CZ200196A3 - Localization system of cellular phone sets - Google Patents

Abstract

Mobile phone localization system (1) that communicates with the first base station of the network managed by the operational support center (2). The mobile phone is provided with means for evaluating at least one characteristic position parameter relative to the base station and means for transmitting information relating to that parameter via the first base station to the server (4), which is equipped with means for comparing the information of that parameter to the pre-prepared cartographic processing. this parameter and based on the comparison, estimate the location of the mobile phone.

Description

Technical field

The invention relates to digital cellular radiocommunications with mobile phones, for example according to the GSM (digital cellular telephone standard) standard.

In particular, the invention relates to a system for locating mobile stations that communicate via fixed base stations of a network.

BACKGROUND OF THE INVENTION

In general, this system uses a time inultiplex, which consists of dividing time into predetermined and fixed length frames that are still divided into time intervals. This technique is called "Multiple Time Scheduling Approach" (ARMT) Periodic repetition of a single time interval in each frame forms a physical channel. This structure is used both for the output path from the mobile station to the base station and for the downlink path from the base station to the mobile station. The data exchanged between the mobile station and the base station is transmitted in packets, each of which is located within one time interval. Various logical channels, such as the TCH communication channel and control channels, are multiplexed on the physical channels. For this reason, the time intervals of a given physical channel are divided among several logical channels, creating a new structure, the so-called multi-frame.

The GSM communication protocol is described in "The GMS System for Mobile Communications" by M. Moula and B-B. Pautet, 1992, the contents of which we refer to.

The GSM protocol states that the mobile phone network recognizes in real time the coarse location of the active mobile station in the sense that it knows the reception zone of the communicating mobile station at its current location. The receiving zone is represented by several receiving base stations. If the mobile station leaves a sector serviced by a certain receive zone, it sends a signal of this change to the network. Knowing the current location of the mobile station will allow the network to ensure that it is reachable at any time. In addition, the network knows the global cell identification parameter CG1 for the mobile station connection. A cell is the part of the territory served by the same base station.

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The communicating mobile station transmits a measurement message for the connection at given time intervals. These messages are transmitted on the service radio channel SACCH and allow the network to find at any moment the best receiving station with which the mobile station can establish a connection.

Knowing the time needed to overcome distances between the mobile station and the radio terminal, or TA timing, will allow the mobile station to establish a connection to the base station at a given time so that the base station is ready to receive mobile station outputs without interfering with other mobile station outputs. The TA timing thus reflects the distance traveled by the radio wave between the mobile station and the base station. Increment 1 of this timing corresponds to a distance of approximately 550 m.

The measurement message for the connection sent by the mobile station to the base station contains the RXLEV parameter. This parameter corresponds to the reception level at which the mobile station receives the base station signal with which it communicates and the maximum of the six best neighboring bases. The measurement signal for the connection also includes an RXQUAL parameter that corresponds to the reception quality of the mobile station of the base station signal with which it communicates.

Short Message Service (SMS) allows you to send or receive short text messages on your mobile telephony network. They are transmitted either by the SACCH channel when the mobile station is communicating, or by the TCH / 8 (or SDCCH) signaling channel when the station is operational. The mobile station operator may be equipped with a radio scheduling device which allows the level and quality of reception at a given geographical point to be calculated depending on the geographical location of the base station, neighboring base stations, transmission power, type, frequencies used, etc.

The GSM Phase 2+ 11.11 specifications are well known. and GSM 11.14, specifications regarding the connection of mobile equipment to the subscriber's SIM card. It is also known that a SIM card can request a measurement message for a connection on a mobile device, trigger a short SMS message and store the contents of an incoming short message.

EP-A-0 398 773 discloses a method of geographical location of a mobile station in a time multiplex communication network. In a first step, the mobile station transmits to the first base station a measured shift value of the reception of the synchronization signals from the first and at least the second base station, in the next step the first base station measures the propagation time of the synchronization signal from this base to the mobile station and the shift in BCCH reception, and in addition, on the first base station, the propagation times of the synchronization signal from the second base tv are calculated from the second base tv. · M · · · · · · · · · · · · ·

A station at the mobile station utilizing a stored transmission shift and then calculating the location of the mobile station based on the propagation time and geographical coordinates of the first and second fixed stations.

WO-9635306 discloses a method for determining the location of a mobile station in a cellular network of several base stations. The time difference between base station transmissions as measured by the mobile unit is determined. Based on these time differences, the distance difference between the mobile station and each of the base stations is determined. From this the location of the mobile unit is estimated. The time slice structures of the control channels of at least some base stations within range of the mobile station are synchronized and said mobile station determines the time differences of the characteristic Time slice propagation structure by the control channel of each base station. If the number of base stations detected by the mobile station is too small, the distance between the mobile station and the serving base station is estimated from the time required to communicate with the serving base station.

