KR20200127862A - Method and apparatus for data transmission in wireless local access network - Google Patents

Abstract

According to the present invention, an operation method of a first communication node in a communication network comprises the steps of: checking the number of second communication nodes receiving messages in a first receiving mode and the number of third communication nodes receiving messages in a second receiving mode; determining a transmission mode for transmitting a wireless access in vehicular environments service advertisement (WSA) message based on the checked numbers; determining a transmission period for transmitting the WSA message based on the transmission mode; and transmitting the WSA message based on the transmission mode and the transmission period. A protocol used in the first receiving mode and a protocol used in the second receiving mode are different from each other. Therefore, the performance of the communication network can be improved.

Description

Data transmission method and device in wireless LAN {METHOD AND APPARATUS FOR DATA TRANSMISSION IN WIRELESS LOCAL ACCESS NETWORK}

The present invention relates to a method and apparatus for transmitting data in a wireless LAN network, and more particularly, to a method of operating a communication node transmitting a wireless access in vehicular environments service advertisement (WSA) message.

Recently, as the spread of mobile devices expands, a wireless LAN technology capable of providing fast wireless Internet services to them is in the spotlight. Wireless LAN technology is a technology that enables mobile devices such as smart phones, smart pads, laptop computers, portable multimedia players, and embedded devices to wirelessly access the Internet based on wireless communication technology in a short distance.

The wireless LAN technology in the early days was based on IEEE (Institute of Electrical and Electronics Engineers) 802.11, using 2.4GHz frequency to support 1~2Mbps speed through frequency hopping, spreading, and infrared communication. (Orthogonal Frequency Division Multiplex) can be applied to support a maximum speed of 54Mbps. In addition, IEEE 802.11 improves QoS (Quality for Service), access point (AP) protocol compatibility, security enhancement, radio resource measurement, and wireless access vehicular for vehicle environments. environment), fast roaming, mesh network, interworking with external network, wireless network management, etc.

Among IEEE 802.11, IEEE 802.11b supports a communication speed of up to 11Mbps while using a frequency of the 2.4GHz band. IEEE 802.11a, commercialized after IEEE 802.11b, has reduced the effect of interference compared to the frequency of the 2.4GHz band, which is quite congested by using the frequency of the 5GHz band instead of the 2.4GHz band, and uses OFDM technology to maximize the communication speed. Improved to 54Mbps. However, IEEE 802.11a has a short communication distance compared to IEEE 802.11b. And IEEE 802.11g, like IEEE 802.11b, implements a communication speed of up to 54Mbps using a frequency of the 2.4GHz band, and has received considerable attention because it satisfies backward compatibility. Have the upper hand.

In addition, there is IEEE 802.11n as a technical standard established to overcome the limitation on communication speed which has been pointed out as a vulnerability in wireless LAN. IEEE 802.11n aims to increase the speed and reliability of the network and extend the operating distance of the wireless network. More specifically, IEEE 802.11n supports high throughput (HT) with a data processing speed of 540 Mbps or more, and uses multiple antennas at both ends of the transmitter and receiver to minimize transmission errors and optimize the data rate. It is based on MIMO (Multiple Inputs and Multiple Outputs) technology. In addition, this standard not only uses a coding scheme for transmitting multiple duplicate copies to increase data reliability, but may also use Orthogonal Frequency Division Multiplex (OFDM) to increase speed.

As the spread of wireless LANs becomes active and applications using them become diversified, in recent years, there is a need for a new wireless LAN system to support a higher throughput (Very High Throughput, VHT) than the data processing speed supported by IEEE 802.11n. This is emerging. Among them, IEEE 802.11ac supports a wide bandwidth (80MHz~160MHz) at 5GHz frequency. The IEEE 802.11ac standard is defined only in the 5GHz band, but for backward compatibility with existing 2.4GHz band products, the initial 11ac chipsets will also support operation in the 2.4GHz band. At this time, 802.11ac supports bandwidth from 2.4GHz up to 40MHz. In theory, according to this standard, the wireless LAN speed of multiple terminals is at least 1 Gbps and the maximum single link speed is at least 500 Mbps. This is achieved by extending the concept of the air interface adopted by 802.11n, such as a wider radio frequency bandwidth (up to 160 MHz), more MIMO spatial streams (up to 8), multi-user MIMO, and high density modulation (up to 256 QAM). In addition, there is IEEE 802.11ad as a method of transmitting data using a 60GHz band instead of the existing 2.5GHz/5GHz. IEEE 802.11ad is a transmission standard that provides a maximum speed of 7Gbps using beamforming technology, and is suitable for high bit rate video streaming such as large amounts of data or uncompressed HD video. However, the 60GHz frequency band has a disadvantage that it is difficult to pass through obstacles and can only be used between devices in a short distance.

Meanwhile, IEEE 802.11p is a standard developed for intelligent transport system (ITS) communication. The IEEE 802.11p physical layer uses the IEEE 802.11a physical layer, and the IEEE 802.11p MAC layer employs the IEEE 802.11e Enhanced Distributed Channel Access (EDCA). Furthermore, IEEE 802.11bd, an enhanced version of IEEE 802.11p, is being developed as a communication standard for intelligent traffic information systems. Therefore, a terminal using IEEE 802.11p and a terminal using IEEE 802.11bd can coexist on a wireless LAN network. In the future, when IEEE 802.11bd standardization is completed and a terminal using IEEE 802.11bd is mass-produced and used, various problems may occur in relation to a terminal using the IEEE 802.11p that is already used.

An object of the present invention to solve the above problems is to solve a problem caused by coexistence of terminals using IEEE 802.11p and terminals using IEEE 802.11bd in a wireless LAN network.

In order to achieve the above object, a method of operating a first communication node in a communication network according to an embodiment of the present invention includes the number and number of second communication nodes receiving a message in a first reception mode. 2 Checking the number of third communication nodes receiving the message in the reception mode, determining a transmission mode for transmitting a Wireless access in vehicular environments Service Advertisement (WSA) message based on the checked number, the transmission Determining a transmission period for transmitting the WSA message based on a mode, and transmitting the WSA message based on the transmission mode and the transmission period, and the protocol used for the first reception mode (protocol ) And the protocol used in the second reception mode are different from each other.

Here, the WSA message may further include service information for the second communication nodes or service information for the third communication nodes.

