CN100514934C

CN100514934C - Communication method of mobile body

Info

Publication number: CN100514934C
Application number: CNB2005100643717A
Authority: CN
Inventors: 江端智一; 鲛岛茂稔; 小泉稔; 足达芳昭; 铃木邦弘
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2004-04-15
Filing date: 2005-04-14
Publication date: 2009-07-15
Anticipated expiration: 2025-04-14
Also published as: JP4692021B2; CN1684446A; JP2005328500A

Abstract

The invention provides an low-cost stable communication environment with respect to a moving object which is moving at a high speed. A frame is expanded and exchanged after adding information meaning the order, so that an upstream frame that cannot be transmitted is specified and transferred from a certain base station to another base station, which is present in the moving direction of a mobile host. In the other base station, a frame loss is detected and retransmission of lost frames is requested to the mobile host.

Description

The communication means of moving body

Technical field

The present invention relates to a kind of communication means that moving body with high-speed mobile is provided stable communication environment.

Background technology

In IP network, continue mobile communicator (mobile host), behind the network of change wireless zone etc., under sub-network situation about also having changed under, technology as providing continuous IP to communicate by letter has proposed mobile IP (RFC2002) mode by IETF (Internet Engineering Task Force).

With Fig. 1 mobile IP mode is carried out diagrammatic illustration.

So-called mobile IP mode, allow terminal between a plurality of wireless networks, move even be, under the situation that does not change the IP address, also can carry out the industry standard protocol of continuous IP communication, by using mobile IP, even in vehicle moves, when wireless zone moves, use the service of IP communication also not interrupt as principle.

In mobile IP mode, from mobile router (being called MR later on) in installations such as trains, receive external agent's router (being called FA later on) of the contact that has entered the wireless zone order, notify this information to home agent router (being called HA later on), HA is for FA, FA generates the tunnel (IP tunnel) that is used to transport the IP packet for MR, like this, just can be to the IP communication equipment (PC on the car in moving, server etc.) transmission of IP data bag, when the vehicle that MR has been installed enters different wireless zones, regenerate this IP tunnel, perhaps utilize the IP tunnel generated once more.

Because HA uses routing protocol to belong to the IP address of network or the main frame of MR all the time in advertisement, so mail to the network that belongs to MR or the IP packet of main frame at first arrives HA.HA uses the above-mentioned IP tunnel that has illustrated, transmits this IP packet via FA to MR.IP packet by MR emits from the tunnel is dispensed into destination network or main frames such as vehicle.

In addition, be subordinated to the network of MR or the IP packet warp that main frame sends, via MR, send to IP network on the ground, after this, the IP route by common is sent to destination host.

Problem points as mobile IP mode, can exemplify out: when mobile host is mobile between network and home agent between the formality that must put rules into practice, so, under the situation of the distance home agent logic or physics, the required time of the switching of the transmission destination of IP packet (being called handing-over later on) increases.

Therefore following problems can take place: in network when mobile before necessary step finishes, mobile host can not receive the IP frame, so can not ensure real-time continuity, the continuity of the conversation among the VoIP etc. for example.

To open the invention of being put down in writing for 2003-No. 37626 according to the spy, in order addressing the above problem, to distribute multicast address, in data send, utilize multicast frame, come the method corresponding to carry out publicity thus with this handing-over to mobile host with regard to it.So-called cast communication is to send identical data to specific a plurality of host broadcast, and so-called multicast address is the address that a plurality of main frames can common use.So-called a plurality of main frames can common use address, even be meant under the situation about moving that has produced the sub-network change of following mobile host, multicast ip address is for can commonly using between the sub-network before and after moving, so mobile host just can carry out continuous Data Receiving in moving.

In addition following problem can take place: described transition issue, particularly the speed along with mobile host becomes at a high speed, although mobile host has moved to the wireless zone that has existed, but still can produce the problem of the communication frame increase of sending to the wireless zone before moving, with since time of passing through of wireless zone become early, so described such situation can the significant problem that takes place.

For fear of this problem, according to Fast Handovers for Mobile IP (draft-ietf-mobileIPfast-mIPv6-08.txt) (below become non-patent literature 1), publicity following manner: mobile host preestablishes mobile destination-address before moving, access router by the mobile link before of oneself login, in during after mobile host moves till login at home agent, access router before moving, access router to mobile destination transmits frame, the frame loss when avoiding joining thus.

In addition, by using the spy to open 2003-No. 37626 aforesaid way, though the loss of packets in the time of can reducing mobile IP handing-over, but owing to can't avoid fully, so grind the following manner of having reported among Vol.2003, the No67 ISSN0919-6072 (below become non-patent literature 2) publicity at " in Mobile IPv6 handing-over, making the design and the installation of the mechanism that frame do not lose " academic publication principle place: by possessing a plurality of interfaces, all the time keep the communication of the wireless zone more than 2 or 2, thus, realize not taking place the mode of the mobile IP of LOF.

Yet, use the spy to open the method for the multicast of 2003-No. 37626 institutes publicity, be effectively for the application of using multicast IP, but can not in the application beyond it, use.

Especially, use with the IP agreement to use the TCP as the upper connecting-type agreement of prerequisite be the comparison difficulty.For example, in the zone that the unit repeats, might receive 2 identical IP packets, but under such situation, when the frame waste treatment of not carrying out below 2 or 2, suppose to have taken place communication abnormality and will carry out the obturation processing in TCP, service can stop.

Secondly, for relay host, the address of notice effective mobile host in the unit, by changing this log-on message, carry out method from the transmission order of relay host by publicity, but according to this method, till the change log-on message during in, to the unit of necessity dispensing IP packet, as a result of mobile host will not produce the state that can not receive the IP packet.

And then, method according to 1 publicity of non-patent literature, from behind the link that is connected to mobile destination to move the login during in, realize the high speed of handing-over, but because temporarily cut off and connect the link of mobile destination from Radio Link, still exist from the cut state of network, so the loss of IP packet takes place.

Usually,, ask to avoid communication to stop, but the problem of resource such as bandwidth of transmit frame consumption network again take place this moment by the transmission again that last bit protocols such as TCP carry out the IP frame about the loss of such IP packet.In addition, the IP packet transfer algorithm of so-called slow start is installed in TCP, in a single day this is when detecting the IP loss of packets, be considered to take place to block up at network, and make communication speed reduce to minimum speed, the communication of algorithms of the communication speed that raises gradually thereafter.In the mode of non-patent literature 1, the IP packet be lost in each switching the time take place, so can cause the reduction of communication speed when the time comes, the result in mobile IP environments, just becomes and can not communicate by letter efficiently.

And then, according to the method for 2 publicities of non-patent literature,, can avoid the IP loss of packets, but,, just the high such problem of cost price be arranged owing to need a plurality of interfaces in order to implement this mode by using a plurality of network interface unit.In addition, in communication environment,, between the effective coverage of adjacency, just produce the needs that use the different network medias or different wireless frequency, the high problem of its cost price is also arranged for a plurality of network interface unit are worked effectively.

