Abstract:
A wireless power transfer system is described that includes features that allow the system to be deployed in public spaces such as airports or in commercial establishments such as restaurants or hotels to allow a user to recharge one or more portable electronic devices while away from home. In one embodiment, the system provides a secure and efficient means for obtaining required payment information from the user prior to the wireless power transfer, thereby facilitating fee-based recharging. In a further embodiment, to accommodate wireless recharging of a variety of device types and states, the system receives parameters and/or state information associated with a portable electronic device to be recharged and controls the wireless power transfer in accordance with such parameters and/or state information.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 61/150,554, filed Feb. 6, 2009, the entirety of which is incorporated by reference herein. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention generally relates to systems capable of transmitting electrical power without wires. 
         [0004]    2. Background 
         [0005]    As used herein, the term wireless power transfer refers to a process by which electrical energy is transmitted from a power source to an electrical load without interconnecting wires. Wireless power transfer is useful for applications in which instantaneous or continuous energy transfer is needed, but for which providing a wired connection is inconvenient, hazardous, or impossible. 
         [0006]    It has been observed that while electromagnetic radiation (such as radio waves) is excellent for transmitting information wirelessly, it is generally not suitable for transferring power wirelessly. For example, if power were transferred using omnidirectional electromagnetic waves, a vast majority of the power would end up being wasted in free space. Directed electromagnetic radiation such as lasers might be used to transfer power between a power source and a device, but this is not very practical and could even be dangerous. Such an approach would also require an uninterrupted line of sight between the power source and the device, as well as a sophisticated tracking mechanism when the device is mobile. 
         [0007]    For the foregoing reasons, conventional systems that transfer power wirelessly are typically based on the concept of electromagnetic induction rather than electromagnetic radiation. These systems include systems based on inductive coupling and so-called “resonant inductive coupling.” 
         [0008]    Inductive coupling refers to the transfer of energy from one circuit component to another through a shared electromagnetic field. In inductive coupling, a current running in an emitting coil induces another current in a receiving coil. The two coils are in close proximity, but do not touch. 
         [0009]    Inductive coupling has been used in a variety of systems, including but not limited to systems that wirelessly charge a battery in a portable electronic device. In such systems, the portable electronic device is placed in close proximity to a charging station. A first induction coil in the charging station is used to create an alternating electromagnetic field, and a second induction coil in the portable electronic device derives power from the electromagnetic field and converts it back into electrical current to charge the battery. Thus, in such systems, there is no need for direct electrical contact between the battery and the charging station. 
         [0010]    Some examples of various different types of charging systems based on the principle of inductive coupling are described in U.S. Pat. No. 3,938,018 to Dahl, entitled “Induction Charging System,” U.S. Pat. No. 4,873,677 to Sakamoto et al., entitled “Charging Apparatus for an Electronic Device,” U.S. Pat. No. 5,952,814 to Van Lerberghe, entitled “Induction Charging Apparatus and an Electronic Device,” U.S. Pat. No. 5,959,433 to Rohde, entitled “Universal Inductive Battery Charger System,” and U.S. Pat. No. 7,042,196 to Ka-Lai et al., entitled “Contact-less Power Transfer,” each of which is incorporated by reference as if fully set forth herein. Examples of some conventional devices that include batteries that may be recharged via inductive coupling include the Braun Oral B Plak Control Power Toothbrush, the Panasonic Digital Cordless Phone Solution KX-PH15AL and the Panasonic multi-head men&#39;s shavers ES70/40 series. 
         [0011]    Another example of a technology that supports the use of inductive coupling to wirelessly transfer power is called Near Field Communication (NFC). NFC is a short-range high frequency wireless communication technology that enables the exchange of data between devices over approximately a decimeter distance. NFC is an extension of the ISO/IEC 14443 proximity-card standard that combines the interface of a smartcard and a reader into a single device. An NFC device can communicate with both existing ISO/IEC 14443 smartcards and readers, as well as with other NFC devices, and is thereby compatible with existing contactless infrastructure already in use for public transportation and payment. The air interface for NFC is described in ISO/IEC 18092/ECMA-340: Near Field Communication Interface and Protocol-1 (NFCIP-1) and ISO/IEC 21481/ECMA-352: Near Field Communication Interface and Protocol-2 (NFCIP-2), which are incorporated by reference herein. 
         [0012]    NFC devices communicate via magnetic field induction, wherein two loop antennas are located within each other&#39;s near field, effectively forming an air-core transformer. In a passive communication mode, an initiator device provides a carrier field and a target device answers by modulating the existing field. In this mode, the target device may draw its operating power from the initiator-provided electromagnetic field. 
