Optimization of terminal geolocation based on identifiers of one or more nearby transmitters.

Abstract

The invention relates to a method for geolocating a terminal (20) of a wireless communication system (10), wherein the terminal detects, for at least one originating device (40), an identifier (ID3) of the originating device. The terminal performs a lossy compression of the identifier of the originating device to obtain a shortened identifier (CID1) and then transmits this shortened identifier in a message to the access network. The access network is able to disambiguate the identifier of the originating device on the basis of the shortened identifier, identification information (Info3) disambiguated on the basis of the received message and an ambiguity resolution database (33) capable of creating a number of lists of identifiers of the originating device, each list being associated with a different value of the identification information. The geolocation of the terminal can then be estimated on the basis of the identifier of the originating device and with the aid of a geolocation database (51) storing the list of identifiers of the originating devices and the respective geolocations of said originating devices.

Description

Technical Field

[0001] The present invention belongs to the field of determining the geographical location of terminals in a wireless communication system. The determination of the geographical location of a terminal is implemented using a geographical location determination server that includes a database for associating one or more identifiers of neighboring transmitting devices detected by the terminal with the geographical locations of the transmitting devices.

Background Art

[0002] Currently, there are several geographical location determination systems based on a database that associates identifiers of transmitting devices (such as WiFi or Bluetooth access points, or RFID tags) with the geographical locations of the transmitting devices.

[0003] In such a geographical location determination system, for at least one transmitting device, the terminal detects the identifier of the transmitting device based on a message transmitted by the transmitting device, for example, a beacon signal. Next, the terminal sends an inquiry message to the geographical location determination server. The inquiry message contains the identifier of the transmitting device. The geographical location determination server includes a geographical location determination database that associates the identifier of the transmitting device with its respective geographical location. Therefore, the geographical location determination server can identify the geographical location associated with this transmitting device, and then send this information to the terminal in a response message. The geographical location of the transmitting device corresponds to the estimated geographical location of the terminal.

[0004] The geographical location of the terminal may be refined according to the power level of the beacon signal received by the terminal. It is also possible to estimate the geographical location of the terminal according to the geographical locations of a plurality of different transmitting devices from which the terminal has received beacon signals at a predetermined time.

[0005] In some cases, it is important to limit the energy consumption of a terminal and / or the radio resources required for the terminal to send query messages. This is especially true when communication between the terminal and the geolocation server is conducted over a low-speed, low-power extended access network (Low Power Wide Area Network, or LPWAN). Such wireless communication networks are particularly well-suited for applications such as IoT (Internet of Things) or M2M (Machine to Machine) communication.

[0006] Therefore, we can consider limiting the number of caller identifiers included in the query message, or compressing the caller identifiers included in the query message to limit the size of the query message.

[0007] However, limiting the number of caller identifiers included in the inquiry message can lead to a decrease in the accuracy of the terminal's geolocation.

[0008] Compressing the caller identifier included in the query message may lead to ambiguity in the terminal's geolocation (in the case of lossy compression) because the compressed identifier may match multiple identifiers in the geolocation server's database. If the approximate location of the terminal is known, this ambiguity can be considered by limiting the geographic area over which the compressed identifier is being matched with the caller identifier. However, the approximate location of the terminal cannot always be obtained.

[0009] Therefore, a satisfactory solution is needed that limits the energy consumption and / or radio resources required for the terminal to send query messages while maintaining sufficient accuracy in the terminal's geolocation. Geolocation servers and access networks are typically managed by separate operators. Furthermore, it is preferable that the adopted solution does not require any modification of the interface with the geolocation server. [Overview of the project] [Problems that the invention aims to solve]

[0010] The present invention aims to improve upon all or some of the shortcomings of the prior art, particularly those mentioned above, by proposing a solution that optimizes the determination of the geographic location of a terminal based on one or more identifiers of nearby transmitters, from the viewpoint of energy consumption, and / or the use of wireless resources, and / or accuracy. [Means for solving the problem]

[0011] To that end, the present invention proposes a method for geolocating a terminal of a wireless communication system according to a first aspect. The terminal is adapted to exchange messages with the access network of the wireless communication system according to a first wireless communication protocol. This method is - For at least one transmitting device, a step of detecting the identifier of the transmitting device at the terminal based on a message transmitted by the transmitting device in accordance with a second wireless communication protocol, - The process of obtaining the shortened identifier of the transmitting device at the terminal by irreversibly compressing the identifier of the transmitting device, - The process of sending a message containing the abbreviated identifier of the transmitting device to the access network from the terminal, - An ambiguity resolution database capable of creating multiple lists of abbreviated identifiers, identification information clarified based on messages transmitted by terminals, and identifiers of transmitting devices, wherein each list is associated with a different value of the identification information, and the process of clarifying the identifier of a transmitting device based on this ambiguity resolution database. - A process of estimating the geographic location of a terminal based on the identifier of the transmitting device, and using a geolocation database that stores a list of transmitting device identifiers and the geographic location of each of these transmitting devices. Includes.

[0012] The geolocation database is stored on the geolocation server, while the ambiguity resolution database is stored on one or more servers separate from the geolocation server. For example, the ambiguity resolution database is stored on one or more servers on the access network, or on one or more third-party servers connected to the access network.

[0013] In the following explanation, the term "identifier" refers to the identifier in its full form (i.e., the unabbreviated form). The term "abbreviated identifier" refers to the abbreviated form of the identifier obtained through irreversible compression of information.

[0014] By performing lossy compression on the transmitter's identifier, it becomes possible to obtain identifier information in a reduced size. This reduces the size of messages containing identifier information transmitted by the terminal to the access network (or, in some cases, reduces the number of messages required to transmit this information if it cannot be included in a single message). This limits the energy consumption and radio resources required for the terminal to transmit messages.

[0015] This compression may also have the advantage of allowing more identifiers to be sent in a single message for a given message size. This can have the effect of improving the accuracy of geolocation.

[0016] Since the shortened identifier sent in the message cannot be decompressed in advance by a third party that intercepts the message, this compression also has advantages from the standpoint of data confidentiality.

[0017] However, this compression introduces ambiguity regarding the transmitter identifier because the shortened identifier may match multiple transmitter identifiers stored in the geolocation server's database.

