GB2416645A

GB2416645A - People presence estimation method

Info

Publication number: GB2416645A
Application number: GB0416467A
Authority: GB
Inventors: Abdol Hamid Aghvami; Paul Anthony Pangalos; Vasilis Athanasios Friderikos; Michael Dohler
Original assignee: Kings College London
Current assignee: Kings College London
Priority date: 2004-07-23
Filing date: 2004-07-23
Publication date: 2006-02-01
Also published as: GB0416467D0

Abstract

A method of estimating the number of people (36, 38, 40) within a predetermined range of a particular location, which method comprises the steps of:- <SL> <LI>(a) using an antenna means (18) to listen for electromagnetic communication signals indicative of the presence of one or more remote electronic data communication device (24, 26, 28) likely to be carried about the person of one or more of said people (36, 38, 40); and <LI>(b) providing an electronic output signal from said antenna means (18) representative of said presence; </SL> ```which electronic output signal facilitates estimation of the number of people (36, 38, 40) within said predetermined range.

Description

- 'V' ' 24 1 6645 - 1 -

PEOPLE PRESENCE ESTIMATION METHOD

FIELD OF THE INVENTION

The present invention relates to a method of estimating the number of people within a predetermined range of a particular location, to an electronic data communication apparatus, to a computer program and to a computer program product.

BACKGROUND OF THE INVENTION

Customer-related statistical information is very valuable to businesses.

Knowledge of the number of customers and potential customers in the vicinity of a particular location, such as a business premises or potential promotional location, is is an important piece of information. This enables the business to effectively target resources to periods when return on the investment is likely to be greatest.

Increasing numbers of people own electronic data communication devices such as mobile telephones, Personal Digital Assistants (PDAs) and notebook computers that are carried about the person substantially at all times. Furthermore an increasing percentage of these devices are being manufactured with some form of short-range wireless transmission capability e.g. Wireless Local Area Network (WLAN) and Bluetooth. Accordingly it is expected that in the future businesses will offer products and services to customers not only over the Internet and through business premises, but also through short-range wireless transmission portals such as WEAN Access Points and Bluetooth transceivers. At the priority date hereof businesses have already begun sending advertisements in the form of Short Message Service (SMS) text messages over the cellular network. I Iowever, such messages are not highly geographically limited in distribution so that a user may be some distance from the nearest physical location where the product or service can be obtained.

Short-range wireless transmission protocols offer businesses an opportunity to target services to customers in highly geographically limited areas e.g. radius of 10m 100m, and to research where is ideal for opening a shop in a new location or performing promotional activity. In order to tailor these services to the customer it is - 2 important to know how many people pass a particular location from where the service will be delivered, and what percentage of those people have devices (e.g. mobile telephones, Personal Digital Assistants, notebook computers) capable of accessing the new service.

Automatic gathering by computer apparatus of statistical information of the number of customers and potential customers passing a particular location, and of the capability of their electronic data communication devices, presents a technical challenge.

SUMMARY OF THE PRESENT INVENTION

Preferred embodiments of the present invention are based on the insight by the applicant that a short-range wireless communication protocol enables detection of passing electronic communication devices carried by users within a small geographical area, typically less than about 500m in radius. This can provide a means to estimate the number of people within that geographical area and to research locations for new business premises, promotions, etc. According to the present invention there is provided a method of estimating the number of people within a predetermined range of a particular location, which method comprises the steps of: (a) using an antenna means to listen for electromagnetic communication signals indicative of the presence of one or more remote electronic data communication device likely to be carried about the person of one or more of said people; and (b) providing an electronic output signal from said antenna means representative of said presence; which electronic output signal facilitates estimation of the number of people within said predetermined range.

Advantageously, step ( 1) comprises passively listening for said electromagnetic communication signals. One advantage of this is that no communication need take place between the antenna means and the remote devices. 3

Preferably, step ( I) comprises actively sending electromagnetic communication signals intended to cause any remote electronic data communication device within said predetermined range to respond. One advantage of this method is that it is more robust than the passive method. In particular, a remote device that can s be discovered will respond if within range.

Advantageously, the method further comprises the step of associating an electronic identifier with the or each remote electronic data communication device within said predetermined range, which electronic identifier helps to reduce the 0 chance of including the same remote electronic data communication device more than once in said estimate. In this way it is possible to remove a multiplicity of signals from one device during a listening period.

