System and method for geographically locating a cellular device

ES 2 567 136 T3

DESCRIPTION

System and method to geographically locate a cellular device

Technical field

This invention relates to systems and methods for geographically locating cellular devices; and in particular to the use of such systems and methods to locate vehicles in a traffic information system. The invention has application with all types of devices that communicate with wireless networks, for example, but not exclusively, networks based on GSM, GPRS, EDGE, CDMA and CDMA broadband.

Background

Determining the geographic location of a cellular device, such as a mobile phone, is useful in a variety of applications, including applications in the field of location-based services. In traffic information systems, for example, vehicle locations can be determined based on cellular device locations of drivers in order to form an image of traffic conditions. The location of a cellular device or similar wireless device can be determined based on data acquired from the cellular network itself. In particular, the location of a device can be specified in terms of the network cell in which the cellular device is located, which is defined by a cell identifier, possibly in addition to other data such as a time advance.

Certain alternative techniques involve sampling data at a relatively low level in the network (closer to base stations), such as the A bis interface in GSM networks, for example using signal strength power measurement reports from mobile devices. Techniques based on low-level interfaces in the network are difficult and expensive to implement. Certain alternative techniques applied in traffic monitoring rely on repetitively recording handover patterns on driving routes and storing the patterns in a database for use in subsequent route determinations based on pattern matching.

Neither of these alternative techniques offers a cost efficient and accurate technique for determining the geographic location of cellular devices. The present invention seeks to provide improved techniques for determining the geographic location of cellular devices.

US 5,432,8426 shows a topology of two base stations each with a cell boundary and with a handover area where cells overlap. WO 95/02307 shows a topology of two co-located base stations with a handover area.

Compendium

According to one aspect of the present invention there is provided a method for geographically locating a cellular device, the method comprising:

determining an effective cell area for each of a first cell sector and a second cell sector in a cellular network, wherein determining an effective cell area for each cell sector comprises determining an effective cell sector radius to determine a sector area and extending the sector area by extending an edge of the sector based on a relationship of positions and orientations Relating to a first antenna of the first cell sector and a second antenna of the second cell sector; and determining a handover area within which the cellular device is likely to be located when control of the cellular device is transferred from the first cell sector to the second cell sector, the handover area comprising at least part of an intersection between the effective cell area of ​​the first cell sector and the effective cell area of ​​the second cell sector.

According to another aspect of the present invention, there is provided a method for geographically locating a cellular device in a cellular network comprising a first antenna for a first cell and a second antenna for a second cell, the method comprising:

determining an effective radius Ri for each of a set of i different topological relationships between the first cell and the second cell;

determine an angle V for which, when the first antenna is contained within the second cell and when an angle 3 formed by a line between the first antenna and the second antenna and a sector boundary line of the second cell is less than an angle V, the second cell will extend beyond the sector boundary line;

determining a first extension width E1 of a first rectangular extension added to a sector boundary line of the second cell when angle 3 is less than angle V;

determine a second extension width E2 of a second rectangular extension added to a sector boundary line of the second cell when the first antenna is outside the second cell and when an angle

Inner ES 2 567 136 T3 formed between a sector boundary line of the second cell and a line between the first antenna and the second antenna, is greater than 180 degrees;

determining a first penumbra width W1 of a first rectangular band between a line of equal signal reception intensity from the first antenna and the second antenna and a boundary of the first band proximal to a cell to which the cellular device is moving;

determining a second penumbra width W2 of a second rectangular band between the line of equal intensity and a boundary of the second band proximal to a cell out of which the cellular device is moving; and determining a handover area within which the cell phone is likely to be located when control of the cellular device is transferred from the first cell to the second cell, determining the handover area that is based on at least a subset of the effective radii Ri, the angle V, the first extension width E1, the second extension width E2, the first penumbra width W1 and the second penumbra width W2.

