EP1742190B1 - Method and system for obtaining information on traffic flow - Google Patents

Abstract

Method for obtaining traffic-flow data in which position data and identification of mobile terminal (MS) in at least one vehicle is obtained. The position data is obtained from the signaling data during entry of the respective vehicle into a new cell-zone (LA;LA B) with establishing of the identification of the first cell (Z B1) in the new cell zone. The signalling data is taken off at the interface (A) between the RF switching station (MSC) and the associated base station controllers (BSC). An independent claim is also included for a system for obtaining traffic flow information.

Description

The invention relates to a method and a system for obtaining traffic flow information according to the introductory parts of the independent claims.

Such extraction of traffic flow information is over WO 03/041031 A1 known. However, the known technique is based on VLR data (VLR - Visitor Location Register) and LAI information (LAI - Location Area Identity), wherein the position of a subscriber or terminal are detected only with the accuracy of a cell area (LA) can. Mentioned (but not described in detail) is further that mobile data and parameters can be used between base station controllers and mobile switching centers, but only the use of the respective cell area identity is explained. A similar doctrine is also off DE10225033 refer to.

In the US 2003/0078055 A1 A technique is described which is based on active call data (signaling in connection setup or down, etc.) to detect traffic flows. This system has the disadvantage that, among other things, only in use located mobile devices can be detected, but not only turned on, but not actively used terminals. It is therefore, obviously, in order to improve the accuracy, also proposed to use coordinates from other positioning methods, for example, from GPS, for determining the position of a subscriber or mobile terminal.

From the DE 100 32 800 A1 a method for detecting traffic situation data is known, wherein a cellular mobile radio network is used, which contains a plurality of uniquely identified base stations and thus cells that cover the considered traffic route network; in this traffic network are vehicles in which the mobile network belonging mobile devices are available. If a vehicle with a mobile terminal located therein is considered, the travel of this vehicle is tracked on the basis of the identification of the base stations or cells, whereby the route in the traffic route network is determined via these cell identifications. However, one problem with this is that only actively used mobile terminals are detected via the base stations, ie mobile phones that are not only switched on but also also actively participate in communication with another participant. This does not include those mobile devices that are on but are not currently being actively used. Research has shown, however, that only a fraction of mobile terminals in vehicles, namely about 2-5%, are actively in operation; but only very vague statements about the traffic situation can be made.

A further disadvantage is that in the area of the base stations or the base stations associated A _to interfaces are not standardized electronic devices, but depending on the manufacturer different standards having facilities in use. As a result, there are problems with the data acquisition in this area of the A _bis interfaces, since apart from the fact that the respective approval of the network operator is required, also adaptations of the probes depending on the type of device are required.

A particularly serious disadvantage is also that there are a plurality of base stations and, accordingly, the same number of A _to connections are present, which must be monitored by means of probes. This not only means that a corresponding large number of probes must be installed for data acquisition, but also that an extremely large amount of data has to be acquired and probed, whereby it must also be taken into account that the entire signaling traffic is transmitted via the A _bis interfaces is unwound and an extremely large number must be processed by signaling accordingly se per a _to compound.

Furthermore, it is disadvantageous that, as studies have shown, an average call duration is approximately two minutes, which corresponds to a distance of 4 km in the case of a vehicle moving on a highway at a speed of 120 km / h. Accordingly, an active participant, ie an active mobile terminal, on average only 4 km long (eg on a highway) to be followed, which is the evaluation and extraction of information about a traffic event in larger traffic network areas, such as on a highway a length of 50 or 100 km, additionally difficult.

The above disadvantages are equally applicable to the method and system for determining the travel time of a mobile user terminal according to the DE 101 49 943 A1 to, since there, too, the determination of the positions of the terminal equipment (ie terminals) is limited to actively used terminal equipment, the information required for this purpose on the base stations, thus again on the A _to connections, are obtained.

According to the DE 103 34 140 A In the case of the determination of traffic data described therein, a cellular position determination also takes place, in which the change of an active terminal from one mobile radio cell to the next is detected, and wherein in the transition area a road section is assigned, so that a virtual counting point for the one cell in the other changing vehicles (but only for those vehicles in which an actively operated mobile phone is located) is created. These counts are then used to determine the traffic volume, whereby it is also envisaged to exclude public means of transport (ie more accurately located in public means of transport active terminals) from this traffic count by filtering out the corresponding data.

Also in the article of Jean-Gabriel Remy, "Computing Messages: The STRIP project", 2001 IEEE Intelligent Transportation Systems Conference Proceedings - Oakland (CA), USA - August 25-29, 2001, pages 6-9 , a system for estimating travel times is addressed on the basis of radiotelephone signaling data, again based in particular on active, that is involved in a conversation radiotelephone devices. Although it is also referred to merely switched, non-active terminals, but only with the note that the position determination here, although possible in principle, would be so cumbersome. On the other hand, it is found that 5% of the vehicles (namely, apparently those with active mobile telephones) would be sufficient to estimate driving times. It is also emphasized that the recording of position data is the load on the radio network not allowed to influence. Another disadvantage, however, is that in the case of the specifically described embodiment in the mobile telephone network at the A _bis interfaces (ie the interfaces between the base stations and the associated base station controllers), the data is to be recorded, which is the disadvantage of the huge amounts of data to be processed. the need for the many probes, the manufacturer-dependent interface devices and thus the adaptation of the probes to the latter brings.

