Method and device for broadcast in point-to-point packet networks

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DESCRIPTION

Method and device for broadcasting in point-to-point packet networks.

Technical field of the invention

The present invention relates to a method, broadcast management center, router or "router", central computer and system for broadcasting in a point-to-point oriented packet-switched telecommunication network.

Background

Broadcasting allows the possibility of directing a packet to all destinations using a special code in the address field. When a packet with this code is transmitted, it is received and processed by every user on the network. After receiving a packet and if a user does not try to receive the message, it discards the received packets. In contrast to this point-to-point communication it involves sending a message from a single sender to a single receiver. Some broadcast systems also support broadcasting to a subset of users, the so-called multicast. Multicast is a service that allows sources to send a single copy of the same data to one address causing the data to be sent to multiple receivers, which are registered to a multicast group. Therefore multicasting is a form of broadcasting. The difference is that in the event that the broadcast does not require the user to register to any group, the message is distributed to all users.

In broadcast and also in multicast only one copy of a message passes over any link in a network and copies of the message are made only where the paths diverge. From a network perspective, broadcasting dramatically reduces total bandwidth consumption as data is duplicated across the network at the appropriate points rather than at end systems. Furthermore, a server, which is sending broadcast messages, needs to manage only one session.

The Internet Protocol multicast registration procedure will be discussed in more detail below.

In the case where multicast is used in the IP Internet Protocol network then it is called IP multicast. Among other features that characterize IP multicasting, a specific way of addressing is applied using the existing IP address, such as the so-called D address in IP version 4.

Within IP multicast the membership of a multicast session group is dynamic which means that the hosts join and leave the groups at any time. To allow hosts on networks to indicate whether they want to join or leave a particular multicast group there is a protocol called IGMP Internet Group Message Protocol. In this way this protocol allows the system to know which hosts currently belong to which multicast groups. This information is required by multicast routers or routers to know which multicast data packet is going to be forwarded on which interface.

IGMP is a part of the IP layer and IGMP messages are transmitted in IP data packets. IGMP version 1 is described in RFC 1112 "Host Extensions for IP Multicast" SE Deering, August 1, 1989, RFC 2236 "Internet Group Management Protocol, Version 2" W. Fenner, November 1997 describes version 2. IGMP has been developed for IP version 4. In IP Internet Protocol version 6 there is a protocol called MLD Multicast Listener Discovery, which is used for the same purpose as IGMP. MLD provides more functionality than IGMP. The description of the first version of MLD can be found in RFC 2710 "Multicast Listener Discovery (MLD) for IPv6" S.Deering, W. Fenner, B. Haberman, October 1999. However, the messages used in MLD correspond to IGMP messages. IGMP will be used as an example below. Although this should not be restricted to IGMP, the functionality of the invention is also provided through the use of MLD.

In principle, IGMP uses two basic messages to complete its tasks, the membership report and the membership inquiry message, and the following rules apply.

A multicast router or router sends a membership query at regular intervals to see if any host still belongs to any group. The router or "router" must send a query out of each interface. A host responds to a membership query by sending a membership report for each group that still contains at least one process. A host joins a group by also sending the membership report.

Using the information received by applying the report and the query messages, a table is established with its interfaces that has at least one host in a multicast group. After receiving the multicast data the router or "router" forwards the data out on those interfaces, which have at least one member.

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With IP multicast receivers, you do not need to know who or where the senders are to receive traffic from them, and senders never need to know who the senders are. Neither senders nor receivers need to worry about the network topology since the network optimizes delivery. The distribution of information via IP multicast is done on the basis of a hierarchical connection of the hosts, such as a multicast distribution tree. Various algorithms have been proposed to build multicast distribution trees, such as spanning trees, shared trees, source-based trees, and kernel-based trees. Descriptions of the corresponding algorithms can be found in "IP Telephony: Packet-Based Multimedia Communications Systems" O. Hersent, D. Gurle, D. Petit, Addison-Wesley, Harlow, 2000. After the establishment of the multicast cast tree , the distribution of information is done by IP multicast routing protocols. Detailed description of the corresponding IP multicast routing protocols can also be found in the document mentioned above.

In order to explain the problem arising from the introduction of broadcasting in a point-to-point oriented packet switched telecommunication system, a description of the network architecture of the General Packet Radio System GPRS is given below.