In one embodiment said electronic identifier is an address of an interface of each remote electronic data communication device at the physical layer or link layer.

Preferably this is a Bluetooth device address (BD_ADDR) that is included in the inquiry response message sent out by remote devices.

Preferably, step (a) is performed substantially continuously whereby the number of people within said predetermined range may be estimated substantially in real-time. Making data that represents the output signal available over a remote server, for example, enables numbers of people to be monitored in real-time.

Advantageously, step (a) is performed for a predetermined length of time and 2s is repeated periodically. This may help to save network resources.

Preferably, the method further comprises the step of interrogating each remote electronic data communication device to discover what services are available thereon.

The response from the remote devices may be stored in computer memory and/or transmitted to another computer for storage and analysis. A Service Discovery Protocol (SDP) may be used for this step, such as the Bluetooth SDP, Service I,ocation Protocol, Jini, and Universal Plug and Play. Greater Detail of these SDPs can be tound in "A Comparison of Service Discovery Protocols and Implementation of the Service Location Protocol", Bettstetter, C. and Renner C. in Proceedings of 6th 3s F,UNICE Open European Summer School: Innovative Internet Applications - 4 - (EUNICE), 2000.

Advantageously, said antenna means is in communication with an electronic data processing and storage means, the method further comprising the step of storing data communicated in said electronic output signal representing presence of said one or more remote electronic data communication device. In one embodiment the data processing and storage means is a notebook computer and the antenna means is provided therein. Alternatively the antenna means may transmit said output signal over a wired or wireless interface to a remote computer.

Preferably, the method further comprising the step of electronically storing data representing the time of detection of the or each remote electronic data communication device. By also storing data of when the remote device is no longer present it is possible to estimate the duration that each remote device stayed within the predetermined range.

Advantageously, the method further comprises the step of storing data representing an identity of said particular location and associating said one or more remote electronic data communication apparatus with said identity.

Preferably, repetition of said storage step generates in said electronic storage means a database of those remote electronic data communication devices within said predetermined range. This database may either be stored on a computer at the particular location or data may be sent to a remote computer where said database is generated.

Advantageously, the method further comprises the steps of electronically comparing entries in said database to determine those remote electronic data communication devices that have (a) just arrived within said predetermined range, (b) just left said predetermined range, and (c) still within said predetermined range, and storing data representative of said (a), (b) or (c). In this way the database may be kept substantially current whereby substantially real-time monitoring of the number of people may take place.

Preferably, said comparison step is performed by electronically comparing a - 5 first list of data obtained at a first time with a second list of data at second time earlier than said first time.

Advantageously, the method further comprises the steps of generating a s structured message comprising electronic data divided into fields representing data defined above, and forwarding said structured message to a remote computer means.

Preferably, the method further comprises the step of generating said structured message for each remote electronic data communication device discovered l o within said predetermined range.

Advantageously, said structured message comprises data representing more than one remote electronic data communication device. Thus the structured message may send all of the data in one message.

Preferably, the method further comprises the step of providing remote access to said database, whereby remote users may access said database to request retrieval of data therefrom. Access may be via a web page for example.

Advantageously, the method further comprises the step of generating and storing a plurality of databases providing said estimate for a plurality of particular locations. This may be done on a computer server that provides access to the databases over the Internet for example.

Preferably, said electromagnetic communication signals are used by a short range wireless communication protocol.

Advantageously, a radius range of said short-range wireless transmission protocol is less than approximately SOOm. 3(

Preferably, said radius range is less than approximately 300m.

Advantageously, said radius range is less than approximately I OOm.

Preferably, said short-range wireless communication protocol is Bluetooth - 6 and/or Wireless Local Area Network (WLAN) and/or Zigbee.

Advantageously, said particular location is a business premises. In principle the method may be applied to any location: stations, bus stops, theatres, restaurants, shops, cinemas, etc. It is not necessary for the location to be associated with a specific business or business premises.

According to another aspect of the present invention there is provided an electronic data communication device for use in an electronic data communication lo network, which electronic data communication device comprises means for storing and executing computer executable instructions for performing a method as set out above.

