Method and Apparatus for Power Management for a Radio Frequency Identification System

Abstract

A method and device of power management for a networked radio frequency identification (“RFID”) system are disclosed. The described power management methods reduce the power consumption of battery-operated RFD) readers and RFD tags. These power conservation methods increase the RFID system's hours of operation and decrease the cost by allowing the RFID readers and tags to function for a longer period of time before requiring charging or replacement of their batteries.

1 - 14 . (canceled) 
     
     
         15 . A method for transmitting information relating to radio frequency identification (“RFID”) in an RFID reader, comprising:
 obtaining location information from a global positioning system (“GPS”); 
 calculating a current location of said RFID reader according to said location information; 
 retrieving a plurality of active RF reading zones relating to said current location of said RFID reader from a storage location of said RFID reader; 
 determining whether said current location of said RFID reader is within said at least one zone of said plurality of active RF reading zones; and 
 switching at least a portion of components of said RFID reader into a sleep state to conserve power if said current location of said RFID reader is outside of any of said plurality of active RF reading zones. 
 
     
     
         16 . The method of  claim 15 , further comprising:
 activating at least a portion of components of said RFID reader from said sleep state to an active state if said current location of said RFID reader is within said at least one of said plurality of active RF reading zones.   
     
     
         17 . The method of  claim 15 , wherein said determining whether said current location of said RFID reader is within at least one zone of said plurality of active RF reading zones further includes:
 identifying power efficient reading zones from said plurality of active RF reading zones according to said location information; and   comparing said current location of said RFID reader with at least one of said power efficient reading zones.   
     
     
         18 . The method of  claim 15 , wherein said determining whether said current location of said RFID reader is within at least one active of said RF reading zone further includes identifying a reading zone with minimal interference in response to said location information. 
     
     
         19 - 27 . (canceled) 
     
     
         28 . A method for transmitting information relating to radio frequency identification (“RFID”) in an RFID system, comprising:
 identifying a first tag to be read; 
 transmitting a first transmission power to read said first tag; 
 transmitting a second transmission power which is higher frequency than said first transmission power to read said first tag if said first transmission power fails to read said first tag; and 
 storing said second transmission power together with an identification of said first tag in a memory unit of an RFID reader for subsequent reads if said second transmission power reads said first tag correctly. 
 
     
     
         29 . The method of  claim 28 , further comprising:
 identifying a second tag to be read;   transmitting a third transmission power to read said second tag;   transmitting a fourth transmission power which is higher than said third transmission power to read said second tag if said third transmission power fails to read said second tag; and   storing said fourth transmission power together with an identification of said second tag of said memory unit in said RFID reader for subsequent reads if said fourth transmission power reads said second tag correctly   
     
     
         30 . The method of  claim 28 , further comprising:
 adjusting the electronic beam-offset and beam-width angles to focus the beam energy more directly on a targeted tag;   storing said beam-offset angle and beam-width angle together with an identification of said tag.   
     
     
         31 - 46 . (canceled) 
     
     
         47 . A method of controlling power consumption of a radio frequency identification (“RFID”) system by an RFID application, The RFID system comprising an RFID reader communicatively coupled to a plurality of tags, the RFID reader comprising a battery, the plurality of tags comprising a set of ultra high frequency (UHF) tags and a set of low frequency (LF) tags, the RFID application capable of utilizing data from either UHF tags or LF tags, the method comprising:
 determining a battery level of the RFID reader; 
 when the battery level is below a predetermined threshold, reading data from the active LF tags and placing the UHF tags into a sleep state; 
 when the battery level is not below the predetermined threshold, reading data from the passive UHF tags and placing the LF tags into a sleep state; and 
 sending the data read from the tags to the RFID application. 
 
     
     
         48 . The method of  claim 47 , wherein the UHF tags are passive tags without an inter power source, wherein the LF tags are active tags comprising an internal power source. 
     
     
         49 . The method of  claim 47 , wherein a set of tags in the plurality of tags are active tags incorporated in an electronic device to prolog prolong a battery lifetime of the active tags. 
     
     
         50 . The method of  claim 49 , wherein the electronic device is one of a cellular phone, a personal digital assistant (PDA), a laptop, a digital camera, and a wireless game console. 
     
     
         51 . The method of  claim 50  further comprising using compact data structure on each tag in the plurality of tags to (i) reduce a power required to interrogate each tags by the RFID reader and (ii) to send data read from each tag to an access point communicatively coupled to the RFID reader. 
     
     
         52 . The method of  claim 50  further comprising adjusting a clock frequency of the RFID reader based on an amount of RFID reader activity. 
     
     
         53 . The method of  claim 50  further comprising configuring the active tags to enter a low power state at regular time intervals. 
     
     
         54 . The method of  claim 50  further comprising:
 determining whether each tag in the set of active tags has a low battery level; and 
 placing an active tag into a sleep state more often when the active tag has a low battery level than when the active tag does not have a low battery level.