CN103024853B - Multimode access gateway and access method applicable to TD-LTE (Time Division-Long Term Evolution) broadband communication system of high speed railway - Google Patents

Abstract

The invention relates to a multimode access gateway and an access method applicable to a TD-LTE (Time Division-Long Term Evolution) broadband communication system of high speed railway. The multimode access gateway comprises a protocol forward module, a routing forward module, a network address translation module and a start initialization module. The invention aims to the feature that high speed railway trains support the access of various communication technology systems, the TD-LTE broadband communication system of the high speed railway can assess to 2G/3G and Internet heterogeneous networks, and the problem of data routing forwarding between the TD-LTE system and the heterogeneous networks is solved, so that the transmission rate of the whole broadband communication system is improved, and the correct transmission of service data is ensured.

Description

A kind of multimodality gateway and cut-in method being applicable to high-speed railway TD-LTE wide-band communication system

Technical field

The present invention relates to a kind of the multimodality gateway and the cut-in method that are applicable to high-speed railway TD-LTE wide-band communication system, belong to the communications field.

Background technology

Along with the development that China Express Railway is built, bullet train becomes the important vehicles that passenger goes on a journey at a distance, and meanwhile, passenger is day by day urgent to the demand of carrying out high-quality communication and digital entertainment service on bullet train.External by satellite technology, GPRS(GPRS at present) and UMTS(universal mobile telecommunications system) technology combines with WiFi wireless network, and the cross-border train of speed per hour up to 300km/h provides unbroken wireless broadband internet to connect; And have people to propose to replace the existing train operation control system based on GSM-R network based on the Train Detection and Identification network of WiMAX technology, while signal control data transmission bandwidth, provide diversified network service.And domestic passenger converses on bullet train and surf the Net mainly based on existing 2G, 3G public mobile network network.Compared with conventional wireless network overlay environment, under high-speed railway environment, because Train motion speed is fast and car body loss is large, cause wireless signal Doppler effect obvious, network switches frequent, easily there is phenomenons such as cannot connecting, frequent call drop, speech are interrupted in the terminal use on bullet train, has had a strong impact on communication quality and the service experience of passenger.Simultaneously along with the development of high-speed railway, the significantly raising of train speed, traffic safety sexual demand also can be monitored the situation in the running status of train and compartment on the ground in real time in the urgent need to strong means.In order to provide reliable and stable broadband communication services between car ground, the high-speed railway wide-band communication system based on TD-LTE is arisen at the historic moment.In this system, railway car adopts TD-LTE communication system to the communication connection of ground network; There is in compartment the feature that the multiple communication technology is accessible, namely in compartment, support multiple communication technology standard, comprise 2G/3G mobile communication technology and Internet wireless (WiFi), access in radio, the business of corresponding generation is the basic service of 2G/3G network, WiFi business of networking and railway system's video monitoring service respectively.The working method concentrating access is adopted in compartment, namely user terminal is linked into vehicle-carrying communication network by the network coverage (comprising the micro-base station of 2G/3G, Wi-Fi hotspot, video surveillance point) in compartment, when needs communicate with ground network, vehicle-mounted convergence unit is by Data Collection and be responsible for the miscellaneous service data of user terminal being sent to ground TD-LTE wireless access network by car-mounted terminal and being transferred to TD-LTE core net, finally business datum is distributed to the network corresponding to different business by the gateway device in core net.

Under this application scenarios, traditional TD-LTE core network gateway equipment (comprising Mobility Management Entity MME, gateway SGW, packet gateway PDN-GW) can not meet the demand that in high-speed railway wide-band communication system, heterogeneous network data processing forwards, thus can not ensure the fast transport of data.Need to design a kind of multimodality gateway, realize interconnecting between TD-LTE network and multiple heterogeneous network.

Summary of the invention

The technology of the present invention is dealt with problems: overcome the deficiencies in the prior art, a kind of the multimodality gateway and the cut-in method that are applicable to high-speed railway TD-LTE wide-band communication system are provided, achieve the convergence of high-speed railway wide-band communication system and heterogeneous-network service data, the functions such as identification and routing forwarding, solve TD-LTE network and between the problem that interconnects of multiple heterogeneous network, ensure that high-speed railway TD-LTE wide-band communication system supports the business that multiple communication technology standard accesses in compartment, and improve the transmission rate of whole wide-band communication system, ensure the correct transmission of business datum.

