Method and system for determining the number of cell phones in a chosen area and use of the method

Field

The invention concerns a method and system for determining the number of cell phones in a chosen area. By assuming that on average every person carries one cell phone that sends out a signal and is thus detectable, or by using another assumption on the number of people that carries a cell phone that may or may not be based on investigations thereof, the method allows the number of people in a chosen area to be counted. The invention also relates to the use of the number of cell phones counted in a chosen area.

Background

It is often desirable to know how many people are present in a certain area at a certain moment of time, for example on a day that there is a special event in a city, the police and emergency services would benefit greatly from knowing how many people there are in the city, and they would also benefit from having a better knowledge on where they are.

State of the art is to monitor the number of people entering a certain area by cameras.

Modern cameras and image processing techniques allow the images of the camera to be translated into a number of people passing by the camera at a certain moment. By placing cameras on several locations and processing the data gathered by these cameras, the number of people present in a certain area can be determined.

However, cameras are expensive, and the use of cameras is undesirable from a privacy point of view because people can be recognized from camera images. Cameras are also often vandalized.

Description of the invention

The aim of the invention is to provide a method without the disadvantages mentioned above.

The invention relates to a method for determining the number of cell phones in a chosen detection area, comprising

placing at least one device suitable for the detection of signals from cell phones in the chosen area - detecting said signals counting of the number of different signals detected - optionally saving the information on the number of signals counted on a device for data storage optionally transmitting the information on the number of signals counted to a computer or computer network.

Each cell phone sends out a signal that is unique for that cell phone and thus allows the counting of that cell phone only once, even though the cell phone sends out more than one signal over the time period that the method according to the invention is carried out for. Thus, in the method according to the invention a signal is only counted when it is different from a signal already counted.

It is an advantage of the method according to the invention that only the presence of cell phones is detected. The persons carrying the cell phones can remain anonymous.

It is also an advantage of the method according to the invention that cellular phones are easy to detect and the method according to the invention requires limited investments.

By assuming for example that on average every person carries one cell phone that sends out a signal, and thus is detectable, the method allows the number of people in a chosen detection area to be calculated.

For the purpose of this invention, the terms cell phones and mobile phones are used interchangeably. The term "cell phones" and "mobile phones" also cover all other devices with which phone calls can be made without using a land line , such as personal digital assistants (PDA's) and the like. Cordless phones that have a base station located in a fixed place and that are typically used indoors and making connection with other phones through a landline are not considered to be mobile or cell phones in the context of this invention.

Devices detecting the presence of a mobile phone are known. Providers of telecom services use so-called Base Transceiver Stations (BTS) to detect the presence of cell phones of their clients. A Base Tranceiver Station typically comprises three antenna's that each cover 120° . Thus, each BTS covers a circular area surrounding the BTS and can detect signals send by mobile phones in that area. However, for the method according to the invention, the detection area need not be circular, and hence, it can also be carried out using only one antenna.

In an embodiment of the method according to the invention, the device used for the detection of a cell phone is a Base Transceiver Station. Using Base Transceiver Stations has as advantage that they are present already on very many locations. However, each telecom service provider uses its own network of BTS' s and thus, only the number of mobile phones using the providers whose BTS 's are used will be detected. If the market share of a certain provider is known, this still allows the number of phones and thereby the number of people to be estimated. However, the accuracy may be less than when each mobile phone is actually detected.

Other devices for detecting the presence of mobile phones are also known. For example, the CAA - Cellular activity analyzer is known. The CAA is a smart cellular detector, based on a modified Toshiba hand held computer. The CAA has been designed to detect active and dormant hidden cellular phones, including cellphone-based bugging devices, and measures all communication activity in a given area. By using pattern-matching technology, the CAA is able to differentiate between signaling activity such as SMS messages sent or periodic registration updates generated automatically by the GSM phone, and actual voice or data calls. Whenever cellular transmission is detected, the CAA provides the user with real time audio and visual alerts, as well as the following information:

- Exact time stamp

- Detected cellular system indication (GSM, TDMA, etc.) - Duration of conversation

- Indication of cellular registration/ SM

- Display of detected cellular signal strength, enabling user to estimate the distance of the hidden mobile phone.

The CAA creates a report of cellular activity that took place during a certain period of time, as defined by user. This report can be easily synchronized to an MS Word document, providing the user with a professional report including precise data: were there any cellular-based eavesdropping attempts, when did each attempt take place, estimated location of the cellular-bugs, and more.

In all the known uses of the CAA and other devices detecting the presence of mobile phones, it is the actual detection of the mobile phones and their use patterns that are of interest. Devices detecting the presence of mobile phones are typically used to detect if a phone is present in an area where there should be no mobile phone present, such as in a prison or police investigation room, or in a class room where exams are being taken. So far, the use of this type of devices has not been applied for counting the number of mobile phones.

The known devices for detecting mobile phones use one or more ways of indicating the presence of a mobile phone, such as for example light signals, sound or text signals. Any of those signals can easily be counted, either by a person or by known devices. Preferably the method according to the invention allows the number of signals of mobile phones detected to be counted by a device.

