WO2019139194A1

WO2019139194A1 - V2x communication device and geo-networking transmission method

Info

Publication number: WO2019139194A1
Application number: PCT/KR2018/000656
Authority: WO
Inventors: 백서영; 고우석
Original assignee: 엘지전자(주)
Priority date: 2018-01-15
Filing date: 2018-01-15
Publication date: 2019-07-18

Abstract

Disclosed is a geo-networking transmission method of a V2X communication device. A geo-networking transmission method according to an embodiment of the present invention comprises the steps of: determining a forwarder from neighboring V2X communication devices included in location information, and setting an address of the determined forwarder as a link layer address; transmitting a geo-networking packet on the basis of the link layer address; and retransmitting the geo-networking packet at specific time intervals until a maximum repetition time expires.

Description

V2X communication device and geo-networking transfer method

The present invention relates to a device for V2X communication and a geo-networking transmission method thereof, and more particularly, to a forwarding algorithm capable of reliably transmitting data outside a transmission range.

In recent years, vehicles have become a result of complex industrial technology that is a fusion of electric, electronic, and communication technologies centering on mechanical engineering. In this respect, vehicles are also called smart cars. Smart cars have been providing various customized mobile services as well as traditional vehicle technologies such as traffic safety / complicatedness by connecting drivers, vehicles, and transportation infrastructures. This connectivity can be implemented using V2X (Vehicle to Everything) communication technology.

Various services can be provided through V2X communication. In addition, a plurality of frequency bands have been used to provide various services. In this environment, reliable communication and delivery of safety service is very important because of the nature of vehicle communication.

In V2X communication, a geo-networking transmission method using hopping can be used to transmit data outside the transmission range. In geo-networking transmissions, packet forwarding algorithms can be used for data hopping and destination delivery. Especially, in the V2X communication environment where the communication environment changes dynamically, the efficiency and reliability of the packet forwarding algorithm must be considered.

According to an aspect of the present invention, there is provided a geo-networking method for a V2X communication apparatus, the method comprising: determining a forwarder from neighbor V2X communication devices included in location information; To a link layer address; Transmitting a geo-networking packet based on the link layer address; And retransmitting the geo-networking packet at specific time intervals until a maximum repetition time expires, wherein the location information includes information about at least one neighbor V2X communication device executing a geo-networking protocol, The forwarder is determined based on the distance between the neighboring V2X communication devices included in the localization information and the destination.

In the geo-networking transmission method according to the embodiment of the present invention, when a conform packet is received from the forwarder, retransmission of the geo-networking packet may be terminated.

In the geo-networking transmission method according to an embodiment of the present invention, the conform packet may correspond to a sender conform packet in which the forwarder confirms receipt of the geo-networking packet, or the destination V2X communication device transmits the geo- It may correspond to a destination-conform packet that agrees to reach the destination region of the packet.

In the geo-networking transmission method according to an embodiment of the present invention, the sender confirm packet includes at least one of a received sequence number information and a conform status information, and the received sequence number information includes sequence number information of the transmitted geo-networking packet , And the conform status information may indicate whether the forwarder is capable of forwarding the geo-networking packet and an impossible state if forwarding is not possible.

In the geo-networking transmission method according to an exemplary embodiment of the present invention, the destination confirm packet includes at least one of sequence number information, received sequence number information, and redundancy number information, The received sequence number information has the same value as the sequence number information of the transmitted geo-networking packet, and the duplicate number information may indicate the number of arrivals of the same packet.

In the geo-networking transmission method according to an exemplary embodiment of the present invention, the destination confirm packet further includes source position vector information and destination position vector information, and the source position vector information includes information on a destination of the destination V2X communication apparatus, and the destination position vector information may indicate a position vector of the source V2X communication apparatus that multi-hop transmits the geo-networking packet.

In the geo-networking transmission method according to an embodiment of the present invention, the sender confirm packet corresponds to a single hop packet, and the destination confirm packet corresponds to a multi-hop packet.

According to another aspect of the present invention, there is provided a V2X communication apparatus including: a memory for storing data; A communication unit for transmitting and receiving a radio signal including geo-networking packets; And a processor for controlling the memory and the communication unit, the processor determining a forwarder from the neighboring V2X communication devices included in the location information, setting the address of the determined forwarder as a link layer address , Transmitting a geo-networking packet based on the link-layer address, and retransmitting the geo-networking packet at specific time intervals until a maximum repetition time ends, the location information comprising at least one neighbor V2X And the forwarder is determined based on the distance between the neighboring V2X communication devices included in the localization information and the destination.

According to the present invention, it is possible to prevent unnecessary repetitive transmission of the same packet by transmitting a CONFESS packet to the sender router that the packet has been received in the forwarding router. In addition, it is possible to prevent unnecessary repetitive transmission of the same packet by transmitting a CONFESS packet to the source router that the packet has been received from the destination router. By using the conform packet, it is possible to reduce the repetitive transmission of unnecessary packets and improve the channel use efficiency. In addition, packet reception at the final destination can be confirmed, and more reliable packet transmission with guaranteed QoS can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

1 shows a protocol structure of an ITS system according to an embodiment of the present invention.

2 shows a packet structure of a network / transport layer according to an embodiment of the present invention.

3 is a header structure of a geo-networking packet according to an embodiment of the present invention, and shows a structure of a basic header and a common header.

FIG. 4 illustrates a geographically-scoped unicast (GUC) type geo-networking method according to an embodiment of the present invention and a GUC packet header structure according to the method.

5 is a topologically scoped broadcast (TSB) type geo-networking method according to another embodiment of the present invention and a TSB packet header structure according to the method.

6 illustrates a SHB (Single Hop Broadcast) type geo-networking method and an SHB packet header configuration according to another embodiment of the present invention.

FIG. 7 illustrates a Geographically-Scope Broadcast (GBC) / Geographic-Scoped Anycast (GAC) type geo-networking method and a BC / GAC packet header according to another embodiment of the present invention.

FIG. 8 illustrates a beacon type geo-networking according to another embodiment of the present invention, and a beacon packet header according to the present invention.

FIG. 9 shows a structure of an LS (Location Service) request packet header and an LS response packet header according to an embodiment of the present invention.

FIG. 10 shows position vector information according to an embodiment of the present invention.

11 shows a packet forwarding method of a greedy forwarding algorithm according to an embodiment of the present invention.

12 illustrates a packet delivery method of a non-area contention-based algorithm according to an embodiment of the present invention.

13 shows a packet delivery method of an area contention-based algorithm according to an embodiment of the present invention.

14 shows service primitives, SDUs, and PDUs related to a geo-networking protocol according to an embodiment of the present invention.

FIG. 15 shows an example of use of a complaint, a request, and an indication through a service primitive according to an embodiment of the present invention.

16 shows parameters of GN-DATA.request according to an embodiment of the present invention.

FIG. 17 shows a repetition interval and a maximum repetition time according to an embodiment of the present invention.

18 shows a geo-networking transmission method according to an embodiment of the present invention.

19 shows a packet structure used in greedy forwarding according to an embodiment of the present invention.

20 shows a packet transmission method of greedy forwarding according to an embodiment of the present invention.

Figure 21 illustrates conform packet reception and packet repeat transmission in accordance with an embodiment of the present invention.

22 shows a packet transmission method of greedy forwarding according to another embodiment of the present invention.

23 shows a conform packet reception and packet repetition transmission according to another embodiment of the present invention.

24 shows a sender confirm packet according to an embodiment of the present invention.

25 shows a geo-networking transmission method according to an embodiment of the present invention.

26 shows a packet transmission method of the GUC according to the embodiment of the present invention.

27 shows a packet transmission method of greedy forwarding according to another embodiment of the present invention.

FIG. 28 shows a Destination Confidence packet according to another embodiment of the present invention. FIG.

29 shows a header type and a subheader type of a geo-networking packet according to an embodiment of the present invention.

30 shows a configuration of a V2X communication apparatus according to an embodiment of the present invention.

31 shows a flowchart of a geo-networking transmission method according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description with reference to the attached drawings is for the purpose of illustrating preferred embodiments of the present invention rather than illustrating only embodiments that may be implemented according to embodiments of the present invention. The following detailed description includes details in order to provide a thorough understanding of the present invention, but the present invention does not require all of these details. The present invention is not limited to the embodiments described below. Multiple embodiments or all of the embodiments may be used together, and specific embodiments may be used as a combination.

