Patent Publication Number: US-2011076946-A1

Title: Method, mobile terminal, transponder device and system for monitoring an object with respect to the mobile terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of priority to U.S. Provisional Patent Application No. 61/235,446, filed on Aug. 20, 2009, and entitled “Method, Mobile Terminal, Transponder Device And System For Monitoring An Object With Respect To The Mobile Terminal,” and to European Patent No. 09010704.6, filed Aug. 20, 2009. 
    
    
     FIELD 
     The invention relates to a method, a mobile terminal, a transponder device and a system that allows the monitoring of an object with respect to the mobile terminal. 
     BACKGROUND 
     Therapy to patients suffering especially from chronic diseases usually takes a long period of time. Such persons require permanent medical treatment, especially by means of drugs or medicines to be administered in regular intervals. Severe consequences can occur if the administration of such drugs or medicines is not performed properly. So far, a patient needs to remember to always take along such an essential drug or medicine in the event he or she, e.g., leaves his or her home or another location. 
     In case a patient unintentionally forgets to take along such a drug or medicine resulting in a medical emergency, emergency calling systems are known that aim at providing help to such patients. However, such systems usually require reaching a fixed line telephone or an associated device. 
     Presently, there are many different types of transponder systems known, examples of which include contactless smart cards or electronic labels. A characteristic hitherto common to so-called passive transponders or transponder devices of various designs is that they first receive energy from an emitting terminal (also known as the base station, reader station or reader), with which they then communicate. The energy is supplied by the terminal in the form of an alternating electromagnetic field. With an antenna or a coil, the transponder absorbs a portion of the energy of the electromagnetic field and thereby supplies its electronic circuits. The frequency ranges of the alternating field are generally in the order of about 100 KHz to a few GHz. 
     Furthermore, so-called active transponders or transponder devices are known, e.g. the so-called RuBee or ZigBee transponders. Such an active transponder has a battery from which it receives the electrical operating energy required for transmission. In this case, an activation radio frequency signal (received by the transponder) can be used for addressing purposes, to wake up and thus to activate the transponder. RuBee denotes a bi-directional protocol based on the Institute of Electrical and Electronics Engineers (IEEE) 1902.1 standard and operates at frequencies below 450 kHz (optimally at a low frequency band of 132 kHz). RuBee has a transmission range of up 15 m to 30 m in radius and supports a data rate of up to 100 Kbps, and RuBee waves can pass through water and ground. ZigBee denotes communication protocols based on the IEEE 802.15.4 standard, and operates in the Industrial, Scientific and Medical (ISM) radio bands of 868 MHz, 915 MHz, and 2.4 GHz. ZigBee has a transmission range of 10 to 20 m in radius and supports a data rate of 20 to 250 Kbps. 
     Generally, such transponders or transponder devices operate in the radio frequency range from 3 to 30 MHz, although appropriate different wavelengths, such as low frequency from 30 kHz to 300 kHz, ultra-high frequency from 300 MHz to 3 GHz or microwave frequencies above 3 GHz may also be used depending on the desired range or coverage area. 
     SUMMARY 
     In an embodiment, the present invention provides a system for monitoring an object. A transponder device is associated with the object and includes an acceleration sensor operable to provide an acceleration signal. The transponder device is operable to emit a radio signal based on the acceleration signal. A mobile terminal having a short range radio interface and a secondary radio interface, comprising a wireless network interface, is operable to communicate with the transponder device using the short range radio interface. The mobile terminal is operable to receive the radio signal so as to indicate that the object is present within a coverage area defined by the short range radio interface. The mobile terminal is operable to emit a first alert signal when the radio signal is not received by the mobile terminal within a first predetermined time interval. The transponder device is operable to repeatedly emit the radio signal during a second predetermined time interval when the radio signal is not received by the mobile terminal within the first predetermined time interval. The mobile terminal is operable to emit a second alert signal and communicate with a party of a communication network when the radio signal is not received by the mobile terminal within the second predetermined time interval. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically shows an example of a system for monitoring an object with respect to a mobile terminal. 
         FIGS. 2 and 3  schematically show two different modes of communication between a transponder device and the mobile terminal according to an embodiment of the invention. 