These various methods make it possible to locate a mobile station without the user's knowledge and are difficult to implement.

SUMMARY OF THE INVENTION

The invention proposes a system in which the location of a mobile station can be performed only on the command of its user or by means of the SIMToolkit function, which allows automatic transmission of short messages only after dialing a special telephone number.

The mobile station location system of the invention does not require modification of the GSM communication protocol.

The location system of the present invention relates to mobile stations that communicate with a first base station of a network that is controlled by an operational support center.

The mobile station is provided with means for evaluating at least one characteristic position parameter relative to the base station, as well as means for transmitting information relating to this parameter via the first base station to the service unit.

The server is equipped with means for comparing the information of this parameter with the pre

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-4 inherited cartographic processing of this parameter and on this basis to deduce an estimate of the location of the mobile phone.

According to the invention, the system comprises means for estimating the distance between the mobile station and the first base station with a degree of inaccuracy Admax depending on the time the wave has passed this distance.

The system of the invention comprises means for estimating the reception levels of the first base station and adjacent stations.

Preferably, the mobile station is provided with means for comparing the reception moments η of the outputs from the other base stations at the reception times r of the inputs from the first base station, and accordingly derives a shift value Δη of the reception moments. In addition, the mobile station is equipped with means by which the first base station transmits to the server the value of each shift Δη, and the server is equipped with means for estimating the distance between the mobile phone and each base station depending on the shift Δη and shift Δε. other bases and moments of outputs e first base.

The system according to the invention comprises means for specifying the location of the mobile phone by evaluating estimates obtained from at least two parameters.

The location can be performed at the command of the mobile station user.

The server is equipped with the means to send the user information regarding the location of the mobile phone. These messages can be voice or text messages.

The transmission of information between the mobile station and the base station preferably takes place on the logical service channel and on the logical communication channel, information relating to said parameter being transmitted to the first base station on the logical communication channel.

The terrain display may be adapted by linear interpolation to the transmission power levels of the various base stations.

The terrain display may be recalculated depending on the evolution of the parameters, which may change the values delivered to the geographic information server, eg depending on the activation or attenuation of frequency jumps on different radio frequencies.

Geographic data can be recalculated depending on the activation or attenuation of the Enhanced Full Rate EFR on different radio frequencies.

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The geographic data can be recalculated depending on the power levels of transmission of different radio terminals, the change of registered card topology, caused eg by building the building, and on the activation of the frequency shift.

The specific position parameter is the NB correlation parameter corresponding to the number of correlations on the BCCH frequency.

The mobile station may be equipped with means for comparing the location data with a preset zone in order to determine a specific tariff, e.g. in the user's home. The location data is stored on the SIM card of the mobile station.

The mobile station may be provided with means to enable the sending of tariff-related data via the short message service.

According to the invention, the mobile station transmits tariff data if requested or received near the preset zone when the mobile station enters or exits the communication zone.

According to another embodiment, the mobile station is provided with means for sending a move message to the fixed network if the mobile station is in a preset zone requiring a change in call routing so that each incoming call is recorded at one or more fixed stations and at the mobile station.

In such a system, the mobile station may be used for multiple options, e.g., to send an emergency signal, to provide information about the location of the user. The user may thus be connected to a database having geographic information suitable for guiding the user in an emergency; when hiking, including comments about the surrounding area. Establishing a connection to the database can be done using a special phone number, which remains fixed for any location. Any language can be chosen for communication, either automatically based on the information stored on the local server or at the user's choice, or associated with a phone number.

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Overview of the drawings

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail with reference to the drawing, in which: FIG. Fig. 2 - a variant of Fig. 1; Fig. 3 - a diagram of capturing the number of radio wave correlations in a geographic information server; FIG. 4 is a schematic of a specific time profile collection.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, mobile equipment means a mobile phone without a SIM card inserted. Mobile equipment can only send an emergency call.

The Subscriber Identity Module (SIM) function is to identify the subscriber of the mobile network.

A mobile station is a set of mobile equipment and a SIM card. In this arrangement, it can send or receive telephone calls.

The serving logic channel transmits every information necessary for the mobile network to function properly: sending and receiving messages, Handovers ...

The service channel uses various types of physical channels, such as BCCH or SDCCH.

The information transmitted on the logical service channel is managed by the mobile telephony operator's infrastructure.