According to another aspect of the present invention there is provided an electronic data communication network comprising one or more electronic data communication device provided with computer executable instructions for performing a method as set out above. It will be apparent that different electronic data communication apparatus in the network can perform different steps of the method. Thus the method may be performed on computing apparatus that are distributed over a network such as the Internet.

According to another aspect of the present invention there is provided a computer program comprising computer executable instructions for causing an electronic data communication device to perform the method steps set out above.

According to another aspect of the present invention there is provided a computer program product storing computer executable instructions as set out above.

Advantageously, the computer program product is embodied on a record medium, in a computer memory, in a read-only memory, or on an electrical carrier signal. Part or all of the computer executable instructions may be stored on a server for download to one or more remote computer. - 7

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to provide a more detailed explanation of how the invention may be carried out in practice, a preferred embodiment relating to use with Bluetooth(g enabled devices will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. I is a schematic block diagram of part of an electronic data communication network operating using a method according to the present invention; 0 Fig. 2 is a schematic block diagram of an electronic data communication apparatus according to the present invention; Fig. 3 is a schematic block diagram of a remote electronic data communication device present in the network of Fig 1; Fig. 4 is a schematic block diagram of an electronic data processing and ] s storage apparatus according to the present invention; Fig. 5 is a flowchart of steps of a method in accordance with the present invention performed by the apparatus of Fig. 2; Fig. 6 is a schematic diagram of a structured message composed and sent by the apparatus of Fig. 2; and Fig. 7 is a flowchart of steps of a method in accordance with the present invention performed by the apparatus of Fig. 4.

Referring to Fig. I part of an electronic data communication network generally identified by reference numeral 10 comprises an electronic data communication apparatus 12 in the form of a notebook computer. The notebook computer 12 is located on a business premises such as a retail outlet or other environment accessible by the general public such as a theatre, restaurant, museum, etc. The notebook computer 12 is connected to the Internet 14 by means of a suitable network interface card (not shown in Fig. 1) by means of which applications run on the notebook computer may send to and receive data trom a remote electronic data communication apparatus in the form of a server 16 described in greater detail below.

The notebook computer 12 comprises a Bluetooth transceiver 18 (either separate e.g. with a commercially available USB Bluetooth) adapter, or integral) that is in electronic communication with a data processing system 20 in the notebook computer 12. The Bluetooth transceiver 18 enables the notebook computer 12 to communicate with other Bluetoothenabled devices that are within range, as shown schematically by the ellipse 22. Three electronic data communication devices 24, 26, 28 are shown within range of the Bluetooth transceiver 18. Each electronic data communication device 24, 26, 28 comprises a respective Bluetooth transceiver 30, 32, 34 by means of which each device may communicate with the notebook computer 12. Each electronic data communication device 24, 26, 28 is owned by a user 36, 38, respectively and may be in the form of a mobile telephone, personal digital assistant, notebook computer, etc. Referring to Fig. 2 the notebook computer 12 comprises a memory 42, a Central Processing Unit (CPU) 44, amplifiers 46, a display 48 (and an input means not shown e.g. keyboard), digital-signal processing (DSP) 50, radio control 52 and an antenna 54 (that make up the transceiver 18). The aforementioned parts are in electronic communication with one another. The antenna 54 provides for data to be transmitted and received by the notebook computer 12 using the Bluetooth communication protocol. The typical range over which the Bluetooth transceiver 18 can send and receive data is a radius of approximately lOm-lOOm (at a data transmission rate of 721kB s'), although this will very much depend on the transmission power of signals and the propagation channel around the transceiver 18.

Referring to Fig. 3 each electronic data communication device 24, 26, 28 comprises a memory 56, a Central Processing Unit (CPU) 58, amplifiers 60, a display 62 (and an input means not shown e.g. keyboard, touch-sensitive screen), digital signal processing (DSP) 64, radio control 66 and an antenna 68. The aforementioned parts are in electronic communication with one another. The antenna 68 provides for data to be transmitted to and received from the notebook computer 12 (and any other Bluetooth-enabled device nearby) using the Bluetooth communication protocol.

