HK1050449A - System and method for measuring traffic flow - Google Patents

Description

System and method for measuring traffic flow

Technical Field

The present invention relates to a system and method for measuring traffic flow, and in particular to measuring vehicular traffic flow using existing mobile phones and networks.

Background

In recent years, the use of mobile phones has increased dramatically, with regular use accounting for a large percentage of the population in developing countries. There are many opportunities for providing services to users in addition to the usual communication services. Protocols such as WAP allow for the delivery of graphical and textual content to link to the internet. Whereby services and information can be provided. Among these services, the service for the new generation of hand-held portable (HHP) mobile phones is a Location Based Service (LBS). There are many services that make use of information on the location of a mobile phone and thus provide services to the user in some way.

The federal communications commission in the united states has decided that the network operator must be able to identify the location of a call within 400 feet (150m) of a call origination location over at least two-thirds of the time on day 1/10 of 2001. Making decisions effective over such a short time frame requires a formal management to be solved on a network basis (i.e., intelligent and precise positioning is not available on the handset). It is not always a welcome proposition to justify users upgrading their handsets, unless the network is willing to pay; of course, they would like to do so if it were less expensive to do so than if their network were upgraded. While network-based solutions are expensive for operators to deploy, they are cheaper to upgrade than all users, giving the background as if LBS in the united states were to be advocated, at least initially, using emergency 911 messages and will be network-based.

The focus in the non-U.S. market may be somewhat different. Although there is a regulatory requirement for LBS in the EU, the time frame is somewhat more relaxed; in 2008, the service must be in place. LBS have in fact been available in europe long ago, but are not normalized, mandatory as a commercial result.

Many services may be provided to customers based on location. Some of these services will be "unique points of sale" for next generation mobile communications, and their introduction is therefore commercially appreciated by network operators:

drawing

Emergency situation

Advertisement

Yellow pages

Local information

Security/tracking of stolen property

Fleet tracking

Telematic services

Traffic information (as per service director)

Location-based charging

Sailing along the shore

Weather of

Real-time public transportation information (Note: user and current information movement!)

Friend/employee finder

The accuracy of the position needs to be varied from one service to another and the required accuracy also affects the method of implementing the position detection.

Us patent 5,465,289 discloses a system for monitoring vehicular traffic. The system uses an additional radio receiver to detect the approximate location of the mobile phone by detecting handoffs between cell boundaries. Handoff is a signal transmitted between a mobile phone and a base station transmitter indicating that the mobile phone will communicate with a base station of a neighboring cell when moving from one cell to another. Additional radio receivers need to have the functionality to detect cell handoffs, store handoff records and detect and record geographical location data. However, the system cannot be applied to other systems than the first generation system, and cannot operate with a network-it is a stand-alone system.

Vehicle count and flow rate data is generated based on cell-to-cell hand-off and geographic location data. The in and out of cell handover usually occur at the same location on the highway. The hand-offs may be accumulated per unit time to estimate the vehicle count on a road. The time between the switch and the known travel distance allows a determination of a flow rate to be made. The geographic location of the vehicle over time may also derive the flow rate. In addition, the geographic location allows the handoff data to locate a particular road. Periodic reports are generated for these roads based on the monitoring.

Although providing useful services is disclosed in the system of' 289, it should be clear that there are many disadvantages. The system is accurate only to the size of the cell in the cellular network, which can be anywhere from 100 meters to 10 kilometers. Furthermore, existing systems are not suitable for providing location based services and therefore have further disadvantages.

Summary of The Invention

It is known to use a mobile telephone network to obtain traffic monitoring, but modifications are required. It is also known that a minimum modification should be maintained for the feasibility of such services.

Accordingly, there is provided a vehicle traffic monitoring system comprising a mobile telephone network, comprising a plurality of base stations for receiving and transmitting signals from and to mobile telephones, and a location monitoring unit for deriving the location of mobile telephones communicating via the mobile telephone network, the location monitoring unit comprising a memory for storing identification and location data for the plurality of mobile telephones, and a traffic flow analyser for determining the traffic flow at the location of the mobile telephones, wherein the memory and the traffic flow analyser are arranged such that the traffic flow can be determined substantially from the identification and location data only for a subset of the mobile telephones which have transmitted a traffic monitoring request to the mobile telephone network.

