FI116263B - A method, system and computer program for studying the quality of a cellular network - Google Patents

Description

116263

A method, system and computer program for studying the quality of a cellular network

The invention relates to a method for studying the quality of a mobile telephone network according to the preamble of claim 1.

5 Three methods are commonly used to study the quality of a cellular network: (1) an alarm system for detecting malfunctions and disruptions of cellular network modules, (2) field tests of cellular networks, and (3) end-user network malfunctions.

The quality experienced by the end-user of a cellular network is illustrated by the way his 10 cell phones use the communication capacity of the cellular network. When the call is not disconnected while the end-user is within range of the cellular network and the speech quality is undisturbed, the end-user experiences the quality of the cellular network. If, on the other hand, the call is disconnected for one reason or another, the end customer experience is poor.

15 The quality of the cellular network is good when the end user feels that the services provided by the cellular network are fast, uninterrupted and easily accessible.

* * · *

One way to measure the quality of your cellular network is to have uninterrupted calls. This means that the calls are not usually disconnected for other than controlled reasons.

• *

A controlled reason is the termination of the call by the calling or receiving subscriber.

. "'. 20 A controlled reason for disconnecting a call, for example, is that the paying subscriber's balance limit is reached or the payment instrument is exhausted. There are several uncontrollable reasons.

Uncontrolled causes may be due, for example, to the terminal itself, local: ***; mobile network or the number of terminals in the area. Terminals * · *. ,,.: Causes, for example, a hardware or software failure or low battery power ··. 25 calls. Reasons such as reflections and.;. duplicate channels.

• · * s * • The quality of the cellular network can be improved by changing the parameterization of the cellular network repeaters, changing the repeater to another type, or repositioning the repeaters.

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In accordance with the prior art, the mobile operator has had a central control which has been used to monitor the operation of the mobile network. Attempts have been made to install control elements for all elements of the entire cellular network in the central control room. The alarms received by the control panel from different elements of the cellular network indicate the condition of the various peripherals and are able to tell if there is a software problem or hardware failure. The advantage of having a centralized control center is that it can be quickly and efficiently investigated by the small maintenance staff at the control center.

There are also some shortcomings in the central control system. For example, the central control system 10 is unable to detect and indicate where there is a shadow area for the user that has no cellular network coverage. On the other hand, there have also been situations where, from the control room's point of view, the repeaters have been fine, but the repeater has not given signals to the intended area or has only given a signal so weak that mobile phones have not been able to utilize it. In addition, central control room tools are unable to detect a situation where the service level of the mobile phone field is deteriorating as a result of changes in the terrain, such as construction work.

Another prior art method for monitoring the quality of a cellular network is to measure the quality of the cellular network under field conditions by means of so-called TEMS measurements. In practice, TEM S measurements are performed using a special • • i »·: · mobile phone equipped with a computer and connected to a computer hardware. With this method, the cellular phone is able to analyze what it is seeing at any given moment: ***: the signals and parameters transmitted by the various cells of the cellular network and transmit them to the computer hardware for analysis. The computer software is often equipped with a map, 25 and maps the parameters collected by the mobile phone at each location.

• «·, · f Information is stored and available for mobile network design.

* · 'With TEMS measurements, field changes can be seen very accurately on the spot, and data can also be stored for later use. The disadvantage of this ·; · 'method is the very long time required to measure quality. In practice, TEMS- • *: In 30 measurements, one or more people drive a TEMS-equipped car in the '* area to be checked. The method of measurement is accurate in the area where it is used, but 3 116263 is very slow and expensive to implement. A car equipped with a TEMS instrument must be cross-checked at one of the base stations in order to identify problems.

One of the weaknesses of TEMS measurements is that they cannot see the mobile phone field values experienced by different phone types. For example, if you are using a Nokia 6150 brand cell phone to measure TEMS-5, the measurement does not tell you how different and different phones experience the quality of the cell phone field. These other brands and models include: Ericsson R310s and Nokia 9210 Communicator. There are cases in which certain brands of mobile stations cannot access the network, but there is a cloud in this particular type of mobile station, 10 although for other mobile stations it is only a slightly weaker cellular network field.