GPRS is the packet-switched enhancement of the Global GSM Mobile Communications System, which is a circuit-switched network. This means that the user can be permanently connected online but has to pay only for the actual data transfer. To meet the new requirements, some changes will be introduced in GSM. Among others, new logical nodes will be introduced, the SGSN Service GPRS Support Node and the GGSN Gateway GPRS Support Node. The main functions of the GGSN involve interaction with external IP packet networks that provide connections to Internet Service Providers ISPs through the Gi interface. The SGSN serves all GPRS subscribers that are physically located within the SGSN geographic service area. It communicates through the Gn interface, which defines the IP-based trunk, with the GGSN. The IP-based trunk is the GPRS restriction that GGSN and SGSN are to be connected in a way that IP is running on top of the chosen technology, which assumes that the SGSN and GGSN communicate via addresses. IP. This restriction also applies for the Iu-PS interface, which is defined between the SGSN and the Radio Network Controller RNC. The RNC manages the Radio Access Bearers for user data, radio network and mobility. The Radio Base Station also called BTS Transceiver Base Station or simply Base Station BS or in 3GPP, Node B, provides the radio resources and communicates with the user equipment over a Uu interface.

A detailed description of the architecture is to be found in 3GPP TS 03.60 V7.5.0 (01-2001) 3 Cooperation Project^to Generation; Aspects of the System and Services of Technical Specification Groups, Digital Cellular Telecommunications System (Phase 2+), General Packet Radio Service (GPRS), Description of the Service, Stage 2 (Communication 1998).

Similar nodes and interfaces are also used in the next generation of wireless networks, the Universal Mobile Communications System UMTS as described in 3GPP TS 23.060 V3.6.0 (01-2001) 3rd Generation Cooperation Project; Aspects of the System and Services of Groups of Technical specification, General Packet Radio Service (GPRS), Description of the Service, Stage 2 (Communication 1999).

To distinguish between the functionality of these nodes in UMTS, extended names, 3G-SGSN and 3G-GGSN are often used. In the following description no distinction will be made between GPRS and UMTS nodes.

WO-9959355-A discloses a reliable multicast transmission in a communication network comprising a first router or "router", GGSN, at least one host computer, BSS, where the GGSN communicates with a PTN-SC that provides point transmission -multipoint. The document teaches to provide a lifetime multicast message to ensure transmission of only current data to registered users to a multicast group. Furthermore the document provides a mechanism to recognize the received multicast data. In this way, the document concentrates on a reliable multicast, therefore the solution is not applicable for broadcast transmission since the transmission of the acknowledgments causes an additional header to the header caused by the broadcast transmission itself. Furthermore, the provision of broadcasting in a point-to-point oriented telecommunication network is not discussed.

EP-1071296 discloses a method to provide techniques for a multicast transmission between a router or "router" (GGSN) and service nodes (SGSN) in a telecommunication network. Multicast transmission is done by encapsulating an IP packet in a private packet and by routing said private packet at the routing layer. However, a solution for supplying broadcast data to users in a point-to-point oriented telecommunication network is also not disclosed.

Currently broadcasting on mobile networks causes some problems. The consequences of the problems are among other things the mobility of the end users and the low transmission bandwidth of the mobile network at the air interface. Furthermore, communication in mobile communication networks such as UMTS is unicast communication. Unicast communication is also called point-to-point communication. In such type of network, and in particular in the core network, it is not envisaged to carry out broadcast or even multicast communication. Group communication is implemented by means of a point-to-point communication that has a sender who

ES 2 333 703 T3 separately transmits the same packets to each receiver, instead of one packet when broadcast is used. This means that IP broadcast messages are sent from a router or "router" placed in an external IP network, such as the Internet, to the mobile station through a unicast connection, because from the mobile station's point of view the router or " router ”on the Internet is the first node where the IP connection ends and therefore the first applicable node for broadcasting. Therefore broadcasting is done at the application IP layer and the network nodes between the server and the user merely forward the broadcast or multicast messages within the central part of the network without distinguishing between a broadcast message and a unicast message. The existing technology of a point-to-point oriented packet switched telecommunication network such as UMTS does not provide for the use of efficient broadcasting.

