a communication node.

7, the OBU (or UE) can compare the transmission delay time of the periodic message with the predetermined transmission delay time, or compare the number of transmission failure times of the periodic message with the preset number of transmission failure times (S700) . The preset transmission delay time and the preset number of transmission failure times can be set based on the attributes, priority, etc. of the periodic message. The OBU can acquire a predetermined transmission delay time and a preset transmission failure frequency through system information (or a separate control message).

Periodic transmission may be triggered if the transmission delay time of the periodic message is greater than or equal to a preset transmission delay time (or if the number of transmission failure times of the periodic message is greater than or equal to a preset number of transmission failure). If aperiodic transmission is triggered, the OBU may set resources for aperiodic transmission (S710). For example, the OBU may obtain Mode 1 resources allocated by the base station. Mode 1 resources may be allocated based on the Mode 1 scheme described above. Also, the OBU can report the latest information of the periodic message, the transmission delay time, the number of transmission failure times, the reason for the transmission failure, etc. to the base station in the mode 1 resource allocation procedure.

Alternatively, the OBU can select a Mode 2 resource. Mode 2 resources may be selected based on the mode 2 scheme described above. Also, the OBU (or UE) can report the latest information of the periodic message, the transmission delay time, the number of transmission failure times, the reason for the transmission failure, etc. to the base station in the mode 2 resource selection procedure. Alternatively, the OBU can obtain the uplink resources allocated by the base station. For example, the OBU may acquire uplink resources by performing an uplink resource request procedure (e.g., a scheduling request procedure) or an access procedure.

The OBU can determine whether the mode 1 resource or the mode 2 resource is available (S720). The OBU may send a periodic message using Mode 1 resources if Mode 1 resources are available, or a Periodic Message using Mode 2 resources if Mode 2 resources are available (S730). On the other hand, if both the mode 1 resource and the mode 2 resource are unavailable, the periodic message can be transmitted through the base station (S740). For example, the OBU can report the latest information of the periodic message, the transmission delay time, the number of transmission failure times, the reason for the transmission failure, etc. to the base station using the uplink resources. The latest information of the periodic message is received from the OBU, the base station can transmit the periodic message including the latest information to another communication node (e.g., OBU, UE, RSU, base station). In this case, the base station can transmit the periodic message through the downlink resource in a broadcast mode, a multicast mode, or a unicast mode. Alternatively, the base station may transmit the periodic message using the PC5 interface for vehicle communication.

8 is a conceptual diagram showing an embodiment of a vehicle communication network.

8, the MME1 / GW1 (gateway 1) 811, the MME2 / GW2 812, the base station 1 821, the base station 2 822, the RSU1 831, the RSU2 832 ), UE1 841, UE2 842, OBU1 851, OBU2 852, etc. may support direct communication (e.g., D2D communication, vehicle communication, etc.). Each of the base station 1 821 and the base station 2 822 may be connected to the MME1 / GW1 811, the MME2 / GW2 812, and the like via the S1 interface. Each of the base station 1 821 and the base station 2 822 can transmit and receive control information to and from the MME1 / GW1 811 and the MME2 / GW2 812 through a control plane, (811), MME2 / GW2 (812), and the like. The first base station 821 may be connected to the second base station 822 via the X2 interface.

The RSU1 831 may be connected to the base station 1 821 through the X2 interface and may be connected to the MME1 / GW1 811 through the S1 interface when the RSU1 831 supports the base station function. The RSU1 831 can perform transmission / reception of control information / data through the X2 interface and the S1 interface. Here, the S1 interface may be a logical interface, and the RSU1 831 may physically be connected to the MME1 / GW1 811 via the base station 1 821. [ Alternatively, the RSU1 831 may be connected to the first base station 821 via the Un interface when the RSU1 831 supports the relay function (for example, the L3 / L2 relay function), and transmits / receives the control information / Can be performed. Alternatively, the RSU1 831 may be connected to the first base station 821 via the Uu interface when performing the UE (or OBU) function, and may perform transmission / reception of control information / data through the Uu interface.

The RSU2 832 can be connected to the second base station 822 via the Un interface when the RSU2 832 supports the relay function (for example, the L3 / L2 relay function), and performs transmission / reception of control information / data through the Un interface can do. Alternatively, the RSU2 832 may be connected to the second base station 822 via the Uu interface when performing the UE (or OBU) function, and may perform transmission / reception of control information / data through the Uu interface. The RSU1 831 can be connected to the RSU2 832 via the PC5 interface or the Uu interface. The transmission / reception of control information / data between the RSU1 831 and the RSU2 832 can be performed through the PC5 interface or the Uu interface.

UE1 841 may be coupled to base station 1 821 via the Uu interface and may be coupled to OBU1 851 via the PC5 interface. The UE1 841 can perform transmission / reception of control information / data through the Uu interface and the PC5 interface. UE2 842 may be coupled to base station 2 822 via a Uu interface and may be coupled to OBU2 852 via a PC5 interface. The UE2 842 can perform transmission / reception of control information / data through the Uu interface and the PC5 interface.

The OBU1 851 may be connected to the RSU1 831 supporting the base station function (or the relay function) through the Uu interface, the UE1 841 through the PC5 interface, the OBU2 852 and the PC5 interface Lt; / RTI > The OBU1 851 can perform transmission / reception of control information / data through the Uu interface and the PC5 interface. OBU2 852 may be connected to base station 2 822 via a Uu interface and may be connected via a PC5 interface with RSU2 832 supporting UE functionality (or OBU functionality) And may be connected to the OBU1 851 via the PC5 interface. The OBU2 852 can perform transmission / reception of control information / data through the Uu interface and the PC5 interface.

Here, the PC5 interface may be a PC5 interface for D2D communication in an LTE / LTE-A system or may be a wireless interface (for example, an RSU, OBU, UE, etc.) For example, a PC5 interface for vehicle communication).

9 is a conceptual diagram showing a deployment scenario of a cellular communication network.

Referring to FIG. 9, a base station can manage a plurality of cells (e.g., three cells). Each of the plurality of base stations can be operated by the same operator or different operators. In addition, the cellular communication network may be divided into a plurality of zones. A plurality of cells may be located in each zone, and a base station may be located. Alternatively, the base station may not be located in each zone. Here, the zone may be the same as the zone in the vehicle communication network described below.

10 is a conceptual diagram showing a deployment scenario of a vehicle communication network.