The technology of the present invention solution: a kind of multimodality gateway being applicable to high-speed railway TD-LTE wide-band communication system comprises:

Protocol conversion module, receives the data input that Routing Forward Module transmission comes, provides unified data format, be convenient to addressing and forwarding at up or down direction for Routing Forward Module; At the service connection that 2G/3G and Internet many kinds of heterogeneous networks are produced under the scene of high-speed railway TD-LTE wide-band communication system, first the QoS demand of heterogeneous-network service is mapped to QoS grades different in TD-LTE network by the mark according to class of business, again downlink data is packaged into the form of TD-LTE frame, obtain packaged business datum, pass to Routing Forward Module; When the user terminal on train by high-speed railway TD-LTE wide-band communication system be linked into ground heterogeneous network communicate with peer-entities time, according to the mark of upstream data service, from the information of TD-LTE form, isolate 2G/3G, WiFi and video monitoring service data, pass to Routing Forward Module; Described downlink data refers to that heterogeneous-network service is connected to the business datum that high-speed railway TD-LTE wide-band communication system sends user terminal in compartment to; Described upstream data refers to that in compartment, user terminal is linked into through high-speed railway TD-LTE wide-band communication system the business datum that ground heterogeneous network sends peer entity to;

In addition, this gateway device can further include: Routing Forward Module, receive the IP address after the conversion of network address conversion module input, when carrying out downlink data forwarding, business datum packaged for protocol conversion module is mapped to and has in the TD-LTE carrying of different Q CI, and provide routing function to the user terminal in compartment; When carrying out upstream data forwarding, by 2G/3G, the WiFi after protocol conversion module conversion and video monitoring service data, be forwarded to corresponding heterogeneous network.

In addition, this gateway device can further include: network address conversion module, receive the IP address that initialization module produces, for when Routing Forward Module carries out upstream data forwarding, carrying out network address translation by distinguishing before the business obtained is forwarded to corresponding user to distinguishing the business obtained; And for when forwarding module down forwards, before distributing the TD-LTE Business Stream mapped, anti-network address translation is carried out to the Business Stream of configuration; IP address after conversion passes to Routing Forward Module.

In addition, this gateway device can further include: initialization module, when gateway device accesses in TD-LTE network, by DHCP agreement, obtains the IP address distributed from PDN-GW, produces and be connected with the acquiescence of TD-LTE network; Carry out initialization connection at network side simultaneously, be connected respectively to the on-site 2G/3G Access Network of IAD, WiFi server and video equipment.In this module, the distribution of IP address is the initial procedure that all the other modules normally work, and IP address passes to network address conversion module as input.

Above-mentioned network side refers to heterogeneous network 2G/3G network, WiFi network, Internet.

Utilize the above-mentioned cut-in method being applicable to the multimodality gateway of high-speed railway TD-LTE wide-band communication system, performing step is as follows;

(1) multimodality gateway enters TD-LTE network, sets up initial service flow with TD-LTE core network element PDN-GW, and by DHCP agreement, from the IP pond that TD-LTE network is pre-set, obtains an IP address;

(2) multimodality gateway carries out initialization connection at network side, produces acquiescence respectively and is connected to the on-site 2G/3G Access Network of IAD, WiFi server, video equipment;

(3) access point of compartment user in In-vehicle networking, vehicular control unit, LTE system, multimodality gateway apply for IP address in the ground heterogeneous network belonging to user, multimodality gateway carries out DHCP RELAY and DHCP relay, be connected to the Dynamic Host Configuration Protocol server in the heterogeneous network of ground, obtain the IP address of compartment user, also referred to as far-end IP address;

(4) after compartment user obtains IP address, forwarded to the identification of the transparent transmission of the mapping of QCI, LTE system, multimodality gateway by the access of In-vehicle networking, the type of service of vehicular control unit, carry out business data transmission with corresponding ground heterogeneous network;

(5) for multimodality gateway, the flow process of upstream data and downlink data is different: to upstream data, according to the mark of upstream data service, from the information of TD-LTE form, isolate 2G/3G, WiFi and video monitoring service data and be forwarded to corresponding ground heterogeneous network; To downlink data, the QoS demand of heterogeneous-network service is mapped to QoS grades different in TD-LTE network by the mark according to agreement, again downlink data being packaged into TD-LTE packet and being mapped to has in the TD-LTE carrying of different Q CI, and routing forwarding is to compartment user.