The third known technique for controlling the quality of a cellular network is customer contacts. High quality mobile operators have created channels for end users to receive complaints to review and improve the performance of 15 cellular networks. Customer contacts provide some information and suggestions for improvement over the cellular network. to improve the quality. However, this is not the most efficient way and • ·. end users always have enough interest in informing the mobile operator 'to improve their services. After all, very few end users report production problems on the cellular network. In the worst case, a dissatisfied customer will switch to a mobile operator rather than report a problem.

». ··· On the other hand, from the operator's point of view, the area complained of may be so remote that it will not be available in the near future '; send TEMS measurement resources. At the expense of the hooker, this approach may even seem to disregard the end-customer, and thus, '',: facilitates the end-customer switching to another mobile operator.

Thus, the known solutions described above present several problems or shortcomings.

:: On the other hand, there are very compelling reasons for maintaining a central control system and TEMS measurements, for example, but these tools are in any case expensive and slow ways to find cellular network issues that are reflected in the level of service experienced by end users.

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Indeed, it would be very useful for a mobile operator if the above monitoring methods could be improved or a completely new method could be created to better provide feedback on the level of service experienced by end users.

The ideal method would also be able to detect changes that occur over time with the age of the equipment if the equipment is not renewed or maintained frequently enough. A long-established mobile operator has a very large number of access points, and some of these access points may be the oldest model, and there is no business reason to replace all of them if everything seems to be working properly. The fact that a base station appears to be working properly does not necessarily mean that the base station will continue to operate tomorrow. The prior art does not describe a systematic way of detecting a failing base station if the central control station does not receive an alert for a base station malfunction.

The mobile network field may also change due to environmental factors: Obstacles, such as buildings, may weaken the driveway. For example, if a tall building is built between 15th Road and the Access Point, calls from customers on the road may be interrupted at the building. It is difficult for an operator to <> it. detect such a problem as the customer is unlikely to notify the operator of the · · call. This is because the customer does not know the reason for the interruption (eg, assumes,.,.: That there is a problem with their own device) and reporting requires time and care.

• * * '* ··' 20 The quality of the field brought to the end customer is also influenced by reflections.

Reflections come from buildings and other obstructions and waterways. It would also be useful to be able to detect these problems '· * ·'.

: * · *: The object of the invention is to provide a new type of method for controlling the quality of a cellular network, which enables to obtain information on the customer experience ....: 25 service levels.

The invention is based on the uncontrolled detection of:.,. · 'Lost calls, and in the event of a lost call, locate the one associated with the call

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! terminal. Positioning is typically done when the terminal reconnects to the network or very soon after reconnection. Call disconnection information and the location of 30 terminals are stored in a database where it is possible to extract those areas which generate a large number of disconnection notifications. Such an area may subsequently be inspected by another method.

More specifically, the method according to the invention is characterized in what is stated in the characterizing part of claim 1.

The invention provides considerable advantages. Namely, the invention enables to monitor the service level of the mobile telephone network experienced by the customer.

The invention will now be described by way of example and with reference to the accompanying drawings.

Figure 1 is a schematic diagram of one system according to the invention.

Figure 2 illustrates one example of a cellular network coverage area.

Figure 3 shows an example of the effect of construction on the coverage area of Figure 2.

Figure 4 illustrates an example of the use of one embodiment of the invention in the situation of Figure 3.

Figure 5 shows the regional accumulation of spatial coordinates of disconnected calls.

Figure 6 shows not only the location * coordinates of the disconnected calls shown in Figure 5, but also the locations of the base stations and the intended coverage areas of the base stations.

«· *» · • »

The system of Figure 1 comprises a Smart Network System 1 (Service Control Point), a Mobile Switching Center 2, a Home Location Register 3, a Home Location Register 4, a Location Information System 4, and a database 5. The system further comprises a control element 6. a mobile telephone network base station 7 and a mobile station 8 communicating with the mobile switching center 2 via base stations 7. The base stations 7 provide a terrain coverage area or ·: ··· coverage area 9, which means the area within which the mobile station 8 can receive ·; i 25 connect to said base station 7. In addition, various elements are shown in the figure; · Connecting lines or arrows describing the functions between the elements in question.