Conversely, a logical communication channel carries information intended for subscriber communication. The radio logical communication channel utilizes one or more physical channels, such as TCH, SDCCH (TCH / 8) channels or half of the TCH channel if the telephony operator has introduced the optional half power service or Haif rate. It should be noted that the physical SDCCH (TCH / 8) can transmit service information or communication information. The information transmitted on the communication channel is not intended for the mobile telephony operator and is subject to billing. This information may be in the form of audio or "data" transmitted by SMS or USSD -Unstructured Supplementary Services Data, or GPRS - Global Packet Radio Switch.

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-ΊGPRS - Global Packet Radio Switch is a radio communication protocol that enables IP data transmission - Internet Protocol - on the GMS telephony infrastructure.

If we refer to the communication layers defined by OSI, then GPRS is at the interface of the IP communication layer and the physical layer.

GPRS allows the mobile station to communicate according to IP format: access to Internet servers, sending + receiving electronic messages, ..

Stable / mobile convergence is understood to mean all techniques that make it possible to approach and possibly mix the fixed and mobile telephony subscribers.

This convergence offers the benefits of fixed telephony in the residential area, especially in terms of voice quality and high performance.

Other advantages of stable / mobile convergence are uniform invoicing, price difference according to the place of call, eventual use of the same telephone input.

As shown in Fig. 1, the mobile telephony network comprises several base station systems I (not shown), each communicating with a plurality of mobile stations (not shown). Each system i is connected to an operational support center 2. Each operational support center 2 manages several systems I. operational support centers 2 are connected to a network management center 3. the network management center is connected to a geographic information server 4, the equipment of which enables information exchange a scheduling device 5 and a switching center 6, interfaced with a branch telephone network (not shown).

FIG. 2 shows another variant in which the operational support centers 2 are directly connected to the geographic information server 4.

In order for the geographic information server 4 to calculate the location of the mobile station, it is necessary for that station to send a certain number of information to the server. The mobile station sends location-related parameters to the server 4 via a logical communication channel. The geographic information server 4 receives these messages arriving on the voice channel in the form of short text messages or in the form of IP (if the information is leaving the mobile station in GPRS format).

The service information that the mobile station transmits to the geographic information server 4 are parameters to help determine the location:

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-Global cell identifier CGI serving cell, BSIC binoma, BCCH cells adjacent to the serving cell. The mobile station sends this information through all the BCCHs it is able to establish and which may be greater than 6, information regarding the RXLEV reception levels of all said cells, information regarding the reception quality of the RXQUAL serving cell and preferably also neighboring cells, the moment difference attribute receiving the D1R of all the above cells, the NB correlation attribute indicating the number of BCCH frequencies of said cells, the time difference of receiving the DTR sync signals SCH from each said cell, and the attribute related to the time elapsed since the measurement began. station.

Global CGI cell identification parameters and BSIC and BCCH binomas are most useful for locating a mobile station. These parameters are used to identify the cells involved in the location of the mobile station. They are already known and processed by the mobile station and can therefore be easily transmitted to the geographic information server 4.

For special cases, in particular for emergency calls, it is possible to modify the station to provide service information belonging to cells of another mobile telephony network. GSM recommendation 05.08 ETS 300578 states that the mobile station must be able to search all GSM frequencies to capture BCCH frequencies and calculate their reception power. In this case, the geographic information server 4 knows the location of the different networks and thus also knows the cells that are adjacent to the cell.

A report containing the information necessary for geo-location will be referred to in the following as the term "measurement for location".

The mobile station has already performed calculations of the RXLEV parameter on the carrier frequency (RXLEVFULL-SERVING-CELL and RXLEV-SUB-SERVING-CELL) and the BCCH adjacent cell frequencies (RXLEV-NCELL) and the carrier frequency RXQUAL parameter (RXQUAL-FULLSERV1NG-CELL and RXQUAL -SERVING-CELL).

The mobile station may advantageously perform the calculation of the RXQUAL parameter on the BCCH frequencies of neighboring cells.

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To unify the measurements sent to the geographic information server 4, it may be decided to calculate the RXLEV and RXQUAL service frequency parameters not on the whole (ear on the chiosia) TUMA, but only on the inulliiánic BCCH. However, in the RXLEV and RXQUAL paiameters there are inaccuracies at different base stations, which are mainly associated with changes and interference with other radio waves.

The TA timing parameter is calculated as follows. The mobile station synchronizes on the BCCH frequency of the serving radio terminal via the FCCH and SCH channels. In the case of multi-way traffic, which is particularly prevalent in an urban environment, the mobile station synchronizes to the strongest received signal. Once it initiates communication, the base station system 1 estimates the distance traveled by the radio wave from the mobile station to the serving base station and transmits the TA parameter to the mobile station.