According to another aspect of the present invention, there is provided an apparatus for geographically locating a cellular device, the apparatus comprising:

an effective cell area modulus for determining an effective cell area for each of a first cell sector and a second cell sector in a cellular network, wherein determining an effective cell area for each cell sector comprises determining an effective cell sector radius to determine a sector area and extending the sector area by extending an edge of the sector based on a relationship of positions and orientations Relating to a first antenna of the first cell sector and a second antenna of the second cell sector; and a handover area module for determining a handover area within which the cellular device is likely to be located when control of the cellular device is transferred from the first cell sector to the second cell sector, the handover area that it comprises at least part of an intersection between the effective cell area of ​​the first cell sector and the effective cell area of ​​the second cell sector.

Additional advantages and novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following and the accompanying drawings; or it can be learned by practice of the invention.

Brief description of the drawings

For a better understanding of the present invention and to show how it can be carried out, reference will now be made, by way of example only, to the accompanying drawings, in which:

Fig. 1 shows a first and a second cell of a cellular network having antennas located at the same point, according to an embodiment of the invention;

Fig. 2 shows a first and a second cell of a cellular network, the cells having antennas located at different points and oriented opposite each other, according to an embodiment of the invention;

Fig. 3 shows first and second cells of a cellular network, cells having antennas located at different points and having sectors that do not overlap, according to an embodiment of the invention;

Fig. 4 shows a first and a second cell of a cellular network, the cells having antennas located at different points, which face each other at an acute angle and whose sectors overlap, according to an embodiment of the invention;

Fig. 5 shows an effective cell area with extensions of one sector when an antenna is contained in the sector of another cell, close to one of its boundary lines, according to an embodiment of the invention;

Fig. 6A shows an effective cell area with extensions of one sector when a second antenna is outside the sector boundaries of a first antenna and when an interior angle criterion is satisfied for two edges of the sector, according to an embodiment of the invention;

Fig. 6B shows an effective cell area with extensions of one sector when a second antenna is outside the sector boundaries of a first antenna and when an interior angle criterion is satisfied for an edge of the sector, according to one embodiment of the invention;

Fig. 7 illustrates the determination of a penumbra area around the line of equal intensity between two antennas, in the case where two cells have antennas located at the same point, according to an embodiment of the invention;

Fig. 8 illustrates the determination of a penumbra area around the line of equal intensity between two antennas, in the case in which two cells have antennas located at different points and oriented opposite each other, according to an embodiment of the invention ;

ES 2 567 136 T3 Fig. 9 illustrates the determination of a handover area for the case where two cells have antennas located at different points and are oriented opposite each other, according to an embodiment of the invention;

Fig. 10 illustrates the determination of a crossover area for the case where a line of equal intensity is not well defined, according to an embodiment of the invention;

Fig. 11 shows a corona sector, which is used to model the estimated location of a cellular device when a cellular network uses timing advance data, in accordance with one embodiment of the invention;

Fig. 12 is a block diagram of a traffic information system, as part of which an embodiment according to the invention can be used; and Fig. 13 is a block diagram of an apparatus for locating cellular devices, according to an embodiment of the invention.

Detailed description

Cellular networks operate using a network of antennas, each of which communicates messages to and from cellular devices located in a given area, called a cell. The cell areas of different antennas overlap, so that the operating domain of the cellular network is completely covered. At any given time, a cellular device is under the control of a single cell on the network. The control cell is normally the one whose reception intensity is the strongest at the location of the cellular device. When a cellular device is in motion, it traverses from cell to cell, and its control is “rolled over” from cell to cell.

The operation and management of the cellular network requires monitoring many events that occur with respect to cellular devices. Such events are related for example to the calls you are making, such as call initiation and call termination and your mobility, such as location updates and handovers. We use some GSM technology terminology in the following description, but wherever it is used we try to refer to parallel terms in other network technologies as well.