Described upstream data process flow steps is as follows:

(11) multimodality gateway receives the data from TD-LTE carrying;

(12) resolve the packet header of business data packet, the IP head of LTE core network packet and GTP head part are peeled off, extracts QCI parameter and object IP address; Before business datum is carried in TD-LTE carrying, vehicular control unit is mapped as QCI type of service, and the object IP address marking data is ground heterogeneous network equipment;

(13) according to QCI parameter, the QCI mapping table of control design, judges type of service, according to IP address and mark thereof, thus judges the heterogeneous network belonging to business;

(14) for different heterogeneous networks, packet is formed the Frame of corresponding form at the link layer of protocol stack, and by Data dissemination to 2G/3G network, WiFi network, video equipment.

Described downlink data process flow steps is as follows:

(21) multimodality gateway receives the business datum from 2G/3G network, WiFi network, video equipment, is referred to as heterogeneous network data;

(22) the QCI information of heterogeneous network packet is extracted, identification services type, and according to the QCI mapping table designed by the QCI parameter of heterogeneous-network service Type mapping to TD-LTE network;

(23) heterogeneous network packet is added to the IP head of TD-LTE core network tunnels agreement GTP packet header and carrying, and in IP head, add the QCI parameter mapped;

(24) packaged TD-LTE network packet is mapped to TD-LTE carrying, carries out routing forwarding.

The present invention's advantage is compared with prior art: by technique scheme of the present invention, high-speed railway TD-LTE wide-band communication system can be realized to the access of multiple heterogeneous network, comprise 2G/3G network, WiFi network, Internet, the data routing forwarding problem of effective solution TD-LTE system and heterogeneous network, thus ensure that high-speed railway TD-LTE wide-band communication system supports the business that multiple communication technology standard accesses in compartment, and improve the transmission rate of whole wide-band communication system, ensure the correct transmission of business datum.

Accompanying drawing explanation

Fig. 1 be the present invention be applicable to the multimodality gateway of high-speed railway TD-LTE wide-band communication system be suitable for networking signal;

Fig. 2 is multimodality gateway architecture figure in the present invention;

Fig. 3 is multimodality gateway protocol stack in the present invention;

Fig. 4 be in the present invention multimodality gateway for the packet transition diagram of LTE network and heterogeneous network;

Fig. 5 is that in the present invention, multimodality gateway is applicable to vehicle-mounted user is linked into heterogeneous network flow chart by high-speed railway TD-LTE wide-band communication system;

Fig. 6 is multimodality gateway uplink data-mapping process chart of the present invention;

Fig. 7 is multimodality gateway downlink data distribution processor flow chart of the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments, multimodality gateway provided by the invention is described in detail.Accompanying drawing described herein is used to provide a further understanding of the present invention, and form a application's part, schematic description and description of the present invention, for explaining the present invention, does not form inappropriate limitation of the present invention.

Consider the problem of high-speed railway wideband communications service to different isomerization network data compatibility, the present invention proposes the multimodality gateway being applicable to high-speed railway TD-LTE wide-band communication system, meet user in compartment, no matter use which kind of network (2G/3G or Wifi, Internet), effective transfer of data can be carried out, make full use of Internet resources, guarantee service quality.

Table 1 hereafter lists the definition of some terms and the abbreviation adopted in the present invention.

Table 1

As shown in Figure 1, the networking schematic diagram that multimodality gateway of the present invention is used.

In the communications network, user is the passenger on compartment, and corresponding user terminal comprises 2G mobile terminal (2G MS), 3G mobile terminal (3G UE), WiFi terminal, video monitoring equipment.The wireless access system deploying In-vehicle networking corresponding in compartment, comprise the micro-base station unit of vehicle-mounted 2G (2GBTS), the micro-base station unit of 3G (3GNodeB), WiFi access point (WiFiAP), the user terminal of different systems is connected to vehicle-carrying communication by corresponding radio reception device, and Network Video Surveillance equipment is accessed by wired mode.Vehicle-mounted convergence unit is responsible for the miscellaneous service data of collection user terminal generation and is transferred to car-mounted terminal.Car-mounted terminal, as the terminal (UE) of LTE system, directly communicates with ground base station EnodeB, is responsible for the Large Volume Data wireless transfer channel building car-ground.LTE core network (EPC) comprises mobile management device MME, gateway S-GW, packet data network gateway P-GW, and its function is as 3GPP prescribed by standard, and the EPS carrying realizing LTE system is set up.Multimodality gateway connects the equipment of the core network of LTE system, and surveys at network and be connected with the access controller (3G RNC) of the base station controller (2GBSC) of 2G wireless access network, 3G wireless access network, WiFi server and video equipment respectively.2G BSC is connected to the core net (2G CN) of 2G, and 3G RNC is connected to the core net (3G CN) of 3G.Eventually through the forwarding of these heterogeneous networks of ground, set up with peer-entities and communicate.