In the case of multi-way transmission, the mobile station performs several correlations on the same signal. For the purpose of synchronization, it searches for the signal that corresponds to the best path in terms of performance and reception quality and receives this signal at time T2. The mobile station also knows the time T1 at which the first signal correlation was received. This makes it possible to define a new parameter called the distance of the direct DCD path between the mobile station and its service base: DCD = D (TA) - cx (T2-T1), D (TA ) is the distance calculated on the basis of the time advance indication TA transmitted from the operating base and c is the speed of light.

The DCD parameter represents the actual distance between the serving base station and the mobile station better than TA. The performance of the first received correlation of the signal can be reduced due to various obstacles, such as trees located in the wave propagation space. The strongest correlation can also come after rebounding from other obstacles, such as the walls of houses.

It is also possible to take advantage of the difference in the time of reception - DIR - of signals from different base stations (see recommendation GSM 05.10 - phase 2+). To eliminate the inaccuracies associated with multicast transmission, the mobile station will be able to calculate a reception time difference corresponding to the shortest propagation time of each radio wave rather than the time it needs to receive the highest power signal. This will allow the mobile station to calculate the DIR parameter for each of the neighboring base stations.

If the radio terminals are synchronized or the geographic information server 4 knows the RTD deviation between different base stations, then this server will be able to calculate the distance to the respective base station. However, this DIR parameter allows for ·· φ

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• vést Perform accurate localization calculations only if the bases are accurately synchronized or the RTD variation is known and does not change over time.

The mobile station, when listening in the mobile telephony network, synchronizes with each of the BCCH frequencies of the serving cell and neighboring cells. For this purpose, it is synchronized to SCHCH synchronization signals of the BCCH. Between the base and the mobile station the radio wave spreads in different ways. This phenomenon is called multicast transmission. In this case, the mobile station correlates with the best path in terms of performance and quality, not the shortest path. After calculating the number of BCCH frequency correlations received by the mobile station, the station can calculate the NB-correlation parameter value for each of the received BCCH frequencies and transmit it in the " calculation for location " message. Of course, we can assume a filter to eliminate correlations that correspond only to very average reception.

The mobile station may make an estimate of its relocation and possibly an approximate relocation rate. The measurement of the DTR reception time difference is measured by the reception time difference of the same SCH multi channel BCCH signal. The BCCH multi-frame contains five SCH signals. Within the ultra frame, the SCH signal is transmitted every 10x8 period of the BP signal or 11x8 period at the end of the multi-frame BCCH. If the BP signal period lasts exactly 15/26 ms, then the non-relocating mobile station receives each SCH signal every (10x8x15) / 26 ms and once from five cycles each (1 x 8x15) / 26 ms. The BCCH multi-frame is transmitted cyclically. The length of its transmission is: 51x8x15 / 26 = 235.38 ms. If t1 is the moment when the mobile station receives the SCH signal of the BCCH, and t2 the time of receiving the same SCH signal of the BCCH transmitted eg five cycles later, then the time difference of the DTR reception is: DTR = t2 -tl-t when t = 5x51x8x15 / 26 ~ 1, 17671 sec. Thus, the minimum displacement rate will be the maximum value of the DTR parameter calculated at each of the received BCCH frequencies. In the event that the BCCH frequency was not received continuously on five multi-frames, the mobile station shall indicate this in the "measurement for location" message.

There are several options for sending a “measurement for location” message to the geographic information server 4, either by automatic activation after entering the server telephone number or manually activated by the subscriber. The telephone number of the geographic information server 4 may be stored on the SIM card of the subscriber's mobile station or in the mobile station software. The subscriber may register the telephone numbers of the geographic information servers that are authorized to locate it. As soon as the geographic information server telephone number is entered, the mobile station starts the calculation of the above parameters. The mobile station can also transmit ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft ft

- lina server of geographical information values of reception level of different frequencies BCCH cells of mobile network captured by mobile station before making contact and thus speed up the calculation of location.

There are various options regarding the frequency of sending a "measurement for location" message by the mobile station. The mobile station can only transmit this message under appropriate conditions, eg if the DTD parameter has a significant value.

The mobile station may send a "measurement for location" message upon receipt of an information request from the geographic information server in the form of a short SMS or GPRS. The frequency of output of the “measurement for localization” messages can be preset for, for example, 30 seconds. The frequency of output of the "measurement for localization" message may be specified in a message sent by the geographic information server.

These different options may advantageously be combined. For example, a mobile station may transmit a "location measurement" immediately after dialing the phone number of the geographic information server or while moving the mobile station, or after receiving a location request message. This may be particularly useful when the geographic information server fails to estimate the location of the mobile station, which may be the case with erroneous or incomplete data.