Most of the terms used in the present invention are selected from common ones widely used in the field, but some terms are arbitrarily selected by the applicant and the meaning will be described in detail in the following description as necessary. Accordingly, the invention should be understood based on the intended meaning of the term rather than the mere name or meaning of the term.

The present invention relates to a V2X communication device, wherein the V2X communication device is included in an Intelligent Transport System (ITS) system to perform all or some of the functions of the ITS system. V2X communication devices can communicate with vehicles and vehicles, vehicles and infrastructure, vehicles and bicycles, and mobile devices. The V2X communication device may be abbreviated as a V2X device. As an embodiment, the V2X device may correspond to an on-board unit (OBU) of a vehicle or may be included in an OBU. The OBU may also be referred to as OBE (On Board Equipment). The V2X communication device may correspond to an infrastructure's road side unit (RSU) or may be included in an RSU. The RSU may also be referred to as RSE (Road Side Equipment). Alternatively, the V2X communication device may correspond to the ITS station (ITS-S) or may be included in the ITS station. Any OBU, RSU, mobile device, etc. performing V2X communication may be referred to as an ITS station or a V2X communication device. In geo-networking communications, a V2X communications device may be referred to as a router.

The V2X communication device can communicate based on various communication protocols. The V2X communication device can implement IEEE 1609.1 ~ 4 Wireless In Vehicular Environments (WAVE) protocols. In this case, the V2X communication device may be referred to as a WAVE device or a WAVE communication device.

The V2X communication device can transmit a Cooperative Awareness Message (CAM) or a Decentralized Environmental Notification Message (DENM). The CAM is distributed in the ITS network and provides information about at least one of the presence, location, communication state, or operating state of the ITS station. DENM provides information about detected events. The DENM may provide information about any driving situation or event detected by the ITS station. For example, DENM can provide information on situations such as emergency electronic brakes, vehicle accidents, vehicle problems, traffic conditions, and so on.

Application layer: The application layer can implement and support various use cases. For example, the application may provide road safety, Efficient Traffic Information, and other application information.

Facilities layer: The facilities layer can support various applications defined at the application layer effectively. For example, the facility layer can perform application support, information support, and session / communication support.

Access layer: The access layer can transmit the message / data received from the upper layer through the physical channel. For example, the access layer may include an ITS-G5 wireless communication technology based on IEEE 802.11 and / or 802.11p standards based communication technology, a physical transmission technology of the IEEE 802.11 and / or 802.11p standard, a satellite / And can perform / support data communication based on 2G / 3G / 4G (LTE) / 5G wireless cellular communication technology, broadband terrestrial digital broadcasting technology such as DVB-T / T2 / ATSC, GPS technology and IEEE 1609 WAVE technology.

Network and Transport Layer: The network / transport layer can configure a network for vehicle communication between homogenous and heterogeneous networks by using various transport protocols and network protocols.

The transport layer is the link layer between the services provided by the upper layer (session layer, presentation layer, application layer) and lower layer (network layer, data link layer, physical layer). The transport layer can manage the transmission data to arrive at the destination exactly. At the transmitting end, the transport layer processes the data into packets of reasonable size for efficient data transmission, and at the receiving end, the transport layer can perform processing to recover the received packets back to the original file. As an example, protocols such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Basic Transport Protocol (BTP) may be used as the transport protocol.

The network layer manages the logical address and can determine the delivery path of the packet. The network layer can receive the packet generated at the transport layer and add the logical address of the destination to the network layer header. As an embodiment, the packet path may be considered for unicast / broadcast between vehicles, between vehicle and fixed stations, and between fixed stations. As an example, Geo-Networking, IPv6 support with mobility support, and IPv6 over geo-networking may be considered as networking protocols.

The ITS architecture may further include a management layer and a security layer.

The transport layer may generate BTP packets, and the network layer may encapsulate BTP packets to generate geo-networking packets. Geo-networking packets can be encapsulated in LLC packets. In the embodiment of FIG. 2, the data may comprise a message set, and the message set may be a basic safety message.

BTP is a protocol for transmitting messages such as CAM and DENM generated by the facility layer to the lower layer. The BTP header consists of A type and B type. The A-type BTP header may include a destination / destination port and a source port required for transmission / reception for interactive packet transmission. The B type header may include destination and destination port information required for transmission for non-interactive packet transmission. The fields / information included in the header are as follows.

Destination Port: The destination port identifies a facility entity corresponding to the destination of the data (BTP-PDU) contained in the BTP packet.

Source Port: A field created in the case of the BTP-A type, indicating the port of the protocol entity of the facility layer at the source from which the packet is transmitted. This field may have a size of 16 bits.

Destination Port Info: This field is created for the BTP-B type. It can provide additional information if the destination port is the best known port. This field may have a size of 16 bits.

A geonetworking packet includes a basic header and a common header according to a protocol of a network layer, and optionally includes an extension header according to a geo networking mode. The geo-networking header is described below again.

An LLC header is added to the geo-networking packet to generate an LLC packet. The LLC header provides a function to distinguish and transmit IP data from geo-networking data. IP data and geo-networking data can be distinguished by SNAP's Ethertype. As an embodiment, when IP data is transmitted, the Ether type may be set to 0x86DD and included in the LLC header. As an embodiment, if geo-networking data is transmitted, the Ether type may be set to 0x86DC and included in the LLC header. The receiver can identify the Ethertype field of the LLC packet header and forward and process the packet to the IP data path or the geo networking path according to the value.

3 (a) shows the basic header of the geo-networking packet header shown in Fig. 2, and Fig. 3 (b) shows the common header of the geo-networking packet header shown in Fig.

The basic header can be 32 bits (4 bytes). The basic header may include at least one of a version field, an NH field (Next Header), a LT (LifeTime) field, and a Remaining Hop Limit (RHL) field. Fields included in the basic header are described below. The bit size constituting each field is only an embodiment and may be changed.

Version (4-bit): The version field indicates the version of the geo-networking protocol.

NH (4 bits): NH (Next Header) field indicates the type of the following header / field. If the field value is 1, a common header is followed. If the field value is 2, a secured packet can be followed.

LT (8 bits): The LT (LifeTime) field indicates the maximum lifetime of the packet.

RHL (8 bits): The Remaining Hop Limit (RHL) field indicates the residual hop limit. The RHL field value can be reduced by one for each forwarding on the GeoAdhoc router. When the RHL field value reaches 0, the packet is no longer forwarded.

The common header can be 64 bits (8 bytes). The common header includes a Next Header (NH) field, an HT (HeaderType) field, a HST (Header Sub-Type) field, a TC (Traffic Class) field, a Flags field, a PayloadLength Or the like. The description of each field is as follows.

NH (4 bits): NH (Next Header) field indicates the type of the following header / field. If the field value is 0, it indicates an undefined "ANY" type, 1 indicates a BTP-A type packet, 2 indicates a BTP-B type packet, and 3 indicates an IP diagram of IPv6.

HT (4 bits): The header type field indicates the geo-networking type. Geo-networking types include Beacon, GeoUnicast, GeoAnycast, GeoBroadcast, Topologically-Scoped Broadcast (TSB), and Location Service (LS).

HST (4 bits): The header subtype field indicates the header type as well as the detailed type. As an example, when the HT type is set to TSB, a single hop is indicated when the HST value is '0', and a multi-hop can be designated when the HST value is '1'.

TC (8 bits): The traffic class field may include Store-Carry-Forward (SCF), Channel Offload (Channel Offload), and TC ID. The SCF field indicates whether to store the packet if there is no neighbor to which to transmit the packet. The channel offload field indicates that a packet can be delivered to another channel in the case of a multi-channel operation. The TC ID field is a value assigned at the time of packet forwarding in the facility layer and can be used to set the contention window value at the physical layer.

Flag (8 bits): The flag field indicates whether the ITS device is mobile or stationary, and may be the last one bit as an example.

PL (8 bits): The payload length field indicates the length of data, in bytes, following the geo-networking header. For example, in the case of a geo-networking packet carrying a CAM, the PL field may indicate the length of the BTP header and the CAM.