Here, when only the second communication nodes exist in the communication network, the transmission mode is determined as a first transmission mode, and when only the third communication nodes exist in the communication network, the transmission mode is set as the second transmission mode. And when the second communication nodes and the third communication nodes coexist in the communication network, the transmission mode is determined as a third transmission mode.

Here, when the transmission mode is the first transmission mode, WSA messages are transmitted only for the second communication nodes during the transmission period.

Here, when the transmission mode is the second transmission mode, WSA messages are transmitted only for the third communication nodes during the transmission period.

Here, when the transmission mode is the third transmission mode, a WSA message for only the second communication nodes, a WSA message for only the third communication nodes, and the second communication nodes and the third during the transmission period It is characterized by transmitting WSA messages for all communication nodes.

Here, the transmission period is a first transmission period in which WSA messages only for the second communication nodes are transmitted, a second transmission period in which WSA messages only for the third communication nodes are transmitted, and the second communication nodes and the It consists of a third transmission period in which WSA messages for all of the third communication nodes are transmitted, and the first transmission period, the second transmission period, and the third transmission period are the number of the second communication nodes and the third communication It is characterized in that it is determined based on the number of nodes.

이고, 상기 제3 통신 노드들의 개수가

인 경우, 상기 제1 전송 주기, 상기 제2 전송 주기 및 상기 제3 전송 주기의 비는

인 것을 특징으로 한다.Here, the number of the second communication nodes is

And the number of the third communication nodes is

In the case of, the ratio of the first transmission period, the second transmission period, and the third transmission period is

It is characterized by being.

Here, the WSA message is characterized in that it is transmitted through a control channel (CCH) channel.

The method of operating a first communication node in a communication network according to the present invention includes a first indicator indicating a transmission mode of a wireless access in vehicular environments service advertisement (WSA) message from a second communication node, and the Receiving the WSA message including a second indicator indicating a transmission period of the WSA message, checking the transmission mode of the WSA message indicated by the first indicator, and determining whether the WSA message is available Step of, if it is determined that the WSA message is available, confirming a transmission period of the WSA message indicated by the second indicator, and receiving service information included in the WSA message according to the transmission period, and the And activating the service included in the service information.

Here, the first indicator is characterized in that it includes protocol information used for a reception operation of the first communication node.

Here, the second indicator is characterized in that it includes information on the number of communication nodes that perform a reception operation using the same protocol as the first communication node.

According to the present invention, a first communication node constituting a communication network includes a processor and a memory in which at least one instruction executed by the processor is stored, and the at least one instruction is a first Check the number of second communication nodes that receive messages in the reception mode and the number of third communication nodes that receive messages in the second reception mode, and WSA (Wireless access in vehicular environments Service Advertisement) based on the identified number. Determining a transmission mode for transmitting a message, determining a transmission period for transmitting the WSA message based on the transmission mode, and transmitting the WSA message based on the transmission mode and the transmission period, A protocol used in the first reception mode and a protocol used in the second reception mode are different from each other.

Here, the WSA message may further include service information for the second communication nodes or service information for the third communication nodes.

Here, when only the second communication nodes exist in the communication network, the transmission mode is determined as a first transmission mode, and when only the third communication nodes exist in the communication network, the transmission mode is set as the second transmission mode. And, when the second communication nodes and the third communication nodes coexist in the communication network, the transmission mode is further executed to determine the third transmission mode.

Here, when the transmission mode is the first transmission mode, WSA messages are transmitted only for the second communication nodes during the transmission period.

Here, when the transmission mode is the second transmission mode, WSA messages are transmitted only for the third communication nodes during the transmission period.

Here, when the transmission mode is the third transmission mode, a WSA message for only the second communication nodes, a WSA message for only the third communication nodes, and the second communication nodes and the third during the transmission period It is characterized by transmitting WSA messages for all communication nodes.

Here, the transmission period is a first transmission period in which WSA messages only for the second communication nodes are transmitted, a second transmission period in which WSA messages only for the third communication nodes are transmitted, and the second communication nodes and the It consists of a third transmission period in which WSA messages for all of the third communication nodes are transmitted, and the first transmission period, the second transmission period, and the third transmission period are the number of the second communication nodes and the third communication It is characterized in that it is determined based on the number of nodes.

이고, 상기 제3 통신 노드들의 개수가

인 경우, 상기 제1 전송 주기, 상기 제2 전송 주기 및 상기 제3 전송 주기의 비는

인 것을 특징으로 한다.Here, the number of the second communication nodes is

And the number of the third communication nodes is

In the case of, the ratio of the first transmission period, the second transmission period, and the third transmission period is

It is characterized by being.

According to the present invention, a communication node can adjust the transmission periods of WSA messages based on the ratio of reception modes of communication nodes existing in the communication network. Therefore, the communication node can efficiently transmit the WSA message. In addition, the communication node can efficiently manage and use CCH (Control Channel) resources through which WSA messages are transmitted and received. In addition, by efficiently transmitting WSA messages, the communication node can provide a seamless C-ITS (Cooperative-Intelligent Transport Systems) service.

1 is a conceptual diagram illustrating an embodiment of a wireless LAN system.
2 is a block diagram showing an embodiment of a communication node constituting a wireless LAN system.
3 is a flowchart illustrating a station connection procedure in a wireless LAN system.
4 is a timing diagram illustrating a method of operating a communication node based on EDCA.
5 is a conceptual diagram illustrating a communication network including communication nodes.
6 is a flow chart illustrating a method of operating communication nodes in a communication network.
7 is a conceptual diagram illustrating a layer structure of a communication node in a communication network.
8 and 9 are flow charts illustrating an operation performed by a communication node to transmit a WSA message in a communication network.
10 is a conceptual diagram showing the structure of a WSA message.

In the present invention, various modifications may be made and various embodiments may be provided, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

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

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Unless otherwise defined, 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 the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate an overall understanding, the same reference numerals are used for the same elements in the drawings, and duplicate descriptions for the same elements are omitted.

A communication system (eg, a wireless local area network (LAN) system) to which embodiments according to the present invention are applied will be described. The communication system to which the embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention can be applied to various communication systems. Here, the communication system may be used with the same meaning as a communication network.

1 is a conceptual diagram illustrating an embodiment of a wireless LAN system.

