The present application is based on, and claims priority from, Taiwan Application No. 101124681, filed Jul. 9, 2012, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure generally relates to a method and system for estimating traffic information by using integration of location update events and call events.
In the past, the acquisition of traffic information relies on informing initiative of local police and the public, or issuing feedback of a global positioning system (GPS)-based vehicle probe (GVP) and a fixed vehicle detector (VD) device. In recent years, the research and applications of traffic domain use different collection methods and technologies such as vehicle detector, GVP, electronic toll collection (ETC)-based vehicle probe (EVP), and cellular based vehicle probe (CVP) technologies to perform detection of vehicular traffic parameter data.
Mobile users have advantages of the mobile spatial dimension and time dimension. Existing CVP traffic information collection technologies use the mobile phone as the detect tool of traffic information, to collect the transfer signaling between the mobile phone and the network system. And most technologies estimate the vehicle speed on the road through the location of handover events and the location update events, and the time difference between the handover events and location update events, wherein these events may occur when the road users dial/answer the phones.
In existing technologies, for example, a technology performs the road test through vehicle equipped with a GPS and a mobile communications module, learns recording location information occurred by call handover, and determines the travel distance between the locations of two handovers; and then the vehicle speed on the road is estimated only by the geographical location of a base station for a mobile phone occurring the handover. Another technology, for example, collects the mobile communication signaling for the users occurring location update at two location areas (LAs); and the vehicle speed on the road is estimated only by the geographical location of a base station for a mobile phone occurring the location update.
Another technology captures the A/Abis interface signal from a global mobile communications system network, analyzes the mobile communication signaling of the location area update and associates with a data mining method to estimate the traffic information of the end-user. Yet another technology is a technology of traffic information of 3G-based mobile communication network signaling. This technique uses the normal location update (NLU) and utilizes the selected handover (SHO) to calculate the vehicle speed on the road.
The traffic information obtained from the above techniques may produce quantity instability of the traffic information. For example, the number of valid samples obtained through two handovers is too small, or the time interval between samples through two location area updates is too long. And these techniques may also cause high cost for vehicle detectors' deployment and operation.
Therefore, under the existing collection policies for the traffic information, how to use the technology with a largest coverage of traffic information collecting, to provide the more accurate traffic information data to the road users, and to reach a driving environment with the better quality is a very important issue.
The exemplary embodiments of the present disclosure may provide a method and system for estimating traffic information by using integration of location update events and call events.
One exemplary embodiment relates to a method for estimating traffic information by using integration of location update events and call events, which is executed in a traffic information estimation system. The method comprises: associating location area update (LAU) and call sample data of at least one mobile user by using a sample capturing and analyzing device, wherein the sample data at least includes at least one LAU event of the at least one mobile user, and call arrival (CA) or call completion (CC) events of at least one call of the at least one mobile user; and based on the sample data, determining, by using a computation device, location information and time information of the at least one LAU event and the CA or CC events of the at least one call, and estimating, by using the computation device, traffic information of one or more designated roads according to the location information and time information.
Another exemplary embodiment relates to a system for estimating traffic information by using integration of location update events and call events. The system may comprise a sample capturing and analyzing device, and a computation device. The sample capturing and analyzing device is configured to associate location area update (LAU) and call sample data of at least one mobile user. The computation device, based on the sample data, determines location information and time information of at least one LAU event and at least one CA or CC event of at least one call, and estimates traffic information of one or more designated roads according to the location information and the time information.
The foregoing and other features and aspects of the disclosure will become better understood from a careful reading of a detailed description provided herein below with appropriate reference to the accompanying drawings.
Below, exemplary embodiments will be described in detail with reference to accompanying drawings so as to be easily realized by a person having ordinary knowledge in the art. The inventive concept may be embodied in various forms without being limited to the exemplary embodiments set forth herein. Descriptions of well-known parts are omitted for clarity, and like reference numerals refer to like elements throughout.
The disclosed traffic information estimation technique, according to the exemplary embodiments, collects the transfer signaling such as call and location area update, between the mobile user and the mobile network through a sample capturing and analyzing device, to perform road correspondence and association for the located cells (latitude and longitude) having the occurring events such as location area update (LAU) events and call arrival (CA) event (such as mobile originated (MO) event, mobile terminated (MT) event), or call completion (CC) event of any prior or posterior call, in order to increase the number of valid samples, and automatically estimate traffic information of one or more road sections. In other words, this technique combines with recorded base station's geographical location and time of the call events and the LAU events to estimate the traffic information, such as the vehicle speed on the road of road section (at the border of the mobile network area, and any designated road location in the area) and information for the road congestion, and further utilizes the estimated vehicle speed on the road to estimate information such as the travel time of the road section.
The “call” in the disclosure could be, but not limited to, voice call, connection, etc.