Referring to FIG. 10, the vehicle communication network may include a base station, an RSU, an OBU, a UE, and the like. RSUs can be located in traffic lights, traffic signs, structures on roads, structures around roads (eg street lights, telephone poles, street trees, etc.), buildings around roads, The RSU may perform a base station function, a relay function, or a UE function (or an OBU function). The OBU can be located on a mobile means. The UE may be a UE owned by a pedestrian, a UE owned by a person using the mobile means, or the like.

The zone may include at least one RSU, at least one OBU, at least one UE, and the like. The zone can be set in consideration of the moving speed, density, moving path, etc. of the vehicle (or OBU, UE). (E. G., Bandwidth, center frequency, etc.), physical layer configuration information (e. G., Synchronization < / RTI > (Or configuration information of a resource element) (or a resource block) in a radio frame (or a subframe), a configuration / configuration information of a direct communication resource pool Configuration / mapping information, etc. can be pre-exchanged between cells, so that cells in one zone can be operated in the same way. Here, the direct communication resource pool may be a D2D communication resource pool, a vehicle communication resource pool, or the like. In addition, the direct communication resource pool may include a resource pool for a discovery operation, a resource pool for data communication, and the like.

In the case where the operators of the respective cells in one zone or neighboring zones are different (for example, an inter-public land mobile network (inter-PLMN)), OBUs (or UEs) (Or resource blocks) in the radio frame (or subframe), for example, the information described above (e.g., frequency information, physical layer configuration information, Configuration / deployment information, direct communication resource pool configuration / mapping information, etc.) can be used equally. Further, based on the same connection procedure, control information / data transmission / reception operations can be performed.

On the other hand, a resource (for example, a vehicle communication resource pool) for direct communication in the vehicle communication network can be set based on the mode 1 scheme or the mode 2 scheme described above. An end node (e.g., base station, cell, access point, RSU, etc.) in the vehicle communication network may establish a vehicle communication resource pool based on at least one of the following parameters. Here, the vehicle communication resource pool can be set for each vehicle (or OBU, UE) or zone.

- road-related parameters (for example, the width of a lane, the number of lanes, the number of intersections, the form of an intersection, the type of road (for example, a city road, an arterial road, a back road, (For example, freezing, flooding, etc.), accident conditions, etc.)

(E.g., the number of vehicles (or OBU, UE) per unit area) of the vehicle (or OBU, UE) (Or OBU, UE) moving speed (e.g., average moving speed) of the vehicle (or OBU, UE)

- service-related parameters (e.g., service-specific coverage (e.g., reach by service), transmission reliability, etc.)

(E.g., a message transmission method (e.g., a cyclic manner, an aperiodic method (or an event method), etc.) of a message, a characteristic of the data included in the message Type, etc.)

- Operating time-related parameters (eg, hours of work, hours of work, weekdays, weekends, etc.)

For example, if a relatively large number of vehicles (or OBU, UE) are predicted to be present based on road related parameters, the vehicle communication resource pool may be set to include a relatively large number of resources. Conversely, when relatively few vehicles (or OBU, UE) are predicted to exist based on road related parameters, the vehicle communication resource pool can be set to include relatively few resources.

If it is determined that there are relatively many vehicles (or OBU, UE) based on the vehicle-related parameters, the vehicle communication resource pool can be set to include a relatively large amount of resources. Conversely, if it is determined that there are relatively few vehicles (or OBU, UE) based on the vehicle-related parameters, the vehicle communication resource pool can be set to include relatively few resources. In addition, if the vehicle speed is less than or equal to a predetermined threshold (or the density of the vehicle exceeds a predetermined threshold), the vehicle communication resource pool may be set to include a relatively large amount of resources. Conversely, when the speed of the vehicle exceeds a preset threshold value (or when the density of the vehicle is less than or equal to a preset threshold), the vehicle communication resource pool can be set to include relatively few resources.

Here, the OBU (or UE) may report the vehicle-related parameters to the base station (or RSU). Alternatively, the server connected to the OBU can estimate the vehicle-related parameters based on the information obtained from the vehicle's navigation system, and report the estimated vehicle-related parameters to the base station. Alternatively, when a base station is equipped with a sensor, a video device (for example, a closed circuit television (CCTV), a camera, etc.), the base station can estimate a vehicle-related parameter using a sensor, a video device, and the like.

If the coverage of the service is determined to be relatively large based on the service-related parameters, the vehicle communication resource pool can be set to include a relatively large amount of resources. Conversely, if the coverage of the service is determined to be relatively narrow based on the service-related parameters, the vehicle communication resource pool can be set to include relatively few resources.

If it is determined that the data to be transmitted is relatively large based on the message-related parameters, the vehicle communication resource pool can be set to include a relatively large amount of resources. Conversely, if it is determined that the data to be transmitted is relatively small based on the message-related parameters, the vehicle communication resource pool can be set to include relatively few resources.

When a relatively large number of vehicles (or OBU, UE) are predicted to exist based on the operation time-related parameters, the vehicle communication resource pool can be set to include a relatively large number of resources. Conversely, when relatively few vehicles (or OBU, UE) are predicted to be present based on operating time-related parameters, the vehicle communication resource pool can be set to include relatively few resources.

In addition, the base station can set a vehicle communication resource pool so that resources can be reused. For example, the base station may establish a vehicle communication resource pool such that different resources are allocated to each of the consecutive zones to reduce interference in vehicle communication. The base station may set the vehicle communication resource pool such that the same resources are allocated to each of the zones that are spaced apart (i. E., Non-contiguous zones).

The base station can transmit the configuration information of the vehicle communication resource pool to the OBU through the system information or the dedicated control message. The configuration information of the vehicle communication resource pool includes system bandwidth, transmission bandwidth, frequency resource information (e.g., a subcarrier index, etc.), time resource information (e.g., a subframe index, a slot index, (for example, priority), channel configuration information of the physical layer, effective time of configuration information of the vehicle communication resource pool, configuration information of the vehicle communication resource pool (E.g., a cell identifier, a tracking area identifier, a zone identifier, etc.), and an allocation scheme of a vehicle communication resource pool (mode 1, mode 2).

The OBU can receive the configuration information of the vehicle communication resource pool from the base station and can confirm the resources used for the vehicle communication based on the configuration information of the vehicle communication resource pool. Thus, the OBU can perform vehicle communication using the resources contained in the vehicle communication resource pool.

On the other hand, in vehicle communication, a modulation and coding scheme (MCS) can be set by the base station (or RSU) or the OBU (or UE). The base station can set the MCS using at least one of the above-described road related parameters, vehicle related parameters, service related parameters, message related parameters, and operation time related parameters. The base station can set a specific MCS index (e.g., MCS level) or an available MCS range. The MCS index (or MCS range) can be set for each vehicle (or OBU, UE) or zone. For example, when an MCS index (or MCS range) is set for each zone, OBUs belonging to the zone can use the same MCS index (or MCS range).