The geographic information server may need measurements associated with the base station. It sends an SMS or GPRS “specific measurement request” message specifying BS1C, BCCH of the base station. The mobile station then sends a "measurement for input" message related to the base specified in the "specific measurement request" message. These measurements include a BSIC member, base station BCCH, RXLEV, RXQUAL, NB correlation, DTR, NB cycle and, optionally, distance related parameters if the base station is serving or if the mobile station is able to calculate the DIR parameter relative to the serving cell. The data transmitted between the mobile station and the radio input of the base station is encrypted, which ensures some confidentiality of the communication.

However, this data is not sufficient to calculate the location of the mobile station since the location information of the base stations is not transmitted by the network, but is known to the geographic information server.

The mobile station will only send a “localization measurement” message in the following cases: after dialing a special geographic information server phone number, after receiving an “authorized” message corresponding to the location request, »

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- 12 periodically to the server identified by the mobile station.

In both of the last cases, the "tracking for localization" message is managed by the card

Subscriber SIM Some subscribers may therefore assume that the mobile station is periodically identified by the location server. An ad hoc SIM Toolkit has been developed for this case and the SIM cardholder should be notified that a switched-on mobile station may be localized.

For example, a list of phone numbers of different geographic information servers may be registered on the SIM card or in the equipment of the mobile station itself.

To keep the data confidential, the user's SIM card may be provided with an encryption key K that is the same or different from the encryption key according to the GSM recommendation. The mobile station checks the identity of the geographic information server. When the connection is established, the mobile station sends a RAND code to the server. The server knows the K key of the subscriber and calculates the SRES code that it sends in the "localization information request" message. Upon receiving this message, the mobile station checks whether the SRES code matches the code it calculated itself. If so, the mobile station will send a “localization calculation” message. Otherwise, the mobile station will not send this message and notify the subscriber that an incomplete location attempt has been made.

Also, the mobile station can only transmit the BSIC and BCCH serving cells instead of directing the positioning messages. The geographic information server, which, after capturing the service cell zone identification zone LAI, queried the VLR database covering the zone from which the call was sent recognizes the service cell CG1 and all members

BSIC, BCCH of neighboring cells and can send them to the mobile station. The mobile station checks the accuracy of the transmitted information.

The Geographical Information Server 4 is an expert system that estimates the most likely location or zone of occurrence of a mobile station by correlating between the values of the parameters sent to it and the values recorded in its database. The parameters entered in the geographic information server database are associated with fixed geographic points. The parameters that the geographic information server can use to estimate the location of a mobile station are reception level, reception quality, distance, various paths the radio wave travels between the base station and the point. mobile station and cell time communication profile.

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- 13 The RXLEV corresponds to the reception level between serving or neighboring base stations and the mobile station. The mobile station knows the received RXLEV parameter, i.e. the level of reception it receives from the serving or neighboring base station. The RXLEV parameter can also be sent in many variations to a mobile station that does not move away from a given location, which is essentially due to the attenuation phenomenon of radio waves. A wave of a given frequency is often the result of several signals of different phases.

The reception quality parameter corresponds to the reception quality level between the serving or neighboring base stations and the mobile station. Also, this reception quality parameter may be affected by different variations that occur due to radio frequency attenuation phenomena or interference between different signals of the same frequency when other base stations use the same frequency. The more communications take place at a given moment, the lower the quality of communications.

Frequency shift allows to improve reception quality by changing the pseudo-random frequencies used except the BCCH frequency. This change has to be taken into account when making land maps.

The time spacing between the mobile station and its serving base station is estimated either by the TA advance timing or by the DCD direct link length. Alternatively, the difference with neighboring bases can be estimated using the DIR reception time difference parameter if the bases are synchronized or if the geographic information server knows the variation of the RTD output of each base station. In this case, the geographic information server SIG can calculate the difference parameter found in

ODT = DIR + RDT. The time spacing with neighboring cells can be calculated according to the formula: D = Do + Cx (OTD) when Do = difference calculated by TA or Do = DCD, and C: light speed.

For each geographical point and each cell, an NB-Collation parameter is assigned corresponding to the number of BCCH frequency correlations between the radio terminal and the mobile station. This value, which is captured in the geographic information server database, may be the result of a calculation made by the scheduling means 5, which may optionally be supplemented by physical measurements (see Fig. 3). In the case of values obtained from the scheduling means, the success of the calculated values depends on the quality of the digitized topology, which, however, can be improved by comparing physical and calculated measurements.

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- 14The value of the RXLEV parameter, and in particular the RXQUAL parameter for a given call, depends on the number of messages sent simultaneously to the serving station or its adjacent station. It is possible to process the time profile of the communication depending on the location, time and day. Using statistics processed by the various operational support centers 2, network operators can compile a time traffic profile at various locations managed by the geographic information server 4. For example, traffic at base stations covering a football stadium will be most significant on the day of the match.