In the DE 102 37 563 A1 Finally, a technique for determining location data of moving objects is described, in which the location data are determined either by means of GPS and forwarded by means of a mobile terminal or by the base stations of mobile radio cells to an exchange. Here, too, at least the disadvantages explained above result.

It is an object of the invention to provide a method and a system as stated above, from the outset, less data for the extraction by traffic flow information are to be taken, further with a much smaller number of probes Auslangen can be found and also the installation of necessary facilities is simplified. Furthermore, in the technique according to the invention, all subscribers who are traveling with a mobile terminal switched on are to be detected without an active call connection being necessary for the acquisition, i. without the mobile terminal having to be actively used.

The invention is defined by the claims and is based on the recognition that position data can be used for obtaining the position data and for the derivation of the traffic flow information, not only between base stations and base station controllers, but also between the latter and the be transmitted to the central mobile switching centers. These position data are update data, in the case of a GSM network in particular the "Location Updates", in the case of GPRS the "Routing Area Updates" and in the case of a UMTS network the "Location / Routing / UTRAN Area Updates". This update data are in each case when changing from a cell area (in GSM networks "Location Area", in GPRS "Routing Area", and UMTS called "UTRAN Area") in a subsequent cell area available, ie in such a change of cells Area, the aforementioned localization update takes place, wherein each of the identification of the first cell of the new cell area is transmitted. This is exploited in the technique according to the invention, so that an exact position - with the resolution of a cell - is made possible on entry into the respective new cell area without an active call signaling being necessary for this purpose.

Accordingly, the invention provides a method and a system according to the appended independent claims in order to achieve the above object. Advantageous embodiments and further developments are specified in the respective dependent claims.

According to the invention is thus at the one or more central mobile switching centers (MSC - Mobile Switching Center), thus at the A-interface in the case of a GSM network or the Gb interface in the GPRS case and at the Iu interface in the case of UMTS network, the acquisition of update data made. By detecting the position of the respective vehicle with mobile terminal turned on with cell accuracy, even if only entering a new cell area, the technique according to the invention achieves an accuracy of cell size positioning comparable to prior art systems. Compared to the prior art, however, the considerable advantage is achieved that a much smaller amount of data has to be captured and processed, and that also fewer probes have to be installed in order to acquire the desired signaling data, the reduction corresponding to the fact that instead The cells are now monitored each containing a plurality of cell cell areas (or more precisely, the connections from their base station controllers to the associated central mobile switching center). It is therefore not the number of cells themselves, but the number of cell ranges for the number of probes that is decisive, and moreover, it only comes into play that then the respective ones Position update data (upon entry into the respective new cell area) must be extracted and supplied to the processing for the purpose of obtaining the traffic flow information. Another advantage is that in the area of the A-interface (or Gb or Iu interface) regularly standardized facilities exist, so that no adaptations are necessary when mounting the probes.

Thus, the invention provides a considerable apparatus and procedural simplification compared to the prior art, without a loss in the accuracy of the positioning would have to be accepted; Another advantage is that now, unlike the prior art systems, only switched-on, non-actively used mobile phones (mobile terminals) are taken into account, so that the reliability of the calculated traffic flow information is substantially increased.

Each recorded event, ie the respective position data with terminal identification and identification of the respective first cell of the new cell area, is provided with a time stamp, as is known per se, and the geographical coordinates are assigned as known per se. The time for the timestamp data is conveniently taken from a system-internal clock, and the geographic coordinates are extracted from database resources and mapped by map matching. It is then easily possible to determine the speeds of all participants or terminals that move through one cell area to the next. If, for example, a particular motorway section is monitored, it is possible to take into account only those terminals which have exceeded a cell area limit in predefined cells (namely those which correspond to the desired motorway section) in order to reduce the computational effort, ie, the amount of data to be processed is additionally reduced from the outset. Then all those terminals can be filtered out, whose speed does not reach a certain minimum value or does not fall within a certain interval, of course, here is to take the prevailing traffic conditions consideration. Furthermore, all participants of public transport (ie eg terminals that are carried on buses) are excluded, for which a comparison with historical data or with schedules of public transport can be used as the basis; On the other hand, the public traffic can also be excluded directly from the recorded data, for example by comparing periodic peaks, which arise due to public transport, or in particular if there are identical time stamps for each of several terminals, since the terminals (if they exceed a certain minimum ) not in conventional vehicles, but in buses, especially in public transport, be carried.

When removing the mentioned update data in the area of the central mobile switching centers, as mentioned, the data of the candidate "first" cells can be directly selected and the messages from other cells, for example when a terminal is active and therefore continuously transmits messages from other cells during cell changes be immediately discarded, to keep the amount of data from the outset in this respect particularly low. By means of data filtering, the desired position (update) data can be extracted from the signaling data that is acquired, and only these localization update data are recorded or stored for further processing. Furthermore, it is also possible in data processing to subject position data which has only been provided with a time stamp (so that no average speed can be determined by a cell range) to a limited utilization (count). These position data point to vehicles with terminals that have interrupted or stopped their journey in the considered cell area.

For the derivation of the respective desired traffic flow information (for example regarding density of traffic, rate of traffic, mean driving speed of the vehicles or number of vehicles at certain times) in data processing, the data used to obtain the traffic flow information by known per se Data filters are smoothed. Typical known data filters that can be used here are lowpass filters (in the frequency domain), moving average data filters or Kalman filters.