The use of some or all of these events, especially those events that are logged on "Interface A" (or the "parallel" in certain network technologies) provides a cost-effective method of locating a cellular device. Below we describe a way to extract the location from among the handover events, but this can be done for other events that are logged and can be connected to a concurrent control of more than one cell.

While the preferred embodiments described herein are described with respect to a type of hard handoffs that apply for example in GSM-based networks, the principles and benefits of the invention also apply to soft handoffs and combinations of hard and soft handoffs. In this context, the most basic form of handover is the one used in most 1G and 2G systems and can be thought of as where a device with a call in progress is redirected from a cell transmitter and receiver and a pair of frequencies. to another cell transmitter or receiver using a different frequency pair without interrupting the call. If the terminal can only connect to one base station and therefore needs to break the connection when connecting to the other, this is considered a strong handover.

One of skill will appreciate that in CDMA, including WCDMA-based systems, the user can connect to several base stations simultaneously, combining data from all transmitters within range into one signal using a RAKE receiver. The set of base stations to which the terminal is connected at one time is known as the "active set". A "soft handoff" occurs when there are several base stations in the active set and the terminal interrupts one of these to add a new one or adds a new one without interrupting an existing base station in the active set. In W-CDMA there is a special case called "soft handover" where several connections in the active set point to the same base station. A smoother handover occurs when one of these connections is interrupted by another from the same base station. There are also handovers between systems where a connection is transferred from one access technology to another, for example a call that is transferred from GSM to W-CDMA. The principles and advantages of the present invention apply with respect to all the aforementioned types of handover and the terms of the claim should be construed accordingly, although the precise implementation and / or actual benefit in each case may vary less than which will be appreciated by the experts.

Consequently, at any given time, a cellular device is under the control of one (in GSM networks) or more cells in the network. The control cell or cells are those whose reception is considered adequate for the purpose and the event of giving control to (or adding) a new cell is known herein as "handover". The handover event therefore points to a momentary situation (the exact moment of which is included in the event record) where the cell phone is under control of two or more cells, which is at a reception intensity approximately equal to the aforementioned cells. This means that by drawing the area where all said cells have approximately equal reception, it can be estimated with high probability that the cell phone is located within this area.

ES 2 567 136 T3

For clarity, the following exemplary embodiment refers to a case of transfer of control between two cells, which are relevant to GSM networks, but the same method may be involved for cases where more than two cells are involved, for example, it can be applied to an active set of cells in a CDMA-based network, applying the principles and method steps described below to all those cells.

Often a handover event in GSM and similar networks involving cell A and cell B occurs when a cellular device moves from an area where the signal strength from the antenna of cell A is greater than that of the cell. cell B antenna, to an area where the signal strength from the cell B antenna is greater than that of the cell A antenna. In this way, the handover event theoretically occurs when the cellular device crosses a signal line of equal intensity from both cells. However, in reality, the crossover does not occur exactly on the line of equal intensity, but rather within a certain area of ​​twilight around the line of equal intensity. The shape and dimension of the penumbra area depends on several parameters, including the relative placement of the cells involved, which is determined by the location and orientation of the antennas.

In the example according to the invention, a technique is described to geographically locate a cellular device with high confidence at the moment the handover occurs, determining the "handover area", which is the area in which handover could occur with high probability. from cell A to cell B. Because the handover areas are found to be smaller than the cell areas, on average, this technique offers better precision than techniques that use only the cell area to locate a device. Additionally, handover events are logged by the cellular network management system and are therefore available at no additional cost, so that the technique is relatively inexpensive.

A polygon can be constructed to represent the handover area. In order to do so, four simplifying assumptions are made.

First, the simplifying assumption is made that the control area of ​​an antenna (a cell area) is a sector, generally 120 degrees, the center of which is the antenna; see, for example, sector 101, centered around antenna 100 of the embodiment of Fig. 1.

