HYBRID LOCALIZATION IN A FIRST AREA AND IN A SECOND AREA AND DEVICE THEREFORE

Abstract

In one embodiment a method for hybrid localization in a first area and in a second area comprises the following steps: operating (A) a device in a first mode of operation, while the device is in the first area in which a wireless communication is available, detecting (B) that the device transitions from the first area to the second area in which a short range radio signal transmission is available, switching (C) the device to a second mode of operation upon detection that the device transitions from the first area to the second area, wherein in the first mode of operation the device uses a first technology for localization, wherein in the second mode of operation the device uses at least a second technology for localization in which the device emulates the short range radio signal transmission during at least one idle period of the wireless communication.

Claims

1. A method for hybrid localization in a first area and in a second area, the method comprising: operating a device in a first mode of operation, while the device is in the first area in which a wireless communication is available, detecting that the device transitions from the first area to the second area in which a short range radio signal transmission is available, and switching the device to a second mode of operation upon detection that the device transitions from the first area to the second area, wherein in the first mode of operation the device uses a first technology for localization, and wherein in the second mode of operation the device uses at least a second technology for localization in which the device emulates the short range radio signal transmission during at least one idle period of the wireless communication.

2. A method according to claim 1, wherein in the second mode of operation the device emulates a Bluetooth Low Energy positioning or an ultra-wide band positioning or a Wireless Local Area Network according to IEEE 802.11x, positioning during the at least one idle period of the wireless communication.

3. A method according to claim 2, wherein in the second mode of operation the device emulates the Bluetooth Low Energy positioning during the at least one idle period of the wireless communication by sending at least one Bluetooth direction finding packet during the at least one idle period of the wireless communication.

4. A method according to claim 1, wherein the at least one idle period of the wireless communication is a timespan during which no transmission on the wireless communication occurs.

5. A method according to claim 4, wherein the at least one idle period of the wireless communication conforms to a discontinuous reception (DRX) or an enhanced/extended DRX, connected mode DRX, or a power save mode, or a wake-up signal period, or a wake-up signal duration.

6. A method according to claim 1, wherein the device employs a wireless modem implementing bidirectional wireless communication according to a standard for the wireless communication, and wherein in the second mode of operation the device employs said wireless modem for sending at least one Bluetooth direction finding packet during the at least one idle period, the at least one Bluetooth direction finding packet comprising a constant tone extension and a packet data unit.

7. A method according to claim 1, wherein a duration of the at least one idle period is adjusted by way of negotiation.

8. A method according to claim 1, further comprising: detecting that the device transitions from the second area to the first area, and subsequently switching from the second mode of operation to the first mode of operation.

9. A method according to claim 1, wherein detecting the device transitions between the first area and the second area comprises an evaluation of a Cell Identification, or using a geo-fence service, or using a radio frequency fingerprinting or using a Global Navigation Satellite System service.

10. A method according to claim 1, wherein the first technology for localization comprises at least one of the following: a Global Navigation Satellite Service, a cellular telecommunication technology, a wireless communication technology.

11. (canceled)

12. A device for hybrid localization, the device comprising: a wireless modem configured to provide a bidirectional wireless communication capability according to a wireless communication standard, in a first mode of operation, and a processing unit configured to provide at least one packet having localization enabling information to the wireless modem in a second mode of operation, the packet conforming to a short range radio signal transmission, wherein the device is configured to be operated in the first mode of operation while the device is in a first area in which a wireless communication is available, the device further configured to be operated in the second mode of operation while the device is in a second area in which a short range radio signal transmission is available, wherein in the first mode of operation the device is configured to use a first technology for localization, and wherein in the second mode of operation the device is configured to use at least a second technology for localization, wherein the second technology comprises emulating the short range radio signal transmission during at least one idle period of the wireless communication.

13. A device according to claim 12, wherein the packet comprises a Bluetooth direction finding packet according to a Bluetooth Low Energy standard, and wherein the wireless modem is configured to provide a baseband transmission capability for the Bluetooth direction finding packet, to provide an up conversion for the direction finding packet to at least one Bluetooth advertising frequency channel, and to provide an output power to the up converted Bluetooth direction finding packet according to the Bluetooth Low Energy standard.