The probes can be formed by network cards installed in the area of the central exchanges, which have a high-inductance input.

In order not to burden the respective mobile radio network or its facilities, the probes and downstream units of the present system are installed independently of the cellular network; In particular, separate, independent computer means and the like are thus provided in order to achieve the desired information acquisition.

• Fig. 1 schematisch einen Teil eines zellularen Netzwerks mit zu zwei Zellen-Bereichen gehörigen Zellen und einem Verkehrsweg, zwecks Veranschaulichung des Prinzips der Positions-bezogenen Signalisierungsdaten;
• Fig. 2 schematisch die Hierarchie eines GSM-Netzwerks;
• Fig. 3 schematisch einen Teil eines GSM-Netzwerks mit einem daran angekoppelten System zur Gewinnung von Verkehrsfluss-Informationen gemäß der Erfindung;
• Fig. 4 einen Protokollstapel einer Positions-Aktualisierungs-Anfrage;
• Fig. 5 die Signalisierungen und Nachrichten bei einem Positions-Aktualisierungs-Vorgang;
• Fig. 6 die Formate und die Hierarchie (Protokollstapel) für eine Positions-Aktualisierungs-Anfrage;
• Fig. 7 in einem Schema die Erfassung der Signalisierungsdaten im Bereich einer zentralen Funkvermittlungsstelle mit einer Netzwerkskarten-Sonde, einem Sonden-Server und einer verteilten Datenbank;
• Fig. 8 ein Blockschema zur Veranschaulichung der Datenaufbereitung für die spätere Analyse; Fig. 8A ein Ablaufdiagramm zur Veranschaulichung der Arbeitsweise bei der Datenaufbereitung;
• Fig. 9 in einem Diagramm die Anzahl von erfassten Ereignissen (d.h. von erfassten mobilen Endgeräten) über der Zeit mit einer zusätzlichen Kurve nach Glättung der erhaltenen Daten, und zwar einerseits für den tatsächlichen Verkehrsstrom und andererseits für die erfindungsgemäß erfassten Positions-Aktualisierungen; und
• Fig. 10 ebenfalls in einem Vergleich mit dem tatsächlichen Verkehr die über einen Tag aufgenommenen Positions-Aktualisierungen, wobei in einer zusätzlichen Kurve die Anzahl der "verfolgten" mobilen Endgeräte, die sich durch mehrere Zellen-Bereiche hindurch bewegen, veranschaulicht ist.

The invention will be explained below with reference to particularly preferred embodiments, to which it should not be limited, and with reference to the drawings. In detail in the drawing:

• Fig. 1 schematically a part of a cellular network with cells belonging to two cell areas and a traffic route, for the purpose of illustrating the principle of location-related signaling data;
• Fig. 2 schematically the hierarchy of a GSM network;
• Fig. 3 schematically a portion of a GSM network with a coupled system for obtaining traffic flow information according to the invention;
• Fig. 4 a protocol stack of a position update request;
• Fig. 5 the signaling and messages in a position updating process;
• Fig. 6 the formats and hierarchy (protocol stack) for a position update request;
• Fig. 7 in a diagram, the detection of the signaling data in the area of a central mobile switching center with a network card probe, a probe server and a distributed database;
• Fig. 8 a block diagram illustrating the data preparation for the later analysis; Fig. 8A a flow chart illustrating the operation in the data processing;
• Fig. 9 in a diagram, the number of detected events (ie of detected mobile terminals) over time with an additional curve after smoothing the data obtained, on the one hand for the actual traffic flow and on the other hand for the inventively detected position updates; and
• Fig. 10 also in a comparison with the actual traffic recorded over a day position updates, wherein in an additional curve, the number of "tracked" mobile terminals, which move through several cell areas, is illustrated.

In the following, the invention is explained by way of example in connection with a GSM network, but as already indicated, the invention can be used in the same way for other cellular mobile networks in which cells are grouped into logical groups, called cell areas, in which a subscriber can be "paged" if a call is received for him. These logical groups of cells are called "Location Areas" (LA) in the case of a GSM (Global System for Mobile Communications) network, in the case of a Packet Switched GPRS (General Packet Radio Service) network. "Routing Areas" (RA), in the case of a UMTS network, a network independent of the GSM network (UMTS - "Universal Mobile Telecommunication System") "Location Areas", "Routing Areas" or "UTRAN Registration Areas" ( URA).

If the telephone number of a mobile station MS, referred to here as a mobile terminal, is selected, the call is routed through the telephone network to the responsible gateway radio exchange from which a connection to the HLR (Home Location Register) to verify the validity of the called number and the authorization to use the requested services. The HLR then requests from the VLR (Visitor Location Register) the roaming number of the subscriber, and based on this roaming number, the HLR can then determine the central mobile switching center, which is currently responsible for the mobile terminal. If the mobile terminal is currently available, which is verified by the central office via the VLR, the mobile services switching center will start broadcasting through all connected cells, called "paging". This broadcast message is sent by the BTS (base transceiver station) base stations of the BSS (base station subsystem).

In order to enable this "paging", all mobile devices, whether they are only switched on or actively used, when entering a new cell area using the normal so-called Location Updates (LU - general localization updates) detected, so that the cell area is known in which the affected mobile terminal is currently located. This location update (in general: this position update) is accordingly a mandatory procedure for all mobile devices, and the corresponding messages are generated by the mobile terminal or / and by the central mobile switching center and transmitted transparently between the mobile terminal and the central mobile switching center. (The central mobile switching center is also called MSC - Mobile Switching Center.)