Second, the simplifying assumption made is that the intensity of reception of signals from the antenna grows inversely with the distance from the antenna, while the cellular device is positioned within the sector. Other factors influencing the intensity of reception of signals from the antenna are ignored, such as the exact azimuth of the antenna, the effect of reflections and the effect of multipath; because the influence of such factors is limited and the factors often statistically offset each other.

The third simplifying assumption made is that the antenna reception intensity outside the sector is significantly less than the reception intensity within the sector.

The fourth simplifying assumption made is that handover from one cell to another occurs within a reasonable distance from a point where the cellular device receives a signal from both antennas at equal intensity.

Based on these assumptions, an example according to the invention initially models a cell reception area as a sector with a finite radius. Beyond that radius, reception occurs, but is significantly weaker than reception within the radius. Also, there are regions of weak reception beyond the boundary lines of a sector; and in the area behind the antenna, in the opposite direction of the sector. In some cases, control over a cellular device can be bypassed within these weak reception areas. An embodiment according to the invention therefore extends the cell reception area, initially modeled as a sector, to these weak reception areas, under certain circumstances. Once the effect of such circumstances has been considered and the cell sector area is (or not) possibly extended, the pattern resulting from cell reception is here called the effective cell area. As will further be seen later, it can be determined whether to extend a cell sector area based on the relative positions and orientations of the two antennas between which a device moves. For example, extensions can be made when a cell antenna is positioned within the other cell sector, but very close to the boundary of the sector (as in the embodiment of Fig. 5); or when a cell antenna is positioned outside the other cell sector in specific configurations (as in the embodiment of Fig. 6). In these cases, the effective cell area includes extents beyond the sector boundaries. Also, the sector radius can be extended or decreased, in some cases, based on the distance between the antennas of the two cells; the resulting radius here is called the effective radius of the cell.

Taking such effects into consideration, an embodiment according to the invention constructs a polygon representing the handover area out of a combination of two areas: 1) the overlapping part of the effective cell areas of the two cells between which the device is moving mobile; and 2) the penumbra area around the line of equal intensity between the antennas of the two cells. As will be seen later, the relative placement of the two cells plays a significant role in determining these two areas; and there are cases where the penumbra area is impossible to define and therefore only the effective cell area is used.

ES 2 567 136 T3

Figs. 1 through 4 illustrate four possible topology relative positions of two cells, according to one embodiment of the invention. In Fig. 1, a first cell 101 and a second cell 102 have antennas located at the same point 100. In Fig. 2, a first cell 201 produced by a first antenna 203 is oriented to face a second cell 202, produced by a second antenna 204; the two cells have antennas located at different points and face each other. In Fig. 3, a first cell 301 and a second cell 302 have antennas 303 and 304 located at different points and their sectors do not overlap. Fig. 4 shows an example that does not fit into the topological categories of Figs. 1 to 3, thereby representing all other topological cases; in this case, antennas 403 and 404 are located at different locations, face at an acute angle to each other, and sectors 401 and 402 overlap.

In an embodiment according to the invention, a method for geographically locating a cellular device includes three steps: first, determining the effective cell area of ​​each cell; second, determine the area of ​​penumbra around the line of equal intensity; and third, combining the areas determined in the first and second steps to determine the handover area.

A first step of an embodiment according to the invention comprises determining the effective cell area of ​​each cell. In order to do so, an effective radius of the cell sector is first determined. The existence of such a radio is based on the second simplification assumption above, that is, that the intensity of reception of the antenna within the sector grows inversely with the distance from the antenna. Determining the effective radius depends on the topological case involved: in the topology of the embodiment of Fig. 1, where the antennas are located at the same location 100, the effective radius is R1, 103. In all other topological cases, shown in the embodiments of Figs. 2 to 4, the effective radius is equal to R * D, where D is the distance between the antennas and Ri is a constant factor, different for each topological case (that is, for Figs. 2 to 4, the index i = 2, 3 and 4). According to one embodiment of the invention, other methods can be used to determine an effective radius; including other methods that relate to an increased distance between the antennas at an increased effective radius.