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The mobile telephone connection associated with the serving mobile station 8 is connected to the service of the intelligent network systems 1 for both incoming and outgoing calls. The incoming call is received by the mobile switching center 2. In this case, the subscription information is checked from the subscription database 3, which is parameterized for processing the calls received for that subscription 5 under the SCP 1. When the call is opened from the subscription, the MSC 2 checks the subscription information from the subscription database 3, which is configured to handle calls from the subscription under SCP 1.

By call, this generally refers to a circuit-switched connection. Thus, the call may be not only a voice connection but also a data call.

In the infrared system of Fig. 1, information on receiving and disconnecting a call is transmitted to the control element 6. A received call is a call selected to the receiving telephone number of the respective operator's network, the so-called B number (8 number of the mobile station).

In the infrared system of Fig. 1, information on making a call and disconnecting a call is transmitted to the control element 6. The established call is a call selected from the calling telephone number, i.e. the so-called A-number (8 digits of the mobile station).

According to an embodiment, information may be sent to the controller element 6 on all detected call disconnections or to pre-filter some of the disconnect notifications in one of the preceding network elements ·; ... · 20. The control element 6 should, however, be provided with information at least when the call is abnormally interrupted. Abnormal disconnection refers to the uncontrolled disconnection of a call. Uncontrolled interruption • »: '' typically results from signal weakness, hardware or software failure between mobile station 8 and base station 7 in mobile network or mobile station 8, or • · · ,; ; 25 environmental connection failure. Of particular interest are: Uncontrolled interruptions caused by a cause other than the customer's problems:: In the mobile 8.

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• I

In FIG. 1, the control element 6 receives from SCP 1 information about uncontrolled call termination and makes a request for spatial information with that interface information.

Hill '· 30 to Ice System 4. Spatial Data System 4 returns the position data a moment later.

There may be a slight delay in positioning, as location information is typically 7,116,263 only after the connection has been re-connected to the cellular network. Upon receipt of the spatial information, the control element 6 stores the interference event with its spatial information in a database 5, which information can be utilized in designing the cellular network and searching for problems in the cellular network.

Thus, in the system of Figure 1, SCP 1 is programmed to transmit call disconnection information to the control element 6. Preferably, a reason code is also sent at the same time to indicate the reason for the call disconnection. Information on call termination and reason for disconnection may be obtained from SCP 1, for example from mobile switching center 2.

As the positioning method itself, any suitable positioning method may be used in the system 10 of the example of Figure 1. For example, various network location methods are well suited to the system where the mobile network determines the location of the mobile station 8 based on cell IDs of the base stations serving the mobile station or calculates the location of the mobile station 8 from measured parameters such as propagation delay, signal strength 15 and / or signal arrival angle. The advantage of a web positioning method is that the positioning method is in the operator's possession and its implementation does not require any intervention or investment by other parties. Of course, as a positioning method * ·, a method may also be used that requires action by the client terminal 8 or a subscriber module connected to the terminal (e.g., a SIM card).

• · ... 20 The positioning method can also be satellite positioning, for example GPS • ·: '1! t system.

• ·

With the system shown in Figure 1, a method can be implemented which: detects call termination due to the fact that the mobile station 8 and; '; disconnecting the mobile communication network uncontrollably, 25 - locating the mobile station 8 to which the connection was lost, • »- informing the call termination information to the control system 6, - - adding information to the database 5 for detecting problem areas.

The positioning can typically be performed only after the mobile station 8 reconnects to the mobile network. Here, too, there are more than 8,116,263 options for positioning. The mobile network can be. for example, tune in a function that locates mobile station 8 as soon as the mobile station attempts to re-register to the mobile network. Another option is to try to locate a particular predetermined sequence. Such a sequence may include, for example, five attempts 5 such that the first positioning attempt is made 5 to 10 seconds after disconnection. For example, the second attempt could be done within 10-20 seconds, the third attempt 20-30 seconds, the fourth attempt 1-2 minutes, and the Fifth attempt 5-10 minutes after disconnection. Positioning is stopped as soon as the positioning is successful, typically about 1-3 positioning attempts are made. If, in this embodiment, the mobile station 10 8 is not located after the fifth attempt, the location is terminated and the location of the call termination is not stored in database 5. There are two reasons for stopping location: first, the mobile is likely moving over time; 8 may be offline for hours and 15 continuous locating would waste resources. For the positioning, or at least the use of location information, a time limit should also be set in the first embodiment, where the mobile station 8 is located when the mobile station 8 re-registers to the mobile network. The time limit can then be, for example, between 5 and 10 minutes.