Comparable updates to the localization of mobile devices are in the case of GPRS (where these updates are called RAU - Routing Area Updates) and the UMTS network.

Fig. 1 now schematically shows two cell areas (Location Areas - LA) LA A and LA B, each having a number of cells Z, for example, each first cell Z A1 and Z B1 along a traffic route V, about a highway, seen in the direction of travel ( arrow) of a mobile terminal MS (MS - Mobile Station) moving in a vehicle along the traffic route V.

In each cell Z, the mobile terminal MS is connected via a base station BTS (see also FIG Fig. 2 ) are integrated into the call connection, and all base stations BTS of a cell area are controlled and controlled by at least one base station controller BSC, cf. Fig. 2 , Accordingly, a base station controller BSC defines or multiple base station controllers BSC together define a cell area LA, respectively. (However, for the sake of simplicity, in the examples described below, it is assumed that a base station controller BSC defines a cell area LA.)

According to Fig. 2 For example, the base station controllers BSC are assigned to a common central mobile switching center MSC. In a mobile network then usually several such mobile switching centers MSC are provided and interconnected, s. also Fig. 3 ,

In Fig. 1 Furthermore, for the sake of completeness, a so-called handover procedure is also schematically indicated, which takes place during a cell change during an ongoing conversation, ie when the speaking participant moves across cell boundaries. This "handover" is indicated in the region of the cell boundaries 1 and 2 with thick lines, wherein in the case of the cell boundary 2 at the same time also the boundary between the cell areas LA A and LA B is given.

Apart from this special handover process, in which the speaking subscriber is passed on, so to speak, from one base station to the next, there are further procedures in a GSM network which deal with the mobility of subscribers in the network. As already mentioned, the prerequisite must always be that a subscriber can be paged, so that this subscriber, who is somewhere in the network area, can also be called, or that a message, for example a short message (SMS), can be sent to him. For this purpose, as mentioned with the help of localization updates from the network, the respective cell area, eg LA A or LA B, detected, in which the participant enters, so that the current location of the subscriber, ie a powered-up mobile terminal (not active must be) is constantly updated with a certain granularity.

The interfaces BTS and the respective associated base stations controller that is the so-called A _bis interface between the base stations are monitored - for this position monitoring could in itself - and this was so far the prior art. Out Fig. 2 It is already clear here that then in a network actually a very large number of such A _bis interfaces or connections are to be monitored, whereby the really interesting position data must be extracted from a plethora of data, so that not only a high expenditure on equipment, but a considerable procedural effort is associated with it. In addition, in this area, the hardware components are often designed differently depending on the manufacturer, so that appropriate adaptations are necessary for the data extraction.

The interfaces or connections between the individual base station controllers BSC and the respective associated central mobile switching centers MSC are called A-interfaces or A-connections, where as Fig. 2 Immediately apparent compared to the A _bis interfaces much less A-interfaces or A-compounds must be present or monitored. As a result, if data is extracted at this point, the effort can be substantially reduced, apart from the advantage that usually standardized hardware components are present at this point, so that no adjustments of the probes for the data acquisition are required. Furthermore, the data can in each case be concentratedly recorded in the area of a central mobile switching center MSC, so that there is also a simplification for the data transmission, for its further processing for the purpose of obtaining traffic flow information. This is out of the box Fig. 2 also directly out Fig. 3 It can be seen where various directly connected probes 4 in the A connections to the associated base station controllers BSC are illustrated in the area of central mobile switching centers MSC, for example the central station 3.

For the sake of completeness is in the scheme of Fig. 3 also in the lower right area in detail a base station controller BSC with base stations connected via an A _to interface BTS and with a probe 4 assigned to the A-connection (BTS - Base Transceiver Station).

The probes 4 transmit the recorded data, namely the usual SS7 messages (SS7, also SS # 7 - Signaling System No. 7 - Signaling System No. 7, an international telecommunication standard of the ITU) to a monitoring unit 5.

The SS7 messages correspond to a protocol stack with 7 layers, the layers essential here (above the MTP1 to MTP3 layers (MTP - message transfer part) the SCCP layer (SCCP - Signaling Connection Control Part)). Control part) and the layers are over it.

The monitoring unit 5, together with a data filter unit 6, belongs to a data preparation unit 7, from which the extracted localization update data are stored in a database 8 (which may also be a distributed database). In this database 8 accessed by one or more computer means analysis unit 9 accesses, said analysis unit 9 is further connected to another database 10, are stored in the geographical data or coordinates. With the help of the analysis unit 9 obtained traffic flow information are finally output via an output unit 11, for example, printed or displayed on a display. Of course, the analysis unit 9 as well as the monitoring unit 5 is associated with an input unit (but what in Fig. 3 not shown in detail), so as to, for example, the respective traffic route V (s. Fig. 1 ) and thus to determine those probes 4, which determine the monitoring of this traffic route V with respect to moving on, ie in vehicles carried mobile terminals MS. Of importance is that, although basically all base station controllers BSC are continuously monitored (can), but that in the event that only very specific traffic routes V are to be examined, only the corresponding probes 4 in the A connections from the respective mobile switching center MSC activated or switched through to the affected BSCs. This can for example be accomplished via the monitoring unit 5 by only those inputs to which the probes 4 affected by the given cell regions are connected are activated or selected there. This selection can be carried out via a separate input unit on the monitoring unit 5 or, if appropriate, also via the analysis unit 9 (or the computer means implementing this analysis unit 9), in which case a corresponding connection between this analysis unit 9 and the monitoring unit 5 will be provided. This is schematically in Fig. 3 indicated by a dashed connection 12.