[0018] This invention is based on the fact that an access network can resolve this ambiguity using an ambiguity resolution database that can clarify the identifier of a caller based on a shortened identifier. The ambiguity resolution database can create a list of caller identifiers, each list being associated with a different value of identification information. The access network clarifies the caller identifier based on the shortened identifier and the identification information clarified based on the message received from the terminal and the ambiguity resolution database. The identification information can be clarified directly based on parameters contained in the message sent by the terminal and / or based on information available within the access network, associated with the terminal that sent the message, and derived from this message. In the first step, the list associated with the value of the identification information clarified based on the message received from the terminal is clarified within the ambiguity resolution database. In the second step, the caller identifier corresponding to the shortened identifier is clarified within this list. The risk of ambiguity in the list associated with the value of the identification information clarified based on the message received from the terminal is significantly reduced (ambiguity exists if multiple identifiers corresponding to the same shortened identifier remain in the list). In fact, the size of the list created based on the ambiguity resolution database is usually much smaller than the size of the list of all caller identifiers stored in the geolocation server's database. The size of the list created based on the ambiguity resolution database varies depending on the selected identifier. In other words, by appropriately selecting the identifier, the access network can eliminate ambiguity regarding the identifier of the transmitting device in most cases.

[0019] Note that the "geographical location" of the transmitting device stored in the geographical location specific database may generally coincide with the location information representing the exact geographical location of the transmitting device. Therefore, this may directly be the coordinates (longitude, latitude, and optionally altitude) of the geographical location of the transmitting device, or may also be background information that can estimate the exact geographical location of the transmitting device (for example, postal code, store name, district name, region name, or country name, etc.).

[0020] In certain embodiments, the present invention may further include one or more of the following features, individually or in any technically possible combination.

[0021] In certain embodiments, the identification information includes information representing the terminal group to which the terminal belongs, and / or information representing the geographical area where the terminal is located, and / or information representing at least one other identifier or short identifier of the transmitting device detected by the terminal.

[0022] In certain embodiments, obtaining the short identifier of the transmitting device includes truncating at least a part of the identifier of the transmitting device.

[0023] In certain embodiments, obtaining the short identifier of the transmitting device includes estimating a value representing the ability to identify each part of the identifier for various parts of the identifier of the transmitting device, and selecting at least a part to be truncated according to the estimated value.

[0024] In certain embodiments, obtaining the short identifier of the transmitting device includes calculating a hash key using a hash function.

[0025] In certain embodiments, the hash function is implemented by a machine learning algorithm pre-trained to clarify an optimal hash key for the identifier of the transmitting device.

[0026] In certain embodiments, the first wireless communication protocol is a communication protocol of a wireless wide area network or a low power consumption wireless wide area network.

[0027] In a particular embodiment, the second wireless communication protocol is a communication protocol of a wireless local area network, a communication protocol of a wireless personal area network, or a communication protocol of a short-range communication system.

[0028] According to a second aspect, the present invention relates to a method for updating an ambiguity resolution database as described in any one of the above-described embodiments. This updating method includes, inter alia, - a step of detecting an identifier of a transmitting device at a terminal of a wireless communication system based on a message transmitted by the transmitting device, - a step of evaluating at the terminal a criterion for determining whether to transmit, in the message, either the identifier of the transmitting device or a shortened identifier of the transmitting device towards an access network, - a step of updating the ambiguity resolution database when the message transmitted by the terminal contains the identifier of the transmitting device in its full form including.

[0029] In a particular embodiment, the criterion is evaluated according to the number of identifiers of the transmitting device detected by the terminal over a predetermined period of time and / or according to an indication given by a sensor of the terminal and / or according to a determination by the terminal if the identifier of the transmitting device has already been transmitted and / or according to a configuration defined by the access network and transmitted by the access network to the terminal in a configuration message.

[0030] According to a third aspect, the present invention relates to a server connected to an access network of a wireless communication system (which may be a server directly belonging to the access network or a third-party server connected to the access network). The system has at least one terminal adapted to exchange messages with the access network according to a first wireless communication protocol and, for at least one transmitter, adapted to detect the identifier of the transmitter according to a second wireless communication protocol based on a message transmitted by the transmitter. The server is configured to receive a message from the terminal containing a shortened identifier of the transmitter. The shortened identifier is the result of irreversible compression of the transmitter identifier. The server is also configured to decipher the transmitter identifier based on the shortened identifier, the identification information deciphered based on the message transmitted by the terminal, and an ambiguity resolution database. The ambiguity resolution database can create multiple lists of transmitter identifiers, each list being associated with a different value of the identification information. The ambiguity resolution database is stored on this server or one or more other servers. The server is further configured to estimate the geolocation of the terminal based on the transmitter identifier and using a geolocation database. The geolocation database stores a list of transmitter identifiers and the geographic location of each transmitter. The geolocation database is stored by a different geolocation server than the server that stores the ambiguity resolution database.

[0031] The server may be configured to implement any one of the embodiments of the geolocation method described above.

[0032] In certain embodiments, the server is further configured to receive a message from the terminal containing the identifier of the sending device and to update the ambiguity resolution database based on the received identifier.

[0033] According to a fourth aspect, the present invention relates to an access network including a server according to any one of the embodiments described above.

[0034] In certain embodiments, the access network is a wireless wide-area network or a low-power wireless wide-area network.

[0035] According to a fifth aspect, the present invention relates to a terminal for a wireless communication system. The terminal is adapted to exchange messages with an access network in accordance with a first wireless communication protocol. The terminal is configured to detect the identifier of a transmitting device based on a message transmitted by a transmitting device, in accordance with a second wireless communication protocol. The terminal is further configured to evaluate a criterion that determines whether the terminal should transmit the identifier of the transmitting device or the abbreviated identifier of the transmitting device to the access network in the message. If the abbreviated identifier must be transmitted, the terminal is configured to irreversibly compress the identifier of the transmitting device in order to obtain the abbreviated identifier of the transmitting device. Finally, the terminal is configured to transmit a message containing either the identifier of the transmitting device or the abbreviated identifier of the transmitting device to the access network, in accordance with the evaluation result of the criterion.

[0036] In certain embodiments, the criteria are evaluated according to the number of transmitter identifiers detected by the terminal over a predetermined period, and / or according to instructions issued by the terminal's sensors, and / or according to a determination by the terminal if the transmitter identifier has already been transmitted, and / or according to a configuration defined by the access network and transmitted by the access network to the terminal in a configuration message.