Beyond this, broadcasting is fine when only several users share a small LAN, but in larger networks, such as UMTS, where a large number of users are connected through different network nodes, broadcasting becomes a trouble. In particular in mobile networks that send the broadcast information to all users, considerable amounts of network bandwidth are consumed. Furthermore, the user equipment has to check the received information and in case of irrelevant information it has to discard the received packets. This causes inefficient use of network node resources. However, there are many applications, which broadcast in broadcast, for example the broadcasting service on demand, music and video programs, the repetition and visualization of sports with multi-camera angles or dramas with alternative scenery, which are programs, the continuation of which depends on the result of the voting of the recipients.

Often times applications that use broadcast as a form of delivery depend on the geographic location of the user. Disregarding geographic location assumes that broadcast messages are sent to all users regardless of the importance of whether this message might be of interest to the user.

In general, the introduction and implementation of broadcasting in a protocol stack, which is basically point-to-point oriented causes problems, then in such type of networks a unicast channel is established to carry out communication between two nodes.

Summary and description of the invention

It is an object of the present invention to provide a solution for efficient introduction and implementation of broadcast in a point-to-point oriented packet switched telecommunication network. In particular it is an objective of the present invention to make the broadcast dependent on the geographical location of the user.

The invention is carried out in a method, router or "router", broadcast management center, host computer and system as set forth in claims 1, 15, 16, 18 and 19. Advantageous embodiments are described in the dependent claims.

The idea for the purpose of broadcast provision in a point-to-point oriented packet-switched telecommunication network is set forth in claim 1. Said telecommunication network has a set of network nodes, wherein the set comprises a first router or " router ”and at least one host that serves at least one user. The first router or "router" can connect said telecommunication network with an additional network in case a server capable of broadcasting is located in the additional network. It is also possible to have the broadcast capable server located in the point-to-point oriented packet switched telecommunication network. Said telecommunication network can of course have additional network nodes, such as additional routers or "routers" responsible for routing the data to the user. According to claim 1 a broadcast management center configures the network nodes to provide broadcast within a geographic broadcast group. The broadcast capable servers send the broadcast data to the first router or "router." A multicast technique is used at the transport layer to route the broadcast data from the first router or "router" to the host computer that belongs to a certain geographic broadcast group. The host computer uses broadcast techniques to send the broadcast data to the at least one user.

The advantage of the multicast technique in the transmission parts is better utilization of network resources. Broadcast data is not sent to each network node but only to network nodes registered to the geographic group.

In a preferred embodiment of the invention the geographical broadcast group is defined as a geographical area, which is part of a Public Land Mobile Network PLMN. This can be for example a province like Nordrheinwestfalen or a city.

The configuration of the network nodes made by the broadcast management center can be done directly. With this solution the network nodes belonging to a certain geographical area are addressed directly. This guarantees quick setup. However, this implies that the broadcast management center has all the required information about the nodes, which are going to be configured.

In another embodiment of the invention the configuration carried out by the broadcast management center is done indirectly so that a network node is directed to establish the connection to the additional network nodes building the certain geographical area. The advantage is that the broadcast management center manages the information merely

ES 2 333 703 T3 about some network nodes and these nodes have information about additional nodes. By applying this architecture, the responsibility for configuration is delegated to the network nodes.

In the embodiment, in which the configuration is done indirectly, it is advantageous to send a message to the network nodes, which are to be configured and the nodes are registered to the corresponding geographic group. Registration can be done using existing techniques for registering to a multicast group, such as IGMP or MLD.

The configuration of the network nodes is done through an information exchange interface between the broadcast management center and the network nodes. The configuration is merely a part of the information exchange done on that interface. Additional information can be for example the information of requirements related to the Quality of Service QoS.

In a preferred embodiment of the invention, it is envisaged to have an information exchange interface between the broadcast capable server and the broadcast management center to support the broadcast management center with information, for example on the construction of the broadcast geographic group. . For this purpose the server sends information about a geographical area, which could be interested in a certain broadcast application.

The multicast technique at the transport layer uses a transport layer multicast group tunnel, which is established by means of the transport layer protocol for tunneling. This assumes that for example in an IP switched network, which has two IP layers, the application IP layer and the transport IP layer as further described, the multicast or broadcast transmission performed at the application IP layer is assigned to the Transport IP. This actually assumes that multicast or broadcast transmission takes place at the IP layer. The invention proposes to redirect the multicast or broadcast transmission from the application IP layer to the transport IP layer. This can be done using a tunnel established at the IP transport layer for the certain multicast group by means of a transport layer protocol for tunneling, which may preferably be the GPRS GTP Tunneling Protocol.

In a preferred embodiment, data sharing is done in the multicast portion of the transmission using a multicast sharing tree, which can be established by means of the existing multicast routing protocol.