         FIGS. 4 and 5  schematically show two examples of the transponder device according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the invention provides a method of preventing such above described medical emergency situations by alerting a patient of the fact that he or she is moving beyond a certain distance from his or her essential drugs or medicines. Additional embodiments of the invention provide a method of alerting a person of the fact that he or she is moving beyond a certain distance from a special object essential to his or her well-being. 
     One embodiment of the invention provides a method, a mobile terminal, a transponder device and a system that allows the monitoring of an object, especially the presence of the object, with respect to the mobile terminal such that a user can be informed about the fact that he or she is moving beyond a certain distance from such an object. 
     One embodiment of the invention provides a system for monitoring an object with respect to a mobile terminal, the system comprising the mobile terminal and a transponder device, the mobile terminal comprising a short range radio interface, the mobile terminal being operable to communicate with the transponder device via the short range radio interface, wherein the object comprises the transponder device or is attached to the transponder device, wherein the mobile terminal is operable for receiving a radio signal emitted by the transponder device indicating that the object is present within the coverage area of the short range radio interface of the mobile terminal, wherein the mobile terminal has a further radio interface, the further radio interface being one of a wireless wide area network interface or a wireless local area network interface, wherein the transponder device comprises an acceleration sensor operable to provide an acceleration signal, wherein in case that the radio signal is not received within a predetermined time interval by the mobile terminal, the mobile terminal is provided such that an alert signal is output by the mobile terminal, wherein the radio signal emitted by the transponder device is emitted repeatedly within a further predetermined time interval, wherein in case that the object is detected as not being present within the coverage area of the short range radio interface of the mobile terminal, a communication of the mobile terminal with another party of a communications network and a transmission of the alert signal is provided, wherein the emission of the radio signal by the transponder device depends on the acceleration signal. 
     One embodiment of the inventionprovides—by means of the mobile terminal receiving the radio signal from the transponder device—the mobile terminal receives the information that the transponder device is located within a comparably short distance from the mobile terminal. This means that if, e.g., the transponder device is either integrated in, e.g., a packaging of an essential drug or medicine or attached to an essential drug or medicine, it is possible to alert a user of the fact that at least no radio signal has been received by the mobile terminal for a certain time interval. If the assumption is met that the mobile terminal is generally carried by the user relatively closely to his or her body or that the mobile terminal is virtually always taken along by the user (e.g. in a bag or the like), the failure (of the mobile terminal) to receive the radio signal from the transponder device (within a predetermined time interval) is a strong indicator that the distance between the transponder device (and hence the essential drug or medicine or other object) on the one hand and the mobile terminal (and hence the user) on the other hand exceeds the range of the short range radio interface which can be of the order of magnitude of a few meters until a few hundreds of meters, being preferably between 5 meters and 100 meters and more preferably between 10 meters and 30 meters. If the user is alerted of such a situation (i.e. that the essential drug or medicine is further away than the range or the short range radio interface), it is usually possible without too much effort to get the essential drug or medicine or to take along the essential drug or medicine because the distance between the user and the mobile terminal is comparably low. The alert is usually done by means of an alert signal generated by the mobile terminal. The alert signal can be any acoustical and/or optical and/or mechanical (vibrational) signal of the mobile terminal that can be detected by the user, e.g. a beeping sound and/or a melody and/or an illuminated LED and/or a flash light and/or a vibrational signal. According to one embodiment of the invention, the mobile terminal therefore comprises a corresponding output device, i.e. an acoustic output device like a loudspeaker, and/or an optical output device like an LED, and/or a mechanical output device like a vibration generator. 
     In one embodiment of the invention, the predetermined time interval is a time interval of, e.g., several seconds to several minutes or several hours. The definition of the predetermined time interval might depend, e.g., on the individual health situation of the user and/or on the individual administration scheme of the drug or the medicine. 
     In one embodiment of the invention, the radio signal emitted by the transponder device is emitted repeatedly within a further predetermined time interval, e.g. every several seconds or every several minutes or every several hours. The definition of the further predetermined time interval might also depend, e.g., on the individual health situation of the user and/or on the individual administration scheme of the drug or the medicine. 