• Protokolldiskriminator
• Chiffrierschlüssel-Laufnummer
• Art des Location-Updates (normal, periodisch, Anhang zu einer Teilnehmer-Identifikation)
• Identifizierung (Kennung) des Zellen-Bereichs (Location Area Code - LAC)
• Klassenbezeichnung des mobilen Endgerätes
• Kennung des mobilen Endgerätes (TMSI oder IMSI)

In Fig. 4 schematically illustrates a protocol stack of a location update request (Location Updating Request). This is the format that exists at the A interface. The information elements of such a localization update request are as follows:

• protocol discriminator
• Encryption key sequence number
• Type of location update (normal, periodic, attachment to a participant identification)
• Identification (Identification) of the Cell Area (Location Area Code - LAC)
• Class designation of the mobile terminal
• Identification of the mobile terminal (TMSI or IMSI)

Of these information elements, the following three elements are of interest: primary the identification of the cell area; then the identifier of the subscriber, i. the mobile terminal so as to be able to follow this subscriber; and, moreover, the location update type prefers to filter out the normal location updates from all MM messages (MM mobility management).

The DTAP message (DTAP - Direct Transfer Application Part - Remote application part) is encapsulated by the base station controller BSC encapsulated in a BSSMAP (BSS Management Application Part) message. This information includes the identification of the currently serving cell (cell ID) and the identification of the corresponding cell area (LAC). The associated information element is called CL3I (Complete Layer 3 Information, complete layer) and it is part of the BSSMAP message. If necessary, the BSSMAP message is sent as an optional parameter in a connection request (CR) when an SS7 connection is established between the base station controller BSC and the (associated) central mobile switching center MSC. For its part, the central mobile switching center MSC will accept the location update request (Location Updating Accept) or reject it (Location Updating Reject), cf. also the signaling operations according to Fig. 5 ,

• SCCP - Signalling Connection Control Part - Signalisierungsverbindungs-Steuerteil
• CR - Connection Request - Verbindungsanfrage
• LAC old - alter Location Area Code
• LAC new - neuer Location Area Code
• Cell ID new - Identifikation der neuen Zelle
• CC - Connection Confirm - Verbindungsbestätigung
• DT1 - Dataform 1 - Datenform 1
• RLSD - Released - freigegeben
• RLC - Release complete - Freigabe komplett

In 4 and 5 Overall, the following standardized signaling messages and operations are shown in a localization update:

• SCCP - Signaling Connection Control Part - signaling connection control part
• CR - Connection Request - connection request
• LAC old - old Location Area Code
• LAC new - new Location Area Code
• Cell ID new - Identification of the new cell
• CC - Connection Confirm - Connection confirmation
• DT1 - Dataform 1 - Data Form 1
• RLSD - Released - Released
• RLC - Release complete - Release complete

From the above brief overview of signaling and protocol stacks in location updating requests, it can be seen that the information or data of interest here for each mobile terminal MS, which changes from a cell area LA A to a subsequent LA B, at the A interfaces are available and therefore extracted therefrom and filtered or separated from other data that is discarded and sent for processing. It is typical that, although within a respective cell area LA limited information about the individual cells are available, but that this cell information sufficient for the position data determination, since in each case the first cell, eg Z B1, a cell range , eg LA B, when the vehicle with the mobile terminal MS changes from the one, first, cell area LA A into the following, second cell area LA B. About the above-mentioned normal localization update process when changing from one cell area, eg LA A, in the subsequent cell area, eg LA B, the identification of the new cell area, eg LA B, and the new first Cell Z B1 of this new cell area LA B known. The position of the mobile terminal MS is known with the resolution of a cell, namely the first cell, for example Z B1, and not merely in general with the resolution of the associated cell area LA B, so that a good position determination is possible. This is also advantageous if there are several traffic routes at the same time, which are to be monitored separately, or of which only one is to be monitored, since then the respective first cell can be identified, cf. for example, the cell Z A2 for the traffic route V 'in Fig. 1 ,

The sake of completeness are still based on the Fig. 6 the formats of the signaling layers above the MTP layers are explained in the case of a DTAP location updating request. The SCCP part provides connectionless and connection-oriented network services above MTP layer 3. While MTP3 provides connection point codes for directing messages to specific signaling sites, the SCCP part provides subsystem numbers for messages to address specific applications or subsystems at these signaling points. Specifically, the SCCP part includes a Routing Label 13, followed by a Message Type Specifying Code 14 that is binding on all messages. This message type code uniquely defines the function and format of each SCCP message. This is followed by a binding fixed part 15, ie a fixed-length binding part for each message type, whereas the subsequent part 16, which is also binding in its own right, is a part of variable length, the name of each parameter in this part and the order, in the pointer (pointer) is sent implicitly in the message type. Finally, there follows an optional part 17, which contains parameters that may or may not occur in the respective message type. Fixed length parameters as well as variable length parameters may be included. Each optional parameter contains the parameter name, a length specification and the parameter content.

