WO2012136248A1

WO2012136248A1 - Assessing network user quality of experience based on correlation of signaling events

Info

Publication number: WO2012136248A1
Application number: PCT/EP2011/055264
Authority: WO
Inventors: Petri Kristian SILEN; Jyrki Petteri BERG; Sampo Kristian TORIKKA; Jani-Pekka Virtanen
Original assignee: Nokia Siemens Networks Oy
Priority date: 2011-04-05
Filing date: 2011-04-05
Publication date: 2012-10-11

Abstract

The invention relates to an apparatus comprising at least one processor and at least one memory including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: obtain signaling event information, the signaling event information being gathered in a plurality of networks; determine signaling events from the signaling event information, and choose signaling events for combining from the determined signaling events and combine the chosen signaling events for obtaining information on user experience in the plurality of networks.

Description

Title

ASSESSING NETWORK USER QUALITY OF EXPERIENCE BASED ON CORRELATION OF SIGNALING EVENTS

Field

The invention relates to apparatuses, methods, a system, computer programs, computer program products and computer- readable media.

Background

The following descrip Lion or oacKgrouna art may include insights, discoveries , understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context .

The expectations of end-users regarding the quality of service are becoming higher. The change of customer habits introduces more demands for the availability of services in communications networks .

Brief description

According to an aspect of the present invention, there is provided an apparatus comprising: at least one processor and at least one memory including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: obtain signaling event information, the signaling event information being gathered in a plurality of networks; determine signaling events from the signaling event information, and choose signaling events for combining from the determined signaling events and combine the chosen signaling events for obtaining

information on user experience in the plurality of

networks .

According to yet another aspect of the present invention, there is provided a method comprising: obtaining signaling event information, the signaling event information being gathered in a plurality of networks; determining signaling events from the signaling event information, and choosing signaling events for combining from the determined

signaling events and combine the chosen signaling events for obtaining information on user experience in the plurality of networks.

According to yet another aspect of the present invention, there is provided an apparatus comprising: means for obtaining signaling event information, the signaling event information being gathered in a plurality of networks; means for determining signaling events from the signaling event information, and means for choosing signaling events for combining from the determined signaling events, and combine the chosen signaling events for obtaining

information on user experience in the plurality of

networks .

According to yet another aspect of the present invention, there is provided a computer program embodied on a computer-readable storage medium, the computer program comprising program code for controlling a process to execute a process, the process comprising: obtaining signaling event information, the signaling event

information being gathered in a plurality of networks; determining signaling events from the signaling event information, and choosing signaling events for combining from the determined signaling events and combine the chosen signaling events for obtaining information on user experience in the plurality of networks. List of drawings

Some embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which

Figure 1 illustrates an example of a system;

Figure 2 is a flow chart, and

Figure 3 illustrates an example of an apparatus.

Description of embodiments

The following embodiments are only examples. Although the specification may refer to "an", "one", or "some"

embodiment ( s ) in several locations, this does not

necessarily mean that each such reference is to the same embodiment ( s ) , or that the feature only applies to a single embodiment. Single features of different

embodiments may also be combined to provide other

embodiments .

Embodiments are applicable to any user device, such as a user terminal, relay node, server, node, corresponding component, and/or to any communication system or any combination of different communication systems that support required functionalities. The communication system may be a wireless communication system or a communication system utilizing both fixed networks and wireless

networks. The protocols used, the specifications of communication systems, apparatuses, such as servers and user terminals, especially in wireless communication, develop rapidly. Such development may require extra changes to an embodiment. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, embodiments.

A next generation network (NGN) is a concept of

architectural evolutions in relation to core and access networks of a communication system. One target of the NGN is that one network transports all kinds of information and services, such as voice, data and media by

encapsulating these services into packets in the similar manner as on the Internet. Term "all-IP" is also used to describe this idea. All-IP is aimed to provide a merged data/voice/multimedia network. It should be appreciated that service-related functions are designed to be

independent from underlying transport-related

technologies. One example of suitable technologies to be used in this context is Voice over Internet protocol

(VoIP) .

