Method and system for collecting traffic data

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DESCRIPTION

Procedure and system for collecting traffic data.

Scope of the invention

The present invention deals with the collection of traffic data by means of a network of mobile stations.

Background of the invention

The need to monitor the speed of means of transport, especially vehicles used in road traffic, has been demonstrated. It has been widely demonstrated that there is an overriding need to avoid traffic jams and to carry out road route planning, where the collection of vehicle-specific data carried out in real time will allow statistical analysis of the traffic, as well as a performance comparison.

There are currently good methods to track instantaneous speed, for example police use radars to monitor traffic. In addition to these systems, the pressure-sensitive loop method of passing vehicles can also be used. However, neither radars nor the loop method allow the vehicle to be detected and it is not possible to make a reliable measurement of average speed, for example.

For example, in the Helsinki region, image identification methods have been used to collect traffic data. A camera is placed in a section of the road that will take images of the passing vehicles. At another point on the road, a second camera is placed to take the corresponding photographs. An analysis system, as close to real time as possible in the best of cases, identifies the license plates of the photographed vehicles. If both cameras have taken a picture of the same license plate, the average speed of the photographed vehicle can be accurately determined. In the Netherlands, they have connected a speeding ticket printing device to the analysis system to print the payment orders of the owners of the speeding cars.

When real-time traffic data is required from an area of ​​a large road network, the image identification method described above presents as many drawbacks as it requires large investments, since its construction is expensive, as well as the cost of construction. maintenance of measurement stations. In addition, data transmission connections cost money and the calculation of the capacity required for image identification is not free either. The method also suffers from inclement weather, which reduces its use, especially in countries where rain, snow and fog abound.

A network of mobile stations has long been used to locate the subscriber. The use of a network of mobile stations is also a well known method of collecting traffic information. In the following patents reference is made to two publications: US 5,933,100 and WO 01/23835 on the current state of the art.

US Patent 5,933,100 shows how a measurement of data from a GPS system is transmitted through a mobile station to a data system that calculates the average speed of each section of the road.

In the PCT application of publication WO 01/23835, the terminal equipment contains special software to follow the change of the cells of the mobile station network and inform the system about said changes. In a prototype, the system calculates the location and speed of the mobile station based on the location of the transmitting-receiving base station and the distance between the data transmission terminal equipment and the transmitting-receiving base station for networks. mobiles.

In another prototype (page 61-63 of the PCT document) it is proposed that the situation of the mobile station can be collected from the transmitting-receiving base stations in flight. The information that is collected may consist, for example, of periodic beacon transmissions from the terminal equipment to the network. It is also mentioned in the application publication that the situation of the mobile station can be shifted through the service switching point of the mobile station system, in which the aforementioned periodic beacon transmissions can be collected from the traffic at the point switching services.

If the equipment owned by the users of the mobile station system is taken into consideration, the solution offered by the application publication Wo 01/23835 does not seem feasible, as it presents fundamental problems. First of all, the terminal equipment is necessary to transmit extra messages to the network that could cause unnecessary overload of the air interface in high traffic areas. In addition to unnecessary traffic, the consumption capacity of the terminal equipment must be taken into account. Second, the solution presented requires modifications of the terminal equipment, for example, the installation of an additional application, which means that the solution cannot be applied in existing mobile stations and that the application itself will not work with equipment. terminals from two different manufacturers. Third, the collection of messages from the network will not be successful if the messages are protected.

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Accordingly, the current art does not offer an ideal solution for a traffic data collection method and system using a mobile station system without changes being made to normal mobile stations or without much user intervention. Furthermore, one of the most difficult problems to resolve in the state of the art is related to the protection of people. The privacy of the user is threatened if its movements can be tracked, even if it is argued that such monitoring is for the public good. If a system of this type is used to collect data on traffic that implies that users are identifiable, it will be necessary that said users give their consent even in cases of minor importance. A difficult situation would be created if a user did not agree to consent once the general application of such methods has been developed that affects all users of the network.