In addition, non-patent literature 2, to by keeping the Radio Link of 2 different wireless zones simultaneously, realize that communication continuity carried out publicity, but overlapping with the wireless zone more than 2 be prerequisite, and in the environment of reality, owing to interfere the mixed letter that causes between the wireless zone or because in fact the situation of electric wave etc. can become the blind area, in such environment between wireless zone, promptly use the mode of non-patent literature 2, mobile IP guarantees that the IP communication continuity also is difficult.

This external spy opens in 2003-No. 37626, non-patent literature 1 or 2, wireless zone separately is a syntople, but in a certain wireless zone that has existed, by newly appending other wireless zone, and can not be to locating for the such example of wireless zone that in wireless zone, can not comprise other fully.

For example, be that its effective range of 2Mbps involves the long first such wireless communication unit of 20km for bandwidth, appended bandwidth and be the wide bandwidth of 100Mbps and the such other such situation of second wireless communication unit of the not enough 100m of its effective range.

And then, in above-mentioned example, when first wireless communication unit and second wireless communication unit are different wireless communication unit, must manage from which paths and transmit communication frame, when continuous in addition frame was transmitted via other communication unit, the arrival sequential control of carrying out this frame was difficult.

And then, in above-mentioned example, when first wireless communication unit and second wireless communication unit are the wireless communication unit of identical type, except above-mentioned problem, also there are the following problems: even can be identified under the situation of other infinite regions that newly append in a certain wireless zone that has existed in the mobile communicating cell side, in during before breaking away from this wireless zone to identification, the frame loss can take place.

In addition,, and replenish under the purpose of this part of leaving, when having appended new wireless communication unit, situation about having problems is arranged also even leaving at wireless zone.For example, this is because the such extraneous factor of temperature, humidity, fine day, rainy day or worsen, utilize the speed etc. of the moving body of this wireless communication unit all the year round, the reason that the effective range of wireless communication unit constantly changes.Under these circumstances, Yu Ding additional missing one's aim originally is perhaps in the interregional generation blind area of adjacency, when the situation that becomes inclusion relation as described above is also arranged.

Summary of the invention

In the present invention, the state that does not have overlapping situation as wireless zone, comprise following situation: (1) is wireless zone situation about physically leaving in fact, (2) communication in nature, when having entered new wireless zone, discard the Radio Link of old wireless zone, and make up the situation of new Radio Link, (3) because the mixed letter that causes of interference between the wireless zone or because the situation of electric wave etc. produce the situation that in fact becomes the blind area between wireless zone.

In addition, for convenience, will be called " uplink frame " to the frame that the main frame that communicates with this mobile host transmits from mobile host, the frame of Chuan Songing is called " downlink frame " round about.In addition, the base station that the radio communication that constitutes wireless zone is used is called " base station ".Provide in the present invention with lower unit: the communication frame that in first wireless zone that the main frame from move or the network of following the main frame more than 1 to move receive, acquires, the unit that second wireless zone that exists on the direction that this main frame or network move transmits; The communication frame that transmits to this second wireless zone is when this main frame or network enter this second wireless zone, to the unit that this main frame or network carry out the transmission of this communication frame.

In addition, also provide in the present invention with lower unit: to the communication frame of this second wireless zone transmission, enter under the situation of this second wireless zone at this main frame or network, when this main frame or network transmit this communication frame, rewrite the content of this communication frame so that transmit the unit of this wireless communication frame via this second wireless-communication-capable area; And then, the communication frame that has transmitted to this second wireless zone, when this main frame or network do not enter this second wireless zone, the unit of storage or discarded this communication frame.

And then, also provide in the present invention with lower unit: before packet being entered into contain the network range of this wireless network, change this communication frame length, perhaps expansion, perhaps frame is divided into more than 2 or 2, guarantee to be used to control the field of the information of this communication frame, the new frame of this control information is given in generation to this field, before sending communication frame from the network range that contains this wireless network, this information that acquisition is given to this field, the field of the information that is used to control this communication frame is given in release, and the frame length of will communicating by letter in containing the network range of this wireless network changes to the unit of the state before entering communication frame.

Specifically, also provide with lower unit: before communication frame being entered into contain the network range of this wireless network, give the sequence number of sending, the unit of discarded this communication sequence number information before sending communication frame from the network range that contains this wireless network as the order of sending communication frame.

And then in the present invention, carried out when mobile to second wireless zone from first wireless zone, by will in first wireless zone, discard the value of first communication sequence number that obtains before this communication sequence number information and in second wireless zone value of the discarded second communication sequence number that this obtains before by serial number information compare, come to determine the communication frame that carried out losing when mobile to second wireless zone from first wireless zone, specifically, being sent to this second wireless zone by the communication frame that will arrive this first wireless zone realizes.

And then in the present invention, also provide with lower unit: carrying out when mobile to second wireless zone from first wireless zone, make before communication data packet enters into the network range that first wireless zone contains this wireless network, the sequence number of the communication sequence number of giving to communication frame, the unit that continues as sequence number in the communication sequence number that communication frame is given to this communication data packet before entering into the network range that second wireless zone contains this wireless network; Before communication frame being entered into contain the network range of this wireless network, all the time guarantee in this communication frame of a fixed number, the duplicating of up-to-date communication frame, accept specific loss the notice of communication sequence number of communication frame after, send the unit of this communication frame that has lost once more.

And then in the present invention, also provide with lower unit: second wireless zone that is comprised to this first wireless zone from first wireless zone carries out when mobile, after considering information such as communication quality that second wireless zone provides, communication unit is switched to the unit of this second wireless zone; The unit that perhaps uses this first communication unit and this second communication unit to continue to communicate by letter.

And then in the present invention, also provide with lower unit: in first wireless zone and second wireless zone, when appending the 3rd wireless zone, use this first, second and the positional information of the 3rd wireless base station or the positional information and the direct of travel of moving body, decision is transmitted in the unit of the wireless zone of the communication frame that first wireless zone acquires.

According to the present invention, the uplink frame when avoiding switching simultaneously and the loss of downlink frame, and then can eliminate the frame arrival delay that when switching, takes place.Even particularly when the mobile host high-speed mobile, also can guarantee steady I P communication continuity.

In addition, can provide according to the present invention: need not a plurality of network interface unit, realize unit based on the continuous communiction of the mobile IP of 1 network interface unit.

In addition, according to the present invention, even in wireless zone, comprise the such communication environment of wireless zone or interim append under the such situation of wireless zone the mobile IP of the IP continuity of the aforementioned stable of also giving security.

Description of drawings

Fig. 1 is the synoptic diagram of the mobile IP mode of expression;

Fig. 2 is the overall diagram of the system among expression first embodiment;

Fig. 3 is the diagram of the hardware configuration of expression car upside frame control device 32;

Fig. 4 is the diagram of the hardware configuration of expression ground upside frame control device 32;

Fig. 5 is the diagram of the hardware configuration of expression car upside frame control device 32;

Fig. 6 is the diagram of the software configuration of expression ground upside frame control device 12;

Fig. 7 is the diagram of expression by the frame of ground upside frame control device 32 generations;

Fig. 8 is the figure of the communication sequence number admin table of expression overground system frame control device 12;

Fig. 9 is the synoptic diagram of the processing of expression uplink frame;

Figure 10 is the precedence diagram of summary of the processing of expression uplink frame;

Figure 11 is the synoptic diagram of the processing of expression downlink frame;

Figure 12 is the precedence diagram of summary of the processing of expression downlink frame;

Figure 13 is the synoptic diagram of system of the processing of the uplink frame of expression among second embodiment;

Figure 14 is illustrated in the diagram that comprises the system configuration of a plurality of wireless communication units in 1 FA territory;

Figure 15 is the diagram of scene of the enforcement of expression the 4th embodiment;

Figure 16 is the diagram of the system mode of expression the 4th embodiment;

Figure 17 is the key diagram of content of the various information of other ground upside frame control device of being had of ground upside frame control device;

Figure 18 is the restriction that is not subjected to the frame control of maximum MTU value, can transmit the maybe key diagram of the method for the frame more than this value of this value.