Next, after determining the effective radius of the cell sector, the effective cell area is determined by extending the cell sector beyond the edges of the sector, in certain cases. This determines the side lines of the effective cell area. The extension of the cell area beyond the edges of the sector is required for example in two cases: 1) when an antenna is contained in the sector of the other cell, very close to one of its boundary lines, as will be illustrated with reference to the embodiment of Fig. 5; and 2) when one antenna is outside the sector of the other cell and the interior angle between the limiting line and the line connecting both antennas is greater than 180 degrees, as will be illustrated with reference to the embodiment of Fig. 6A and 6B .

In the first case of extension, shown in the embodiment of Fig. 5, the angle β, 503 that is formed by the line 505 between the two antennas 501 and 502 and one of the limiting lines 506 of the first sector, is less than a predetermined angle a, 504. The predetermined angle a is predetermined as the angle within which an antenna 502 is close enough to the boundary line 506 to ensure an extension of the cell area beyond the edges of the sector. When the angle β is less than a, the sector extends only to one side, that is, the side 506 that is close to the second antenna 502. A relatively small rectangular extension 508, having a width dimension E1 507, is adds to the 506 side of the sector.

In the second case of extension, first described with reference to the embodiment of Fig. 6A, a second antenna 602 is outside the limits of sector 603 of a first antenna 601. In such a case, it is determined whether the interior angle is that is, the angle that the first sector 603 itself contains and that is formed between an edge 607 or 608 of the sector 603 and the line 609 between the two antennas 601 and 602, is greater than 180 degrees. If so, an extension is made to the edge of sector 607 or 608 for which that condition is satisfied. For example, consider edge 607 of sector 603. The interior angle between edge 607 and line 609 is angle 605; and that angle 605 is greater than 180 degrees. Accordingly, the edge 607 extends to a rectangular extension 610. Similarly, considering edge 608 of sector 603, the interior angle between edge 608 and line 609 is angle 606; and that angle 606 is greater than 180 degrees. Accordingly, the edge 608 extends in a rectangular extension 611. In the second extension case of FIGS. 6A and 6B, the rectangular extensions, such as extensions 610 and 611, have a relatively greater width E2, 613 than the width E1, 507 of the rectangular extent of Fig.

5. Also, when there are two rectangular extensions to a given sector, as with extensions 610 and 611 in sector 603, an additional triangular extension 612 is made on the back of antenna 601 connecting the two far corners 623 and 624 of the rectangular extensions; and the two extensions are of the same width E2. It should be noted that, while large extensions are made for sector 603 because antenna 602 is outside the bounds of antenna sector 601 (and the interior angle criterion is satisfied), the inverse is not necessarily the case. for the other sector. That is, in this case, sector 604 will not extend to an extension of the second type, because antenna 601 is within sector 604.

The embodiment of Fig. 6B shows another example of an extension of the second type, in which only one edge of a sector extends with a large extension, instead of two. In particular, antenna 615 is outside sector 616 of antenna 614. However, the interior angle 622 between edge of sector 617 and line 620 is exactly equal to 180 degrees (and therefore is not greater than 180 degrees ), so that no

ES 2 567 136 T3 extension to edge 617. In contrast, the interior angle 621 between sector edge 618 and line 620 is greater than 180 degrees; therefore, an extension 619 of the second type is made for edge 618.