The invention offers the advantage that the analysis data for traffic monitoring are derived significantly from the mobile telephone carried by the traveling user and thus traffic information has already been requested. This reduces the errors that can occur from including sampled data from mobile phones that are not traveling in a road vehicle. Various weighting factors may be used to estimate traffic flow as those factors for HHP that are known in vehicles (requesting traffic information) and other aspects.

The invention also provides the advantage that a special role can be taken by a user receiving traffic information, by initiating a traffic monitoring request, and by reconfiguring the user's mobile phone when required. In particular, the mobile phones in each subset of mobile phones are arranged to broadcast a signal to the network more frequently than mobile phones not in the subset. The system is thus able to ensure that frequent location updates of mobile phones that are traveling and have "opted-in" to the traffic system are determined. This may be accomplished, as an alternative, by placing a flag on the user account in the network user database. This would allow the system to operate with a handset that does not change. Furthermore, it should be noted that the handset driven "opt-in" option can be implemented according to the "SIM toolkit", again without modification of the handset, as most handsets already support it.

In addition, the present invention resides in a mobile telephone adapted for use in a vehicular traffic monitoring system associated with a mobile telephone network, comprising: a radio unit for providing a processor and memory in telephonic communication with a mobile telephone network, the network including periodic update signals and signaling functions arranged to provide traffic updates, the traffic update signals function including an input for receiving a request from a mobile telephone user for traffic information and an output for causing the radio unit to broadcast an updated signal more frequently than usual.

Thus, a mobile telephone with such features cooperates with a traffic monitoring system to ensure accurate traffic flow. A user requesting traffic information automatically becomes a sample in the traffic flow statistics.

These and other inventive features are defined in the claims to which reference is made directly.

Brief description of the drawings

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 illustrates an embodiment of the traffic monitoring system of the present invention;

figure 2 shows functional components of a mobile telephone;

FIG. 3 shows key functional steps in operating a mobile phone in accordance with the present invention;

FIG. 4 is a flow chart of the main functions of a location monitoring unit embodying the present invention;

FIG. 5 is a flow chart detailing the course calculation of FIG. 4;

FIG. 6 is a flow chart detailing the travel speed calculation of FIG. 5; and

fig. 7 is a flow chart detailing the delayed notification of fig. 4.

Description of an embodiment

A vehicle traffic monitoring system is shown in fig. 1. Each portable (HHP) mobile telephone 1 communicates with a mobile telephone network 3 via a plurality of base stations 2. The network 3 and the base station 2 may be for any type of mobile telephony protocol and frequency. Such as GSM1900MHz, 900MHz or 1800MHz or new services such as UMTS. These and others are within the scope of the present invention. In addition, the embodiment comprises a location monitor 4, which analyzes the location of the mobile phone and derives traffic information as a result. The functionality provided by the location monitor will be described in detail later.

The geographical location of each mobile telephone 1 in communication with the network 3 may be obtained by the network 3 itself, the location monitor 4 or by a combination of both. Suitable methods of determining the position of a mobile telephone are well known to the skilled person and include phased array antennas at each base station to derive the angle of arrival of signals from the mobile telephone. This angle is used to give a position in comparison to angles obtained at other base stations. An alternative is to measure the time of arrival of a signal from a mobile telephone at a plurality of base stations, resulting in relative distance and hence position. These two alternatives require few if any changes to a mobile phone to measure location, but require some changes to the existing network. There are many other ways to obtain location data, all of which will work with the proposed system. The software required to implement the system may be distributed throughout the network; this would alleviate any privacy concerns since only one phone is moving from there to data passing outside a base station controller at this time, rather than specifically for the user.

A schematic diagram of key functional parts of a mobile phone is shown in fig. 2. A CPU10 provides the processing functions of the unit according to software control in the ROM20 and using a storage RAM 16. A display is here provided with an LCD12, and an input device, here a keyboard 14. A radio unit 18 provides RF transmit and receive functions and converts to and from voice data and RF signals. These functional components are known to the skilled person.

The processor 10, wireless unit 18 and memory RAM16/ROM20 are configured to provide the functionality of FIG. 3. In a typical HHP mobile phone, the radio periodically broadcasts location updates, typically every 30 seconds, or as one moves between cells. However, this is not sufficient for traffic monitoring purposes, and addressing by the traffic update signal function of fig. 3.

