EP1493254A2

EP1493254A2 - Method for the transmission of information via ip networks

Info

Publication number: EP1493254A2
Application number: EP03722363A
Authority: EP
Inventors: Ramin Mirbaha; Vahid Mirbaha
Original assignee: fg microtec GmbH
Current assignee: fg microtec GmbH
Priority date: 2002-04-05
Filing date: 2003-03-27
Publication date: 2005-01-05
Also published as: DE10215151A1; WO2003085920A3; CN1647465A; US20050169237A1; WO2003085920A2; AU2003229577A8; CN100591032C; AU2003229577A1

Abstract

From an abstract perspective, the invention relates to 2 components. One component is arranged on a mobile terminal, information corresponding to the GPRS standard being embedded in IP packets in order to be transmitted to the second inventive component via an IP tunnel. Said second component represents an IP serving GPRS support node (IP-SGSN) in the IP network, which receives the packets from the tunnel and unpacks said packets so as to subsequently send them on to another GSN, for example. Said additional GSN is responsible for other mobile terminals or makes it possible to establish a connection to the internet (GGSN). The second component consequently has the form of a conventional SGSN towards the outside for additional GSN while being considered as the end of a tunnel in the direction of the mobile terminal.

Description

Process for the transmission of information over IP networks

description

The invention relates to a method for the transmission of information via IP networks. In particular, a method for transmitting information through mobile devices, such as mobile telephones or PDAs, which, among other things, have access to conventional radio networks such as GSM or UMTS. If these devices work in a pure IP-based network, such as UMTS or ireless LAN, it makes sense to take up existing standards, on the one hand to achieve a simple transition to existing technologies and on the other hand to enable the user to use them easily.

GPRS for GSM and UMTS enable a packet-oriented network based on UMTS and GSM on the last mile. The advantage of the so-called packet-oriented domains is their compatibility with each other and with the Internet. There are a number of applications that have been specially developed for IP-based networks. This approach shows that GPRS will be a very important part of new UMTS networks. Due to the limitations of UMTS in very busy areas such as For example, in the area of a company or university, UMTS will not meet all requirements. So it will be almost impossible for a provider to do all tasks with one UMTS-GSM network to solve. In such areas, e.g. B. Wireless LAN (IEEE802.11 (x), ETSI Hiperlan) are moving in to relieve the UMTS infrastructure. In such a mixed architecture it is important that communication between the different domains is possible.

The object of the invention is to provide a method and a device that allow interoperability, regardless of the type of network in which the mobile user is located.

This object is achieved by the inventions according to the features of the independent claims. Advantageous developments of the inventions are characterized in the subclaims.

In abstract terms, the invention consists of two components. One component is arranged on the mobile terminal, information being embedded in IP packets in accordance with the GPRS standard in order to transmit it through an IP tunnel to the second component of the invention. This second component is an IP Serving GPRS Support Node (IP-SGSN) in the IP network, which receives the packets from the tunnel and unpacks them. B. to send to another GSN, which in turn is responsible for other mobile devices or via which a connection to the Internet is made possible (GGSN). The second component thus has the form of a conventional SGSN for additional GSNs, whereby it is to be regarded as the end of a tunnel in the direction of the mobile terminal. When information is tunneled, packets of another protocol are packed into an IP packet, so that a complete packet, in this case GPRS packet, can be found in the data area of the IP packet.

Specifically, it is a method for the transmission of information by means of GPRS in an IP network, in particular a wireless LAN and / or a Hiperlan Network, with a preferably mobile terminal that is connected to the IP network so that IP packets can be exchanged. Another component of the invention is an IP Serving GPRS Support Node in the IP network, a tunnel based on IP packets being built when the connection between the terminal and the IP Serving GPRS Support Node is initialized, the tunneling GPRS information. In the following, information is transmitted through the tunnel. The IP Serving GPRS Support Node is connected to other Serving GPRS Support Nodes, Gateway GPRS, Support Nodes and other GPRS Service Nodes (e.g. for SMS) via an IP network, whereby the IP SGSN provides the information depending on the direction of communication unpacked and / or repacked to send the information to the other GPRS service nodes, or packed to send the information through the tunnel to the terminal.

Due to the peculiarity of this method, additional software must be installed on conventional mobile devices that transparently handles the packing and unpacking of information for the user. Furthermore, this software is designed in such a way that it tries to find an IP SGSN as soon as it can establish contact with an IP network. This software is designed so that tunneled GPRS information can be unpacked and packed.