[0037] The present invention will be better understood by reading the following description, which is given as a non-limiting example with reference to Figures 1 to 4. [Brief explanation of the drawing]

[0038] [Figure 1] This is a schematic diagram of an example of a wireless communication system used to determine the geographic location of a terminal using a geolocation server. [Figure 2] This is a schematic diagram of an embodiment of the terminal. [Figure 3]This is a schematic diagram outlining the main stages of the method for determining the geographic location of a device. [Figure 4] This is a diagram illustrating an example of a method for determining the geographic location of a device. [Figure 5] This is a diagram illustrating an example of a possible structure for an ambiguity resolution database. [Figure 6] This is a schematic diagram outlining the main stages of the method for updating the ambiguity resolution database. [Modes for carrying out the invention]

[0039] In these diagrams, if the same symbol appears in one diagram and another, it refers to the same or similar element. For clarity, the elements shown are not necessarily at the same scale unless otherwise specified.

[0040] Figure 1 is a schematic diagram of a wireless communication system 10 that includes at least one terminal 20 and an access network 30 having multiple base stations 31.

[0041] Terminal 20 is configured to send messages on the uplink to the access network 30. Each base station 31 is configured to receive messages from terminal 20 when the terminal is within range of that base station. Conventionally, messages sent by terminal 20 include the identifier of terminal 20. Each message received by a base station is sent, for example, to a server 32 on the access network 30, and may be accompanied by other information such as the identifier of the base station 31 that received it, the received power level of the message, the time the message arrived, and the frequency with which the message was received. The server 32 processes all messages received, for example, from different base stations 31.

[0042] The wireless communication system 10 may be unidirectional; that is, messages can only be exchanged on the uplink from the terminal 20 to the access network 30. However, this does not preclude bidirectional exchange, as is possible in other examples. If necessary, the access network 30 may also be configured to send messages downlink via the base station 31 to terminals 20 that are capable of receiving them.

[0043] The first wireless communication protocol is used for message exchange over the uplink toward access network 30.

[0044] In certain embodiments, the first wireless communication protocol is a communication protocol for a wireless wide area network (WWAN). For example, the first wireless communication protocol is a standardized communication protocol such as UMTS (Universal Mobile Telecommunications System), LTE (Long Term Evolution), LTE-Advanced Pro, or 5G.

[0045] Alternatively, the first wireless communication protocol is a Low Power Wide Area Network (LPWAN) communication protocol. Such wireless communication systems are long-range access networks (over 1 kilometer, or even tens of kilometers), have minimal energy consumption (e.g., less than 100mW, 50mW, or even 25mW when sending or receiving a message), and generally have speeds of less than 1 Mbits / s. Examples of LPWAN networks include Sigfox, LoRaWAN, Ingenu, Amazon Sidewalk, and Helium. Such wireless communication systems are particularly well-suited for IoT or M2M type applications.

[0046] In IoT or M2M type communication systems, data exchange is inherently unidirectional, in this case over the uplink from the terminal 20 of the wireless communication system 10 to the access network 30. To minimize the risk of message loss transmitted by the terminal 20, the access network is often planned so that a particular geographic area is covered simultaneously by multiple base stations 31, allowing multiple base stations 31 to receive messages transmitted by the transmitting device 20.

[0047] In the following explanation, as a non-restrictive example, we consider the first wireless communication protocol to be a low-power, ultra-narrowband wireless wide-area network communication protocol. "Ultra-narrowband" (UNB) refers to a frequency bandwidth of less than 2 kilohertz, and even less than 1 kilohertz, of the instantaneous frequency spectrum of the radio signal transmitted by the terminal.

[0048] As shown in Figure 1, terminal 20 is also adapted to receive messages transmitted by at least one transmitting device 40 located in the vicinity of terminal 20. Messages transmitted from transmitting device 40 use a second wireless communication protocol different from the first wireless communication protocol. Note that transmitting device 40 may be completely independent of the wireless communication system 10 and does not need to support the first wireless communication protocol.

[0049] In certain embodiments, the range of the second wireless communication protocol is narrower than the range of the first wireless communication protocol. In such cases, the geographic location of the transmitting device 40 within a range of the terminal 20 provides more accurate information about the geographic location of the terminal 20 than, for example, the geographic location of the base station 31 that receives messages transmitted by the terminal 20.

[0050] However, it should be noted that, as other examples suggest, it is possible to have a second wireless communication protocol with a range exceeding that of the first wireless communication protocol.

[0051] The second wireless communication protocol could be, for example, a Wireless Local Area Network (WLAN), such as a WiFi type (IEEE 802.11 standard), or a Wireless Personal Area Network (WPAN), such as a Bluetooth or BLE (Bluetooth Low Energy) type. Another example would be a short-range communication protocol based on NFC (Near Field Communication) technology or RFID (Radio Frequency Identification) technology.

[0052] The geolocation server 50 includes a database called the "geographic location database," which contains a table that stores identifiers for the transmitters 40. If the identifier for the transmitter 40 is in the geolocation database, that identifier is associated in the table with at least one location piece representing the geographic location of the transmitter 40.

[0053] The identifier for the transmitter 40 corresponds, for example, to the MAC address of the transmitter 40 (MAC stands for "Media Access Control" in English, and "controle d'acces au support" in French, meaning "media access control"). However, other parameters can also serve as identifiers for the transmitter 40, such as the SSID (abbreviation for "Service Set IDentifier" in English, and "identificateur d'ensemble de services" in French) or BSSID (abbreviation for "Base Service Set IDentifier" in English, and "identificateur d'ensemble de services debase" in French) of a WiFi access point, an identifier for a Bluetooth or BLE access point, or an identifier for an RFID tag.

[0054] The location information may be the coordinates (longitude, latitude, and possibly altitude) of the geographic location of the transmitting device 40. However, the location information may also be background information that allows the geographic location of the transmitting device 40 to be estimated, such as a postal code, store name, district name, region name, or country name.

[0055] The geolocation server 50 is connected to the server 32 of the access network 30, for example, via an internet connection.

[0056] Figure 2 is a schematic diagram of an embodiment of terminal 20.