     By means of adjusting the preferred time interval and the further preferred time interval, it is possible to provide for an effective alerting of the user by the mobile terminal in case the radio signal is not received by the mobile terminal, i.e. in case the object is detected as not being present within the coverage area of the short range radio interface of the mobile terminal. For example, it is possible that the predetermined time interval is comparable to the further predetermined time interval, which means that every radio signal emitted by the transponder device has to be received by the mobile terminal, otherwise the alert signal is generated by the mobile terminal. Alternatively, it is also possible that the predetermined time interval is longer (e.g. twice as long or thrice as long) than the further predetermined time interval, which means that at least one occurrence (or two subsequent occurrences) of the radio signal emitted by the transponder device and not received by the mobile terminal is/are tolerated without an alert signal being generated. The first alternative provides a higher level of security of (quickly) detecting a comparably high distance between the transponder device and the mobile terminal and the second alternative provides a lower probability of false positive alert signals. 
     It is also possible according to one embodiment of the invention that the alert signal varies dependent on how many occurrences of the radio signal have not been received by the mobile terminal. This means that a first predetermined time interval and a second predetermined time interval are defined and the mobile terminal generates a first alert signal if the radio signal is not received within a first predetermined time interval by the mobile terminal and that the mobile terminal generates a second alert signal if the radio signal is not received within a second predetermined time interval by the mobile terminal. For example, it is possible according to an embodiment of the invention that only an optical alert signal (as the first alert signal) is generated in case the radio signal has not been received within the first predetermined time interval (corresponding, e.g., to the further preferred time interval, i.e. the emission interval of the radio signal emitted by the transducer device) and that an optical and an acoustic alert signal (as the second alert signal) is generated in case the radio signal has not been received within the second predetermined time interval (corresponding, e.g., to twice the further preferred time interval, i.e. twice the emission interval of the radio signal emitted by the transducer device). 
     In one embodiment of the invention, the mobile terminal has a further radio interface, the further radio interface being one of a wireless wide area network interface or a wireless local area network interface, wherein the method further comprises the step of the mobile terminal communicating with another party of a communications network and transmitting the alert signal in case the object is detected as not being present within the coverage area of the short range radio interface of the mobile terminal. 
     In one embodiment of the invention according to which the mobile terminal comprises the further radio interface, it is possible not only to transmit the alert signal to the user carrying the mobile terminal (i.e. by means of the output device of the mobile terminal) but (additionally and/or alternatively) transmitting the alert signal to another party or location, e.g., by means of a communication of the mobile terminal via the further radio interface with a base station. 
     One embodiment of the invention provides that, e.g., the generation of the alert signal to the user of the mobile terminal (i.e. any acoustical and/or optical and/or mechanical (vibrational) signal of the mobile terminal that can be detected by the user) corresponds to the first alert signal and that the mobile terminal communicating with another party of a communications network (and transmitting the alert signal in case the object is detected as not being present within the coverage area of the short range radio interface of the mobile terminal) corresponds to the second alert signal. 
     In one embodiment of the invention, the other party of the communications network might be, e.g., a neighbor of the user and/or an emergency center. The other party can be alerted automatically, i.e. the information that the user of the inventive system is out of reach of essential drugs or medicines. Furthermore, it is possible that additional information is transmitted to the other party such as: 
     an information regarding the geographical location of the user of the inventive system, and/or 
     an information about the name or the nature of the essential drug or medicine or another information about the object to be monitored. Additionally, the further steps in handling the alert signal depend on the nature of the object to be monitored, e.g. on the nature of the drug or medicine. 
     Furthermore, it is possible in one embodiment of the invention that the communication between the mobile terminal and the other party is performed by means of a voice communication link (voice call) and/or by means of a data communication link, e.g. by means of an SMS (Short Message Service) service. It is furthermore possible that the further radio interface does not require a specified fixed line telecommunication equipment such that the inventive system can be used wherever the further radio interface is available. 
     In one embodiment of the invention, it is provided that the transponder device comprises an acceleration sensor operable to provide an acceleration signal, wherein the emission of the radio signal by the transponder device depends on the acceleration signal. 
     In one embodiment of the invention it is possible to perform the method in an efficient way, especially in view to reduce the consumption of energy within the transponder device. In dependency of the acceleration signal, it is possible that the transponder device emits the radio signal such that the information is transmitted to the mobile terminal that no acceleration (of the transponder device) has occurred for a certain period of time. According to one embodiment of the invention, this information can be used to reduce the number of transmissions of the radio signal (during a certain period of time) from the transponder device to the mobile terminal, thus reducing the consumption of energy in the transponder device and possibly enhancing the life time of the battery (or other source of energy) of the transponder device. 