When the connection is initialized, it is checked whether the mobile terminal may have access to a GPRS network, known security checks taking place based on the GPRS mode. This authentication is also achieved by transmission of tunneled information. A corresponding module, as described below, is part of the software. However, it is also conceivable that the software intervenes in the existing authentication methods on the mobile end devices, so that no separate module is required. To establish a connection, a broadcast message is preferably sent in order to find an IP serving GPRS support node in the IP network through which a tunnel is established.

In a preferred embodiment, there may also be an HLR service which is based both on the IP address of the terminal and on other GPRS-typical information (which is stored on the mobile terminal, for example in the form of a Subscriber Identity Module -SIM- authorization) and / or localization of the terminal is permitted. Such an HLR service has the task of determining or storing where a mobile terminal is and to whom it or which telephone number is assigned. In addition, the network provider uses the HLR service to assign user and / or device-specific rights, which due to the special nature of this method can also be used in non-GSM / UMTS networks.

With mobile networks in particular, it is important how a handover between the base stations can take place. Such a handover always takes place when the mobile terminal comes from the reception area of one base station into the reception area of another base station. In the preferred embodiment, a hand over can take place both at the IP level and at the GPRS level. The form of the handover takes place depending on the network in which the end device is located or which network types are switched. If the mobile device z. B. remain in the area of a wireless network, the hand over is preferably carried out on an IP basis. If, on the other hand, the domains are changed, the handover can be based on GPRS. As a special feature, this application uses a mechanism that predicts the future development of the connection quality of the various network types. Based on this prediction, the hand over is optimized in time from one network type to another. For mobile and wireless communications, it is advantageous if the information is encrypted. In the preferred embodiment, Ipsec is used at the IP level. However, it is also conceivable to use other encryption methods. Several methods can also be used in parallel.

As already explained above, in addition to the method, a device is part of the invention, which is arranged in the IP network and takes over the function of an IP SGSN there. This is a device for providing GPRS services in an IP network, with means that enable a known functionality of a serving GPRS support node in a GPRS and / or UMTS network. This complete compatibility with known SGSN or GGSN (Gateway GSN) enables communication with existing networks without any great technical effort. However, the special feature of the device is that it communicates with the preferably mobile terminals on the basis of an IP tunnel, GPRS packets being transmitted through the IP tunnel.

As already described above, the IP SGSN can be used in any IP-based network. It is designed in such a way that it can establish connections to SGSN's, GGSN's, HLR's, CGF's in the UMTS / GSM home network. Seen from the UMTS network, it is therefore a normal "3G" SGSN, as specified in the 3GPP documents.

In connection with the adapted HLR service, the IP SGSN can route different services to different servers. (e.g. Internet and e-mail to the "local" proxy and mail server, or other GPRS services to GGSN of the UMTS / GSM provider).

The specific HLR and CGF are not essential

Components for "GPRS over an IP based network". Rather, they enable additional functionalities that the network provider would like to offer its customers. The adapted HLR works like a well-known transparent one

HLR in the IP based network. He has a list of everyone

Holders that allow roaming. These are HLRs from UMTS / GSM providers that have concluded a roaming agreement with each other. Thus, the IP SGSN asks the adapted HLR instead of another. The adapted HLR decides whether the packet should be sent from the IP SGSN to an HLR, and if so, which one. The provider can also manage its own subscriber list in the customized HLR. Furthermore, the provider can use this HLR

Manage list in which the services offered that the

Users are available, are saved.

The adapted CGF also works transparently like a well-known CGF, but in the IP-based network. This makes it possible to collect information that enables the user to calculate the costs or fees. Instead of establishing a connection to a conventional CFG, the IP SGSN establishes a connection to the adapted CGF. The CGF modified in this way can forward the information to the provider or carry out its own calculations.

In a preferred embodiment, the device has means that provide gateway functionality, in particular the routing of information into other networks. In this case it is an IP-GGSN. Corresponding systems are known from the other networks.

As already explained above, the device can also take over the functionality of an HLR. It should be mentioned here in particular that means are available which allow the mapping of an IP address in an HLR. Furthermore, means are available that allow hand over at the different protocol levels and protocols, as well as means that enable encryption. Other components of the device are means that can receive broadcast messages from a terminal in order to set up a GPRS tunnel connection. After receiving such a packet, a response is sent to the mobile terminal, from which the mobile terminal can see that an IP SGSN is in the network.