In this part 17, the BSSAP part is transmitted, which again contains the actual data preceding header data 18 concerning the message type and a data part 19 concerning the length of the message. In the payload, the BSSMAP part is transmitted, in which a byte, part 20, the cell identifier 21, followed by the layer 3 information 22 follows, following a message type. The cell identifier 21 includes in a part 23 the element ID, in a part 24 a length indication and in a part 25 a discriminator; then follow the cell identification information, namely first the part 26 with the Location Area Code (LAC) and then the actual cell identification 27. In the layer 3 information are again first 28, 29 concerning element identification (element ID) and length, and then, in part 30, the contents of the layer 3 information. The base station controller submits the incoming location updating request in the layer 3 information and sends this message to the associated central mobile switching center MSC.

Within the layer 3 information 30 is a protocol discriminator 31 (eg Mobility Management - MM) then an indication 32 concerning message type, a cipher key sequence number 33, an indication 34 concerning the type of location updating (eg normal or periodic), then the location area (cell area) identification 35, with the Mobile Country Code (MCC) code and the actual LAC code, the terminal class name 36 already mentioned, and finally the identifier of the mobile terminal, part 37, this identifier 37 of the terminal being either the usual IMSI or TMSI Identification may include.

As can thus be seen, at this point, thus at the A interface, all the necessary information is present to allow a mobile terminal MS to change from a cell area, e.g. LA A, to the next, e.g. LA B, and to track over several such cell-area changes. Thus, the simple possibility described is given, in the case of carrying mobile terminals MS in vehicles that move on a monitored traffic route V, these mobile terminals MS with the accuracy of a cell (namely always the first cell, eg Z A1 and Z B1, a newly entered cell area) and thus track from cell area to cell area.

In Fig. 7 the data acquisition is shown in more detail in a central mobile switching center MSC with the aid of a probe 4 in the form of a network card, whereby the network card inductively senses the standard E1 connections present there and thus the data to the data preparation unit 7 transferred to these E1 connections Called probe server transmits. With the bus system 38 it is indicated that corresponding data transfers to the unit 7 take place from a plurality of such probes 4. The term "E1" is a CEPT standard with a transmission rate of 2,048 Mbit / s, with 30 64 kbit channels (digital channels) for voice and data transmissions as well as a 64 kbit / s signaling channel and another 64 kbit / s Channel are available for framing and maintenance. The usable here probes 4 in the form of network cards E1 / T1 are standard network cards, as provided by various manufacturers, such as the part of the Network operator to perform internal monitoring, and these network cards can be used for the data acquisition invention in the same way.

In detail, the network card probes 4 can be installed directly in the probe server 7, which is thus arranged in the region of the E1 connections. The probe server 7 is a computer which subjects the captured data to first processing. The data processing unit 7 may further be associated with a database system 8 having a plurality of database servers 39 in which the recorded data is kept available for computer access.

In particular, it may be in the configuration according to Fig. 7 in the distributed database around the database 8 according to Fig. 3 act, and the probe server 7 includes the monitoring unit 5 and the data filter unit 6 according to Fig. 3 , The data filter unit 6 is also called a "parser". The operation of this combined data processing unit 7 is described below with reference to the scheme according to Fig. 8 and the flowchart according to Fig. 8A explained in more detail.

In Fig. 8 is more clearly illustrated for the "parser" 6 that in a module 40 a message is taken over from an affected connection, after which in a module 41 messages from irrelevant cells are discarded. According to a module 42, the location updating requests are then detected by filtering, and in a module 43 the complete layer 3 information including the cell identification (cell ID) and the location area identification (LAC) is read. The location updating request including the MS identifier (the TMSI / IMSI) and the location area code LAC is then read in the module 44, and then the data thus obtained is provided with a time stamp in the module 45. The time stamp data is taken from a system-internal clock. Following this, the data or messages with associated time stamp are finally stored in the database unit 8 or 39, s. Block 46.

According to the accompanying, in Fig. 8A shown flow chart is upon receipt of the respective message, s. Field 50, in a query field 51 checks whether the message of a cell to be monitored (eg Z B1 according to Fig. 1 ) or not, and if not, continues to field 52 to wait for the next message. If, on the other hand, a cell of interest is involved, then in block 53 the received message is read and in block 54 the protocols are analyzed as described. Thereafter, an inquiry field 55 queries whether a Location Updating (LU) request (LU Req) is present; if so, the LU query is queued in block 56. If there is no LU request, ie the result of the query in field 55 is negative, a check is made in a next query field 57 as to whether a Location Updating Acceptance Message (LU Accept) is present, and if so, it is checked according to field 58, whether a corresponding request is already in the queue, s. Block 56. If appropriate, then a corresponding entry of the listed data is made in the database 8, s. Block 59 in Fig. 8A , However, if it is determined in the query according to field 57 that there is no LU assumption, then in accordance with query field 60 it is queried whether there is an LU reject (LU reject); if not, in this process, the system returns to block 52 and waits for the next message; if, on the other hand, the query result in field 60 is positive, it is again checked in accordance with an inquiry field 61 whether the LU request is in the queue, and if so, the LU request is deleted from the queue according to block 62. Incidentally, the system returns to block 52 and waits for the next message.

On the basis of the position data thus obtained and stored with MS identification, it is now possible, in particular using conventional statistical methods, to obtain information concerning the traffic flow on the particular traffic route V considered. Estimates of the traffic density on the traffic route V can be obtained from the filtered signaling data by smoothing with a conventional data filter algorithm on the one hand, and the speed of the individual subscribers, ie of the individual vehicles in which mobile terminals MS are carried, can be estimated. where respectively the average speed of a vehicle or more precisely a mobile terminal is determined by a cell area, eg LA A, as well as by further cell areas along the traffic route V. From these vehicle speeds, as well as from the estimation of the traffic density, further insights regarding the traffic situation on the observed traffic route can be obtained, such as assumptions regarding congestion, crawling traffic, unrestricted traffic and the like traffic situations.

