Call handling in a communication network

ES 2 227 261 T3

DESCRIPTION

Call handling in a communications network.

Background of the invention

Intelligent network (IN) services have become common in modern telephone systems. Such IN services notably improve the functionality of telephone systems beyond the classical concept of simply connecting a terminal that originates a call with a terminal that is the destination of the same. The "intelligence" of an intelligent network consists of the capacity it has to identify certain calls as associated with certain services, such as sending the call, waiting in line for the call, holding the call, etc. The basic concept of intelligent network services is well known in the art and need not be described in further detail here.

One way of providing an IN technique that is flexible in not being fixedly associated with a telephone standard is to provide a call handling device that is arranged to receive network calls and apply routing information to such calls, whose call handling device also checks whether an IN service is to be invoked for a call and, if it is decided to do so, sends appropriate signals to an intelligent network service processing device which will then perform processing to provide the intelligent network service. The fact of providing IN services is especially popular in mobile phone systems and, since competition in the mobile phone field is tough, mobile phone operators want a competitive advantage over other operators offering their own services, which they are not standardized. For mobile phone systems, the known technique of "Custom Applications for Mobile Network Enhanced Logic" (CAMEL) is an example of a standard way of offering IN techniques for mobile networks. CAMEL technology is designed to be used with GSM (Global System for Mobile Communications) or with UMTS (Universal Mobile Telephony Standard).

Fig. 3 shows a basic arrangement of a system for handling calls according to CAMEL. A GSM network 30 contains a headend mobile switching center (GMSC) 10. The network 30 could also be a UMTS network. Reference number 100 indicates a call entering GMSC 10, such that routing information can be applied to said call. In order to do this, the GMSC 10 interrogates the home location register (HLR) 11, which stores information related to call destination information contained in a call that is being routed. Namely, the home location recorder 11 contains information associated with a given subscriber, and a call being routed contains information related to a given subscriber. Typically this will be the directory number assigned to that subscriber. The GMSC 10 will then request routing information associated with said directory number by sending an appropriate signal 101 to the HLR 11. In GSM, such a signal is also known as a MAP message for sending routing information (SRI). Then, the HLR 11 sends back appropriate routing information with a signal 102. This routing information can be a simple roaming number, that is, a number that identifies the mobile switching center (MSC) currently serving the identified mobile subscriber. On the other hand, if an appropriate IN identifier is activated for the given subscriber, then the HLR 11 will provide the GMSC 10 with IN invocation information.

If no IN invocation information is contained in signal 102, then normal routing information (for example, roaming number) is applied to the call and said call is put back into the network, which it is indicated by arrow 107. It can be seen that solid arrows represent content and signage, while dashed arrows only represent signage in Fig. 3.

If IN invocation information is passed to the GMSC 10, then the GMSC 10 routes the call to an entity called gsmSSF (gsm service switching function) 20. In the example of Fig. 3, the GMSC 10 and the gsmSSF 20 are contained in a node 200 of network 30. The gsmSSF 20 then requests information from the so-called gsmSCF (gsm service control function) 21. The gsmSCF 21 instructs the gsmSSF on how to handle the call, and the appropriate IN service is executed. This is indicated by arrows 104 and 105. The gsmSSF 20 then executes the instructions which, for example, may consist of routing the call back to the GMSC, which in turn routes it back to the network, which is indicated using arrows 106 and 107. Of course, this is just an example, as there are a multitude of IN services. In other words, it would also be possible that the gsmSSF 20 could put the call on hold while an outgoing call is initiated for a different subscriber, in order to set up a meeting or conference.

A general problem with IN technology is the additional load imposed on the network when all IN subscriber calls have to be routed to the separate gsmSSF functional entity 20 and an additional procedure called IN activation is needed. IN activation refers to the dialogue between gsmSSF 20 and gsmSCF 21. According to capacity calculations made on a default traffic model, an average increase in the IN invocation load for a call can be very considerable.