14. A device according to claim 12, wherein the device is implemented in a single chip.

15. A device according to claim 12, wherein the device is free from a dedicated short range radio signal transmission modem.

Description

[0046] The text below explains the proposed method and device in detail using exemplary embodiments with reference to the drawings. Components and circuit elements that are functionally identical or have an identical effect bear identical reference numbers. Insofar as circuit parts or components correspond to one another in their function, a description of them will not be repeated in each of the following figures. Therein,

[0047] FIG. 1 shows an exemplary embodiment of a method as proposed,

[0048] FIG. 2 shows an exemplary embodiment of a device as proposed,

[0049] FIG. 3 shows an exemplary timing diagram for the method and the device as proposed,

[0050] FIG. 4 shows an exemplary packet for short range radio signal transmission, and

[0051] FIG. 5 shows an exemplary scenario for hybrid localization.

[0052] FIG. 1 shows an exemplary embodiment of a method as proposed.

[0053] The method for hybrid localization in a first area and in a second area comprises the following steps:

[0054] A: operating a device in a first mode of operation, while the device is in the first area in which wireless communication is available,

[0055] B: detecting that the device transitions from the first area to the second area in which short range radio signal transmission is available,

[0056] C: switching the device to a second mode of operation upon detection that the device transitions from the first area to the second area.

[0057] Therein in the first mode of operation the device uses a first technology for localization. In the second mode of operation the device uses at least a second technology for localization in which the device emulates short range radio signal transmission during at least one idle period of the wireless communication.

[0058] In step A the device operates in the first mode of operation using the first technology for localization, while being in the first area, or environment, or location. In the first area wireless communication is available. Consequently, the device is engaged in bidirectional wireless communication, especially in bidirectional cellular communication, for example according to a 3GPP standard like LTE, transmitting and receiving messages to and from a base station. For localization the first technology is used, for instance, a cellular or wireless communication technology, or a separate GNSS service.

[0059] In step B the device detects a transition to the second area in which the short range radio signal transmission, for example Bluetooth, especially BLE 5.1, is available. For this detection one or more of the following mechanisms may be employed: evaluating the cell ID, using a geo-fencing service, using RF fingerprinting or relying on the GNSS data.

[0060] In step C the device switches to the second mode of operation and starts emulating the short range radio signal transmission during one or more idle periods of the wireless communication. For example, BLE 5.1 direction finding packets are sent in periods in which no transmission on the wireless communication, or cellular communication, occurs. For these idle periods either discontinuous reception, DRX, or enhanced/extended DRX, eDRX, or cDRX as defined in 3GPP standards, or power save mode, PSM, or a wake-up signal duration is employed. Optionally, a duration of said idle period is adjusted by way of negotiation at the beginning of step C, i.e. while entering the second mode of operation. Subsequently, one or more BLE direction finding packets are sent out by the device using the cellular communication means.

[0061] In other words, in the second mode of operation the device emulates a BLE 5.1 tag.

[0062] By reusing the wireless or cellular communication capability already implemented in the device for short range radio signal transmission like BLE, the form factor and bill of material of the device are reduced.

[0063] Optionally, the method may also comprise step D in which the device detects a transition from the second area back to the first area, turns off the second mode of operation and returns to the first mode of operation. As in the first area localization using the short range radio signal transmission is not available, e.g. due to lack of Bluetooth coverage, the BLE 5.1 emulation can be stopped.

[0064] By using the short range radio signal transmission for localization, the accuracy of the localization can be improved.

[0065] FIG. 2 shows an exemplary embodiment of a device as proposed. The device 10 is configured to be operated in the first mode of operation while the device 10 is in a first area in which wireless communication is available. The device 10 is further configured to be operated in the second mode of operation while the device 10 is in the second area in which short range radio signal transmission is available. In the first mode of operation the device is configured to use a first technology for localization. In the second mode of operation the device 10 is configured to use at least a second technology for localization. The second technology comprises emulating short range radio signal transmission during at least one idle period of the wireless communication.