Summary of the invention

The purpose of the present invention is to provide a solution that makes it possible to eliminate the problems that have been discussed above. This can be achieved using the method or system set out in the independent claims. The zones are searched from the network, where the user's terminal equipment and the network exchange zone-related messages. The time of arrival of the user to the first zone is stored in accordance with the signaling used by the network and the terminal equipment. The stored time of arrival is then compared with the time of arrival of the user to another area, which is pertinently obtained as the result of the signaling carried out between the network and the terminal equipment. From this information on time, the time required by the terminal equipment to travel the distance between two points is obtained.

If several users move through the area, the measurements described above can be taken, for example, on all parts of the terminal equipment present in the area. Statistical distributions are obtained from the sets of times stored in this way that can be used to determine, for example, average speed and traffic anomalies occurring in the connection sector.

Tracking the identity of the subscriber must be resolved by the mobile station system. For example, in the GSM system, the use of the user identification IMSI (International Mobile Subscriben Identity, International Mobile Subscriber Identity) is usually avoided for reasons related to the security and protection of the user, replacing the IMSI identity with a TMSI ( Temporary Mobile Subscribing Identity, Temporary Mobile Subscriber Identity) that will be modified according to certain criteria, for example, updating the zone changes. In a prototype of the present invention, TMSI identity modifications are tracked in order to determine the arrival of a user to another area. Because the TMSI identification is used in the application of the present invention, it is not necessary to find the interdependence of the IMSI and the TMSI in the network registry.

With the aid of the present invention it is possible to determine location pairs and even partially interconnected entire networks that are required to obtain data on traffic. The location pairs of the partially interconnected network can be determined with the help of a signal analyzer that combines the data available from the signal analysis and, for example, the location of data from a satellite or a mobile telephone network or by analyzing the radio measurement data related to the areas to be determined from the signaling traffic of the mobile station network.

For example, the areas where the location area changes may be mobile station systems areas. The solution according to the present invention can be applied in practice by following the signaling related to the change of the location zones of the system. Of course, the present invention is not limited only to GSM or UMTS station systems, but within the scope of the concept of the invention defined in its claims, it can also be applied to other network applications that allow the movement of users. , for example, to a GPRS or WLAN type packed data switching network, in which the arrival or departure of an area can be determined, for example, from transmissions related to changes in the packet routing area.

Graphics ratio

The principles of the present invention are listed below with reference, by way of example, to the accompanying drawings, in which:

Figure 1 shows the operation of a mobile station system according to the current state of the art,

Figure 2A shows the operation of the method according to the present invention in the assumption of a vehicle traveling on a road in a first direction,

Figure 2B shows the situation corresponding to a vehicle moving in a second direction,

Figure 3 is an example of a system used for the application of the present invention and,

Figure 4 is an example of the information that is needed to analyze road traffic data collected by a mobile station system.

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Detailed description of the invention

The application of the present invention is suitable, for example, for a mobile station system of the type shown in figure 1. The principles of the operation of the system will now be discussed in greater detail in terms of its parts that are affected by the present invention.

The mobile station 101 is located in a PLM network which in the current case is a GSM network. As a general rule, the mobile station is connected to a network through a radio interface in which the base transmitter-receiver stations (BTS) located in the network form cells (111-125). Each transmitter-receiver base station is connected to a base station controller (BSC) 104, 105 located in the network, either directly or by switching through other transmitter-receiver base stations.

The base station controller controls the operation of the radio network and regulates the radio frequencies and time slots used by the mobile stations and the transmitting-receiving base stations that constitute the terminal equipment. The base station controller makes the necessary decisions based on the results of the measurements transmitted by the different elements of the network and the terminal equipment. Furthermore, the base station controller directs incoming traffic from the transmitting-receiving base stations to the mobile switching center (MSC) 103. A visitor location register (VLR) 102 is connected to the mobile switching center . The VLR maintains a register of the users located in the area and the services requested.