The second phase of the CAMEL standard (CAMEL ph2) addresses this problem by introducing a method known as conditional activation. To initiate calls, this method allows the gsmSSF 20 to check certain call conditions, such as the dialed number, basic service code, or call type, prior to IN activation. To terminate calls, this method allows the HLR 11 to check the basic service code before returning the IN data to the GMSC 10. In other words, it is possible to invoke IN depending on the type of call. An example of this could be voice calls being sent, but not fax calls being sent.

Although conditional activation reduces the load on the network, the desire for further load reduction still persists. Can be seen

ES 2 227 261 T3 that this desire is not only related to the specific example shown in Fig. 3, but is related to any system that uses a device for handling calls (consisting of the GMSC 10 and the HLR 11 in the example of Fig. 3) and an intelligent device for the treatment of the network service (consisting of the gsmSSF 20 and the gsmSCF 21 in the example of Fig. 3), where the call handling device is arranged to determine the routing information and to perform an IN invocation under certain conditions.

Object of the invention

The object of the invention is to provide an improved call handling device, an improved call handling system and an improved IN invocation method in a call handling device.

Summary of the invention

This object is solved by a device for handling calls according to claim 1, a system for handling calls according to claim 13 and a method for controlling the invocation of an intelligent network service in a device for the call handling according to claim 16. Advantageous embodiments are described in the dependent claims.

According to the present invention, the decision routine of the call handling device, which makes a decision as to whether an intelligent network service is to be invoked, not only has the ability to check whether a call identifier is active in the stored information. intelligent network in relation to a given call destination, for example in relation to a specific subscriber, but also has additional capacity. This additional capacity comes into play if a call that is being processed is a call that has to be routed to a mobile station, that is, a call that ends in a mobile, and if in the stored information that is used to answer the call an intelligent network identifier is active. Namely, the further determination comprises the step of comparing a stored comparison value of a mobile station condition parameter associated with a corresponding condition of the mobile station to which the call being attended is to be routed, with a current value. of the parameter of the mobile station condition, when the decision related to the invocation of an intelligent network service depends on the result of the comparison.

In other words, the call handling device is capable of making the decision regarding the invocation of an IN service depending on a condition of the mobile station to which the call is to be routed. The condition of the mobile station used for the comparison may be an operational condition or a circumstantial condition (a condition related to the circumstances of the mobile station). An example of an operating condition is the state of the mobile station, which can be described in terms of connect / disconnect state, busy state, or by a certain operating mode. Examples of circumstantial conditions are the situation or the time (dynamic data). The situation can be identified by one or more of a plurality of indicators, such as a country indicator, a network indicator, or a cell indicator. The time can be identified by a date indicator or a clock indicator.

Therefore, in contrast to the prior art, which only provides the possibility of conditional activation with respect to the characteristics of the call being answered, the present invention proposes a conditional activation based on one or more conditions of the mobile station to which it is being answered. that a call is being routed. This offers numerous advantages. For example, there are so-called prepaid subscribers, which means that a subscriber pays in advance for his subscription and the costs of using the network are progressively deducted from the amount previously paid, for example, in the form of a descending record in a SIM card (subscriber identity module) in the mobile station itself. According to the existing technology, all calls to said prepaid subscribers have to be routed to the device for the treatment of the intelligent network service (that is, the gsmSSF in the case of GSM). This constitutes a problem for such network operators, who only want to bill the sending branch of the roaming call when roaming outside the country, as they would like to avoid unnecessary IN activation for calls to prepaid subscribers when they Prepaid subscribers remain on their home PLMN (public land mobile network). According to the present invention, this problem can be solved by practicing the invention in such a way that the condition of the mobile station for which a comparison is carried out is the situation. More specifically, in the above-mentioned example, the condition parameter for which the comparison can be performed may be the network identifier stored together with the subscriber information in the registrar that stores the subscriber information, such as the HLR in the GSM case. Assuming that approximately 90% of calls to prepaid subscribers are received when these subscribers are in their home PLMN, this means that a load reduction of 90% of the additional load generated by IN invocations can be achieved in the as regards such prepaid subscribers, relative to known technology.