Embodiment

Below, embodiments of the present invention are described.

[embodiment 1]

In the present embodiment, to with train in network (below, be called network on the car) between the main frame that connects and base station, sub-network, underlying network and the main frame on the internet of ground upside, even this train is in the high-speed mobile, also can provide the execution mode of the communication mode of steady I P continuous communiction to describe.

At first, carry out the explanation of present embodiment before, with Fig. 1 the summary of native system as the mobile IP mode of prerequisite described.

So-called mobile IP mode even be to move in a plurality of wireless network chien shih terminals, does not change the IP address, can carry out the industrywide standard agreement of continuous IP communication yet.

In mobile IP mode, receive the external agent's router (being called FA later on) of contact that enters into the order of wireless zone from mobile router (being called MR later on), this information is got in touch with to home agent router (being called HA later on), by HA for FA, FA generates the tunnel (IP tunnel) that is used to transport the IP packet to MR, can be to IP communication equipment (PC, server etc.) the transmission of IP data bag on the car in moving, when entering the different wireless zone of MR, newly-generated or utilize this IP tunnel once more.

HA uses routing protocol to notify the network that (advertisement) belong to MR or the IP address of main frame all the time, so mail to the network that belongs to MR that disposes in the train in moving or the IP packet (downlink frame) of main frame, at first arrives HA.HA uses the IP tunnel of above-mentioned explanation, transmits this IP packet via FA to MR.With the IP packet that MR discharges from the tunnel, be deployed on the target carriage on the network, and by the main frame of dispensing to network on the car.

In addition, be subordinated to the network of MR or the IP packet that main frame sends, transmit to the network of ground upside via MR, then, the IP route by common transmits to destination host.

Fig. 2 represents the entire system figure in the present embodiment.

Train 3 possesses network 30 on the car, and network 30 connects server 35 on mobile routers (hereinafter referred to as MR) 31, the car, passenger with personal computer (following is called passenger PC) 36.In addition, network 30 can be any one networks such as wired lan, WLAN on the car.PC36 can be equipped onboard regularly in addition, also can be that the passenger brings in the train.

In MR31, polyphone connects: car upside frame control device (in addition, do " AIR-T " as being called for short note in the drawings) 32, to carry out from digital leakage coaxial cable (be digital leakage coaxial cable, abbreviate DLCX later on as) the leakage electric wave transmitting-receiving car upside transceiver (be called " car upside DLCX " transceiver later on, note is made " DLCX-T " in the drawings) 33, upside DLCX antenna 34.In addition, so-called DLCX is by be provided with small gap (slit) in the armouring of coaxial cable, make electro magnetic, only wireless sense band is guaranteed in the small field (tens of m) around DLCX, also in high tunnel, capital carry the automobile telephone relaying with, with use in professional wireless etc. in the tunnel.

In underlying network 10, be connected with external agent's router (hereinafter referred to as " FA ") 11, also be connected with: ground upside frame control device (in addition, in the drawings as being called for short, note is done " AIR-G ") 12, upside DLCX transceiver (in addition, as being called for short, note is done " DLCX-G " in the drawings) 13, DLCX14.Between the ground upside frame control device 12,, be connected with other ground upside frame control device VLAN of adjacency via VLAN switch 15 (in addition, doing " SW " as being called for short note in the drawings) and region network 20.

And then, in underlying network 10, be connected with home agent (hereinafter referred to as " HA ") 19, become professional gateway with network 40 and internet 50.Professional with server 41 in business with connecting in the network 40, in internet 50, be connected with Internet server 51.In addition, this business comprises Web service, mail service, network management services etc. with the service that server 41 or Internet server 51 provide, and is not particularly limited about the service content of server.

Fig. 3 is the hardware configuration of expression car upside frame control device 32.

By intercommunication lines (hereinafter referred to as bus) 321 such as buses, be connected with: the network interface unit 322 that is used for being connected, be used for network interface unit 323, CPU325, the memory 324 that is connected with car upside DLCX transceiver 33, the hard disk controller 327 that has connected hard disk 328 and be used for the external interface group 329 of local this device of control via the interface of display, mouse, keyboard or RS232C etc. with MR31.

Fig. 4 is the hardware configuration of expression car upside frame control device 12.

Be connected with by bus 121: the network interface unit 122 that is used for being connected, the network interface unit 123 that is used for being connected, be used for

network interface unit

124 or 125, CPU126, memory 127 that the ground upside frame control device via region network 20 and adjacency is connected, connect the hard disk controller 128 of hard disk 129 and be used for the external interface group 130 of local this device of control via the interface of display, mouse, keyboard or RS232C etc. with FA11 with ground upside DLCX transceiver 33.

Fig. 5 is the software configuration of expression car upside frame control device 32.

Preserve: the network interface unit controlling and driving program 324-2 that is used for Control Network interface card 322,323, between the MR31 of Fig. 2 or car upside DLCX transceiver 32, implement the communication management module 324-4 of communication, transmit queue 324-6, receive formation 324-4, the input and output controlling and driving program 324-8 of the data input and output that control and hard disk are 328.

Preserve: the long MTU control module 324-10 of MTU (so-called " MTU " is the abbreviation of " Max transfer Unit ", is the parameter that determines the frame sign that once can send) that is used to control MR31; The communication sequence number that uplink frame is given communication sequence number or carried out the deletion of downlink frame communication sequence number is paid removing module 324-12; Detect the loss of downlink frame and ask the downlink frame that sends the once more loss detection of this loss frame to send request module 324-14 once more; The occasion that loses when uplink frame, send the transmission processing module again 324-26 of processing again; Receive the mobile detection module 324-16 in wireless * zone that the detection wireless zone moves the information of order from car upside DLCX transceiver 33; From long-range via network entry to car upside packet control device 32 back, the remote server module 324-18 of carrying out various settings and maintenance function is provided; Be used for driver group 324-22 the external interface group 329 of this device of this accessing; Carry out the setting module 324-20 of the various settings of this device; And the temporary transient memory module 324-24 of uplink frame of preserving the processing of a certain a certain number of up-to-date uplink frame.

Fig. 6 represents the software configuration of ground upside frame control device 12.

Preserve: the network interface unit controlling and driving program 127-2 that is used for Control Network interface card 122,123,124,125; Implement the communication management module 127-4 of communication on the ground between side DLCX transceiver 13, FA11 or the region network 20; Transmit queue 127-6; Accept formation 127-4; The input and output controlling and driving program 127-8 of the data input and output of control and hard disk 129.