MHL (8 bits): The Maximum Hop Limit (MHL) field can indicate the maximum number of hops.

The geo-networking header includes the above-described basic header, common header, and extended header. The configuration of the extension header differs depending on the geo-networking type. Hereinafter, a header configuration according to each geo networking type will be described.

In this specification, a V2X communication device that performs geo-networking may be referred to as a router or a geo ad-hoc router. A V2X communication device that transmits geo-networking packets may be referred to as a source router or a sender. A V2X communication device that receives and forwards a geo-networking packet from a source router to a sander can be referred to as a forwarding router or forwarder. The V2X communication device, which is the final destination of the geo-networking packet, or the V2X communication device of the final destination area, may be referred to as a destination or destination router.

4 (a) shows a GUC (Geographically-Scoped Unicast) type data transmission method, and FIG. 4 (b) shows a GUC header structure.

GUC is a method of transferring data from a specific source router to a destination router. As shown in FIG. 4 (a), the source router S can transmit data to the destination router N8 via the multi-hop in the GUC type. The source router must have information about the destination router in its location table. If there is no information about the destination router, the source router can use the "LS request and LS reply" procedures to find the desired destination.

4 (b), the GUC packet header includes a basic header, a common header, and an extension header. The HT field of the common header indicates GUC, and the extension header includes an SN field, an SO PV (Source Position Vector) field, and a DE PV (Destination Position Vector) field. The description of the included fields is as follows.

SN (Sequence Number): The sequence number field indicates a value used for checking packet redundancy. The value of the sequence number field is incremented by one when transmitting packets from the source. In the receiving router, it is possible to determine whether or not to receive a packet by using a sequence number (or a sequence number and a TST value). SN is the value used for multi-hop transmission.

SO PV: Indicates the position of the source and can be a long position vector format.

DE PV: Indicates the location of the destination and can be a short position vector format.

5 (a) shows a TSB (Topologically Scoped Broadcast) type data transmission method, and Fig. 5 (b) shows a TSB header configuration.

The TSB is a broadcast scheme that adjusts the distance that data is transmitted by the number of hops. Location-based information is not used. Since the number of hops only determines the delivery of data, the location address of the destination or the area information to which the data is delivered is not used. Data can be forwarded from the source router (s) to all routers in the n-hop.

5 (a) shows data transmission of the TSB scheme of n-2. The source router broadcasts the signal by setting n = 2, and the routers within the transmission range of the source router receive this signal. Since N = 2, the forwarding routers N1, N2, and N3 receiving the data in one hop re-broadcast the received packet. Since N = 2, the routers receiving the re-broadcast signal do not re-broadcast the received packet. In this TSB transmission method, a single hop (n = 1) can be referred to as a single hop broadcast (SHB).

5 (b), the TSB packet header includes a basic header, a common header, and an extension header. The HT field of the common header indicates the TSB, and the extension header includes an SN field and an SO PV (Source Position Vector) field. The description of the included fields is as follows.

In the case of the TSB header, the number of transmissions is limited by the number of hops, so the destination address may be omitted.

FIG. 6A shows a data transmission method of SHB (Single Hop Broadcast) type, and FIG. 5B shows a SHB header configuration.

The SHB corresponds to a case in which the number of hops is 1 (n = 1) in the TSB described above. SHB packets are transmitted only to routers within the source router transmission range. Since data can be transmitted with the lowest latency, the SHB can be used for transmission of security messages such as CAM. Packets are transmitted only to the one-hop range routers N1, N2 and N3 of the source S as shown in FIG. 6 (a).

6 (b), the SHB packet header includes a basic header, a common header, and an extension header. The HT field of the common header points to the TSB, and the extension header contains an SO PV (Source Position Vector) field. The description of the included fields is as follows.

In case of SHB packet, the destination address can be omitted because the number of times of transmission is limited by the number of hops. Since the multi-hop transmission is not performed, the SN field for redundancy check can also be omitted.

FIG. 7A shows a GBC (Geographically-Scope Broadcast) / GAC (Geographically-Scoped Anycast) type data transmission method, and FIG. 4B shows a GBC / GAC header configuration.

GeoBroadcast / GBC is a transmission method that broadcasts packets to all routers in a certain area. GeoAnycast / GAC transmits packets to only one router that receives the first packet in a specific area. Transmission method. In the GBC, when the data transferred from the source router is delivered to a specific destination area, the packet is broadcast in a predetermined area. In the GAC, when a packet is delivered to one router in a specific destination area, the packet is no longer transmitted.

7 (b), the GBC / GAC header includes a basic header, a common header, and an extension header. The HT field of the common header indicates the GBC or the GAC, and the extension header includes an SN field, an SO PV (Source Position Vector) field, and destination area information. The destination area information includes a GeoAreaPosLatitude field, a GeoAreaPosLongitude field and a distance field (Distance a, b) and an angle field for indicating a range of the area.

8 shows a header configuration of a beacon packet. The beacon packet header includes a basic header, a common header, and an extension header, and the extension header may include SO PV information.

The beacon packet may be configured similar to the SHB packet header described above. The difference is that the SHB packet is used to carry data such as a CAM after which a message can be appended, and a beacon is used for the header itself without data being appended. CAM using SHB or beacon can be transmitted periodically. By transmitting and receiving the CAM or the beacon, the router obtains the location information of neighboring routers, and can perform routing using this location information. As an example, if the CAM is transmitted, the beacon may not be transmitted.

Fig. 9 (a) shows the LS request packet header, and Fig. 9 (b) shows the LS response packet header.

If there is no destination information in its location table, the source router can request geo-networking address information (GN_ADDR) for the destination in the vicinity. This address information request can be performed by transmitting an LS request packet (LS request) to the LS request packet. If the location table of the router receiving the LS request packet contains the information requested by the source router, the router can transmit LS response information (LS_reply). In addition, the router at the destination can transmit the LS response information to the LS request information.

The LS response information includes position vector information of GN_ADDR. The source router may update the location table via the LS response information. The source router can perform the GUC transmission by using the received geo-networking address information in response.

9 (a), the configuration of the LS request packet header is similar to the GUC header. In the LS request packet header, a geo networking address request field (RequestGN_ADDR) is included in place of the destination address field of the GUC header.

9 (b), the LS response packet header configuration is the same as the GUC packet header. However, the SO PV field includes the position vector information of the router, and the DE PV field includes the position vector information of the router that transmitted the request.

As described above, the geo-networking packet header includes a position vector (PV) field associated with a location. The types of position vectors include long PV and short PV. 10 (a) shows long position vector information, and FIG. 10 (b) shows short position vector information.

As shown in FIG. 10 (a), the long position vector information includes the following subfields.

GN_ADDR: The geo-networking address field can consist of a total of 64 bits. A geo ad-hoc router with geo-networking transport has a unique geo-networking address value. The geo-networking address field may include the following sub-fields.

a) M: Field to distinguish between geo networking address and manually set value. As an example, if the value is '1', it may be a manually set value.

b) ST: The ITS-S type field indicates the type of ITS station. The ITS-S type can be used for pedestrians, bicycle cyclists, mopeds, motorcycles, passenger cars, buses, light trucks, heavy trucks, trailers, special vehicles, , Trams, RSUs.

c) MID: As the V2X device identification information, the MAC address can be used.

TST (TimeSTamp): The Type Stamp field indicates the time at which the ITS station obtained the latitude / longitude value on the geo ad-hoc router. As a millisecond unit, a Universal Time Coordinated (UTC) value may be used.

LAT (Latitude), Long (Longitude): The latitude and longitude fields indicate latitude and longitude values of the geo ad-hoc routers.

PAI (Position Accuracy Indicator): Indicates the accuracy of geo ad-hoc router location.

S (Speed): Indicates the speed of the geo ad-hoc router.

H (Heading): Indicates the direction of the geo ad hoc router.

10 (b), the short position vector information includes a GN_ADDR field, a TST field, a LAT field, and a Long field. The description of each field is as described above for the long position vector.