Another example where the invention can be advantageously applied is the case of an IN service where the destination of the call is changed based on the status of the called party, such as busy or not reachable, and on the status of idle the call would always be routed normally. In current technology all subscriber calls with such service must be routed to the intelligent network service processing device. Thanks to the application of the present invention, it is possible to invoke not only the IN service when this service proves necessary, for example when the mobile station is busy or not accessible. If the mobile station is idle, then the call is routed normally, without invoking IN. Due to the fact that, on average, the typical mobile terminal will be idle most of the time, such an embodiment of the present invention also considerably reduces the burden due to IN invocations.

Brief description of the drawings

The present invention will be explained in greater detail in connection with preferred embodiments thereof.

ES 2 227 261 T3 mo, which refer to the attached drawings, in which:

Fig. 1 shows a flow chart explaining a basic embodiment of the method of the present invention;

Fig. 2 illustrates a block diagram depicting a preferred embodiment of the call handling system of the present invention; and Fig. 3 shows a block diagram representing a call handling system according to GSM technology, to which the present invention can be applied.

Detailed description of preferred embodiments

Fig. 2 shows a preferred embodiment of a call handling system according to the present invention. A call handling device 1 receives calls 100 and determines routing information for these calls. Reference number 3 represents a communication network between mobiles. Device 1 for handling calls is, for example, part of the network

3. On the other hand, an intelligent network service handling device 2 is provided, which handles those calls for which the call handling device 1 invokes an intelligent network service.

Preferably, the device for handling calls consists of two parts, a first part 10 to receive calls in the mobile network and to send calls in the network, according to the routing information, after the application has been applied. routing information to calls. A second part 11 is a register or memory that contains routing information and routines capable of associating destination or subscriber information extracted from a call with the appropriate routing information. The first party 10 signals the information related to the call to the second party 11 (see arrow 101) and then the second party 11 sends instructions to the first party 10 based on the routing information found (arrow 102) .

The call handling device 1 further determines whether an intelligent network service is to be invoked for a given call. This is done by checking whether an intelligent network identifier is activated for a call being routed. For example, the subscriber information that is interrogated when determining the routing information may also contain predetermined data indicating that the subscriber has subscribed to an intelligent network service and may identify the service in question. If the processing performed at the device 1 for call handling decides that an IN service is to be invoked, an appropriate action is taken towards the device 2 for the IN service processing. In the example of Fig. 2, it is shown that the call is sent to device 2 for IN service handling (arrow 103). It can be seen that, similar to Fig. 3, a solid arrow in Fig. two represents a call (content and signaling), while a broken arrow represents signaling only. Referring to the example in Fig. 2, this means that if an IN service is to be invoked, then device 2 for service handling adds appropriate information to the call and sends the call to device 2 for handling of IN services, where further processing is carried out. However, it can be seen that it is also possible that the device 1 for the handling of calls holds the call and only establishes a signaling connection with the device 2 for the handling of IN services, in which information related to the IN service invoked is communicated to the IN service handling device which, in turn, responds by sending back appropriate routing and control information.

Returning to the example of Fig. 2, the IN service handling device 2 receives the sent call 103 and then executes an appropriate handling depending on the IN invocation information added to the call. If the result of the processing is a routing, the appropriately modified call is sent back to device 1 for call handling (arrow 106) which then forwards the call back to network 3.

The device 2 for handling IN services also preferably consists of two parts, namely, a first part 20 that receives the calls 103 from the device 1 for call handling, and a second part 21 that performs the processing. to determine the appropriate control information.

The IN service processing device 2 may be part of the mobile communication network, or it may be separate from it.

It can be seen that the parts 10, 11, 20 and 21 illustrated are functional entities, which means that they can be provided in a physical unit but, equally, they can be distributed in a plurality of physical units.