Having determined the effective cell area (in this embodiment by determining an effective radius and, in some cases, extending the edges of the sector), the second step is to determine the twilight area around the line of equal intensity between the two antennas, as is illustrated with reference to the embodiments of Figs. 7 and 8. In this example, the twilight area around the line of equal intensity is modeled as an asymmetric rectangular band around the line of equal intensity. The width W1 of the rectangular band between the line of equal intensity and the band boundary on the side of the cell in which the cellular device is moving, is longer than the width W2 on the side of the cell outside of which the cellular device is moving. For example, referring to the embodiment of Fig. 7, the penumbra area around the line of equal intensity 710 is formed by two rectangular bands 706 and 707, for which the width W1, 708 of the band 706 in the side of sector 704 in which the cellular device is moving is longer than the width W2,709 of band 707 on the side of sector 705 out of which the cellular device is moving. Each band is formed between the line of equal intensity 710 and a band boundary 711 and 712. Similarly, referring to the embodiment of Fig. 8, the twilight area around the line of equal intensity 808 is formed by two rectangular bands 806 and 807, for which the width W1, 809 of band 806 on the side of sector 805 where the cellular device is moving , is longer than width W2,810 on the side of sector 804 out of which the cellular device is moving.

In determining the area of ​​penumbra around the line of equal intensity, according to an embodiment of the invention, it is first necessary to determine the location of the line of equal intensity, which varies depending on the topological case. In the first topological case of the embodiment of Fig. 1, which is also the case in Fig. 7, the line of equal intensity is the bisector 710 of the azimuths of cells 702 and 703 (emanating from location 701 of antennas). In the second and third topological cases of the embodiments of Figs. 2 and 3, the line of equal intensity is approximately the central perpendicular to the line connecting the two antennas. For example, in Fig. 8, which corresponds to the topological case of Fig. 2, the line of equal intensity is the central perpendicular 808 to the line 803 that connects the two antennas 801 and 802. In the fourth topological case of the embodiment of Fig. 4, the points of equal intensity are difficult to define and there is no band similar to those in Figs. 7 and 8.

Having determined the effective cell area and the twilight area around the line of equal intensity, a third step in this embodiment is to determine the pass-through area. For each of the topological cases except that of the embodiment of Fig. 4, the area is formed in which each cell is potentially capable of performing a handoff, for each cell, by the intersection of its effective cell area and the twilight area around the line of equal intensity. The handover area from cell A to cell B, as it is in this case, is then found as the union of the areas where the two cells are potentially capable of handover. For example, referring to the embodiment of Fig. 9, the handover area for a cellular device traveling from cell A, 901 to cell B, 902 is first determined by intersecting the effective area of ​​cell A with the rectangular band 903 of the twilight area around the line of equal intensity 904; then by intersecting the effective area of ​​cell B with the rectangular band 903; and then forming the union of these two areas, which are represented as the shaded area 905. The embodiment of Fig. 9 illustrates the determination of the handover area from cell A to cell B for the topological case of the embodiment of Fig. 2, in which the rectangular band 903 is well defined. In the topological case of the embodiment of Fig. 4, for which a similar rectangular band is not defined, the handover area from cell A to cell B is found as the intersection of the two effective cell areas, each of which may include extensions of either the either the first type or the second described above. For example, in the embodiment of Fig. 10, the effective cell area of ​​sector 1001 has been extended by an extension 1002 of the first type and the effective cell area of ​​sector 1003 has been extended by extensions 1004, 1005 and 1006 of the second type. Because this is a similar topological case to the embodiment of Fig. 4, the handover area from cell 1001 to cell 1003 is equal to the intersection between their two effective cell areas, shown as the area shaded 1007. It should be noted that the only difference between a handover area from cell A to cell B and a handover area from cell B to cell A, derives from the asymmetry of the penumbra area around the line of equal intensity, which occurs in the topological cases of the embodiments of Figs. 1 to 3.

As can be seen from the embodiment of Fig. 10, the handover area 1007 determined according to an embodiment of the invention herein is much smaller than the effective areas of the cell sectors 1001 and 1003. From this Thus, on average, a method according to an embodiment of the invention, which determines the handover area, is more accurate in locating a cellular device than prior art techniques that rely on locating only the cell sector.