The traffic update signal function ensures that when a user requests traffic information, it is actually transmitted to the network and the user's HHP is reconfigured to transmit update messages more frequently than usual. The first step 30 is when the user selects the traffic information option. As a result, a signal requesting such information is sent to the network and an update is provided on the location of the HHP at step 31, using any of the geographical location methods described above. The user has in fact opted to participate in the system, as shown in step 32. If the user elects to opt-out of the system, the actions of step 33 are taken and the traffic update function ends at step 34. The mobile phone then returns to the normal state and broadcasts to the network in the normal manner.

When in traffic monitoring mode, a signal delay step 35 reduces the time between transmissions of update signals so that the HHPs send update signals to the network more frequently. An alternative within the scope of the invention is to not change the handset, but to change the network associated with the handset. The timing between location updates may be completely network driven; that is, the network will ask "where do you? "rather than waiting to be told" i am here ". This allows the network and traffic system to more accurately monitor the user's location and speed and also know that the user is more likely traveling in one vehicle. Analysis of such assisted position data will now be described in conjunction with fig. 4-7.

Fig. 4 shows the overall process on traffic monitoring according to an embodiment of the invention (diagram 1). The first step 40 is when the handset registers with the traffic monitoring system (handset option accept, fig. 3). The locations of the collections that have been reselected for participation are retrieved, at a get new location step 42. This location is stored in the location/event database 45 at the add new location step 44 and any "old" data is deleted under the control of a clock 47. The storage of the location at a given time allows the calculation of the most likely route at the calculate most likely route step 46, further shown in the graph 1a of fig. 5, described later. The average speed is then calculated at a calculate average speed step 48. The calculation of speed and position is referenced to a stored set of road maps 50. A confidence level is assigned as speed data and stored in a speed database 54 at a speed storage step 52, further shown in table 2 of fig. 6.

The steps up to this point allow the determination of the throughput conditions. Next, the handset is notified of local traffic conditions at notify handset step 56, further shown in table 3 of fig. 7. Finally, a variable delay is included in the process at wait step 58 as opposed to a handset speed before retrieving new location data for the handset and reporting the process.

The calculated most likely route for a given handset is shown in graph 1a of figure 5. A list of location and time data for a given handset is retrieved from the location/time database 45, step 60, where the current location is obtained. Possible routes are then retrieved from the road map set 50, at a calculate route step 62. If there is only one possible route, the confidence level is set high at step 64 (100). If there are many routes, the least squares difference calculation is performed at a least squares step 66. The trusted valve is set as a function of the least squares calculation at step 68. The trusted valve is adjusted in a calculate difference step 70 to account for the average speed of the handset in conjunction with a comparison to other identical routes with reference to an average travel speed database. As a result, the most likely route and level of trustworthiness occurs at step 46 for Chart 1.

Allowing statistical analysis of the routing data to provide traffic flow information, the route and confidence levels for each handset and the calculated speed of that handset are provided to a coarse speed and confidence level database 54 for further analysis, as shown in chart 2 of figure 6. The rough speed and confidence database contains the time of the speed and confidence data for each mobile phone entry at a given location, and the road segment. To process such data, data for a given road segment is first retrieved, at get data step 80. Data relating to the current traffic conditions is guaranteed, and data older than a certain number of minutes is deleted, at a delete data step 82. To further increase the data accuracy, a portion of the entries are ignored at an ignore entry step 84 to leave a given number or factor of entries belonging to a higher confidence level value.

The step for increasing the accuracy is also ensured in the ignore lowest percentage step 86, in which a given lowest entering percentage is ignored by the speed. This would eliminate users not in the car; this is particularly relevant if the opt-in is by way of an account option rather than by cell phone setting. The remaining entrants are thus correlated with the closest, higher confidence entrants having speeds more likely to approach the median speed on a given road segment. The average travel speed is thus calculated at an update average speed step 90 and provided to an average travel speed database 91 which provides data for calculating confidence rating values in fig. 5 (chart 1a) and for providing information to the user. Finally, the next road segment is retrieved in step 92 based on the re-performed calculation.