Preferably, the call handling system is arranged as shown in Fig. 3, namely as a system designed for GSM technology. Fig. 3 has already been described, and reference numerals equal to those in Fig. 2 refer to corresponding elements, so that it is not necessary to repeat the description. However, it can be seen that the present invention is, of course, applicable to any appropriate network system and to any appropriate IN scheme. In other words, it is not limited to GSM and CAMEL technologies. For example, network 3 could also conform to the UMTS standard, and the invocation of IN can then take place in any corresponding way. Element 20 will then generally be referred to as a service switching function (SSF) and element 21 will be referred to as a service control function (SCF).

The basic concept of the present invention will now be described, by means of the example illustrated in Fig.

1. Fig. 1 shows a call handling device 2 handling routine that determines whether or not an intelligent network service is to be invoked in the event that a routed call is a call ending on a mobile, that is, the routing treatment has determined that the destination of the call is a mobile station. In other words, the processing of a call handling device jumps to this routine when the stage of processing has been reached in which it is determined whether or not an IN invocation is to take place for such mobile-terminating calls.

In a first step S1, it is determined if it is active4

ES 2 227 261 T3 ford an intelligent network identifier for the destination or subscriber under consideration. Namely, as already described above, the first party 10 (GMSC 10) will have signaled a subscriber indication or an appropriate destination (for example, a directory number) to the second party 11 which preferably manages the treatment illustrated in Fig. 1. If in step S1 it is determined that it has not set IN identifier, then the procedure proceeds to step 56, which means that no invocation of IN takes place. Processing then returns to the main processing routine, which will continue without invoking IN.

On the other hand, if step S1 finds an activated IN identifier, step S2 is reached, where a processing is performed to determine whether a validity flag has been set for the activated IN identifier. The validity flag may be a single bit or flag that has the simple purpose of allowing the processing of steps S3 and S4 to be enabled or disabled very easily. Namely, by adding the characteristic of the validity indicator, it is not necessary to deactivate an identifier of IN if it is desired to avoid the processing of steps S3 and S4. Naturally, it is easier to enable or disable the specific condition comparison function by setting a single bit or validity flag, than to execute an on or off routine for an IN identifier. However, it should be noted that step S2 is preferable, but not necessary.

If the validity flag is set in step S2, proceed to step S3, in which a stored condition parameter is compared with a current condition parameter. As already mentioned previously, the condition to which the parameter refers can be an operational condition or a circumstantial condition. The operational condition may be, for example, the status of the mobile station, in which case the related parameter may be an on / off indicator, a busy indicator or, more generally, an indicator of the mode of operation. While the connected / disconnected indicator simply provides information about whether the mobile station is on or off, and the busy indicator simply provides information about whether the mobile station is busy, an operating mode indicator would have a plurality of states. , each corresponding to a mode of operation.

As an example, it is possible that the mobile station could operate in three different modes, the first of which was simply a paging mode, the second a telephone mode, and the third a multimedia mode. That is, in the first mode, the mobile station would only function as a pager, in the second mode as a normal telephone, and in the third, as a fully multimedia terminal. Of course, other modal hierarchies are possible and this is just one example.

The condition related to the condition parameter compared in step S3 could also be a circumstantial condition. Such a circumstantial condition could be the situation. The condition parameter associated with the situation can be, for example, a country indicator, a network indicator or a cell indicator (in case of a cellular network). Of course, any other parameters indicative of the situation could be used.

The circumstantial condition could also be the time related to the mobile station, that is, the local time for the mobile station or a global time, such as Greenwich Mean Time (GMT). If time is the condition, then a corresponding parameter could be a date stamp or a timestamp.

Following step S3, step S4 determines whether the result of the comparison performed in step S3 is that a predetermined requirement is met. The default requirement could be formulated positively (eg, stored condition parameter = current condition parameter) or negatively (eg, stored condition parameter + current condition parameter). If the predetermined condition is satisfied then an IN service is invoked (step S5) and, if not, then no IN service is invoked (step S6). The determination routine then returns to the main treatment routine.