The most two kinds of occurred events of network signaling are call event and LAU event. The call event may include three kinds of events. When a mobile user starts a call, a call arrived (CA) event is produced. The mobile network side will record occurrence time and base station relevant information for the CA event. When the mobile user crosses communication range of the base station during a call, a handover event is produced. The mobile network side will record occurrence time and the base station relevant information for the handover event. When the mobile user ends the call, a call completion (CC) event is produced. The mobile network will record occurrence time and the base station relevant information for the CC event.
When a mobile user moves from one location area LA1 to another location area LA2, the mobile device such as a mobile phone, will inform the mobile network side through a location area update procedure. The mobile network side may record the occurrence time of the location area update event and the sequence moving from LA1 to LA2 for the mobile user. The disclosed exemplary embodiments may use at least one LAU event and call arrival (CA) event or call completion (CC) event of mobile originated/mobile terminated to perform sample association, in order to increase the number of valid samples; and select the associated samples according to the records of the cells (performing road correspondence) and occurrence time of at least one occurred event, to increase road range and availability for promoting the traffic information applications.
Accordingly, the disclosed exemplary embodiments may determine the road congestion by associating LAU events and CA or CC events that are induced by the mobile device. For example, when the number of occurring the LAU events is greater than a first threshold value (or called the location update threshold), and the number of occurring the CA events and CC events before crossing the location area border or the number of occurring the CA events and CC events after crossing the location area border is greater than a second threshold value (or called the CA+CC threshold), the exemplary embodiments may issue a road congestion warning. The principle of determining road congestion according to the exemplary embodiments is that when road congestion occurs, the number of LAU events crossing the location area border is larger, and the number of CA or CC events for the road users is also larger. In other words, road congestion or not may be detected through the CA+CC threshold of the roads before or after crossing location area border and the location update threshold.
In the exemplary embodiment of
The aforementioned three values of statistics data may be compared with the actual vehicle speed detected by the vehicle detector.
As shown in
Accordingly,
According to the disclosed exemplary embodiments, the sample capturing and analyzing device may select data of the mobile users to obtain LAU events and prior/posterior call events of the mobile users through a mobile originated/mobile terminated (MO/MT) cell information database. With a time interval of two prior/posterior events and a base station distance of these two events kept in the database, it may estimate one or more samples such as the vehicle speed on the road of front and behind designated areas of designated roads, travel time, etc. The traffic information estimation method may further use the mobile originated/mobile terminated cell information database to establish historical data of location update cell groups for at least one mobile network (for example, 2G or 3G mobile network) of the one or more designated roads, and establish historical data of the mobile originated/mobile terminated cell of the at least one mobile network for front and behind designated areas of the one or more designated roads.
According to the disclosed exemplary embodiments, the traffic information estimation method may further use a resident user filtering module, and the resident user filtering module may determine whether there is at least one resident user in the at least one mobile user, and then filter the sample data of the at least one resident user to obtain a valid sample collection, by using the historical data of the at least one mobile user, such as the base station data of the mobile user, geographical information system (Geographic Information System, GIS) information of to-be-tested roads, the traffic historical data of the mobile location update's information, MO/MT traffic historical data, etc. In the disclosure, a resident user may be defined as a user that has stayed at the range covered by a same group of mobile cells for more than a time unit, for example, a user that has stayed at the range covered by a same group of mobile cells for more than a location update period (such as an hour).
The samples that have been filtered the resident users may be filtered again via one or more selecting sample methods to obtain valid samples. The selecting sample methods may be such as the average standard deviation filtering method, the road speed limit filtering method, the percentage filtering method, the backtracking average standard deviation filtering method, road diverged event filtering method, historical difference filtering method, the law of large numbers filtering method, etc. The valid samples may be through road valid information estimation method and integrated with different mobile networks (e.g. 2G and 3G network) data to obtain traffic information such as the vehicle speed or the road section travel time, and so on. The road valid information estimation method may use such as methods of mean, mean of previous modes, weighted mean, maximum, median, mean of modes, geometric mean, harmonic average, historical weighted mean (the arithmetic average of current data and n weighted pervious historical data), and so on. Similarly, the samples that have been filtered resident users may also be used to detect road congestion via the above-mentioned NLU threshold (i.e. the threshold of the number of the LAU events) and the CA+CC thresholds of the roads before and after the border.
As mentioned earlier, the disclosed exemplary embodiments may perform sample association by using at least one LAU event and CA or CC event, and perform road correspondence via the cells having occurred the recorded events.