If a device for data storage is used in the method according to the invention, it may be any device suitable for storing the data generated. Thus, the data storage device may be suitable for storage of text data, sound data, images, etc. Preferably all data are digital data that may be further processed by a computer.

The invention also relates to a system for determining the number of cell phones in a chosen detection area, comprising at least one device suitable for the detection of signals from cell phones in the chosen area, and means for counting the number of signals detected.

Means for counting the number of signals detected can be any means suitable for counting the type of signals generated by the detection device, preferably the means for counting are in communication with a computer or computer network, so that in the end the number of mobile phones can be read from a display or paper printout generated by the computer.

There are various types of mobile phones in use to date. All of these send out signals. Although for example GSM phones do not send out signals continuously, the signals are

being sent out with such a high frequency that the phones will be detected even when the detection area is relatively narrow and the mobile phone is carried by a person walking through the area. Moreover, in case mobile phones would not very frequently send out signals, all mobile phones can still be detected by making the detection area so large that in the time a phone is present in the area it will always at least once send out a signal.

Each mobile phone sends out a signal that is unique for that mobile phone. Known detection devices can distinguish signals that have been sent out by different mobile phones.

Thus, by carrying out the method according to the invention over a period of time longer than the longest interval known to be used by a mobile phone to send out a signal, all mobile phones in the detection range of the detection device can be identified and thus counted. When the detection device used is limited to the detection of mobile phones using a certain provider, the number of phones can still be calculated by using information on the market shares of various telecom service providers.

Thus, the invention relates to a method for counting the number of people in a chosen detection area by determining the number of cell phones in a chosen detection area comprising the steps of placing at least one device suitable for the detection of a signal from a cell phone in the chosen area detecting said signals - counting of the number of signals detected correlating the number of mobile phones to the number of people in a certain area by using information on the market share of the mobile phones detected by the device used or by using a calculation rule based on other information.

At the moment various types of networks for mobile phones are known, such as for example GSM (2 Giga hertz), GPRS(2.5 Giga hertz), UMTS(3 Giga hertz), HSDPA (3.5 Giga hertz). The method according to the invention can be used for any type of network, provided the detection device is suitable for detection of mobile phones operating at a certain frequency.

By choosing the location and number of devices, the area in which the number of cell phones is to be counted can be chosen to fit any desired shape. Thus, it is possible to place one device in an area, for example a street, and count the number of cell phones present in the detection range of the device. By using this set up the number of cell phones present in the detection area on a giving moment becomes known. By continuously carrying out the method over a certain period of time, the number of cell phones present in a certain area over that period of time becomes known. It is also possible in the method of the invention to place two devices. Using one or two device's does not allow the exact localization of cell phones, but it does allow the counting of cell phones in a chosen detection area.

It is also possible in the method according to the invention to place three or more devices suitable for the detection of a signal sent out by a cell phone. It is well known that by triangulation the exact position of a given cell phone may be determined. This is sometimes used by the police as evidence that a certain person was in a certain area at a certain time. Another known use of a triangulation system is the use of in a system that triangulates the location of each driver (assuming each driver carries a cell phone) by monitoring the signal that is handed of from one cell tower to the next. In that system each phone is uniquely identified and the information is compared with a highway map to record which road each driver is travelling at. Thus, the method is used to follow the flow of traffic, and it is not aimed at counting the number of people by counting the number of cell phones.

In a preferred embodiment a detection device is used which is direction sensitive, i.e. which does not have a circular detection range but a detection range that is more oblong in shape.

The invention preferably relates to uses of the method wherein only the number of cell phones that is present in a chosen detection area is used i.e. use wherein it is irrelevant who the persons are that carry cell phones that send out signals. Thus, it relates to the use of the method according to the invention to determine the effect on the number of people present of a certain event taking place in a town, village or other specific area, such as for example a shopping centre. By measuring the number of people present before the event, preferably by measuring this number on various occasions before the event, and by measuring the number of people present during the event, the number of people present because of the event may be estimated. The method

also allows the connection of various types of information to the numbers of people as represented by the number of cell phones, e.g. information on the weather or information on other event taking place, for example if an important football match is taking place during the time the number of cell phones in a certain area is monitored, etc. By combining these types of data the success and/or effectiveness of events can be monitored.

The method according to the invention may also be used to control the number of people present in a certain area, by using the information on the number of people present in the chosen detection area as input for a system controlling the entrance or additional entrance of a number of people to the area. For example, gates can be controlled to control the number of people entering and/or leaving a certain area.

The invention also relates to the use of the method according to the invention to determine the number of cell phones in an area and the number of cell phones in the same area during the time of road construction. Such information is useful for example to calculate the turnover lost by enterprises located at or in the vicinity of road construction projects.

The invention also relates to the use of the method according to the invention for determining the number of people present over a certain time in an area where an advertisement is placed. This information may be used to determine the selling price of advertising space in public places or for taxing advertisements in public places. .

Using the detection of cell phones present in a certain area over time makes it possible to detect trends in time.