The condition for which the comparison is performed will typically depend on the IN service activated. Likewise, the specific parameter (s) compared will also be chosen in conjunction with the specified IN service. Due to the large number of different IN services, there are a great number of possibilities. Likewise, the predetermined requirement checked in step S4 will depend on the activated IN service, the selected condition and the chosen parameter (s). There are also a large number of possibilities.

For example, if the IN service is a call-out service, this service may only be invoked during certain times of the day (for example, from 8 pm to 8 am) or only on weekdays. Similarly, such a call forwarding service may only be invoked if the subscriber is not in the cell to which his home belongs. In other words, the condition is the situation and the condition parameter is the cell identifier. The stored condition parameter would be the identifier of the cell to which the subscriber's household belongs, and the predetermined requirement in step S4 would be that the current condition parameter is not the same as the stored condition parameter. Another example that would lead to consider the situation as a condition is the aforementioned billing of the sending branch of roaming calls for prepaid subscribers, in which the corresponding condition parameter would be the network identifier.

A different example involving operational condition would be the use of a busy indicator as a condition parameter, in which case the call forwarding function would only be invoked if the busy indicator showed that the mobile station is busy.

Although the routine illustrated in Fig. 1 is a preferred example, a large number of variations and modifications are possible. First, Fig. 1 only depicts a basic routine illustrating the invention, and further steps could be incorporated into the procedure to determine whether or not an intelligent network invocation is to be performed. For example, preferably the known conditional activation function of CAMEL ph2 is also incorporated.

Also, although step S1 only mentions an activated iN identifier, it is also possible, natu

ES 2 227 261 T3 to determine if several IN identifiers are activated, whereby the routine shown by steps S2 to S4 could then be individually executed for each activated IN identifier.

Also, although step S3 only indicates comparing a stored condition parameter with a current condition parameter, it is of course possible to compare the current parameter with a plurality of stored parameters, for example, to determine whether the current condition parameter is found in a specific margin. Furthermore, it is possible to compare a plurality of condition parameters belonging to a given condition. For example, in case the condition is the situation, it is possible to make a decision based on the network identifier and the cell identifier or, in the case that the condition is the time, it is possible to make a decision based on the time of day and on the date.

Furthermore, it is clear that the predetermined condition checked in step S4 depends on the specific condition (s) and the condition parameter (s), such that a wide variety of requirements can be incorporated, depending on the specific effect desired.

In relation to the above-described basic routine and its various modifications, it is clear that the call handling device 1 must store the appropriate current condition parameter (s). In mobile communication systems, it is already known to store certain current condition parameters in association with information about subscribers, eg status and status. The update procedures for such parameters are well known and therefore need not be described in further detail now. If the comparison step S3 requires new forms of condition parameters to be stored (for example, the local time of the mobile station), then analogous update routines can be executed to keep the data on the device for call handling up-to-date. (for example, the HLR in the case of GSM technology).

As already mentioned above, the above-described routine of Fig. 1, or one of its many variants, is executed in the call handling device 1. Preferably, it is executed in such a way as to avoid unnecessary signaling and call handling as much as possible, which means that the routine must be executed in the register or in the memory in which the subscriber information is contained (information used to determining routing information on the basis of call destination information), that is, in the second part 11, which means the HLR 11 in the case of the GSM system illustrated in Fig. 3. Of course, it is also possible to execute the routine, or one of its modified versions, in the first part 10 (the GMSC 10 in the case of the GSM system), but this can lead to an unnecessary exchange of signals between the first part 10 and the second part 11.

Although the present invention has been described by means of specific embodiments, it is not intended to limit the invention to these embodiments, as the scope of the invention is defined by the appended claims. Also, reference numbers in the claims are for ease of reading, but are not intended to limit their scope.