In order to direct the incoming call or message to the mobile station 101, collaboration between the different parts of the system is required. Initially, it is necessary to search the subscriber's home location record (HLR) using the mobile station to identify the switching center serving the subscriber. Then, when the call or message has been directed to the relevant MSC 103, said MSC requests from the VLR 102 the part of the radio network to which the subscriber belongs. The VLR returns the identification of the location zone (LA). The MSC then sends a location command to the BSC 104. Said BSC orders the location of the user to the relevant transmitter-receiver base stations. In order to avoid having to search over a very large geographical area, for example an entire country, when the subscriber is located (since it is usually well located somewhere), the radio network is divided into location areas. Multiple location zones may belong to the base station controller zone.

The mobile phone follows the audible broadcast control channel (BCCH) in the cell. This channel has information on the frequencies and identifiers, among others, used by the cell and adjacent cells, the order of the frequency hopping and the paging groups.

The terminal equipment measures the transmission of cells that have the highest audibility and whose cells are present in the host cell's BCCH channel at that moment. According to the GSM definitions, the terminal equipment decodes, in addition to the host cell, the six cells that have the highest audibility and from which the BCCH channel is monitored. When the signal strength of the cell used by the terminal equipment is as weak as the signal strength of a new cell with better audibility, the terminal equipment switches cells.

The terminal equipment listens to the BCCH channel, for example, at 4 second intervals. The cell identifier is the global cell identity (CGI), from which the localization area identification (LAI) is obtained from the BCCH channel. As can be seen in Figure 1, the LAI A localization zone is formed by cells 111-114, the LAI B localization zone by cells 121-123 and the LAI C localization zone by cells 124 and 125. When the terminal equipment perceives that a new cell has a different LAI than the cells that had the best audibility a moment before, it reports this to the VLR so that the terminal equipment is available for the methods described above. For this purpose, in the simplest of cases, 1) the MS allocates a channel of the new BTS, 2) the MS transmits a Location Update Request to the MSC. 3) the MSC updates the information for the VLR. 4) the VLR transmits a Location Update Complete message to the terminal equipment.

If the location zones are located in zones with different VLRs, the following steps should be followed in addition to those described above: 3 ') the new VLR searches the user information in the old VLR, 3 ”) the new VLR looks up the user's information in the HLR. In addition, 3 ”') the MS and the new VLR comply with the security procedures, 5) the new VLR updates the information changed from VLR by the HLR and 6) the HLR cancels the old location, either after having found that the location zone has changed or if the old VLR prompts you to cancel the location specification.

In order to avoid many continuous changes of the locating zone there is a special hysteresis mechanism to effect the changes of the locating area, that is, the locating area is not changed immediately after the change of the locating zone defined by the The area of ​​the cell with the highest audibility, but there is a wait until the difference in signal strength is high enough. The operator himself can determine the required hysteresis reselection parameter between locating zones, for example within a range of 0-14 dB. As a default value, some equipment manufacturers use a value of 6 dB.

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In the selection of the location area, the messages 1) and 2) transmitted by the terminal equipment should in principle be provided with the subscriber identification (IMSI, International Mobile Subscriber Identity). Likewise, the messages 4) transmitted to the terminal equipment should be addressed to the subscriber using IMSI. In the same way that they can be eavesdropped on the air interface, certain hostile elements can track users of the mobile station network without the users realizing it. In order to avoid this, a pseudo-identification is used, a Temporary Mobile Subscriber Identification (TMSI) that an external observer could consider as a random number. The relationship between the TMSI and the IMSI is stored in the VLR and in the phone.

The operator can select the criteria on making the changes to the TMSI. For example, calls originating from the terminal equipment location zone changes can cause the TMSI to be updated. The update is carried out by means of an encrypted message, through which the TMSI is transmitted in encrypted language. The terminal equipment receives the message and decrypts the encrypted TMSI using its own encryption key, whereupon the terminal equipment begins to use the new TMSI.

