Abstract:
A radio frequency (RF) device for authorizing user access to portions of a computer system. The RF device includes a power supply, processing circuitry that accesses the power supply according to a location of the RF device, and an antenna that transmits communication signals from the processing circuitry to a transponder that is coupled to the computer system. The processing circuitry is configured to operate at a first power level until the communication signals indicate that the location of the RF device is within a first range of the transponder. The processing circuitry is configured to begin operations at a second power level after the RF device is positioned within the first range of the transponder. The processing circuitry is also configured to operate at the second power level until the communication signals indicate that the location of the RF device has moved outside of a second range from the transponder.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to access authentication in a computer system, and more particularly, to optimizing battery life in contactless technology tokens. 
   2. Description of the Related Art 
   Automatic identification procedures have become increasingly popular with improvements in computer technology. Different communication protocols exist to authenticate users that attempt to access computer systems, computer networks, etc. Radio frequency (RF) devices are commonly used to automatically identify a person that desires to access a computer system. However, these RF devices suffer from constant battery drainage because the power is always activated as the RF device constantly broadcasts its authentication signal. Past solutions to the constant battery consumption have included offering an on/off switch on the RF device to control transmissions from the RF device when authentication is not needed and thus conserve battery power of the RF device. Among other things, this solution is cumbersome and fails to optimize the battery power savings with authentication transmissions. 
   Many other problems and disadvantages of the prior art will become apparent to one of ordinary skill in the art when comparing the prior art with the present invention as described herein. 
   BRIEF SUMMARY OF THE INVENTION 
   Various aspects of the present invention are realized with a radio frequency (RF) device for authorizing user access to portions of a computer system. The RF device includes a power supply, processing circuitry that accesses the power supply according to a location of the RF device, and an antenna that transmits communication signals from the processing circuitry to a transponder that is coupled to the computer system. The processing circuitry is configured to operate at a first power level until the communication signals indicate that the location of the RF device is within a first range of the transponder. The processing circuitry is configured to begin operations at a second power level after the RF device is positioned within the first range of the transponder. The processing circuitry is also configured to operate at the second power level until the communication signals indicate that the location of the RF device has moved outside of a second range from the transponder. 
   The RF device may use the communication signals to verify that the RF device is an authorized device prior to activating user access to the portions of the computer system. The RF device may also use the communication signals to verify that the computer system is an authorized computer system for the RF device to activate prior to the RF device operating at the second power level. The processing circuitry of the RF device typically identifies the location of the RF device through communication signals that are received through the antenna on the RF device. The processing circuitry may operates at the first power level when the processing circuitry is unable to identify the location of the RF device. In some embodiments, the computer system is completely inaccessible by a user when the computer system is unable to identify the location of the RF device. Also, the computer system may periodically validate itself to the RF device and the RF device may periodically validate itself to the computer system. The RF device may include a key that is provided to the processing circuitry that the processing circuitry requires for high power transactions. The key for the high power transactions may be modified over time, such as when a particular event occurs, e.g., when a predetermined number of packets have passed a check point. A common distance for the first range is from about five to twenty centimeters, while the second range is commonly from about five to twenty meters. 
   Other aspects of the present invention are realized with a radio frequency (RF) device for authorizing user access to portions of a computer system. The RF device includes a power supply, processing circuitry that accesses the power supply according to a location of the RF device, and an antenna that transmits communication signals from the processing circuitry to a transponder that is coupled to the computer system. The processing circuitry is configured to operate at a first power level until authentication signals verify that the location of the RF device is within a first range of the transponder at which time the processing circuitry begins operations at a second power level. The processing circuitry is configured to operate at the second power level until the location of the RF device is detected to have moved outside of a second range from the transponder. 
   Still other aspects of the present invention are realized through a method for an RF device to conserve power while controlling user access to a computer system having a transponder. The method involves operating the RF device in a low power mode; placing the RF device within ten centimeters of the transponder to initiate RF communications between the RF device and the computer system while the RF device remains in the low power mode; authenticating a valid identity for the RF device; identifying portions of the computer system that a user with the RF device is permitted to access; activating the identified portions of the computer system; and activating a high power state in the RF device that permits the RF device to maintain the activation of the identified portions of the computer system while the RF device remains within 10 meters of the transponder. 
   The method may also include deactivating the high power state in the RF device when the RF communications between the RF device and the computer system cease. It should be noted that prior to activating the high power state in the RF device, the method may include authenticating the computer system as a valid computer system for operations with the RF device. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a block diagram of basic components that are involved in understanding principles of the present invention. 