It is advantageous to use IP multicast, due to existing delivery techniques, such as IP routing protocols that use the IP packet header, in which the multicast group identifier is included.

Transmission of the broadcast data from the host computer to the user is done by means of a broadcast technique. In mobile networks this part of the transmission represents a radio interface. In a preferred embodiment of the invention, the broadcasting technique at the radio interface can be implemented by a broadcast bearer, which distributes the same data to all users in a cell.

It is advantageous that the network nodes carry out the allocation of the transmission parts to distribute the broadcast data. For example, the broadcast data delivered from the broadcast-capable server on a broadcast channel in the application IP layer will be assigned in the first router or "router" to the multicast channels built in the transport layer. Additional allocation will be made in an additional router or "router", which sends the received multicast data over an additional multicast channel, which is identified by another address. It may also be possible for an additional router or “router” to only forward the received data. The assignment may cause the channels that identify addresses to be added or replaced. It can also cause packet encapsulation.

Furthermore, a broadcast management center is required for broadcast and / or multicast management within a point-to-point oriented packet switched telecommunication network to carry out the invention according to claim 16. Said network is connected to an additional network with a server capable of broadcasting and has network nodes comprising at least one router or "router" and at least one host computer serving at least one user. The broadcast management center has a configuration unit for configuring the network nodes to a geographic broadcast group. This unit is responsible for defining the network nodes and the parameters required to configure. The configuration is presented to the defined nodes by means of a communication unit. The definition of the geographic broadcast group is based on the information received by a receiving unit. The information can be received from an operator or from the broadcast capable server through an interface between said server and the broadcast management center.

The invention also features a router or "router" adapted to multicast in a point-to-point oriented packet switched telecommunication network connected to an additional network with a broadcast capable server. Said telecommunication network has network nodes comprising at least one of said router or "router" and at least one host computer serving at least one user. The router or "router" has a configuration unit for configuring the network nodes to provide the geographic broadcast group. The configuration can be done both directly in the router or "router" as in the configuration unit it is also required to configure the additional network nodes to a geographical broadcast group. The router or "router" also has a receiving unit to receive data. The data can be both multicast data received from a previous router or "router" and broadcast data received from a broadcast capable server.

ES 2 333 703 T3 located in the additional network. The received data is given to the means to provide multicast techniques at the transmission layer to multicast the data. A sending unit for sending the multicast data sends it to the host computer belonging to the certain geographical broadcast group. This means that it can be both a next router or "router" and a main computer.

In this case the router or "router" has to adapt the received data for further routing according to a data structure that is to be provided for managing the relationship between the received data and the sent multicast data.

Furthermore the invention includes the new functionality of a host computer. The main computer will be adapted to broadcast in a point-to-point oriented packet-switched telecommunication network where the main computer connects on the one hand to at least one router or "router" and on the other hand to at least one user. . The host computer has a receiving unit to receive multicast data. This data is sent from the router or "router" using a multicast technique at the transport layer. After receiving the multicast data, an association unit is used for establishing the association of the reception data to the broadcast data, which is sent to the user. The host computer provides means to deliver the broadcast technique to the user. Depending on the user interface, different diffusion techniques can be used. The data is sent to the user by means of a sending unit.

Furthermore, the invention discloses a system adapted to broadcast in a point-to-point oriented packet switched telecommunication network connected to an additional network with a server capable of broadcasting and said telecommunication network having network nodes comprising at least one router or Router and at least one host that serves at least one user. The system includes at least one router or "router", at least one host computer, and a broadcast management center with the new functionality as described above.

A detailed description of the invention is given below,

Fig. 1: GPRS protocol architecture,

Fig. 2: List of network nodes according to the invention,

Fig. 3: Configuration of the network nodes according to the invention,

Fig. 4: Registration procedure,

Fig. 5: Broadcast data sharing procedure

The following describes the implementation of multicasting in a point-to-point oriented packet switched telecommunication system.

The above-mentioned requirements and the restriction of the functionality and the way of communication of the packet-switched oriented nodes introduced as SGSN or GGSN have their impact on the protocol stacks developed. As a result of the function of the GGSN as a router or "router" and as an interface to external networks, the IP layer has been introduced below the application layer. In addition, due to the restriction of having an IP network within the core network, this implies that an IP layer has been introduced as a means of transport between the GGSN and the SGSN and additional to the RNC, below the specific application tunneling protocol .