Based on the TMSI it is not possible to reveal the identity of the user (ie the IMSI), unless there is an opportunity to examine the contents of the VLR or the subscriber identification module located in the terminal equipment.

Some operators do not use the TMSI, whereby the IMSI is used in messages that are transmitted over the radio interface, which constitutes a risk to data security. In addition, some operators have modified their criteria for updating the TmSi, so that the TMSI is updated less frequently. When the user is on the move, their safety is also at risk. In technical terms, the identity of the subscriber, which can be tracked, is unimportant from the point of view of the present invention, except that its application is easier when the identification of the subscriber remains unchanged.

The basic principle of the present invention is shown in Fig. 2A, in which the imaginary locations of the transmitter-receiver base stations are indicated with asterisks. Normally, the location areas of mobile station networks are made up of cells formed in turn by a transmitter-receiver unit located at least in one transmitter-receiver base station and the location area usually comprises cells of several base stations transmitters-receivers. The subscriber 201 of the mobile station system travels along a road S as a function of time, a point S (T) being in the location zone 212 at the moment T when the photograph is taken. When the user has traveled a sufficient distance within the location zone

211 at point S3, so that the location update is fulfilled in accordance with the hysteresis conditions, the terminal equipment will send a Location Update Request message relative to the area as a signaling message to the network. The TMSI reserved for the user at that time is associated with the message, as explained above. If the conditions for updating the TMSI have been made so that said TMSI is modified in relation to the location update, then the subscriber will already have a different TMSI in the location area 211. If the operation of the network is sufficient and without delay, then in immediate proximity to point S3 a Location Update Complete message is also obtained which is transmitted as a signaling message. However, this is directed to the new TMSI, since if, for example, the VLR is changed, the TMSI will be changed in the security procedure of item 3 "'). The terminal equipment will send a request 2) and receive a message 4) through the cell of the new location area.

If any of the above location update messages is collected from the traffic between the transmit-receive base station and the VLR, it can be seen that the user, whose identity is TMSI1, is a point S3 of time T3. If the TMSI update messages and the corresponding location update messages of the corresponding location update messages are also collected from the traffic between the location zone

212 and the transmitter-receiver base stations and the VLR, it can be seen that the identity TMSI2 has been a point S2 prior to time T2. It could be verified that the messages arrived earlier from the location area

213 that point S1 had been exceeded even at time T1, where the identity TMSI3 was a temporary subscriber identity.

The situation is simpler if the TMSI does not change. The system can be set up to track, for example, users arriving in zones S1 and S3. When the same identity is observed first in S1 and then in S3, it can be concluded that the user has been traveling on the road for the distance S1-S3. The same procedure can be used if a static IMSI or TMSI is used in the message traffic, but in this case the anonymity cannot be considered as complete, although the mobile station is tracked to some extent.

It has been verified through tests that the location update zones (S1, S2 and S3) remain constant and with good precision because in practice the resolution is approximately 100-300 meters. Weather conditions or the presence of a phone in the vehicle may have less of an effect on the location update zones because the location zones on both sides of the location update zone often suffer from a radio environment of the same type. . The resolution depends mainly on the length between the points of the BCCH channel measurements made by the terminal equipment, which in this case is of the 4-second type.

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As can be seen in Figure 2B, when the return is made, in accordance with the hysteresis rule, through the second direction following the path S ', the location update zones are located in a different place due to the difference The required 6 dB in each direction, in the case illustrated by way of example, makes a total difference of 12 dB in signal power. In good weather, it is equivalent to several kilometers. The differences are illustrated by dotted lines between Figures 2A and 2B. The dotted lines show a projection of the difference of the distance in the coordinates of the road following the direction of that road. The roads that the vehicles travel can actually be quite different when compared to the points on the coordinate map because the horizontal alignment of the road network can change and, in addition to that, so can the signal strengths, that is, they may vary due to the steering effects produced by the obstacles presented by the terrain. For this reason, two separate points should be used that are obtained by taking separate measurements in each direction.