     In one embodiment of the invention, it is possible that the emission of a further radio signal by the mobile terminal is provided, the radio signal emitted by the transponder device being received by the mobile terminal in response of the further radio signal. 
     In the case of the transponder device being an active transponder device, it is also possible that the further radio signal serves as a paging signal. This means that the radio signal of the transponder device is emitted in response to the further radio signal of the mobile terminal. In this case it is possible to provide a higher level of communication security (and hence a higher reliability of the inventive method) as it is possible, e.g., that the mobile terminal sends the further radio signal in case the mobile terminal has missed an expected radio signal (to be sent by the transponder device). In this situation a verification procedure (i.e. prompting the transponder device to emit the radio signal immediately once more) can lead to a quicker determination whether the transponder device (and hence the object) has been moved out of the range of the short range radio interface of the mobile terminal (and hence a quicker possibility to alert the user). 
     In one embodiment of the invention, it is possible that the mobile terminal comprises a further acceleration sensor operable to provide a further acceleration signal, wherein the emission of the further radio signal by the mobile terminal depends on the further acceleration signal. 
     In one embodiment of the invention it is possible to provide an efficient inventive system perform or to perform the inventive method in an efficient way, one benefit of which is to reduce the consumption of energy within the transponder device and within the mobile terminal. In dependency of the further acceleration signal, it is possible that the mobile terminal emits the further radio signal such that the information is transmitted to the transponder device that no acceleration (of the mobile terminal) has occurred for a certain period of time. According to one embodiment of the invention, this information can be used to reduce the number transmissions of the radio signal (during a certain period of time) from the transponder device to the mobile terminal, thus reducing the consumption of energy in the transponder device and possibly enhancing the life time of the battery (or other source of energy) of the transponder device. For example, it is possible that both the mobile terminal and the transponder device do not emit the radio signal and the further radio signal (for a comparably long time) provided that both the acceleration signal and the further acceleration signal suggests that no (measurable) acceleration has occurred to the mobile terminal and to the transponder device. 
     In another embodiment of the invention all functions of the mobile terminal that are not required for the communication via the short range radio interface can be switched off, either actively or in dependency of the further acceleration signal. Thereby, the energy consumption of the mobile terminal can be reduced to a minimum. 
     The invention also relates to a method for monitoring an object with respect to a mobile terminal, the mobile terminal having a short range radio interface, the object comprising a transponder device or being attached to a transponder device, the transponder device being operable to communicate with the mobile terminal via the short range radio interface, wherein the mobile terminal has a further radio interface, the further radio interface being one of a wireless wide area network interface or a wireless local area network interface, wherein the transponder device comprises an acceleration sensor operable to provide an acceleration signal, the method comprising the steps of 
     the mobile terminal receiving a radio signal emitted by the transponder device indicating that the object is present within the coverage area of the short range radio interface of the mobile terminal, 
     the mobile terminal outputting an alert signal if the radio signal is not received within a predetermined time interval by the mobile terminal, 
     the radio signal emitted by the transponder device being emitted repeatedly within a further predetermined time interval, 
     the mobile terminal communicating with another party of a communications network and transmitting the alert signal in case the object is detected as not being present within the coverage area of the short range radio interface of the mobile terminal, 
     the transponder device emitting the radio signal dependent on the acceleration signal. 
     In one embodiment of the invention, it is thereby possible that—by means of the mobile terminal receiving the radio signal from the transponder device—the mobile terminal receives the information that the transponder device is located within a comparably short distance from the mobile terminal. 
     In one embodiment of the invention, it is possible that the emission of a further radio signal by the mobile terminal is provided, wherein the method comprises the step of the mobile terminal emitting the further radio signal, the radio signal emitted by the transponder device being received by the mobile terminal in response of the further radio signal. 
     In one embodiment of the invention the mobile terminal comprises a further acceleration sensor operable to provide a further acceleration signal, and wherein the method comprises the further step of the mobile terminal emitting the further radio signal dependent on the further acceleration signal. 