       FIG. 2  is a flow diagram of a method that demonstrates fundamental power saving techniques when using the components of  FIG. 1 . 
       FIG. 3  is a flow diagram of an exemplary embodiment of a method for conserving power that is consumed by a token that operates according to principles of the present invention. 
       FIG. 4  illustrates an exemplary embodiment of a token that operates with power saving techniques such as found in  FIG. 2 . 
       FIG. 5  is a flow diagram of an exemplary embodiment of a method for conserving power in a token, the method is similar to the method of  FIG. 3 , but includes an authentication loop in addition to the method of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a block diagram of basic components that are involved in understanding principles according to the present invention. A token  102  is a radio frequency (RF) device that communicates with a transponder  104  and processor  106 . Token  102  communication with the processor  106  depends, in part, upon the power state of the token  102 . In one embodiment, the token  102  operates in either a low or a high power state. For example, when the token  102  operates in a low power state, a short range between the token  102  and the transponder  104  is required for communications between the token  102  and the processor  106 . The token  102  operates in a low power state, among other things, to conserve the amount of power that is consumed by the token&#39;s power source (see  FIG. 4 ) when the processor  106  is not activated. The token  102  periodically pulses a short range RF signal to request if the transponder  104  is within communication range. Until the token  102  detects that the transponder  104  is within range, e.g., within approximately five to twenty centimeters, the token  102  remains in the low power state. Of course, five to twenty centimeters is an exemplary range for activation and is used for purpose of understanding principles of the present invention. Those of ordinary skill in the art will understand that the range may be modified according to user needs in a particular embodiment. 
   When the token  102  is within range of the transponder  104 , the processor  106  validates authentication information from the token  102 . If the authentication information is validated, the processor  106  is released for access by a user, preferably the person that is in possession of the token  102 . 
   The token  102  is then placed into a high power state. Although the high power state of the token  102  consumes a greater amount of power than the low power state, the high power state, among other things, offers a greater range for communications between the token  102  and the transponder  104  and thus the processor  106 . The processor  106  periodically checks for the presence of the token  102  and continues to allow access until the token  102  is out of range of the processor  106 . The token  102 , in its low power state, is required to be within a first range (approximately five to ten or twenty centimeters) of the transponder  104  to communicate with the processor  106 . In its high power state, the token  102  may be moved up to a second range (approximately five to ten or twenty meters) from the transponder  104  before the processor  106  is deactivated and access to the processor  106  is denied. Of course, the first and the second ranges of the token  102  varies with the token  102  and processor  106  configurations. As such, the range distances specified above are exemplary only and may be modified accordingly to the needs of a particular embodiment. 
     FIG. 2  is a flow diagram  200  of a method that demonstrates fundamental power saving techniques when using the components of  FIG. 1 . The token  102  is typically in the possession of a person that periodically accesses a computer system such as the processor  106 . When the person is apart from the processor  106  and not accessing the processor  106 , the token  102  is in a low power state. In the low power state, when the token  102  is located more than a predetermined distance, e.g., ten centimeters from the transponder  104 , the token  102  does not communicate with the processor  106 . Because the token  102  is operating in the low power state, its identifying information is not received by the transponder  104 . The method of  FIG. 2  begins with the step  202  of placing the token  102 , in its low power state, near the transponder  104 . Although the token  102  is operating in the low power state, in the following step  204 , the token  102  detects an activating signal from the processor  106 . Once the token  102  detects the activating signal from the processor  106 , the token  102  activates its high powered circuitry  206  which allows the token  102  to travel up to approximately five to twenty meters away from the transponder  104  prior to losing communications with the processor  106 . Of course, the five to twenty meter range is exemplary only and, upon viewing the present disclosure, will be understood by those of ordinary skill in the art to be a flexible range. When communications with the processor  106  are lost, the processor  106  is deactivated for lack of a validating token and the token  102  is returned to its low power state to conserve battery/power supply power. 
     FIG. 3  is a flow diagram  300  of an exemplary embodiment of a method for conserving token power in a token that operates according to principles of the present invention. In the embodiment of  FIG. 3 , in the first step  302 , the token  102  is placed near the transponder  104 . In the next step  304 , the token  102  detects the processor  106  and, in turn, the token  102  is set to a high power state with a variable, “Timeout,” being set to equal a loop count value  306 . The loop count value is the number of invalid messages that the processor  106  will tolerate before instructing the token  102  to drop back into its low power state. 