Preserve: the long MTU control module 127-10 of MTU that is used to control MR11; The communication sequence number that the IP packet is paid communication sequence number or carried out the deletion of uplink frame communication sequence number is paid removing module 127-12; Detect the loss of uplink frame and ask the uplink frame that sends the once more loss detection of this loss frame to send request module 127-14 once more; Diminish the transmission processing module once more 127-30 of missing the season, send once more processing in downlink frame; The wireless zone that moves the information of order from ground upside DLCX transceiver 13 reception detection wireless zones moves detection module 127-16; From long-range via network entry to car upside packet control device 12 back, the remote server module 127-18 of carrying out various settings and maintenance function is provided; Be used for from the external interface group's 329 of this device of this accessing driver group 127-22; Carry out the setting module 127-20 of the various settings of this device; For contents such as the Agent Solicitation of investigating mobile IP, agent advertisement message, monitor frame monitor module 127-24 by the IP packet of this device; Frame back, that use this information to rewrite content frame such as the MAC of the frame that obtains monitoring from above-mentioned module or IP address is rewritten module 127-26; To the ground of the wireless zone on train direct of travel upside frame control device 12 transmit frames, packet forwarding module 127-32; And the temporary transient memory module 324-24 of uplink frame of preserving the processing of a certain a certain number of up-to-date downlink frame.

Secondly, in order the action of car upside frame control device 32 is described from starting.

In addition, in the present embodiment, in order more easily to understand the content of explanation, use Ethernet (login trade mark) (containing ethernet wan) to record and narrate medium and suppose car upside frame control device 32 or ground upside frame control device 12 also uses Ethernet to record and narrate as the physical network media of communication usefulness, but the use of Ethernet in the present invention is not an essence of the present invention, if the network media of the IP network of conveyance IP packet can be provided, any network media can use.

Car upside frame control device 32, by display, mouse, keyboard or from interfaces such as RS232C, via external interface group 329, from this locality starting setting module 324-20, like this, use the setting of the IP address order that IP address, subnet mask, default gateway, broadcast address or DHCP function etc. by

network interface unit

322 or 323 dynamically provide.After setting the IP address in this wise, just can utilize network, so also just can set from long-range via remote server module 324-18.

Secondly, from long-range or local starting setting module 324-20, the MAC Address of the MR31 that input is connected with network interface unit 322 and to the value of the MTU value of the frame ethernet frame of MR31 setting.Because the MTU value is maximum 1500 (bytes) during Ethernet, so will set the value also littler than 1500 bytes (for example 1400 (bytes)).

In addition, also to set the direct of travel of train.For example, just be set at 1 if just be set at 0 if leave the direction in Tokyo towards the Tokyo direction.

In addition, when uplink frame has been lost, in order to carry out setting the frame number (for example 300,000 frames) that is used for preserving all the time some latest frames at storage area sending processing again.When surpassing a fixed number, cover up-to-date frame by zone, discarded old frame at the old frame of storage.

Ground upside frame control device 12, by display, mouse, keyboard or from interfaces such as RS232C, via external interface group 130, from this locality starting setting module 127-20, like this, use the setting of the order of the IP address that IP address, subnet mask (networkmast), default gateway, broadcast address, VLAN ID or DHCP function etc. by

network interface unit

122 or 123 or 124 or 125 dynamically provide.After setting the IP address in this wise, because the utilization of network becomes possibility, so, via remote server module 127-18, also become possibility from long-range the setting.

Secondly, from long-range or local starting setting module 127-20, the MAC Address of the FA11 that input is connected with network interface unit 123 and to the value of the MTU value of the frame ethernet frame of FA11 setting.The value that this MTU value and side frame control device 32 have onboard been set is identical.

In addition, when downlink frame has been lost,, be used for preserving all the time the frame number of some (for example 300,000 frames) latest frames with train unit, setting at storage area in order to carry out sending processing again.When surpassing a fixed number, cover latest frame by zone, discarded old frame at the old frame of storage.

Fig. 7 represents the frame by 32 generations of ground upside frame control device, in addition, omits the record of MAC with CRC (4 eight bit bytes).

From the car network 30 as uplink frame arrive MR the frame ethernet frame, the change of the set point by MT reconnaissance U value, MTU is transformed into 1400 bytes or the following upstream message 1-1 of 1400 bytes, arrives the network interface unit 322 of car upside frame control device 32 from MR31.

Upstream message 1-1 is paid removing module 324-12 in the communication sequence number that is sent to Fig. 5, by after the temporary transient transcription, after the 1400th byte on this memory, is paid up ID on the memory.

Up ID is made of direct of travel sign, train identification serial number, uplink frame communication sequence number.The direct of travel sign, revealed train direct of travel via setting module 324-20 inputs.For example, just be set at 1 if just be set at 0 if leave the train of Tokyo direction to the train of Tokyo direction.In addition, as the train identification serial number,, can be sequence number arbitrarily, but in the present embodiment, use MAC Address (12 byte) if whole train is paid unique value.MAC Address is unique value of being paid when Ethernet card is made, so otherwise the conflict of generation MAC Address.

And then, in the uplink frame communication sequence number, use integer value.Communication sequence number is reset to 0 when train operation begins, 1 frame duration of every transmission just rises 1, just is reset to 0 once more if arrive maximum.By using the communication sequence number of enough big figure place, just can omit processing to resetting.In the present embodiment, use the integer value (0～4294967295) of 4 bytes,, also can use nearly 23 hours even implement the transmission of 50,000 frames in 1 second as communication sequence number.

In addition, in above-mentioned example, only paid the up ID that amounts to 16 bytes, and in addition, in the IP data of shown in 1-3, encrypting, also to pay secret head about the control information of this encryption, HMAC etc., like this, also just side

frame control device

32 and 12 encryptions of implementing frame of ground upside frame control device onboard.

Like this, paid the frame information of up ID, become the Ethernet data bag of common MTU by transcription, as frame ethernet frame 1-2, send to car upside DLCX transceiver 33 from the network interface unit 323 of Fig. 3, via ground upside DLCX antenna 34, the DLCX14 and the ground upside DLCX transceiver 13 of upside, arrival point upside frame control device 12.

Downstream message also is sent to the communication sequence number of Fig. 6 and pays removing module 127-12, on the memory temporarily by transcription after, after the 1400th byte on this memory, paid descending ID.

As the method beyond the above-mentioned method of picture, as uplink frame, the request that MR31 proposes change MTU to passenger PC36 (for example, making MTU is 1400 request), AIR-T32 by paying the control information of 100 bytes, just can implement the processing of purpose same as described above.In addition, for downlink frame, also carry out processing like this.

In addition, the maximum MTU value of ethernet frame is 1500, but by the processing of implementing the driver of network card is transformed etc., utilization can be paid 1600 bytes or the above such character of information of 1600 bytes, as uplink frame, ethernet frame to maximum 1500 bytes of sending to AIR-T32 via MR31 from passenger PC36, after also paying the control information of 100 bytes, send to AIR-G12, by in AIR-G12, removing control information, also can implement the processing of purpose same as described above.In addition, to downlink frame, also carry out processing like this.

