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    • 专利摘要:
    A wireless communication system and method for a moving vehicle having a plurality of carriages, such as trains, is disclosed. The system comprises a plurality of routers, each router being arranged in a separate carriage and each router being configured to receive and transmit wireless data communication to and from a stationary communication server outside said moving vehicle through at least one exterior mobile network via at least one antenna, wherein said at least one exterior mobile network provides at least one data link; receive and transmit data packets to and from at least one client onboard the moving vehicle; and communicate with every other router in said moving vehicle in order to receive and transmit data packets to and from said every other router, thereby forming an onboard router network. At least one controller is provided and configured to evaluate a set of performance parameters of said at least one data link between each router and said at least one exterior mobile network in order to assign data streams to said at least one data link, through said onboard router network, at least partly based on said evaluated set of performance parameters.For publication: Fig. 1
    公开号:SE1651060A1
    申请号:SE1651060
    申请日:2016-07-14
    公开日:2018-01-15
    发明作者:Karlsson Mats；Eklund Peter
    申请人:Icomera Ab；
    IPC主号:
    专利说明:

    DISTRIBUTED WIRELESS COMMUNICATION SYSTEM FOR MOVINGVEHICLES TECHNICAL FIELD OF THE INVENTION The present invention relates to a wireless communication system for moving vehicles, such as trains.
    BACKGROUND The demands on wireless communication capabilities in today's societyare increasing rapidly. ln particular, there is an increasing demand frompassengers to be able to communicate through mobile phones and otherhandheld devices when traveling. Furthermore, there is also a rapidly growingdemand to be able to get access to the Internet with laptops, PDAs,smartphones, and the like when traveling, for example, by train. However,train carriages are made of metal, and even the windows are normallycovered with a thin metal film. Thus, train carriages are often shieldedcompartments, and direct communication between terminal antennas withinthe carriages and externally located antennas is difficult to obtain. Further, inregards to recent developments in the field of smartphones, and the waythese are commonly used, with e.g. continuously operating applications,many smartphones are active at all times, meaning that many handovers arerequired when the train moves. Even though this problem is common for allmoving vehicles, it is especially pronounced for vehicles moving at highspeed, such as trains.
    The mobile nature of a client with respect to the base stations may alsointroduce several potential sources of communication performancedegradation. Such sources may derive from complex terrain, competition foravailable channels, or the source may be an unknown source of noise relatedto e.g. radio-frequency interference.
    To this end, moving vehicles, such as train carriages, are oftenprovided with an external antenna connected to a repeater unit within thecarriage, which in turn is connected to an internal antenna. Hence, the communication between the passengers' terminals (e.g. handheld devices)and the operator antennas outside the vehicle occurs through the repeaterunit. Similarly, it is known to provide a mobile access router for datacommunication, also connected both to an external antenna and an internalantenna, in each carriage, in order to provide Internet access on board thevehicle. Such mobile access router solutions are e.g. commercially availablefrom the applicant of the present application, lcomera AB, of Gothenburg,Sweden, and are also disclosed in EP 1 175 757 by the same applicant. Thismethod has greatly improved the reliability of high-bandwidth wirelesscommunication for trains and other large vehicles. However, this solution maystill be insufficient to obtain an optimal transmission performance, especiallyfor large data volumes. Trains and other moving vehicles often pass throughareas with bad radio coverage, and moreover, present solutions are oftenunable to properly handle the large amount of traffic.
    Further, in the light of recent developments regarding wirelesscommunication methods and systems, such as e.g. developments relating toMIMO (multiple-input multiple-output) technology, presently known wirelesscommunication systems for trains are becoming more and more out-dated.Thus, current systems are unable to make efficient use and benefit of thedevelopments made in new telecom techniques, such as MIMO, and areoften even incapable of integrating such techniques at all.
    Yet further, MIMO systems aside, the practical limitations caused bythe limited amount of space on the roof of a train carriage is forming a bottle-neck for the bandwidth capacity for the onboard communication system.
    There is therefore a need for an improved train communication systemwhich provides better capacity and more efficient utilization of external mobilenetworks. Even though the above discussion is focused on trains, similarsituations and problems are at least to some extent encountered in othertypes of moving multi-carriage vehicles, such as trams.
    SUMMARY OF THE INVENTIONlt is therefore an object of the present invention to provide a wireless communication system and a method for wireless communication for moving vehicles, and in particular trains, which alleviates all or at least some of theabove-discussed drawbacks of the presently known systems.
    Another object of the invention is to provide a wireless communicationsystem for moving vehicles which is dynamic and robust against onboardnetwork configurations with undersized or oversized network capacity.
    These objects are achieved by means of a wireless communicationsystem for a moving vehicle as defined in the appended claims. The termexemplary is in the following to be interpreted as; serving as an example,instance, or illustration.
    According to a first aspect of the present invention, there is provided awireless communication system for a moving vehicle, such as a train, havinga plurality of carriages, said wireless communication system comprising: a plurality of routers, each router being arranged in a separate carriageand each router being configured to: receive and transmit wireless data communication to and from astationary communication server outside the moving vehicle through atleast one exterior mobile network via at least one antenna, wherein theat least one exterior mobile network provides at least one data link; receive and transmit data packets to and from at least one clientonboard the moving vehicle; communicate with every other router in the moving vehicle inorder to receive and transmit data packets to and from every otherrouter, thereby forming an onboard router network; at least one controller configured to evaluate a set of performanceparameters of the at least one data link between each router and the at leastone exterior mobile network in order to assign data streams to the at leastone data link, through the onboard router network, at least partly based on theevaluated set of performance parameters.