An embodiment according to the invention also improves accuracy, on average, when the cellular network specifies the location of a cellular device using time advance data in addition to cell identifier data. FIG. 11 shows a corona sector 1101, which is used to model the estimated location of a cellular device in such a case, according to one embodiment of the invention. The additional time advance data restricts the location of the apparatus to a corona sector 1101 between two given radios 1102 and 1103 from an antenna 1104. It will be appreciated that the use of time advance data; or other possible data specified by a cellular network; that can narrow the modeled cell area, can be used consistently with embodiments herein - for example by modifying the model to determine the effective cell area. In this way, for example,

In the embodiment of Fig. 11, the cell area can be modeled as a corona sector, possibly extending to create an effective cell area in a manner similar to the techniques described herein. . Other shapes for cell areas may also be used in accordance with one embodiment of the invention. Regardless of the shape of the effective cell area, techniques according to one embodiment of the invention, on average, improve the location accuracy of a cellular device. Using the crown sector of Fig. 11, for example, a similar reduction rate in area can be obtained as when using full sectors as above.

Those skilled in the art will appreciate that the generalized parameters mentioned above (such as the parameters R1, R2, R3, R4, Cl, E1, E2, W1 and W2), can be determined empirically and calibrated in field tests. For example, tests can be performed in which the actual locations of cellular test devices are known, so that the actual locations can be empirically matched against cell mapping to determine suitable values ​​for the parameters. Parameters can be statistically estimated based on empirical results and can be improved as test results and other data accumulate over time. Another parameter can be used. Furthermore, a selection of the parameter mentioned above or completely different parameters can be used. Where cellular systems other than GSM are used, e.g. CDMA-based cellular systems, the embodiments can be modified e.g. so that the handover area is modeled as a different shape or set of shapes arising from the arrangement of cells in the active set.

According to one embodiment of the invention, a system and method for locating cellular devices can be used as part of a traffic information system, such as that described in US Pat. No. 6,587,781 to Feldman et al., A summary block diagram of which is shown in the embodiment of Fig. 12. In this system, the location of each of a plurality of mobile sensors on vehicles traveling on a road network 12 is determined, which has been analyzed to form an oriented road section network 14. Other sources of traffic information are they may or may not use to supplement mobile detection. The position data 62 is collected over time from the mobile sensors and periodically sampled by a sampler 1 for passage to a normalized travel time calculator 2. Based on the sampled data, the travel time calculator 2 determines an average normalized travel time value for each oriented road section of the network 14. A fusion and current imager 3 then use the calculated normalized travel times, as well as data obtained from other sensors, to generate a current image of the traffic conditions on the road network. A predictor 4 can then use the current image, as well as the rules from a pattern and rule generator 6, to predict traffic conditions or provide other information to a service engine 5, which can serve a variety of applications 7. Fusion and current imager 3 can merge data from a variety of sources, including normalized travel time calculator 2, fixed sensor traffic data 60, traffic data from traffic reports 64, and traffic data from other sources 66.

According to one embodiment of the invention, an apparatus for implementing the cellular device location technique, described herein, can be used to generate traffic data using cellular device locations from devices in vehicles. For example, when determining a handover area for a given cellular device, a traffic system may use the geographic area that corresponds to the handover area that has been determined, as an estimate of the location of a vehicle in which it was located. the cellular device at the time the handover event occurred. Based on the resulting position and time data for a large number of such vehicles and traffic data from other sources, a standard travel time calculator 2 or other traffic system component can generate a picture of driving conditions. traffic for a variety of uses, including predicting upcoming traffic conditions. In one embodiment, a technique according to those described herein for geographically locating a cellular device is implemented by the sampling module 1 of the embodiment of Fig. 12. The sampling module 1 is fed with position data 62, which they may include streaming data relating to cell handover events, from a cellular network. The position data 62 may include, for example, a cell identifier and time advance data of a cellular carrier; as well as vehicle position data from a variety of other mobile sensor sources, such as GPS data or other Fleet Vehicle Data. Vehicle position data 62 from each different type of mobile sensor source is sampled by its own adjusted sampling sub-module (included in a sampling module 1 of Fig. 12). Multiple sampling sub-modules can also be used to process different types of data from the same mobile sensor source. For example, separate sampling sub-modules can be used to process cell handover data and cell location server data.