Another component of the invention is a terminal that is able to communicate with the IP SGSN through a tunnel connection. However, conventional end devices, such as PDAs or mobile telephones, do not have such functionalities. Rather, it is necessary to adapt the software and possibly the hardware in order to enable such communication. Essentially, these modified end devices have means that enable an exchange of information via GPRS through an IP tunnel. The prerequisite is, of course, that an appropriate IP SGSN is available for communication.

In a preferred embodiment, it is a device that supports several radio standards. The device can preferably support both wireless LAN and UMTS or GSM / GPRS.

Because of the use in IP networks, known methods for address conversion should be implemented. This allows greater flexibility when used in networks that e.g. B. support different IP versions. Address conversion should be allowed, especially from IPv4 to IPvβ and vice versa, and NAT or masking of addresses.

Furthermore, in the preferred embodiment, means are available which allow the information to be encrypted. Encryption options have already been discussed above. Especially during initialization, it is important that means are available that enable authentication in the GPRS network. One access the HLR is preferably carried out here. This approach makes it possible to clearly assign costs.

In the preferred embodiment, a software layer is available which enables the described functionality, which preferably has access to an IP stack. By tapping or redirecting the information in the IP stack that is used in GPRS or. UMTS terminals are available, a simple implementation can be done.

Another component of the invention is software that implements the functionality described on a conventional terminal. It should be noted that the protection should also extend to a data carrier with such software.

With this approach you can easily integrate new network types into existing networks. The functionality of the known networks can still be used, whereby new technologies can be used that are provided by the new networks.

The invention is explained in more detail below on the basis of exemplary embodiments which are illustrated schematically in the figures. The same reference numbers in the individual figures denote the same elements. In detail shows:

1 shows a mobile terminal that supports 3 bands, namely UMTS, GSM and WLAN, which are each used in different domains, the mobile terminal being connected to SGSN via base stations, which in turn establish the connection to different domains via GGSN; Fig. 2 shows a hierarchy starting with terminals (UE) via base stations (UTRAN), (serving) radio network controller, SGSN, GGSN, and HLR

3 shows a logical architecture of a (UMTS) GPRS network;

Fig. 4 user levels for GPRS over GSM;

Fig. 5 user levels for GPRS over UMTS;

Fig. 6 user levels for GPRS over IP;

Fig. 7 control levels for GPRS over GSM;

Fig. 8 control levels for GPRS over UMTS;

Fig. 9 control levels for GPRS over IP;

Fig. 10 Structure of the software module, which is arranged on a mobile terminal.

Fig. 1 shows a mobile terminal that supports 3 bands, namely UMTS, GSM and WLAN, which are each used in different domains. The mobile device moves through the networks, roaming via GPRS. To ensure this, appropriate gateways (GGSN) must be used to establish the connection between the networks. The IP SGSN (fm SGSN) according to the invention, which communicates with the terminal device via an IP tunnel, is used in the network in which the WLAN is used. For further communication, the information is transported via the SGSN and GGSN.

2 shows a hierarchy as found in known (UMTS) networks. Details on this can be found in the literature [13]. The hierarchy starts with a terminal (UE), which is connected to SGSN, GGSN by radio via base stations (UTRAN), via a serving) radio network controller (SRNC). The SGSN and GGSN have access to the HLR. The radio network controller has the task of distributing the bandwidth and frequencies or timeslots.

FIG. 3 shows a logical architecture of a GPRS network, as is known from [13]. From this it can be seen that the network essentially consists of the SGSN and the GGSN, which on the one hand control the connection of the mobile end devices in the domains and on the other hand enable the connection to other networks. There can be several GGSNs in a network that are connected to each other. The SMS-GMSC and SMS-IWMSC are units that are used for SMS exchange. Further details can be found in [13].

FIGS. 4, 5 and 6 show the user levels of the known GPRS via GSM / UMTS protocol and of the GPRS protocol tunneled via IP. In this connection, reference is made to the literature [13]. It is clear that the tunneled protocol GTP-U in FIG. 6 is used both between the GGSN and between the terminal. This is used to transport the IP packets. Only the GTP-U protocol on a UDP / IP layer is used. In contrast to UMTS, there is no need for base stations that additionally communicate with the end device via the Packet Data Convergence Protocol. There is therefore a direct tunnel to the terminal. For further details, reference is made to the literature [20].

