FI108980B - Transport mechanism for MAP - Google Patents

Abstract

A method of transmitting signalling information between two co-located signalling points of a Public Land Mobile Network. Signalling messages are formulated according to the Mobile Application Part (MAP) protocol and are passed to an adaptation layer which determines whether or not an IP address is available for the destination signalling point. If an IP address is available, The MAP messages are transmitted between the two signalling points using a packet switched data network, otherwise an SS7 network is used to transport the messages.

Description

108980

Transport mechanism for mobile part Transportmekanism för MAP

Field of the Invention

The invention relates to a transport application for a mobile application part for use in a public land mobile network.

Background of the Invention

Existing public mobile communication networks (PLMNs) carry signaling information relating, for example, to call set-up procedures, call management and termination, generally between signaling points by a transport mechanism based on Signaling System No.7 (SS7). SS7 is a commonly used transport protocol with multiple protocol layers.

Information exchange between mobile switching centers (MSCs), location registers; . (HLRs, Home Location Registers), and visited the visitor location registers * ·· (VLRs, Visitor Location Registers) using stan- | · ·· Messages defined by the Mobile Application Part Protocol (MAP) which are carried by the SS7 transport mechanism. More specifically, the SS7 layers involved in transporting MAP messages are: • · Message Transfer Part (MTP), ···, which inter alia provides message separation, error detection and correction, as well as a connection to a physical data channel; a Signaling Control Unit (SCCP) responsible for controlling signaling connections on the SS7 network as well as routing between signaling points; and an Event Processing Unit (TCAP). Transaction Capabilities Application Part), which facilitates the use of Intelligent Network Services (IN) by providing information exchange between signaling points using a offline SCCP service.

1 The complexity of the conventional transport mechanism is easily discernible, but such complexity is necessary to ensure correct routing and error-free signaling data; transmission between the plurality of PLMN signaling points.

Summary of the Invention

The inventors have found that the complex transport mechanism of SS7 is not necessary for the transmission of MAP messages between PLMN co-located signaling points, i.e., points located in close proximity to one another. Therefore, it is possible! The list uses a "lightweight" transport mechanism, which reduces or avoids the coding and decoding needs inherent in the SS7 transport mechanism.

According to a first aspect of the invention, there is provided a method of transferring signaling information between two signaling points of a public mobile network, the signaling points being in the same location, the method comprising; shaping said signaling information into words according to a cellular network protocol (MAP) protocol; and 3,108,980 messages between two signaling points using a packet switched data network.

Since the signaling points to which the method of the invention is applied are located in the same location, it is possible to connect the two signaling points using a direct connection.

Embodiments of the invention eliminate the need to handle the sea carrier information using TCAP and SCCP when the information is to be transferred between signaling points located in the same location.

Preferably, the above method is used in the network after the signaling point wishing to send the MAP message has determined whether or not the message destination is located at the same location. In the case where the destination signaling point is not located in the same location, a network other than said packet switched data network may be used to carry the message. One such alternative network is the SS7 network.

Preferably, the PLMN signaling points interconnected by said packet switched data network to one another have two or more of the following: a mobile communication center (MSC), a gateway (GMSC, English Gateway Mobile

Switching Center), Home Location Register (HLR), or Visitor \ * * 'Register (VLR). Signaling points may also include one or more intelligent network nodes (IN nodes).

Preferably, the packet switched data network is an IP network in which the MAP is located on top of the IP layers (including the IP ··· protocol layer and the TCP and / or UDP layer) from each of the signaling points located at the same location. Where 4108980 signaling points in the same location have access to the SS7 network, the signaling points' MAP can also be located on top of the SS7 protocol layers. More preferably, an adaptation layer is provided between the MAP and the IP and SS7 layers, as the adaptation layer responds to the initiation of the MAP dialog. whether the address of the dialog destination (e.g.

whether or not it is a signaling point at the same location. If the destination address of the dialog (for example, the general address) matches the signaling point at the same location, the matching layer specifies the IP address corresponding to the destination address.

According to another aspect of the invention, there is provided a device for transmitting signaling information between two signaling points in a public mobile network, the signaling points being in the same location, the device comprising: first signal processing means for shaping said signaling information into mobile communication protocol (MAP) protocol; second signal processing means for shaping the MAP messages according to the packet switched data transport mechanism; and: "transmission means for transmitting shaped packet switched messages between • two signaling points over a packet switched network.