The devices 24, 26, 28 are carried by the users substantially at all times and are JO (usually) left powered on so as to receive incoming communications such as telephone calls and e-mails. In doing so each device will come in and out of range of the notebook computer 12 as a result of movement of the users 36, 38, 40 past or into the business premises where the notebook computer is positioned. The typical range over which the antenna 68 can send and receive data is a radius of approximately lOm-lOOm (at a data transmission rate of 721kB s'), although this will very much - 9 - depend on the transmission power and propagation channel around the transceiver.

Referring to Fig. 4 the server 16 comprises a memory 70, a Central Processing Unit (CPU) 72, amplifiers 74, digital-signal processing (DSP) 76, and a network interface card 78. The aforementioned parts are in electronic communication with one another. By means of the network interface card 78 applications running on the server 16 may send and receive data over the Internet to other computers, including the notebook computer 12.

When a Bluetooth-enabled device (in this case the notebook 12) wishes to discover other Bluetooth devices (in this case the devices 24, 26, 28) in range it enters what is known as an inquiry substrate. In this state the transceiver 18 broadcasts inquiry packets containing its device address (a 48-bit link layer address known as BD_ADDR). Each inquiry packet commences with an Inquiry Access Code (IAC) that may be one of two types: General Inquiry Access C.'ode (GIAC) and Dedicated Inquiry Access Code (DIAC). A GIAC is used when all devices in range are to be discovered and a DIAC is used when only certain specific devices are to be discovered. Since the notebook 12 wishes to discover all devices in range the inquiry packets that it broadcasts should use a GIAC. However, in some scenarios it may be that a user of the notebook 12 only wants to discover certain types of device in range.

In that case the appropriate DIAC should be used in the broadcast.

During the inquiry suhstate the notebook computer 12 generates a channel hopping sequence derived from the notebook computer's local clock and the GIAC that hops through 32 channels of the 79 available channels. Once the channel hopping sequence has been generated, the notebook computer 12 broadcasts inquiry packets on each channel defined in the hopping sequence.

Discoverable devices periodically enter what is known as an inquiry scan substate. In this state the transceiver of each device listens for inquiry packets on its inquiry scan channel. If an inquiry packet is received the device enters what is known as an inquiry response substate in which the device returns an inquiry response (Frequency Ilop Synchronisation - PHS) packet containing the BD_ADDR of the device that received the inquiry packet and the clock of that device amongst other things.

Thus in this way the notebook 12 can discover the Bluetooth device address BD_ADDR of each discoverable device that is within range. EIaving done this the notebook 12 does not have to proceed to any of the connection establishment substates as the minimum required information has been gathered from discoverable devices to enable an estimation of the number of people within range of the business premises to be estimated. More precise details of the discovery procedure are given in "Bluetooth Specification Version 1.2" (presently available to download from www.Bluetooth.com) to which reference is made.

It is not possible for the notebook 12 to passively discover devices in range by entering the inquiry scan substate because the inquiry packet (as defined in the Bluetooth Specification) does not contain the BD_ADDR of the sender. If this changes, or if another protocol is used in which devices broadcast data sufficient to resolve different devices (i.e. by means of some suitable identifier), then it is possible that the notebook 12 could passively discover devices in range by listening to the correct channel(s).

Stored in the memory 42 of the notebook computer 12 is a set of computer executable instructions that when executed perform steps of a method as shown in Fig. 5. At step Sl an integer t is set equal to zero; this integer provides a means to track the number of iterations of the method. At step S2 the notebook is caused to enter the inquiry substage for a duration of 25-30s whereby substantially all discoverable devices (i.e. those that actually enter the inquiry scan substate periodically) within range of the notebook's antenna 54 can be identified during that period. If a device is switched off or has been set by the user so as not to be discoverable then it will not be detected by the notebook computer 12. As described above the notebook computer 12 broadcasts inquiry scan packets and listens for FHS packets from discoverable devices. At step S3 the method repeats step S2 if no FHS packets have been received. If any FHS packets are received the CPU 44 extracts the BD_ADDR of each such device, records a time stamp of when the FHS packet was received, and caches this data in the memory 42 at step S4.

Assuming that devices are discovered at step S2, the step may be repeated immediately or there may be delay between scans to reduce overhead on network resources. It is possible for this delay to be adaptive for example as a function of the radius of coverage of the Bluetooth transceiver 18 and/or of the number of people estimated in a previous iteration. More frequent scans will increase the chances of discovering those devices that enter and leave the area of coverage very quickly.