Referring to FIG. 1, a wireless LAN system may include at least one basic service set (BSS). BSS refers to a set of stations (STA1, STA2 (AP1), STA3, STA4, STA5 (AP2), STA6, STA7, STA8) that can communicate with each other through successful synchronization, and does not mean a specific area. . In the following embodiments, a station performing the function of an access point may be referred to as an "access point (AP)," and a station not performing the function of an access point may be referred to as a "non-AP station" or a "station. May be referred to as ".

BSS can be classified into an infrastructure BSS (infrastructure BSS) and an independent BSS (IBSS). Here, BSS1 and BSS2 may refer to an infrastructure BSS, and BSS3 may refer to an IBSS. BSS1 is a distribution that connects a first station (STA1), a first access point (STA2 (AP1)) providing a distribution service, and a plurality of access points (STA2 (AP1), STA5 (AP2)) System (distribution system, DS) may be included. In BSS1, the first access point STA2 (AP1) may manage the first station STA1.

BSS2 includes a third station (STA3), a fourth station (STA4), a second access point (STA5 (AP2)) providing a distribution service, and a plurality of access points (STA2 (AP1), STA5 (AP2)). It may include a connecting distribution system (DS). In BSS2, the second access point STA5 (AP2) may manage the third station STA3 and the fourth station STA4.

BSS3 may mean IBSS operating in an ad-hoc mode. In BSS3, an access point, which is a centralized management entity, may not exist. That is, in BSS3, the stations STA6, STA7, and STA8 may be managed in a distributed manner. In BSS3, all the stations STA6, STA7, and STA8 may refer to mobile stations, and because access to the distribution system DS is not allowed, a self-contained network is formed.

The access points STA2 (AP1) and STA5 (AP2) may provide access to the distributed system DS through a wireless medium for the stations STA1, STA3, and STA4 coupled to them. Communication between stations STA1, STA3, and STA4 in BSS1 or BSS2 is generally performed through an access point (STA2 (AP1), STA5 (AP2)), but when a direct link is established, the stations ( Direct communication between STA1, STA3, and STA4 is possible.

A plurality of infrastructure BSSs may be interconnected through a distribution system (DS). A plurality of BSSs connected through the distribution system (DS) is referred to as an extended service set (ESS). Communication nodes (STA1, STA2 (AP1), STA3, STA4, STA5 (AP2)) included in the ESS can communicate with each other, and any station (STA1, STA3, STA4) within the same ESS communicates without interruption. You can move from one BSS to another BSS.

Distribution system (DS) is a mechanism for one access point to communicate with another access point.Accordingly, the access point transmits frames for stations coupled to the BSS managed by itself or moves to another BSS. Frames can be transmitted for any station. In addition, the access point can transmit and receive frames with an external network such as a wired network. Such a distribution system (DS) does not necessarily have to be a network, and there is no limitation on its form as long as it can provide a predetermined distribution service specified in the IEEE 802.11 standard. For example, the distribution system may be a wireless network such as a mesh network, or a physical structure that connects access points to each other. Communication nodes STA1, STA2 (AP1), STA3, STA4, STA5 (AP2), STA6, STA7, and STA8 included in the WLAN system may be configured as follows.

2 is a block diagram showing an embodiment of a communication node constituting a wireless LAN system.

Referring to FIG. 2, the communication node 200 may include at least one processor 210, a memory 220, and a transmission/reception device 230 connected to a network to perform communication. The transceiver 230 may be referred to as a transceiver, a radio frequency (RF) unit, an RF module, or the like. In addition, the communication node 200 may further include an input interface device 240, an output interface device 250, and a storage device 260. Each of the components included in the communication node 200 may be connected by a bus 270 to perform communication with each other.

However, each of the components included in the communication node 200 may be connected through an individual interface or an individual bus centering on the processor 210 instead of the common bus 270. For example, the processor 210 may be connected to at least one of the memory 220, the transmission/reception device 230, the input interface device 240, the output interface device 250, and the storage device 260 through a dedicated interface. .

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 mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured with at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 220 may be formed of at least one of a read only memory (ROM) and a random access memory (RAM). Meanwhile, in the wireless LAN system, the connection procedure may be performed as follows.

3 is a flowchart illustrating a station connection procedure in a wireless LAN system.

3, in the infrastructure BSS, the connection procedure of a station (STA) is largely a probe step, an authentication step with the detected access point (AP), and authentication. It can be divided into an association step with an access point (AP) that has performed the procedure.

The station STA may first detect neighboring access points APs using a passive scanning method or an active scanning method. When using the passive scanning method, the station STA may detect neighboring access points APs by overhearing beacons transmitted by the access points APs. When using the active scanning method, the station (STA) can transmit a probe request frame, and receives a probe response frame, which is a response to the probe request frame, from APs. By doing so, neighboring access points (APs) can be detected.

When neighboring access points (APs) are detected, the station (STA) may perform an authentication step with the detected access points (AP). In this case, the station STA may perform an authentication step with a plurality of access points APs. The authentication algorithm according to the IEEE 802.11 standard can be classified into an open system algorithm exchanging two authentication frames, a shared key algorithm exchanging four authentication frames, and the like.

The station (STA) may transmit an authentication request frame based on an authentication algorithm according to the IEEE 802.11 standard, and an authentication response frame that is a response to the authentication request frame from the access point (AP). By receiving, authentication with the access point (AP) can be completed.

When authentication with the access point (AP) is completed, the station (STA) may perform a connection step with the access point (AP). In this case, the station STA may select one of the access points APs that have performed the authentication step with itself and may perform a connection step with the selected access point AP. That is, the station (STA) may transmit an association request frame (association request frame) to the selected access point (AP), and the association response frame (association response frame) that is a response to the connection request frame from the selected access point (AP) By receiving, it is possible to complete the connection with the selected access point (AP).

On the other hand, communication nodes (eg, access points, stations, etc.) belonging to the WLAN system are PCF (point coordination function), HCF (hybrid coordination function), HCCA (HCF controlled channel access), DCF (distributed coordination function), A frame transmission/reception operation may be performed based on an enhanced distributed channel access (EDCA) or the like.

In a wireless LAN system, frames may be classified into a management frame, a control frame, and a data frame. The management frame is an association request frame, a response frame, a reassociation request frame, a reconnection response frame, a probe request frame, a probe response frame, a beacon frame, and a connection. It may include a disassociation frame, an authentication frame, a deauthentication frame, an action frame, and the like.