Quality of Service (QoS) is an important issue in

providing VoIP, multimedia and other corresponding

services. An end-user expects that their connection is not delayed or dropped due to other traffic. A service having a required Quality of Service (QoS) may be achieved by managing latency or delay, delay variation or jitter, bandwidth, and/or packet loss parameters by a network. For example, a long delay may cause a noticeable echo, delay variations may cause strange sound effects and packet loss may cause interruptions in a conversation or in the run of a video clip, etc.

The picture is even more complicated when a network topology and/or node connectivity change in the course of time. One example of such networks is so-called ad-hoc networks. Ad hoc networks comprise a plurality of (mobile) nodes coupled by wireless links forming arbitrary time- varying wireless network topologies. Nodes of an ad hoc wireless network may move randomly and self-organize themselves in an arbitrary fashion.

With reference to Figure 1, we examine an example of a communications system to which embodiments of the

invention may be applied. The exemplary communications system used herein is the Universal Mobile

Telecommunications System (UMTS) radio access network (UTRAN) . It is a radio access network which includes wideband code division multiple access (WCDMA) technology and can also offer real-time circuit and packet switched services. The embodiments are not, however, restricted to the systems given as examples but a person skilled in the art may apply the solution to other communication systems. Figure 1 depicts examples of simplified system

architectures only showing some elements and functional entities, all being logical units, whose implementation may differ from what is shown. The connections shown in Figure 1 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the system typically comprises also other functions and structures than those shown in Figure 1.

The embodiments are not, however, restricted to the system given as an example but a person skilled in the art may apply the solution to other communication systems provided with the necessary properties. Some examples of other options for suitable systems are groupe special mobile or global system for mobile communications (GSM) , time division synchronous code division multiple access (TD- SCDMA) , long term evolution (LTE, the same as E-UTRA) , long term evolution advanced (LTE-Advanced) wireless local area network (WLAN or WiFi) , worldwide interoperability for microwave access (WiMAX) , Bluetooth®, personal

communications services (PCS) , ZigBee®, wideband code division multiple access (WCDMA) , systems using ultra- wideband (UWB) technology, sensor networks, mobile ad-hoc networks (MANETs) and Internet Protocol multimedia

subsystems (IMS) .

Figure 1 is a simplified illustration of a communications system or cooperation of a plurality of communications systems to which embodiments according to the invention are applicable. Figure 1 shows parts of two cellular radio systems which comprise radio network elements 100, 118 into which functionalities of a base station and a radio network controller are integrated. The communications network may include separate base stations and radio network controllers, but in this example the part of the network is depicted as its simplest.

The radio network controller 100 has bi-directional radio links 102 and 104 to user devices 106 and 108 and the radio network controller 118 has bi-directional radio links 120, 122 to user devices 124, 126. The user devices may be fixed, vehicle-mounted or portable. The radio network element includes transceivers, for instance. From the transceivers of the radio network element a connection is provided to an antenna unit that establishes bi^¬ directional radio links to the user devices.

The radio network element 100 is further connected to a core network 110 (CN) and the radio network element 118 is further connected to a core network 116. The counterpart on the CN side can be a media gateway (MGW) or a serving GPRS (General Packet Radio Service) support node (SGSN) , a gateway GPRS support node (GGSN) , where GPRS is an

abbreviation of a general packet radio service, etc. The GPRS Core Network provides mobility management, session management and transport for Internet Protocol packet services in Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) networks .

GPRS Tunneling Protocol (GTP) is an Internet protocol of the GPRS core network. It enables a user device to

maintain Internet connections while moving. It conveys subscriber data from the subscriber's current SGSN to the GGSN which is handling the session.

The communication systems are also able to communicate with other networks, such as the Internet 112.

As to other possible systems, such as the GSM, the network topology may differ from what is depicted in Figure 1. As an example, a counterpart on the CN side in the GSM may be a mobile switching centre (MSC) that is a service delivery node for the GSM (and also for the code division multiple access systems) which is responsible for routing voice calls as well as other services. The MSC sets up and releases end-to-end connections, handles mobility and handovers, etc.