Thus back-to-back scanning is ideal in terms of resolution, but this may place unacceptable overheads on the network.

Optionally at this stage the notebook computer 12 may interrogate the discovered devices to determine what services are available and to determine the 0 characteristics of those available service. In this connection reference is made to the "Service Discovery Protocol" (SDP) section of the Bluetooth Specification Version 1.2 mentioned above. A service is any device or application that can provide information, perform an action, or control a resource on behalf of another device or application. Sending a file between one network node and another, sending or exchanging business cards and providing means to establish a connection to a Bluetooth serial port are examples of services. A service may be implemented as software, hardware or a combination of software and hardware. An SDP client (located on the notebook 12 for example) sends requests for information about services to an SDP server on another device (such as one of the discovered devices).

The SDP server replies with SDP responses that included one or more service record, a service attribute and/or service class of services it has available. A service record comprises all information about a service that is maintained by an SDP server. The service record comprises a list of service attributes each of which describes a single characteristic of a service such as ServiceClassIDList and ProviderName. Each service is an instance of a service class. A service class provides definitions of all service attributes contained in that service record. Each service class is assigned a Universal Unique Identifier (UUID). Thus the notebook 12 may receive data representing a service record, a service attribute and/or a service class from discovered devices, and may store and/or forward this data to the server 16 where it may be stored for retrieval.

At step S5 it is determined whether or not t < I i.e. whether or not it is the first iteration of the method and therefore whether or not there is any data already stored in the memory 42 from a previous iteration. If is not greater than or equal to I it is assumed that this is the first iteration of the method either since the notebook was - 12 powered on or if t has been reset as described below. In this case the method proceeds directly to step S8 that is described in greater detail below.

If t is greater than or equal to I then BD_ADDR data must already be stored in the memory 42 from the previous iteration of the method. In this case the method proceeds to step S6 where the BD_ADDR data just obtained (i.e. iteration I) is compared to that obtained in the previous iteration (i.e. t - 1). At step S7 the comparison determines: (1) those devices that were present in both lists (i.e. those that are still within the predetermined range); (2) those devices that were present in lo the previous list but not in the current list (i.e. those devices that have left the vicinity of the business premises); and (3) those devices present in the current list but not in the previous list (i.e. those devices that have arrived near the business premises). A field is used to indicate (1), (2) or (3) in the BD_ADDR data.

At step S8 the notebook 12 composes a "structured message". Referring to Fig. 6 a structured message generally identified by reference numeral 80 comprises a BD_ADDR field 82, an ID field 84, a TIME field 86, a STATUS field 88 and a CHK field 90. For each BD_ADDR in the current list, the notebook 12 constructs a data payload comprising these fields. The BD_ADDR field 82 contains the 48-bit BD_ADDR of the particular device. The ID field 86 contains an identity of the business that has subscribed to the service. It may further include an identity of a particular business premises if the business uses more than one retail location. The TIME field 86 contains data representing the time stamp made when the FfIS packet was received. The STATUS field 88 whether the device falls into category (1), (2) or (3) above. The CHK field is an error correction field such as a checksum.

The structured message may be wrapped in an IP header and is sent to the network interface on the server 16 over the Internet 14 at step S9. The structured message can of course be sent using any suitable message format such as HTTP, SIP, etc. Alternatively the entire BD_ADDR list with all of the above fields of the structured message could be sent in a database format in one message or as an attachment to an e-mail message for example.

In this way the notebook 12 transmits all of the data in the BD-ADDR list to the server 16.

- 13 - At step S10 the notebook 12 purges the t - 1th data from the memory and at step S11 the notebook 12 sets t = l + I i.e. the next iteration. Finally the method returns to step S2 where the notebook is placed in the inquiry substate again.

Between step S 10 and step S2 there may be a predetermined wait period such that the number of discoverable devices is obtained every 30s, I minute, 2 minutes, or 5 minutes, etc. Alternatively the method may repeat continuously so that the only delay between inquiry scans is the time taken to process the 1th set of data as described above. The integer t may be reset if the wait period is particularly long e.g. greater lo than 5 minutes. This helps to ensure that devices do not appear to be present within the predetermined range longer than they actually are.