The resulting data may be provided to the user in various ways, as shown in FIG. 7 (Chart 3). If the user is making a request for information, as if moving from a HHP, the request is first used to reconfigure the HHP as previously described to send update data more frequently than usual, and to use the location information for that HHP to derive traffic conditions as already described.

As described above, the location of the HHP and the most likely current road are obtained at input step 100. The average travel speed database 91 is then queried at query database 102 and the handset can be determined at step 103 in conjunction with a reference to the type of received signal. If the handset is capable of processing graphics, an updated map is sent in step 104, if not, a SMS is sent if there is a delay in SMS step 106, or if the handset has an automatic answering capability, a short voice message describing the delay is sent.

Processing then continues on the network/location monitor to continue monitoring traffic flow conditions as long as the user remains "opt-in" to the system.

If the request is not for a mobile telephone user on a network, such as the internet, the get user request step 110 retrieves the data, which is provided at step 112 in the manner requested at step 114.

Although the system is described as separate network and location monitors, it should be clear that there is a logical division and that the location monitor functions may be performed by the network itself at one location or at distributed locations.

Claims (16)

1. A vehicular traffic monitoring system comprising a mobile telephone network including a plurality of base stations for receiving and transmitting signals from and to mobile telephones, and a location monitoring unit for deriving the location of mobile telephones communicating via the mobile telephone network, the location monitoring unit including a memory for storing identification and location data for the plurality of mobile telephones and a traffic flow analyser for determining the traffic flow at the location of the mobile telephones, wherein the memory and the traffic flow analyser are arranged such that the traffic flow is substantially determinable from the identification and location data only for a subset of the mobile telephones which have indicated a traffic monitoring request to the mobile telephone network.

2. A system according to claim 1, wherein the subset of mobile telephones are those mobile telephones which have transmitted a traffic monitoring request to the mobile telephone network.

3. A system according to claim 1 or 2, wherein the mobile telephones in each subset of mobile telephones are arranged to broadcast a signal to the network more frequently than mobile telephones not in the subset.

4. A system according to claim 1, 2 or 3 wherein the traffic flow is determined by configuring the traffic flow analyser to give a greater weighting to the location data of a subset of mobile telephones.

5. A system according to any of claims 1 to 4, wherein the traffic flow analyser is arranged to determine a level of confidence in the route for each mobile telephone in the subset.

6. A system according to claim 5 wherein the traffic flow analyzer is arranged to determine the flow of traffic as a function of the subset data having a higher confidence level.

7. A system according to any preceding claim, wherein the location monitor is arranged to determine the flow of traffic as a function of the subset data having the higher speed.

8. A traffic flow analyser as claimed in any one of the preceding claims.

9. A mobile telephone adapted for use in a vehicular traffic monitoring system associated with a mobile telephone network, comprising:

a radio unit for providing a processor and memory in telephonic communication with a mobile telephone network, the network including periodic update signals and signaling functions arranged to provide traffic updates, the traffic update signals function including an input for receiving a request from a mobile telephone user for traffic information and an output for causing the radio unit to broadcast an updated signal more frequently than usual.

10. A mobile telephone according to claim 9 wherein the traffic update signal function is arranged to cause the wireless unit to broadcast an update signal as a function of traffic flow data provided by the traffic monitoring system.

11. A method for monitoring vehicular traffic in a mobile telephone network, comprising obtaining locations of mobile telephones communicating via the mobile telephone network, storing identification and location data for each of a plurality of mobile telephones, determining traffic flow at the locations of the mobile telephones, wherein the step of determining traffic flow is determined transparently from the identification and location data of only a subset of the mobile telephones which have indicated a traffic monitoring request to the mobile telephone network.

12. A method according to claim 11, wherein the subset of mobile telephones are those mobile telephones which have transmitted a traffic monitoring request to the mobile telephone network.

13. A method according to claim 11 or 12, wherein the step of determining a traffic flow is performed by giving a greater weight to the location data of the subset of mobile telephones.

14. A method according to claim 11, 12 or 13, wherein the step of determining the flow of traffic comprises placing a function at a confidence level for each mobile telephone route in the subset.

15. A method according to any of claims 11 to 14, wherein the traffic flow of the step of determining the traffic flow is a function of the data of the subset having a higher confidence level.

16. A method according to any one of claims 11 to 15 wherein the flow of traffic in the step of determining the flow of traffic is a function of the data of the subset having the higher speed.