    Such a system improves the traveling experience for customers and ismore compatible with current technological trends than presently knownwireless communication system for moving vehicles. Moreover the system iseffectively provided with means to distribute data traffic within the onboard router network in an optimal way improving the overall performance of thesystem.
    Each “router” (or sometimes “mobile router”) is a networking router,which is a machine that forwards data packets between computer networks,on at least one data link. The routers may be mobile access routers, andpreferably a mobile access and applications routers. ln accordance with one exemplary embodiment, the wirelesscommunication system comprises one controller for each router and whereineach controller is configured to: evaluate a set of performance parameters of the at least one data linkbetween the router and the at least one exterior mobile network, in order toassign data streams to the at least one data link, through the onboard routernetvvork, at least partly based on the evaluated set of performanceparameters. The controller can be provided by means of appropriatesoftware, hardware or a combination thereof. ln this exemplary embodiment,each controller is in operative connection with one individual router and isable to communicate with other controllers onboard the moving vehiclethrough the router network. The controller may be partly or wholly integratedinto the router or a standalone unit connected to the router. Optionally, thesystem may comprise only one single central controller in operativeconnection with each individual router on board the vehicle.
    A set of internal LANs may be provided inside the moving vehicle forproviding (wireless) communication between each individual router and atleast one client (sometimes referred to as terminal) onboard. ln oneexemplary embodiment, each internal LAN may provide WiFi communicationbetween one router of the plurality of routers and at least one client onboardthe moving vehicle. ln other words, each carriage is preferably onlyassociated with one internal LAN provided by one router, however, theinventive system allows each client to have indirect access to the otherrouters via the onboard router network. Moreover, the at least one clientonboard may accordingly be connected to one of the plurality of routers via aLAN (local area network) provided by one or more wireless access pointswithin the public transport vehicle. Preferably, at least one such wireless access point is provided in each carriage. Each wireless access point is to beconnected to a specific router of the p|ura|ity of routers, such that a p|ura|ity ofc|ients (or terminals) onboard the moving vehicle are effectiveiy distributedamong the p|ura|ity of routers by dependence on the location of each clientwithin the moving vehicle.
    The p|ura|ity of routers may be spread out and arranged in specificcarriages of the moving vehicle, such as e.g. in a front passenger carriage, aback passenger carriage and/or a cafe carriage. However, each carriage inthe moving vehicle may also be provided with a separate router connected toat least one wireless access point in the same carriage, where the wirelessaccess point may be external to the router or an integrated function of therouter.
    “Data streams” are traffic in need of routing. A stream is in the contextof the present application to be seen as any and all communication with aspecific combination of ultimate source and ultimate destination IP addressesand network ports, or whatever the equivalent of this would be in a networkingscheme where these identifiers are not used or not sufficiently distinguishing.A stream is “created” when any entity on one side of the system seeks tocommunicate with any entity on the other side, using any specific combinationof ports.
    Each stationary communication server may be any server or siteaccessible through the exterior mobile network, such as a DNS server, an ISPinfrastructure gateway, an aggregation gateway, a content provider server ofinterest to vehicle passengers, or the like. For all common applications of thisinvention, the stationary servers will constitute the lnternet, but partly orpurely private network applications are also feasible.
    Each router and the remote server (stationary communication server)are preferably connected through a p|ura|ity of exterior mobile networks,which are simultaneously useable. Also, each router is preferably arranged tocommunicate with the stationary communication server on at least twodifferent data links (communication routes) having different characteristics,i.e. performance parameters, where the performance parameters can bemeasured and evaluated by the controller. This may be used to evaluate and links provided by a single router, and to distribute data streams betweenthese links, but may also be used to evaluate links provided by two or morerouters, each router providing only one or a limited number of links, and thendistributing the data streams between these links accessible through differentrouters.
    The different routers are furthermore preferably arranged tocommunicate on different data links, i.e. each router is preferably arranged tocommunicate on at least one different data link as compared to the otherrouters onboard the moving vehicle. The performance parameters mayinclude at least one of: packet loss (intermittent failure for packets of data toarrive), latency (round-trip response time, hence responsiveness),throughput/bandwidth (overall rate of data transmission, whether current orpotential) and a variety of radiophysical metrics, such as signal strength. Thedata streams are then fon/varded on one or several links to and from adedicated external server, which may be referred to as an aggregation serveror gateway. The different links can thereby form a single virtual link between arouter and the gateway.
    The evaluation of a data link is can for example be performed by themethods as described in EP 2 943 011 by the same applicant, said documenthereby incorporated by reference. Furthermore, the plurality of routers mayuse any available data links, such as two or more of e.g. GSM, Satellite, DVB-T, HSPA, EDGE, 1X RTT, EVDO, LTE, WiFi (802.11) and WiMAX; andcombine them into one virtual network connection. ln particular, it is preferredto use data links provided through wireless wide-area network (WWAN)communication technologies. ln light of the technological developments during the last decade thepresent inventors realized that conventional communication systems formoving vehicles will not be able to handle the increased amount of data trafficwithout significant changes.