In this way the notebook 12 executing the aforementioned computer executable instructions is able to estimate the number of customers and potential customers from the number of Bluetooth-enabled devices near the business premises. By repeating these steps periodically the number of customers and potential customers can be monitored over time. Likewise the services available and the characteristics of these services can be discovered and recorded.

Stored in the memory 70 of the server 16 is a set of computer executable instructions that when executed perform steps of a method as shown in Fig. 7. At step S1 the server 16 awaits a structured message 80 prepared by the notebook 12. Upon receiving a structured message 80 the server 16 extracts the data at step S2. At step S3 the server 16 examines the ID field 84 of the structured message and searches the databases it already holds in memory for a database corresponding to that ID. Since the ID field of thestructured messages is used to identify each database, this step enables the server to determine whether or not there is a database already in existence for that ID. If there is no database the server 16 creates one at step S4. The database includes all of the fields of the structured message and each database is identified by the ID of the sender of the structured messages. If no database exists the method proceeds directly to step S5. At step S5 the server 16 examines the STATUS field 88 of the structured message. Depending on the value, the server 16 either: (a) Step S6: maintains the existing database entry for that BD_ADL)R since the device is still within the range of coverage of the notebook 12; or - 14 (b) Step S7: removes the database entry for that BD_ADDR since the device has been moved out of the area of coverage of the notebook 12; or (c) Step S8: creates a new database entry for that BD_ADDR since the device has moved into the area of coverage of the notebook 12. s

IIaving performed this procedure the server 16 contains a database of the most recent discoverable devices near the business premises and therefore an estimate of the number of customers and potential customers near the business premises. The database may also contain details of the services discovered as lo described above. Other parameters may be entered: for example the time stamp of when a device arrives and when the same device leaves can be used to record the amount of time a user of that device was near the business premises, the overall number of devices near the business premises can be recorded over time to give statistical data for that business over the last day, week, month, year, etc. The server 16 makes this statistical information available for viewing and/or download over the Internet 14. Suitable middleware enables a user to access a website and log on to their account giving access to the database representing their business premises. If the user owns more than one business premises it is possible that IDs of databases can be associated so that the user can see all of or a subset of the business premises they own. The middleware enables a user to view the data for the business premises in the form that they choose, for example traffic patterns over a given time period or in near real-time. The user may choose to view data of traffic patterns on a particular day at a particular time. For example it would be possible to view how many people came near the business premises each Saturday between 9 and 10am over the past year. Alternatively it would be possible to search historical data to determine the times when people stayed longest near the business premises or when there are peaks in number. The frequency and times at which particular users pass the location may also be recorded. Thus it will be appreciated that there are a very large number of ways to display and analyse data gathered in the manner described above.

Instead of or in addition to accessing a website the user may request a periodic update to be sent to them by e-mail for example. The update may include an attachment with data of the number of people passing the business premises over the last hour, day, etc. The server may also perform other functions including user subscription and authentication. T his may include storing the computer executable instructions described with reference to Fig. 5 and permitting them to be downloaded to a remote computer after any necessary payment and authentication.

In another embodiment the computer executable instructions shown in Figs. 5 and 7 may be provided in the form of one computer program comprising computer lo executable instructions for causing a computer to perform the steps of Figs. 5 and 7 without requiring communication of data over the Internet or other external network.

Of course it will be immediately apparent that in this case not all of the steps shown in Figs. 5 and 7 will be required to operate the method on a single computer. For example, steps S8 and S9 of Fig. 5 and steps Sl - S3 may not be required. Such computer executable instructions may be stored on a remote server for download over the Internet, or stored on a CD-ROM for sale for example.

It will also be apparent that the server 16 could carry out steps S6 and S7, and/or S8 of Fig. 5. In this way the notebook 12 would simply gather all inquiry response messages during the inquiry substate, form a structured message for each, and send each structured message to the server 16.

The method of the invention is not limited to Bluetooth-enabled devices.