The base station can transmit the set MCS information (e.g., MCS index, MCS range) to the OBU through the system information or the dedicated control message. The OBU can receive MCS information from the base station. When an MCS index is received, the OBU can perform vehicle communication using the MCS indicated by the MCS index. When an MCS range is received, the OBU can select the MCS within the MCS range and can perform vehicle communication using the selected MCS.

On the other hand, a fixed MCS may be used in the base station and the OBU. For example, a fixed MCS may be used depending on the characteristics (e.g., priority, size, type, etc.) of the data included in the message. Alternatively, an MCS fixed to the zone (or road) may be used. When a fixed MCS is used, control information including scheduling information for resources used for data transmission to which a fixed MCS is applied (e.g., sidelink control (SC) in D2D communication based on LTE / LTE-A) Information) may not be transmitted. For example, a periodic message transmitted in a broadcast manner or a message containing data belonging to a predetermined size range may be transmitted using a fixed MCS without separate scheduling information. Particularly, when resources for vehicle communication are allocated by the SPS scheme, a fixed MCS can be usefully used. In addition, a message to which a fixed MCS is applied may be transmitted through a resource other than a resource to which a message to which an MCS set by the base station or the OBU is transmitted is transmitted.

On the other hand, the OBU can set the MCS using at least one of the road related parameter, the vehicle related parameter, the service related parameter, the message related parameter, and the operation time related parameter described above. Here, the preset threshold value used for determination of each parameter (for example, a road related parameter, a vehicle related parameter, a service related parameter, a message related parameter, an operation time related parameter, etc.) is transmitted to the OBU through signaling of the base station Or may be pre-stored in the OBU. A criterion that determines an MCS (e.g., a high efficiency MCS, a low efficiency MCS) (e.g., a mapping relationship between each parameter and an MCS) may be transmitted to the OBU via signaling of the base station or stored in the OBU in advance .

For example, if the speed of the vehicle (or OBU, UE) is greater than or equal to a predetermined threshold (e.g., the speed of the vehicle (or OBU, UE) is high) , A high order modulation scheme (e.g., 16QAM, 64QAM, etc.) and a high coding rate (e.g., 1/2, 2/3, 4/5, etc.) . If the speed of the vehicle (or OBU, UE) is less than a predetermined threshold (e.g., the speed of the vehicle (or OBU, UE) is low), then the OBU may use a low efficiency MCS (E.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), etc.) and a low coding rate (e.g., 1/12, 1/6, 1/3, etc.) . The preset threshold value used for judging the speed of the vehicle (or OBU, UE) may be transmitted to the OBU via signaling of the base station, or may be stored in advance in the OBU. A criterion that determines an MCS (e.g., a high efficiency MCS, a low efficiency MCS) (e.g., the vehicle speed and mapping relationship of the MCS) may be transmitted to the OBU via signaling of the base station, have.

If the density (or the size of the data) of the vehicle (or OBU, UE) is equal to or greater than a preset threshold value, the OBU performs a high-efficiency MCS (for example, a 16QAM, 64QAM, A high coding rate (for example, 1/2, 2/3, 4/5, etc.)) can be used. If the density (or the size of the data) of the vehicle (or OBU, UE) is less than a predetermined threshold value, then the OBU may be configured with a low efficiency MCS (e.g., low dimensional modulation schemes (e.g., BPSK, QPSK, Coding rate (e.g., 1/12, 1/6, 1/3, etc.)) can be used. A predetermined threshold value used for determining the density (or the size of data) of the vehicle (or OBU, UE) may be transmitted to the OBU via signaling of the base station, or may be stored in advance in the OBU. A criterion that determines an MCS (e.g., a high efficiency MCS, a low efficiency MCS) (e.g., a mapping between the density of the vehicle (or the size of the data) and the MCS) may be transmitted to the OBU via signaling of the base station, Or stored in the OBU in advance.

Also, if the coverage of the service (e.g., the reach of the service) is greater than or equal to a predetermined threshold (e.g., 500 m or 1 km), then the OBU may use a low efficiency MCS (e.g., (E.g., BPSK, QPSK, etc.) and a low coding rate (e.g., 1/12, 1/6, 1/3, etc.). When the coverage of the service (e.g., the reach of the service) is less than a predetermined threshold (e.g., 200m or 300m), the OBU may use a high efficiency MCS (e.g., a 16QAM, 64QAM Etc.) and a high coding rate (for example, 1/2, 2/3, 4/5, etc.)) can be used. The predetermined threshold value used for determining the coverage of the service (for example, the reach of the service) may be transmitted to the OBU via signaling of the base station, or may be stored in advance in the OBU. A criterion that determines an MCS (e.g., a high efficiency MCS, a low efficiency MCS) (e.g., a coverage of a service (e.g., a reach of a service) and a mapping relationship of an MCS) is transmitted to the OBU via signaling of the base station Or may be pre-stored in the OBU.

Next, a method of supporting autonomous driving in a vehicle communication network (for example, the vehicle communication network shown in Fig. 10) will be described. An RSU that supports autonomous driving may be an RSU installed at a traffic light at an intersection (or a pedestrian crossing), an RSU associated with a traffic light at an intersection (or pedestrian crossing), or an RSU installed in a structure (or building) . The RSU may also support a base station function or a relay function. In this case, the RSU can establish a direct communication resource pool and can support the connection function between the infrastructure network and the OBU.

The RSU may be configured to control a traffic signal (e.g., to control the operation timing of a traffic signal, to control traffic signals of a particular traffic signal) by exchanging information with a traffic control center (e.g., an intelligent transportation system Stop operation, etc.). The RSU may send control information / data to the OBU using resources (e.g., wireless interface (e.g., Uu interface) between the base station and the UE) for direct communication (e.g., D2D communication, vehicle communication) .

The RSU can obtain the vehicle-related parameters from the OBU, or can estimate the vehicle-related parameters using a separate sensor, imaging device, or the like. In addition, the RSU can acquire vehicle-related parameters from other RSUs installed or associated with traffic lights at adjacent intersections (or pedestrian crossings). The RSU can control the traffic signal in consideration of the vehicle-related parameters.