    As discussed in the background section, MIMO-systems are notparticularly compatible with current systems using only one single router in acentrally positioned carriage. Moreover, it is not very practical to distribute theantennas on different carriages, e.g. two or four antennas on each carriage, since the signal wire (e.g. coaxial cable) connecting each antenna to thesingle router (or the modem(s) within the router) will need to be very longwhich would severely degrade the performance of the communication systemdue to high losses. Moreover, distributing antennas along the plurality ofcarriages would also be problematic due to the fact that one would need tohandle tedious connections between carriages and furthermore the carriageconfigurations would be rather complicated.
    The invention is based on the realization that in order to increase theMIMO capabilities of an onboard communication system one should aim tomaximize the separation between the antennas. For example, a 2x2 MIMOsystem, where two antennas have the same polarization, should have theantennas maximally separated from each other in order to improvecommunication performance. Generally, the onboard mobile access router isnowadays provided with 6 or more modems, and with each modem beingconnected to two or more antennas, the number of antennas that need to bemounted on the exterior of the carriage quickly exceeds practical limitations,especially if one is to maximize the separation between each antenna pair onthe roof of the carriage. As mentioned, the two antennas should preferably bemaximally separated, and furthermore, no other antennas should be placed inbetween these two in order to optimize performance. However, by means ofthe present invention, the antennas may be maximally separated, sinceantennas for different links may be arranged on different carriages. Thus, arouter providing only one link may have MIMO-antennas distributed at theedges and/or corners of the carriage, providing maximum separation.
    Thus, the inventors realized that by having a distributed communicationsystem, i.e. a plurality of routers positioned in different separate carriagesinstead of one single centrally positioned router, many advantageous effectscan be achieved. The distributed routers are completely standalone andindependent, thus there is no main or master router, but rather “peer routers”.Moreover, by configuring the routers to be able to communicate with eachother through an onboard router network data streams can efficiently bedistributed among the plurality of routers and the corresponding exteriornetwork connections. Thus, each router can “borrow” bandwidth capacity from any one of the other routers onboard the vehicle. This results in a superiorcommunication system in terms of capacity and bandwidth capability.Moreover, the communication system is more robust as compared toconventional systems. For example, if one router would temporarily not beable to communicate with an exterior mobile network due to e.g.softvvare/hardware malfunction, poor network coverage, signal obstruction,etc., the data packets received from and sent to clients can instead be routedto other routers onboard the vehicle. Also, since each router is standaloneand independent the communication system is less dependent on one singlerouter. ln accordance with another exemplary embodiment, each routercomprises a plurality of modems for communication with the at least oneexterior mobile network, wherein each modem is connectable to at least twoexternal antennas in order to enable MIMO communication. Thus, the routermay comprise several antenna ports per modem, enabling MIMO for theexternal communication, and the high bandwidth thereby provided can thenbe distributed to the internal clients with e.g. 802.1 1 n. The modemscomprised by each router may share a plurality of antennas, i.e. there may befor example two or four antennas arranged on the roof of a carriage whichcan only be utilized by one modem at the time. Alternatively a carriage havinga router may have two or more antenna configurations, each antennaconfiguration including a plurality of antennas distributed on the exterior of thecarriage, and where each configuration is simultaneously usable by two ormore modems.
    For example, a carriage may have two antennas at a front end portionand two antennas at a rear end portion of the roof which can either define oneside of one 4x4 MIMO system or one side of two 2x2 MIMO systems. Where,one side of a MIMO system is to be understood as that the moving vehiclebeing “a side” and a base station of an exterior mobile network is “the otherside”.
    According to yet another exemplary embodiment the wirelesscommunication system further comprises a distributed database including atleast one of available bandwidth of each data link of each router, a current mobile network operator of each router, a set of signal parameters for eachdata link of each router, a network topology of the onboard router network, anumber of routers in the onboard router network and an IP-address of eachrouter in the onboard router network. By providing a database in the systemcomprising certain parameters that are accessible by each router or eachcontroller a simple and efficient distributed communication system can berealized. The distributed database can be a plurality of databases, e.g. onefor each router connected to the onboard router network. The distributeddatabase(s) can then be kept continuously synchronized between thedifferent routers connected to the onboard router network in order to ensurethat each router has access to the same information at all times. Thedistributed database may further include the network topology of the routersonboard the vehicle, i.e. how they are connected to each other and if forexample packets from a first router must pass through a second router inorder to reach a third router, or if there is a direct communication path fromthe first to the third router, and so on. The controller(s) may then, inaccordance with another exemplary embodiment, also be configured toretrieve information from the distributed database and assign data streams atleast partly based on the retrieved information.
    Further, in accordance with yet another exemplary embodiment, eachrouter of the plurality of routers is associated with a different mobile networkoperator. Thus, if a specific network operator has poor network coverage incertain areas, other routers within the same moving vehicle having othernetwork operators with better network coverage can be used to handle someof the data traffic.