Different from traditional LTE wide-band communication system core network gateway, multimodality gateway of the present invention is for the deployment of In-vehicle networking on bullet train, and the business datum accessed user's different wireless communication technology standard identifies, routing forwarding; The downlink service data of heterogeneous network can also be converged in LTE carrying, thus realize vehicle-mounted user and communicate with the peer-entities in ground network.

According to embodiments of the invention, provide a kind of multimodality gateway being applicable to high-speed railway TD-LTE wide-band communication system, as shown in Figure 2, comprise protocol conversion module, Routing Forward Module, network address conversion module, startup initialization module.

Particularly, protocol conversion module, the service connection produced at 2G/3G and Internet many kinds of heterogeneous networks is under the scene of high-speed railway TD-LTE wide-band communication system, first the QoS demand of heterogeneous-network service is mapped to QoS grades different in TD-LTE network by the mark according to agreement, then downlink data is packaged into the form of TD-LTE packet; On the other hand, when the user terminal on train by high-speed railway TD-LTE wide-band communication system be linked into ground heterogeneous network communicate with peer-entities time, according to the mark of upstream data service, from the information of TD-LTE form, isolate 2G/3G, WiFi and video monitoring service data.

Described downlink data refers to that heterogeneous-network service is connected to the business datum that high-speed railway TD-LTE wide-band communication system sends user terminal in compartment to; Upstream data refers to that in compartment, user terminal is linked into through high-speed railway TD-LTE wide-band communication system the business datum that ground heterogeneous network sends peer entity to.

Particularly, first to realize LTE system to map to the QoS of ground heterogeneous network.GPRS defines 5 qos parameters, priority (3 grades), time delay (4 grades), reliability (5 grades), peak throughput (9 grades) and average throughput respectively, the value that each parameter is provided with multiple rank is available, the combination of each parameter different stage value forms different QoS Profile, thus supports the multiple business of different QoS demand.Front 5 bytes of the qos parameter in 3G packet domain remain the qos parameter content in 2G, add other parameters of 8 bytes in addition, comprise type of service, transmission sequence, uplink and downlink Maximum Bit Rate, propagation delay time, the uplink and downlink Maximum Bit Rate etc. of Business Processing priority and guarantee.In LTE system, qos parameter comprises QCI (QoS Level Identifier), ARP (distribute with keep priority), the assurable bit rate of GBR(), MBR (maximum bit rate) and AMBR (Aggregate Maximum Bit Rate).Wherein, QCI and AMBR two parameters are that LTE system newly increases, and all the other parameters are then all along being used for existing UMTS system.QCI is that LTE carries one of most important qos parameter, and it is a quantitative levels, and representing LTE system should for certain SDF(business data flow) the QoS characteristic that provides, each business data flow is only associated with a QCI.Table 2 gives the standard QCI attribute of LTE system definition, and all QCI attributes all can be pre-configured to be on eNodeB by operator according to the actual requirements.

Table 2

In conjunction with the business demand of 3GPP standard and high-speed railway, the QCI attribute of the present invention's design is as shown in table 3 below:

Table 3

Particularly, in protocol data conversion, the protocol stack of multimodality gateway as shown in Figure 3, multimodality gateway is in the side be connected with LTE core network, and L1, L2 layer is as physical layer and data link layer, IP layer adopts connectionless udp protocol, on UDP, have employed GTP tunnel agreement, carrying be GTP-U data packetizing protocol, effectively can meet the transmission of LTE core network to data.Far-end IP layer realizes the transfer of data of outside heterogeneous network and compartment user terminal.Multimodality gateway, at the opposite side be connected with outside heterogeneous network, adopts simple IP agreement, L1, L2 layer only remains far-end IP layer and application layer.It is to be noted, multimodality gateway has multiple Network Side Interface, be connected with the 2G of outside heterogeneous network, 3G network, WiFi server, video equipment respectively, so different Network Side Interface is at L1, consultation on L2 layer is different, respectively with the L1 of 2G, 3G, WiFi, Internet network standard, L2 layer protocol is suitable.When data carry out protocol conversion, also the qos parameter mapped must be taken into account.