In the example, two communications networks are in

cooperation with each other and operationally linked for this reason by a correlation server (CS) 114. The

correlation server may be a stand-alone network element or it may operationally or even physically be integrated in one of the core networks serving the communications networks which in this case may be thought as some kind of sub-networks in the end-user's point of view, etc. Arrow 128 depicts that a correlation server may be coupled to an external network (not shown) . The external network may be any kind of communication network.

In the following, some embodiments are disclosed in further details in relation to Figure 2. The embodiment of Figure 2 is usually related to a server or host that may operate as a correlation server.

The expectations of end-users regarding the quality of service are becoming higher. The change of customer habits introduces more demands for the availability of services in communications networks. In order to meet these

expectations, operators need tools for evaluating or verifying the quality of service and/or user experience each end user is experiencing. One challenge is to obtain reliable real-time information about a user experience when the service used deploys multiple networks, such as a radio network and core network. In such a case, typically, information needs to be searched from multiple data bases and sources which typically results in an uncorrelated real-time view of a user experience. Unfortunately, this, in many cases, also needs manual work for matching data records together. Additionally, it is possible that some information, which is available in a core network, is not available in a radio network leading to insufficient data for end user level troubleshooting.

An embodiment of the invention relates to correlation of end-user experiences in computer and/or communication networks. One target is to enrich information on end-user experiences in a centralized manner for obtaining improved views of them. The processing of information may be carried out in real-time. Term "real-time" may in this application refer to a processing delay which is

adequately unnoticeable in an end-user's point of view. An acceptable delay may vary according to the service at issue. Typical delay-critical services are voice calls, conventional videoconferences and telepresence. It is also possible that protocols used determine limits to

acceptable end-to-end or other kinds of delays in which case these limits may be applied.

The embodiment starts in block 200. The embodiment is especially suitable to be carried out by a correlation server or a corresponding element.

In block 202, signaling event information is

obtained. The signaling event information is gathered in a plurality of networks.

Signaling event information may be typical signaling event information (SEI) used in telecommunication networks collected by network elements (NEs) , signaling transfer points (STPs) and/or signaling link probes (SLPs) , and conveyed to a correlation server (CS) typically in real^¬ time .

According to one definition, a signaling event (SE) takes place when a network element or an STP

sends/transmits/receives/forwards a signaling message (SM) , or when an SLP captures a signaling message in a signaling link it monitors. A signaling message may be according to any signaling protocol used in communication networks (signaling system 7 (SS7) that is a telephone signaling protocol or Internet Protocol (IP), for

example) .

Signaling event information (SEI) is usually information with regard to a signaling event. SEI may be any piece of information or a full information element (IE) inside a signaling message. SEI may for example be a subscriber identity, such as a mobile station international ISDN

(integrated services digital network number) (MSISDN) or international mobile subscriber identity (IMSI), network entity, such as a location area code (LAC) or a cell Id (CID) , or a cause code specified by 3rd Generation

partnership project (3GPP) .

Typically, an end-user is served by utilizing cooperation of a plurality of networks, such as a wireless network and core network. In this application term "network" may mean one network in the sense that it operates according to one radio or other protocol, a combination of several networks established for providing services to users, such as a network which comprises a "basic" network and one or more ad hoc networks operating under the control of the "basic" network, a combination of networks operating under the control of different operators with negotiated rules for cooperation control, etc. The interpretation of the term "network" is emerging along with the progress of the information society and thus it has to be interpreted broadly both in the real-world and as an abstract concept. One example of a possible arrangement for the cooperation of a plurality networks is shown in Figure 1. A

correlation server is shown as an option by reference number 114.

In block 204, signaling events are determined from the signaling event information. A correlation server may store signaling information (in real-time) into a database and/or internal data structure for processing.

Signaling and thus signaling events are in relation to actions needed for providing services to users. Signaling is needed for establishing a call, establishing a tunnel for data transfer, providing security and encryption, carrying out handovers, obtaining location information, etc. Communications networks are typically quite

complicated from this viewpoint.