• ·

Once the unconnected call is received with location information, the call 20 and associated location information may be stored in database 5. Preferably, the reason for the call termination is stored in database 5 as well as the reason for the disconnection being generally known by the mobile network. Another '··· * option is to add call disconnection information to a mathematical representation stored in database 5 such that the representation describes, for example, some sort of distribution or cumulative function of disconnected calls without having to store in database 5 • »*; * Separate information for all lost calls.

4 ») <I * ·. ··. In an embodiment of the method, the reason code is analyzed before sending the positioning request to the positioning system 4. It is then possible to filter already

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in the initial phase, cut off calls due to a controlled reason or »| 30 for uncontrollable reasons that are not of interest to the mobile operator. This can reduce the network load on the location requester.

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By using the above method for a sufficiently long period of time, it is possible to extract from the database areas that are more environmentally aware of uncontrolled disconnected calls. If the concentration is very local and the frequency of interrupted calls is significantly higher than in the immediate area, the condition and coverage of the mobile-5 network should be checked in the vicinity of the concentration. The worst problem areas should be revealed after a few days or weeks of use.

In particular, problem areas can be searched by comparing the number of disconnected calls with the number of disconnected calls in the immediate area, since the effect of call density on the number of disconnected calls can be at least partially compensated for. Another option 10 is to relate the number of uncontrolled calls to the volume of traffic in the area. In any case, the problem of a mobile network can be more effectively detected if some method is used which relates the number of disconnected calls to the amount of traffic (number of calls or preferably seconds or number of simultaneous calls). This is due to the fact that uncontrolled calls are also occurring due to faults in the client terminals or, for example, when the battery of the mobile station 8 runs out of call. It will be appreciated that such cellphone-independent call interruptions will accrue more in areas with higher call density. Of course, it is possible to look at the number of unconnected calls t 20 also in absolute terms without proportioning to the amount of traffic. In this case · ... · the problem areas with the most traffic are highlighted first and are therefore the most important for the operator.

• · * |

If the cellular network is capable of providing accurate reason codes, the accumulated call interruptions can be analyzed by reason codes. Hereby more information can be obtained and possibly more sensitive to detecting some defects in the operation of the mobile network. The analysis can also group reason codes when constructing representations and. ···. missed calls with some specific reason codes may be excluded from the cumulative presentation! sequence. It is, of course, also possible to disregard the reason for the call being disconnected and to make cumulative representations of all disconnected calls, whether they were disconnected in a controlled or uncontrolled manner. However, in such an embodiment, the sensitivity of detecting problem areas remains weak, even if the accumulation is proportional to the amount of traffic.

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Analysis of a report from a cellular network requires a good knowledge of the cellular network from the cellular operator. The spatial information system only provides spatial coordinates that cannot be used as such. Figure 5 shows an example of a map where the received interference information coordinates 20. The interference information 5 coordinates 20 refer to the location information associated with the interrupted call which is stored in the database according to the classification method used or taken into account when generating the interrupted call presentation.

In addition to spatial coordinates, the cellular operator must be able to map both the locations of base stations 10 and their planned cellular network coverage areas to identify potential issues. Such a representation is illustrated in Figure 6.

As noted above, a certain amount of time elapses between call termination and mobile location detection, as a mobile station that is not connected to a mobile network cannot be located. As a result, no location information can be retrieved in areas where the mobile station cannot find 15 cellular networks. Location information is thus obtained in the immediate vicinity of such a problem area, i.e., the area where the mobile station returns to the cellular network. In practice, therefore, the area marked on the map by • ♦. there will be a large number of spatial markers around, requiring closer examination. The exact areas in which the spatial coordinates are collected usually work * · ... 20 without any problems. A closer examination of the problem area can be performed; · '· # Using a cellular network control room or using, for example, TEMS measurement.

• · *>

The number of spatial data markings on the map does not indicate the severity of the potential problem; instead, the number of spatial data markings has to be commensurate with the terrain, the possible disproportionate penetration • of mobile devices in the area. This also means that the number of calls made in the area is taken into account in the analysis.