In Figure 2A, zone SI corresponds to the transfer from a location zone 214 to a location zone 213. Similarly, zone S2 corresponds to a transfer from location zone 213 to location zone 212 and S3 corresponds to the transfer from location area 212 to location area 211. In Figure 2B, zone S1 'corresponds to the transfer from location zone 213 to location zone 214, S2' from zone 212 to zone 213 and S3 'from zone 211 to zone 212.

This invention can be applied by building, for example, a system according to figure 3 relative to a mobile station system according to figure 1. For this, network elements are added to the system, such as a signal analyzer 351 that monitors the traffic that occurs between the transmitting-receiving base stations and the base station controllers, among whose traffic these messages are also transmitted. are displacing as they are important to the application of the present invention. The signal analyzer will preferably be connected to point P1 to monitor signaling traffic occurring on a 2 Mb E1 cable from a transmitting-receiving base station to a base station controller. Multiple signaling lines to be followed can be connected to the same base station controller (P2 in the example shown). Accordingly, in solutions offered by various vendors, an analyzer can monitor between eight and sixteen E1 connections, each of which 12 transmitter-receiver units, ie TRX units, can typically be connected to GSM technology. The signal analyzer can be connected to the Internet and through this connection it is possible to determine in advance which messages should be followed up through a separate connection reserved for control purposes, if it is advisable to keep the easy readjustment of the equipment settings. The messages to be tracked can also be permanently configured in the signal analyzer, where a modification of the type of task will require updating the software.

Optionally, the solution can also be applied using elements of the signal analyzer type 352, which are connected through points P3 to monitor the traffic between the base station controller and the switch point of the base station. 303 service or VLR 302. Because data transmission systems use transmission lines with a higher capacity for individual connections, which represent the highest level of the network topology, and because connections at a higher level of the topology also cause a greater framing of signaling traffic, in this case the system will be, in general, a little heavier.

The solution can also be implemented by making the necessary changes to the transmitter-receiver base stations, the base station controllers, the service switching points or the VLR. In this case, the address to which information about the messages to be tracked should be sent is also determined by the item in question, in addition to the messages to be tracked. However, this alternative requires making modifications to the existing hardware structure, which tends to have a high cost and longer delivery times. However, it is possible to apply this alternative in connection with updating the version of the network elements.

When the signal analyzer 351 detects a message of the desired type based on the identifier contained therein, it will send to the address of a predetermined server 350, the time and information contained in said message, in addition to the predetermined information. The server address can be, for example, an IP address or any other address of the server on the network, to which a portal must be associated, to which the message is sent. The signal analyzer can also transmit the message it has detected in turn.

As predetermined information it is not necessary that there be other than that of the signal analyzer, that of the base station controller, some address of the transmitting-receiving base station or the identity of the location area. It is not necessary to transmit the time because in a network that is not congested the time of arrival of the information to the server 350 can also be used as the incidence time. Regarding the information contained in the message, at least the identity of the mobile station is specified, which, depending on the case, may be TMSI or IMSI. In addition, in a refined prototype, the identity of the location area and the type of message are also transmitted. A refined prototype can also track the modification of TMSI identities, as well as changes in location zones.

The traffic data calculation server 350 receives the location zone update messages. Update messages can also be processed in their order of arrival through a FIFO buffer, in which new subscribers are added to the track when said subscriber identity

ES 2 323 167 T3 reaches a measurement point that has not been detected before. Similarly, messages related to identities that correspond to other identities that are already being tracked can be used directly to calculate the time difference and speed. The information is stored based on the update messages, for example, in a traffic database 355 connected to the server. The LTK traffic database is applied as a real-time database and can be used with CORBA-type subscriber connections. The calculation server 350 may be available via the Internet to different separately defined connection modes. For this purpose, the calculation server is provided with protocols 360 that allow exchange protocols, which can be, for example, HTTP or FTP. The server can also be timed to periodically transmit the test results, and the transmission interval can be set separately for each road section. Information on high-traffic road sections is updated more often than information on areas with less traffic. The criteria related to the number of interventions can also be set as the update interval.