Fig. 13 is a block diagram of an apparatus for locating cellular devices, according to one embodiment of the invention. This can be used, for example, in the traffic information system of the embodiment of Fig. 12. As summarized in the block diagram of the embodiment of Fig. 13, such apparatus 1305 for locating cellular devices may include an effective cell area module 1301 for determining cell areas; a twilight area module 1302 for determining the twilight area around the line of equal intensity; and a handover area module 1303 for determining the handover area. Apparatus 1305 for locating cellular devices can be implemented in a variety of different ways, as will be apparent to those skilled in the art.

ES 2 567 136 T3 technique after reading the techniques described herein. For example, apparatus 1305 may comprise a computer processor or specialized signal processing circuitry, which receives data 1300 on handover events or other cellular data, generated by a cellular network; and transmitting a resulting calculated handover area to a location-based application 1304; for example, the traffic information system of the embodiment of Fig. 12. Various steps of the method described in the embodiments herein can be implemented as routines in computer program code running on a computer processor 1305 or as equivalent specialized circuits for data processing.

Also, an apparatus according to an embodiment of the invention need not be implemented in the embodiment of Fig. 13. For example, two possible forms of implementation techniques herein are as follows (these examples are not intended to are limiting). In a first example, a cell map of a cellular carrier may be available for a system according to the invention. In this case, handover areas can be determined for all possible combinations of neighboring cells, based on cell correspondence, in an off-line process and stored in a database accessible by a system according to the invention. When cellular data flows into the system, the system uses the cell identifiers and / or timing advance data or other cellular network data for a given handover event to query the database (for example, using a table of search) and thereby obtain the relevant handover area. Thus, in the first example, the functions of the apparatus 1305 are performed offline and the data 1300 is subsequently processed online with reference to the handover data created offline by the module 1303. On the contrary, in a Second example, a cell mapping is not available to a system according to the invention. Instead, the system receives the geographic parameters of the cells involved in each handover event and calculates handover areas online based on the data flow, using, for example, the embodiment of Fig. 13. The modules 1301 -1303 of the embodiment of Fig. 13 they do not need to be directly correlated on different software modules; instead, the software may have equivalent functionality that implements a different or more complex architecture, as will be appreciated by those skilled in the art.

It will be appreciated that the embodiments admit a wide range of modifications without departing from inventive concepts. For example, one of ordinary skill will readily appreciate how the principles and benefits of the invention apply with various current and future frequency division multiple access (FDMA) and / or code division multiple access (CDMA) networks or other networks using access. Time Division Multiple (TDMA) in combination with the principles of FDMA and CDMA. Another less frequently mentioned alternative is polarization division multiple access (PDMA).

A skilled reader will also appreciate that, although the foregoing has described what is considered to be the best mode and, where appropriate, other embodiments of the invention, the invention should not be limited to specific apparatus configurations or method steps. described in this description of the preferred embodiment. For example, while various embodiments herein refer to geographically locating a "cellular device," it will be appreciated that this term should be broadly interpreted to refer not only to mobile cellular phones or other devices, but also, for example, to other devices. modules in communication with a cellular network, such as probes attached to vehicles, laptop computers, and specialist computer units that communicate with a cellular network. Those skilled in the art will also recognize that the invention has a wide range of applications, particularly location-based applications and services. For example, embodiments according to the invention can be used in a wide variety of applications to geographically locate a cellular device; including (but not limited to): location-based services, generally; traffic information systems; for emergency purposes, such as locating a cellular device that was used to call an emergency number; for escape planning; and for security, intelligence and national defense applications.