»: Spatial information will also appear on the map for end customer behavior; for example, when the battery is running out of power, the call is interrupted. Cellular network: ': From the standpoint of running out of battery, the call will end abnormally.

t »» • »'' There is one requirement in Finnish telecommunications legislation that the location data of subscriptions should not be retained. This requirement can also be fulfilled by not storing in the database 5 the identification of the parties to the call (A, B or C subscriber identifiers), but only 11 116263 for each broken call, only the data needed for the cumulative analysis, such as: call termination, error type, date , time, and location. For example, the time difference between the call termination and the location can also be stored as additional information, which may be useful when performing analyzes 5.

Figures 2, 3 and 4 show an observational example of a change in service level associated with a mobile network and the operation of an embodiment of the invention in connection with a change of environment. Figure 2 shows a base station 10 of a mobile network serving mobile network users on a highway 11. Fig. 10 shows two cells 12 and 13 of a mobile communication network which a base station 10 forms on a road 11 in succession. Figure 3 shows a building 14 to be constructed between the base station 10 and the road 11. The new building 14 overshadows the field provided by the base station 10 and creates a barrier to radio communication between the base station 10 and the part of the road 11 behind the building 14. At this point, a shaded area 15 is created, where the call of the user of the mobile station 15 traveling on the highway 11 is interrupted. Thus, the new building 14 changes the environmental conditions such that the cellular network is no longer able to provide the coverage that was originally designed by the operator. However, the operator is not automatically aware of such changes, and it may take very long time for known technology to uncover the problem.

* 20 At worst, the problem will only become apparent after several years of redesign of the mobile network '· · · *.

• »· • ·

Figure 4 illustrates the operation of one embodiment of the invention in the above problem situation. Calls to the mobile network users on the highway 11 will be interrupted at Building 14 due to the loss of the connection. In this case, the mobile network 25 informs the controller element 6, the SCP 1 or another suitable one. : Controls the call for disconnection and gives the disconnect a reason code.

. ''. The mobile station is located and the received position information is stored in a database. After this .! the location data stored in the database is displayed on the area map. In the example of Figure 4; , spatial information is marked with an asterisk 16. In the example, for the sake of clarity, only 16 of the spatial data are shown. In practical applications, spatial data 16 may accumulate in problem areas in large quantities, so that marking the spatial data with stars as in the example of Figure 4 is not practical. Thus, 12,116,263 can be used to represent spatial data, although colors that represent the density of the received spatial data in the area of the map point. Of course, in other embodiments of the invention, another suitable representation may be used, or a computer system may be programmed to present data of the problem areas pre-analyzed without any actual graphical representation.

Figure 5 shows another example of the accumulation of spatial coordinates. In the example, a plurality of spatial information points 20 are depicted. In Figure 6, the spatial information points 20 of Figure 5 are located on a map depicting cells 21, 22, and 23 of the cellular network. The figure shows that spatial information points 20 accumulate around cell 22. functioned properly. The function of cell 22 should therefore be checked.

With the above embodiments, abnormal disconnections in the cellular network can be recorded and recorded. Examples of registered data include interruptions in calls or data transmission due to the coverage area. Depending on the embodiment, these error conditions provide position information, date, time 15, and possibly also the cause of interruption. If statistically large numbers of these error events occur, a more accurate cellular network measurement can be performed in the area in question, for example using TEMS measurement. The embodiments thus speed up the detection of problems in the cellular network and thus improve cost-effectiveness. Application forms that are present in the cellular network • |. 20 problems can be solved faster.

* * · ·

Finding problem situations and cases faster, and even proactively, • ·

»I

improve the coverage and quality of service provided by the cellular network. This in turn • · * t · '..! Improve end customer loyalty.

• ·

Thus, the above examples can be used to make various summary presentations, «| ., · · 25, which can be used to examine the quality of service experienced by end-users of mobile networks: .... From the mobile operator's point of view, such a procedure yields: faster problem cases are detected and, moreover, corrective actions * »* are easier to prioritize. In this case, from the end customer 's point of view:. Operator service is consistently good because the mobile operator is • »·« 30 capable of responding quickly to a variety of coverage challenges in key geographic areas.