The RSU can send a control message to the OBU indicating a deceleration, acceleration stop, stop, etc. before the stop signal of the traffic light is turned on (for example, before a preset reference time). In addition, the RSU may send a control message to the OBU indicating the operating time of the stop signal of the traffic light. Here, the operation time may be the time remaining until the stop signal is turned on or the exact time at which the stop signal is operated. When the stop signal related control message is received, the OBU can control the vehicle to decelerate or stop based on the speed of the vehicle, the road conditions (e.g., road related parameters), the distance to the ahead vehicle, and the like. In particular, a vehicle that supports autonomous driving can efficiently perform an autonomous driving function based on information obtained through direct communication with the RSU, instead of information collected from sensors used for autonomous driving. For example, the RSU may notify the driver of the operation (or the end of the operation) of a signal indicating the start, stop, straight ahead, left turn, right turn, etc. of the traffic light for the pedestrian, The efficiency of the autonomous drive function can be improved by transmitting the control signal to the OBU that supports the autonomous drive function.

The RSU may be connected to a road (e.g., India) using resources (e.g., U1 interface) between the base station and the UE for direct communication (e.g., D2D communication, vehicular communication) (I.e., user information of the UE) from the located UE, and can transmit the obtained user information to the OBU located on the road. The user information may be safety related information (e.g., information for vehicle accident prevention). For example, the user information may be a location, a speed, a type (e.g., a disabled person, a child, etc.) of a user (e.g., a pedestrian), a walking aid, a vehicle (e.g., a bicycle)

Alternatively, the RSU may obtain the user information via other methods instead of the direct communication, and may transmit the obtained user information to the OBU located on the road. For example, the RSU may obtain user information based on image information obtained from a video device (e.g., CCTV, camera, etc.), or may acquire user information via eye communication. Here, the line-of-sight communication may be a point-to-point direct communication that obtains information from a counterpart communication node by transmitting a radio wave (or a beam) having strong linearity to the counterpart communication node. According to the line-of-sight communication, communication with the counterpart communication node can be performed even when the identifier information (e.g., telephone number, source ID, destination ID, etc.) of the counterpart communication node is unknown.

The RSU can obtain vehicle information (i.e., vehicle information with the OBU installed) from the OBU located on the road, and can transmit the acquired vehicle information to the UE located on the road (e.g., India). Such an operation can prevent a vehicle accident. Here, the vehicle information may be a speed, a moving route, a type, etc. of the vehicle.

On the other hand, when the presence of a pedestrian is confirmed through a separate sensor, a video device (for example, CCTV, camera, etc.), the RSU transmits the confirmed pedestrian-related information (for example, user information) To the OBU in a broadcast manner. Alternatively, if the presence of a pedestrian is identified, the RSU can request user information from the pedestrian's UE and obtain user information from the UE in response to the request. Regardless of the request of the user information, the UE may transmit the user information to the RSU if the existence of the RSU is confirmed. The RSU can generate an alarm message for prevention of a vehicle accident in consideration of the obtained user information, and can transmit the generated alarm message to the OBU located on the road.

Meanwhile, the user information (or vehicle information) described above may be transmitted to the RSU that performs monitoring for the road related parameters, and the RSU that supports the relay function outside the coverage of the communication network.

Next, a communication method performed by the communication node in the vehicle communication network will be described.

11 is a flow chart illustrating an embodiment of a communication method performed by a communication node in a vehicle communication network.

Referring to FIG. 11, each of the base station 1 and the base station 2 may be a base station 821, 822 or an RSU 831, 832 shown in FIG. Each of OBU1 and OBU2 may be a UE 841, 842 or an OBU 851, 852 shown in Fig. For example, the transmission / reception of control information / data between the base station and the OBU can be performed through the Uu interface. The transmission / reception of control information / data between the OBUs can be performed through the PC5 interface. Each of the base station 1, the base station 2, the OBU1 and the OBU2 may have the same or similar structure as the communication node 200 shown in Fig. The operator of the base station 1 may be the same as or different from the operator of the base station 2. The operator to which OBU1 is subscribed may be the same as or different from the operator to which OBU2 is subscribed.

On the other hand, the base stations can directly negotiate the communication resource pool so that direct communication is performed irrespective of the status of OBUs (e.g., RRC connection state, RRC idle state). The configuration information of the direct communication resource pool may include system bandwidth, center frequency, frequency resource information, time resource information, period (or interval) of resources, and the like. The direct communication resource pool can be classified into a transmission resource pool, a reception resource pool, and the like. Also, the direct communication resource pool can be classified into a resource pool for a discovery operation, a resource pool for data communication, and the like.

A connection setting operation (e.g., a bearer) between the base station 1 and the OBU 1 may be performed (S1100). When the connection setting operation is completed, the OBU1 can operate in the RRC connection state. In step S1100, the base station 1 can allocate resources for direct communication to the OBU1 based on the mode 1 scheme. For example, the base station 1 may select a resource for direct communication in a direct communication resource pool (e.g., a direct communication resource pool negotiated in advance at the base stations) and may transmit the selected resource information to the OBU 1. The OBU 1 can acquire the resource information from the base station 1 and can confirm the resources for direct communication based on the acquired resource information.

The OBU 2 can operate in the RRC idle state without establishing a connection with the base station 2. For example, the OBU 2 may operate in a camped state at the base station 2. The resources for the direct communication of the OBU2 can be set based on the mode 2 scheme. For example, the base station 2 may transmit system information including configuration information of a direct communication resource pool (e.g., a direct communication resource pool negotiated in advance at the base stations) (S1101). The OBU 2 can acquire the system information from the base station 2 and can confirm the configuration information of the communication resource pool directly from the system information. Here, although the step S1101 is described as being performed after the step S1100, the order of execution of the step S1101 may not be limited to the above-described contents. For example, step S1101 may be performed simultaneously with step S1100 or may be performed before step S1100.

Thereafter, the OBU1 can transmit control information (or data) to the OBU2 using direct communication (S1102). Transmission of the control information (or data) can be performed even when the state of the OBU1 (for example, the RRC connection state) is different from the state of the OBU2 (for example, the RRC idle state). For example, the OBU 1 can transmit scheduling information of control information (or data) using a separate physical layer control channel for direct communication (for example, resources for transmission of scheduling information). The scheduling information may include resource allocation information (e.g., frequency resource information, time resource information), MCS information, and the like. Here, the MCS information may be set based on at least one of the road related parameter, the vehicle related parameter, the service related parameter, the message related parameter, and the operation time related parameter described above.