         [0013]    “Resonant inductive coupling” refers to a more recently-publicized type of inductive coupling that utilizes magnetically-coupled resonators for wirelessly transferring power. In a system that uses resonant inductive coupling, a first coil attached to a sending unit generates a non-radiative magnetic field oscillating at MHz frequencies. The non-radiative field mediates a power exchange with a second coil attached to a receiving unit, which is specially designed to resonate with the field. The resonant nature of the process facilitates a strong interaction between the sending unit and the receiving unit, while the interaction with the rest of the environment is weak. Power that is not picked up by the receiving unit remains bound to the vicinity of the sending unit, instead of being radiated into the environment and lost. 
         [0014]    Resonant inductive coupling is said to enable relatively efficient wireless power transfer over distances that are a few times the size of the device to be powered, therefore exceeding the performance of systems based on non-resonant inductive coupling. An example of a wireless power transfer system based on resonant inductive coupling is described in U.S. Patent Application Publication No. 2007/0222542 to Joannopoulos et al., entitled “Wireless Non-radiative Energy Transfer,” which is incorporated by reference herein. 
         [0015]    Given the explosive growth in the use of portable electronic devices such as laptop computers, cellular telephones and portable media devices, it is anticipated that there will be a strong demand for systems that facilitate the wireless recharging of power sources based on various types of near field inductive coupling such as those described above. Indeed, it may be deemed desirable to make such systems available in public spaces such as airports or in commercial establishments such as restaurants or hotels to allow users to recharge their portable electronic devices while away from home. 
         [0016]    Such wireless transfer of power in public or commercial environments may be made available to users for a fee. However, in order to achieve this, the wireless power transfer system must provide a secure and efficient way of obtaining requisite payment information from a user prior to performing the wireless power transfer. Still further, to accommodate wireless recharging of a variety of device types and states, the desired system should be able to receive parameters and/or state information associated with a portable electronic device to be recharged and to control the wireless power transfer in accordance with such parameters and/or state information. 
         [0017]    Unfortunately, none of the foregoing systems based on inductive coupling or resonant inductive coupling provide such features. For example, although NFC devices may use magnetic field induction to wirelessly transfer power as well as payment information and other types of data, it does not appear that such NFC devices are designed to use the wirelessly transferred power to recharge a power source associated with a portable electronic device. Furthermore, it does not appear that such devices control the wireless power transfer based on parameters and/or state information received from the portable electronic device having a power source to be recharged. 
       BRIEF SUMMARY OF THE INVENTION 
       [0018]    As will be described in detail herein, a wireless power transfer system in accordance with an embodiment of the present invention includes features that allow the system to be deployed in public spaces such as airports or in commercial establishments such as restaurants or hotels to allow a user to recharge one or more portable electronic devices while away from home. In one embodiment, the system provides a secure and efficient means for obtaining required payment information from the user prior to the wireless power transfer, thereby facilitating fee-based recharging. In a further embodiment, to accommodate wireless recharging of a variety of device types and states, the system receives parameters and/or state information associated with a portable electronic device to be recharged and controls the wireless power transfer in accordance with such parameters and/or state information. 
         [0019]    In particular, a method for wirelessly transferring power from a charging station to a portable electronic device is described herein. In accordance with the method, a wireless communication link is established with the portable electronic device. Payment information is then received from the portable electronic device via the wireless communication link. Responsive to receiving the payment information, power is transferred to the portable electronic device over a wireless power link. 
         [0020]    In accordance with the foregoing method, the wireless communication link may be established in accordance with one of a Near Field Communication (NFC) protocol, a Bluetooth™ protocol, a ZigBee® protocol, or an IEEE 802.11 protocol. 
         [0021]    The foregoing method may further include establishing the wireless power link. The wireless power link may be established based on inductive coupling or on resonant inductive coupling. The wireless communication link and the wireless power link may also be established via the same inductive link. The foregoing method may further include monitoring an amount of power wirelessly transferred to the portable electronic device and charging a user of the portable electronic device based on the monitored amount. 
         [0022]    A charging station is also described herein. The charging station includes a transceiver, a communication link manager connected to the transceiver, and a power link manager connected to the communication link manager and the transceiver. The communication link manager is configured to establish a wireless communication link with a portable electronic device via the transceiver and to receive payment information from the portable electronic device via the wireless communication link. The power link manager is configured to establish a wireless power link with the portable electronic device via the transceiver and to transfer power to the portable electronic device over the wireless power link responsive to receipt of the payment information by the communication link manager. 
         [0023]    An additional method for wirelessly transferring power from a charging station to a portable electronic device is described herein. In accordance with the method, a wireless communication link is established with the portable electronic device. Parameters and/or state information are then received from the portable electronic device via the wireless communication link. Power is then transferred to the portable electronic device over a wireless power link, wherein the manner in which power is transferred is controlled in accordance with the parameters and/or state information. 
         [0024]    In accordance with the foregoing method, the parameters and/or state information may include a maximum safe power that may be received by the portable electronic device. The parameters and/or state information may also include an amount of power currently consumed or needed by the portable electronic device. 