The control frame includes an acknowledgment (ACK) frame, a block ACK request (BAR) frame, a block ACK (BA) frame, a power saving (PS)-Poll frame, a request to send (RTS) frame, a clear to send (CTS) frame, and the like. Can include. Data frames may be classified into quality of service (QoS) data frames and non-QoS (non-QoS) data frames. The QoS data frame may indicate a data frame requiring transmission according to QoS, and the non-QoS data frame may indicate a data frame not requiring transmission according to QoS. Meanwhile, in a wireless LAN system, a communication node (eg, an access point, a station) may operate based on the EDCA.

4 is a timing diagram illustrating a first embodiment of a method of operating a communication node based on EDCA.

Referring to FIG. 4, a communication node that wants to transmit a control frame (or a management frame) monitors the channel state during a preset period (eg, short interframe space (SIFS), PIFS (PCF IFS)). When an operation (for example, a carrier sensing operation) can be performed and the channel state is determined to be an idle state during a preset period (for example, SIFS, PIFS), the control frame ( Alternatively, a management frame) may be transmitted. For example, the communication node may transmit an ACK frame, a BA frame, a CTS frame, and the like when the channel state is determined to be an idle state during SIFS. Also, the communication node may transmit a beacon frame or the like when it is determined that the channel state is an idle state during PIFS. On the other hand, when the channel state is determined to be busy during a preset period (eg, SIFS, PIFS), the communication node may not transmit a control frame (or a management frame). Here, the carrier sensing operation may indicate a clear channel assessment (CCA) operation.

A communication node that wants to transmit a non-QoS data frame can perform a channel state monitoring operation (eg, a carrier sensing operation) during DIFS (DCF IFS), and when the channel state is determined to be an idle state during DIFS A random backoff procedure can be performed. For example, the communication node may select a backoff value (eg, a backoff counter) within a contention window according to a random backoff procedure, and a section corresponding to the selected backoff value (hereinafter, "backoff counter") During the "off period"), a channel state monitoring operation (eg, a carrier sensing operation) may be performed. The communication node may transmit a non-QoS data frame when it is determined that the channel state is an idle state during the backoff period.

A communication node that wants to transmit a QoS data frame can perform a channel state monitoring operation (e.g., a carrier sensing operation) during AIFS (arbitration IFS), and if the channel state is determined to be idle during AIFS, random back The off procedure can be performed. AIFS may be set according to an access category (AC) of a data unit (eg, a protocol data unit (PDU)) included in a QoS data frame. The AC of the data unit may be as shown in Table 1 below.

AC_BK may indicate background data, AC_BE may indicate data transmitted in a best effort method, AC_VI may indicate video data, and AC_VO may indicate voice ( voice) data can be indicated. For example, the length of AIFS for QoS data frames corresponding to AC_VO and AC_VI may be set equal to the length of DIFS. The AIFS length for the QoS data frame corresponding to each of AC_BE and AC_BK may be set longer than the length of DIFS. Here, the length of the AIFS for the QoS data frame corresponding to AC_BK may be set to be longer than the length of the AIFS for the QoS data frame corresponding to AC_BE.

In the random backoff procedure, the communication node may select a backoff value (eg, a backoff counter) within a contention window according to AC of a QoS data frame. The competition window according to AC may be shown in Table 2 below. CW _min may indicate the minimum value of the contention window, CW _max may indicate the maximum value of the contention window, and each of the minimum and maximum values of the contention window may be expressed as the number of slots.

The communication node may perform a channel state monitoring operation (eg, a carrier sensing operation) during the backoff period, and may transmit a QoS data frame when the channel state is determined to be an idle state during the backoff period.

Next, methods of operating a wireless LAN multi-channel in a communication system will be described. Even when a method performed in the first communication node (for example, transmission or reception of a signal) among communication nodes is described, the second communication node corresponding thereto is a method corresponding to the method performed in the first communication node (e.g. For example, signal reception or transmission) may be performed. That is, when the operation of the terminal is described, the corresponding base station may perform an operation corresponding to the operation of the terminal. Conversely, when the operation of the base station is described, the terminal corresponding thereto may perform an operation corresponding to the operation of the base station.

In the following, a wireless communication network including communication nodes performing inter-vehicle communication will be described. Meanwhile, the wireless communication network to which the embodiments according to the present invention are applied is not limited to the contents described below, and may be applied to various wireless communication networks.

5 is a conceptual diagram illustrating a communication network including communication nodes.

Referring to FIG. 5, vehicles 510 and 520 may be driving on a road, and a roadside base station 530 may be located on the side of the road. Vehicles 510 and 520 may include vehicle terminals 512 and 522 and external devices 514 and 524. The communication network may include vehicle terminals 512 and 522, external devices 514 and 524, and roadside base stations 530.

The vehicle terminals 512 and 522 may be On Board Equipment (OBE) mounted on each vehicle 510 and 520. The vehicle terminals 512 and 522 may be devices that receive related data according to the information service provided by the roadside base station 530, activate the corresponding service, and output various information.

The information output by activating the service by the vehicle terminals 512 and 522 may include not only traffic-related information, but also information related to gas stations, rest areas, vehicle repair stations, weather, and the like. The vehicle terminals 512 and 522 may perform wireless communication with the roadside base station 530. In addition, wireless communication between the vehicle terminals 512 and 522 may be performed. Vehicle terminals 512 and 522 may have a communication interface for this.

The vehicle terminal 512 may perform wireless communication with another vehicle terminal 522 or roadside base station 530 using WAVE (Wireless Access in Vehicular Environments). WAVE can facilitate wireless communication between the vehicle terminals 512 and 522 and the roadside base station 530 in an environment in which the location of the communication terminal is severely changed and information must be exchanged in a short period of time.

The external devices 514 and 524 may be located in vehicles 510 and 520 on which the vehicle terminal 512 is mounted in order to perform wired or wireless communication. The external devices 514 and 524 may not be equipped with a WAVE communication function. The external devices 514 and 524 may be devices that can be located in vehicles 510 and 520 such as a smart phone, a mobile phone, a navigation system, a black box, a tablet, and a laptop.