In 2G/3G business, there is the speech business in CS territory, for this part business, not yet improving in the LTE being equipped with IMS system, mainly this part of speech business being return back in 2G/3G network, namely adopting CS FallBack(circuit domain service falling) and the mono-network insertion voice business continuity of SRVCC() technology, MME supports EPS and the internetwork business intercommunication of traditional 2G/3G, comprise CS FallBack and SRVCC, concrete methods of realizing depends on operator, is not described further herein.The emphasis distinguishing isomeric data is exactly distinguish different data services, and the Floor layer Technology of data service is IP technology.For the data service of 2G/3G and WiFi, Internet, all filtering classification mechanism is all based on the content of packet, or DSCP (DS) field in IP head, or the relevant field of other agreement on IP.But in LTE core network, data are encapsulated in GTP data tunnel to be transmitted, and the IP head of carrying only comprises the essential information for route of gateway and base station, is limited to the IP head of carrying, the just DSCP(DS that can change) field.So solution of the present invention is as follows, when downlink data enters IAD, if DSCP(DS in packet) field do not arrange (or not correctly arrange), and before not carrying out tunnel encapsulation, according to the content of data packet transmission, by transmission packet IP head in DSCP(DS) field through design mapping relations, the dscp field of LTE core network packet is set, and then carry out tunnel encapsulation, the setting of dscp field is added in the IP head of carrying.When upstream data enters IAD, as long as the IP head of LTE core network packet and GTP head part are peeled off, namely the business data packet that in reducible compartment, user is original, simultaneously according to the far-end IP address in the business data packet after reduction and DSCP(DS) field cog region separates heterogeneous network and type of service thereof.

In addition, this gateway device can further include: Routing Forward Module, when carrying out downlink data forwarding, business datum packaged for protocol conversion module is mapped to and has in the TD-LTE carrying of different Q CI, and provide routing function according to far-end IP address to the user terminal in compartment; When carrying out upstream data forwarding, the business that protocol conversion module is distinguished by Routing Forward Module is forwarded to corresponding heterogeneous network.

In addition, this gateway device can further include: network address conversion module, for when Routing Forward Module carries out upstream data forwarding, carrying out network address translation (NAT conversion) by distinguishing before the business obtained is forwarded to corresponding heterogeneous network to distinguishing the business obtained, convert the address of corresponding network side to; And for when forwarding module down forwards, before distributing the TD-LTE Business Stream mapped, anti-network address translation is carried out to the Business Stream of configuration, convert the IP address of TD-LTE network internal carrying to.

In addition, this gateway device can further include: start initialization module, when gateway device accesses in TD-LTE network, by DHCP agreement, obtains the IP address distributed from PDN-GW, produces and be connected with the acquiescence of TD-LTE network; Carry out initialization connection at network side simultaneously, be connected respectively to the on-site 2G/3G Access Network of IAD, WiFi server, video equipment.

Introduce example multimodality gateway of the present invention below in the data interaction of high-speed railway TD-LTE wide-band communication system and handling process.For compartment, user initiates business, and as shown in Figure 5, the interaction flow relating to multimodality gateway is specific as follows for the handling process of whole high-speed railway TD-LTE wide-band communication system:

(1) multimodality gateway enters TD-LTE network, sets up initial service flow with TD-LTE core network element PDN-GW, and by DHCP agreement, from the IP pond that TD-LTE network is pre-set, obtains an IP address;

(2) multimodality gateway carries out initialization connection at network side, produces acquiescence respectively and is connected to the on-site 2G/3G Access Network of IAD, WiFi server, video equipment;

(3) access point of compartment user in In-vehicle networking, vehicular control unit, LTE system, multimodality gateway apply for IP address in the ground heterogeneous network belonging to user, multimodality gateway carries out DHCP RELAY and DHCP relay, be connected to the Dynamic Host Configuration Protocol server in the heterogeneous network of ground, obtain the IP address of compartment user, the present invention is also referred to as far-end IP address;

(4) after compartment user obtains IP address, can be forwarded by the identification of the type of service of the access of In-vehicle networking, vehicular control unit to the transparent transmission of the mapping of QCI, LTE system, multimodality gateway, carry out business data transmission with corresponding ground heterogeneous network;

(5) for multimodality gateway, the flow process of upstream data and downlink data is different: to upstream data, according to the mark of upstream data service, from the information of TD-LTE form, isolate 2G/3G, WiFi and video monitoring service data and be forwarded to corresponding ground heterogeneous network; To downlink data, the QoS demand of heterogeneous-network service is mapped to QoS grades different in TD-LTE network by the mark according to agreement, again downlink data being packaged into TD-LTE packet and being mapped to has in the TD-LTE carrying of different Q CI, and routing forwarding is to compartment user.