         [0025]    A further charging station is also described herein. The charging station includes a transceiver, a communication link manager connected to the transceiver and a power link manager connected to the communication link manager and the transceiver. The communication link manager is configured to establish a wireless communication link with a portable electronic device via the transceiver and to receive parameters and/or state information from the portable electronic device via the wireless communication link. The power link manager is configured to establish a wireless power link with the portable electronic device via the transceiver and to transfer power to the portable electronic device over the wireless power link, wherein the manner in which power is transferred is controlled in accordance with the parameters and/or state information. 
         [0026]    A method for wirelessly receiving power from a charging station by a portable electronic device is also described herein. In accordance with the method, a wireless communication link is established with the charging station. Payment information is then transmitted to the charging station via the wireless communication link. Responsive to the receipt of the payment information by the charging station, power is received from the charging station over a wireless power link. 
         [0027]    A portable electronic device is also described herein. The portable electronic device includes a transceiver, a communication link manager connected to the transceiver, and a battery recharging unit connected to the transceiver. The communication link manager is configured to establish a wireless communication link with a charging station via the transceiver and to transmit payment information to the charging station via the wireless communication link. The battery recharging unit is configured to establish a wireless power link with the charging station via the transceiver and to receive power from the charging station over the wireless power link responsive to receipt of the payment information by the charging station. 
         [0028]    An additional method for wirelessly receiving power from a charging station by a portable electronic device is also described herein. In accordance with the method, a wireless communication link is established with the charging station. Parameters and/or state information are then transmitted to the charging station via the wireless communication link. Power is then received from the charging station over a wireless power link, wherein the manner in which power is transferred from the charging station is controlled in accordance with the parameters and/or state information. The foregoing method may further include monitoring the wireless power link to determine an amount of power transferred over the link and using the determined amount to generate the state information. 
         [0029]    A further portable electronic device is described herein. The portable electronic device includes a transceiver, a communication link manager connected to the transceiver, and a battery recharging unit connected to the transceiver. The communication link manager is configured to establish a wireless communication link with a charging station via the communication link transceiver and to transmit parameters and/or state information to the charging station via the wireless communication link. The battery recharging unit is configured to establish a wireless power link with the charging station via the transceiver and to receive power from the charging station over the wireless power link, wherein the manner in which power is transferred from the charging station is controlled in accordance with the parameters and/or state information. 
         [0030]    Further features and advantages of the invention, as well as the structure and operation of various embodiments of the invention, are described in detail below with reference to the accompanying drawings. It is noted that the invention is not limited to the specific embodiments described herein. Such embodiments are presented herein for illustrative purposes only. Additional embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
         [0031]    The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the relevant art(s) to make and use the invention. 
           [0032]      FIG. 1  is a block diagram of an example wireless power transfer system in accordance with an embodiment of the present invention. 
           [0033]      FIG. 2  depicts a flowchart of a method for wirelessly transferring power from a charging station to a portable electronic device in accordance with an embodiment of the present invention. 
           [0034]      FIG. 3  depicts a flowchart of a method for wirelessly receiving power from a charging station by a portable electronic device in accordance with an embodiment of the present invention. 
           [0035]      FIG. 4  depicts a flowchart of an additional method for wirelessly transferring power from a charging station to a portable electronic device in accordance with an embodiment of the present invention. 
           [0036]      FIG. 5  depicts a flowchart of an additional method for wirelessly receiving power from a charging station by a portable electronic device in accordance with an embodiment of the present invention. 
           [0037]      FIG. 6  is a block diagram of a wireless power transfer system in accordance with an embodiment of the present invention in which a wireless power link is established using a receiver and transmitter and a wireless communication link is established using a separate pair of transceivers. 
           [0038]      FIG. 7  is a block diagram of a wireless power transfer system in accordance with an alternate embodiment of the present invention in which a wireless communication link between a portable electronic device and a charging station is unidirectional. 
           [0039]      FIG. 8  is a block diagram of a wireless power transfer system in accordance with an alternate embodiment of the present invention in which a charging station includes a plurality of different communication link transceivers to facilitate the establishment of wireless communication links with a plurality of different types of portable electronic devices. 
       
    
    
       [0040]    The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number. 
       DETAILED DESCRIPTION OF THE INVENTION 
     A. Example Wireless Power Transfer System in Accordancer with an Embodiment of the Present Invention 
       [0041]      FIG. 1  is a block diagram of an example wireless power transfer system  100  in accordance with an embodiment of the present invention. System  100  includes a charging station  102  and a portable electronic device  104 . As will be described in more detail herein, charging station  102  is configured to wirelessly transfer power to portable electronic device  104  responsive to receipt of payment information there from. Charging station  102  is also configured to manage the wireless transfer of power to portable electronic device  104  based on certain parameters and/or state information received from portable electronic device  104 . 