Figure 4 shows the information to be stored in a traffic database. Information can be stored in a database on road sections maintained by the server. In this way, a larger system can be built using efficient computer hardware. On the other hand, this system can be considered as an alternative, since it only contains two measurement points, so the load on the server and the database will continue to be less. One system analyzes a section of the road and extracts the relevant data, so that it will be available to other external systems. The information provided may contain distributions or parameters that represent the assumed normal distribution, such as a mean value, the divergence between the distribution of the measurements and x², which can be calculated, for example, from the difference between a curve adapted to the material and the measurement points. The value of x² indicates how well the fitted curve follows the measurement results, so values ​​in the range of [0, 1] mean that the curve fits the error limits of the points. In the adaptation process, some of the material may be left out of consideration, for example, at the extremes where these incidents, which may arrive too quickly to their destination (process error) or too slowly (a departure during the tour or a vehicle crash). In its simplest form, the desired traffic data is simply the time taken to travel between two points, for example, "the journey from Helsinki to Lahti takes 1 hour 20 minutes on average."

Database 355 (FIG. 4, A) stores changes in the location area of ​​each subscriber identity that has been detected in network traffic, based on a location area on a section of the road. In addition, the real clock time corresponding to the message is also stored. Several road sections (B) from which the corresponding information is stored can also be connected to the database.

If the operator uses TMSI identifiers, a record of them is also kept (C, D). The TMSI identifiers can be detected in the traffic between the transmitting-receiving base station and the BSC or, analogously, from messages on their way to the MSCNLR.

It is also necessary to read the kilometers of the road section (E, F) corresponding to each change of location area. Kilometer readings can also be stored, for example starting from where the road begins and following the road in the direction of measurement using a calibration vehicle and recording the distance while the location is updated. Similarly, the distance recording can be performed automatically if the vehicle situation can be stored as a function of time or also simultaneously as a function of time and place, for example, using a GPS locator. In this case, it is enough to use the signal analyzer to collect the TMSI identifiers of the mobile station connected to the calibration vehicle, and by comparing the time indications for sending the messages, the location in GPS coordinates can be obtained. The points corresponding to the Finnish road network are obtained with great precision from the coordinates when using, for example, a digital map.

The following is a study on the observation made in a means of transport in a case where the vehicle is traveling on a main road in a south to north direction. The example is explained by referring to Figure 2A, the structure of Figure 3 and Figure 4 presenting the content of the database. The transport means moves from a location area 214 to a location area 213. When the system signal analyzer 35i records the location update messages transmitted and received in zone S1 on tape and transmits them to the traffic data server 350 for storage in the database 355 for analysis, the The system will know the address of the subscriber because the signaling time intervals of the connection El to be recorded on the tape are statically determined. Messages arriving from a given observing connection in the system (the PCM time slot to be tracked) indicate directly according to their origin the direction in which the subscriber has traveled relative to the network. When you arrive at the same location update zone from opposite directions, signaling traffic will occur between different cells.

In the example, when the offset occurs between a location area 214 and a location area 213, the clock time of the observed Location Update Request message was 04:45 am and the subscriber's TMSI was A1. The Location Update Complete can then be observed in the same cell and with almost the same clock time, but the TMSI A1 has changed to A7. Changes to the TMSI that occur on the same signaling connection are recorded in their own auxiliary table along with the timestamps. When

ES 2 323 167 T3 the subscriber arrives at the place of change between location zones 213 and 212, that is, in zone S2, the signal analyzer will send to the traffic data server the clock time 05:25 am from the Location update request that has observed the old zone identifier 213 as well as the TMSI A7. Next, the Complete Location Update is observed in the same cell and with almost the same clock time (05:26 am in the example), but the TMSI A7 has changed to A74. When the TMSI A74 reappears in some other part of the network, more information about the movement and speed of the mobile station is again obtained. The Complete Location Update and the Location Update Request with the same TMSI thus form a central part intended to determine the movement of the mobile station.