After the scheduling information is transmitted, the OBU 1 can transmit the control information (or data) to which the MCS indicated by the scheduling information is applied, through the resource indicated by the scheduling information. On the other hand, the OBU 2 can acquire the scheduling information from the OBU 1 by monitoring the resources belonging to the direct communication resource pool. The OBU 2 can acquire control information (or data) from the OBU 1 through the resource indicated by the scheduling information and demodulate / decode the control information (or data) on the basis of the MCS indicated by the scheduling information Can be performed.

The OBU2 can randomly select a resource from the direct communication resource pool obtained in step S1101, and can transmit control information (or data) to the OBU1 using the selected resource (S1103). The OBU 1 can directly confirm the configuration information of the communication resource pool (for example, the direct communication resource pool negotiated in advance by the base stations) from the system information transmitted from the base station 1 or a separate control message. The OBU 1 can receive control information (or data) from the OBU 2 by performing monitoring on the resources belonging to the confirmed direct communication resource pool. Also, the OBU 1 can acquire the scheduling information from the adjacent communication node, and can receive the control information (or data) from the OBU 2 through the resource indicated by the scheduling information.

On the other hand, if there is no resource to be used for transmission of the control information (or data) (for example, the resource allocated in step S1100 can not be used), the OBU1 requests resource allocation For example, a control message requesting resource allocation may be transmitted (S1104). For example, the OBU1 may request the base station 1 to allocate resources based on a random access procedure, a scheduling request procedure of a physical uplink control channel (PUCCH), or a BSR procedure. A separate resource for OBU1 (e.g., a resource allocated based on a random access procedure, a resource allocated based on a PUCCH, a BSR procedure, etc.) to minimize the impact on other communication nodes receiving service from the base station 1, Can be set. In particular, a separate PUCCH for direct communication may be established.

When the base station 1 receives a resource allocation request from the OBU1, the base station 1 can allocate resources for direct communication (S1105). For example, the base station 1 may select a resource for direct communication in a direct communication resource pool (e.g., a direct communication resource pool negotiated in advance at the base stations) and may transmit the selected resource information to the OBU 1. The resource for the direct communication allocated in step S1105 may be different from the resource for the direct communication allocated in step S1100. If a resource for direct communication is allocated, the OBU1 may transmit control information (or data) to another communication node (e.g., OBU2) using the allocated resource (S1106). Alternatively, if the request procedure of the resource allocation (i.e., step S1104 and step S1105) is not performed, the OBU1 can randomly select a resource in the direct communication resource pool obtained through the system information or the message to the separate agent, (Or data) to another communication node (e.g., OBU2) using the resources. The OBU2 can receive control information (or data) from the OBU1 by monitoring the resources belonging to the direct communication resource pool acquired in step S1101.

On the other hand, the OBU2 in the RRC idle state can perform the connection establishment operation with the base station 2 when necessary (S1107). When the connection setting operation is completed, the OBU2 can operate in the RRC connection state. In step S1107, the base station 2 can allocate the resources for direct communication to the OBU2 based on the mode 1 scheme. For example, base station 2 may select resources for direct communication in a direct communication resource pool (e.g., a direct communication resource pool negotiated in advance at base stations) and may transmit the selected resource information to OBU2. The OBU 2 can acquire the resource information from the base station 2 and can confirm the resources for direct communication based on the acquired resource information. Thereafter, the OBU2 can transmit control information (or data) to the OBU1 using the resources allocated from the base station 2 (S1108). The OBU 1 can receive control information (or data) from the OBU 2 by monitoring the resources belonging to the direct communication resource pool obtained through system information or a separate control message.

On the other hand, if the direct communication service based on the mode 1 scheme is terminated, the OBU 1 can transmit a message to the base station 1 indicating the termination of the direct communication service based on the mode 1 scheme (S1109). If a message indicating the termination of the direct communication service based on the mode 1 scheme is received, the base station 1 may perform a resource release operation or a connection release operation of direct communication (S1110). When the resource release operation is performed, the base station 1 can release the resources set for the direct communication of the OBU1. In this case, the OBU1 may not perform the direct communication function, and may operate in the RRC connection state. When the disconnection operation is performed, the base station 1 can release the resources set for the direct communication of the OBU1 and disconnect the connection with the OBU1. In this case, the base station 1 may send a reconfiguration message to the OBU 1 informing of the release of the connection. The reset message may include configuration information of a direct communication resource pool (e.g., a direct communication resource pool negotiated in advance at the base stations) according to the mode 2 scheme. Here, the OBU1 can operate in the RRC idle state, and can directly confirm the configuration information of the communication resource pool by receiving the reset message from the base station 1. [

Thereafter, when control information (or data) to be transmitted through the direct communication method is generated, the OBU1 can randomly select the resources from the system information or the direct communication resource pool obtained through step S1110, and using the selected resources Control information (or data) to the OBU2 (S1111). The OBU2 can receive control information (or data) from the OBU1 by performing monitoring on the resources belonging to the direct communication resource pool obtained through step S1101.

On the other hand, if there is no resource to be used for transmission of the control information (or data) (for example, the resource allocated in step S1107 can not be used), the OBU2 requests the base station 2 to allocate resources For example, a control message requesting resource allocation may be transmitted (S1112). Here, step S1112 may be the same as or similar to step S1104 described above. The OBU 2 can acquire resources for communication directly from the base station 2 in response to a request for resource allocation, and can transmit control information (or data) using the acquired resources.

Steps S1100 to S1112 described above may not be performed sequentially. (E.g., steps S1100 and S1107 for a connection establishment operation, steps S1104, S1105, and S1112 for a resource allocation request), control information / data transmission Steps S1102, S1103, S1106, SS1108, and S1111, steps S1109 and S1110 for terminating direct communication, and the like may be selectively performed.

Next, a communication method based on visual communication (or image information) in a vehicle communication network will be described.

12 is a flowchart showing an embodiment of a communication method based on a visual communication in a vehicle communication network.

Referring to Fig. 12, the vehicle communication network may include a preceding vehicle, a trailing vehicle, and the like. Each of the preceding vehicle and the following vehicle may include OBUs 851, 852 or UEs 841, 842 shown in Fig. Each of the preceding vehicle and the following vehicle may include an imaging device. The trailing vehicle can acquire the image of the preceding vehicle using the image device and analyze the acquired image to estimate the information (e.g., the type of vehicle, number, etc.) of the preceding vehicle (S1200).

The trailing vehicle can transmit a message including the information of the preceding vehicle, the information of the trailing vehicle (e.g., the type and number of the vehicle), the identifier of the trailing vehicle, and the like to the preceding vehicle (S1201). In this case, the trailing vehicle can transmit the message including the information of the preceding vehicle, the information of the trailing vehicle, the identifier of the trailing vehicle, and the like to the preceding vehicle by using the direct communication or the sight communication. When direct communication is used, the message may be transmitted in a broadcast or multicast manner. When gaze communication is used, the message can be transmitted over radio waves (or beams) with strong straightness.