         [0042]    As shown in  FIG. 1 , charging station  102  includes a power source  122  connected to a wireless power/communication link transceiver  124 . Wireless power/communication link transceiver  124  is configured to wirelessly transfer power supplied by power source  122  to a wireless power/communication link transceiver  146  associated with portable electronic device  104  via an inductive link  106 . As will be appreciated by persons skilled in the relevant art(s), such wireless power transfer may be carried out over inductive link  106  in accordance with the well-known principles of inductive coupling or resonant inductive coupling as discussed in the Background Section above. As will be further appreciated by persons skilled in the relevant art(s), the manner in which wireless power/communication link transceiver  124  and wireless power/communication link transceiver  146  are implemented will depend on the type of inductive coupling used. A variety of transceiver designs based on inductive coupling and resonant inductive coupling are available in the art and thus need not be described herein. 
         [0043]    Charging station  102  also includes a power link manager  126  connected between power source  122  and wireless power/communication link transceiver  124 . Power link manager  126  is configured to sense when wireless power/communication link transceiver  146  associated with portable electronic device  104  is inductively coupled to wireless power/communication link transceiver  124  and is thus capable of receiving power wirelessly there from. Power link manager  126  is further configured to transfer power wirelessly over inductive link  106  responsive to control signals from a communication link manager  128 . Power link manager  126  may be further configured to monitor the amount of power that is wirelessly transferred via inductive link  106  to portable electronic device  104 . 
         [0044]    Communication link manager  128  is connected both to power link manager  126  and to wireless power/communication link transceiver  124 . Communication link manager  128  is configured to establish and maintain a wireless communication link with portable electronic device  104  via wireless power/communication link transceiver  124  for the purpose of obtaining payment information and other information there from. Such other information may include, for example, device-specific parameters associated with portable electronic device  104  such as a maximum safe power that may be transferred to portable electronic device  104 . Such other information may also include, for example, state information associated with portable electronic device  104  such an amount of power currently consumed or needed by portable electronic device  104 . 
         [0045]    Communication link manager  128  is thus configured to use inductive link  106  for the wireless communication of data. Depending upon the implementation, communication link manager  128  may be configured to carry out the wireless communication of data in accordance with any standard or proprietary induction-based data communication protocol. For example, communication link manager  128  may be configured to carry out the wireless communication of data in accordance with an NFC protocol as described in the Background Section above, although this example is not intended to be limiting and other standard or proprietary induction-based data communication protocols may be used. 
         [0046]    Communication link manager  128  is further configured to transmit control signals to power link manager  126  to control whether and when power link manager  126  may transfer power wirelessly to portable electronic device  104 . Communication link manager  128  can thus ensure that power is transferred to portable electronic device  104  only after requisite payment information has been received from portable electronic device  104 . Communication link manager  128  can also control power link manager  126  to ensure that power is delivered to portable electronic device  104  in a manner that takes into account certain device-specific parameters such as a maximum safe power that may be transferred to portable electronic device  104  or state information such as an amount of power currently consumed or needed by portable electronic device  104 . 
         [0047]    Portable electronic device  104  within power transfer system  100  will now be described. As shown in  FIG. 1 , portable electronic device  104  includes a battery recharging unit  144  connected to wireless power/communication link transceiver  146 . Wireless power/communication link transceiver  146  is configured to transfer wireless power received over inductive link  106  to battery recharging unit  144 , which is configured to use such power to recharge a battery  142  connected thereto. Battery recharging unit  144  is also connected to a load  154  associated with portable electronic device  104 , which can be powered by battery  142  in a well-known manner. 
         [0048]    Portable electronic device  104  further includes a power link monitor  148  connected between wireless power/communication link transceiver  146  and battery recharging unit  144 . Power link monitor  148  may be configured to monitor an amount of power that is wirelessly received via inductive link  106  and to provide this information to a communication link manager  150 . Power link monitor  148  may provide other state information to communication link manager  150  including, for example, a current state of battery  142 . 
         [0049]    Communication link manager  150  is connected both to power link monitor  148  and to wireless power/communication link transceiver  146 . Communication link manager  150  is configured to establish and maintain a wireless communication link with charging station  102  via wireless power/communication link transceiver  146  for the purpose of providing payment information and other information thereto. As noted above, such other information may include, for example, device-specific parameters associated with portable electronic device  104 , such as a maximum safe power that may be transferred to portable electronic device  104 , or state information associated with portable electronic device  104  such an amount of power currently consumed or needed by portable electronic device  104 . This state information may be based on or derived from state information provided by power link monitor  148 . 
         [0050]    Communication link manager  150  is thus configured to use inductive link  106  for the wireless communication of data. Depending upon the implementation, communication link manager  150  may be configured to carry out the wireless communication of data in accordance with any standard or proprietary induction-based data communication protocol. For example, communication link manager  150  may be configured to carry out the wireless communication of data in accordance with an NFC protocol as described in the Background Section above, although this example is not intended to be limiting and other standard or proprietary induction-based data communication protocols may be used. 