[0057] As shown in Figure 2, terminal 20 has a first communication module 21 adapted to exchange messages with base station 31 according to a first wireless communication protocol. The first communication module 21 is in the form of a wireless circuit that includes, for example, equipment (antenna, amplifier, local oscillator, mixer, analog filter, etc.).

[0058] Terminal 20 also has a second communication module 22 which is adapted to receive messages transmitted from the target transmitter 40 in accordance with a second wireless communication protocol. The second communication module 22 is in the form of a wireless circuit that includes, for example, equipment (antenna, amplifier, local oscillator, mixer, analog filter, etc.).

[0059] Furthermore, the terminal 20 also has a processing circuit 23 connected to the first communication module 21 and the second communication module 22. The processing circuit 23 includes, for example, one or more processors and storage means (such as a magnetic hard disk, electronic memory, or optical disk), and the storage means stores a computer program product in the form of a set of program code instructions that performs at least a certain number of steps of a method for determining the geolocation of the terminal and a method for updating the ambiguity resolution database (see below).

[0060] The server 32 of the access network 30 also includes one or more processors and storage means, the storage means storing a computer program product in the form of a set of program code instructions to be executed to carry out at least a certain number of steps of a method for geolocating terminals and a method for updating an ambiguity resolution database (see below).

[0061] Figure 3 is a schematic diagram of the main steps of an embodiment of the method 100 according to the present invention for determining the geographic location of terminal 20.

[0062] The geolocation method 100 includes a step 101 in which, for at least one transmitting device 40, the terminal 20 detects the identifier of the transmitting device 40 based on a message transmitted by the transmitting device 40 in accordance with a second wireless communication protocol.

[0063] The geolocation method 100 then includes a step 102 in which the terminal 20 obtains a shortened identifier of the transmitter 40. The shortened identifier is the result of lossy compression of the identifier of the transmitter 40. Therefore, the shortened identifier corresponds to information representing the identifier of the transmitter 40 that is smaller in size than the identifier of the transmitter 40. For example, the identifier of the transmitter 40 is encoded with 64 bits, but the shortened identifier is encoded with only 12 bits. However, this information can be so ambiguous that multiple different identifiers of the transmitter may share the same shortened identifier.

[0064] The geolocation method 100 then includes step 103 of sending a message containing the abbreviated identifier of the transmitting device 40 to the access network 30 from the terminal 20. This message is sent in accordance with a first wireless communication protocol.

[0065] The geolocation method 100 then includes a step 104 in which the identifier of the transmitting device 40 is clarified by the access network 30 based on the abbreviated identifier and using a database called the "ambiguity resolution database". The ambiguity resolution database makes it possible to create various lists of transmitting device identifiers, each list being associated with a different value of the identification information. Based on the message transmitted by the terminal 20, a specific value of the identification information can be clarified. A list associated with the clarified value of the identification information based on the message received from the terminal 20 can be created using the ambiguity resolution database. The next step is to clarify the transmitting device identifier corresponding to the abbreviated identifier from this list. The risk of ambiguity in the list associated with the clarified value of the identification information based on the message received from the terminal is greatly reduced. In fact, the size of the list created based on the ambiguity resolution database is smaller than the size of the list of all transmitting device identifiers stored in the geolocation server's database.

[0066] The geolocation method 100 then includes a step 105 in which the geolocation of the terminal 20 is estimated based on the identifier of the transmitting device and using the geolocation database of the geolocation server 50.

[0067] The estimated geographic location of terminal 20 corresponds, for example, to the location of the transmitter 40 stored in a geolocation database. The geographic location of terminal 20 may be refined depending on the power level at which terminal 20 receives beacon signals, or using known metadata of the access network 30. It is also possible to estimate the geographic location of terminal 20 based on the geographic locations of multiple different transmitters 40 detected by terminal 20 at a specific time.

[0068] In the example considered, the step 104 of clarifying the identifier of the transmitting device 40 based on the abbreviated identifier and the ambiguity resolution database is performed by the server 32 of the access network 30.

[0069] Step 105, which estimates the geolocation of terminal 20 based on the identifier of the transmitter 40 and the geolocation database, is performed by the server 32 and / or geolocation server 50 of the access network 30. In the first example, the server 32 of the access network 30 transmits the identifier of the transmitter 40 to the geolocation server 50, or transmits all available identifiers when multiple transmitters are detected by the terminal, and the geolocation server 50 estimates the location of terminal 20 based on the geolocations associated with the various identifiers in the geolocation database. In the second example, the geolocation server 50 simply returns the geolocations associated with each identifier in the geolocation database, and it is the server 32 that estimates the location of terminal 20 based on the geolocations associated with the various identifiers.

[0070] The ambiguity resolution database is stored, for example, on server 32 and / or multiple other servers in the access network 30, or on servers not belonging to the access network 30. However, this is an example where the servers storing the ambiguity resolution database are different from the geolocation server 50. These servers contain information that the geolocation server 50 is unaware of, and this information can resolve ambiguities that may arise when clarifying the identifier of the transmitter 40 based on the abbreviated identifier. This allows the operator of the ambiguity resolution database to maintain the database without relying on the operator of the geolocation database. Furthermore, the identification information can be associated with private information that is known only to the access network and should not be communicated to the geolocation server 50.

[0071] Figure 4 shows an embodiment of the geolocation method 100 according to the present invention. In this example, nine transmitters 40 are considered, each associated with identifiers ID1, ID2, ..., ID9. Correspondence table 21 shows the abbreviated identifiers associated with each identifier ID1, ID2, ..., ID9. In this example, there are six abbreviated identifier values: CID1, CID2, ..., CID6. It can be seen that abbreviated identifier CID1 is associated with identifiers ID1 and ID3 simultaneously, abbreviated identifier CID2 is associated with identifiers ID2 and ID6 simultaneously, abbreviated identifier CID3 is associated with identifier ID4, abbreviated identifier CID4 is associated with identifiers ID5 and ID7 simultaneously, abbreviated identifier CID5 is associated with identifier ID7, and abbreviated identifier CID6 is associated with identifier ID9. Therefore, because the same abbreviated identifier is associated with multiple different identifiers, there is ambiguity, and as a result, it is impossible to reliably clarify the identifier of a transmitter based on the abbreviated identifier.

[0072] In the example shown in Figure 4, terminal 20 detects the transmitting device 40 whose identifier is ID3.