Various packet forwarding methods can be used for geo-networking transport. For example, a greedy forwarding algorithm, a contention-based forwarding algorithm, a non-area contention-based forwarding algorithm, an area contention-based forwarding algorithm, an area advanced forwarding Algorithm or the like may be used. The forwarding algorithm is used to effectively transfer and distribute the data to the desired area. In the case of the greedy forwarding algorithm, the source router determines the forwarding router, and in the case of the contention-based forwarding algorithm, the receiving router determines whether to forward the packet using the contention. In the following, a V2X device / router that processes geo-networking algorithms may be referred to as an ego router.

In geo-networking, each V2X device performs the function of a router and can use an ad hoc method to determine the routing of the packet. Each V2X device transmits location information, speed information, and heading direction information of the vehicle around, and using this information, each V2X device can determine the routing of the packet. The information received periodically is stored in the LocT (Location Table) of the network & transport layer, and the stored information can be timed out after a certain period of time. LocT may be stored in a LocTE (Location Table Entry).

For geo-networking protocol operation, each ad hoc router must have information about the other ad hoc routers. Information about the neighboring routers may be received via SHB or beacon packets. Routers can update LocT when new information is received. The transmission period of the SHB or the beacon packet may be changed according to the channel state. The location / location table may also be referred to as LocT.

Information about the neighboring routers is stored in the LocT, and the stored information may include at least one of the following information. The information stored in the LocT may be deleted from the list when the lifetime set in the soft-state state has expired.

GN_ADDR: Geo-network address of ITS station

Type of ITS-S: Indicates the type of ITS station, for example, vehicle or RSU.

Version: Geo-networking version used for ITS station

Position vector PV: The position vector information includes geographical position information, velocity information, heading information, time stamp information indicating the position information measurement time, position accuracy indicator (PAI) information indicating the accuracy of the position providing information Or the like.

Flag LS_PENDING (LS_PENDING flag): A flag indicating when a location service request is in progress because the current LocT does not have an address for the destination

FLAG IS_NEIGHBOUR (IS_NEIGHBOUR flag): A flag indicating whether there is a geo ad-hoc router capable of communicating within communication range

DPL: Duplicate Packet List for source GN_ADDR

Type Stamp: The time stamp of the last packet indicating the end of duplication

PDR (Packet Data Rate): Packet data rate to be maintained in geo ad hoc routers

The greedy forwarding algorithm determines which of the neighbor routers the sander will know about to forward the packet to. The LocT (Locator Table) of the sander can be updated to the latest value through a periodically distributed SHB or beacon packet. The sander selects the router closest to the destination from the LocT, which allows the packet to be delivered to the destination with the least number of hops.

11, routers 1 to 5 exist in the communication range of the source router. The source router transmits the packet by setting the MAC address of the router 2 closest to the destination to the link layer destination address.

The Greedy Forwarding Algorithm does not use buffering, and can forward a packet to its destination as fast as it can without breaking the connection between routers. However, if the connection between the routers is lost, that is, if the router to which the next hop is to be transmitted deviates from the transmission range or disappears, the reliability of the packet can not be transmitted.

Hereinafter, a packet delivery method of a contention-based forwarding algorithm will be described.

The contention-based forwarding algorithm determines, by contention, whether the receiver will forward the packet, unlike the greedy forwarding algorithm described above. Any receiver that receives a packet broadcast by the sander can be a potential forwarder. The receiver sets its own timer according to the distance, and the receiver whose timer has expired first forwards the packet. If the receiver does not receive a packet from other receivers until the timer expires, the receiver forwards the packet when the timer expires. If a packet is received before the timer expires, the receiver will turn its timer off and will not forward the packet.

Contention-based forwarding algorithms do not need to know the location of neighboring routers, unlike the greedy forwarding algorithm. The packet forwarding can be performed even if the SHB packet or the beacon packet is not periodically transmitted, i.e., the location table is not present. Since there are a plurality of candidate forwarders, the reliability may be high and the probability of delivering packets to the destination may be high. However, buffering time is required for packet delivery and latency may increase. In addition, additional buffer usage is required.

Non-area contention-based algorithms are used to deliver packets in the destination direction. In Fig. 12, the source router S may broadcast packets for packet transmission. Routers (1 to 5) within the communication range of the source router receive the packet. Of routers, only the router closest to the destination can be a forwarding candidate. In Fig. 12, the routers 1-3 can be forwarder candidates.

Forwarder candidates can store the received packet in a Contention-based Forwarding (CBF) packet buffer and set a timer. The timer can be set to a smaller value as the distance from the source increases. In Fig. 11, the timer of the router 1 can be set to 25 ms, the timer of the router 2 to 10 ms, and the timer of the router 3 to 20 ms, respectively. When the timer expires, the router broadcasts the buffered packet.

Router 2, whose timer expires first, broadcasts the packet. Router 1 and Router 3, which have received the packet broadcasted by Router 2, stop their timer and delete the packet stored in the buffer. However, if Router 2 disappears or if Router 1 and Router 3 do not exist within the communication range of Router 2, the timers of Router 1 and Router 3 are still valid, and thus the router that broadcasts the packet first becomes a timer of 0.

The area contention-based forwarding algorithm aims at efficiently spreading data in a certain area. Therefore, there is no fixed destination and the timer setting can be determined only considering the distance from the source. The area contention based algorithm is performed when the router belongs to a specific area, and it is aimed at rapidly distributing / transmitting information within the area.

In Fig. 13, a packet broadcasted by the source router S is transmitted to the routers 1 to 6. Router 2, which is farthest from the source router, broadcasts the packet first, and Router 1 and Router 3, which receive it, stop the timer and do not forward the same packet.

Routers

4 and 6 do not receive packets forwarded by router 2. Therefore, routers 4 to 6 operate their respective timers and broadcast received packets when the timer expires. When the router 5 forwards the packet, the router 4 that has received the packet ends its timer and removes the packet being prepared for transmission from the buffer. Router 6, which has not received the packet forwarded by another router, forwards the packet when its timer expires. In the case of the area contention-based algorithm, the source router can quickly forward and share packets in a certain area in all directions.

In addition to the embodiments of Figures 12 and 13, an area advanced forwarding algorithm may be used. The area advanced forwarding algorithm is an algorithm that operates by combining the above-described greedy forwarding algorithm and contention-based forwarding algorithm. Area advanced forwarding algorithms, such as contention-based forwarding algorithms, use packet-forwarding algorithms to route packets in certain directions to minimize delays, while contention-based forwarding methods are used to increase delivery efficiency .

A forwarding algorithm that delivers packets to a specific destination area is called a non-area algorithm. Non-region algorithms include greedy forwarding algorithms and non-area contention-based forwarding algorithms. An algorithm for distributing data around a specific area is called an area-forwarding algorithm. The area-forwarding algorithm includes a simple geo-broadcast forwarding algorithm, an area contention-based forwarding algorithm, and an area advanced forwarding algorithm.

In the following paragraphs, we describe a more efficient method of transmitting geodetic networks according to the greedy algorithm.

In the architecture of the IEEE 802.11p network, three types of Basic Service Set (BSS), Independent BSS (IBSS) and Extended Service Set (ESS) are defined as SS (Service Set) do. Among these, the IBSS is composed of stations (STAs) which generally do not have an infrastructure called an ad-hoc network, and the BSS includes an access point (AP) operating as a controller / master STA. An ESS is a combination of two or more BSSs connected by a distribution system (DS). Looking at the relationship between them, a STA in an IBSS acting as a controller or an access point (AP) in the BSS periodically broadcasts a beacon containing a service set ID (SSID) and other information. Another STA in the Service Set (SS) receives the beacon and synchronizes time and frequency based on the beacon.

STAs can communicate with each other only if they are members of the same SS, and these same SS architectures can be used for WAVE applications. However, shaping the SS requires multiple steps, including time and frequency synchronization, authentication and association, which results in an unacceptable time delay in some safety applications such as vehicles. In the case of a vehicle, a plurality of vehicles can be included in each wireless link for less than a second. Therefore, OCB (Outside the Context of a BSS) mode is applied to minimize the message waiting time so as to be suitable for vehicle communication. The OCB mode is applied to two or more devices within a service area of a single wireless link, and an STA in OCB mode can configure and transmit any SD and data and control frames at any time the member knows. While there is an advantage of low latency, OCB mode does not receive authentication, connection or data confidentiality services at the MAC layer, and equivalent services in WAVE have been partially moved to higher layers defined in IEEE 1609.2.