In addition, because the maximum MTU of ethernet frame is 1500, thus will take place cutting apart of frame for surpassing the such message of this value, but the above-mentioned method of recording and narrating, purpose is will avoid in AIR-T32 or AIR-G12, for frame by paying the generation that frame that ID causes is cut apart.

If when the generation frame is cut apart in AIR-T32 or AIR-G12, in the frame of the first half, be transmitted according to the former state of not paying control information, so, in AIR-T32 or AIR-G12, just can not implement to contain the discarded frame of communication sequence number and handle.

But, by in AIR-T32 or AIR-G12, paying ID, even surpass in the MTU value under the situation of 1500 such frames (for example 1600 frames), finally in AIR-T32 or AIR-G12, if the frame (that is, if can be assembled into 1600 byte frames) that can ressemble at transmitting time point is just no problem.This be because, beyond between AIR-T32, AIR-G12, remove ID after, as a result of the MTU value is that 1500 bytes or 1500 bytes are transmitted to get off.

At Figure 18 this method is described.

Frame (a) becomes the frame of total length 1560 by being that the frame of 1460 bytes is paid the ID of 100 bytes to total length, will produce frame and cut apart in common processing.Therefore, in AIR-T32 or AIR-G12, frame (a) is cut apart framing (b) and frame (c) consciously.

That is, 1560 bytes are divided into after the frame of the first half 1480 bytes and half 80 byte of back, in last 20 bytes of last field, the sequence number of the own frame of record expression and the sequence number of the frame that is connected with this frame.Similarly in one field of back, also put down in writing the frame number of oneself, but because the frame that is not connected with this frame, so just at this record NULL.

In this frame (b) AIR-T32 or AIR-G12 (c) that receives,, revert to the frame of original length by assembling once more.Like this, be not subjected to the restriction of the frame control of maximum MTU value, in fact, can transmit the above frame of maximum MTU value.

Fig. 8 is the communication sequence number admin table 127-50 of the common use of module group of overground system frame control device 12 shown in Figure 6.

This car of item record of direction is to the car of Tokyo direction, still leaves the car of Tokyo direction.Thus, ground upside frame control device 12 just can be judged and can transmit frame to the ground of which adjacency upside frame control device 12.

The item of train identification serial number is illustrated in the train that this moment overground system frame control device 12 carries out the frame control and management, puts down in writing the uplink frame of overground system frame control device 12 processing and the up-to-date communication sequence number of downlink frame respectively in the item of the item of uplink frame communication sequence number, downlink frame communication sequence number.

The communication sequence number of descending ID, communication sequence number by overground system frame control device 12 is paid removing module 127-12, with the interlock of advancing of train, with the train identification serial number, this module of the overground system packet control device 12 of train notified direct of travel, thus, guarantee the consistency of communication sequence number.Management control method about this downstream IP will be set forth in the back.

In addition, wireless zone moves detection module 127-16, is detecting when the train of wireless zone enters, under the situation that the train identification serial number item consistent with the train identification serial number do not have, be identified as train operation when beginning, append this, the downlink frame communication sequence number is set at 0.

The frame information of descending ID will have been paid like this, transcription is to the Ethernet data bag of common MTU, transmit to ground upside DLCX transceiver 13 by the network interface unit 122 of Fig. 4, via DLCX14, upside DLCX antenna 34, car upside DLCX transceiver 33, arrive car upside frame control device 32.

Fig. 9 or Figure 10 represent the summary of the processing of uplink frame.In Fig. 9, omit about the device of DLCX association, the record of other networks.In addition, " eth0 " among the figure, the expression of " eth1 " are network interface unit in each device of expression, Ethernet.In addition, suppose that train advances in right in figure.

By the frame ethernet frame of MR31 with 1400 transmissions of MTU value, by above-mentioned such, paying removing module 324-12 by communication sequence number pays after the communication sequence number ID, become after the frame ethernet frame of MTU value 1500, (territory, temporary storage aera also can be by memory shown in Figure 3 324 to copy to the territory, temporary storage aera by the temporary transient memory module 324-24 of uplink frame, in the hard disk 328 one generated) in after, via interface eth1, be sent to the interface eth0 of the ground upside frame control device 12-1 of wireless zone 1, former state is from interface eth3, via the VLAN of region network 20, deliver to the ground upside frame control device 12-2 of the wireless zone 2 that is positioned at the train direct of travel.

At this, uplink frame loss detection by ground upside frame control device 12-2 sends request module 127-14 once more, the up ID of the frame ethernet frame that inspection is sent here, in downlink communication sequence number admin table 127-50, corresponding uplink frame communication sequence number item, write down up-to-date communication sequence number with the train identification serial number.Under the item non-existent situation corresponding with the train identification serial number, newly-generated.After the communication sequence number record end, this frame ethernet frame is handed to communication sequence number and is paid removing module 127-12, deletes up ID, carries out sending from ethernet network interface card eth2 after the calculating again etc. of CRC, sends (step 1) via FA11-2 to underlying network.

When train 3 had entered into 2 blind areas that can not communicate by letter of wireless zone 1 and wireless zone etc. just, car upside frame control device 32 also continued to send frame, and frame around here has loss (step 2).

Entered the stage of wireless zone 2 at train 3, the overground system DLCX transceiver 13-2 of car upside DLCX transceiver 33 and wireless zone 2 is discerned the existence of train 3 respectively, and with its notice overground system frame control device 32 and ground upside frame control device 12-2, usefulness wireless zone separately moves detection module 324-16 and 127-16 and confirms.At this constantly, the request of transmission once more of the loss frame when crossing over wireless zone for horse back is that frame control device 32 and ground upside frame control device 12-2 enter holding state (step 3) on the car.

Train 3 enters after the wireless zone 2, uplink frame loss detect send once more request module 127-14 receive from car system-frame control device 32 over the ground upside frame control device 12-2 send initial frame the time, confirm train identification serial number with communication sequence number admin table 127-50 corresponding the uplink frame communication sequence number.This communication sequence number is if not successive value, owing to produced the frame loss of 2 of wireless zone 1 and wireless zones, so the uplink frame loss detects and sends request module 127-14 once more, after paying the information of the communication sequence number that has been considered to lose, on the car request of transmission once more of 324-26 notification frame of transmission processing module once more of system-frame control device 32.

Receive the transmission processing module once more 324-26 of this request, according to duplicating of the frame of being put down in writing in the territory, temporary storage aera by the temporary transient memory module 324-24 of uplink frame, find the frame corresponding with this request after, transmit to ground upside frame control device 12-2.This packet also with above-mentioned the same ground upside frame control device 12-2 from wireless zone 2, transmits (step 4) to the ground of wireless zone 3 upside frame control device 12-3.

After the above-mentioned processing or before, the opportunity that is treated to the Agent Solicitation of mobile IP, agent advertisement message etc., when having carried out the agent logs request, (step 5) transmits uplink frame to the ground of wireless zone 3 upside frame control device 12-3 also not influence above-mentioned processing.

In addition, about having passed through the train of wireless zone fully, owing to do not need the item of communication sequence number admin table 127-50, so wireless zone moves detection module 127-16, in certain hour (for example 60 seconds) lining, when in uplink frame communication sequence number item, both values of downlink frame communication sequence number item, not changing, comprise that train identification serial number item deletes.