The preceding vehicle can receive the message from the following vehicle, and can confirm the information of the preceding vehicle, the information of the following vehicle, the identifier of the following vehicle, and the like included in the message. If the reliability of the message received from the trailing vehicle (or the information contained in the message) meets a predetermined criterion (or if necessary), the preceding vehicle may transmit a message containing its identifier to the trailing vehicle S1202). When the steps S1201 and S1202 are performed, a joint / join related operation of the group, a state (e.g., abnormal state, etc.) reporting operation of each vehicle, and the like may be performed.

In the above-described steps S1200 to S1202, the preceding vehicle can perform the role of the trailing vehicle, and the trailing vehicle can perform the role of the preceding vehicle. For example, steps S1200 and S1201 may be performed by the preceding vehicle, and step S1202 may be performed by the trailing vehicle.

Thereafter, direct communication (e.g., point-to-point direct communication) between the preceding vehicle and the following vehicle may be performed (S1203). When direct communication is performed, joint / withdrawal-related operations of the group, status of each vehicle (for example, abnormal status, etc.), and the like may be performed.

Meanwhile, in order to support vehicle communication, a base station (or an RSU) can perform downlink transmission in a broadcast scheme or a multicast scheme. For example, the base station may transmit information obtained from an OBU (or UE) or a communication node belonging to a network (for example, a communication node belonging to a higher layer) to a broadcast resource (or a multicast resource) Lt; / RTI > When a broadcast scheme is used, the base station transmits the information obtained from the OBU or the network through a resource (hereinafter referred to as "MBSFN resource") set for MBSFN (MBMS (single- Lt; / RTI >

The base station can broadcast the control information / data related to the vehicle communication using the MBSFN resource according to the MBMS procedure. In this case, the base station can set up a separate MBSFN subframe supporting vehicle communication, and can transmit vehicle communication related control information / data using a separate MBSFN subframe. In addition, the base station may transmit information obtained from the OBU to a communication node (e.g., a server supporting a vehicle communication, an MBMS coordination entity (MCE), etc.) belonging to the network. The base station can broadcast the control information / data related to the vehicle communication using the MBSFN sub-frame according to the control of the communication node (e.g., server supporting the vehicle communication, MCE, etc.) belonging to the network.

On the other hand, when a multicast scheme is used, the base station can transmit control information of the physical layer using a separate group scheduling identifier (e.g., V2X-RNTI (radio network temporary identifier)) set for vehicle communication, It may transmit information using a physical downlink shared channel (PDSCH) that is addressed (e.g., addressed) by control information of the physical layer. In particular, the base station transmits information obtained from OBUs belonging to a specific group to a communication node belonging to the network (for example, a server supporting a vehicle communication, an MCE, etc.) And a group scheduling identifier to transmit to a specific group in a multicast manner.

Here, when the vehicle communication-related control information / data is received from the OBU through the resource included in the vehicle communication resource pool or the uplink resource, the base station can confirm the group to which the OBU that transmitted the vehicle communication-related control information / data belongs . In this case, the base station determines to transmit the obtained vehicle communication-related control information / data to the OBUs belonging to the identified group regardless of transmitting the vehicle communication-related control information / data acquired from the OBU to the communication node belonging to the network . For example, the base station may send vehicle-communication related control information (e.g., V2X-RNTI) to OBUs belonging to the group using a group identifier (e.g., a destination identifier / address for vehicle communication) or a group scheduling identifier / Data can be transmitted. In this case, the vehicle communication-related control information / data may be transmitted in a multicast manner via downlink resources.

In the transmission procedure of the vehicle communication related control information / data described above, the OBU can transmit the vehicle communication related control information / data using the PC5 interface or the Uu interface, and the base station transmits the vehicle communication related control information / Data can be transmitted.

Meanwhile, in order to support D2D communication, vehicle communication, MTC, M2M-based communication, and IoT-based communication in the LTE / LTE-A system, message transmission can be performed in PRB (physical resource block) units. Here, the message may include control information, data, and the like for direct communication. The message transmission via the PRB can be performed as follows.

13 is a timing diagram showing an embodiment of a message transmission method over a PRB.

13, the control channel may be a physical downlink control channel (PDCCH), a physical sidelink control channel (PSCCH), and the like. The data channel may be a PDSCH, a physical sidelink shared channel (PSSCH), or the like. The PRB may be set according to the scheduling period. Further, the PRB can be set based on a frequency hopping scheme. A base station (e.g., a block supporting the scheduling function included in the base station) may generate scheduling information including PRB allocation information, MCS information, and the like. The base station can transmit the scheduling information through the control channel. The OBU can receive the scheduling information from the base station through the control channel and can transmit the data to which the MCS indicated by the scheduling information is applied through the PRB indicated by the scheduling information.

Alternatively, the OBU can randomly select the PRB from the pre-acquired direct communication resource pool from the base station and transmit the data through the selected PRB. In this case, the base station may not transmit the scheduling information, and the OBU may directly control the PRB to be selected randomly in the communication resource pool. Also, the base station can control the OBU (or UE, group) set in advance to select the PRB based on the scheduling pattern.

Next, a method for repeatedly transmitting data in direct communication will be described. Here, the repetitive transmission may include retransmission, transmission based on hybrid automatic repeat request (HARQ), and the like. The data channel of the physical layer for direct communication may be the PUSCH, PSSCH of the LTE / LTE-A system, a separate data channel set for direct communication, and so on. The control channel of the physical layer for direct communication may be PDCCH, enhanced PDCCH (ePDCCH), PUCCH, PSCCH of the LTE / LTE-A system, or a separate control channel set for direct communication.

In order to extend service coverage in direct communication, improve transmission reliability, etc., the message may be transmitted continuously or discretely (e.g., in a transmission period, or in a transmission window, The PRB assigned by the base station, the PRB selected by the OBU). Here, the message may include control information, data, and the like for direct communication. The transmission period may be a time interval set on the time axis and may be set separately for direct communication. The transmission period can be signaled to the OBU via a separate control message. For example, the transmission period may be the transmission period shown in FIG.