802.11p OCB mode guarantees low latency but does not support interoperability. There is no way in the MAC layer to ensure that intercommunication has been successfully performed.

The Service Access Points (SAP) connected to the networking / transport layer are shown in FIG. Each SAP sends and receives service primitives of request / request and confirm / confirm. For example, when requesting a network layer that is a sublayer of sending a geo-networking packet from a transport layer, the service primitive GN_DATA.request is used via GN-SAP. The network layer receiving the GN-DATA.request generates a geo-networking packet according to this information and delivers it to the LLC layer through IN-SAP. It informs the upper layer through the CONFIRM primitive whether the requested packet can be sent or not. If a packet is received, GN-DATA.indication can be delivered to the upper layer.

As shown in FIG. 15, the ge-networking layer receiving the GN-DATA request transmits geo-networking packets to the LLC layer through IN-SAP. Whether or not the request packet can be sent is notified to the upper layer through the CONFIRM primitive. When a packet is received, GN-DATA.indication is delivered to the upper layer.

Among the parameters shown in FIG. 16, whether to transmit the same packet several times can be determined by a repetition interval and an maximum repetition time.

The upper layer of the geo-networking protocol determines and delivers two parameter-repetition interval and maximum repetition time for packet delivery. The repetition interval represents the time interval (ms) in which the same geo-networking packet is repeatedly transmitted for the maximum repetition time. This value is an optional value, and if not used, the packet transmission is not repeated. The maximum repetition time indicates the period (ms) in which the packet is repeated when the repetition interval is set. If the repeat interval is not used, the value of the maximum repeat time is also omitted. The maximum repetition time parameter performs a function to receive data to disseminate when a new router enters the transmission area. Also, the maximum repetition time parameter may be set in preparation for path loss in data forwarding. Upon receipt of these parameter values and messages from the facility layer, the geo-networking layer generates geo-networking packets by repeating the received data for each repetition interval for a maximum repetition time.

As described above, the geo-networking header includes a sequence number field. A geo ad hoc router can receive multiple copies of the same packet in the course of a plurality of hops. This can be referred to as packet duplication. Packet duplication can occur when packets are forwarded from multiple routers, when a routing loop occurs, or when a router malfunctions. When a duplicate packet is received, a sequence number is used to eliminate it.

The sequence number is used only for a multi-hop packet (GUC, TSB, GBC, GAC, LS Request, LR Reply) and may not be included in a single-hop packet (beacon, SHB). The value of the sequence number is incremented by 1 each time a multi-hop message is generated on the source router. As an example, 2 ^ 16-1 sequence numbers may be generated. Different sequence numbers are applied to the packets repeatedly generated even when packets having the same content are generated on the basis of the repeat interval for the maximum repeat time described above.

The router receiving the packet including the sequence number information may perform packet duplication detection. The router generates a sequence number list received by the address of the source router, and can check duplication through this list. For example, the router can compare the source address of the received packet with the DPL (Duplication Packet List) of the location table to determine duplication.

As described above, the greedy forwarding algorithm determines which of the known neighboring routers will forward the packet. The location table in the sender is updated to the latest value via a periodically transmitted SHB or beacon packet. Among the routers included in the sender's location table, the router closest to the destination is selected as the forwarder, so that packets can be delivered to the destination with the least number of hops. In the case of the greedy forwarding algorithm, packets can be forwarded quickly to the destination unless the connection between the forwarding routers is broken. However, if the connection between the forwarding routers is broken, the packet may not be delivered. For example, if the router that will deliver the next hop is out of range or disappears, there is no way to forward the packet, which reduces reliability. However, the sender router can respond to a path loss in which the forwarding router temporarily disappears by repeatedly transmitting the same packet.

When a packet is transmitted through a multi-hop, the probability of occurrence of path loss can be reduced by repeatedly transmitting the same packet. However, channel efficiency is inefficient because the same data overlap and occupy the channel. In addition, it is difficult to determine the number of repetitions to increase the packet delivery probability. Therefore, we propose a method to efficiently use the channel by using the conform packet in the multi-hop transmission. The present invention proposes a method for informing a forwarder / forwarder router that a packet has been received that a packet has been received to a sender router. In addition, the present invention proposes a method of notifying that a destination router has received a packet to an original packet generation router.

In the multi-hop transmission using the greedy forwarding method, the sander can receive and confirm the packet transmitted by the forwarder in order to check whether the forwarder has transmitted the packet transmitted by the forwarder. When a packet identical to the transmission packet is received from the forwarder, the sander can confirm that the forwarder has received and transmitted the packet. However, in case of the greedy forwarding algorithm, the router marks the destination address in the last MAC address and transmits the packet. And the router can not receive and decode the packet unless the destination address is its own address. Accordingly, the present invention proposes a method of efficiently using a channel by increasing reliability and reducing the number of packet repetition transmissions in a packet forwarding method using a greedy forwarding algorithm. The present invention proposes a case in which a conform packet is transmitted to a sender in a multi-hop transmission and a case where a complete packet is transmitted in a destination.

1. Use of Sender Confidence Packets

FIG. 18 shows an embodiment in which a geo-networking transmission is performed to notify a nearby vehicle of an accident or a road hazard when a vehicle traveling on a road is operated. In the case of Fig. 18, the source router need not know whether or not the message reaches the destination. The source router can repeat the message multiple times, taking into account the path loss regardless of whether the forwarding message arrives at the destination well.

When the vehicle delivers a road condition as shown in FIG. 18, the responsibility for transmitting the packet is transferred to each router corresponding to the forwarder together with the packet transmission. Therefore, the mode that informs the previous forwarder or the source router that the packet has been received is defined as the confirm_sender mode. The forwarder or source that transmitted the received packet corresponds to the transmitting router / sender router in the case of the receiving router.

In the case of greedy forwarding, the access layer includes a DSAP field and an SSAP field, and the payload contains a geo-networking packet. The geo-networking packet includes a base header, a common header, and an extended header. The description of each header is as described above.

When the same data is repeatedly transmitted in the multi-hop operation, the transmission router can transmit multi-hop packet GUC, GBC, GAC, LS request, LS response. In Greedy Forwarding, a router selects a router closest to a destination in a location table including information on the locations, speeds, directions, and the like of neighboring routers, and transmits the MAC address of the router to an access layer packet To the destination address of the MAC header of the MAC header.

The router generates a packet (S20010). The generated packet may be received at the upper layer and generated, or may be the packet forwarded from another router.

The router can determine whether to forward the packet (S20020). When a packet is forwarded to the geo-networking layer, the type of forwarding of the packet can be determined in the upper layer. If the packet is a forwarded packet from another router, the packet forwarding method / method can be determined by the packet transmission type included in the header of the packet. The router can decide to forward the packet if the transport packet type corresponds to one of GUC, GBC, GAC, LS request, or LS response requiring multi-hop transmission.

If the packet is not a forwarded packet, the router may broadcast the packet in a single hop or discard the packet (S20030). The router examines the packet type described above, and in the case of an SHB packet, the packet can be single-hop broadcasted. Also, the router can check the duplication of the packet and discard the packet if the packet is a duplicate packet.

The router can transmit the packet (S20040). Routers can send packets using a greedy forwarding algorithm. The transmission method according to the greedy forwarding algorithm is as described in FIG. In other words, the router retrieves the forwarder from the location table and transmits the packet according to the greedy forwarding to the retrieved forwarder. The router determines the router closest to the destination in the location table as a forwarder, and transmits the packet by setting the MAC address of the router to the destination address of the packet.

The router operates according to receipt of the conform packet (S20050). The router sets the wait time (T_wait) and waits for the receipt of the acknowledgment packet during the waiting time. When a conform packet is received within the waiting time, the router does not repeatedly transmit the packet.

When the wait packet is not received and the wait time is terminated (S20060), the router confirms the maximum number of iterations N (S20070). If the number of packet transmissions does not exceed the maximum number of iterations (N), the router retransmits the packet. If the packet transmission count exceeds the maximum number of repetitions (N), the router discards the packet (S20080). The maximum number of repetitions of a packet can be set differently depending on the channel condition or the lifetime of the packet.

Fig. 21 (a) shows packet repetition transmission of the router described in Fig.