         [0051]      FIG. 2  depicts a flowchart  200  of a method for wirelessly transferring power from a charging station to a portable electronic device in accordance with an embodiment of the present invention. The method of flowchart  200  will now be described in reference to certain elements of example wireless transfer system  100  as described above in reference to  FIG. 1 . However, the method is not limited to that implementation. 
         [0052]    As shown in  FIG. 2 , the method of flowchart  200  begins at step  202  in which power link manager  126  of charging station  102  establishes a wireless power link with portable electronic device  104 . Power link manager  126  performs this function by allowing power to flow from power source  122  to wireless power/communication link transceiver  124 , which has the effect of creating inductive link  106  between wireless power/communication link transceiver  124  of charging station  102  and wireless power/communication link transceiver  146  of portable electronic device  104 . As discussed above, depending upon the implementation of wireless power/communication link transceiver  124  and wireless power/communication link transceiver  146 , inductive link  106  may be created for example based on the principles of inductive coupling or resonant inductive coupling. 
         [0053]    At step  204 , communication link manager  128  of charging station  102  establishes a wireless communication link with portable electronic device  104 . Communication link manager  128  performs this function by transmitting and/or receiving signals via wireless power/communication link transceiver  124  to/from wireless power/communication link transceiver  146  associated with portable electronic device  104 . The wireless communication link is thus established via inductive link  106 . As discussed above, the wireless communication link may be established in accordance with any standard or proprietary inductance-based data communication protocol. 
         [0054]    At step  206 , communication link manager  128  of charging station  102  receives payment information from portable electronic device  104  via the wireless communication link. As will be appreciated by persons skilled in the relevant art(s), the type of payment information that is received during step  206  may vary depending on the manner in which the wireless power transfer service is to be paid for by the user of portable electronic device  104 . 
         [0055]    For example, if the user will pay for the wireless power transfer through the subsequent billing of a credit card account, checking account, or some other account from which funds may be transferred, then the payment information may include a unique account identifier, such as an account number. Alternatively, if the charge to the user will be added to a list of additional charges due from the user (e.g., the charge is to be added to a hotel bill for the user), then the payment information may include a unique identifier of the user. 
         [0056]    Furthermore, if the user has already paid for the wireless power transfer, then the payment information may include an electronic token indicating that such payment has occurred. Alternatively, if the user has purchased prepaid credits towards the wireless power transfer, then the payment information may include an electronic funds amount that is currently available to the user/owner for obtaining the service. The electronic funds amount may be stored on portable electronic device  104 , or a card inserted or attached to portable electronic device  104 . 
         [0057]    The foregoing description of the types of payment information that may be received during step  206  are provided by way of example only and are not intended to limit the present invention. Persons skilled in the relevant art(s) will readily appreciate that other types of payment information may be received during step  206  other than or in addition to those types described above. 
         [0058]    After the payment information has been received by communication link manager  128  during step  206 , communication link manager  128  sends one or more control signals to power link manager  126  and, responsive to receiving the control signal(s), power link manager  126  allows power to be transferred to portable electronic device  104  over the wireless power link. This is generally shown at step  208 . 
         [0059]    In an embodiment, communication link manager  128  validates and/or processes the payment information prior to sending the control signal(s) to power link manager  126 . In another embodiment, communication link manager  128  transmits the payment information to an external entity for validation and/or processing prior to sending the control signal(s) to power link manager  126 . For example, communication link manager  128  may provide the payment information to a network interface within charging station  102  (not shown in  FIG. 1 ) for wired or wireless communication to a network entity, such as a server, for processing and/or validation. 
         [0060]    In a further implementation of the foregoing method, power link manager  126  monitors or meters the amount of power wirelessly transferred to portable electronic device  104  via the wireless power link. The monitored amount can then be used to charge the user of portable electronic device  104  based on the amount of power transferred. In one embodiment, the monitored amount is transmitted to an external entity so that the user of portable electronic device  104  may be charged based on the monitored amount. The external entity may be, for example, a remote network entity, such as a server, or may be portable electronic device  104 . 
         [0061]    In the foregoing method of flowchart  200 , the establishment of the wireless power link in step  202  may occur before, contemporaneously with, or after the establishment of the wireless communication link in step  204  depending upon the implementation. Furthermore, the establishment of the wireless power link may occur responsive to the establishment of the wireless communication link or vice versa. With respect to the establishment of the wireless communication link, either charging station  102  or portable electronic device  104  may act as the initiator depending upon the implementation. 
         [0062]      FIG. 3  depicts a flowchart  300  of a method for wirelessly receiving power from a charging station by a portable electronic device in accordance with an embodiment of the present invention. In contrast to the steps of flowchart  200 , which are performed by a charging station, the steps of flowchart  300  are performed by a portable electronic device that is configured to interact with a charging station. Thus, the method of flowchart  300  may be thought of as a counterpart method to the method of flowchart  200 . 