The control information for repeated transmission of data may include information on the number of repetition transmissions, redundancy version (RV), MCS information, repetition transmission time, resource allocation information (e.g., system bandwidth, frequency resource information , Time resource information (e.g., subframe index, slot index, symbol index, etc.)), and the like. Control information for repeated transmission may be transmitted in an explicit signaling manner or implicitly. Alternatively, the control information for repeated transmission may be set by a communication node performing repetitive transmission of data. Here, the communication node may be a base station, a UE, an RSU, an OBU, or the like.

Explicit Signaling  Method for repeated transmission of data based on method

The transmitting communication node may transmit control information for repeated transmission to the receiving communication node. Alternatively, the control information for repeated transmission can be preset in the transmitting communication node and the receiving communication node. Therefore, the transmitting communication node can perform repeated transmission of data based on the control information for repeated transmission. The receiving communication node can receive the repeatedly transmitted data based on the control information for the repeated transmission and can perform the demodulation / decoding operation on the received data. In addition, the receiving communication node may send a feedback message (e.g., an acknowledgment message) to the transmitting communication node indicating that the data has been successfully received.

Implicit Signaling  Method for repeated transmission of data based on method

The number of iterations of data transmission depends on the capability of the communication node, the location of the communication node, the MCS information, the resource allocation information, the attributes of the service (for example, whether cyclic data is generated, Transmission method, etc.), coverage of the service (e.g., reach distance), area of service, size of data, and the like. That is, the mapping relationship between the number of repetitive transmissions and other information can be preset in the network, or can be transmitted to the communication node through separate control signaling.

For example, MCS index 1 may be mapped to an iterative transmission number of 2, MCS index 2 may be mapped to an iterative transmission number of 4, and MCS index 3 may be mapped to an iterative transmission number of 6. Therefore, the transmitting communication node can select the number of repeated transmission mapped to the MCS index, and can repeatedly transmit data according to the selected number of repeated transmission. The receiving communication node can confirm the number of repetitive transmissions mapped to the MCS index and can receive repeatedly transmitted data according to the number of repetitive transmissions.

When the data transmission scheme is classified into a transmission scheme through a path (or a logical channel) of a user plane and a transmission scheme through a path of a control plane, the number of repetitive transmissions mapped to the transmission scheme through the path of the user plane is May be different from the number of repetitive transmissions mapped to the transmission scheme through the path of the control plane. Alternatively, the number of repeated transmissions may be set differently depending on whether piggyback transmission is performed or not.

In addition, the mapping relationship between the range of the data size and the number of repeated transmission can be set in advance, and the number of repeated transmission can be set according to the size range of the data to which the current data belongs.

Method for repeated transmission of data based on setting of communication node

The minimum number of repeated transmissions and the maximum number of repeated transmissions may be preset in the network or may be transmitted to the communication node via separate control signaling. The transmitting communication node can set the number of repeated transmissions to a multiple of the minimum number of repeated transmissions. Here, the set number of repetitive transmissions may be less than the maximum number of repetitive transmissions. The number of repetitive transmissions can be variably set according to the capacity of the communication node, the location of the communication node, the MCS information, the resource allocation information, the attribute of the service, the coverage of the service, the area of the service,

Fig. 14 is a timing chart showing an embodiment of a repetitive data transmission method. Fig.

Referring to FIG. 14, each of the transmitting communication node and the receiving communication node may be the above-described base station, RSU, UE, OBU, and the like. T1 can indicate the first data to be transmitted, T2 can indicate the second repeatedly transmitted data, T3 can indicate the third repeatedly transmitted data, and T4 can indicate the fourth repeatedly transmitted data T5 may indicate the fifth repeatedly transmitted data, and T6 may indicate the sixth repeatedly transmitted data. The scheduling information (e.g., resource allocation information, MCS information, etc.) of the T1 may be set by the communication node or may be signaled to the communication node via a separate control message. When the scheduling information of T1 is determined, the scheduling information of T2 (or T3, T4, T5, T6, etc.) after T1 can be determined based on the scheduling information of T1.

 The number of times of repeated transmission of data can be determined based on the above-described method. (Or condition, rule) of repeated transmission, the number of repeated transmission, the number of repeated transmission, the number of repeated transmission, the mapping relation between the number of repeated transmission and the other information, the data transmission period, Scheduling information and the like can be defined as common parameters in the network and can be set in units of a specific service area (for example, service area, cell, coverage, etc.) May be signaled to the communication node via a dedicated control message, a MAC control protocol data unit (PDU), or a control field of the physical layer.

The transmitting communication node can repeatedly transmit data according to the number of repetitive transmissions in the transmission period. The receiving communication node may receive data from the transmitting communication node and perform demodulation / decoding on the received data by performing soft combining based on the minimum number of repeated transmissions in the transmission period. On the other hand, the receiving communication node can perform demodulation / decoding on data using the iterative reception technique even when the number of repeated transmission is unknown. Here, the soft combining technique may include a chase combining technique, an incremental redundancy (IR) technique, and the like. Also, techniques for combining repeatedly transmitted data (or bits, symbols) (e.g., patterns of different parity bits or transmission techniques of RVs of CRC (cyclic redundancy check)) to improve reception performance, Can be used.

The method of repeated transmission of data in case 1 may be as follows.

In Case 1, the number of repetitive transmissions may be six. The transmitting communication node can repeatedly transmit data (T1, T2, T3, T4, T5, T6) six times in the transmission period. The receiving communication node can receive data (T1, T2, T3, T4, T5, T6) from the transmitting communication node and perform soft combining on the basis of the minimum number of repeated transmissions, , T4, T5, and T6).

If the minimum number of repeated transmissions is two, the receiving communication node can perform soft combining on two data units. The receiving communication node can verify the CRC by performing soft combining on each of "T1, T2", "T3, T4" and "T5, T6". If the CRC result for the two data is "check good" (e.g., if the channel condition meets a predetermined criterion), then the data may be sent to the upper layer.

On the other hand, if the CRC result for the two data is not "check good" (e.g., the channel condition does not meet the predetermined criteria), then the receiving communication node will receive soft combining results of "T1, Soft combination of "T3, T4" soft combining result can be performed, and soft combination result of "T3, T4" and "T5, T6" soft combining result can be performed . If the CRC result for the four data items is "check good ", the corresponding data can be transmitted to the upper layer.

On the other hand, if the CRC result for the four data items is not "check good ", the receiving communication node transmits the soft combining result of" T1, T2 ", the soft combining result of" T3, T4 " Soft combining can be performed on the soft combining result. If the CRC result for the six data items is "check good ", the corresponding data can be transmitted to the upper layer. On the other hand, if the CRC result for the six pieces of data is not "check good ", a message indicating failure in reception may be transmitted to the upper layer.