The time profile system 7 (FIG. 4) may be coupled to the geographic information server to define a time profile related to the simultaneous operation at each base station. The time profile system can draw information from operational support center statistics or network management centers, or from physical measurement data. The time profile for each base station depends on the type of day (business, holiday), hour, significant days or special events.

The geographic information server receives the calls it sends and processes the location parameters associated with the call.

Using the interface with Operational Support Centers 2 or Network Management Centers 3, the geographic information server knows the serving cell CGI parameter and binomial compliance (BS1C, BCCH) of all cells adjacent to the serving cell with their respective CGI parameters, the exact geographical location of each base station, in three dimensions taking into account the antenna height of the station, the transmission power of each network station, the directional frequency: GSM 900, GSM Extendet, DCS (or GSM) 1800, PCS 1900, or other frequency type, parameter indicating whether or not not the frequency shift and EFR (Enhanced Full Rate) at each base station, the exact geographic location of each modeled fixed point in three dimensions. The “Enhanced Full Rate” EFR technique allows you to improve transmission quality with an improved coding converter that is standardized. It should be noted that the EFR is activated for each call only if the mobile station supports this version. EFR behaves in the same way as frequency shifting: its activation optimizes speech quality.

Because of its connection to a planning device or physical measurements, the geographic information server knows the estimated reception levels and quality of each of the BCCH frequencies received by the model geographic point and the number of paths the radio wave travels between the base station and the digitized point. Income, Quality, Interfaces · 44 · *

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The frequency and estimated number of radio wave paths are recorded in the geographic information server before the mobile station prompt.

The geographic information server uses values calculated at different times to estimate it. However, it must take into account operational requirements, in particular for some network-dependent radio transmission parameters, in particular the BSIC binom, BCCH and CG1 identifier, the power level of each base station and the frequency hop activation.

Due to its connection with the network operator, preferably via the standardized interface Q3, the geographic information server is informed in real time of any changes to its parameters so that it can use them to estimate the location of the mobile station. The geographic information server is also informed of the operating status of the base stations, in particular of possible failures. In the event of a change in the transmission power of one of these stations, the server can make the first approximation, assuming that the relationship between the reception power at a given geographical point and the transmission power of that base is maintained.

Upon receipt of the "measurement for location" message, the geographic information server calculates the CG1 of all cells that are invited to measure by the CGT serving cell and the BSIC, BCCH members of all adjacent cells.

Then, the server estimates the most likely mobile station location zone using distance, reception level, reception quality level, and the number of correlations between the mobile station and various neighboring base stations. This estimate is made by comparing it with preset values according to the rules set by the expert system. At maximum load, a large amount of information arrives at the geographic information server. However, it should be taken into account that some of this information may be incorrect. The expert system is able to eliminate disparate parameters for localization calculation using the values of other parameters.

Upon receipt of the parameters, the polling process proceeds according to the reasoning and deduction rules to determine the location of the mobile station. Estimating the location of the mobile station by the geographic information server will be different when the station is moving and not moving. station, increased frequency of the "measurement for localization" message output, DTR parameter and more

If the mobile station remains in place, the geographic information server has time to calculate its location more accurately and can use all the parameters at its disposal to do so.

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- 16The geographic information server in response to the challenge shall have a set of values: (RXLEX) a set of geographical points in the field corresponding to the RXLEV values of the relevant base stations, (RXQUAL) a set of geographical points in the field corresponding to the RXQUAL distance to the serving base station.

The geographic information server performs evaluation according to the reasoning rules, the following of which are given as possible examples;

Rule 1:

If a point can be defined by intersecting the above three sets of values, then the mobile station has been located.

Rule 2:

If the intersection of (RXLEV) and (RXQUAL) results in more points and if a distance estimate using TA advance has been found to have a set of points more distant from the serving base station than in the previous measurement, then TA advance lead certainly corresponds to multiple transmission. In this case, the TA parameter is not taken into account.

Rule 3;

If the geographic information server receives a distance parameter that is the distance of the direct DCD path, then this estimate is more reliable than the TA time estimate. The geographic information server first looks for points that match DCD parameters, and then correlates them with the sbody obtained using the RXLEV and RXQUAL parameters.

Rule 4

If the set of geographic points found is close to the base station and is not included in the "Measurement for location" message, then the geographic information server checks whether the base station is active and performs this check through a connection to the operations support or network management center. station inactive, then the location of the mobile station was found. Otherwise, the geographic information server sends a "Specific Measurement Request" message to the mobile station specifying: 0 0 * 0 0 0 * «00 ** 00 0 · «0 ·« 00 t

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The BSJC, BCCH of the respective base station. The mobile station sends a “measurement for location” message to the station. The geographic information server then determines whether the calculations are correct.