         [0063]    The method of flowchart  300  will now be described in reference to certain elements of example wireless transfer system  100  as described above in reference to  FIG. 1 . However, the method is not limited to that implementation. 
         [0064]    As shown in  FIG. 3 , the method of flowchart  300  begins at step  302  in which a wireless power link is established between wireless power/communication link transceiver  146  of portable electronic device  104  and wireless power/communication link transceiver  124  of charging station  102 . The manner in which such a wireless power link is established was discussed above in reference to step  202  of flowchart  200 . 
         [0065]    At step  304 , communication link manager  150  of portable electronic device  104  establishes a wireless communication link with charging station  102 . Communication link manager  150  performs this function by transmitting and/or receiving signals via wireless power/communication link transceiver  146  to/from wireless power/communication link transceiver  124  associated with charging station  102 . The wireless communication link is thus established via inductive link  106 . As discussed above, the wireless communication link may be established in accordance with any standard or proprietary inductance-based data communication protocol. 
         [0066]    At step  306 , communication link manager  150  of portable electronic device  104  transmits payment information to charging station  102  via the wireless communication link. As will be appreciated by persons skilled in the relevant art(s), the type of payment information that is transmitted during step  306  may vary depending on the manner in which the wireless power transfer service is to be paid for by the user of portable electronic device  104 . Examples of various types of payment information were described above in reference to step  206  of flowchart  200 . 
         [0067]    Responsive to the receipt of the payment information by charging station  102 , charging station  102  transfers power to portable electronic device  104  over the wireless power link. The transferred power is received by wireless power/communication link transceiver  146  and applied to battery recharging unit  144 . This is generally shown at step  308 . 
         [0068]    In the foregoing method of flowchart  300 , the establishment of the wireless power link in step  302  may occur before, contemporaneously with, or after the establishment of the wireless communication link in step  304  depending upon the implementation. Furthermore, the establishment of the wireless power link may occur responsive to the establishment of the wireless communication link or vice versa. With respect to the establishment of the wireless communication link, either charging station  102  or portable electronic device  104  may act as the initiator depending upon the implementation. 
         [0069]      FIG. 4  depicts a flowchart  400  of an additional method for wirelessly transferring power from a charging station to a portable electronic device in accordance with an embodiment of the present invention. The method of flowchart  400  will now be described in reference to certain elements of example wireless transfer system  100  as described above in reference to  FIG. 1 . However, the method is not limited to that implementation. 
         [0070]    As shown in  FIG. 4 , the method of flowchart  400  begins at step  402  in which power link manager  126  of charging station  102  establishes a wireless power link with portable electronic device  104 . Power link manager  126  performs this function by allowing power to flow from power source  122  to wireless power/communication link transceiver  124 , which has the effect of creating inductive link  106  between wireless power/communication link transceiver  124  of charging station  102  and wireless power/communication link transceiver  146  of portable electronic device  104 . As discussed above, depending upon the implementation of wireless power/communication link transceiver  124  and wireless power/communication link transceiver  146 , inductive link  106  may be created based on the principles of inductive coupling or resonant inductive coupling for example. 
         [0071]    At step  404 , communication link manager  128  of charging station  102  establishes a wireless communication link with portable electronic device  104 . Communication link manager  128  performs this function by transmitting and/or receiving signals via wireless power/communication link transceiver  124  to/from wireless power/communication link transceiver  146  associated with portable electronic device  104 . The wireless communication link is thus established via inductive link  106 . As discussed above, the wireless communication link may be established in accordance with any standard or proprietary inductance-based data communication protocol. 
         [0072]    At step  406 , communication link manager  128  of charging station  102  receives parameters and/or state information from portable electronic device  104  via the wireless communication link. The parameters may include, for example, a maximum safe power that may be transmitted to portable electronic device  104 . The state information may include, for example, an amount of power currently consumed or needed by portable electronic device  104 . 
         [0073]    After receiving the parameters and/or state information, communication link manager  128  sends one or more control signals to power link manager  126  and, responsive to receiving the control signal(s), power link manager  128  transfers power to portable electronic device  104  over the wireless power link in a manner that takes into account the received parameters and/or state information. This is generally shown at step  408 . 
         [0074]    In one embodiment, controlling the power transfer in accordance with received parameters includes controlling the wireless power link to ensure that the amount of power transferred over the link does not exceed a maximum safe power that may be transmitted to portable electronic device  104 . In another embodiment, controlling the power transfer in accordance with received state information includes controlling the wireless power link to ensure that the amount of power that is transferred over the link is sufficient to recharge portable electronic device  104  or does not exceed an amount of power that is sufficient to recharge portable electronic device  104 . 