    Moreover, each router may further comprise a subscriber identitymodule (SIM) pool including a plurality of SIMs, and wherein the controller iscapable of periodically assigning SIMs within the SIM pool to any one of theplurality of routers through the onboard router network. By including a SIMpooling capability in the system the number SIM cards (SlMs) and also thenumber of modems in the system can be reduced. By using a common poolof SlMs, accessible to each of the plurality of routers, the total number ofSIMs may be reduced, and the SIMs available may be used more efficiently.
    At the same time, the accessibility for each router (or the modems within eachrouter) to an adequate SIM at each time increases since the number ofaccessible SlMs can hereby be managed more efficiently.
    The term “periodically” is here used to indicate an assignment which isnot fixed, but which is established temporarily, for a certain period of time.These periodical assignments are preferably established in an optimized way,based on one or several optimization rules handled by the controller, as isdiscussed in more detail in the following.
    Furthermore, the need for stocking up each router with a large numberof SlMs, where a number of those may be identical in several of the routersonboard, is diminished. Thus, since there is no need for having a largenumber of SlMs in each router, the number of modems in each router may bereduced. Moreover, the number of modems can further be reduced sincethere is a smaller number of modems required to establish adequatecommunication quality, since it now becomes possible to use each modemmore efficiently.
    In particular, it hereby becomes possible to provide access for eachrouter to one or several suitable SlM(s) in every country in which the vehiclemay travel.
    Further, due to the pooling of all available SlMs in the system, theprobability that each router is provided with a working connection to anexterior mobile network at all times increases. ln other words, the probabilityof a scenario where one of the routers would have no SIM that is currentlyassociated with an operator having network coverage in a particular area isreduced.
    Pooling of SIM cards is per se known from EP 2 518 977 by the sameapplicant, said document hereby being incorporated by reference.
    In the above-discussed SIM pool embodiment, the SIM cards formingthe SIM pool may be arranged in one of the mobile routers, and beingaccessible for modems from all the mobile routers. Alternatively, the SlMs ofthe SIM pool may be distributed, and arranged in smaller parts in several orall the mobile routers. As yet another alternative, the SIM pool may bearranged at another unit on-board the vehicle. Thus, in any of these 11 alternatives, instead of having the SIM cards hardwired to each modem, theSIM card traffic is routed via a software serial multiplexer in each router'soperating system. The software serial multiplexer can route the SIM cardtraffic between an arbitrary SIM card in the router, or on other routers or units,and an arbitrary modem in the router. This allows any modem to use any SIMcard.
    The alternative where SIMs are pooled between routers on the vehiclemay be referred to as remote SIM with on-board SIM pool. Since SIM cardtraffic intermediately exists as data in the operating system, and since theSIM card communication protocol is fairly resistant to latency, the SIM cardtraffic can be transferred over more or less arbitrary communication links.One example of such a communication network is the ethernet backbone of avehicle. It is therefore possible to allow a modem in one router onboard avehicle to use a SIM card that is physically located inside another router, orother device, onboard the same vehicle. If the connectivity to the vehicle issupplied by a distributed set of routers, all routers in the set can share acommon pool of SIM cards that can be assigned in an arbitrary way.
    It is also possible to arrange the SIM pool on a specific unit onboardthe vehicle, such as in one of the routers or on a separate unit. Still further,the SIM pool may be arranged outside the vehicle.Such an embodiment maybe referred to as remote SIM with central SIM pool. It has been found that inaddition to the previous case, and with wwan links with low enough Iatency, itis also possible to send the SIM card traffic over the internet. It is thereforepossible to have a router with a plurality of modems and only one or a fewSIM cards physically located inside the router. These SIM cards canpreferably be of a type that can roam to any other operator's network, even ifthis implies higher data cost. This, or these, physical SIM card(s) is only usedfor the initial communication with a central SIM card bank, to get the first SIMcard identity. Once at least one other modem is connected using a remoteSIM identity, further communication with the central SIM card bank can bedone over this established link.
    As an example, the connection method for a system with four modems,1-4, an abstract tunnel T that aggregates all the modems, one SIM card 12 physically located in the router, X, and four SIM cards physically located in acentral SIM card bank, A-D, can look like this:o Modem 1 connects to the mobile network with SIM card X.o Tunnel T is established over modem 1.o Modem 2 connects to the mobile network with SIM card B, withthe traffic going over tunnel T.o Tunnel T is extended with modem 2.o Modem 1 is removed from tunnel T. o Modem 1 disconnects from the mobile network with SIM card X. o Modem 1 connects to the mobile network with SIM card A, withthe traffic going over tunnel T. o Tunnel T is extended with modem 1. o Modem 3 connects to the mobile network with SIM card C, withthe traffic going over tunnel T. o Tunnel T is extended with modem 3. o Modem 4 connects to the mobile network with SIM card D, withthe traffic going over tunnel T. o Tunnel T is extended with modem 4.
    As long as at least one modem is up, the tunnel remains up and all modems can communicate with their SIM cards in the central SIM card bank. lf all modems disconnects simultaneously, the algorithm restarts from thebeginning.