Figures 7, 8 and 9 show the differences at the control level.

Another level is Radio Access Network Application

Protocoll (RANAP) used, as described in [20]. This protocol encapsulates and transports Information and signals at higher levels. The levels below RANAP are described in [14]. SCCP should be used to transport RANAP information. This should conform to the ITU-T white book.

The present invention is essentially based on one

Server and a client. Both the client and the server must support GPRS over IP.

The client's modules support a number of new standards such as (3GPP specs, IETF RFCs) or drafts, which are not part of the IP stack, but are based on it. The modular approach has the advantage that simple adaptation is possible.

The structure of the client can be seen in FIG. 10.

The authenticator is responsible for the management of various information such as passwords, public and private keys, certificates and USIM. It also includes authentication methods. For GPRS over IP based networks, authentication according to the GSM and UMTS standards as disclosed in [10] and [25] is necessary.

The security agent is responsible for the security and integrity of the connection. It uses encryption methods and packet-based filters and firewall mechanisms. For GPRS over IP based networks, IPSec should be supported with IKE (Internet Key Exchange, [28]).

In addition to the two modules, there are other modules namely the tunnel manager and the address converter.

The tunnel manager is responsible for tunnel management and handover of tunnel endpoints. GTP ([22]) should be supported for GPRS over IP based networks. The address converter has the task of address conversion, usually from Ipv4 to Ipv6 ([30]) and vice versa. This is necessary because the stacks of the end devices only support version 4. Older networks are also geared towards the older versions. In contrast, newer networks, such as UMTS, will be based on the newer versions. In particular, if handover takes place between the different networks, conversion is necessary. Support for masking or address translation is also of interest ([29]).

List of literature:

[1] GSM 01.61, General Packet Radio Service (GPRS); GPRS ciphering algorithm requirements [2] GSM 03.40, Technical Realization of the Short Message

Service (SMS) Point-to-poin (PP) [3] GSM 04.08, Mobile radio interface layer 3 specification [4] GSM 04.60, General Packet Radio Service (GPRS);

Mobile Station (MS) - Base Station System (BSS) interface; Radio Link Control / Medium Access Control

(RLC / MAC) protocol [5] GSM 04.64, General Packet Radio Service (GPRS);

Mobile Station - Serving GPRS Support Node (MS-SGSN)

Logical Link Control (LLC) layer specification [6] GSM 04.65, General Packet Radio Service (GPRS);

Mobile Station (MS) - Serving GPRS Support Node

(SGSN); Subnetwork Dependent Convergence Protocol

(SNDCP)

[7] GSM 08.16, General Packet Radio Service (GPRS); base

Station System (BSS) - Serving GPRS Support Node

(SGSN) interface; Network service

[8] GSM 08.18, General Packet Radio Service (GPRS); base

Station System (BSS) - Serving GPRS Support Node

(SGSN); BSS GPRS Protocol

[9] GSM 09.02, Mobile Application Part (MAP)

Specification

[10] 3GPP TS 23.003 v5.1.0, numbering, addressing and

Identification

[11] 3GPP TS 23.015 v4.0.0, technical realization of

Operator Determined Barring (ODB)

[12] 3GPP TS 23.040 v5.1.0, Technical realization of Short

Message Service (SMS)

[13] 3GPP TS 23.060 v4.2.0, General Packet Radio Service

(GPRS) service description; Stage 2

[14] 3GPP TS 23.121 v3.5.1, Architecture Requirements for release 99

[15] 3GPP TS 24.008 v5.1.0, Mobile radio interface Layer 3 specification; Core network protocols; Stage 3

[16] 3GPP TS 25.301 v4.1.0, Radio Interface Protocol

Architecture

[17] 3GPP TS 25.321 v4.2.0, Medium Access Control (MAC) protocol specification

[18] 3GPP TS 25.322 v4.2.0, Radio Link Control (RLC) protocol specification

[19] 3GPP TS 25.323 v4.2.0, Packet Data Convergence

Protocol (PDCP) specification

[20] 3GPP TS 25.413 v4.2.0, UTRAN Iu interface RANAP signaling

[21] 3GPP TS 29.002 v4.5.0, Mobile Application Part (MAP) specification

[22] 3GPP TS 29.060 v4.2.0, General Packet Radio Service (GPRS); GPRS Tunneling Protocol (GTP) across the Gn and Gp interface [23] 3GPP TS 29.061 v4.2.0, Interworking between the