The external devices 514 and 524 may communicate with the vehicle terminals 512 and 522 using Ethernet/Wireless Fidelity (Wi-Fi) or User Datagram Protocol (UDP). Vehicle terminals 512 and 522 may communicate with external devices 514 and 524 mounted on vehicles 510 and 520. The vehicle terminals 512 and 522 may transmit and receive data using Ethernet/Wi-Fi or UDP. In this case, the external devices 514 and 524 may receive the WAVE communication service through the vehicle terminals 512 and 522 equipped with the WAVE communication function.

The roadside base station 530 may perform wireless communication with vehicle terminals 512 and 522 mounted on vehicles 510 and 520 traveling on a road. The roadside base station 530 may be an Intelligent Transport System (ITS) base station located within a certain distance along the road. ITS can mean an intelligent transportation system that can comprehensively collect and provide traffic information by applying information and communication technology. Therefore, ITS can provide a system that can effectively solve problems such as traffic jams. The roadside base station 530 may be a type of Road Side Unit (RSU). The roadside base station 530 provides a service to the vehicle terminals 512 and 522 mounted on the vehicles 510 and 520 based on the service information stored inside or the service information provided by an external server (e.g., traffic information service Etc.) can be provided. The roadside base station 530 may include a communication interface for wireless communication with the vehicle terminals 510 and 520.

6 is a flow chart illustrating a method of operating communication nodes in a communication network.

Referring to FIG. 6, the roadside base station 530 may periodically transmit a WSA message including information on services that it can provide through a control channel (CCH) (S601 and S602). More specifically, the roadside base station 530 may periodically broadcast a WSA message to vehicles entering within its communication radius through a control channel.

Vehicle terminals 512 and 522 mounted on vehicles 510 and 520 may continuously monitor the control channel until access to the roadside base station 530. Vehicles 510 and 520 may monitor the control channel, and when entering the radio wave arrival section of the roadside base station 530, may receive a WSA message through the monitored control channel (S603, S604).

Meanwhile, the vehicle terminal 512 included in the vehicle 510 and the vehicle terminal 522 included in the vehicle 520 may have different modes for receiving the WSA message. That is, a protocol for receiving a WSA message may be different. For example, the vehicle terminal 512 included in the vehicle 510 may be a terminal receiving a WSA message based on IEEE (Institute of Electrical and Electronics Engineers) 802.11p, and a vehicle terminal included in the vehicle 520 Reference numeral 522 may be a terminal receiving a WSA message based on IEEE 802.11bd, which is an improved version of IEEE 802.11p. Accordingly, vehicle terminals 512 and 522 having different data reception modes may coexist on the communication network. When the modes in which the vehicle terminals 512 and 522 receive the WSA message are different, services for each vehicle terminal may be different. In this case, information included in the WSA message transmitted for service advertisement may also be different.

In an environment in which vehicle terminals 512 and 522 having different reception modes coexist, the roadside base station 530 needs to transmit a WSA message to all of the vehicle terminals 512 and 522. That is, the roadside base station 530 needs to transmit a suitable WSA message to each vehicle terminal in steps S601 and S602.

If the roadside base station 530 transmits only WSA messages for vehicle terminals having a specific reception mode, there may be a problem of transmitting only specific PHY Protocol Data Units (PPDUs). In addition, service advertisement opportunities in the control channel (CCH) are provided unevenly, which may lead to channel inefficiency. For example, there is one vehicle in the vicinity of the roadside base station 530 that receives a WSA message in a first reception mode, and ten vehicles receive a WSA message in a second reception mode that is different from the first reception mode. If present, it may be desirable for the roadside base station 530 to allow 10 vehicles to smoothly receive the service. That is, the roadside base station 530 may transmit the WSA message in consideration of the ratio of vehicles having different WSA message reception modes existing in the vicinity. Hereinafter, a process of generating and transmitting a WSA message by the roadside base station 530 will be described in detail with reference to FIGS. 7 to 10.

7 is a conceptual diagram illustrating a layer structure of a communication node in a communication network.

Referring to FIG. 7, a communication node performing vehicle-to-everything (V2X) communication is an application layer, which is the highest layer, and an operation of a transport layer to ensure reliability of frame transmission between communication nodes. UDP/TCP to perform the operation, IPv6 to perform a network layer operation to search for transmission paths between multiple nodes, and a logical link control (LLC) sublayer of the data link layer for transmission between points ( sublayer), a medium access control (MAC) layer, and a physical layer (PHY) for transmitting and receiving an actual signal.

The application layer can implement and support various use cases or applications. For example, the application layer may provide various applications in a communication system including a vehicle to vehicle (V2V) application, a vehicle to infrastructure (V2I) application, and a vehicle to others (V2O) application.

The facility layer may be a layer for effectively implementing various usage examples defined by an application layer. For example, the facility layer may be a layer that generates a message (or message set) based on information to be transmitted from an application layer that is an upper layer.

The network/transport layer may be a layer constituting a network for V2X communication by supporting various network protocols and transport protocols. A network for V2X communication may include a homogenous network and/or a heterogenous network. For example, the network and transport layer may provide Internet access and routing to a communication node through an Internet protocol such as TCP/UDP+IPv6.

Meanwhile, in the case of communication between vehicle terminals, since the transmitting terminal can directly transmit the frame through the receiving terminal, an operation of transmitting the frame to the receiving terminal through another terminal may be unnecessary. Thus, the communication node may not require the existing network/transport layer and data link layer. Accordingly, in order to simplify the function of the network/transport layer, some functions of the network/transport layer and the data link layer may be replaced with a WAVE short message protocol (WSMP).

The access layer may be a layer that transmits messages/data received from upper layers through a physical channel. For example, the access layer may support an IEEE 802.11 and/or 802.11p standard-based communication technology, and an IEEE 1609 and/or IEEE 1609.4 standard-based communication technology. In addition, the access layer may transmit messages and/or data through a physical channel. The access layer may include a media access control (MAC) layer and a PHY layer. The MAC layer of the communication node constituting the V2X communication system may be a WSMP MAC layer. Each of the layers may transfer data and/or signals to a lower layer as described below.