In Fig. 21 (a), the router retransmits the same packet for each repetition interval for the maximum repetition time. In the embodiment of Fig. 21 (a), the router transmits the same packet seven times.

Fig. 21 (b) shows a packet repetitive transmission of a router when a conform packet is used.

In the case of FIG. 21 (b), as described in FIG. 20, the router waits for a conform packet for a waiting time (T_wait) after packet transmission. As shown in FIG. 21 (b-1), when the router receives a conform packet before the first waiting time, it does not retransmit the same packet any more. As shown in FIG. 21 (b-2), if the CONFESS packet is not received during the first waiting time, the router transmits the same packet and again waits for the reception of the CONFESS packet during the second waiting time. If a CONFIRM packet is received before the second waiting time has elapsed, the router stops transmitting the packet repeatedly. By using a conform packet in the embodiment of FIG. 21 (b), up to six repetitive transmissions can be omitted compared to FIG. 21 (a). However, since a conform packet must be transmitted and received, it is more advantageous to use the channel by repeatedly transmitting the number of times less than half of the predetermined number of repetitions. Therefore, in the case of FIG. 21 (b), the maximum number of repetitions may be set to 3 or less. However, since the size of the conform packet can be smaller than the transmission packet, the efficiency can still be increased in terms of channel usage.

As an embodiment, the upper layers of the geo-networking layer can provide information on the repetition transmission and the maximum repetition time. As an example, instead of repeating transmission at intervals of repetition interval, the router may try to repeat transmission until it receives a confirm packet within the maximum repetition time.

Depending on the maximum number of iterations, it can be determined how many times the packet is repeatedly transmitted over the maximum iterative time. The maximum number of iterations can be determined according to the following equation (1) based on the CBR (Channel Busy Ratio) value.

The V2X device communicates in an ad hoc network based on 802.11. In ad hoc networks, DCC (Decentralized Congestion Control) can be used to stabilize system operation and to distribute traffic on specific frequency channels. CBR (Channel Busy Ratio) information can be exchanged between adjacent devices to effectively operate the DCC algorithm and provide network robustness. The present invention may refer to ETSI TS 102 636-4-2 v.1.1.1 for CBR information. The CBR information may include local CBR information measured and obtained by itself and remote CBR information obtained from the neighboring vehicle.

CBR (Channel Busy Ratio) represents a time-dependent value between 0 and 1, indicating a fraction of time that the channel is busy. Local CBR (Local Channel Busy Ratio) is a CBR that is perceived locally by a particular ITS station and represents a time-dependent value of 0 to 1, inclusive.

If the current CBR is larger than CBR_max, the router may not perform iterative transmission or it may repeat transmission / forwarding only once. If CBR is less than CBR_max, iterative transmission may be performed by a certain integer value in inverse proportion to CBR. As an embodiment, since the present invention considers transmission of a conform packet, the N value can be obtained by using the CBR which is twice higher than the current CBR. The waiting time T_wait can be obtained by dividing the predetermined maximum repetition time by the N value. The waiting time T_wait may be determined by influencing the CBR, and may be set to a larger value as the channel is busy and a smaller value as the channel is less busy. As shown in Equation (1),? May be set according to the channel status or the system setting to determine the maximum number of transmissions.

22 is a modified example of the packet retransmission determination portion in the embodiment of Fig. 20, and the same description of the same step / operation as that of Fig. 20 is omitted. In the case of the embodiment of FIG. 22, the steps S20010 to S20040 of FIG. 20 are applied equally to the steps S22010 to S22040.

In the embodiment of FIG. 20, the router waits for a waiting time after the packet transmission, and retransmits the packet if the conform packet is not received. On the other hand, in the embodiment of FIG. 22, the router repeatedly transmits a packet according to the repetition interval, but stops repeating when a conform packet is received. Although not shown in FIG. 22, the router transmits the packet based on the set repetition interval. The router's geo-networking layer can receive them from the upper layer by receiving the repetition interval and the maximum repetition time. As described in the embodiment of FIG. 17, the router performs the greedy forwarding transmission for each repetition interval for the maximum repetition time.

When the CONFIRM packet is received (S22060), the router terminates the repeated transmission of the packet. If no confirm packet is received (S22060), the router confirms whether it is within the maximum repeat time (S22070). If no acknowledgment packet is received and the maximum iteration time has not elapsed, the router retransmits the packet. If the maximum repeat time has elapsed with no acknowledgment packet being received, the router discards the packet (S22080). The router discards the packet (S22080), and starts transmission of another packet.

The router repeatedly transmits the same packet at each repetition interval within the maximum repetition time. However, when the router receives the CONFIRM packet from the forwarder, the same packet repetition transmission after the reception time is ended.

In the packet repetition transmission method using the above-described confirm packet, the SN (Sequence Number) of the repeatedly transmitted packets can be set to the same value. As an example, the sequence numbers of repeatedly transmitted packets may not be the same. It is not guaranteed that the packets are transmitted in the order of the sequence numbers in the vehicle ad hoc network. In addition, the sequence number used in geo-ad hoc network is used to identify a packet in the network layer rather than to indicate the order of the packet. That is, a sequence number is used for the purpose of removing a redundancy packet that may occur in an ad hoc network operation or a same packet due to a broadcast storm / loop. Therefore, although the sequence numbers of the duplicated packets may be different, in the embodiment of the present invention in which duplicate transmissions are performed using the conform packet, the duplicate transmission packets have the same sequence number.

When using a conform packet, the number of iterations can be reset in the forwarder. The sander router that received the CONFIRM packet from the forwarder during multi-hop is no longer required to retransmit the same packet. The need for retransmissions is transferred to the forwarder that received the packet. The overall transmission process is multi-hop, but the transmission of each router corresponds to single-hop. Therefore, repeated packets do not need to have different SNs in terms of sending a consult message. The number of iterations can be set differently by the forwarder depending on the channel conditions.

FIG. 24 is a CONFIRM packet transmitted by the forwarding router to the sender router, and may be referred to as a CONFIRM_SENDER packet or a sender / sender conform packet. 24 is encapsulated at the MAC layer, and the destination address of the MAC packet header is set to the MAC address of the sender router determined in the greedy forwarding algorithm. The basic configuration of the packet is similar to the geo-networking packet described above, and the same configuration will not be described again. Sender Confirmation Packets are sent in a single hop.

The "CONFIRM" type is added to the HT (Header Type) field of the common header.

The Received SN (Receive SN) field indicates the sequence number of the packet received from the sender router. The forwarding router copies the sequence number (SN) of the received message to the received SN field to indicate which of the received messages it is conforming to.

The CONFIRM_STATUS field indicates whether the packet can be forwarded. The CONFORMATION status field can indicate why forwarding is possible or impossible if forwarding is not possible. Reasons for the inability to forward can be indicated by code for reasons such as i) no traffic around, ii) impossible due to an internal state such as a full buffer, and iii) unable to forward in CBR saturation.

The forwarder can forward the message to the sender, then forward the message to the sender that forwarding is possible. The forwarder can forward packets to the forwarder closest to the destination in greedy forwarding.

The sander may not receive the sender confirm packet, or the sender confirm packet may be received but the forwarding is not possible. In this case, under the condition that retransmission is possible, the sender tries forwarding again. The sender can send a packet to a forwarder other than the forwarder to increase the transmission probability. For example, the sender may select a router that is less than the destination of the router as the forwarder and send the packet to the router. The sender can select another forwarder based on the reason of the agreed status field.

2. Use of Destination Confidence Packets

Fig. 25 shows a case where the source router desires to know whether or not a destination of a transmission message has arrived. This relates to Quality of Service (QoS) of transmission data, and the embodiment of FIG. 13 shows an example of GUC transmission. That is, when the source router confirms that the packet arrives at the destination, the source router can terminate the repeated transmission of the same packet.

In the embodiment of FIG. 25, unlike the case of the sender confirm packet, the router of the final destination area transmits the confirm packet / message to the source router in multi-hop. This CONFIRM packet can be referred to as a CONFIRM_DESTINATION packet.

The router generates a packet (S26010). The generated packet may be received at the upper layer and generated, or may be the packet forwarded from another router.