Each event concerning signaling is called a signaling event. Usually, several signaling events which may use different protocols, take place on different layers and between different network elements are required for providing a service, such as a call, for an end-user. For possible fault detection, it is common that many signaling events involved in the faulty service must be searched for. Thus, a need for determining signaling events from signaling event information exists. Typically, signaling event information is recognized and then unpacked for this determination .

As put forward above, according to one definition, a signaling event (SE) takes place when a network element or a STP sends/transmits/receives/forwards a signaling message (SM) , or when an SLP captures a signaling message in a signaling link it monitors. A signaling message may be according to any signaling protocol used in

communication networks (signaling system 7 (SS7) that is a telephone signaling protocol or Internet Protocol (IP) for example) .

In block 206, the signaling events are chosen for combining and the chosen signaling events are combined for obtaining information on user experience in the plurality of networks. A correlation server may use correlation as means for choosing suitable ones from multiple signaling events (SE) according to defined correlation rules (CRs) . A

correlation rule may be defined as one or more pieces of signaling event information that need to match between two different signaling events. Further, the correlation server may create combined information (CI) from signaling events that have been correlated in real-time according to information combination rules (ICRs) . ICR may be defined as signaling events that have been correlated. CI is thus typically a subset of all SEIs from correlated SEs.

In an exemplifying case, a call is controlled in a mobile network by a switch, such as a mobile switching server (MSS) , and the call is conveyed as a VoIP-transmission between media gateway (MGW) elements in an Internet

Protocol ( IP) -network . In this case, the MSS is

responsible for establishing and finishing the call as well as collecting location information and the MGW of the network, where the call is established, transfers voice and/or sound into a suitable format for the IP-network and takes care of routing. The quality of the call may only be evaluated by analyzing the quality of IP-traffic via the MGW elements by using one or more methods usually used for this purpose. The switch (MSS) cannot provide necessary parameters, since it does not see IP-traffic.

Thus by choosing and combining signaling events, it is possible to enhance the observation of the quality of service. In the exemplary case, information on

establishing the call and user' s location is combined with information on the quality of service obtained in reality. Enriched user information may be accomplished in such a manner that peaces of information (which typically are in the form of reports or records) are combined, typically in real-time, and stored in a database. Thus an end-user report comprises these pieces of information instead of a plurality of separate reports that may even be stored in different databases in different networks.

For obtaining useful and enriching combination of

information, it is relevant to choose right pieces of information for combining. Thus pieces of information may be correlated or chosen by using an appropriate criterion, usually a common denominator. In the exemplifying case, the common denominator may be subscriber identification or a global call reference number, for example. In this application, the criterion is called a correlation rule. If put in a simplified manner, it may be said that first the pieces of information are correlated to find suitable ones from the information space, and then combined in a desired way to produce the kind of end-user reports which are useful in evaluating end-user experience.

A correlation rule or criterion (or rules or criteria) may, for example, be at least one of the following: one or more parameters identifying the end-user, one or more parameters indentifying elements used for providing the service and one or more parameters identifying the service and/or service status in question.

It should be understood that information obtained may also be used for statistical analysis, if collected within a longer period of time and not only for real-time use.

Therefore is it possible for operators to identify

possible bottlenecks in their network.

The correlation server may convey combined information in real-time to one or more external systems, such as to one or more external network being responsible of network control functionalities in the networks the signaling event information is gathered from.

The end-user experience information may thus be enriched in a centralized manner. Some examples of signaling event information to be enriched are control plane experience information of a mobile switching center (MSC) server and user plane experience information of a multimedia gateway. Another example is enriching radio network control (RNC) data of a wide band code division multiple access (WCDMA) radio network with a mobile type international mobile equipment identity (IMEI) information, which is available to an MSC server but not to an RNC.

The embodiment ends in block 208. The embodiment is repeatable in many ways. One example is shown by arrow 210 in Figure 2.

The steps/points, signaling messages and related functions described above in Figure 2 are in no absolute

chronological order, and some of the steps/points may be performed simultaneously or in an order differing from the given one. Other functions can also be executed between the steps/points or within the steps/points and other signaling messages sent between the illustrated messages. Some of the steps/points or part of the steps/points can also be left out or replaced by a corresponding step/point or part of the step/point.