[0066] In an exemplary implementation the device 10 is configured to execute the method as proposed, for example the method as depicted in FIG. 1.

[0067] According to one implementation possibility which is depicted in FIG. 2, the device 10 comprises a wireless modem 20 and a processing unit 30. The wireless modem 20 is configured to provide bidirectional wireless communication capabilities according to a wireless communication standard, e.g. as defined by the 3GPP, at least in the first mode of operation.

[0068] Said wireless communication standard comprises, for example, a cellular communication standard, like 3G or LTE/4G. The processing unit 30 is configured to provide at least one packet having localization enabling information to the wireless modem 20 in the second mode of operation. The packet conforms to the short range radio signal transmission. An example of such a packet is depicted in FIG. 4 and will be described further below.

[0069] The processing unit 30 may furthermore fulfil the tasks of a digital baseband circuit as known by those skilled in the art. The processing unit 30 may be implemented as a software module or component.

[0070] In the example of FIG. 2 the wireless modem 20 is implemented by an analogue front end circuit 21 and an analogue baseband circuit 22, which are connected to each other.

[0071] Furthermore, in the example of FIG. 2 the device 10 has an RF port 11 for connecting an antenna.

[0072] The wireless modem 20 provides wireless or cellular transmission capabilities in the second mode of operation and also optionally in the first mode of operation. For this, the analogue baseband circuit 22 performs cellular transmission and reception of packets provided by the processing unit 30. Additionally, in the second mode of operation for the emulation the analogue baseband circuit 22 provides analogue baseband transmission capabilities in accordance with the wireless communication technology for the short range radio transmission, i.e. for the Bluetooth direction finding packets using, amongst others, digital-to-analogue converters. The analogue front end circuit 21 realizes the functions of an analogue radio frequency front end as known to those skilled in the art for providing wireless, especially cellular bidirectional communication functionality. In addition, the analogue front end circuit 21 in the second mode of operation provides up conversion of BLE 5.1 packets to the BLE advertising frequency channels, e.g. in the 2.45 GHz ISM band, and appropriate output power as required by the BLE 5.1 specification.

[0073] In short, in the second mode of operation the transmitter chain or transmitter, Tx, functionality as represented by the analogue baseband circuit 22 and the analogue front end circuit 21 is reused for transmission of BLE 5.1 direction finding packets during the emulation.

[0074] In more detail, an oscillator which forms part of the analogue front end circuit 21 is tuned to each of the three Bluetooth advertising channels for sending direction finding packets in DRX or eDRX periods or during power save mode of the cellular telecommunication technology.

[0075] In other words, in the second mode of operation, the wireless modem 20 transmitter circuitry is not used for transmission of wireless communication related messages, but for sending packets according to the short range radio signal transmission. The receiver circuitry of the wireless modem 20 may or may not be switched off in the second mode of operation and may or may not listen to or receive messages on the wireless communication channels, for example paging messages or downlink, DL, control messages. In case frequency bands used for the wireless communication and the short range radio transmission do not overlap, which is the case when using LTE for wireless communication and BLE, especially BLE operating in 2.4 GHz frequency band, for short range radio signal transmission, the receiver circuitry of the wireless modem 20 may remain on. In case the frequencies overlap, which is the case, for instance, when using LTE for wireless communication and WiFi or UWB for short range radio signal transmission, the receiver circuitry of the wireless modem 20 shall be switched off. For example, the band from 5.1 GHz up 7.1 GHz is mainly used for WiFi and UWB, but also for LTE as well as emerging 5G NR-U.

[0076] FIG. 3 shows an exemplary timing diagram for the method and the device as proposed. Activity of the device, especially the wireless modem, is shown in relation to time t. Method steps A, B, C and D are also depicted on the time axis.