Figure 11 or Figure 12 represent the summary of the processing of downlink frame.In this figure, omit the device related, the description of other networks with DLCX.In addition, " eth0 " among the figure, the expression of " eth1 " are the network interface unit of the Ethernet in each device of expression.In addition, suppose that train is that right in figure is advanced.

MR31 is between the FA11-1 of wireless zone 1, by the flash request message that exchanges mobile IP, urgent advertisement information, by MR31 HA19 is carried out the agent logs request, when returning the agent logs response as its response, the frame monitor module 127-24 of overground system frame control device 12-1, detect the content that this agent logs is replied, obtain the MAC Address of the network interface unit of MR31.

Secondly, the overground system frame control device 12-1 of wireless zone 1, to the temporary transient memory module 324-34 of downlink frame, carry out to the ground coefficient of wireless zone 2 according to the temporary transient memory module 127-34 of the downlink frame of packet control apparatus 12-2, be used for the generation trust of the temporary transient field of storage of record by the downlink frame of overground system packet control device 12-1 (temporary transient field of storage also can be that the one by memory 12-7 shown in Figure 4, hard disk 129 generates).

The temporary transient memory module 127-34 of downlink frame uses the MAC Address of the network interface unit of MR31 to generate temporary transient storage file.For example, the MAC Address of the MR31 of this train is if 00-50-56-C0-00-08 then also can make the such filename (step 1) of 00-50-56-C0-00-08.buf.

Then, downlink frame from FA-1 transmission, before being sent to ground upside DLCX transceiver 13-1, side frame control device 12-1 duplicates it on the ground, be sent to ground upside frame control device 12-2, and the filename of this MAC Address is stored in the territory, temporary storage aera of being paid (step 2).

When train 3 has entered the blind area of wireless zone 1 and wireless zone 2, also carry out the processing identical, but do not receive the frame (step 2) that ground upside DLCX transceiver 13-1 sends with above-mentioned steps 2.

When train 3 enters wireless zone 2, detecting separately of car upside DLCX transceiver 33 and ground upside DLCX transceiver 13-2, and with its notice wireless zone move detection module 324-14 and 127-16, wireless zone detection module 127-16, to the temporary transient memory module 127-32 of downlink frame, send indication (transmission begins indication): end storage, be sent to ground upside DLCX transceiver 13-2 same as before to the territory, temporary storage aera.Remain in this moment, the LOF when the wireless zone leap does not take place is so the benefit of the unnecessary covering that the newly arrived frame in avoidance territory, temporary storage aera produces.And at this constantly, communication sequence number is paid removing module 127-12 in order to communicate the continuous of sequence number, writes down the maximum (step 4) of the communication sequence number of the downlink frame of transmission to some extent according to step 5 described later or step 7.

Since to the blind area charge into or login process postpones, and MR31 wireless zone 1 fail to receive frame, be stored in the ground upside frame control device 12-2 of wireless zone 2, become the state that send that can send out once more.Car upside frame control device 32 receives and begins to indicate the packet that is sent at first by wireless zone 2 according to transmission, the communication sequence number of this downlink frame by inquiry, can specifically determine the frame lost, car upside frame control device 32, upside frame control device 12-2 over the ground, (step 6), ground upside frame control device 12-2 carry out the transmission once more of this frame and handle (step 7) to carry out the request of transmission once more of these lost frames.

Then, after the processing of step 8 or step 9, according to aforesaid order, the ground upside frame control device 12-2 of wireless zone 2, ground upside frame control device 12-3 to wireless zone 3 sends the request that generates the territory, temporary storage aera, simultaneously communication sequence number pay removing module 127-12 will be in this moment according to the maximum of the communication sequence number of the downlink frame that step 5 or step 7 sent, be set at the initial value that communication sequence number is paid the communication sequence number that removing module 127-12 manages.

And, after logining, wireless zone 2 is carried out definitely not having from the possibility of the transmission of the frame of wireless zone 1.Reason is that the propagation delay of backbone network 10 or region network 20 might take place.

Therefore, after the processing of Step.9,, rewrite module 127-26 according to frame about the frame that sends from 1 pair of wireless zone 2 of wireless zone, implement frame head rewriting so that this frame send over by FA11-2.Specifically, will send the address that source MAC is rewritten as the FA11-2 of wireless zone 2, will send target ip address is rewritten as the MR31 that obtains in login is replied new IP address.And the communication sequence number of descending ID is paid the sequence number that removing module 127-12 is given from the communication sequence number of ground upside frame control device 12-1, and the communication sequence number that is rewritten as ground upside frame control device 12-2 is paid the communication sequence number (step 10) of removing module 127-12 management.

About the downlink frame of carrying out after the agent logs request, the processing after above-mentioned steps 2 is identical.

Embodiment 2

In the present embodiment, in the system configuration of Fig. 2 of embodiment 1, under the situation that does not have VLAN switch 15 and region network 20, embodiments of the invention describe.

Figure 13 is the synoptic diagram of system of processing of the uplink frame of expression present embodiment.

In embodiment 1, ground upside frame forwarding apparatus to the wireless zone by frame being forwarded to the moving direction that is positioned at train 3, the mode that solves the LOF of mobile IP is illustrated, but in the system and arranging of reality, can infer, in most cases, for this frame is sent to other ground upside frame control device 12-1 and will newly prepares network from ground upside frame control device 12-1, this is very difficult on cost.Therefore, in the present embodiment, to by not using such region network, and the example that uses underlying network 10 to obtain the invention effect identical with embodiment 1 describes.

In the present embodiment, in the described frame forwarding module 127-34 of Fig. 6, the function with IP tunnel realizes.

At first, become: from long-range or local starting setting module 127-20, the eth1 separately and the eth3 of all ground upside frame control device 12 are paid in suitable IP address, can carry out mutual IP communication by underlying network.

Next, all frames that will send from the eth3 of ground upside frame control device 12-1 encapsulate as the data that the IP frame transports, and send it to the IP address of the eth1 of ground upside frame control device 12-2.Because FA11 also as common router acts, if record and narrate the IP address that sends destination address, just can arrive the network interface card of purpose IP address.Packed mistake the IP packet, the frame forwarding module 127-34 that is utilized ground upside frame control device 12-2 receives, at this, it is original frame ethernet frame as being unfolded, and carries out the processing identical with embodiment 1 afterwards.

Figure 13 only is illustrated uplink frame, by downlink frame being carried out and described identical processing, also can carry out the forwarding to the place ahead of frame wireless zone.

Embodiment 3

In the present embodiment, in the system configuration of Fig. 2 of embodiment 1, when having appended the wireless communication unit of new identical or different kind, embodiments of the invention describe.

Figure 14 has appended wireless LAN base station (in addition, being designated as " SS-G " as abbreviation among the figure) 16, the 2 ground upside DLCX transceivers (in addition, being designated as " DLCX-GS " as abbreviation among the figure) 17, wireless lan adapter 37 on the AIR-G12 of Fig. 2.

The wireless zone of SS-G16 or DLCX17 is included in the wireless zone of DLCX-G13, supposes and has carried out in advance setting so that letter does not take place to mix between these wireless zones.