[0073] Therefore, terminal 20 compresses identifier ID3 to obtain the abbreviated identifier CID1 associated with identifier ID1 (for this to work, it is assumed that terminal 20 recognizes a compression function that can obtain an abbreviated identifier based on the identifier of the transmitting device, or that terminal 20 is aware of the correspondence table 21).

[0074] Terminal 20 then sends a message containing the abbreviated identifier CID1 to the access network 30. The access network 30, or more specifically, server 32, then attempts to clarify the identifier of the sending device 40 based on the abbreviated identifier CID1 and using the ambiguity resolution database 33.

[0075] In this example, the ambiguity resolution database 33 can create various lists of caller identifiers, each associated with a different value of the identification information: info1, info2, ..., info5. As a non-restrictive example, the identification information corresponds to the name of a customer company in the access network 30 to which terminal 20 belongs. In other words, in this example, the ambiguity resolution database 33 can create a list of caller identifiers for each of the multiple customer companies (info1, info2, ..., info5) in the access network 30 that have already been detected by terminals belonging to that customer company. The caller identifiers for caller 40 already detected by terminals belonging to the customer company named info1 are ID1, ID4, and ID5, the caller identifiers for caller 40 transmitted from terminals belonging to the customer company named info2 are ID2 and ID9, and so on.

[0076] In this example, server 32 can determine that the identifier value for the message received from terminal 20 is info3. In other words, server 32 can determine that the customer company to which terminal 20, which just sent a message containing the abbreviated identifier CID1, belongs is customer company info3. This information is either explicitly included in the message received from terminal 20, or it can be extracted from the message received from terminal 20 (for example, the message also includes the identifier of terminal 20, and server 32 can determine which customer company terminal 20 belongs based on the identifier of terminal 20).

[0077] Therefore, the remaining task is to determine which of the identifiers ID3, ID7, and ID8 of the calling device 40 in the list associated with the identification information having the value info3 corresponds to the abbreviated identifier CID1. In this list, only identifier ID3 has the abbreviated identifier CID1. Therefore, the server 32 clarifies that the identifier of the calling device 40 detected by terminal 20 is most likely to be ID3.

[0078] Naturally, this assumes that server 32 recognizes a compression function that allows it to obtain the identifier of the transmitting device based on the shortened identifier, or that access network 32 recognizes the correspondence table 21.

[0079] Next, the access network can send a message containing identifier ID3 to the geolocation server 50. The geolocation server 50 includes a geolocation database 51 that stores identifiers of the transmitting device 40, and each of these identifiers is associated with at least one location information representing the geolocation of the transmitting device 40. In this example, identifier ID1 is associated with location information pos1, identifier ID2 is associated with location information pos2, and so on, with identifier ID9 being associated with location information pos9. Therefore, the geolocation of terminal 20 can be estimated to be the geolocation of the transmitting device 40 whose identifier is ID3, i.e., the geolocation associated with pos3.

[0080] In the example shown in Figure 4, only the identifier of the transmitting device 40 is being considered for detection by the terminal 20. However, the present invention can also be applied when multiple identifiers corresponding to various transmitting devices 40 are detected by the terminal 20 over a certain period of time, and then transmitted to the access network 30 in a single message or multiple messages. Thus, the geographic location of the terminal 20 can be clearly determined according to the various location information associated with the various transmitting devices detected in the geolocation database 51.

[0081] In the example shown in Figure 4, without the ambiguity resolution database 33, it would have been impossible for the access network 30 and the geolocation server 50 to reliably determine which of the identifiers ID1 and ID3 (i.e., identifiers with the abbreviated identifier CID1) corresponds to the transmitter 40 detected by terminal 20. Therefore, it would have been impossible to estimate the geolocation of terminal 20 (because the terminal's geolocation could correspond to either pos1 or pos3).

[0082] Therefore, the present invention makes it possible to reduce the amount of information transmitted by the terminal 20 (by compressing the identifier) ​​while limiting the risk of ambiguity when clarifying the identifier of the transmitting device 40 (by having an ambiguity resolution database 33).

[0083] It should be noted that ambiguity resolution is not always guaranteed, especially when multiple identifiers with the same abbreviated identifier respond to the same identifier value. However, the risk of ambiguity remaining can generally be significantly reduced by appropriately selecting the identifier.

[0084] The identification information can be considered to be information representing the terminal group to which terminal 20 belongs (for example, the name of the customer company to which terminal 20 belongs, the model corresponding to terminal 20, etc.).

[0085] The identification information may also correspond to the geographical region where terminal 20 is located. In this case, the access network 30 must be able to clearly identify the geographical location of terminal 20 without using a geolocation server 50.

[0086] The location information of terminal 20 may correspond to the estimated coordinates (longitude, latitude, and possibly altitude) of the terminal 20's geographical location, and may indicate the accuracy of this estimated location. However, the location information of terminal 20 may also be background information that allows for the estimation of the terminal 20's approximate geographical location, such as a postal code, store name, district name, region name, or country name. This background information can be obtained, in particular, from parameters associated with messages received from terminal 20. For example, if the access network recognizes that this terminal belongs to a customer company that operates only in a specific region or country, it is possible to determine whether terminal 20 is located in that region or in which country based on the terminal's identifier.

[0087] The access network 30 is configured, for example, to estimate the geographic location of terminal 20 in response to a message received from terminal 20. In a particular embodiment, the geographic location is estimated from a message received that includes the identifier of the transmitting device 40. However, this does not preclude estimating the geographic location of terminal 20 based on other messages previously transmitted from terminal 20, according to other examples.

[0088] Various methods can be used to estimate the geographic location of terminal 20. For example, the access network 30 can estimate the geographic location of terminal 20 as the geographic location of the base station 31 that received the message transmitted by terminal 20. If multiple base stations 31 can receive the message transmitted by terminal 20, it is possible to estimate the geographic location of terminal 20 based on the geographic locations of all the base stations 31 that received the message transmitted by terminal 20 (for example, by defining the centroid of these geographic locations).

[0089] In another example, the access network 30 can calculate the time it takes for a message transmitted by terminal 20 to propagate to base stations 31 from TOA measurements or Time Difference of Arrival (TDOA) measurements at various base stations 31, and estimate the distance separating terminal 20 from one or more base stations 31. Therefore, if the geographic location of base station 31 is known, it is possible to estimate the location of terminal 20 using multilateration.