With regard to the density of the traffic on the respective monitored traffic route V, the mobile terminals MS in each case simply move in a vehicle moving along the route V, in each case entering a new cell area and identifying the first cell of this cell. Range, and these events are summed over time; It is expedient for trend detections etc., also made a smoothing of the filtered data according to a conventional method, as in Fig. 9 is illustrated. In this Fig. 9 the upper curve 70 shows the averaged curve corresponding to the smoothed data of the actual traffic detected by means of sensors installed on the traffic route V on the traffic route V over time (in hours); the actual traffic flow is indicated by dotted lines 71, where it can be seen that there are very large instantaneous fluctuations, so that an averaging or smoothing is recommended. Furthermore, the averaged curve 72 in FIG Fig. 9 that traffic which was detected on the basis of the aforementioned location updates due to mobile terminals MS carried along in vehicles, whereas the actual, "high-frequency" traffic flow detected on the basis of the location updates is illustrated by means of dotted lines 73. Out Fig. 9 can be seen that after the averaging the data curve 72, which was obtained due to the location updates, relatively well in terms of quality of the actual traffic volume curve 70 corresponds, so that based on experience based on the data curve 72 on the actual traffic can be closed. The lower values of the curve 72 in comparison with the curve 70 result from the fact that not every vehicle carries a mobile terminal switched on, and that it does not on the other hand, it is also conceivable that, if such terminals are carried, these other network operators are assigned. In the present example, it follows that approximately 1/3 of the vehicles carries an activated mobile terminal of the affected network operator with it. From this it is possible to draw conclusions about the total volume of traffic as well as the developments such as rush hours in the traffic scene with good approximation and reliability (eg by multiplying by a corresponding factor).

For data smoothing, that is, for averaging, a variety of known methods can be used, such as the Moving Average Filter method, the Exponentially Weighted Moving Average Filter method, but also a simple one Low Pass Filtering or the Kalman Filter Method. These methods are well known and need no further explanation. In any case, with the filtered, averaged data trend estimates can be derived in a reliable manner, although, as studies have shown, a smoothing with a Kalman filter for predictions in the traffic is less suitable.

As well as Fig. 9 also applies Fig. 10 to a concrete test case, whereby in detail for a day with the help of installed on a highway sensors data on the actual traffic volume were detected, see. the curve 80 in Fig. 10 , At the same time - cf. the curve 81 - detects the traffic based on the location updates regarding mobile devices, in which case further in terms of tracking the vehicles (ie when the vehicles with the mobile terminal MS several cell areas traverse one behind the other and thus traced by several cell areas in a row are) the dashed line curve 82 was obtained. Again, due to the principle of the individual curves 80, 81 and 82, that a good correlation of the curves is given, so that it is permissible, based on the data about as the curve 81 or the curve 82 on the entire traffic flow according to curve 80 conclusions.

To mention here is still that in Fig. 10 in the actual traffic data curve 80 after about 10 hours a failure of a sensor was detected, so that there was a break-in 83 in the curve 80. Additionally, in the present monitoring system, after about 13 hours of the observation period, the surveillance system went out of control for about one hour, as indicated by a break 84 in curves 81 and 82. In any case, apart from these failures 83, 84 in the data acquisition, it turns out that the curves 81 and 82 are quite representative, so that the underlying data is suitable for obtaining the desired traffic flow information.

In the data analysis in the analysis unit 9 ( Fig. 3 In a conventional manner, the individual cell identifications are assigned the (known) geographic coordinates which are taken from the database 10. This assignment can be made using conventional algorithms or map data mappings.

When evaluating the data, initially only those mobile terminals MS, ie subscribers or vehicles, can be taken into account, which in the case of predefined cells, eg Z B1 in FIG Fig. 1 that have exceeded cell range limits. This essentially involves counting the participants at the points concerned. The subscribers can then be tracked over at least two range changes, and based on the time stamps at the respective first cells, eg Z A1 and Z B1, the average time for traversing the respective cell range, eg LA A, is determined. This determination of the average speed can also be carried out over several cell area boundaries, which corresponds to a further "tracking" of the affected participants. It is now possible to discard those subscribers or terminals MS whose speed does not fall within a predetermined interval, whereby, of course, the prevailing traffic conditions (free traffic, slow traffic, congestion, etc.) must be taken into account. Furthermore, all participants in public transport can be excluded by the periodic peaks corresponding to the travel times of the vehicles in the recorded Comparing data curves obtained due to public transport; another possibility is to ignore public transport by comparing the data obtained with historical data and public transport timetables.

Furthermore, multiple location updates resulting from the so-called ping-pong effect can be filtered out.

In this way, it is altogether possible with the described technique to analyze traffic conditions, such as estimating the traffic volume, or to determine the average speed of the vehicles, as well as the number of calls from the considered traffic or the number of times participants in the traffic route area can be called, can be determined.

As mentioned, the principle described above applies in the same way as for the GSM network also for other cellular radio network systems, and the invention is thus not limited to the application to the GSM network described here by way of example.