Public Land Mobile Network (PLMN) supporting packet

Based Services and Packet Data Networks (PDN [24] 3GPP TS 32.215 v4.0.0, Telecom Management; Charging management; Charging data description for the packet

Switched (PS) domain [25] 3GPP TS 33.102 v4.2.0, 3G security; Security architecture

[26] RFC 2002, IP Mobility Support

[27] RFC 2284, PPP Extensible Authentication Protocol

(EAP)

[28] RFC 2409, The Internet Key Exchange (IKE)

[29] RFC 3022, Traditional IP Network Address Translator

[30] RFC 3089, A SOCKS-based IPv6 / IPv4 gateway mechanism

Claims

claims

1. Method for transmitting information by means of GPRS in an IP network, in particular a wireless LAN and / or a Hiperlan network, with a preferably mobile terminal that is connected to the IP network, so that IP packets can be exchanged , with an IP Serving GPRS Support Node in the IP network, - whereby when the connection between the end device and the IP Serving GPRS Support Node is initialized, a tunnel is built based on IP packets that tunnels GPRS information,

- whereby the transmission of information takes place through the tunnel,

- whereby the IP Serving GPRS Support Node is connected to other Serving GPRS Support Nodes via a network, and unpacks and / or repackages the information depending on the direction of communication in order to send the information to the other Serving GPRS Support Nodes or wraps it around Send information through the tunnel to the terminal.

2. The method according to the preceding method claim, characterized in that software is installed on the mobile terminal that unpacks tunneled GPRS information.

3. The method according to the preceding method claim, characterized in that when the connection is initialized it is checked whether the mobile terminal may have access to a GPRS network, known security checks taking place based on the GPRS mode.

, Method according to the preceding method claim, characterized in that an IP serving GPRS support node is searched in the IP network by broadcast messages in order to establish a tunnel.

5. The method according to one or more of the preceding method claims, characterized in that an HLR service is available which allows determination and / or localization of the terminal device both on the basis of the IP address of the terminal device and on the address information from GPRS

6. The method according to one or more of the preceding claims, characterized in that a hand over can take place both at the IP level and at the GPRS level, depending on the network in which the terminal is located.

7. The method according to one or more of the preceding claims, characterized in that encryption at GPRS and / or IP level, preferably by ipsec, takes place.

8. Device for providing GPRS services in an IP network, with means that enable the functionality of a serving GPRS support node in a GPRS and / or UMTS, characterized in that means are available that allow communication via GPRS through a Allow IP tunnels with one device.

9. Device according to the preceding device claim, characterized in that means are available which allow gateway functionality, in particular the routing of information into other networks.

10. The device according to one or more of the preceding device claims, characterized in that Means are available that allow the mapping of an IP address in an HLR.

11. The device according to one or more of the preceding device claims, characterized in that means are provided by which a hand over can take place both at the IP level and at the GPRS level, depending on the network in which the terminal is located.

12. The device according to one or more of the preceding device claims, characterized in that

Means are available that enable encryption on the GPRS and / or IP level, preferably by ipsec.

13. The device according to one or more of the preceding device claims, characterized in that means are provided which can receive broadcast messages from a terminal in order to thereby set up a GPRS tunnel connection.

14. Terminal with means for communication in an IP network, in particular a mobile terminal, characterized by means that enable an exchange of information via GPRS through an IP tunnel.

15. Terminal according to the previous terminal claim, characterized in that the terminal supports both wireless LAN and UMTS and / or GSM.

16. Terminal according to one or more of the previous terminal claims, characterized in that means are available which allow address conversion, in particular from IPv4 to IPv6 and vice versa, and NAT and / or masking.

17. Terminal according to one or more of the preceding terminal claims, characterized in that means are provided which enable the tunneled information to be encrypted or encrypt the tunnel packets themselves, Ipsec preferably being used.

18. Terminal according to one or more of the previous terminal claims, characterized in that means are available which enable authentication in the GPRS network.

19. Terminal according to one or more of the preceding device claims, characterized in that a software layer is present which enables the described functionality, which preferably has access to an IP stack.

20. Software for a terminal in an IP network, in particular a mobile terminal such as a PDA or a mobile telephone, characterized in that a process is implemented which enables information to be exchanged via GPRS through an IP tunnel.

21. A data carrier with a data structure that can be loaded into a terminal, the data structure comprising the software according to the preceding claim.