    The SIM cards for pooling in any of the above-discussed ways neednot be physical SIM cards, arranged locally or centrally, but software SlMs,also referred to as E-SIM, soft SIM or virtual SIM, may also be used. E-SlMNirtual SIM is a method where the SIM identity is electronicallytransferred from a central service to a SIM-circuit or a smart-SIM-card insidethe router. This smart SIM/SIM-circuit can hold multiple SlMs identities at thesame time. Normally you can only use one SIM identity at the same time, soeach modem needs one smart SIM-card or SIM-circuit per modem. So whenthe SIM-identity is downloaded to the router, they can be used withoutcommunication with the central service/server. 13 lf you have four modems and four smart-SIM/SIM-circuits and eachSIM circuit/smart modem have five SIM-identities, then it's possible to travelthrough five countries and shift subscription at each border and have all fourmodems connected at all time without communicating with the centralserver/service. ln this case twenty subscriptions are used.
    Using this technology it is also possible to change SIM-identity/subscription without changing physical SIM-cards. This method hasthe advantages of the SIM-multiplexer and the Remote SIM without theirweaknesses of having the administration of physical SIM-cards.
    Sharing/pooling of the SIM-cards between carriages, and possiblyeven between vehicles, provides many advantages. For example, the amountof data being forvvarded through various modems and SIMS may vary greatly,both over time, and between different carriages and vehicles. Many SIMshave a cap on the available monthly data amount, and if you pass that cap,the communication through the SIM will restricted/throttled, so thattransmission will occur at very limited data speed on that SIM/subscriptionduring the rest of the month. On the other hand, if the available data for eachSIMs/subscriptions are not used for a certain month, it can often not be savedfor later, which means that you pay for resources that you do not use. Bydistributing and sharing the SIM capacity, the available amount of data trafficcan be distributed and used more efficiently. Hereby, it becomes possible touse fewer SIMs without any reduction in performance, or to obtain animproved performance.
    Further, SIM pooling makes the change of subscription plans etc easier tohandle, especially when the SIM cards are arranged externally rom thevehicle, or even are non-existent (E-SIM /virtual SIM). Many subscriptionsare locked to a physical SIM, changing subscription plan or operator mayrequire that you are changing the physical SIMs in the onboard router.Shipping SIM-cards out to customers is tedious and expensive, and thensomeone needs to open the router and fit physical SIM-cards inside therouter. This takes time, needs planning and logistics. lf something goes wrongyou may need to send back and change one or several SIMs. This is veryresource demanding activities. ln the case you want to change or add a new 14 Cellular operator to the router, you need to change and fit new physical SlMsinside the router. This is much easier to handle if you have all SlMs arrangedcentrally in a separate location outside the vehicle (remote SIM with externalSIM pool), or have the SlMs in virtual firm.
    Further, as already indicated, the use of a central SIM pool, be it withphysical or virtual SlMs, also enabling pooling between vehicles, and not onlybetween carriages within a single vehicle. Hereby, the distribution and use ofSlMs can be administered and handled even more efficiently. For example,this may be used for handling all SlMs for entire fleets of busses, trains or thelike. Hereby, the utilization of data capacity for each SIM can be optimized.For example, SlMs for a vehicle having low data traffic can periodically beexchanged with SlMs from a vehicle having high data traffic, SlMs forvehicles being periodically out of traffic may be removed and use elsewhere,SlMs having reached the cap limit for the present month may be taken out ofuse and replaced with other SlMs until the end of the month, etc. These andother features and advantages of the present invention will in the following befurther clarified with reference to the embodiments described hereinafter.
    BRIEF DESCRIPTION OF THE DRAWINGSFor exemplifying purposes, the invention will be described in closer detail in the following with reference to embodiments thereof illustrated in theattached drawings, wherein: Fig. 1 is a schematic illustration of a train having a wirelesscommunication system in accordance with an embodiment of the presentinvention; Fig. 2 is a schematic flow chart illustrating an operating sequence of arouter in accordance with an embodiment of the invention.
    DETAILED DESCRIPTIONln the following detailed description, preferred embodiments of the present invention will be described. However, it is to be understood thatfeatures of the different embodiments are exchangeable between theembodiments and may be combined in different ways, unless anything else is specifically indicated. Even though in the following description, numerousspecific details are set forth to provide a more thorough understanding of thepresent invention, it will be apparent to one skilled in the art that the presentinvention may be practiced without these specific details. ln other instances,well known constructions or functions are not described in detail, so as not toobscure the present invention. ln the following examples, an embodimentrelated to a train is disclosed. However, it is to be acknowledged by the skilledreader that the method and system are correspondingly useable on othermoving vehicles having a plurality of carriages, such as trams and the like.
    Fig. 1 shows a schematic illustration of a vehicle 1, in the form of atrain 1, having a plurality of carriages 2, three of which are shown in thisfigure. The train 1 has a communication system comprising a plurality of datacommunication routers 3, or simply routers 3, arranged in separate carriages2 of the vehicle 1. ln this particular illustration each carriage 2 is providedwith a router 3, however, in other embodiments of the invention only somespecific carriages 2 may be provided with a router 3, such as e.g. a frontpassenger carriage, a rear passenger carriage and a café or restaurantcarriage. The data communication routers 3 may also be denominated MAR(Mobile Access Router) or MAAR (Mobile Access and Applications Router).