Claims (21)

1. A method for acquiring traffic flow information, wherein position data including an identification of at least one switched-on mobile station (MS) on board of a vehicle is obtained from signalling data in the region of at least one mobile switching center (MSC) of a cellular network on the interface (A) between said mobile switching center (MSC) and associated base station controllers (BSC) defining individual location areas (LA), said position data is combined with time stamp data, and the combined position data is assigned map data along with which it is processed to obtain said traffic flow information, characterized in that the position data including the mobile station identification, upon each entry of the vehicle into a new location area (LA B), is obtained from localization update data including the DTAP (direct transfer application part) messages and the CL3I information (complete layer 3 information) and, in doing so, the identification of the first cell (Z B1) in the new location area (LA B) is used in addition to the mobile station identification and the identification of the old location area (LA A), wherein the part referring to the position/identification of the respective first cell (Z B1) of the new location area (LA B) is separated when obtaining the position data.
2. The method according to claim 1, characterized in that, for the popping of the signalling data in the region of the mobile switching center (MSC), the identification of the first cell (Z B1) is preset, and signalling data of other cells (Z) based on their different identifications is discarded.
3. The method according to claim 2, characterized in that localization update data is extracted from the signalling data by data filtering, and only this localization update data is stored.
4. The method according to any one of claim 1 to 3, characterized in that the mean velocity of the movement of the vehicle through the first one (LA A) of the two consecutive location areas (LA A, LA B) is calculated from the difference of the time stamp data of position data obtained upon entry into first cells (Z A1, Z B1) of consecutive location areas (LA A, LA B), with assignment of the map data.
5. The method according to any one of claim 1 to 4, characterized in that, during data processing, that position data which is indicative of mobile stations (MS) on board of means of mass transport, particularly public means of transport, is discarded.
6. The method according to any one of claim 1 to 5, characterized in that, during data processing, that position data which was only provided with one time stamp for a location area (LA) is subjected to data processing merely based on the count of vehicles, being indicative of vehicles interrupting their travels in the considered location area.
7. The method according to any one of claim 1 to 6, characterized in that, during data processing, the data used for obtaining traffic flow information is smoothed by data filters.
8. The method according to any one of claim 1 to 7, characterized in that, based on the combined position and map data, an estimation of the traffic density and/or a mean traffic velocity is performed at specified times on specified routes (V).
9. A system for acquiring traffic flow information, wherein, for obtaining position data including an identification of at least one active mobile station (MS) on board of a vehicle from signalling data between base transceiver stations (BTS) and at least one mobile switching center (MSC) of a cellular network including cells assembled in location areas, probes (4) are arranged at the links between the base transceiver stations and the mobile switching center, and a monitoring unit (5) is connected to the probes (4) to acquire signalling data, which is fed to an analyzing unit (9) to which database means (10) for map data is further assigned, characterized in that the probes (4), in the region of the mobile switching center (MSC), are arranged at the interfaces (A) of the latter to base station controllers (BSC) each defining a location area (LA A, LA B), in order to acquire and use the identification of the first cell (Z B1) in the new location area (LA B) when obtaining the position data from signalling data upon entry of the respective vehicle into a new location area (LA B), from localization update data including the DTAP (direct transfer application part) messages and the CL3I information (complete layer 3 information).
10. The system according to claim 9, characterized by a data preparation unit (7) provided between the probes (4) and the analyzing unit (9), which data preparation unit (7) is arranged to assign time stamp data to the individual position data.
11. The system according to claim 10, characterized in that the data preparation unit (7) comprises a data filtering unit (6).
12. The system according to claim 11, characterized in that the data filtering unit (6) is arranged to separate from the signalling data that data part referring to the position/ identification of the respective first cell (Z B1) of the new location area (LA B).
13. The system according to any one of claims 10 to 12, characterized in that the data preparation unit (7) is arranged to extract the signalling data of specified first cells and to discard those of cells (Z) other than the specified first cells (Z B1) of the location areas (LA B).
14. The system according to any one of claims 10 to 13, characterized in that the data preparation unit (7) is arranged to separate localization update data from the signalling data and to discard any other data.
15. The system according to any one of claims 9 to 14, characterized in that the analyzing unit (9) is arranged to calculate, from the difference of the time stamp data of position data obtained upon entry into first cells (Z B1) of consecutive location areas (LA B), with assignment of map data, the mean velocity of the movement of the vehicle through the first one (LA A) of the two consecutive location areas.
16. The system according to any one of claims 9 to 15, characterized in that the analyzing unit (9) is arranged to discard the position data which is indicative of mobile stations (MS) on board of means of mass transport, particularly public means of transport.
17. The system according to any one of claim 9 to 16, characterized in that the analyzing unit (9) is arranged to subject the position data which was only provided with one time stamp to data processing merely based on the count of vehicles, being indicative of vehicles interrupting their travels in the considered location area.
18. The system according to any one of claim 9 to 17, characterized in that the analyzing unit (9) is arranged to smooth the data used for obtaining the traffic flow information by data filter.
19. The system according to any one of claim 9 to 18, characterized in that the analyzing unit (9) is arranged to perform an estimation of the traffic volume at specified times on specified routes, based on the combined position and map data.
20. The system according to any one of claim 9 to 19, characterized in that the probes (4) are formed by network interface cards equipped with inductive sensors.
21. The system according to any one of claim 9 to 20, characterized in that the probes (4) and consecutively arranged units (7, 9) are installed independently of the cellular network.

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