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Depending on the network technology used, the above reason codes may be, for example, "" ringing tone "," busy "," off network "," network error "," B subscriber closes "and" A subscriber closes " ". Of the above reason codes, the codes "" telephone alert "," busy "," B-subscriber closes "and" A-subscriber closes "are not related to uncontrolled disconnection of 5 calls. Some networks are also able to tell where the error occurred in the event of a network failure. In this case, the reason code may indicate, for example, the following errors "" error from the mobile station "," central network error "," air interface error ", or" "inter-network communication error" "or" central gateway error ". In various embodiments of the invention, available reason codes may be used in a manner appropriate to each application.

Embodiments utilizing web positioning can be used in such a way that the end customer does not notice the use of the method at all. Such embodiments can be used extensively and without disturbing customers.

The embodiments may also be used in such a way that no location information is provided to the service operator, but that any location information requested for the use of the embodiments is kept available only to the network operator. This does not compromise customer privacy.

The foregoing examples are intended to illustrate the use of the invention and are not intended to limit the scope of the invention as defined in the patent claims. * The above examples may be modified in a number of * 4 * • | 20 ways. hardware components may be implemented in a variety of different ways, for example, the control element 6 or other control element of Figure 1 may be part of a mobile communication network. It is also possible to »| I« ';' 25 perform a method of locating a mobile station based on information available '' from a broken telephone connection. In such an embodiment, • · »* · · ' i requires the mobile device to reconnect!, (<· 'to the mobile network. The location of a mobile station could be such

t I

In an embodiment performs, for example, the last 30 base station configurations associated with the dropped call based on cell IDs.

Claims (12)

A method for monitoring the operation of a cellular telephone network, in which method: - an interruption of a connected call to a mobile telephone (8) is observed, and 5. the mobile telephone (8) to which the observed interrupted call was joined is characterized by: the location is carried out where the mobile phone (8) eats is connected to the network or rather quickly after the connection. 10 Method according to claim 1, characterized in that the interruption of the call is observed by means of the functionality of the mobile telephone network. . Method according to claim 1 or 2, characterized in that • φ. After observing the call interrupt: '· "; - a causal code for interrupting the call is analyzed, - on the basis of the analyzed reason code is determined whether it is a • ·. · * · , uncontrolled interruption of the call, and - the mobile phone (8) is located only if it is determined that the call was interrupted * ", * 20 uncontrolled. * · T t I 4. A method according to any of claims 1-3, characterized by: <: that the information about the interruption of the call and the position received for the ":": location of the mobile phone is stored in a database (5) (8) 116263 Method according to claim 4, characterized in that after locating the mobile telephone (8): - a cause code for interrupting the call is analyzed, - on the basis of the analyzed reason code it is determined whether it is an uncontrolled interruption of the call, and - in a database (5), the information about interrupting the call is stored only if it is determined that the call was interrupted uncontrollably. Method according to any of claims 1-5, characterized in that in the process the cause code for interrupting the call is obtained from the mobile phone network and in the database (5) the received reason code and the position received at the location (8) are stored. Method according to any one of claims 4-6, characterized in that the position points associated with the interrupting of the calls are obtained from the database and a graphical representation is generated, where the obtained points, the position points and the distribution of the position points are presented. on a map bottom. • · t I Method according to any one of claims 1-7, characterized in that: in the method: - · · · · - the interruption of the call is observed due to the connection between the mobile telephone network and the mobile phone (8) is interrupted, and • The '·' mobile phone (8) is located, where the mobile phone (8) eats is connected to the mobile '* * ·' telephone network. 25 116263 Method according to any of claims 1-7, characterized by a 11 in the method: - the interruption of the call is observed because the connection between the mobile telephone network and the mobile telephone (8) is interrupted, and 5. the position of the mobile telephone (8) is reconnected. in accordance with a predetermined sequence for locating the mobile telephone (8), since the mobile telephone (8) eats is connected to the mobile telephone network. Method according to Claim 8 or 9, characterized in that the location is terminated after a predetermined time after the call is interrupted, or the received position information is rejected, unless the time interval between the location time and the call's interrupt time is greater than a predetermined time limit. 11. A method according to any of claims 1-10, characterized in that the method of accumulation is sought, in which location points: · associated with uncontrolled interrupted calls are collected more abundantly than in the environment. f i A method according to any of claims 1-11, characterized in that the call is a circuit-switched audio or data call. . ... 20 k k k * k s • <f • · t i>