[0077] Between approximately point in time t1 and point in time t2 the device is operated in the first mode of operation performing method step A. The wireless modem may be engaged in bidirectional cellular communication as described above. At an instance between point in time t2 and point in time t3 transition from the first area to the second area is detected according to method step B. Consequently, at point in time t3 according to method step C the second mode of operation is switched on and emulation of the short range radio signal transmission is started. The period or timespan between point in time t3 and point in time t4 represents an idle period of the wireless or cellular communication which is reused for sending one or more BLE 5.1 direction finding packets. At an instance between point in time t4 and point in time t5 the device detects transition from the second area to the first area and turns off the emulation to operate in the first mode of operation according to method step D. Between points in time t5 and t6 another period of executing the first mode of operation follows with communication activity on the wireless or cellular communication network, i.e. information exchange with, for example, a base station. Between points in time t6 and t7 transition from the first area to the second area is detected once again and method step B is performed. Between points in time t7 and t8 the device operates in the second mode of operation emulating a BLE 5.1 tag's behavior in accordance with method step C. After point in time t8 the device detects another transition back to the first area and reenters into the first mode of operation as defined in method step D.

[0078] Similarly, a guard period of LTE-M or narrow band internet of things, NB-IoT, may be used for transmission of Bluetooth 5.1 direction finding packets.

[0079] FIG. 4 shows an exemplary packet for short range radio signal transmission. Especially the structure of a BLE 5.1 direction finding packet is depicted. Starting from the left side with the least significant bit, LSB, to the right side with the most significant bit, MSB, the packet has a preamble of one or two octets, an access address of 4 octets, a packet data unit, PDU, having 2 to 258 octets, a cyclic redundancy check, CRC, having three octets, and a constant tone extension, CTE, of 16 to 160 microseconds.

[0080] It can be discerned that the direction finding packet appends a CTE to the data provided with the PDU. The CTE has a constant frequency at the carrier frequency of the advertisement channel employed plus 250 KHz. The minimum time to send a direction finding packet is mainly based on the preamble and access address, not on the CTE time length. The CTE therein is an example for the localization enabling information.

[0081] FIG. 5 shows an exemplary scenario for hybrid localization. The device 10 is shown, which transitions back and forth between the first area 1 and the second area 2. In the second area 2 the device 10 is in the second mode of operation, as detailed above, sending e.g. BLE 5.1 direction finding packets using its wireless modem. Said direction finding packets are received by a first and a second anchor point 41, 42. Each of these anchor points 41, 42 performs an angle of arrival measurement and provides its measurement results to a positioning engine 50. The positioning engine 50 converts these measurement results and optionally additional RSSI measurement information to determine the position of the device 10. Said information may be provided to and used by an exemplary PC application implemented on a PC 60. As soon as the device 10 transitions to the first area 1, the first technology for localization, for example a cellular telecommunication technology or a GNSS service, is employed for determining the position of the device 10.

[0082] Hybrid and seamless localization of the device 10 is enabled up to a submeter accuracy in the second area 2 by using the method as proposed. Additionally, the device 10 can be realized with reduced form factor compared with the state of the art.

[0083] It will be appreciated that the invention is not limited to the disclosed embodiments and to what has been particularly shown and described hereinabove. Rather, features recited in separate dependent claims or in the description may advantageously be combined. Furthermore, the scope of the invention includes those variations and modifications which will be apparent to those skilled in the art and fall within the scope of the appended claims. The term “comprising” used in the claims or in the description does not exclude other elements or steps of a corresponding feature or procedure. In case that the terms “a” or “an” are used in conjunction with features, they do not exclude a plurality of such features. Moreover, any reference signs in the claims should not be construed as limiting the scope.

REFERENCE LIST

[0084] A, B, C, D step [0085] 1, 2 area [0086] 10 device [0087] 11 RF port [0088] 20 wireless modem [0089] 21 analogue front end circuit [0090] 22 analogue baseband circuit [0091] 30 processing unit [0092] t1, t2, . . . , t8 point in time [0093] 41, 42 anchor point [0094] 50 positioning engine [0095] 60 PC