Any short-range communication means such as Wireless Local Area Network (WLAN) and Zigbee may be used instead or in combination with the Bluetooth transceiver 18. In the case of WLAN for example the transceiver may be in the form of a separate Access Point that communicates with the notebook 12 either over a wired or wireless interface. Typical ranges of WLAN are: about lOOm radius at l IMB s' and 300m radius at IMB so. Typical ranges for Zigbee are between about l Om and I OOm at 250kbs-.

At the present time Bluetooth is preferred as increasing numbers of mobile electronic data communication devices such as mobile telephones and personal digital assistants (PVAs) are being manufactured with Bluetooth capability. These types of devices are easily carried by people as opposed to notebook computers, etc. - 16 that tend to be slightly more cumbersome. Therefore, the method of the invention is likely to give the most accurate picture of traffic near a business premises when searching for devices that are most likely to be carried by users substantially at all times i.e. mobile telephones and PDAs. It will be apparent that the method of the invention provides an estimate since of the number of people near a business premises since not everyone carries an electronic communication device, some devices are switched off, and other devices may have their short-range communication means disabled for example. Some users may even have more than one discoverable Bluetooth interface about their person.

Where other communication protocols are used it may be that it is not necessary for the notebook 12 to actively broadcast inquiry messages to discover nearby devices. If the protocol requires discoverable devices to transmit a beacon-like signal periodically it may be sufficient for the notebook 12 to listen on the correct frequency to obtain details of each discoverable device. Such methodology may be thought of as a "passive" type of discovery.

Any communication link may be used to send the structured messages between the notebook 12 and server 16 including a cellular network.

The method of the invention may be applied to research locations for promotional or other activities. For example a notebook computer 12 (comprising the computer executable instructions of Fig. 5) may be set up in a shopping centre to record the number of people passing that location over a given period. It is to be noted that the notebook 12 does not have to be in communication with the server 16.

The notebook 12 alone can perform all of the functionality and store the results in memory. This may be repeated at different points in the shopping centre to enable a business to determine where best to place a promotion for example. Once the promotion is underway the method provides an automatic way to monitor the success of the promotion as customer numbers can be automatically monitored throughout the promotion period and then compared to numbers beforehand.

At step S4 of Fig. 5 the notebook 12 may also measure and record a Received Signal Strength Indication (RSSI) for each device 24, 26, 28, and/or the name of the device (i.e. the uscrname that a user of the device has assigned). This data may also be stored and sent in additional fields of the structured message 80 to the server 16 where it may be stored in the database. The RSSI data may be used as an estimate of the distance of each discovered device from the Bluetooth transceiver 18 of the notebook 12. The RSSI might be compared to a threshold RSSI to ascertain the BD_ADDRs of those devices that are within a certain radius from the transceiver 18.

This enables devices that are deemed to be too far away to be ignored in the estimate.

For example, the transceiver 18 may discover Bluetooth enabled devices that are within a radius of approximately 100m. However, a business may only consider the number people within a radius of up to about 40m as of interest. Measuring the RSSI 0 of each discovered device provides a means to exclude those devices discovered between 40m and 1 00m from the estimate.

Although the embodiment of the invention described with reference to the drawings comprises computer apparatus and methods performed in computer apparatus, the invention also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice. The program may be in the form of source code, object code, a code intermediate source and object code such as in partially compiled form, or in any other form suitable for use in the implementation of the methods according to the invention. The carrier may be any entity or device capable of carrying the program.

For example, the carrier may comprise a storage medium, such as a ROM, for example a CD ROM or a semiconductor ROM, or a magnetic recording medium, for example a floppy disc or hard disk. Further, the carrier may be a transmissible carrier such as an electrical or optical signal that may be conveyed via electrical or optical cable or by radio or other means.

When the program is embodied in a signal that may be conveyed directly by a cable or other device or means, the carrier may be constituted by such cable or other device or means.

Alternatively, the carrier may be an integrated circuit in which the program is embedded, the integrated circuit being adapted for performing, or for use in the performance of; the relevant methods.