According to a third aspect of the invention, there is provided a signaling point ,, within a public mobile network (PLMN), the signaling point comprising: first signal processing means for shaping said signaling information into cellular communications protocol (MAP) protocol; 108980 5! other signal processing means for formatting the MAP messages i | a packet switched data transport mechanism; and transmission means for transmitting the formatted packet switched messages to another signaling point located at the same location over the packet switched network.

The signaling point may also serve as a signaling transfer point for messages received from other location signaling points, whereby the signaling transfer point transmits MAP messages to the same location signaling point via a packet switched network.

Preferably, the signaling point comprises means for determining whether or not the signaling point destined for the MAP message is located in the same location and, if so, for transmitting the MAP messages to said other signal processing means and, if not, for transmitting the MAP messages to the SS7 transport mechanism. manages the transmission of messages over the SS7 network.

BRIEF DESCRIPTION OF THE DRAWINGS In order to make the invention more comprehensible and to illustrate * (not how to implement it, reference will now be made to the accompanying drawings, in which: i »· •» * in the figure 1 schematically illustrates a portion of a public mobile network, FIG. 2 illustrates a transport mechanism connection stack implemented at certain '·' signaling points of the PLMN of FIG. 1, and i * t * »i * 6 108980 FIG. 3 is a flowchart illustrating a method for transmitting 1 between the signaling points of the PLMN of FIG.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS I FIG. 1 is a schematic illustration of a public mobile communication network (PLMN) comprising two gateways (GMSCs) 1, 2 providing an interface to a PLMN and a Public Switched Telephone (PSTN). Network) 3. The GMSCs 1, 2 "represent" the PLMN from the point of view of the PSTN 3, and signaling traffic between them is carried out using the ISDN User Part Protocol (ISUP). GMSCs may also provide interfaces between PLMNs and other networks, although this is not shown in Figure 1.

Within the PLMN, signaling information must be communicated between the network signaling points for call setup, call management and termination purposes. Figure 1 shows a plurality of signaling points within a PLMN, including: GMSCs 1, 2; mobile switching centers (MSCs) 4, 5, which: "are responsible for routing calls within the PLMN; guest location registers (VLRs) 6, 7, which maintain information for each associated MSC. and the location registers (HLRs) 8, 9, which maintain permanent information about PLMN subscribers along with dynamic information about the current location of those subscribers. These signaling points are in close proximity to each other ('d', i.e., ' are "co-located". In some circumstances, signaling points in the same location may be in the same room.

7 108980

Signaling information is transmitted between the different signaling points of the PLMN using the mobile station (MAP) interface protocol. MAP messages are traditionally carried using the SS7 transport mechanism. This mechanism is not explained in detail here (for example, reference should be made to "Understanding Telecommunications", Volumes 1 & 2, Studentlitterat-tur, Lund, Sweden, ISBN 91-44-00214-9), although Figure 1 illustrates an existing SS7 network where SS7 signaling channels (indicated by dashed lines) can be routed through a Signaling Transfer Point (STP) 10. The SS7 transport mechanism is also used for transmitting ISUP signaling messages between GMSCs 1, 2 and PSTN 3.

In Figure 1, solid lines indicate Ethernet connections between signaling points. These Ethernet connections are used to transport the IP datagrams that encapsulate the MAP messages, providing an alternative to the SS7 transport mechanism described in the previous paragraph. Note that only direct Ethernet (point-to-point) connections are available between signaling points, so there is no need for a router on the IP network.

! ! * Figure 2 shows the protocol implemented at each signaling point in the PLMN. The MAP 11 is located on the so-called "adaptation layer" 12, which in turn is located on two separate protocol stacks. The first of these stacks, 13, gives the traditional SS7 · ·% 1 »; ; one, while the other, 14, provides the IP transport mechanism. For MAP 11, layer 12 behaves exactly like TCAP, so no changes to MAP 11 are needed.

t s * »*» »8 108980 The start of the MAP dialog begins by passing a dialog request message from the MAP 11 to the adaptation layer 12. The adaptation layer uses the user ID in the dialog request message to determine the associated Subsystem Number (SSN). Unless the SSN indicates that the user is an HLR, VLR, or MSC, the dialog is assigned for SS7 and standard SS7 procedures are used (i.e., protocol stack 13).