It should be understood that conveying, transmitting and/or receiving may herein mean preparing a data

conveyance, transmission and/or reception, preparing a message to be conveyed, transmitted and/or received, or physical transmission and/or reception itself, etc on a case by case basis.

An embodiment provides an apparatus which may be any node, host, server, user device or any other suitable apparatus capable to carry our processes described above in relation to Figure 2.

Figure 3 illustrates a simplified block diagram of an apparatus according to an embodiment especially suitable for network control.

As an example of an apparatus according to an embodiment, it is shown an apparatus 300, such as a node device, host or server, including facilities in a control unit 304 (including one or more processors, for example) to carry out functions of embodiments, such as choose and combine signaling events for obtaining information on user experience in the plurality of networks. This is depicted in Figure 3.

Another example of an apparatus 300 may include at least one processor 304 and at least one memory 302 including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: obtain

signaling event information, the signaling event

information being gathered in a plurality of networks; determine signaling events from the signaling event information, and choose signaling events for combining from the determined signaling events, and combine the chosen signaling events for obtaining information on user experience in the plurality of networks.

Yet another example of an apparatus comprises means 304 for obtaining signalling event information, the signalling event information being gathered in a plurality of networks; means 304 for determining signaling events from the signaling event information, and means 304 for choosing signaling events for combining from the

determined signalling events, and combine the chosen signaling events for obtaining information on user experience in the plurality of networks.

Yet another example of an apparatus comprises an obtainer configured to obtain signaling event information, the signaling event information being gathered in a plurality of networks; a determining unit configured to determining signaling events from the signaling event information, and a chooser configured to choose signaling events for combining from the determined signaling events and combine the chosen signaling events for obtaining information on user experience in the plurality of networks. Although the apparatuses have been depicted as one entity in Figure 3, different modules and memory may be

implemented in one or more physical or logical entities. An apparatus may in general include at least one

processor, controller or a unit designed for carrying out control functions operably coupled to at least one memory unit and to various interfaces. Further, the memory units may include volatile and/or non-volatile memory. The memory unit may store computer program code and/or

operating systems, information, data, content or the like for the processor to perform operations according to embodiments. Each of the memory units may be a random access memory, hard drive, etc. The memory units may be at least partly removable and/or detachably operationally coupled to the apparatus. The memory may be of any type suitable for the current technical environment and it may be implemented using any suitable data storage technology, such as semiconductor-based technology, flash memory, magnetic and/or optical memory devices. The memory may be fixed or removable.

The apparatus may be a software application, or a module, or a unit configured as arithmetic operation, or as a program (including an added or updated software routine) , executed by an operation processor. Programs, also called program products or computer programs, including software routines, applets and macros, can be stored in any

apparatus-readable data storage medium and they include program instructions to perform particular tasks. Computer programs may be coded by a programming language, which may be a high-level programming language, such as objective-C, C, C++, Java, etc., or a low-level programming language, such as a machine language, or an assembler.

Modifications and configurations required for implementing functionality of an embodiment may be performed as

routines, which may be implemented as added or updated software routines, application circuits (ASIC) and/or programmable circuits. Further, software routines may be downloaded into an apparatus. The apparatus, such as a node device, or a corresponding component, may be

configured as a computer or a microprocessor, such as single-chip computer element, or as a chipset, including at least a memory for providing storage capacity used for arithmetic operation and an operation processor for executing the arithmetic operation.

Embodiments provide computer programs embodied on a distribution medium, comprising program instructions which, when loaded into electronic apparatuses, constitute the apparatuses as explained above.

Other embodiments provide computer programs embodied on a computer readable medium, configured to control a

processor to perform embodiments of the methods described above .

The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a number of computers .