     According to another embodiment of the invention, it is provided that the method further comprises the step of the mobile terminal identifying the transponder device, the step of the mobile terminal identifying the transponder device being performed prior to the reception of the radio signal by the mobile terminal. The identification of the transponder device is possible to perform, e.g., by means of inputting an identification number into the mobile terminal (for example by means of an input means like a keyboard or a touch screen or the like) and/or by means of recognizing a bar code (for example by means of a scanner or by means of an image capturing device like a camera or the like). 
     If more than one transponder devices exist in the environment of mobile terminal which are unknown to the mobile terminal (i.e. for which no identifications procedure has been performed) and one transponder device of such a plurality of transponder devices is to be identified by the mobile terminal, one strategy consists in reducing the power of the further radio signal and/or the sensitivity of for the reception of the radio signals emitted by the transponder devices such that only one transponder device (of the plurality of transponder devices) is reached by the mobile terminal or is seen by the mobile terminal. 
     In one embodiment of the invention, it is possible that the step of identifying the transponder device also encompasses the definition of the object to be monitored by the inventive method. In case the transponder device is attached to the object (i.e. the object like a drug packaging or the like is not connected to the transponder device (e.g. during manufacture of the object) in a permanent fashion), the nature of the object is unknown to the mobile terminal. Therefore, the definition of the object to be monitored comprises, e.g., to input a product code of the object to be monitored in the mobile terminal. The definition of the object can be performed, e.g., by means of inputting an identification number into the mobile terminal (for example by means of an input means like a keyboard or a touch screen or the like) and/or by means of recognizing a bar code (for example by means of a scanner or by means of an image capturing device like a camera or the like). 
     In one embodiment of the invention, it is possible that the bar code information is transmitted via the further radio interface such that the mobile terminal receives the relevant information regarding the transponder device and/or regarding the product. 
     Dependent on the nature of the object to be monitored, it is possible according to one embodiment of the invention to store different alerting schemes corresponding to different risk levels or risk classes such that, e.g., the alert signal related to less essential drug or medicine (or other object) is handled differently to the alert signal indicating that a more essential drug or medicine (or other object) is out of reach of the user. 
     The invention also relates to a transponder device for use with an embodiment of the invention, the transponder device being operable to communicate with a mobile terminal via a short range radio interface, the mobile terminal comprising the short range radio interface, wherein an object comprises the transponder device or is attached to the transponder device, wherein the transponder device is operable for transmitting a radio signal to the mobile terminal indicating that the object is present within the coverage area of the short range radio interface of the mobile terminal, wherein the transponder device comprises an acceleration sensor, wherein the acceleration sensor is operable to provide an acceleration signal, and wherein the transponder device emits the radio signal dependent on the acceleration signal. 
     The invention further relates to a mobile terminal for use with an embodiment of the invention, the mobile terminal comprising a short range radio interface, the mobile terminal being operable to communicate with a transponder device via the short range radio interface, wherein an object comprises the transponder device or is attached to the transponder device, wherein the mobile terminal is operable for receiving a radio signal emitted by the transponder device indicating that the object is present within the coverage area of the short range radio interface of the mobile terminal. 
     In one embodiment, the mobile terminal has a further radio interface, the further radio interface being one of a wireless wide area network interface or a wireless local area network interface, wherein the method further comprises the step of the mobile terminal communicating with another party of a communications network and transmitting the alert signal in case the object is detected as not being present within the coverage area of the short range radio interface of the mobile terminal. 
     The invention further relates to program comprising a computer readable program code and to a computer program product comprising a computer readable program code for controlling a mobile terminal, the mobile terminal comprising a short range radio interface, the mobile terminal being operable to communicate with a transponder device via the short range radio interface, wherein an object comprises the transponder device or is attached to the transponder device, wherein the mobile terminal is operable for receiving a radio signal emitted by the transponder device indicating that the object is present within the coverage area of the short range radio interface of the mobile terminal. 
     These and other characteristics, features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, embodiments of the invention. The description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings. 
     The invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. 
     According to an embodiment of the invention, an object can be monitored with respect to a mobile terminal. 