In cases 2 and 6, the repetitive transmission method of data may be as follows.

In cases 2 and 6, the number of repeated transmissions may be four. The transmitting communication node can repeatedly transmit data (T1, T2, T3, T4) four times in the transmission period. The receiving communication node can receive data (T1, T2, T3, T4) from the transmitting communication node and perform soft combining on the basis of the minimum number of repeated transmissions to obtain the received data (T1, T2, T3, T4) And perform demodulation / decoding on the data.

If the minimum number of repeated transmissions is two, the receiving communication node can perform soft combining on two data units. The receiving communication node can verify the CRC by performing soft combining on each of "T1, T2" and "T3, T4 ". If the CRC result for the two pieces of data is "check good ", the corresponding data can be transmitted to the upper layer.

On the other hand, if the CRC result for the two data is not "check good", the receiving communication node performs soft combining on the soft combining result of "T1, T2" and the soft combining result of "T3, T4" can do. If the CRC result for the four data items is "check good ", the corresponding data can be transmitted to the upper layer. On the other hand, if the CRC result for the four pieces of data is not "check good ", a message indicating failure in reception may be transmitted to the upper layer.

In cases 3, 4 and 5, the repetitive transmission method of data may be as follows.

In cases 3, 4 and 5, the number of repetitive transmissions may be two. The transmitting communication node can repeatedly transmit the data (T1, T2) twice in the transmission period. The receiving communication node can receive data (T1, T2) from the transmitting communication node and performs demodulation / decoding on the received data (T1, T2) by performing soft combining on the basis of the minimum number of repeated transmissions . If the minimum number of repeated transmissions is two, the receiving communication node can perform soft combining on two data units. The receiving communication node can verify the CRC by performing soft combining on "T1, T2 ". If the CRC result for the two pieces of data is "check good ", the corresponding data can be transmitted to the upper layer. On the other hand, if the CRC result for the two data is not "check good ", a message indicating failure in reception may be transmitted to the upper layer.

The methods according to the present invention can be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer readable medium may be those specially designed and constructed for the present invention or may be available to those skilled in the computer software.

Examples of computer readable media include hardware devices that are specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

Claims (20)

A method of operating a first user equipment (UE) supporting direct communication in a communication network,
Obtaining scheduling information set for the direct communication from a first base station to which the first UE belongs;
Checking modulation and coding scheme (MCS) information and radio resource information included in the scheduling information; And
And transmitting a first message to which the MCS indicated by the MCS information is applied, to a second UE via a radio resource indicated by the radio resource information. The method according to claim 1,
Wherein the state of the first UE is a radio resource control (RRC) connected state or an RRC idle state. The method according to claim 1,
Wherein the scheduling information is shared between the first base station and a second base station to which the second UE belongs. The method according to claim 1,
The radio resource indicated by the radio resource information is set based on the speed of the vehicle where the first UE is located, the density of the vehicle in the zone to which the first UE belongs, or the service coverage of the direct communication , The first UE operating method. The method according to claim 1,
When the mode 1 scheme is used, the radio resource information indicates a radio resource selected by the first base station from the direct communication resource pool, and when the mode 2 scheme is used, Direct communication resource pool. ≪ Desc / Clms Page number 17 > The method according to claim 1,
Wherein the MCS information indicates an MCS index or an MCS range set by the first base station. The method according to claim 1,
Wherein the MCS indicated by the MCS information is set based on the speed of the vehicle in which the first UE is located, the density of the vehicle in the zone to which the first UE belongs or the service coverage of the direct communication. The method according to claim 1,
Wherein communication between the first base station and the first UE is performed via a Uu interface and the direct communication between the first UE and the second UE is performed via a PC5 interface. The method according to claim 1,
Wherein the first base station is a first RSU (roadside unit) belonging to a vehicle communication network, the first UE is a first OBU (onboard unit) belonging to the vehicle communication network, And the second OBU. The method according to claim 1,
The method of claim 1,
Obtaining a communication resource pool directly from the first base station;
Performing a monitoring operation on radio resources belonging to the direct communication resource pool; And
Further comprising receiving a second message from the second UE based on the monitoring operation. The method according to claim 1,
The method of claim 1,
Requesting the first base station to allocate additional radio resources for the direct communication if the radio resource can not be used;
Obtaining additional radio resource information from the first base station; And
And sending a third message to the second UE via the additional radio resource indicated by the additional radio resource information. The method of claim 11,
Wherein the first UE requests allocation of the additional radio resource to the first base station based on a random access procedure, a scheduling request procedure of a physical uplink control channel (PUCCH), or a buffer status report (BSR) A method of operating a first UE. The method of claim 11,
Wherein the additional radio resource is selected from radio resources other than radio resources used for transmission of the first message among direct communication resource pools. A method of operating a first user equipment (UE) supporting direct communication in a communication network,
Sending a first message requesting termination of the direct communication to a first base station to which the first UE belongs when the direct communication between the first UE and the second UE is terminated; And
Performing a release operation of a radio resource or a release operation of a radio resource control (RRC) connection with the first base station to terminate the direct communication,
Wherein the first UE operates in an RRC connection state when the radio resource release operation is performed and the first UE operates in an RRC idle state when the RRC connection release operation is performed. 1 UE operating method. 15. The method of claim 14,
The method of claim 1,
Requesting the first base station to allocate radio resources for the direct communication when the direct communication between the first UE and the second UE is requested in an RRC connected state;
Obtaining radio resource information from the first base station; And
And sending a second message to the second UE via the radio resource indicated by the radio resource information. 15. The method of claim 14,
The method of claim 1,
Selecting a radio resource from a direct communication resource pool obtained from the base station if the direct communication between the first UE and the second UE is requested in an RRC idle state; And
And sending a third message to the second UE over the selected radio resource. 18. The method of claim 16,
Wherein the direct communication resource pool is set based on the speed of the vehicle in which the first UE is located, the density of the vehicle in the zone to which the first UE belongs, or the service coverage of the direct communication. How it works. 18. The method of claim 16,
Wherein the direct communication radio resource pool is shared between the first base station and a second base station to which the second UE belongs. 18. The method of claim 16,
Wherein a modulation and coding scheme (MCS) applied to the third message is set based on the speed of the vehicle in which the first UE is located, the density of the vehicle in the zone to which the first UE belongs or the service coverage of the direct communication. 1 UE operating method. 15. The method of claim 14,
Wherein the first base station is a first RSU (roadside unit) belonging to a vehicle communication network, the first UE is a first OBU (onboard unit) belonging to the vehicle communication network, And the second OBU.

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