Claims

I. A method of estimating the number of people within a predetermined range of a particular location, which method comprises the steps of (1) using an antenna means to listen for electromagnetic communication signals indicative of the presence of one or more remote electronic data communication device likely to be carried about the person of one or more of said people; and (2) providing an electronic output signal from said antenna means lo representative of said presence; which electronic output signal facilitates estimation of the number of people within said predetermined range.
2. A method according to claim 1, wherein step (1) comprises passively listening for said electromagnetic communication signals.
3. A method according to claim I or 2, wherein step (1) comprises actively sending electromagnetic communication signals intended to cause any remote electronic data communication device within said predetermined range to respond.
4. A method according to any of claims I to 3, further comprising the step of associating an electronic identifier with the or each remote electronic data communication device within said predetermined range, which electronic identifier helps to reduce the chance of including the same remote electronic data communication device more than once in said estimate.
5. A method according to claim 4, wherein said electronic identifier is an address of an interface of each remote electronic data communication device at the physical layer or link layer.
6. A method according to any preceding claim, wherein step (1) is performed substantially continuously whereby the number of people within said predetermined range may be estimated substantially in real-time.
7. A method according to any of claims 1 to 5, wherein step ( I) is performed for - 19 a predetermined length of time and is repeated periodically.
8. A method according to any preceding claim, further comprising the step of interrogating each remote electronic data communication device to discover what services are available thereon.
9. A method according to any preceding claim, wherein said antenna means is in communication with an electronic data processing and storage means, the method further comprising the step of storing data communicated in said electronic output o signal representing presence of said one or more remote electronic data communication device.
10. A method according to claim 9, further comprising the step of electronically storing data representing the time of detection of the or each remote electronic data communication device.
11. A method according to claim 9 or 10, further comprising the step of storing data representing an identity of said particular location and associating said one or more remote electronic data communication apparatus with said identity.
12. A method according to claim 9, 10 or 11, wherein repetition of said storage step generates in said electronic storage means a database of those remote electronic data communication devices within said predetermined range.
13. A method according to claim 9, 10, 1 1 or 12, further comprising the steps of electronically comparing entries in said database to determine those remote electronic data communication devices that have (a) just arrived within said predetermined range, (b) just left said predetermined range, and (c) still within said predetermined range, and storing data representative of said (a), (b) or (c).
14. A method according to claim 13, wherein said comparison step is performed by electronically comparing a first list of data obtained at a first time with a second list of data at second time earlier than said first time.
15. A method according to any preceding claim, further comprising the steps of - 20 generating a structured message comprising electronic data divided into fields representing data defined in any of claims 9 to 14, and forwarding said structured message to a remote computer means.

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16. A method as claimed in claim IS, further comprising the step of generating said structured message for each remote electronic data communication device discovered within said predetermined range.
17. A method as claimed in claim 15, wherein said structured message comprises l o data representing more than one remote electronic data communication device.
18. A method according to any of claims 12 to 17, further comprising the step of providing remote access to said database, whereby remote users may access said database to request retrieval of data therefrom.
19. A method according to any of claims 12 to 18, further comprising the step of generating and storing a plurality of databases providing said estimate for a plurality of particular locations.
20. A method according to any preceding claim, wherein said electromagnetic communication signals are used by a short-range wireless communication protocol.
21. A method according to claim 20, wherein a radius range of said shortrange wireless transmission protocol is less than approximately 500m. 2s
22. A method according to claim 21, wherein said radius range is less than approximately 300m.
23. A method according to claim 21 or 22, wherein said radius range is less than approximately l OOm.
24. A method according to claim 20, 21, 22 or 23, wherein said shortrange wireless communication protocol is Bluetooth() and/or Wireless Local Area Network (WLAN). 3s - 21
25. A method as a claimed in any preceding claim, wherein said particular location is a business premises.
26. An electronic data communication device tor use in an electronic data s communication network, which electronic data communication device comprises means for storing and executing computer executable instructions for performing a method according to any preceding claim.
27. An electronic data communication device for use in an electronic data lo communication network, which electronic data communication device comprises means for storing and executing computer executable instructions for performing a method according to any of claims I to 17.
28. An electronic data communication device for use in an electronic data communication network, which electronic data communication device comprises means for storing and executing computer executable instructions for performing a method according to any of claims I to 19.
29. A computer program comprising computer executable instructions for causing an electronic data communication device to perform the method steps of any of claims I to 25.
30. A computer program product storing computer executable instructions in accordance with claim 29.
31. A computer program product as claimed in claim 30, embodied on a record medium, in a computer memory, in a read-only memory, or on an electrical carrier signal.