The router can determine whether to forward the packet (S26020). When a packet is forwarded to the geo-networking layer, the type of forwarding of the packet can be determined in the upper layer. If the packet is a forwarded packet from another router, the packet forwarding method / method can be determined by the packet transmission type included in the header of the packet. The router may decide to forward the packet if the transport packet type corresponds to GUC.

For GBC, GAC, there is no specific destination address. For the LS request / LS response, there is also no specific destination address. If the LS request requires a specific geo address, any router knowing the location information for the requested address can inform the source router of the location information. The TSB scheme may be used for the LS request, and the GUC may be used for the LS response. However, even in the case of the LS response, the above-described sender confirm packet may be more suitable for use than the destination confirm packet. Thus, the embodiment of the destination conform packet can be used when the transmission packet type is GUC.

If the router is not a packet to be forwarded, the packet may be broadcasted in a single hop or discarded (S26030). The router examines the packet type described above, and in the case of an SHB packet, the packet can be single-hop broadcasted. Also, the router can check the duplication of the packet and discard the packet if the packet is a duplicate packet.

The router can transmit the packet (S26040). Routers can send packets using a greedy forwarding algorithm. The transmission method according to the greedy forwarding algorithm is as described in FIG. In other words, the router retrieves the forwarder from the location table and transmits the packet according to the greedy forwarding to the retrieved forwarder. The router determines the router closest to the destination in the location table as a forwarder, and transmits the packet by setting the MAC address of the router to the destination address of the packet.

The router operates according to receipt of the conform packet (S26050). The router sets the wait time (T_wait) and waits for the receipt of the acknowledgment packet during the waiting time. When a conform packet is received within the waiting time, the router does not repeatedly transmit the packet.

When the wait packet is not received and the wait time is terminated (S26060), the router confirms the maximum number N of repetitions (S26070). If the number of packet transmissions does not exceed the maximum number of iterations (N), the router retransmits the packet. If the number of packet transmissions exceeds the maximum number of repetitions (N), the router discards the packet (S26080). The maximum number of repetitions of a packet can be set differently depending on the channel condition or the lifetime of the packet.

The waiting time may be a value larger than the waiting time of the embodiment of FIG. This is because a longer time may be required to receive the conform packet from the destination to the multi-hop after the packet transmission. The router can variably determine the length of the waiting time by predicting the number of hops. The number of repetitive transmissions can be determined within a range that does not exceed the maximum repetition time determined at the upper layer of the source router. The number of repetitive transmissions may be determined according to the state of the channel regardless of the maximum number of repetitions.

27 shows an embodiment in which the packet retransmission determination part is modified in the embodiment of FIG. 26, and description of the same steps / operations as those of FIG. 27 is omitted. In the case of the embodiment of FIG. 27, the description of steps S26010 to S26040 of FIG. 26 applies equally to the steps S27010 to S27040.

In the embodiment of FIG. 27, the router waits for a waiting time after the packet transmission, and retransmits the packet if the conform packet is not received. On the other hand, in the embodiment of FIG. 27, the router repeatedly transmits a packet according to the repetition interval, but stops repeating when a conform packet is received. Although not shown in FIG. 27, the router transmits the packet based on the set repetition interval. The router's geo-networking layer can receive them from the upper layer by receiving the repetition interval and the maximum repetition time. As described in the embodiment of FIG. 17, the router performs greedy forwarding for each repetition interval for a maximum repetition time.

When the CONFIRM packet is received (S27060), the router ends the repeated transmission of the packet. If the CONFIRM packet is not received (S27060), the router confirms whether it is within the maximum repetition time (S27070). If no acknowledgment packet is received and the maximum iteration time has not elapsed, the router retransmits the packet. If the maximum repetition time has elapsed with no acknowledgment packet being received, the router discards the packet (S27080). The router discards the packet (S27080), and starts transmission of another packet.

Fig. 28 is a CONFIRM packet transmitted by a destination router to a sander router, and may be referred to as a CONFIRM_DESTINATION packet or a destination-conform packet. 28 is encapsulated at the MAC layer, and the destination address of the MAC packet header can be set to the MAC address of the source router. The basic configuration of the packet is similar to the geo-networking packet described above, and the same configuration will not be described again. The Sender Confidence packet can be sent in either single-hop or multi-hop. A description of the fields included in the packet is as follows.

SN field: The sequence number field / information indicates the sequence number (SN). The destination router can forward the conform packet to the source router in multi-hop mode. Sequence number information can be used to detect the redundancy of the destination conform packet.

Received SN (Receiveed SN) field: The received SN field indicates the sequence number of the packet received from the source router. With this value, the source router can confirm that the transmitted packet arrives at the destination, and can determine that there is no need for redundant transmission for the packet.

RN (Redundancy Number) field: The RN field indicates how many times the same packet transmitted from the same source router arrived at the destination. The RN field may also be referred to as duplication frequency information. The value of the RN field may be a value for the currently negotiated packet or a value for the previously received packet. This field can be used to determine how many retransmissions the source router will attempt to send the packet to its destination. Considering efficient use of channels, it may be desirable to set the number of duplicates to one. The source router that has received the RN information can determine whether it is repeating the packet an appropriate number of times. For example, if a plurality of conform packets include a high value RN field, the source router may reduce the number of redundant transmissions.

The SO PV field indicates the position vector of the destination router transmitting the destination conform packet.

The DE PV field indicates the source router's position vector.

The SO PV field may be referred to as source position vector information, and the DE PV field may be referred to as destination position vector information, respectively.

In order to use the conform packet according to the present invention, the geo-networking layer can additionally receive the maximum repetition time information when receiving the GN-DATA.request from the upper layer.

A header type and a subheader type may be added to the HT field and the HST field of the common header shown in FIG. 3, as shown in FIG.

If the header type is geo unicast, Normal, CONFIRM_SENDER, and CONFIRM_DESTINATION can be added as the header subtype. The normal type indicates the case of using the repetition interval and the maximum repetition time without using the conform packet in the case of repetitive transmission. If the header type is geo unicast and the subheader type is sender conform (that is, in the case of GEOUNICAST_CONFIRM_SENDER), the forwarder is requested to receive the sender conform packet. The forwarder that receives the packet including this header transmits the sender confirm packet to the sander that transmitted this packet. The sender router which received the sender confirm packet confirms that the packet has been delivered to the forwarder, so it stops the repeat transmission. If the header type is geo unicast and the subheader type is destination conform (ie, GEOUNICAST_CONFIRM_DESTINATION), the destination router is requested to receive the destination conform packet. The router at the final destination receiving the packet containing this header transmits the destination conform packet to the source router that transmitted this packet. The source router which receives the destination confirm packet confirms that the packet has been delivered to the destination, so it stops the repeated transmission. End-to-end packet transmission can be confirmed. Therefore, when requesting a destination conform packet, more reliable packet transmission / reception can be assured compared to a sender conform packet.

If the header type is geo unicast / geo-broadcast, a header subtype requesting a sender conform packet may be added. That is, header subtypes of sender conform can be added. When a packet is transmitted with the added type, the forwarder router that receives it sends a sander confirm packet to the sender router that sent the packet.

You can add CONFIRM to the header type to use a packet that confirms to the sander or source that it has received a multi-hop transport packet. A CONFIRM_SENDER and a CONFIRM_DESTINATION header subtype can be added.

In Fig. 30, the V2X communication device 30000 may include a communication unit 30010, a processor 30020, and a memory 30030.

The communication unit 30010 can be connected to the processor 30020 to transmit / receive radio signals. The communication unit 30010 can upconvert the data received from the processor 30020 to the transmission / reception band and transmit the signal or downconvert the reception signal. The communication unit 30010 may implement the operation of at least one of a physical layer and an access layer.

The communication unit 30010 may include a plurality of sub RF units for communicating in accordance with a plurality of communication protocols. As an example, the communication unit 30010 may be an ITS-G5 wireless communication technology based on physical transmission techniques of DSRC (Dedicated Short Range Communication), IEEE 802.11 and / or 802.11p standards, IEEE 802.11 and / Data communication based on 2G / 3G / 4G (LTE) / 5G wireless cellular communication technology including broadband wireless mobile communication, broadband terrestrial digital broadcasting technology such as DVB-T / T2 / ATSC, GPS technology and IEEE 1609 WAVE technology Can be performed. Communication unit 30010 may comprise a plurality of transceivers implementing each communication technique.