When the mobile station is in motion, the geographic information server does not have enough time to use all of its available parameters. The server estimates the DPT shift pointer, which is the maximum value of the DTR reception time differences, allowing it to estimate the minimum station speed. To first estimate the location of the mobile station, the server uses the identifiers, CGI and BS1C, the BCCH of the base stations received by the mobile station, and the distance to the serving station.

If the geographic information server does not receive any additional location measurement data, it starts performing operations just as it does with a stationary mobile station. Otherwise, the server estimates the location of the mobile station based on the differences between the values it received.

The parameters used will be the serving base station CGT identifier, the neighbor station identifier (calculated from their BS1C, BCCH), the distance to the serving base station, and the geographic information server map entry. Since the mobile station can only move quickly along road and rail routes, the geographic information server includes a vector map entry to run the location estimation along different axes. The geographic information server uses the rules of expert systems.

The following three rules are also given as an example:

Rule 1

In the case of handover, the geographic information server can estimate the location of the mobile station by examining the terrain display, using the vector display, the time interval between two parameter value outputs, and the DPT parameter value. If the DPT parameter allows the mobile station speed to be estimated at 40 km / h, the time interval between the two measurement outputs is 20 seconds, the arc arcs indicating the distance interval between the mobile station and the two base stations at the time of both output values are identical and where the two arcs of the circle are identical, then it is almost certain that the mobile station is located at this point.

Rule 2:

Based on the estimation of the mobile station's speed using the DPT parameter, the north of the geographic information of the road or rail route on which the mobile station can move will be recognized. ··············· · · ·

-18vat. For example, if the estimated mobile station speed is of the order of 250 km / h, then the subscriber is most likely to be on a train whose route the geographic information server knows.

Rule 3

If no value is sent over a longer period of time, e.g., 15 seconds, the geographic information server initiates a stationary station location operation.

This mobile phone location system can be used to distribute geographic information associated with the exact location from which the call was sent. This information is distributed with the permission of the geographic information publishers and is only available to subscribers to the mobile telephony network or to persons purchasing such a service. Each phone number can match a distribution language, and the phone number can be the same for all networks. Geographic information can be of various kinds, eg tourist, cultural, business, meteorological, culinary, etc. If, according to the geographic information server, there might be any confusion about local conditions, it can provide comments tailored to specific locations of user's choice or send to a mobile station "Location information request" message.

This localization system can be used for guidance or assistance operations. A zone of probable location of the mobile station can be indicated on the digital map of the geographic information server. This allows the operator to direct or subscribe to a subscriber or locate a call for help. The calculation of the position relative to the base stations to be performed in conjunction with the bases of other mobile telephony networks.

The telephony operator can also use this localization system to offer a "stable / mobile" convergence service; either apply a specific tariff for each call posted near the subscriber's home or converge the calls mobile and stable.

In the first case, the mobile station sends a "metering measurement" message to the tariff center via a logical communication channel. The “Localization Measurement” message contains the date and time of the start of the communication, the duration, and the subscriber identifier. If it is not possible to send the message, for example because of a congested network, the message is stored and transmitted at the appropriate time.

During the conversation, the mobile station will only send a "metering measurement" message in three cases; incoming or outgoing call made in the residence zone, exit of the mobile station during the conversation from the residence zone, entry of the mobile station into the subscriber's residence zone during the conversation.

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- 19 A mobile station that enters the subscriber's residence in the case of the Stabia / Mobile Convergence Service sends a "transition to stable" message to the switching center via the radio logical communication channel. From this point on, the network operating system adjusts the challenge paths so that only one of the stations operates: each challenge can be sent from a landline or a subscriber's mobile station, and each incoming call is recorded on the subscriber's fixed line and mobile station. The mobile station does not need to communicate to transmit a "go to stable" message, as the GSM standard assumes that each mobile station, in its active state, performs a free or "idle" reception measurement

In families where there are several mobile phones and one landline, convergence can be made to that one subscriber station.

Upon leaving the home, the mobile station will send a message to / from the switching center, "

Transmission to “stable” messages can be manually interrupted.

There are two different ways to activate stable / mobile convergence at the mobile station.

The first solution is as follows: when the mobile station processor is located at the home, it may prompt the server to send a "measurement for localization" message. The server receives the data and compares it with the values in its database. If the data is coherent, the server sends a message to the mobile station notifying it that the data sent corresponds to the place of residence. The server also passes it a BSIC / BCCH member and CGI cells of neighboring cells. As foreseen in the GMS Technical Specifications 11,11 and 11,14, the mobile station has stored on the subscriber's SIM card a global cell identifier of CGI cells that the mobile station of the subscriber captures at their residence, their BSIC / BCCH and their calculated reception level.