    Each router 3 is configured to receive and transmit wireless datacommunication to and from a stationary communication server through atleast one exterior mobile network 4, e.g. external wide area networks(WANs), as indicated by the dashed arrows. Communication to and from theexterior mobile networks 4 is provided via one or several antennas 5. Theexterior mobile network 4 accordingly provides one data link or several datalinks between each router 3 and the stationary communication server. ln thecase where two or more data links are available they can either be betweenthe router 3 and one of the exterior mobile networks 4 and/or by using severalexterior mobile networks 4 simultaneously.
    Moreover, the routers 3 are configured to receive and transmit datapackets to and from one or more clients 6 onboard the vehicle 1 through aninternal local area network (LAN) 7. The LAN 7 is preferably a wirelessnetwork, using one or several internal antennas to communicate with clients 6 16 or terminal units 6 within the vehicle 1. The c|ient(s) may be computingdevices such as laptops, mobile telephones, PDAs and so on. lt is alsopossible to use a wired network within the vehicle 1. Each router 3 ispreferably connected to or part of a separate and different LAN 7 ascompared to the other routers 3 within the vehicle 1, for example, if eachcarriage 2 is provided with one router 3 then each carriage 2 is provided witha separate LAN 7.
    The routers 3 are furthermore connected to each other through anonboard router network 10 in order to receive and transmit data packets toand from each other. This enables each router 3 within the wirelesscommunication system of the vehicle 1 to “assist” each other by distributingdata traffic from the c|ient(s) 6 onboard the vehicle 1 among each other.
    The communication system further comprises one or severalcontrollers 9, in this illustration each router 3 is provided with an individualcontroller 9 that is configured to evaluate a set of performance parameters ofthe data link(s) between each router 3 and the exterior mobile network(s) 4.The controllers are then to assign data streams to the different data linksthrough the onboard router network 10 at least partly based on this evaluationof the performance parameters. lt is also possible to use only one singlecontroller in operable connection with each of the routers 3 onboard themoving vehicle.
    The plurality of routers 3 are arranged to communicate on severaldifferent communication routes having different characteristics, in someembodiments each router 3 is configured to communicate on at least twodifferent communication routes having different characteristics. However, thesystem allows for the different routers 3 within the train to have separate anddifferent communication routes to and from the exterior mobile network 4, e.g.owned by different network operators. The various data streams can betransferred and distributed among the plurality of routers on the different datalinks, based on e.g. available bandwidth, such that clients 6 onboard the train1, are always sure to receive the best data connection available.
    The transferring of data streams through different data links mayadditionally or alternatively comprises the two main steps: evaluation and 17 assignment. Each of these permits some variability. Numerous types of tests,generating a predictable response, such as an echo, could be performed toevaluate link quality, and such tests can be combined in any order, serially orin parallel. The following are only examples.
    Any of a variety of common lnternet functions can be taken to indicatethe usefulness of a link. For example, a WWAN lnternet service provider(ISP) will normally offer the addresses of one or more domain name system(DNS) servers, an essential service. DNS queries can be bound to each link,to attempt to resolve a largely arbitrary domain name using one of the lSP'sprovided servers, or any other. Failure to respond within a given time frame istaken to mean either a general problem transferring the small amount of data,or a more specific problem with the queried DNS server. lf the queried DNS server belongs to the ISP, the latter will oftenindicate a severe problem at the ISP for that specific link. Because a DNSrequest typically consists of a single UDP or TCP packet going each way, thistype of test is very light. The infrastructure typically prioritize DNS queries andDNS responses highly in traffic control algorithms, which is another reasonwhy this type of test can be expected to complete very quickly, if at all. Thetimeout on it can therefore be set very low, producing high responsiveness.The lightness of a DNS test is both an advantage and, to some extent, adrawback. lt detects qualitative problems, and is very quick. lt also results in alow transfer of data, and does not strain the link, which in turn means that thetests can be repeated very frequently. However, because it does not strainthe link, it is a poor indicator of quantitative performance.
    Another example of an embodiment therefore uses the ICMP protocol.ln this protocol, an ECHO_REQUEST datagram is used to elicit anECHO_RESPONSE from an arbitrary remote host, preferably a very stableone. ln normal use, ICMP testing is light in the same way as DNS testing. lnaddition, it is easier for lSPs to prioritize ICMP in unknown ways, because it isa special protocol and does not represent an essential service. UnpaddedICMP requests are likely to receive a very high priority, because ICMP is astandard test of network latency. When highly prioritized, it gives the illusion 18 of good overall responsiveness, while payload data in other types ofcontainers gets a lower priority and relatively poor performance in case ofcongestion.
    As part of the protocol, ICMP packets can be padded with extra bytesof data. This provides a simple, universally recognized method of loadingdown a link with a very precise burst of traffic, and timing the response. Thefact that one and the same packet constitutes the load and is timed is thegreatest virtue of this test, because it measures how heavy traffic on a link willactually be treated. ln practice, there is often a substantial difference in how astream of ICMP packets is treated, depending on their size. When paddedpackets fail to arrive under a given timeout, this is an indicator of performanceproblems.
    The ICMP request may be sent to any type of stationarycommunication server accessible through the exterior network, such as aDNS server, a gateway through which the communication from the movingvehicle is transferred, a content provider server, or the like.