[0090] In another example, for a message sent by terminal 20 to the access network 30, it is possible to calculate the distance separating terminal 20 from multiple base stations 31 and estimate the location of terminal 20 using multilatency based on the RSSI measurement values ​​of each base station 31.

[0091] In yet another example, the method for estimating the geographic location of terminal 20 by access network 30 can utilize machine learning techniques that associate wireless fingerprints with geographic locations in a target geographic area.

[0092] In certain embodiments, the geolocation of terminal 20 is estimated by the access network 30, and no explicit information related to this estimation is transmitted from the terminal in a message directed to the access network (in other words, the terminal does not send a message to the access network that contains information in binary data that could allow the terminal's geolocation to be estimated). Such a provision makes it possible to limit the amount of data exchanged between the terminal and the access network in order to determine the geolocation of terminal 20.

[0093] The identification information may correspond to information representing at least one other identifier (or at least one other abbreviated identifier) ​​of the transmitter 40 detected by terminal 20. In fact, transmitters 40 that are geographically close to each other are generally detected by terminal 20 at the same time. This information makes it possible to resolve ambiguity regarding the identifier of the transmitter. For example, even if two transmitters respond to the same abbreviated identifier, if only one of these two transmitters has already been detected at the same time as another transmitter indicated in a message sent by terminal 20, then it is highly likely that this transmitter is the one detected by terminal 20.

[0094] Based on information explicitly included in the message received from terminal 20, or based on the metadata of the message recognized by the access network 30, many other examples of identifying information can be considered and clarified. This selection of specific identifying information is merely one variation of the present invention.

[0095] Identification information may be considered to correspond to a combination of multiple pieces of information with different properties.

[0096] Various structures can be considered for storing data in the ambiguity resolution database 33. The selection of this particular structure for the ambiguity resolution database 33 is merely one variation of the present invention.

[0097] Figure 4 shows a first example in which the ambiguity resolution database 33 stores various lists of identifiers, each associated with a different value of the identification information.

[0098] Figure 5 shows an alternative, non-restrictive example of a possible structure for the ambiguity resolution database 33.

[0099] In the example shown in Figure 5, each row corresponds to a message received from terminal 20 of the communication system 10. For each received message, multiple pieces of information about that message are stored. For example, information C1, C2, ..., CK correspond to features about terminal 20 that the access network 30 has clarified based on the message. In particular, this may be explicit data contained in the message, or metadata associated with the message or the terminal that sent the message (e.g., terminal identifier, name of customer company to which the terminal belongs, specific type of terminal, specific service associated with the terminal, information about the geographic location of the terminal clarified by the access network, etc.). For each received message, the ambiguity resolution database 33 also stores the abbreviated identifier CID of the sender indicated in the message, and if clarified, also stores the sender identifier ID. If multiple senders are detected by terminal 20 and recorded in a message sent to the access network 30, the abbreviated identifier can be stored for that message, and if clarified, the identifiers of these various senders can also be stored.

[0100] Therefore, one piece of identification information can be considered to correspond to a specific characteristic that has been clearly defined for the received message, or a combination of specific characteristics that have been clearly defined for the received message.

[0101] For example, if the access network 30 can determine that a terminal belongs to customer company A (C1=A) and is located in country B (C2=B), it is possible to request the ambiguity resolution database 33 to create a list of identifier IDs associated with messages previously received within the base that also satisfy conditions (C1=A) and (C2=B). The next step is to determine which identifiers in this list correspond to the abbreviated identifier shown in the message being processed.

[0102] In another example, a feature (e.g., C3) may correspond to the coordinates of the approximate geographic location of terminal 20 as clarified by the access network 30 (C3 = C). In this case, we can consider requesting the ambiguity resolution database 33 to create a list of identifier IDs associated with messages previously received within the base, where the location indicated for feature C3 belongs to a geographic region having a specific diameter centered at C.

[0103] Note that if the abbreviated identifier shown in the processing message is D, it is also possible to directly include the condition (CID=D) in the request made to the ambiguity resolution database 33. In this case, if there is no remaining ambiguity, the resulting list will contain only one element.

[0104] If ambiguity remains in the list obtained after making a request to the ambiguity resolution database 33 (i.e., if the list contains multiple identifiers that respond to the same abbreviated identifier), you can consider making another request with higher selectivity.

[0105] Therefore, various measures can be devised to clarify the identifier of the transmitter 40 in step 104 of the geolocation method 100. The first measure may consist of issuing a first request with sufficiently low selectivity to the ambiguity resolution database 33, and then issuing other requests with higher selectivity only if necessary and only if ambiguity remains in the list obtained from the responses to previous requests. The second measure may consist of issuing an extremely selectivity request immediately after the first request, so that there is no ambiguity after obtaining the response to the first request. This measure can be refined in some cases along with the received message in order to gradually reduce the complexity of the request, as long as there is no ambiguity remaining in the list obtained from the responses to the request. In some cases, a machine learning algorithm can be implemented to clarify the best request in terms of a compromise between the complexity of the request and the risk of ambiguity remaining in the list obtained from the responses to the request. This can be done, for example, using the decision tree forest (random forest) algorithm. This algorithm is known to be effective in distributing data across partitions even when the number of criteria reaches a large value. In this case, each leaf of the decision tree constitutes a list of identifiers, and the path to reach the leaf corresponds to the identification information. The identification information can change depending on the received message, according to rules that can be quite complex.

[0106] In reality, there is a trade-off to be found between the complexity (and selectivity) of the request, the risk of ambiguity remaining in the list obtained in response to the request, and the risk of not finding an identifier that corresponds to the abbreviated identifier in the list obtained in response to the request. In fact, the higher the selectivity of the request, the fewer elements there will be in the list obtained in response to the request, and the lower the risk of ambiguity remaining in these identifiers. On the other hand, the higher the selectivity of the request, the higher the risk of not finding an identifier that corresponds to the abbreviated identifier.

[0107] Regarding step 102, which involves obtaining a shortened identifier, it is also possible to consider various countermeasures through irreversible compression of the identifier of the transmitting device 40.

[0108] In certain embodiments, a shortened identifier can be created by truncating at least a portion of the identifier of the transmitter 40. The portion to be truncated may correspond to, for example, a specific portion of the high-order or low-order bits of the identifier.

