Passive rf devices that communicate using a wireless network protocol

Abstract

Passive RF devices are disclosed that communicate using a wireless network protocol. The device includes an antenna operable to receive a radio frequency (RF) signal from a RF source that transmits the RF signal based on a wireless network protocol. The device further includes circuitry operable to derive power from the RF signal. With the power derived from the RF signal, the circuitry is further operable to read data from a memory, to encode the data based on the wireless network protocol, and to modulate the RF signal to include the encoded data. The antenna is further operable to transmit the modulated RF signal based on the wireless network protocol for reception by the RF source or another passive RF device.

We claim: 
     
         1 . A Radio Frequency Identification (RFID) system comprising:
 an active Radio Frequency (RF) device operable to transmit an RF signal based on a wireless network protocol;   a first passive RF device attached to a power cord of an electrical device, the first passive RF device operable to store an identifier (ID) for the electrical device, to derive power from the RF signal, and to transmit the ID for the electrical device to the active RF device based on the wireless network protocol; and   a second passive RF device attached to a power strip that receives the power cord for the electrical device, the second passive RF device operable to store an ID for the power strip, to derive power from the RF signal, and to transmit the ID for the power strip to the active RF device based on the wireless network protocol;   the active RF device is further operable to retrieve power usage data for the electrical device from the power strip, and to aggregate the ID for the electrical device, the ID for the power strip, and the power usage data for the electrical device.   
     
     
         2 . The RFID system of  claim 1  further comprising:
 a third passive RF device attached to a wall outlet that electrically connects to the power strip, the third passive RF device operable to store an ID for the wall outlet, to derive power from the RF signal, and to transmit the ID for the wall outlet to the active RF device based on the wireless network protocol. 
 
     
     
         3 . The RFID system of  claim 2  wherein:
 the aggregation further comprises the ID for the wall outlet. 
 
     
     
         4 . The RFID system of  claim 1  further comprising:
 the active RF device is further operable to transmit the aggregated information to a computer using the wireless network protocol. 
 
     
     
         5 . The RFID system of  claim 4  further comprising:
 an application on the computer operable to process the aggregated information to generate a log of the power usage for the electrical device. 
 
     
     
         6 . The RFID system of  claim 1  wherein:
 the wireless network protocol is based on the IEEE 802.15.4 standard. 
 
     
     
         7 . The RFID system of  claim 1  wherein:
 the wireless network protocol is based on the IEEE 802.11 standard. 
 
     
     
         8 . A method comprising:
 transmitting by an active Radio Frequency (RF) device an RF signal based on a wireless network protocol;   storing an identifier (ID) for an electrical device by a first passive RF device attached to a power cord of the electrical device, deriving, by the first passive RF device, power from the RF signal, and transmitting, by the first passive RF device, the ID for the electrical device to the active RF device based on the wireless network protocol;   storing an ID for a power strip by a second passive RF device attached to a power strip that receives the power cord for the electrical device, deriving, by the second passive RF device, power from the RF signal, and transmitting, by the second passive RF device, the ID for the power strip to the active RF device based on the wireless network protocol; and   retrieving, by the active RF device, power usage data for the electrical device from the power strip, and aggregating the ID for the electrical device, the ID for the power strip, and the power usage data for the electrical device.   
     
     
         9 . The method of  claim 8  further comprising:
 storing an ID for the wall outlet by a third passive RF device attached to a wall outlet that electrically connects to the power strip, deriving, by the third passive RF device, power from the RF signal, and transmitting, by the third passive RF device, the ID for the wall outlet to the active RF device based on the wireless network protocol. 
 
     
     
         10 . The method of  claim 9  further comprising:
 including the ID for the wall outlet in the aggregation. 
 
     
     
         11 . The method of  claim 8  further comprising:
 transmitting, with the active RF device, the aggregated information to a computer using the wireless network protocol. 
 
     
     
         12 . The method of  claim 11  further comprising:
 processing, with an application on the computer, the aggregated information to generate a log of the power usage for the electrical device. 
 
     
     
         13 . The method of  claim 8  wherein:
 the wireless network protocol is based on the IEEE 802.15.4 standard. 
 
     
     
         14 . The method of  claim 8  wherein:
 the wireless network protocol is based on the IEEE 802.11 standard. 
 
     
     
         15 . A Radio Frequency Identification (RFID) system comprising:
 an active RF device operable to generate a request, to encode the request based on a wireless network protocol, to modulate a radio frequency (RF) signal to include the encoded request, and to transmit the RF signal to a passive RF device.   
     
     
         16 . The RFID system of  claim 15  wherein:
 the active RF device is operable to receive a response to the request from the passive RF device, to generate an acknowledgement of the response, to encode the acknowledgement based on the wireless network protocol, to modulate the RF signal to include the encoded acknowledgment, and to transmit the RF signal to the passive RF device. 
 
     
     
         17 . The RFID system of  claim 15  wherein:
 the request indicates a file name; and 
 the passive RF device is operable to identify a file stored in memory based on the file name in the request, and to insert the file in a response. 
 
     
     
         18 . The RFID system of  claim 15  wherein:
 the wireless network protocol is based on the IEEE 802.15.4 standard. 
 
     
     
         19 . The RFID system of  claim 15  wherein:
 the wireless network protocol is based on the IEEE 802.11 standard. 
 
     
     
         20 . The RFID system of  claim 15  wherein:
 the request indicates a frequency for data transmittal.