   Specifically, after the token  102  has its high power state activated and ‘Timeout’ is set to equal the loop count, the token  102  enters a power loop  308 . In the next step  310 , if ‘Timeout’ is found to be zero, then the token  102  returns to the low power state  312 , otherwise, the token  102  sends a message to the processor  314 . In the next step  316 , if the processor  106  indicates that the message was not received by the processor  106 , the token  102  returns to the low power state, otherwise, the message is checked for validity  318 . An invalid message causes Timeout to be decremented by one  320  and the flow diagram  300  returns to the beginning of the power loop  308  for another loop iteration. On the other hand, a valid message from the token  102  leads to a delay  322  and a reset of the ‘Timeout’ variable. After the delay  322 , the power loop completes  324  and returns for another iteration. 
     FIG. 4  illustrates an exemplary embodiment of a token  400  that operates with power saving techniques such as found in the flow diagram  200 . The token  400  includes an antenna  402  that is electrically coupled to a receiver logic latch  404 . The receiver logic latch  404  is electrically coupled to wired communication hardware  406  such as an RFID (Radio Frequency Identifier)  406  that is made up of a power supply  408  and token circuitry  410 . The token circuitry  410  controls the amount of power that is used by the power supply  408  based on the distance that the token  400  is positioned from a transponder such as the transponder  104 . 
   For example, the token  400  operates in a low power state until the token  400  is brought within approximately ten centimeters of a transponder/processor pair that is programmed to recognize communication signals from the token  400 . Multiple token  400  operations may occur at this point. For example, the token  400  may automatically move to a high power state for further communications with the processor. In another embodiment, the token  400  may request the processor to validate itself prior to the token  400  moving into its high powered state. In yet another embodiment, the token  400  may wait until the processor has confirmed that the token  400  is a valid token prior to activating its high powered state. Regardless, when the token  400  recognizes that it may communicate with the processor in its high powered state, the token  400  changes into its high powered state and operates according to the programming in the token  400  and processor. 
     FIG. 5  is a flow diagram of an exemplary embodiment of a method  500  for conserving power in a token. The method  500  is similar to the method  300 , but includes an authentication loop in addition to the flow diagram (method)  300 . Similar to the method  300 , initially, a token is placed near a transponder  502 . The token is in a low power state and must be placed approximately ten centimeters from the transponder in order to communicate with the processor. Once the token detects the processor  504 , a “Timeout” variable is set to equal a loop count  506  and an initial authentication loop is entered prior to raising the token to a high power state. In the first step  508 , the Timeout variable value is checked, if it is not zero, a check is made for whether the token has received a message  510 . If a message has been received and a valid message  512  indication from the processor indicates that the message is not valid, Timeout is decremented  514  and the loop returns to checking the value of Timeout  508 . If Timeout has reached zero, the loop is exited  516 , i.e., the token is not raised to a higher power state and the method  500  begins again. Alternatively, if Timeout has not reached zero, but no message is received  510 , then the loop is also exited  516 . 
   Once a valid message  512  is indicated, the Timeout variable is reset to equal the loop count  518  and the power loop is entered  520  by raising the token to its high power state and activating the processor. Timeout is checked for a zero value  522 , if not zero, then a check is made for whether a message has been received  524 . If a message has been received, a check is made on whether the message is valid  526 . Similar to the first authentication loop, if the message is not found to be valid, Timeout is decremented  528  and the power loop  520  is reentered. If Timeout has reached zero, the loop is exited, the processor deactivated, and the token returned to low power mode  530 . Also, if Timeout does not equal zero but no message is received  524 , the processor is deactivated and the token returns to low power mode  530 . However, if a valid message is detected  526 , then the token sends a message to the processor  532  and a delay occurs with Timeout being reset  534 . The delay  534  further assists in token power conservation because the token circuitry temporarily ceases to check all token variables while leaving the processor activated. After the delay  534 , the high power loop ends  536  and another iteration of the power loop begins. 
   The above-listed sections and included information are not exhaustive and are only exemplary for contactless technology such as a token/processor combination herein described. The particular sections and included information in a particular embodiment may depend upon the particular implementation and the included devices and resources. Although a system and method according to the present invention has been described in connection with the preferred embodiment, it is not intended to be limited to the specific form set forth herein, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents, as can be reasonably included within the spirit and scope of the invention as defined by the appended claims.