[0109] In another example, the truncated portion can be selected by estimating the distinctiveness of each part of the identifier and choosing the truncated portion with the lowest distinctiveness. For example, the identifier may include a portion with several bytes of bits allocated to identifying the company that manufactured the transmitter 40. This portion gives rise to millions of possibilities, but in reality, the number of companies identified by this portion is only a few thousand. Therefore, it is advantageous to truncate this portion rather than others in order to create a partial identifier. In general, it is possible to utilize the difference between the theoretical space and the effective space of an identifier, and its bitwise representation. In the above case, the bits that identify the company have lower distinctiveness than the other bits. To clarify the optimal encoding of the abbreviated identifier from the perspective of distinctiveness, it can be considered to perform simulations depending on the truncated portion and experimentally measure the collision rate (a collision means that one or more identifiers correspond to one identical abbreviated identifier).

[0110] In certain embodiments, the abbreviated identifier of the transmitter 40 is clarified based on the calculation of a hash key using a hash function. Note that the hash function used and the size of the hash key may differ among different groups of terminals. However, the terminals must be aware of the hash function to use in order to decompress the abbreviated identifier depending on the terminal that performed the compression.

[0111] In certain embodiments, the hash function is implemented by a machine learning algorithm pre-trained to determine the optimal hash key for the transmitter identifier. For example, a deep neural network can be used to create the optimal hash key by incorporating the original identifier into a latent vector space. Such a method minimizes the collision rate. Thus, the determined hash function is more effective because it is adapted to the data.

[0112] Here, we need to focus on how we can create and keep up-to-date an ambiguity resolution database 33.

[0113] Figure 6 is a schematic diagram of the main steps in an example of implementing method 200 to update the ambiguity resolution database 33 (or create one if it does not exist).

[0114] The update method 200 includes a step 201 in which a terminal 20 of the wireless communication system 10 detects the identifier of at least one transmitter 40 based on a message transmitted by the transmitter 40. Note that this may be the same terminal 20 as described above in the description of the geolocation method 100, or a different terminal 20. Also note that this may be the same transmitter 40 as described above in the description of the geolocation method 100, or a different transmitter 40.

[0115] The update method 200 then includes a step 202 in which the terminal 20 evaluates a criterion to determine whether the terminal 20 should transmit either the identifier of the transmitting device 40 or the abbreviated identifier of the transmitting device 40 to the access network 30 within the message. Naturally, if the terminal 20 detects multiple identifiers, this step 202 of evaluating the criterion for the identifiers can be repeated for the multiple identifiers. Thus, the terminal can transmit a combination of the fully-form identifier and / or the abbreviated identifier to the access network 30 within the message.

[0116] Finally, method 200 includes step 203 of updating the ambiguity resolution database 33 by the access network 30 (more specifically by the server 32) if the message transmitted by terminal 20 contains an identifier of the transmitting device 40. This step may, in particular, consist of storing in the ambiguity resolution database 33 the association between the full-form identifier, the abbreviated-form identifier, and one or more pieces of identification information.

[0117] These measures allow the identifiers of the transmitters to be stored in the ambiguity resolution database 33 in their full (unshortened) form, and to be associated with the identification information clarified by the access network 30.

[0118] Several methods can be considered to evaluate the criteria that would allow terminal 20 to determine whether it should send a full identifier or a shortened identifier.

[0119] In certain embodiments, the criterion is evaluated based on the number of transmitter identifiers detected by terminal 20 over a specific predetermined period. In a non-limiting example, if terminal detects only one identifier, the complete identifier is transmitted. If two identifiers are detected, one of the two identifiers is transmitted in its complete form and the other in its abbreviated form. If three or more identifiers are detected, all identifiers are transmitted in their abbreviated form.

[0120] In certain embodiments, terminal 20 is configured to transmit a certain percentage of identifiers in full form. In a non-limiting example, terminal 20 is configured to transmit one in two identifiers in full form and one in two identifiers in abbreviated form.

[0121] In certain embodiments, terminal 20 is configured to gradually reduce the proportion of identifiers transmitted in complete form. In a non-limiting example, terminal 20 is configured to transmit all identifiers in complete form over a first period, then every other identifier over a second period, then every four identifiers over a third period, and so on.

[0122] In certain embodiments, terminal 20 is configured to evaluate criteria in response to instructions from its sensors. These criteria may include, for example, instructions regarding the start or end of a movement phase of terminal 20 (it is advantageous to transmit the identifier in full form when terminal 20 is moving in a way that facilitates geolocation), or instructions regarding a specific temperature or pressure experienced by terminal 20 (if such a warning instruction is detected, it is advantageous to transmit the identifier in full form, even if it is inconvenient to have to transmit the identifier in full form, in order to facilitate geolocation of terminal 20). The sensors may include motion sensors (accelerometers, gyroscopes, magnetometers, etc.), temperature sensors, pressure sensors, smoke sensors, noise sensors, and the like.

[0123] In certain embodiments, terminal 20 is configured to evaluate whether the identifier of the transmitter 40 has already been transmitted by terminal 20 (if the identifier has been transmitted in full form, it may only be transmitted in abbreviated form thereafter). It should also be noted that the concept of time can be introduced. The criterion may, in particular, consider the date on which the identifier of the transmitter 40 was previously transmitted. If the date is far in the past, it is advantageous to successfully transmit the identifier in full form. If the date is recent, it is advantageous to transmit the identifier in abbreviated form.

[0124] In a particular embodiment, terminal 20 is configured to evaluate criteria according to the configuration defined by the access network 30 and using a configuration message transmitted by the access network 30 to terminal 20. In this case, the communication system must be bidirectional. Various configurations can be considered depending on the time and / or the geographic location of terminal 20.

[0125] Naturally, the criteria can also be evaluated in relation to combinations of the examples given above. Furthermore, other methods can be considered for evaluating criteria that would allow for clarification of whether the terminal 20 must transmit a full identifier or a shortened identifier. The selection of a specific method is merely one variation of the present invention.

[0126] Any type of interface can be considered between server 32 of the access network 30 and the geolocation server 50, and between server 32 and the server managing the ambiguity resolution database (if the ambiguity resolution database is managed on a different server than server 32). In particular, it is possible to consider using files, programming interfaces, callback functions, etc.