The car upside DLCX transceiver 33 of train 3 carries out drive sweep or active scan, constantly search ground upside DLCX transceiver.In addition, be documented in " the 802.11Wireless Networks The Definetive Guide " of the Mattew S.Gast of O ' REILLY company work about drive sweep, active scan.

DLCX7 constantly sends and comprises the current beacon signal of utilizing the information such as total length of the wireless zone that communication bandwidth, DLCX-GS provide, when in a single day DLCX-T33 receives it, sends this signal to AIR-T32.

Whether AIR-T32 disconnects and the communicating to connect and establish once more and the judgement that communicates to connect of DLCX-GS17 of DLCX-G13, and when being judged as under the situation of not carrying out, still keeps and the communicating to connect of DLCX-G13.When being judged as under the situation of carrying out, AIR-T32 sends the message of the order of switching communication to AIR-G12, interrupts uplink frame is sent to the processing of DLCX-T33, and message that will network 30 sends from car constantly is stored in the buffer storage.

Receive the AIR-G12 of the message of the order of switching communication, also interrupt downlink frame is sent to the processing of DLCX-G13, will constantly be stored in the buffer storage from the message that FA11 or SW15 send.

Next, AIR-T32, order DLCX-T33 carries out the disconnection process that is connected with DLCX-G13, reach with being connected of DLCX-GS17 and establish processing, behind the signal of the order that the establishment that is received this connection processing by DLCX-T33 has been finished, AIR-T32 begins to carry out once more in order the transmission of frame from the frame that is stored in buffer storage.

Similarly, AIR-G12 is behind the signal of the order that the establishment that receives this connection processing from DLCX-GS17 has been finished, and also the frame from be stored in buffer storage begins to carry out once more in order the transmission of frame.

And, the car upside DLCX transceiver 33 of train 3, carry out drive sweep or active scan, detecting when having broken away from the wireless zone that DLCX-GS17 provides, be notified to AIR-T32, AIR-T32 after the order of the order that is connected of DLCX-T33 having been carried out open and DLCX-GS17, establish once more DLCX-G13 connection processing and carry out the buffer memory stores of frame and send processing according to described order.AIR-G12 also handles successively in proper order.

But, in that the stage that the wireless zone that provides from DLCX-GS17 breaks away from is provided, having become not communicable state, the possibility of the LOF that sends from DLCX-GS17 or DLCX-T32 is very big.

So, in the present embodiment, also carry out among the embodiment 1 the remedying of lost frames of the method used.That is, when uplink frame or downlink frame are lost,, in storage area, be set with the frame number (for example, 300,000 frames) of the up-to-date frame that is used to preserve some in order to handle once more.In addition, when surpassing some, become: in the zone that up-to-date frame is covered the old frame of record, abolish old frame.

In embodiment 1, by detecting the stage that has broken away from the wireless zone that DLCX-GS17 provides, also carry out the identical processing of processing carried out with the stage that enters wireless zone 2 at train 3, can realize that the transmission once more of these lost frames is handled.

DLCX-T33 omits and disconnects and the processing that communicates to connect of DLCX-G13 in the time can keeping communicating to connect more than 2 or 2 simultaneously, also can carry out above-mentioned processing.At this moment,, reduce, therefore, can expect to improve the effect of continuity the amount of message stores in buffer storage owing to can shorten the time of disconnection process that communicates to connect and the establishment that communicates to connect processing.

In addition, DLCX-T33 also exists and keeps with the communicating to connect of DLCX-G13 in the same old way, carries out the method for communicating with DLCX-GS17 concurrently in the time can keeping communicating to connect more than 2 or 2 simultaneously.In this case, because the difference of the transfer rate of the communication bandwidth of DLCX-G13 and DLCX-GS17, downlink frame may arrive AIR-T32 with opposite order.At this moment, the communication sequence number of deletion that possesses the communication sequence number of the downlink frame of utilizing the car upside frame control device 32 carry out Fig. 5 is paid removing module 324-12, with reference to communication sequence number, and the function that rearranges according to the frame ascending order, after rearranging the sequence number of frame, send it to network 30 on the car.

Under the situation of uplink frame, same reason, the communication sequence number of deletion that possesses the communication sequence number of the uplink frame of utilizing the ground upside frame control device 12 carry out Fig. 6 is paid removing module 127-12, with reference to communication sequence number, the function that rearranges according to the frame ascending order, after rearranging the order of frame, send it to FA11 or SW15.

And the car upside DLCX transceiver 33 on the train 3 carries out drive sweep or active scan, is not only continuous search ground upside DLCX transceiver, also constantly searches for wireless LAN base station.Because DLCX is different wireless communication units with WLAN originally, therefore except the disconnection that do not need to connect, establishment, once more establish etc. handle, be so that be the method for criterion with the method for above-mentioned 2 DLCX.

When DLCX-T33 kept communicating to connect more than 2 or 2 at the same time, AIR-G12 or AIR-T32 controlled so that fetch by separately communication link and to transmit different types of frame.In AIR-G12 or AIR-T32, check the port sequence number of the IP packet that receives, switch to the processing that communicates to connect that transmits frame according to its port sequence number.

For example, keep respectively when communicating to connect at DLCX-G13, DLCX-GS17 and DLCX-T33, perhaps, DLCX-G13 and DLCX-T33, SS-G16 and SS-T37 keep when communicating to connect respectively, in the communicating to connect of DLCX-GS17 and DLCX-T33 or SS-G16 and SS-T37, only transmit the frame of the packet that comprises port sequence number with specific TCP or UDP.

Thus, can carry out following processing: the packet that file transmits (FTP) usefulness transmits discontinuously, and network management transmits all the time with the packet of (SNMP etc.).

Embodiment 4

In the present embodiment, following embodiment is described: be not only the such such vehicle of train of only advancing of the foregoing description to a certain direction, also go for not limiting the such vehicle of automobile of direct of travel, and, of the same race or different types of wireless communication unit, with different by the situation of the embodiment 3 of terminal by ground upside frame control device, under the situation of having appended new wireless communication unit interimly, becoming in order whether to determine between the wireless zone for comprising, overlapping, discrete when waiting such system configuration of state, or owing to reasons such as weather, the occasion of described state fluctuation also can provide the stable communication environment shown in the foregoing description 1 to 3.

Figure 15 has represented the form of the system of present embodiment, but in order to conclusively show content, omitted to the description of the next base station, wireless base station that is connected of HA, AIR-G, this HA, AIR-G are connected with the upper of FA1, FA2, FA3.In addition, in the inside of vehicle 4, suppose the system that has constituted based on network on the wireless lan adapter, AIR-T, MR and the car that are had by vehicle shown in Figure 14 3.

In addition, in the present embodiment, as wireless communication unit, being illustrated with WLAN, but also can being DLCX or other wireless communication unit, also can be that they mix existence.

In the last figure of Figure 15, represented in the zone between wireless zone 1 and wireless zone 2, according to FA3, AIR-G3 and wireless LAN base station base station, in system, newly appended the appearance of wireless zone 3.The direction of vehicle 4 for from wireless zone 1 under the situation that wireless zone 2 is advanced, the forwarding of the place ahead wireless zone of the frame that this forward direction is carried out to AIR-G2 from AIR-G1 changes to from AIR-G1 to AIR-G3, carries out frame from AIR-G3 to AIR-G2 and transmits.