The method further filters out a valid sample set by estimating a vehicle speed of the vehicle that the mobile user of each sample in the calculable sample set is in, and checking if the estimated vehicle speed is within a predefined range, such as within a maximum road speed and a minimum road speed, on the one or more designated roads (step 1240); and automatically estimates traffic information on the one or more designated roads based on the valid sample set (step 1250). The estimated traffic information may be, for example, the road speed estimation and the congestion estimation of the one or more designated roads, and the travel time of road sections of the one or more designated roads. In other words, the method filters out a valid sample set based on the vehicle speed of the vehicle that the mobile user of each sample in the calculable sample set is in, and further utilizes the valid sample set to estimate the traffic information on the one or more designated roads.
The disclosed exemplary embodiments may increase the number of valid samples by the road correspondence and the sample association, and automatically estimate the traffic information of the road sections. The road correspondence indicates that an appropriate distance between a road and a mobile cell within a mobile cell coverage range is selected for an occurred event (LAU or mobile originated), and the appropriate distance may correspond to one location point on the road.
Referring to
Take the direction positioning method as an example. The method finds the location and the antenna azimuth of each cell from a mobile base station database, and finds the GPS coordinates of the intersection of each cell along the azimuth and the straight line of the road as the corresponding road location point.
According to the data analysis and computation results of the aforementioned method, the disclosed exemplary embodiments of the traffic information estimation method may further provide to a media release interface (such as websites or navigation industry) to publish the traffic information of location update border's road section, such as vehicle speed information (such as vehicle speed of the designated road section), travel time information and road congestion information, and so on.
Accordingly,
The mobile originated/mobile terminated (MO/MT) cell information database 1512 may be established as follows. A mobile information capturing module 1514 in the sample data system 1510 first collects the mobile user information (for example, base station information 1514a, tested road GIS information 1514b, mobile location update traffic historical data 1514c, MO/MT traffic historical data 1514d, etc.), then automatically learns to establish the MO/MT cell information database for one or more designated roads of location area update, and to publishes the traffic information. Therefore, it may create and save the historical data of the location area update cell group for at least one mobile network (such as 2G or 3G mobile network, etc.) of one or more designated roads, and also create and save the MO/MT cell historical data for the front and behind designated areas of the one or more designated roads in the mobile originated/mobile terminated (MO/MT) cell information database 1512. These historical data may be for selecting and filtering usage of follow-up data. The historical data of the location area update cell group for at least one mobile network of one or more designated roads and the MO/MT cell historical data for the front and behind designated areas of the one or more designated roads may be established in the backend sample data system 1510 offline.
The traffic information estimation system 1500 may further include a resident user filtering module 1506 to determine whether there is at least one resident user, and then filter the sample data of the at least one resident user, so as to obtain a valid sample set1506a. The details have been described in the aforementioned.
The computation device 1504 may select valid samples by filtering again the valid sample set1506a that has been filtered by the resident user filtering module 1506, via one or more times' selecting sample methods (the usable selecting sample methods as previously described). The computation device 1504 may further integrate with different mobile intra-network (e.g. 2G and 3G network) data to estimate traffic information such as the vehicle speed on the road or the road section travel time, and so on. As mentioned above, the road congestion may also be detected via the above-mentioned NLU threshold (i.e. the threshold of the number of the LAU events), the CA+CC thresholds of the roads before and after the border, and comparing with the valid samples. The computation device 1504 may also provide, such as a media release interface 1508 to publish the estimated traffic information of location area update of border sections.
The computation device 1504 may also calculate vehicle speed and road section travel time by predefining and adjusting one or more filter parameters and one or more sampling parameters. The filter parameter such as the road speed limit, represents estimating the reasonable shortest and longest travel time as the filtering conditions. The sampling parameter such as sampling percentage of samples, represents sampling suitable samples according to a defined sampling percentage, to calculate the road section travel time. Example of the process to predefine and adjust filter parameters and sampling parameters is described below. The process uses the predefined filter parameters and sampling parameters to calculate the road section travel time; then adjusts filter parameters and sampling parameters, and calculate the road section travel time; then compares the travel time of before adjustment and after adjustment; accordingly, re-adjusts these parameters until the best parameter has been set. The adjustable range of road speed limit may be, for example, the fastest road speed limit is 40 to 80 kilometers per hour, and the slowest road speed limit is 5 to 30 kilometers per hour; and the adjustable range for sampling percentage is such as 10% to 50%.
Therefore, the disclosed exemplary embodiments provide a method and system for estimating traffic information by using integration of location update events and call events. The technology collects transferred signaling between the mobile phone and the mobile network system through a mobile network signaling capturing and analyzing device. The mobile network signaling may include call events and location area update (LAU) events. The exemplary embodiments perform road correspondence and association to at least one LAU event and at least one event for the cell (latitude and longitude) of any prior/posterior mobile originated (MO), mobile terminated (MT) or end of call, to calculate the traffic information of the road sections, such as the vehicle speed (between the mobile network area border and any designated road location in the area), the congestion estimation, the road section travel time, and so on.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.
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Number | Date | Country | |
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20140011484 A1 | Jan 2014 | US |