The following description merely concentrates on the two IP layers in the packet switched domain with respect to Figure 1. Figure 1 shows a user, MS, connecting over the Uu interface with an access network, UTRAN. This network communicates through the Iu-PS interface with a 3G-SGSN. The 3G-SGSN communicates over the Gn interface with the 3G-GGNS. The Gi interface defines the interface to an additional network, such as the Internet.

With respect to Figure 1 there are two IP layers, represented as IP, PPP and UDP / IP, described below as application IP and transport IP layer. The application IP layer is located directly below the application protocols, Applications, in the protocol stack. The task of this IP layer is to connect the mobile station and the GGSN. This IP layer is transparent to the core network such as the packet switched network. This is represented in Figure 1 by a direct line running from the MS to the 3G-GGSN. The second IP layer is the transport IP layer used for transmission between the SGSN, GGSN and the UTRAN. The payload traffic is transported through the Gn and Iu-PS encapsulated in an application-specific tunneling protocol, the GPRS GTP-U tunneling protocol, which is an example of a transport layer protocol for tunneling, GTP packets use UDP as the transport protocol. However, there are different tunneling protocols, which are responsible for building a tunnel and GTP is merely an example. The other protocols are mentioned in Figure 1 for complementary reasons.

Regarding the architecture of two IP layers presented below, a possible multicast technique in the transport layer is described.

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The multicast technique uses a transport level multicast group tunnel TLMG, which is established by means of the transport layer protocol for tunneling such as GTP. Therefore, in the case of IP multicast, the idea is to assign the multicast performed on the application IP layer to the transport IP layer. At the transport IP layer, a GTP tunnel is established for a multicast group. The tunnel is identified in such a way that a mapping between the multicast data arriving on the Gi interface to the GTP tunnel is guaranteed. The TLMG can be set both on demand, which means when the first multicast member registers to a multicast group, and it can be preset to speed up the initialization procedure. Next, a multicast member describes a network node, which is configured to be a member of a multicast group, which builds a geographic broadcast group.

The establishment of a TLMG tunnel is done as follows.

First the so-called PDP-Context activation is performed. Activating the PDP context is like logging into the external IP network. In this spirit, a multicast member identity is associated with an IP address. During PDP Context Activation a tunnel is created with an identity between the multicast member and the GGSN. During this procedure the QoS Quality of Service negotiation also takes place. To register to a multicast group, the multicast member sends an IGMP membership report message. In case the multicast group as indicated in the IGMP Membership Report does not exist in the GGSN yet, the GGSN creates a new entry for it. Additionally, the GGSN creates a Transport Layer Multicast Group TLMG at the transport IP layer for multicast arriving at the application IP layer. For this purpose the GGSN assigns a multicast address from the address space of the core network. Next it will be called the Multicast IP Address of the TLMG or Alternative TLMG-MC Address or simply TLMG address. To create the appropriate TLMG, the GGSN may take into account the QoS Quality of Service requirements negotiated from the PDP context.

The GGSN informs the corresponding nodes that it has mobile stations that register to a multicast group by means of the enhanced GTP protocol as an example. A new GTP message, SGSN Membership Report Request, can be used. It is also possible to use the existing message, for example an enhanced Packet Data Unit PDU notification message on the UDP connection for this purpose.

The SGSN Membership Report Request message contains the information required for the duplication of the multicast sequence within the multiple unicast sequences at a certain node, such as the TLMG-MC Address and the identification of the multicast member. In this way, for multicast group traffic, the GGSN ignores the tunnel that is already established for that MS by the SGSN during the activation of the PDP context and uses TLGMs, which form a multicast distribution tree. This type of multicast cast tree will be called in the further description a TLMG cast tree. With this method, the GGSN over the Gi interface in the IP application redirects the incoming multicast data from the IP application layer to the IP transport layer, which performs multicast in the central network using the TLMG distribution tree.

A deregistration from a multicast group is done via IGMP and is required by the broadcast management center. For this purpose the multicast member sends an IGMP Leave Message to the GGSN. The GGSN then sends a new GTP message to the multicast member to request membership release. This message is carried as a parameter the TLMG MC Address and the address of the multicast member. Also the GGSN removes the mobile station from the list for the corresponding multicast address or just reduces the corresponding counter. In case this multicast member was the only one registered for the multicast group then the TLMG is released from the TLMG sharing tree.