The techniques described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices) , firmware (one or more devices) , software (one or more modules) , or combinations thereof. For a hardware implementation, the apparatus may be implemented within one or more application specific integrated circuits (ASICs) , digital signal processors (DSPs) , digital signal processing devices (DSPDs) , programmable logic devices (PLDs) , field programmable gate arrays (FPGAs) , processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the

implementation can be carried out through modules of at least one chip set (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case it can be communicatively coupled to the processor via various means, as is known in the art.

Additionally, the components of systems described herein may be rearranged and/or complimented by additional components in order to facilitate achieving the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art .

It will be obvious to a person skilled in the art that, as technology advances, the inventive concept may be

implemented in various ways. The invention and its

embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. An apparatus comprising:

at least one processor and at least one memory including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

obtain signaling event information, the signaling event information being gathered in a plurality of

networks ;

determine signaling events from the signaling event information, and

choose signaling events for combining from the determined signaling events and combine the chosen

signaling events for obtaining information on user

experience in the plurality of networks.

2. The apparatus of claim 1, wherein the signaling event information is collected by network elements (NEs) , signaling transfer points (STPs) and/or signaling link probes (SLPs) , and conveyed to a correlation server (CS) .

3. The apparatus of claim 1 or 2, further configured to :

store signaling information into a database and/or internal data structure for processing.

4. The apparatus of any preceding claim, further

configured to:

use correlation for choosing suitable ones from multiple signaling events (SE) according to a predefined

correlation rule (CR) .

5. The apparatus of claim 4, wherein the predefined correlation rule is defined as one or more pieces of signaling event information that need to match between two different signaling events.

6. The apparatus of any preceding claim, wherein the predefined correlation rule is at least one of the

following: one or more parameters identifying the end- user, one or more parameters identifying elements used for providing the service and one or more parameters

identifying the service and/or service status in question.

7. The apparatus of any preceding claim, the apparatus comprising a server, host or node.

8. A computer program comprising program instructions which, when loaded into the apparatus, constitute the modules of any preceding claim 1 to 6.

9. A method comprising:

obtaining signaling event information, the signaling event information being gathered in a plurality of networks;

determining signaling events from the signaling event information, and

choosing signaling events for combining from the

determined signaling events and combine the chosen

signaling events for obtaining information on user

experience in the plurality of networks.

10. The method of claim 9, wherein the signaling event information is collected by network elements (NEs) , signaling transfer points (STPs) and/or signaling link probes (SLPs) , and conveyed to a correlation server (CS) .

11. The method of claim 9 or 10, further comprising:

storing signaling information into a database and/or internal data structure for processing.

12. The method of any preceding claim, further comprising: using correlation for choosing suitable ones from multiple signaling events (SE) according to a predefined

correlation rule (CR) .

13. The method of claim 12, wherein the predefined

correlation rule is defined as one or more pieces of signaling event information that need to match between two different signaling events.

14. The method of any preceding claim, wherein the

predefined correlation rule is at least one of the

identifying the service and/or service status in question.

15. An apparatus comprising means for carrying out the method according to any one of claims 9 to 14.

16. A computer program embodied on a computer-readable storage medium, the computer program comprising program code for controlling a process to execute a process, the process comprising:

obtaining signaling event information, the signaling event information being gathered in a plurality of

networks ;

determining signaling events from the signaling event information, and

choosing signaling events for combining from the

determined signaling events and combine the chosen

signaling events for obtaining information on user

experience in the plurality of networks.

17. The computer program of claim 16, wherein the

signaling event information is collected by network elements (NEs) , signaling transfer points (STPs) and/or signaling link probes (SLPs) , and conveyed to a

correlation server (CS) .

18. The computer program of claim 16 or 17, the process further comprising:

19. The computer program of any preceding claim, the process further comprising:

using correlation for choosing suitable ones from multiple signaling events (SE) according to a predefined

correlation rule (CR) .

20. The computer program of claim 19, wherein the

predefined correlation rule is defined as one or more pieces of signaling event information that need to match between two different signaling events.

21. The computer program of any preceding claim, wherein the predefined correlation rule is at least one of the following: one or more parameters identifying the end- user, one or more parameters identifying elements used for providing the service and one or more parameters

identifying the service and/or service status in question.