The second solution is to provide the mobile server with global CGI cell identifiers that the subscriber's mobile station intercepts at their residence, their BSIC / BCCH, and the calculated level of their reception, via the logical communication channels to the mobile station. As foreseen in the GMS technical specifications 11,11 and 11,14, the mobile station stores the values sent by the information server on the subscriber's SIM card.

If the frequency plan on the mobile network is changed, there will be a change in the match between the CGI global cell identifier and its BSIC / BCCH. In this case, the information server sends the values specified in the previous paragraph before changing the frequency plan, and the subscriber's SIM card then contains two sets of calculations that can be used to calculate if the attendance is calculated. · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · «·

-20 participant in the place of residence. These values will be calculated by the operator's radio scheduling means.

Likewise, the information server will send new levels of reception in real-time if there is a change in the transmission power in the radio direction covering the subscriber's home. Calculations and estimation of the possibility of sending a "metering measurement" on Stable ”, the mobile station has a global CGI cell identifier, its BSIC / BCCH, and an appropriate reception level for each cell located in the subscriber's residence area. It is important that the SIM card contains all the global CGI cell identifiers, since the cell carrying the communication sent from the subscriber's home will still not be the same. In fact, the mobile station only knows the global identifier of the cell carrying the communication and only knows the relative identifier of neighboring cells, i. their BSIC / BCCH.

The mobile station's SIM card software calculates whether the station is in your home area. The operation consists of: verifying that the global CGI cell carrying the current call is registered on the SIM card. If this step agrees, it compares the reception level values calculated by the mobile ambulance to the values written on the card for the serving cell and its adjacent cells identified by their BSIC / BCCH. The SIM card software, of course, takes into account the inaccuracies described above. If more than one set of values is written on the card, the device compares all values.

Outside the perimeter of the mobile station's residence, it does not transmit any stable / mobile convergence message. The subscriber in the mobile network knows that it will be localized "without his knowledge" only in the district of his / her home.

Claims (11)

PATENT CLAIMS A system for locating mobile phones that communicate with a first base station of a network managed by an operational support center, when such a mobile phone is equipped with means for evaluating at least one characteristic location parameter relative to the base station and means for transmitting information relating thereto via said first base station. a station to a server equipped with means for comparing the information of this parameter with a pre-prepared cartographic processing of this parameter and based on the comparison draws an estimate of the location of the mobile phone, characterized in that the information a logical communication channel, the information relating to said parameter being transmitted to the first base station via a logical communication channel, System according to any one of the preceding claims, characterized in that it comprises means for estimating the distance between the mobile phone and the first base station with a degree of inaccuracy Adb _m as a function of the time the wave crosses this distance. System according to any one of the preceding claims, characterized in that it comprises means for estimating the reception levels of the outputs of the first base station and the neighboring base stations. System according to any one of the preceding claims, characterized in that the mobile phone is equipped with means for comparing the reception times η of the outputs from the other base stations at the reception times r of the inputs from the first base station. further provided with means for transmitting the value of each shift Δη via the first base station to the server, and that the server is provided with means for estimating the distance between the mobile phone and each other base station depending on the shift Δη and shift Δβί between output e of the first base station. • 4 «4« »· 4 • 4 4 4 4 *« 44 4 • · 4 4 · φ 4 4 • 444 4444 44 4 · 4 · 44 ··· -225. System according to any one of the preceding claims, characterized in that it comprises means for refining the location of the mobile phone by reviewing location estimates obtained from at least two parameters. System according to any one of the preceding claims, characterized in that the localization is carried out at the command of the mobile phone user. System according to any one of the preceding claims, characterized in that the server is provided with means for sending information to the user at the location of the mobile phone. System according to any one of the preceding claims, characterized in that the cartographic processing is adapted to the transmit power levels of the different base stations by the linear interpolation method. System according to any one of the preceding claims, characterized in that the cartographic processing is recalculated depending on the development of the parameters which can change the values coming to the geographic information server. System according to any one of the preceding claims, characterized in that the mobile phone is provided with means for comparing the location data with a preset zone with respect to a specific rate setting, wherein the location data is written on the SIM card of the mobile phone. System according to claim 10, characterized in that the mobile phone is equipped with means for transmitting the tariff data via a logical communication channel. System according to claim 11, characterized in that the mobile phone sends the tariff data in the case of a command or has received a prompt near the pre-registered zone and when entering or exiting the zone during communication. · · Ř · ř · · · · · »» »» »» »» »» »·» »· · · · -2313. System according to claims 10 to 12, characterized in that the mobile phone is provided with means for sending a fixed network transition message when the mobile phone is located in a pre-registered zone and thus requires a change in the routing of the calls such that each incoming call is recorded on one or more fixed stations and on the mobile phone.