On the other hand, if the SSN indicates that the user is an HLR, VLR or MSC, the adaptation layer 12 checks the called address, i.e. the Global Title (GT). Each MSC / VLR, GMSC, and HLR in the same location as the calling signaling point is associated with a set of general addresses. These sets are pre-stored in the address table to which the access layer 12 has access. The address table contains a description between the generic address sequence and the IP address. If the check determines that the called universal address is not in any of the stored universal address sets, the dialog is again transported via SS7. However, if the check confirms that the called universal address is a member of the stored universal address set, the adaptation layer sends a request acceptance message back to MAP 11, provided that the TCP / IP link to that address is active. In the event that the identified · · I, '·· link is not active, the dialog is again transported via SS7 ·, ·. *. Subsequent messages related to the same dialog are transported, · · · via IP or SS7, depending on the initial checks performed by the adaptation layer.

) k · ... * Requires a check of the address called by the MAP dialog request message::: To limit the CPU load, the number of addresses that can be stored in the address table is relatively limited, ··. ·. there is a limited number of co-located signaling 1Q8980 9 nodes capable of utilizing a light IP transport mechanism. A suitable number of signaling points may be six or less.

Fig. 3 is a flowchart illustrating the processing steps to be performed at the signaling point following the initiation of the MAP dialog. These steps are typically performed by a suitably programmed computer, or one or more Digital Signal Processors (DSPs), although other suitable implementations can easily be seen.

One skilled in the art will recognize that various modifications may be made to the embodiment described above without departing from the scope of the invention. For example, instead of using TCP routing over IP, a simpler routing protocol, e.g., point-to-point protocol (PPP), may be used. When further modifying the invention, the invention may be used from a calling signaling point, which is not in the same location as the receiving signaling point, at the signaling transfer point | for forwarding received MAP messages to a destination token. to a signal point located in the same location as the signal transfer point • »·: · ... In this case, the Signal Transfer: · .. header checks if the destination address of the received MAP messages is included in the address table described above and, if so, determines the associated IP address.

• · ·

Claims (10)

10 108980 A method for transmitting signaling information between two signaling points in a public mobile network, which are located at the same location (are colocated), the method comprising; shaping said signaling information into a protocol according to the Mobile Application Part (MAP); and transmitting the MAP messages between the two signaling points over the physical connection using the packet switched network protocol. The method of claim 1, comprising the step of determining at the signaling point that wants to send the MAP message whether the message destination is at the same location signaling point and if the destination signaling point is not at the same location, the message is transported by a network other than said packet switching . through a physical connection using its network protocol: · ... The method of claim 1 or 2, wherein the PLMN signaling points interconnected by a physical connection using said packet switched network protocol V · 'include two or more of the following: a mobile services switching center (MSC), a gateway switching center (GMSC). ), the Home Location Register (HLR), and the Visitors Register (VLR). The method of any one of the preceding claims, wherein the packet switched network protocol is an IP network protocol and the MAP is located on top of the IP layers at each signaling point located in the same location. The method of claim 4, wherein the co-located signaling points have access to the SS7 network and the signaling points MAP are located on top of the SS7 connection protocol layers. The method of claim 5, wherein an adaptation layer is provided between the MAP and the IP and SS7 layers, the adaptation layer responsive to initiating the MAP dialog by determining whether or not the dialog destination address corresponds to a signaling point located at the same location and location signaling point, the adaptation layer specifies the IP address corresponding to the destination address. A device for transmitting signaling information between two signaling points in a public mobile network, denoted by. the reference points are located in the same place, the device being understood; ; first signal processing means for the said signal · '/ ·;' formatting the information into messages according to the mobile communication part (MAP) protocol; Second signal processing means for shaping the MAP messages according to the packet switched data transport mechanism; and •: Means for transmitting formatted packet switched messages between two signaling points over a physical: • packet switched network connection. A signaling point inside a public mobile communication network (PLMN), the signaling point comprising: 12 108980 first signal processing means for shaping said signaling information into messages according to the protocol of the mobile station (MAP); second signal processing means for shaping the MAP messages according to the packet switched data transport mechanism; and transmission means for transmitting the formatted packet switched messages to another signaling point located at the same location via a physical connection using the packet switched network protocol. The signaling point of claim 8, wherein the signaling point serves as a signaling transfer point for messages received from other location signaling points, wherein the signaling transfer point transmits MAP messages to the same location signaling point through a physical connection using a packet switched network protocol. . A signaling point according to claim 8 or 9,; · .. whereby the signaling point comprises means for determining whether si-. whether or not the signaling destination at which the MAP message is located is located at the same location and, if located, transmits the MAP messages to: .V to said other signal processing means and, if not present; network. »» * S I t 13 108980