Each of the layers constituting the communication node may transmit corresponding data and additional information through a service access point (SAP). For example, the LLC layer may obtain data and parameters such as a source address and a destination address from WSMP or IPv6 through a link service access point (LSAP). In particular, the LLC layer may obtain channel load information measured by the communication node from the WSMP through LSAP. The LSAP used in WAVE may be the same as the SAP used in the existing WLAN except for the DL-UNITDATA.req primitives, which are parameters transmitted from the upper layer. The DL-UNITDATA.req primitive may further include a parameter for a WAVE-related operation, and may be delivered in the form of a DL-UNITDATAX.req primitive. The DL-UNITDATAX.req primitive may include the parameters of Table 3.

In Table 3, among the parameters transmitted through the LSAP, the channel load may indicate the degree of congestion of the channel. The channel load may be included in the WSMP message and transmitted to another terminal, or may be transmitted to the MAC layer through MAC SAP and used to perform an operation according to the channel state. The channel load may be information obtained as a channel load parameter of the DL-UNITDATAX.req primitive in LSAP. The channel load can be transmitted to the MAC layer by adding a channel load parameter to the MA-UNITDATA.req primitive of MAC SAP of the existing WLAN.

The management layer may be a layer that manages the operation of layers included in the communication node. The management layer may provide services and information for management and operation of the facility layer through an MF (interface between management entity and facilities layer) (or MF-SAP). In addition, the management layer may provide services and information for management and operation of the network/transport layer and the access layer through an interface with the network/transport layer and the access layer. The management layer may be divided into a WME (WAVE Management Entity) layer, a WME-MIB (Management Information Base) layer, and a MLMEX (MAC Sublayer Management Entity Extension) layer according to roles.

The security layer may be a layer that manages security-related information of layers included in the communication node. The security layer may provide services and information for security of the facility layer through an interface between security entity and facilities layer (SF) (or MF-SAP). In addition, the security layer may provide information on security of the network/transport layer and the access layer through an interface with the network/transport layer and the access layer.

8 and 9 are flow charts illustrating an operation performed by a communication node to transmit a WSA message in a communication network. More specifically, FIG. 8 shows a process in which a communication node sets a transmission mode for transmission of a WSA message, and FIG. 9 shows a process in which a communication node sets a transmission period for transmission of a WSA message.

Referring to FIG. 8, an upper layer (eg, an application layer) of the roadside base station 530 may request a service from a WME (WAVE Management Entity) layer through the WME-ProviderService.req primitive (S801). The WME-ProviderService.req primitive may include an indicator (Tx_mode) 810 indicating a transmission mode. The indicator 810 may be an indicator for determining a transmission mode for the roadside base station 530 to transmit a WSA message.

Meanwhile, the upper layer may determine the transmission mode of the WSA message. The upper layer may set the indicator 810 indicating the transmission mode based on service information (contents) included in the WSA message. The indicator 810 for determining the transmission mode of the WSA message may be included in the ProviderService.req primitive and transmitted. Thereafter, the roadside base station 530 may determine the transmission mode of the WSA message based on the indicator 810.

For example, if the service included in the WSA message is a service only for communication nodes that support a first reception mode (eg, a terminal based on IEEE 802.11p), the roadside base station 530 may use the first transmission mode. WSA messages can be sent. The first transmission mode may be a mode set when only communication nodes supporting the first reception mode exist on the communication network.

If the service included in the WSA message is a service only for communication nodes supporting the second reception mode (eg, IEEE 802.11bd-based terminal), the roadside base station 530 transmits the WSA message in the second transmission mode. I can. The second transmission mode may be a mode configured when only communication nodes supporting the second reception mode exist on the communication network.

A service included in the WSA message supports a service for communication nodes supporting a first reception mode, a service for communication nodes supporting a second reception mode, and communication nodes supporting a first reception mode and a second reception mode In the case of including a service for communication nodes (ie, a service having similar requirements or a common service), the roadside base station 530 may transmit the WSA message in the third transmission mode. The third transmission mode may be a mode set when communication nodes supporting the first reception mode and communication nodes supporting the second reception mode coexist on the communication network. Meanwhile, the third transmission mode may be the same as or different from one of the first transmission mode and the second transmission mode.

The WME layer may deliver a service to be provided through the WME-Set.req primitive to the WME-MIB (Management Information Base) layer (S802). The WME-MIB layer can register the delivered service. The WME layer can manage management information through the WME-MIB layer. The WME layer may respond to a service request to an upper layer through the WME-ProviderService.cfm primitive (S803). The WME layer may allocate a channel for transmitting the WSA message (S804). The WME layer may transmit a service status to the WME-MIB layer through the WME-Set.req primitive (S805). The WME-MIB layer can register the status of the delivered service.

The WME layer is the MLMEX-CHSTART.req primitive with the MLMEX (MAC Sublayer Management Entity Extension) layer, the MLMEX-CHSTART.cfm primitive (S806, S807), the WSM-WaveShortMessage.req primitive with the WSMP (WAVE Short Message Protocol) layer, and WSA message scheduling can be performed through the WSM-WaveShortMessage.cfm primitive (S808, S809), the MLMEX-REGISTERTXPROFILE.req primitive with the MLMEX layer, and the MLMEX-REGISTERTXPROFILE.cfm primitive (S810, S811).

The WSM-WaveShortMessage.req primitive may include an indicator (Tx_mode) 810 indicating a transmission mode. The indicator 810 for determining the transmission mode of the WSA message may be included in the WSM-WaveShortMessage.req primitive and transmitted. The WSMP layer may deliver a data packet to the LLC (Logical Link Control) layer through the DL-UNITDATAX.req primitive (S812). The DL-UNITDATAX.req primitive may include an indicator (Tx_mode) 810 indicating a transmission mode. The indicator 810 for determining the transmission mode of the WSA message may be included in the DL-UNITDATAX.req primitive and transmitted.

The LLC layer may deliver a data packet to the MAC/PHY layer through the MA-UNITDATAX.req primitive (S813). The MAC/PHY layer may transmit a response to the MA-UNITDATAX.req primitive through the MA-UNITDATAX.req primitive (S814). The MAC/PHY layer may transmit a WSA message through a control channel (CCH) according to a set transmission period (S815). That is, the roadside base station 530 may inform the communication nodes of its service type through a WSA message.

Referring to FIG. 9, the communication node may set a transmission period for transmission of a WSA message. Steps S901 to S904 performed through the layers of the roadside base station 530 may be similar to steps S801 to S804 of FIG. 8. The roadside base station 530 may repeat steps S901 to S904 to register WSA messages received in different modes with the WME.