The described TLMG technique is only an example to perform a multicast technique. In the following the implementation of broadcasting in a point-to-point oriented packet-switched telecommunication network is described in more detail using any multicast technique possible in the core network.

In the following, the transmission of the multicast or broadcast data performed at the application IP layer will be called U-broadcast or U-multicast. Contrary to this the transmission at the IP transport layer will be called T-broadcast or T-multicast. In addition, the multicast or broadcast service on the radio bearer will be called broadcast-R or multicast-R. Due to the fact that the broadcast or multicast at each layer provides a service it will also be called the broadcast or multicast service-U, -T, or -R below. For example a U-broadcast service is a broadcast application provided by the server capable of broadcasting, a T-multicast service can be any multicast technique in the transport layer, which is provided by the network operator and a broadcast R is any broadcast technique on the radio interface.

For the realization of the invention, new nodes or new additional features will be introduced in the existing nodes. Next the new characteristics of a router or "router", in the example of the GGSN, the new characteristics of a main computer, in the example of the RNC / Node B, the new characteristics of the router or "router" capable of broadcasting and the broadcast management center. Next, the router or "router" capable of broadcasting will be called Broadcast / Multicast Server or MC / BC server and the broadcast management center will be called MC / BC Management Center with the meaning that both nodes also support multicast. The relationship of the nodes is described with respect to figure 2.

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Figure 2 shows the geo-broadcast network architecture. Base stations BS connect to the RNC. An SGSN manages the RNCs through the Iu-PS interface and on the other hand connects to the GGSN. The GGSN communicates through the Gi interface with an MC / BC Server. In figure 2 this server is represented as the MC / BCU Server. The MC / BC-U / T Management Center, through an interface that goes to the network nodes involved, manages the entire architecture.

In figure 2 this interface is represented by the dashed line. It shows that a Management Center MC / BCU / T can direct all the nodes within a network for example to carry out the configuration. For the purpose of configuration, messages are exchanged in the form of a request and an acknowledgment message between the MC / BC-U / T Management Center and the corresponding nodes. If there is a corresponding interface, a communication can be made to an MC / BC-U server.

The following describes the enhanced functionality of the GGSN.

To fulfill the new tasks, the GGSN has to act as a local multicast router or "router", which is capable of handling incoming IGMP messages. Normally the nodes register in specific multicast groups in the GGSN and the GGSN keeps track of the active multicast groups in the packet switched network.

Additionally, the GGSN creates the multicast group at the network level, which means from the GGSN to the BTS. This multicast group can be for example the Transport Level Multicast Group TLGM described above. The registration procedure is described in more detail later.

In addition, the new functionality of a main computer is described. In the case of UMTS, the task of a host computer can be performed by an RNC in connection with the BTS or Node B.

If the SGSN is in charge of T-multicasting a service, the SGSN orders the RNCs to T-Multicast and the RNCs in turn order the BTSs or Node Bs to broadcast-R the service. The Node B stores the received broadcast or multicast information and then both waits for the receipt of the T-multicast data stream from the RNC and registers itself to the corresponding T-multicast cast tree. The RNC / Node B assigns the incoming Multicast-T service to an R-broadcast service.

In addition to a packet switched network and network nodes, MC / BCU / T servers, a corresponding MC / BC-U / T Management Center, and a MC / BC-U / T Management Interface are required.

The MC / BC-U / T Management Center is described below.

The MC / BC-U / T Management Center is used to configure the Multicast-T and Broadcast-R services in the PLMN regarding the required -U service. The MC / BC U / T Management Center can have an interface to the MC / BCU Servers to retrieve and send information about the MC / BC-U service that will be used for the management and configuration of the MC / BC-R service. in the PLMN. The information to be retrieved from the MC / BC server can be for example the multicast address of the MC / BC-U service, such that the GGSN can register itself to the corresponding multicast group using this multicast address, and the QoS required for MC / BC-U service. Furthermore, the MC / BC server can send to the MC / BC-U / T Management Center the specification of the geographical area for a certain BC-U Service.

The task of the MC / BC-U / T Management Center can also be fulfilled by any other node, which has the functionality mentioned above.

The following describes the MC / BC-U server.