Concrete, the flow chart of data processing of multimodality gateway is divided into upstream data and downlink data process two kinds of situations.As shown in Figure 6, concrete steps are as follows for upstream data handling process:

(1) multimodality gateway receives the data from TD-LTE carrying.

(2) resolve the packet header of business data packet, the IP head of LTE core network packet and GTP head part are peeled off, extracts QCI parameter and object IP address.Flow process in composition graphs 5, before business datum is carried in TD-LTE carrying, vehicular control unit is mapped as QCI type of service, and the object IP address marking data is ground heterogeneous network equipment.

(3) according to QCI parameter, the QCI mapping table of control design, judges type of service, according to IP address and mark thereof, thus judges the heterogeneous network belonging to business.

(4) for different heterogeneous networks, packet is formed the Frame of corresponding form at the link layer of protocol stack, and by Data dissemination to 2G/3G network, WiFi network, video equipment.

As shown in Figure 7, concrete steps are as follows for downlink data handling process:

(1) multimodality gateway receives the business datum from 2G/3G network, WiFi network, video equipment, is referred to as heterogeneous network data.

(2) the QCI information of heterogeneous network packet is extracted, identification services type, and according to the QCI mapping table designed by the QCI parameter of heterogeneous-network service Type mapping to TD-LTE network.

(3) heterogeneous network packet is added to the IP head of TD-LTE core network tunnels agreement GTP packet header and carrying, and in IP head, add the QCI parameter mapped.

(4) packaged TD-LTE network packet is mapped to TD-LTE carrying, carries out routing forwarding.

By above-mentioned process, multimodality gateway of the present invention effectively can solve high-speed railway TD-LTE wide-band communication system to the support of other heterogeneous-network services of 2G/3G, Internet, the identification realizing business datum is simply and easily distinguished and is forwarded to corresponding heterogeneous network, and support that the business datum of heterogeneous network converges to TD-LTE network, thus ensure the two-way communication that business datum is correct.

Non-elaborated part of the present invention belongs to techniques well known.

The above; be only part embodiment of the present invention, but protection scope of the present invention is not limited thereto, any those skilled in the art are in the technical scope that the present invention discloses; the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.

Claims (5)

1. be applicable to a multimodality gateway for high-speed railway TD-LTE wide-band communication system, it is characterized in that comprising: protocol conversion module, Routing Forward Module, network address conversion module and startup initialization module; Wherein:

Protocol conversion module, receives the data input that Routing Forward Module transmission comes, provides unified data format, be convenient to addressing and forwarding at up or down direction for Routing Forward Module; At the service connection that 2G/3G and Internet many kinds of heterogeneous networks are produced under the scene of high-speed railway TD-LTE wide-band communication system, first according to the mark of class of business, the QoS demand of heterogeneous-network service is mapped to QoS grades different in TD-LTE network, again downlink data is packaged into the form of TD-LTE frame, obtain packaged business datum, pass to Routing Forward Module; When the user terminal on train by high-speed railway TD-LTE wide-band communication system be linked into ground heterogeneous network communicate with peer-entities time, according to the mark of upstream data service, from the information of TD-LTE form, isolate 2G/3G, WiFi and video monitoring service data, pass to Routing Forward Module; Described downlink data refers to that heterogeneous-network service is connected to the business datum that high-speed railway TD-LTE wide-band communication system sends user terminal in compartment to; Described upstream data refers to that in compartment, user terminal is linked into through high-speed railway TD-LTE wide-band communication system the business datum that ground heterogeneous network sends peer-entities to;

Routing Forward Module, receive the IP address after the conversion of network address conversion module input, when carrying out downlink data forwarding, business datum packaged for protocol conversion module is mapped in the TD-LTE carrying with different QoS Level Identifier QCI, and provides routing function to the user terminal in compartment; When carrying out upstream data forwarding, by 2G/3G, the WiFi after protocol conversion module conversion and video monitoring service data, be forwarded to corresponding heterogeneous network;