The WME layer may request the MLMEX layer (or MLME layer) to set the transmission period indicator 910 through the MLME-GET.req primitive (S905). The transmission period indicator 910 may be expressed as "Percentage". The MLMEX layer (or MLME layer) may transmit a response to the MLME-GET.req primitive through the MLME-GET.cfm primitive (S906).

When the transmission mode in which the roadside base station 530 transmits the WSA message is the first transmission mode, the transmission period indicator may be set to '0' (ie, "Percentage" may be set to 0). In this case, the roadside base station 530 may transmit a WSA message only for communication nodes that receive the WSA message in the first reception mode during the transmission period.

When the transmission mode in which the roadside base station 530 transmits the WSA message is the second transmission mode, the transmission period indicator may be set to '1' (ie, "Percentage" may be set to 1). In this case, the roadside base station 530 may transmit a WSA message only for communication nodes that receive the WSA message in the second reception mode during the transmission period.

When the transmission mode in which the roadside base station 530 transmits the WSA message is the third transmission mode, the transmission period indicator may be set to a value greater than 0 and less than 1 (ie, "Percentage" is between 0 and 1). Can be set to a value). At this time, the roadside base station 530 includes a WSA message only for communication nodes receiving a WSA message in a first reception mode during a transmission period, a WSA message only for communication nodes receiving a WSA message in a second reception mode, and A WSA message may be transmitted for both communication nodes receiving the WSA message in the first receiving mode and the communication nodes receiving the WSA message in the second receiving mode.

In this way, when the roadside base station 530 transmits the WSA message in the third transmission mode, different from the first transmission mode and the second transmission mode, it may transmit three types of WSA messages. The roadside base station 530 may adjust the period in which three types of WSA messages are transmitted. The roadside base station 530 is based on the number of second communication nodes that receive messages in the first reception mode existing in the communication network and the number of third communication nodes that receive messages in the second reception mode. It is possible to determine the period in which WSA messages are transmitted.

이고, 제3 통신 노드들의 개수가

인 경우, 제2 통신 노드들만을 위한 WSA 메시지, 제3 통신 노드들만을 위한 WSA 메시지, 제2 통신 노드들 및 제3 통신 노드들 모두를 위한 WSA 메시지가 전송되는 주기의 비(ratio)는

일 수 있다. 즉, 각 WSA 메시지의 전송 주기는 통신 네트워크에 존재하는 동일한 수신 모드를 가지는 통신 노드들의 개수에 비례하여 결정될 수 있다. WME 레이어는 설정된 전송 주기 지시자(910)에 기초하여 각 WSA 메시지가 전송되는 주기를 설정할 수 있다(S907).For example, the number of second communication nodes is

And the number of third communication nodes is

In the case of, the ratio of the period in which the WSA message only for the second communication nodes, the WSA message only for the third communication nodes, and the WSA message for both the second communication nodes and the third communication nodes is transmitted is

Can be That is, the transmission period of each WSA message may be determined in proportion to the number of communication nodes having the same reception mode in the communication network. The WME layer may set a period in which each WSA message is transmitted based on the set transmission period indicator 910 (S907).

Meanwhile, the ratio of transmission periods of the WSA messages may be determined in consideration of the repeat rate of the WSA message. The WME layer may transmit a repeat rate to the WME-MIB layer through the WME-SET.req primitive (S908). The WME-MIB layer may register the transmitted repeat rate. The WME-MIB layer may deliver a response to S908 to the WME layer through the WME-SET.cfm primitive (S909). Here, the repeat rate may mean the number of times an advertisement message is transmitted every 5 seconds, and the repeat rate may be information included in the WME-providerService.req primitive of FIG. 8.

For example, the repeat rates of WSA messages only for m second communication nodes receiving the WSA message in the first reception mode are a ₁ , a ₂ , a ₃ ,… , a _m , and the repeat rates of WSA messages only for n third communication nodes receiving WSA messages in the second reception mode are b ₁ , b ₂ , b ₃ ,… , b _n , and the repeat rates of WSA messages for both the second communication nodes receiving the WSA message in the first receiving mode and the third communication node receiving the WSA message in the second receiving mode are c ₁ , c ₂ , respectively. , c ₃ ,… , c may be _m+n . In this case, the ratio of transmission periods of the WSA messages is (a ₁₊ a ₂₊ a _3, …+a _m ):(b ₁₊ b ₂₊ b _3, …+b _n ): (c ₁₊ c _{2 +} c _3, …+c _m+n ). Accordingly, the transmission periods for WSA messages only for the second communication nodes, WSA messages only for the third communication nodes, and the WSA messages for the second communication nodes and the third communication nodes may be set according to the ratio. I can.

The WME layer may deliver the data packet to the WSMP layer through the WME-WaveShorMessage.req primitive (S910). The WSMP layer may deliver a response to S910 to the WME layer through the WME-WaveShorMessage.cfm primitive (S911). Steps S910 and S911 may be repeated whenever a repeat rate value for transmission of a WSA message is changed. Meanwhile, steps S905 to S911 may be repeatedly performed every update period of the transmission period indicator 910.

Referring back to FIG. 6, vehicles 510 and 520 may receive a WSA message from the roadside base station 530 (S603 and S604). 10 is a conceptual diagram showing the structure of a WSA message. Referring to FIG. 10, the WSA message transmitted by the roadside base station 530 may be composed of a WSA header and a payload. Here, the WSA header is a WSA version field, a WSA header option indicator field, a WSA identifier field, a content count field, and a WAVE Information Element Extension. ) Field. The repeat rate parameter may be included in the WAVE information element extension field, and the roadside base station 530 may determine a transmission period indicator based on the repeat rate parameter. The indicator indicating the transmission mode and the indicator indicating the transmission period may be included in the WSA message field.

Referring back to FIG. 6, vehicles 510 and 520 may receive a WSA message from the roadside base station 530, and a first indicator indicating a transmission mode included in the WSA message and a second indicating a transmission period. You can check the indicator. Vehicle terminals 512 and 522 included in the vehicles 510 and 520 may check the transmission mode of the WSA message indicated by the first indicator and determine whether or not the WSA message is available. Here, the process of determining whether the WSA message is available is a process of determining whether the transmission mode in which the roadside base station 530 transmits the WSA message and the mode in which the vehicle terminals 512 and 522 receive the WSA message are compatible. Can be The first indicator may include protocol information used for a reception operation of a communication node. When it is determined that the vehicle terminals 512 and 522 can use the WSA message, the vehicle terminals 512 and 522 may check the transmission period of the WSA message indicated by the second indicator and receive the WSA message. . Here, the second indicator may include information on the number of communication nodes performing a reception operation using the same protocol.