The processor 30020 may be connected to the RF unit 30030 to implement the operation of the layers according to the ITS system or the WAVE system. Processor 30020 may be configured to perform operations in accordance with various embodiments of the present invention in accordance with the above figures and description. Also, at least one of the modules, data, programs, or software that implement the operation of the V2X communication device 30000 according to various embodiments of the present invention described above may be stored in the memory 30010 and executed by the processor 30020 have.

The memory 30010 is connected to the processor 30020 and stores various information for driving the processor 30020. [ The memory 30010 may be included inside the processor 30020 or installed outside the processor 30020 and connected to the processor 30020 by a known means.

The processor 30020 of the V2X communication device 30000 can perform the geo-networking packet transmission described in the present invention. The geo-networking packet transmission method of the V2X communication apparatus 30000 will be described below.

The V2X communication device can determine the forwarder from the location information and set the address of the determined forwarder to the link layer address (S31010).

The V2X communication device can transmit the geo-networking packet based on the above-described Greedy algorithm. The V2X communication device can determine the forwarder based on the location table, i.e., the distance between the neighboring V2X communication devices included in the location information and the destination. That is, the V2X communication apparatus closest to the destination among neighbor V2X communication apparatuses included in the location table can be determined as a forwarder. To forward the packet to the forwarder, the address of the forwarder may be set to the link layer address of the geo-networking packet. The location information includes information about at least one neighbor V2X communication device executing a geo-networking protocol. As described above, the location information may include at least one of geo network address information, link layer address information, type information, position vector information, or SCH information for at least one neighboring V2X communication apparatus that has received the geo networking packet from the V2X communication apparatus .

The V2X communication apparatus can transmit the geo-networking packet (S31020).

The V2X communication device can transmit the geo-networking packet based on the set link layer address. That is, the V2X communication device can transmit the packet to the determined forwarder.

The V2X communication apparatus may retransmit the geo-networking packet at a specific time interval until the maximum repetition time ends (S31030). The specific time interval may correspond to the above-described repeat interval or wait time. The embodiment of the repetition interval or the waiting time is as described above.

The V2X communication apparatus can terminate the retransmission of the geo-networking packet when receiving the conform packet from the forwarder. A conform packet may correspond to a sender conform packet in which the forwarder confirms receipt of the geo networking packet. Alternatively, the conform packet may correspond to a destination conform packet in which the destination V2X communication device conforms to reaching the destination region of the geo-networking packet.

As shown in FIG. 24, the sender confirm packet may include at least one of the received sequence number information or the conform status information. The received sequence number information may have the same value as the sequence number information of the transmitted geo-networking packet. The conform status information may indicate whether the forwarder is capable of forwarding the genino networking and if the forwarding is not possible.

As shown in FIG. 28, the destination confirm packet may include at least one of sequence number information, received sequence number information, and duplication count information. The sequence number information may indicate the sequence number of the destination conform packet. The received sequence number information may have the same value as the sequence number information of the transmitted geo-networking packet. The number of times of duplication can indicate the number of times the same packet reaches the destination. The destination conform packet may further include source position vector information and destination position vector information. The source position vector information represents a position vector of a destination V2X communication apparatus that transmits a destination conform packet. The destination position vector information may represent a position vector of a source V2X communication apparatus that multi-hop transmits a geo networking packet.

The sender-conform packet may correspond to a single-hop packet. The destination conform packet may correspond to a multi-hop packet.

The embodiments described above are those in which the elements and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

Embodiments in accordance with the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) field programmable gate arrays, processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, a procedure, a function, or the like which performs the functions or operations described above. The software code can be stored in memory and driven by the processor. The memory is located inside or outside the processor and can exchange data with the processor by various means already known.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential characteristics thereof. Accordingly, the foregoing detailed description is to be considered in all respects illustrative and not restrictive. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

It will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the spirit or scope of the invention. Accordingly, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

In the present specification, the apparatus and method inventions are all referred to, and descriptions of both the apparatus and method inventions can be supplemented and applied to each other.

Various embodiments have been described in the best mode for carrying out the invention.

The present invention is used in a range of vehicle communications.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Accordingly, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

In a geo-networking transmission method of a V2X communication device,

Determining a forwarder from the neighboring V2X communication devices included in the location information, and setting an address of the determined forwarder as a link layer address;

Transmitting a geo-networking packet based on the link layer address; And

Retransmitting the geo-networking packet at specific time intervals until a maximum repetition time is reached,

Wherein the location information comprises information about at least one neighbor V2X communication device executing a geo-networking protocol,

Wherein the forwarder is determined based on a distance between the neighboring V2X communication devices included in the localization information and a destination.
The method according to claim 1,

And terminating retransmission of the geo-networking packet when receiving a conform packet from the forwarder.
3. The method of claim 2,

The conform packet may be a sender conform packet in which the forwarder confirms receipt of the geo-networking packet or a destination conform packet in which the destination V2X communication device confirms arrival of the geo-networking packet in the destination region , Geo-networking transmission method.
The method of claim 3,

Wherein the sender confirm packet comprises at least one of receive sequence number information or conform status information,

The received sequence number information has the same value as the sequence number information of the transmitted geo-networking packet,

Wherein the conform status information indicates whether the forwarder is capable of forwarding the geo-networking packet and is not possible if forwarding is not possible.
The method of claim 3,

Wherein the destination confirm packet includes at least one of sequence number information, received sequence number information, or duplication count information,

Wherein the sequence number information indicates a sequence number of the destination match packet,

The received sequence number information has the same value as the sequence number information of the transmitted geo-networking packet,

Wherein the number of times of duplication indicates the number of times the same packet reaches a destination.
6. The method of claim 5,

The destination confirm packet further includes source position vector information and destination position vector information,

Wherein the source position vector information represents a position vector of the destination V2X communication device transmitting the destination match packet,

Wherein the destination position vector information indicates a position vector of a source V2X communication apparatus that multi-hop transmits the geo-networking packet.
The method of claim 3,

Wherein the sender confirm packet corresponds to a single hop packet and the destination confirm packet corresponds to a multi-hop packet.
In the V2X communication apparatus,

A memory for storing data;

A communication unit for transmitting and receiving a radio signal including geo-networking packets; And

And a processor for controlling the memory and the communication unit,

The processor comprising:

Determining a forwarder from the neighboring V2X communication devices included in the location information, setting the address of the determined forwarder as a link layer address,

Transmits a geo-networking packet based on the link layer address,

Retransmits the geo-networking packet at specific time intervals until the maximum repetition time ends,

Wherein the location information comprises information about at least one neighbor V2X communication device executing a geo-networking protocol,

Wherein the forwarder is determined based on a distance between the neighbor V2X communication devices included in the localization information and a destination.
9. The method of claim 8,

Wherein the processor terminates retransmission of the geo-networking packet when receiving a conform packet from the forwarder.
10. The method of claim 9,

The conform packet may be a sender conform packet in which the forwarder confirms receipt of the geo-networking packet or a destination conform packet in which the destination V2X communication device confirms arrival of the geo-networking packet in the destination region , V2X communication device.
11. The method of claim 10,

Wherein the sender confirm packet comprises at least one of receive sequence number information or conform status information,

The received sequence number information has the same value as the sequence number information of the transmitted geo-networking packet,

Wherein the conform status information indicates whether the forwarder is capable of forwarding the geo-networking packet and is not possible if forwarding is not possible.
11. The method of claim 10,

Wherein the destination confirm packet includes at least one of sequence number information, received sequence number information, or duplication count information,

Wherein the sequence number information indicates a sequence number of the destination match packet,

The received sequence number information has the same value as the sequence number information of the transmitted geo-networking packet,

Wherein the number-of-duplication information indicates the number of arrivals of a destination of the same packet.
13. The method of claim 12,

The destination confirm packet further includes source position vector information and destination position vector information,

Wherein the source position vector information represents a position vector of the destination V2X communication device transmitting the destination match packet,

Wherein the destination position vector information represents a position vector of a source V2X communication apparatus that multi-hop transmits the geo-networking packet.
11. The method of claim 10,

Wherein the sender confirm packet corresponds to a single hop packet and the destination confirm packet corresponds to a multi-hop packet.