    These embodiments for evaluation mentioned thus far can begeneralized as one: any active sending of a request or other provocationacross a network, through a specific link, with the expectation of receiving aresponse under a timeout or corresponding safeguard. Variations on thistheme include factors such as protocol, target host location, the amount oftraffic sent and solicited, and the precise limit set by the timeout function.Obviously, factors external to the individual test, such as the interval betweenrepetitions of the same type of test, is also a potential subject of fine tuning.These and other methods for evaluation are known from EP 2 943 011 by thesame applicant, said document hereby incorporated by reference. ln addition or as an alternative, the evaluation can also be made on thepay-load, i.e. the transmitted data streams, by identification and evaluation ofresponse times, etc.
    The system may also comprise a global positioning system (GPS)receiver 13 for receiving GPS signals indicative of the current position of thevehicle, and wherein the controller may be arranged to assign data streams tovarious data links also partly in dependence on said received GPS signals. 19 Furthermore, the router comprises a plurality of SlMs 12 a-d. Thenumber of SlMs is in this particular illustration 4, but preferably at least two,such as e.g. six, ten or twelve. The SlMs 12 form a common SIM pool 11,accessible for each of the modems 8 a-N within each router, and also to eachdifferent router 3 connected to the onboard router network 10 within thevehicle 1. The SlMs 12 are preferably SIM cards, and the SIM pool 11 isrealized as a SIM card holder, comprising a plurality of slots for receiving aplurality of SIM cards. Periodical assignment of one or several of the SlM(s)to any modem is controlled by the controller(s) 9.
    The assignment of SlMs to modems at every specific time is preferablydetermined based on a set of rules in the controller. The set of rules may e.g.be used to assign SlMs to the modems based on information such as inwhich country the vehicle is currently travelling, the amount of data that hasbeen conveyed by use of the different SlMs, the current price related toconveying data through the different SlMs, the type of data being conveyed,etc.
    The controller 9 is preferably arranged to assign each SIM within saidSIM pool only to one router (or one modem within one router) at a time.Hereby, each SIM at any given time only has one user, but the assigned usermay vary over time.
    The pooling of SIM cards within a single router is per se known fromEP 2 518 977, by the same applicant, said document hereby incorporated byreference. However, it was found surprisingly beneficial to pool a set of SlMs12 in each router 3 and make each SIM pool 11 available to each routerthrough the onboard router network 10, to further improve systemperformance.
    Fig. 2 shows a schematic flow chart illustrating an operating sequencein accordance with an embodiment of the invention. When a router in thecommunication system is powered on and has performed a first bootingsequence, it is configured to detect 201 other routers connected to theonboard router network. This can for example be done by scanning the routernetwork on certain predefined IP address ranges that are intended to be usedby the plurality of routers onboard, such as e.g. 10.101 .0.0/24. This can for example be performed by broadcasting ARP (Address Resolution Protocol)probe packets. Once, the router has determined which other routers areconnected to the onboard router network, it selects 202 an available IP-address and proceeds to a subsequent step. The other already operativerouters in the onboard router network may accordingly note that a new routerhas joined the onboard router network and its IP-address.
    Next, a distributed database 204 is formed 203a-b by one or severalcontrollers in the system. The distributed database 204 contains informationabout each router in the network, more specifically the database 204 may forexample contain information about: estimated available bandwidth of eachdata link of each router, a current mobile network operator of each router, aset of signal parameters for each data link of each router, amount of data thatis handled by each specific modem in each router, a network topology of saidonboard router network, a number of routers in said onboard router networkand an IP-address of each router in said onboard router network, (the listbeing non-exhaustive). The distributed database 204 is then updated orsynchronized by the routers so that each router has access to real-timeinformation about all routers in the communication system. The updating andsynchronization can be performed at predefined discrete time intervals orcontinuously.
    The distributed database 204 can either be formed 203a as onecommon database accessible by each router (or the controller in each router)in the onboard router network or formed 203b as several databases, one foreach router in the onboard router network, each of which is accessible byeach router. lf several databases are used they are kept synchronized so thateach router can access the same information as other routers in the onboardrouter network, the synchronization can for example be done by using opensource software such as SymmetricDS.
    Further each router provides a communication path between clientsconnected to the same internal LAN as the router and an exterior mobilenetwork. The data packets from the client(s) that are connected to the sameLAN can be routed through “local” modems and/or modems of other routers in 21 the onboard router network. This is preferably done in accordance with theSureWANTN' protocol developed by the present applicant.
    The sharing of modems between the plurality of routers in the train canfor example be performed by estabiishing a plurality of tunnels between eachrouter, or by forming different Virtual LANs (VLANs).
    Continuingly, the sequence includes a step of evaluating 205 the datalinks available in the communication system and accordingly assigning 206data streams based on this evaluation. The evaluation 205 preferablyincludes retrieving relevant information from the distributed database, e.g.checking for available bandwidth provided by other routers in the onboardrouter network.