The MC / BC-U server contains and provides the U-broadcast service to the wireless subscribers in the PLMN. Such a server is normally located on the additional network, such as the Internet, and does not have any information about the structure of the connected networks. The MC / BC-U server merely knows that there is a network with at least one user, who wants to receive the broadcast information. Transmission is done at the application IP layer, hence the -U prefix. However, a U-multicast service or U-unicast service can also be used on the Internet to provide a geographic U-broadcast service in the PLMN if the unicast / U-multicast service is handled in the GGSN as a GGSN service. diffusion-U. The difference is not visible to the end user within the PLMN anyway.

Regarding the introduced nomenclature and the introduced function of existing or new nodes the basic idea of ​​the present invention is therefore to introduce an efficient architecture solution to provide U-broadcast services to all subscribers who are capable and willing to receive the service in a specific geographic area of ​​the PLMN. The provision of the U-broadcast service involves a U-broadcast server, a T-multicast technique on the fixed infrastructure, which builds the core network, and an R-broadcast technique on the radio interface. The U-broadcast service is supported by an MC / BC-U / T management center.

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A preferred embodiment of the invention is given below. She describes the configuration of geographic areas.

U-broadcast geographic services apply to the area covered by a BTS / Node B, RNC, SGSN, GGSN, or the entire PLMN, which means that it consists of nodes in the distribution tree starting at the GGSN in the PLMN. Operators use the MC / BC-U / T Management Center to configure one or more nodes in the PLMN to supply the broadcast-U service. Another possibility for configuration is triggered by the MC / BC server. This assumes that the configuration is based on the parameters retrieved from the MC / BC-U server. This solution will be applied when there is an interface between the MC / BC server and the MC / BC-U / T Management Center.

The MC / BC-U / T Management Center performs the configuration of a node in the PLMN. This can be done both directly and indirectly through any of the nodes higher up in the hierarchy. In the first alternative, the MC / BC-U / T Management Center orders a node to become part of a multicast group T of the PLMN. This means that the MC / BC-U / T Management Center directly configures the BTSs and / or Node Bs so that they become part of the multicast group. This is done with registration through IGMP as described below. The direct configuration of the BTS requires that the nodes higher up the hierarchy be informed about the configuration to distribute the broadcast data to the BTS as described in the broadcast data distribution procedure.

In the second solution, the MC / BC-U / T Management Center configures an intermediate node, such as an SGSN and the SGSN is responsible for establishing the connection to the BTS or Node B. The establishment of the connection can be based on in a multicast cast tree. For this purpose the nodes, which are to be connected, are required to register to the multicast group. The multicast group address is sent with the request message. Therefore, the connection establishment addressed node is also advised by the MC / BC-U / T Management Center of the size of the multicast group, this means by the nodes, which are going to be connected. For example, the MC / BC-U / T Management Center can configure an SGSN that should multicast a specific service in the entire coverage area. The configuration can contain any description from a simple configuration such as the entire zone to more complex configurations such as the entire zone except RNC-4.

Although it is possible to allow the node of the packet-switched network to determine itself the corresponding input nodes such as zones between certain geographic coordinates, the logic to determine the network nodes for T-multicast should generally reside in the Management Center. MC / BC-U / T.

The multicast group registration of the nodes, which are directed to connect, is done by means of multicast group management mechanisms such as IGMP or MLD as described below.

The following is the setup procedure with respect to Figure 3.

Figure 3 includes the following nodes, the MC / BC-U / T Management Center represented as the Gest Center. MC / BC-U / T, the Server MC / BC U, a gateway G, such as the GGSN, an in-between service node S, such as an SGSN, an edge node R such as the BTS and a station mobile MS. The configuration can be initiated both by the operator 10, and in the event that there is an interface to the MC / BC server by said server, 10 '. The operator has to do it manually in contrast to the configuration through the interface to the MC / BC server, which does it automatically. With this operation, the MC / BC-U / T Management Center collects the information on the size of the multicast group with the nodes belonging to it. In the next step the MC / BC-U / T Management Center can do both the multicast group configuration directly, 20 directing the edge nodes directly and indirectly through the highest nodes in the architecture, 20 '. With respect to figure 3 the Management Center MC / BC-U / T sends a message, 20 'to the gateway G, which deals with the establishment of the connection, 30' and 40 'towards the mobile station MS.

Of course there can be more than one T-multicast group in a network.

A preferred embodiment of the invention is given below. She describes the registration procedure.