[0127] The above description clearly demonstrates that the various features and advantages of the present invention achieve the objectives set forth by the invention. In particular, the present invention makes it possible to limit the energy consumption and / or required wireless resources of a terminal while maintaining good geolocation performance.

Claims

1. A method (100) for determining the geographic location of a terminal (20) of a wireless communication system (10), The terminal (20) is adapted to exchange messages with the access network (30) of the wireless communication system (10) in accordance with a first wireless communication protocol. - A step (101) in which the terminal (20) detects the identifier of at least one transmitting device (40) based on a message transmitted by the transmitting device (40) in accordance with a second wireless communication protocol, - A step (102) in which the shortened identifier of the transmitting device (40) is obtained by the terminal (20) by irreversibly compressing the identifier of the transmitting device (40), wherein the shortened identifier may correspond to multiple different identifiers of the transmitting device (40), and therefore the irreversible compression introduces ambiguity. - Step (103) of transmitting a message including the abbreviated identifier of the transmitting device (40) to the access network (30) from the terminal (20), - A step (104) in which the identifier of the transmitting device (40) is clarified by the access network (30) based on the abbreviated identifier, the identification information clarified based on the message transmitted by the terminal (20), and the ambiguity resolution database (33) which can create multiple lists of the identifier of the transmitting device, and each list is associated with a different value of the identification information. - A step (105) in which the access network (30) estimates the geographic location of the terminal (20) based on the identifier of the transmitting device, and using a geolocation database (51) that stores a list of identifiers of transmitting devices and the geographic locations of each of the transmitting devices (40). Includes, The geolocation database (51) is stored in a geolocation server (50) managed by a first operator, and the ambiguity resolution database (33) is stored in one or more servers (32) different from the geolocation server (50), and the one or more servers (32) are managed by a second operator different from the first operator. Method (100).

2. The aforementioned identification information is - Information representing the terminal group to which the terminal (20) belongs, and / or - Information representing a geographic region where the terminal (20) is located, and / or - Information representing at least one other identifier or abbreviated identifier of the transmitting device (40) detected by the terminal (20) The method according to claim 1 (100), including the method according to claim 1.

3. The method according to claim 1 (100), wherein the acquisition (102) of the abbreviated identifier of the transmitting device (40) includes truncating at least a portion of the identifier of the transmitting device (40).

4. The acquisition of the abbreviated identifier (102) by the transmitting device (40) is as follows: - Estimate a value representing the ability to identify each part of the identifier of the transmitter (40) - Select at least a portion to be discarded according to the estimated value. The method according to claim 3 (100), including the method according to claim 3.

5. The method according to claim 1 (100), wherein the acquisition (102) of the abbreviated identifier of the transmitting device (40) includes calculating a hash key using a hash function.

6. The method according to claim 5 (100), wherein the hash function is implemented by a machine learning algorithm that has been pre-trained to determine the optimal hash key for the identifier of the transmitter.

7. The method according to claim 1 (100), wherein the first wireless communication protocol is a communication protocol for a wireless wide-area network or a low-power wireless wide-area network.

8. The method according to claim 1 (100), wherein the second wireless communication protocol is a communication protocol for a wireless local network, a communication protocol for a wireless personal network, or a communication protocol for a short-range communication system.

9. A method (200) for updating an ambiguity resolution database (33), - A step (201) in which the identifier of the transmitting device (40) is detected by the terminal (20) of the wireless communication system (10) based on the message transmitted by the transmitting device (40), - A step (202) in which the terminal (20) evaluates a criterion to clarify whether the identifier of the transmitting device (40) or the abbreviated identifier of the transmitting device (40) should be transmitted to the access network (30) by the terminal (20) in the message. - Step (203) to update the ambiguity resolution database (33) if the message transmitted by the terminal (20) contains the identifier of the transmitting device (40) in its complete form. The method according to any one of claims 1 to 8 (200), including the method according to any one of claims 1 to 8.

10. The aforementioned standards are, - In accordance with the number of transmitter identifiers detected by the terminal (20) over a predetermined period, and / or - In response to the instructions issued by the sensor of the terminal (20), and / or - If the identifier of the transmitting device (40) has already been transmitted, then, according to the determination of the terminal (20), and / or - In accordance with the configuration defined by the access network (30) and transmitted by the access network (30) to the terminal (20) in a configuration message The method according to claim 9 (200) is evaluated.

11. A server (32) connected to an access network (30) of a wireless communication system (10), wherein the wireless communication system (10) is adapted to exchange messages with the access network (30) in accordance with a first wireless communication protocol, and the server has at least one terminal (20) adapted to detect the identifier of at least one transmitter (40) in accordance with a second wireless communication protocol based on a message transmitted by the transmitter (40), wherein the server (32) - A message containing a shortened identifier of the transmitting device (40) is received from the terminal (20), and the shortened identifier is the result of irreversible compression of the identifier of the transmitting device (40), and since the shortened identifier may correspond to multiple different identifiers of the transmitting device (40), the irreversible compression introduces ambiguity. - An ambiguity resolution database (33) capable of creating multiple lists of the shortened identifier, the identification information clarified based on the message transmitted by the terminal (20), and the identifier of the transmitting device, wherein each list is associated with a different value of the identification information, and the identifier of the transmitting device (40) is clarified based on this ambiguity resolution database (33), which is stored on the server (32) or one or more other servers. - The geographic location of the terminal (20) is estimated based on the identifier of the transmitting device, and using a geolocation database (51) that stores a list of identifiers of the transmitting devices and the geographic locations of each transmitting device (40). The geolocation database (51) is stored in a geolocation server (50) that is different from the server (32) that stores the ambiguity resolution database (33), and the first operator who manages the geolocation server (50) is different from the second operator who manages the server (32) that stores the ambiguity resolution database (33). A server (32) characterized by being configured in such a way.

12. The server (32) further: - The device (40) receives a message from the terminal (20) that includes the identifier of the transmitting device (40). - Update the ambiguity resolution database (33) based on the received identifier. The server (32) according to claim 11, configured as follows.

13. An access network (30) including the server (32) according to claim 11 or 12.

14. The access network (30) according to claim 13, wherein the access network (30) is a wireless wide-area network or a low-power wireless wide-area network.

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