       FIG. 1  schematically shows an example of a system for monitoring an object  10  with respect to the mobile terminal  20 . The object  10  is either attached to a transponder device  11  or the object  10  is manufactured with the transponder device  11  integrated in the object  10  so that the object  10  comprises the transponder device  11 . The mobile terminal  20  comprises a short range radio interface  22  and the transponder device  11  is operable to communicate with the mobile terminal  20  via the short range radio interface  22 . The short range radio interface  22  is in one embodiment, a radio interface suitable to be used between the mobile terminal  20  and the transponder device  11 , the mobile terminal  22  acting (by means of the short range radio interface  22 ) as reader station to the transponder device  11 . Examples of the short range radio interface and short range communication link  22 ′ established between the mobile terminal  20  and the transponder device  11  include: 
     a RFID short range radio interface, 
     a NFC (Near Field Communication) short range radio interface, 
     a RuBee short range radio interface. 
     According to one embodiment of the mobile terminal  20 , the mobile terminal  20  comprises also a further radio interface  21  operable to connect the mobile terminal  20  to another party  31  of a communications network  30 . The further radio interface  21  is in one embodiment one of a wireless wide area network interface or a wireless local area network interface. Examples of the further radio interface  21  and further communication link  21 ′ established between the mobile terminal  20  and the communications network  30  include: 
     a cellular mobile communications network interface, 
     a WLAN (Wireless Local Area Network) interface. 
     In one embodiment of the invention, the mobile terminal  20  comprises a memory device (not shown) such that data related to the transponder device  11  monitored or related to a plurality of transponder devices  11  monitored are stored in the memory device. In case of an emergency situation necessitating a communication via the further radio interface  21 , such data related to the transponder device  11  can be transmitted to the communications network  30  and/or to the other party  31 . Such data can, e.g., comprise monitoring data such as: 
     a time stamp of the last contact to the transponder device  11  and/or 
     the geographical coordinates of the mobile terminal at present and/or at the time of the last contact to the transponder device  11 . 
     In one embodiment of the invention, the mobile terminal stores information about any established communication link to the other party  31  and/or about any transmitted data. 
       FIGS. 2 and 3  schematically show two different modes of communication between the transponder device  11  and the mobile terminal  20  according to one embodiment of the invention. 
       FIG. 2  shows the case of the transponder device  11  being an active transponder. The transponder device  11  emits a radio signal  13  which is received by the mobile terminal  20 . The radio signal  13  is in one embodiment emitted in regular time intervals (also called further predetermined time interval in the context of one embodiment of the invention). The transponder device  11  does not need to be incited by the mobile terminal  20  to emit the radio signal  13 . Of course, it is possible according to the invention that the transponder device  11  is incited by the mobile terminal  20  to emit the radio signal  13  (not shown in  FIG. 2 ). 
       FIG. 3  shows the case of the transponder device  11  being a passive transponder. The transponder device  11  emits the radio signal  13  in response of a further radio signal  23  emitted by the mobile terminal  20  to the transponder device  11 . The transponder device  11  uses the energy of the further radio signal  23  to generate the radio signal  13  which is received by the mobile terminal  20 . The further radio signal  23  and thus the radio signal  13  is in one embodiment emitted in regular time intervals (also called further predetermined time interval in the context of an embodiment of the invention). By means of the further radio signal  23 , the transponder device  11  is always incited by the mobile terminal  20  to emit the radio signal  13 . 
       FIGS. 4 and 5  schematically show two examples of the transponder device  11  according to the invention. 
       FIG. 4  shows the case of the transponder device  11  being an active transponder. The transponder device  11  comprises a source of energy  16 , e.g. a battery. The transponder device  11  emits the radio signal  13  which is received by the mobile terminal  20 . In one embodiment of the invention, the transponder device  11  comprises an acceleration sensor  15 . 
       FIG. 5  shows the case of the transponder device  11  being a passive transponder. The transponder device  11  does not comprise a source of energy but receives the further radio signal  23  and uses the energy of the further radio signal  23  to generate the radio signal  13  which is received by the mobile terminal  20 . In one embodiment of the invention, the transponder device  11  comprises an acceleration sensor  15 . 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 
     Furthermore, the terms first, second, third and the like in the description and in the claims are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described of illustrated herein. 
     The present invention is not limited to the embodiments described herein; reference should be had to the appended claims.