Network address conversion module, receives the IP address that initialization module produces, and for when Routing Forward Module carries out upstream data forwarding, is carrying out network address translation by distinguishing before the business obtained is forwarded to corresponding user to distinguishing the business obtained; And for when Routing Forward Module carries out downlink data forwarding, before distributing the TD-LTE Business Stream mapped, anti-network address translation is carried out to the Business Stream of configuration; IP address after conversion passes to Routing Forward Module;

Initialization module, when gateway device accesses in TD-LTE network, by DHCP agreement, obtains the IP address distributed, produces and be connected with the acquiescence of TD-LTE network from PDN-GW; Carry out initialization connection at network side simultaneously, be connected respectively to the on-site 2G/3G Access Network of IAD, WiFi server and video equipment; In this module, the distribution of IP address is the initial procedure that all the other modules normally work, and IP address passes to network address conversion module as input.

2. the multimodality gateway being applicable to high-speed railway TD-LTE wide-band communication system according to claim 1, is characterized in that: described network side refers to heterogeneous network 2G/3G network, WiFi network or Internet.

3. utilize the cut-in method being applicable to the multimodality gateway of high-speed railway TD-LTE wide-band communication system described in claim 1, it is characterized in that performing step is as follows:

(1) multimodality gateway enters TD-LTE network, sets up initial service flow with TD-LTE core network element PDN-GW, and by DHCP agreement, from the IP pond that TD-LTE network is pre-set, obtains an IP address;

(2) multimodality gateway carries out initialization connection at network side, produces acquiescence respectively and is connected to the on-site 2G/3G Access Network of IAD, WiFi server, video equipment;

(3) access point of compartment user in In-vehicle networking, vehicular control unit, LTE system, multimodality gateway apply for IP address in the ground heterogeneous network belonging to user, multimodality gateway carries out DHCP RELAY and DHCP relay, be connected to the Dynamic Host Configuration Protocol server in the heterogeneous network of ground, obtain the IP address of compartment user, also referred to as far-end IP address;

(4) after compartment user obtains IP address, forwarded to the identification of the transparent transmission of the mapping of QCI, LTE system, multimodality gateway by the access of In-vehicle networking, the type of service of vehicular control unit, carry out business data transmission with corresponding ground heterogeneous network;

(5) for multimodality gateway, the flow process of upstream data and downlink data is different: to upstream data, according to the mark of upstream data service, from the information of TD-LTE form, isolate 2G/3G, WiFi and video monitoring service data and be forwarded to corresponding ground heterogeneous network; To downlink data, the QoS demand of heterogeneous-network service is mapped to QoS grades different in TD-LTE network by the mark according to agreement, again downlink data being packaged into TD-LTE packet and being mapped to has in the TD-LTE carrying of different Q CI, and routing forwarding is to compartment user.

4. method according to claim 3, is characterized in that: described upstream data process flow steps is as follows:

(11) multimodality gateway receives the data from TD-LTE carrying;

(12) resolve the packet header of business data packet, the IP head of LTE core network packet and GTP head part are peeled off, extracts QCI parameter and object IP address; Before business datum is carried in TD-LTE carrying, vehicular control unit is mapped as QCI type of service, and the object IP address marking data is ground heterogeneous network equipment;

(13) according to QCI parameter, the QCI mapping table of control design, judges type of service; According to IP address and mark thereof, the heterogeneous network belonging to business is judged;

(14) for different heterogeneous networks, packet is formed the Frame of corresponding form at the link layer of protocol stack, and by Data dissemination to 2G/3G network, WiFi network, video equipment.

5. method according to claim 3, is characterized in that: described downlink data process flow steps is as follows:

(21) multimodality gateway receives the business datum from 2G/3G network, WiFi network, video equipment, is referred to as heterogeneous network data;

(22) the QCI information of heterogeneous network packet is extracted, identification services type, and according to the QCI mapping table designed by the QCI parameter of heterogeneous-network service Type mapping to TD-LTE network;

(23) heterogeneous network packet is added to the IP head of TD-LTE core network tunnels agreement GTP packet header and carrying, and in IP head, add the QCI parameter mapped;

(24) packaged TD-LTE network packet is mapped to TD-LTE carrying, carries out routing forwarding.