         [0075]    In the foregoing method of flowchart  400 , the establishment of the wireless power link in step  402  may occur before, contemporaneously with, or after the establishment of the wireless communication link in step  404  depending upon the implementation. Furthermore, the establishment of the wireless power link may occur responsive to the establishment of the wireless communication link or vice versa. With respect to the establishment of the wireless communication link, either charging station  102  or portable electronic device  104  may act as the initiator depending upon the implementation. 
         [0076]      FIG. 5  depicts a flowchart  500  of a method for wirelessly receiving power from a charging station by a portable electronic device in accordance with an embodiment of the present invention. In contrast to the steps of flowchart  400 , which are performed by a charging station, the steps of flowchart  500  are performed by a portable electronic device that is configured to interact with a charging station. Thus, the method of flowchart  500  may be thought of as a counterpart method to the method of flowchart  400 . 
         [0077]    The method of flowchart  500  will now be described in reference to certain elements of example wireless transfer system  100  as described above in reference to  FIG. 1 . However, the method is not limited to that implementation. 
         [0078]    As shown in  FIG. 5 , the method of flowchart  500  begins at step  502  in which a wireless power link is established between wireless power/communication link transceiver  146  of portable electronic device  104  and wireless power/communication link transceiver  124  of charging station  102 . The manner in which such a wireless power link is established was discussed above in reference to step  402  of flowchart  400 . 
         [0079]    At step  504 , communication link manager  150  of portable electronic device  104  establishes a wireless communication link with charging station  102 . Communication link manager  150  performs this function by transmitting and/or receiving signals via wireless power/communication link transceiver  146  to/from wireless power/communication link transceiver  124  associated with charging station  102 . The wireless communication link is thus established via inductive link  106 . As discussed above, the wireless communication link may be established in accordance with any standard or proprietary inductance-based data communication protocol. 
         [0080]    At step  506 , communication link manager  150  of portable electronic device  104  transmits parameters and/or state information to charging station  102  via the wireless communication link. As noted above, the parameters may include, for example, a maximum safe power that may be transmitted to portable electronic device  104  and the state information may include, for example, an amount of power currently consumed or needed by portable electronic device  104 . 
         [0081]    In an embodiment, communication link manager  150  generates or derives the state information from information collected by power link monitor  148 . For example, power link monitor  148  may monitor the wireless power link to determine an amount of power transferred over the link. This amount of power may then be reported as state information to charging station  102  over the wireless communication link. Additionally, power link monitor  148  may provide other state information to communication link manager  150  including, for example, a current state of battery  142 . 
         [0082]    Responsive to the receipt of the parameters and/or state information by charging station  102 , charging station  102  transfers power to portable electronic device  104  over the wireless power link, wherein the manner in which power is transferred is controlled in accordance with the parameters and/or state information. The transferred power is received by wireless power/communication link transceiver  146  and applied to battery recharging unit  144 . This is generally shown at step  508 . 
         [0083]    In the foregoing method of flowchart  500 , the establishment of the wireless power link in step  502  may occur before, contemporaneously with, or after the establishment of the wireless communication link in step  504  depending upon the implementation. Furthermore, the establishment of the wireless power link may occur responsive to the establishment of the wireless communication link or vice versa. With respect to the establishment of the wireless communication link, either charging station  102  or portable electronic device  104  may act as the initiator depending upon the implementation. 
       B. Alternative Wireless Power Transfer System Implementations 
       [0084]    Alternative implementations of wireless power transfer system  100  will now be described. Each of the alternative implementations is also capable of wirelessly transferring/receiving power in accordance with the methods of flowcharts  200 ,  300 ,  400  and  500  as described above in reference to  FIG. 2 ,  FIG. 3 ,  FIG. 4  and  FIG. 5 , respectively. 
         [0085]    For example,  FIG. 6  is a block diagram of a wireless power transfer system  600  that includes similar elements to those described in reference to  FIG. 1  except that the wireless power link between the charging station and the portable electronic device is implemented using a wireless power transmitter and receiver while the wireless communication link between the charging station and the portable electronic device is implemented using a separate pair of communication link transceivers. 
         [0086]    As shown in  FIG. 6 , wireless power transfer system  600  includes a charging station  602  and a portable electronic device  604 . With the exception of certain elements discussed below, the elements of charging station  602  are configured to function in a similar manner to like-named elements of charging station  102  of  FIG. 1 . Likewise, with the exception of certain elements discussed below, the elements of portable electronic device  604  are configured to function in a similar manner to like-named elements of portable electronic device  104  of  FIG. 1 . 
         [0087]    Charging station  602  includes a wireless power transmitter  624  and portable electronic device  604  includes a wireless power receiver  646 . Wireless power transmitter  624  is configured to operate under the control of power link manager  626  to wirelessly transfer power supplied by power source  622  to wireless power receiver  646  associated with portable electronic device  604  via an inductive link  606 . The wireless power transfer may be carried out over inductive link  606  in accordance with the well-known principles of inductive coupling or resonant inductive coupling as discussed in the Background Section above. The manner in which wireless power transmitter  624  and wireless power receiver  646  are implemented will depend on the type of inductive coupling used. A variety of transmitter and receiver designs based on inductive coupling and resonant inductive coupling are available in the art and thus need not be described herein. 