In the example, the clock time is used in the time calculator, but any other suitable system for measuring time with sufficient precision can be used in a similar way. In this case a timestamp will replace the clock time.

When the first observation is an equal location zone change, said 213 becomes the new location zone and the second observation is a location zone change such that 212 becomes the new location zone, it can know the direction, that is, that the change 214-> 213 corresponds to the point S1 and that 213-> 212 corresponds to the point S2. In this case, it can be seen directly in the kilometers section (E) of the database that the distance of zone S1 from the beginning of the road is seventy kilometers and that the distance of zone S2 is one hundred and forty kilometers, so the distance between zones S1 and S2 is seventy kilometers. In addition, it is possible to calculate the time it takes the vehicle to travel the distance, that is, 40 minutes. Of course, there is no compromising traffic jam on the road, since the average speed obtained by the means of transport is 70 kilometers / 40 minutes = 105 kilometers per hour.

In the above, it is proposed that the zone change points can be found by making measurements separately from the road by observing the exchange of messages between the terminal equipment and the transmitter-receiver base stations and by measuring, for example, the the location of the terminal equipment using GPS location. The procedure is suitable for individual road sections, but is labor intensive when you want to create a partially interconnected network covering a large road network. The network that is required to collect road traffic data can also be collected, for example, by a traffic signal analyzer of a dedicated autonomous control channel SDCCH by collecting measurement results transmitted by the mobile station of the road controller. base station. The terminal equipment transmits the results of the measurements on the power of the signals of the selected cell in relation to the request for the location update and the six adjacent cells that have the highest audibility, the use of which allows a location of the station to be found mobile with sufficient precision to collect road traffic data using, for example, the methods described in published patent US 6,052,598. The following steps are carried out, for example, by comparing the measurement results with the digital road map, extracting a kilometer reading that corresponds to the relevant place on the road and storing the identities of the location area and location in the database. reading kilometers. In this way it is possible to automatically collect points on the network, even on a large road network, by collecting measurement results for a sufficient period of time to allow obtaining the appropriate statistics. By repeating the measurements from time to time the partially interconnected network is updated, so that when the location of the transmitter-receiver base stations changes, statistical errors produced by moving location areas can be eliminated. The analysis of signaling traffic can be carried out by having the terminal equipment move along the road in both directions in a way that corresponds to an analysis carried out separately along the road, that is, using information from the old zone. location, in which specific points corresponding to the place of the road are obtained for traffic moving in each direction.

In the above points, due to explanatory purposes, the present invention is described as an application of a GSM mobile station network but there is no intention that this should be construed as a limitation of the present invention. For example, it is not necessary to use correlatively located location zones if you want to find the time taken to travel a distance, but simply to track an IMSI / TMSI or keep a record of TMSI changes over time, such as minimum, between two location zone boundary crossings that may be located far from each other. Likewise, and in accordance with the independent claims, the invention can be used in various cellular networks or other wireless networks, for which a useful mechanism can be found to observe the messages that depend on each area. For example, to track terminal equipment in a GPRS network, change of address area information can be used. The present invention can also be directly applied to UMTS systems and WLAN systems of various types, not to mention other applicable networks.

References mentioned in this description

The list of references mentioned by the applicant is provided only for a better understanding of the reader and is not part of the document corresponding to the European patent. Although great care has been taken in compiling the references, errors or omissions cannot be ruled out and the EPO disclaims any responsibility for this.

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Patent documentation cited in the description

- US 5933100 A [0006] [0007] - US 6052598 A [0051]

- WO 0123835 A [0006] [0008] [0010]