In case a BTS or Node B is ordered to broadcast-R a T-multicast service in the corresponding geographic area, the BTS or Node B receives the T-multicast address for the U-broadcast service and the QoS required. The MC / BC-U / T Management Center may provide additional information to be used by the registry for the multicast group-T. Due to the fact that each node has information about all corresponding lower-level nodes in the hierarchy, instead of ordering each lower-level node by means of a dedicated unicast message, a general configuration multicast group can be used to direct all lower-level nodes. The BTS or Node B stores the received multicast information and registers itself to the corresponding T-multicast cast tree. This can be done in the event that an IP transport network uses IGMP / MDL and causes a T-multicast cast tree with the BTS or Node B as the leaf of the tree. The log message can be sent both directly to the root of the tree and to nearby nodes, which forward the message to the root.

ES 2 333 703 T3

The following is an embodiment of the registration procedure with respect to Figure 4. Figure 4 shows an example of registration, when a gateway 101 is ordered to establish connections to nodes belonging to a certain geographical area. For this purpose the gateway G sends a request message to the affected nodes using the hierarchical principle 102, 103. To register the edge node to a multicast group, R sends an IGMP message to gateway G 104 after the multicast cast tree for T-multicast has been established from the gateway to edge nodes R, which are the leaves of the tree, 105, 106. The multicast cast tree for Multicast-T can be based for example on the TLMGs described above. In this case after retrieving the IGMP message a TLMG is built from the GGSN, which is an example of a G gateway to the BTS, which are an example for the edge node R. The GGSN can address the BTS directly or it can build a TLMG to the SGSN, which is an example of a serving node S, and instructs the SGSN to build a TLMG for the BTS. In effect, a source-based multicast tree is created between the GGSN and all affected nodes to provide the T-multicast service. It is also possible to have pre-configured TLMGs, which are pre-established with certain QoS parameters.

A preferred embodiment of the invention is given below. She describes the broadcast sharing procedure with respect to Figure 5. Figure 5 includes the same nodes as in Figure 3.

In the first step the MC / BC server sends the broadcast data to the G gateway, 200. The broadcast data is sent through the defined broadcast channels. The gateway G is configured in the way that it knows which broadcast channels correspond to which T-multicast cast tree within the network. For this purpose the gateway G can manage an allocation table to assign the broadcast channels that exist on the interface to the MC / BC server for the multicast channels in a multicast tree that exist on the core network. Gateway G redirects broadcast data from the user layer, such as the application IP layer, to the transport layer, such as the IP transport layer, which is used to multicast the data through a tree Multicast-T casts such as TLMG, 201, 202. The intermediate nodes, S after receiving the multicast data-T both simply forward it to the neighboring nodes as further processing is done for the data, such as other encapsulation. The data is sent using the T-multicast technique, until the edge node, R. In the generic description in case a higher-level node in the PLMN has to T-multicast a service in the corresponding geographical area, the node instructs all lower-level nodes to T-multicast the service. This means in case an SGSN is ordered to multicast-T a service, the SGSN orders the RNCs to multicast-T. Preferably IP multicast is used to distribute the data to the R edge nodes. Edge node R makes a mapping from multicast-T to broadcast-R and broadcasts the data to users.

Additional information can be provided to users in the corresponding geographic area to inform them about the U-broadcast service and the corresponding content. This U-broadcast service information is kept in the MC / BC-U / T servers but would be updated from the MC / BC-U / T management center. This means that the U-broadcast service information can be sent in a default pre-configured BC-U sequence, which is known to all terminals, such as videotext. The distribution of the U-broadcast service information can also be a task of the MC / BC-U server, which informs the end-user terminals about the availability of a service. This could be accomplished by sending availability information and program recall details through an available data transmission service, such as SMS, USSD, WAP, or a Session Announcement Protocol.

The information on the availability of the broadcast service is preferably sent to those nodes, which belong to a certain geographical area. The configuration can be performed both when the network is started and the broadcast service is adapted to the configuration and when the network is configured on demand, which means that when a new broadcast service is supported, a network configuration is performed. . In the latter case it is preferable to use the interface between the broadcast capable server and the broadcast management center.

The solution covered in this invention focuses on the packet switched domain in the GSM or UMTS network. In general, the idea can be applied whenever tunneling is used, such as with GTP, L2TP, IPSec, mobile IP, etc. Therefore, the invention can be applied to any networks with two IP layers, which involves an application IP layer and a transport IP layer. The mechanisms can also be applied in the case where the transport layer is based on another technology that supports multicast transmission such as ATM with multicast enhancements.