         [0088]    Charging station  602  further includes a communication link transceiver  630  and portable electronic device  604  further includes a communication link transceiver  652 . In the embodiment shown in  FIG. 6 , communication link transceivers  630  and  652  are used to establish and maintain a wireless communication link  608  between charging station  602  and portable electronic device  604  that is separate from inductive link  606 . Wireless communication link  608  is established for the purpose of transferring payment information and/or device-specific parameters or state information from portable electronic device  604  to charging station  602 . Charging station  602  may then use such information in a like manner to that described above with respect to charging station  102  of  FIG. 1 . 
         [0089]    As will be appreciated by persons skilled in the relevant art(s), the manner in which communication link transceivers  630  and  652  are implemented will depend on the type of wireless communication link to be established there between. In accordance with one embodiment of the present invention, wireless communication link  608  may be established using NFC technology as described above in the Background Section. Alternatively, wireless communication link  608  may be established in accordance with certain RF-based short-range communication technologies such as Bluetooth™, as described in the various standards developed and licensed by the Bluetooth™ Special Interest Group, or technologies such as ZigBee® that are based on the IEEE 802.15.4 standard for wireless personal area networks (specifications describing ZigBee are publically available from the ZigBee® Alliance). Still further, wireless communication link  608  may be established in accordance with other RF-based communication technologies such as any of the well-known IEEE 802.11 protocols. However, these examples are not intended to be limiting and wireless communication link  608  between charging station  602  and portable electronic device  604  may be established using a variety of other standard or propriety communication protocols. 
         [0090]      FIG. 7  is a block diagram of a wireless power transfer system  700  that includes similar elements to those described in reference to  FIG. 6  except that the wireless communication link between the portable electronic device and the charging station is unidirectional rather than bidirectional. 
         [0091]    As shown in  FIG. 7 , wireless power transfer system  700  includes a charging station  702  and a portable electronic device  704 . With the exception of certain elements discussed below, the elements of charging station  702  are configured to function in a similar manner to like-named elements of charging station  602  of  FIG. 6 . Likewise, with the exception of certain elements discussed below, the elements of portable electronic device  704  are configured to function in a similar manner to like-named elements of portable electronic device  604  of  FIG. 6 . 
         [0092]    As further shown in  FIG. 7 , portable electronic device  704  includes a communication link transmitter  752  and charging station  702  includes a communication link receiver  730 . Communication link manager  750  within portable electronic device  704  is configured to establish a unidirectional wireless communication link  708  with charging station  702  by transmitting signals via communication link transmitter  752  to communication link receiver  730 . This unidirectional wireless communication link may then be used to transmit payment information and/or device-specific parameters or state information from portable electronic device  704  to charging station  702 . Charging station  702  may then use such information in a like manner to that described above with respect to charging station  102  of  FIG. 1 . 
         [0093]      FIG. 8  is a block diagram of a wireless power transfer system  800  that includes similar elements to those described in reference to  FIG. 6  except that the charging station includes a plurality of different communication link transceivers to facilitate the establishment of wireless communication links with a plurality of different types of portable electronic devices. 
         [0094]    As shown in  FIG. 8 , wireless power transfer system  800  includes a charging station  802  and a portable electronic device  804 . With the exception of certain elements discussed below, the elements of charging station  802  are configured to function in a similar manner to like-named elements of charging station  602  of  FIG. 6 . Likewise, with the exception of certain elements discussed below, the elements of portable electronic device  804  are configured to function in a similar manner to like-named elements of portable electronic device  604  of  FIG. 6 . 
         [0095]    As further shown in  FIG. 8 , charging station  802  includes a plurality of communication link transceivers connected to communication link manager  828 . The plurality of communication link transceivers includes a first communication link transceiver  830 , a second communication link transceiver  832 , and so on, up to an n th  communication link transceiver  834 . Each of the communication link transceivers is configured for wireless communication in accordance with a different wireless protocol. For example, first communication link transceiver  830  may be configured for communication in accordance with NFC, second communication link transceiver  832  may be configured for communication in accordance with Bluetooth™, and n th  communication link transceiver  834  may be configured for communication in accordance with one of the IEEE 802.11 standards. This advantageously enables charging station  802  to receive payment information and device-specific parameters and/or state information from a plurality of different device types to facilitate the wireless transfer of power to such devices. 
       C. Conclusion 
       [0096]    While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be understood by those skilled in the relevant art(s) that various changes in form and details may be made to the embodiments of the present invention described herein without departing from the spirit and scope of the invention as defined in the appended claims. Accordingly, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.