    权利要求:
    Claims (15)
    [1] 1. A wireless communication system for a moving vehicle having aplurality of carriages, said wireless communication system comprising:a plurality of routers, each router being arranged in a separate carriageand each router being configured to:receive and transmit wireless data communication to and from astationary communication server outside said moving vehicle throughat least one exterior mobile network via at least one antenna, whereinsaid at least one exterior mobile network provides at least one datalink;receive and transmit data packets to and from at least one clientonboard the moving vehicle;communicate with every other router in said moving vehicle inorder to receive and transmit data packets to and from said every otherrouter, thereby forming an onboard router network;at least one controller configured to evaluate a set of performanceparameters of said at least one data link between each router and said atleast one exterior mobile network in order to assign data streams to said atleast one data link, through said onboard router network, at least partly basedon said evaluated set of performance parameters.
    [2] 2. The wireless communication system according to claim 1,wherein each router comprises a plurality of modems for communication withsaid at least one exterior mobile network, wherein each modem is in operativeconnection with each router of the plurality of routers through said onboardrouter network.
    [3] 3. The wireless communication system according to claim 1 or 2,wherein each router comprises a at least one modem for communication withsaid at least one exterior mobile network, wherein said modem is connectableto at least two external antennas in order to enable MIMO (multiple inputmultiple output) communication. 23
    [4] 4. The wireless communication system according to claim 3,wherein the at least two external antennas are arranged close to the fore andaft end of the carrier, respectively.
    [5] 5. The wireless communication system according to any one of thepreceding claims, wherein each router comprises a plurality of modems forcommunication with said at least one exterior mobile network, wherein eachmodem is connectable to at least two external antennas in order to enableMIMO (multiple input multiple output) communication.
    [6] 6. The wireless communication system according to any one of thepreceding claims, further comprising a distributed database including at leastone of available bandwidth of each data link of each router, a current mobilenetwork operator of each router, a set of signal parameters for each data linkof each router, a network topology of said onboard router network, a numberof routers in said onboard router network and an IP-address of each router in said onboard router network.
    [7] 7. The wireless communication system according to claim 6,wherein said controller is configured to retrieve information from saiddistributed database and assign data streams at least partly based on saidretrieved information.
    [8] 8. The wireless communication system according to claim 6 or 7,wherein said at least one controller is configured to continuously update saiddistributed database.
    [9] 9. The wireless communication system according to any one ofclaims 6-8, wherein said wireless communication system comprises onecontroller for each router and wherein each controller is configured to: evaluate a set of performance parameters of said at least one data linkbetween the router and said at least one exterior mobile network, in order to 24 assign data streams to said at least one data link, through said onboardrouter network, at least partly based on said evaluated set of performanceparameters.
    [10] 10. preceding claims, wherein said moving vehicle only comprises a router in a The wireless communication system according to any one of the front passenger carriage and a router in an end passenger carriage.
    [11] 11. The wireless communication system according to any one of thepreceding claims, wherein said moving vehicle only comprises a router in afront passenger carriage, a router in a café carriage and a router in a backpassenger carriage.
    [12] 12.preceding claims, wherein each router is associated with a different mobile The wireless communication system according to any one of the network operator.
    [13] 13.preceding claims, wherein each router further comprises a subscriber identity The wireless communication system according to any one of the module (SIM) pool including a plurality of SIMs, and wherein said controller iscapable of periodically assigning SIMs within said SIM pool to any one of saidplurality of routers through said onboard router network.
    [14] 14.preceding claims, wherein at least one router further has access to at least The wireless communication system according to any one of the one SIM in another router, and wherein the SIMs of the routers preferablyform a common, distributed SIM pool.
    [15] 15.preceding claims, wherein at least one router further has access to at least The wireless communication system according to any one of the one SIM arranged externally from the vehicle, and wherein the external SIMspreferably form a common central SIM pool accessible for more than one router within the vehicle, and/or for more than one vehicle.
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    同族专利:
    公开号 | 公开日
    CA2972647A1|2018-01-14|
    SE542226C2|2020-03-17|
    US20180020334A1|2018-01-18|
    DK3280164T3|2020-06-08|
    EP3280164B1|2020-04-08|
    EP3280164A2|2018-02-07|
    PT3280164T|2020-06-23|
    LT3280164T|2020-09-10|
    US10924901B2|2021-02-16|
    EP3280164A3|2018-04-11|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1651060A|SE542226C2|2016-07-14|2016-07-14|Distributed wireless communication system for moving vehicles|SE1651060A| SE542226C2|2016-07-14|2016-07-14|Distributed wireless communication system for moving vehicles|
    LTEP17177903.6T| LT3280164T|2016-07-14|2017-06-26|Distributed wireless communication system for moving vehicles|
    EP17177903.6A| EP3280164B1|2016-07-14|2017-06-26|Distributed wireless communication system for moving vehicles|
    DK17177903.6T| DK3280164T3|2016-07-14|2017-06-26|DISTRIBUTED WIRELESS MOVING VEHICLE SYSTEM|
    PT171779036T| PT3280164T|2016-07-14|2017-06-26|Distributed wireless communication system for moving vehicles|
    CA2972647A| CA2972647A1|2016-07-14|2017-07-06|Distributed wireless communication system for moving vehicles|
    US15/644,722| US10924901B2|2016-07-14|2017-07-07|Distributed wireless communication system for moving vehicles|
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