But in figure below of Figure 15, according to above-mentioned various conditions, when rare wireless zone 3 having taken place be comprised in situation in the wireless zone 1, vehicle 4 enters wireless zone 1 after entering according to the order of wireless zone 1, wireless zone 3 once more.Under this situation,, can produce the problem that to implement by the moving body continuous communiction of embodiments of the invention 1 to 3 realization owing to can not carry out the forwarding of wireless zone forwards.In order to address this problem, also need the forwarding to AIR-1 from AIR-3.

Figure 16 is the diagram of having appended the situation of wireless zone 5 in the system that represents to be made of wireless zone 1 to 4.At first, as the external interface group of AIR-G5, by GPS receiver 1301 or control picture etc., when obtaining positional information according to manually operated input via Fig. 4, use IP broadcast by FA5, underlying network 10 and each FA, will comprise AIR-G5 positional information message be sent to each AIR-G.Next, each AIR-G, with reference to the source IP address of IP broadcast with oneself positional information be returned to AIR-G5.So, all AIR-G obtain position and the IP address of other AIR-G by exchanging the positional information of oneself mutually, grasp the relation of adjacent wireless zone between each wireless zone by each AIR-G.

Figure 17 represents that the information conversion of peripheral AIR-G that AIR-G5 is had is the diagram that cartographic information shows.In addition, AIR-G5 necessarily needs cartographic information.In addition, identification title, IP address, the latitude longitude information of AIR-G are represented in the record of " AIR-G5: ' 192.168.21.35 ' ' 139.31.29.257/35.35.00.592 ' " respectively.AIR-G5 can grasp adjacent wireless zone from other AIR-G positional information.

In embodiment 1 to 3, carry out the forwarding of frame at the wireless zone of the direct of travel of vehicle, and in the present embodiment, be the forwarding of carrying out frame at adjacent wireless zone.

The frame that the wireless zone that does not enter to vehicle 4 is transmitted is not used, goes out of use through behind the official hour.

Transmit by carrying out such frame, also go for the such object of the uncertain automobile of direct of travel.In addition, shown in figure below of Figure 15, even certain wireless zone becomes the such situation of wireless zone that is comprised in other, owing to do not need to consider in the non-conterminous interregional relation that comprises that becomes at least, therefore even after vehicle 4 enters according to the order of wireless zone 1, wireless zone 3, enter once more under the situation of infinite region 1,, can keep the continuous communiction mode by carrying out the forwarding of frame to wireless zone 1 from wireless zone 3.

But, adjacent so whole AIR-G are carried out the forwarding of frame, can force the bandwidth of invalid use underlying network 10, and consume ample resources among the AIR-G for frame is stored in.

Therefore, like that only when a direction is advanced, as long as it is just enough to carry out the forwarding of frame to direct of travel and the direction into of driving in the wrong direction, and when even supposition is automobile, the occasion that resembles direction the highway and be a direction also is same at mobile body image train.When road diverged, only the direction to its fork transmitted just enough.

In addition shown in the circle of the dotted line of Figure 17, also can only carry out the place ahead and transmit from the position of AIR-G of oneself to the AIR-G that is positioned at certain certain distance.

In moving body being provided all systems of continuous communication environment, can use.

Other advantage and improvement are conspicuous for those skilled in the art that.Therefore, the present invention is shown in it is not limited to here aspect wider and the specific details of explanation and represent embodiment.Therefore, can carry out various modifications and not break away from scope by the general inventive concept of claims and equivalent thereof definition.

Claims

1. the communication means of a moving body, be moving body with car upside frame control device from the communication means of the moving body of first wireless zone when second wireless zone with second ground upside frame control device moves with first ground upside frame control device, it is characterized in that

This communication means comprises the steps: when handling uplink frame

The described first ground upside frame control device of described first wireless zone, receive the expanding communication frame of having paid as the communication sequence number of the order of sending communication frame from described moving body, and described expanding communication frame sent to the described second ground upside frame control device of second wireless zone, the described second ground upside frame control device is temporarily stored the described expanding communication frame of reception

The described second ground upside frame control device receives the expanding communication frame of having paid as the communication sequence number of the order of sending communication frame from the described car upside frame control device of the described moving body that arrives this second wireless zone, therefrom extract as the communication sequence number of sending the order of communication frame, communication sequence number and the communication sequence number as the order of sending communication frame from the expanding communication frame that the described first ground upside frame control device receives as the order of sending communication frame that extract are compared, when comparative result was not successive value, the described second ground upside frame control device sent the communication frame that has lost once more to the car upside frame control device of described moving body;

This communication means comprises the steps: when handling downlink frame

The described first ground upside frame control device of described first wireless zone, the expanding communication frame of paying as the communication sequence number of the order of sending communication frame is sent to described moving body, and described expanding communication frame sent to the described second ground upside frame control device of second wireless zone

The described second ground upside frame control device sends the expanding communication frame of having paid as the communication sequence number of the order of sending communication frame to the described car upside frame control device of the described moving body that arrives this second wireless zone, the described car upside frame control device of described moving body extracts as the communication sequence number of sending the order of communication frame from the expanding communication frame that the described second ground upside frame control device sends, and the communication sequence number of order of communication frame is sent in the conduct that will extract and the communication sequence number that the order of communication frame is sent in the conduct in the expanding communication frame that the described first ground upside frame control device sends compares, when comparative result was not successive value, described moving body sent the communication frame that has lost once more to the described second ground upside frame control device request.

2. the communication means of moving body according to claim 1, it is characterized in that, when handling downlink frame, in second wireless zone, the described car upside frame control device of described moving body, receive described expanding communication frame, obtain conduct and send the communication sequence number of the order of communication frame, and dwindle this communication frame.

3. the communication means of moving body according to claim 1 is characterized in that,

When handling downlink frame, the described car upside frame control device of described moving body, will be in first wireless zone compare the communication frame of having determined to lose to the order of the order of the communication frame that second wireless zone is sent and the communication frame that in second wireless zone, receives from first wireless zone.

4. the communication means of moving body according to claim 1 is characterized in that,

When handling downlink frame, in second wireless zone, the described car upside frame control device of described moving body receives described expanding communication frame, obtains to keep this communication frame as the communication sequence number of sending the order of communication frame.

5. the communication means of moving body according to claim 3 is characterized in that,

When handling downlink frame, determined the moving body of the described communication frame that has lost, request sends the described communication frame that has lost again, receives duplicating of the communication frame sent to second wireless zone from first wireless zone.

6. the communication means of moving body according to claim 1, wherein,

The length of expanding communication frame is in the MTU value.

7. the communication means of moving body according to claim 1 is characterized in that,

The ground upside of described moving body or car upside frame control device make it produce frame and cut apart having paid expanding communication frame as the communication sequence number of the order of sending communication frame before first or second wireless zone is sent.

8. the communication means of moving body according to claim 1 is characterized in that,

Second wireless zone is all wireless zones with the first wireless zone adjacency.