Vehicle terminals 512 and 522 included in the vehicles 510 and 520 may activate a service channel for exchanging service information with the roadside base station 530 (S605 and S606). In addition, the roadside base station 530 and the vehicle terminals 512 and 522 may exchange information through an activated service channel (S607 and S608). Thereafter, the vehicle terminals 512 and 522 may activate a service provided by the roadside base station 530 (S609 and S610).

The methods according to the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in 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 specially designed and configured for the present invention, or may be known and usable to those skilled in computer software.

Examples of computer-readable media include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The above-described hardware device may be configured to operate as at least one software module to perform the operation of the present invention, and vice versa.

Although described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention described in the following claims. I will be able to.

Claims (20)

As a method of operating a first communication node in a communication network,
Confirming the number of second communication nodes receiving the message in the first receiving mode and the number of third communication nodes receiving the message in the second receiving mode;
Determining a transmission mode for transmitting a Wireless access in vehicular environments Service Advertisement (WSA) message based on the identified number;
Determining a transmission period for transmitting the WSA message based on the transmission mode; And
And transmitting the WSA message based on the transmission mode and the transmission period, wherein a protocol used in the first reception mode and a protocol used in the second reception mode are different from each other. A method of operating the first communication node. The method according to claim 1,
The WSA message further includes service information for the second communication nodes or service information for the third communication nodes. The method according to claim 1,
When only the second communication nodes exist in the communication network, the transmission mode is determined as a first transmission mode, and when only the third communication nodes exist in the communication network, the transmission mode is determined as a second transmission mode And when the second communication nodes and the third communication nodes coexist in the communication network, the transmission mode is determined as a third transmission mode. The method of claim 3,
When the transmission mode is the first transmission mode, WSA messages are transmitted only for the second communication nodes during the transmission period. The method of claim 3,
When the transmission mode is the second transmission mode, WSA messages are transmitted only for the third communication nodes during the transmission period. The method of claim 3,
When the transmission mode is the third transmission mode, during the transmission period, a WSA message for only the second communication nodes, a WSA message for only the third communication nodes, and the second communication nodes and the third communication node A method of operating a first communication node, characterized in that transmitting a WSA message for all of them. The method of claim 6,
The transmission period is a first transmission period in which a WSA message only for the second communication nodes is transmitted, a second transmission period in which a WSA message only for the third communication nodes is transmitted, and the second communication nodes and the third It consists of a third transmission period in which WSA messages for all communication nodes are transmitted, and the first transmission period, the second transmission period, and the third transmission period are the number of the second communication nodes and the number of the third communication nodes. It characterized in that it is determined based on the number, the operation method of the first communication node. The method of claim 7,
The number of the second communication nodes is

And the number of the third communication nodes is

In the case of, the ratio of the first transmission period, the second transmission period, and the third transmission period is

Characterized in that, the operation method of the first communication node. The method according to claim 1,
The WSA message is transmitted through a control channel (CCH) channel. As a method of operating a first communication node in a communication network,
Receiving the WSA message including a first indicator indicating a transmission mode of a wireless access in vehicular environments service advertisement (WSA) message from a second communication node and a second indicator indicating a transmission period of the WSA message;
Checking a transmission mode of the WSA message indicated by the first indicator, and determining whether the WSA message is available;
If it is determined that the WSA message is available, checking a transmission period of the WSA message indicated by the second indicator, and receiving service information included in the WSA message according to the transmission period; And
A method of operating a first communication node, comprising activating a service included in the service information. The method of claim 10,
The first indicator comprises protocol information used for a reception operation of the first communication node. The method of claim 10,
The second indicator includes information on the number of communication nodes that perform a reception operation using the same protocol as the first communication node. As a first communication node constituting a communication network,
Processor; And
And a memory in which at least one instruction executed by the processor is stored,
The at least one command,
Ascertaining the number of second communication nodes receiving the message in the first receiving mode and the number of third communication nodes receiving the message in the second receiving mode;
Determining a transmission mode for transmitting a Wireless access in vehicular environments Service Advertisement (WSA) message based on the identified number;
Determining a transmission period for transmitting the WSA message based on the transmission mode; And
The second reception mode is executed to transmit the WSA message based on the transmission mode and the transmission period, and a protocol used in the first reception mode and a protocol used in the second reception mode are different from each other. 1 communication node. The method of claim 13,
The WSA message further comprises service information for the second communication nodes or service information for the third communication nodes. The method of claim 13,
When only the second communication nodes exist in the communication network, the transmission mode is determined as a first transmission mode, and when only the third communication nodes exist in the communication network, the transmission mode is determined as a second transmission mode And when the second communication nodes and the third communication nodes coexist in the communication network, the first communication node is further executed to determine the transmission mode as a third transmission mode. The method of claim 15,
If the transmission mode is the first transmission mode, characterized in that the transmission of the WSA message only for the second communication nodes during the transmission period, the first communication node. The method of claim 15,
If the transmission mode is the second transmission mode, characterized in that for transmitting only the WSA message for the third communication nodes during the transmission period, the first communication node. The method of claim 15,
When the transmission mode is the third transmission mode, during the transmission period, a WSA message for only the second communication nodes, a WSA message for only the third communication nodes, and the second communication nodes and the third communication node A first communication node, characterized in that transmitting a WSA message for all of them. The method of claim 18,
The transmission period is a first transmission period in which a WSA message only for the second communication nodes is transmitted, a second transmission period in which a WSA message only for the third communication nodes is transmitted, and the second communication nodes and the third It consists of a third transmission period in which WSA messages for all communication nodes are transmitted, and the first transmission period, the second transmission period, and the third transmission period are the number of the second communication nodes and the number of the third communication nodes. The first communication node, characterized in that it is determined based on the number. The method of claim 19,
The number of the second communication nodes is

And the number of the third communication nodes is

In the case of, the ratio of the first transmission period, the second transmission period, and the third transmission period is

Characterized in that, the first communication node.

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