Abstract: Tags, wireless communication systems, tag communication methods, and wireless communications methods are described. In one aspect, a tag includes a plurality of antennas configured to receive a plurality of first wireless communication signals comprising data from a reader, a plurality of rectifying circuits coupled with. respective individual ones of the antennas and configured to provide rectified signals corresponding to the first wireless communication signals, wherein the rectified signals are combined to produce a composite signal, an adaptive reference circuit configured to vary a reference signal responsive to the composite signal, a comparator coupled with the adaptive reference circuit and the rectifying circuits and configured to compare the composite signal with respect to the reference signal and to output the data responsive to the comparison, and processing circuitry configured to receive the data from the comparator and to process the data.

Abstract: Wireless communications systems, radio frequency identification devices, wireless communications methods, and radio frequency identification device communications methods are described. In one aspect, a wireless communications system includes a reader configured to output a plurality of wireless signals including different modulation frequencies and to receive a plurality of second wireless signals, a plurality of communication devices configured to receive the first wireless signals and to output the second wireless signals using backscatter modulation and wherein the communication devices are individually configured to respond to one of the first wireless signals having a first modulation frequency at a first moment in time and to respond to one of the first wireless signals having a second modulation frequency different than the first modulation frequency at a second moment in time.

Abstract: Radio frequency identification devices, backscatter communication device wake-up methods, communication device wake-up methods and a radio frequency identification device wake-up method are described.

Abstract: A method of rapidly identifying RFID tags in an RFID system including a reader and a plurality of RFID tags, the tags having respective IDs formed of a plurality of bit locations, the method comprising determining in the reader which bit locations do not add to the uniqueness of the IDs of the tags; and ignoring data in bit locations that do not add to the uniqueness of the IDs of the tags. An RFID system comprising a plurality of RFID tags, the tags having respective IDs formed of a plurality of bit locations; and an RFID reader configured to communicate with the RFID tags, the reader being configured to determine which bit locations do not add to the uniqueness of the IDs of the tags, and to ignore data in bit locations that do not add to the uniqueness of the IDs of the tags.

Abstract: An RFID system comprises an RFID reader configured to issue an RF command requesting that RF tags identify themselves, and to issue timing information defining a plurality of timeslots; and a plurality of RF tags in selective communication with the reader, the RF tags having respective IDs, respective tags being configured to randomly select a timeslot in which to reply to the RF command, and to issue an RF reply in response to the RF command in the randomly selected timeslot, the RF reply including a frequency pattern to assist in identifying the tag but not the tag's entire ID, different tags having different frequency patterns.

Abstract: An RF tag system, comprising an RF reader configured to issue a plurality of different RF commands and to provide a continuous RF illumination field, and a plurality of RF tags respectively including a permanent identification; wherein the plurality of RF tags are configured to respond to a certain RF command from the RF reader by transmitting their respective identifications by way of backscatter modulation of the RF illumination field, and wherein the RF tags are further configured to perform the responding by way of respective independently selected random radio frequencies and timeslots from respective pre-defined ranges of radio frequencies and timeslots.

Abstract: Wireless communication systems, radio frequency identification devices, methods of enhancing a communications range of a radio frequency identification device, and wireless communication methods are described.

Abstract: A method of securing communications in an RFID system including a reader and an RF tag having a memory configured to store information comprises sending, from the reader, a message to the tag; the tag, in response to the message, generating a challenge value and sending the challenge value to the reader; in any order: the reader performing a mathematical operation on the challenge value based upon a key value to generate a challenge reply and sending the challenge reply to the tag and the tag independently computing a challenge response based on the key value and mathematical operation; the tag comparing the challenge response computed by the tag with the challenge reply sent by the reader; and the tag authenticating the reader if the challenge response matches the challenge reply. An RFID system including an RFID tag and a reader are configured to perform the above steps.

Abstract: Radio frequency identification devices, backscatter communication device wake-up methods, communication device wake-up methods and a radio frequency identification device wake-up method are described.

Abstract: An RF tag system, comprising an RF reader configured to issue a plurality of different RF commands and to provide a continuous RF illumination field, and a plurality of RF tags respectively including a permanent identification; wherein the plurality of RF tags are configured to respond to a certain RF command from the RF reader by transmitting their respective identifications by way of backscatter modulation of the RF illumination field, and wherein the RF tags are further configured to perform the responding by way of respective independently selected random radio frequencies and timeslots from respective pre-defined ranges of radio frequencies and timeslots.

Abstract: Tags, wireless communication systems, tag communication methods, and wireless communications methods are described. In one aspect, a tag includes a plurality of antennas configured to receive a plurality of first wireless communication signals comprising data from a reader, a plurality of rectifying circuits coupled with. respective individual ones of the antennas and configured to provide rectified signals corresponding to the first wireless communication signals, wherein the rectified signals are combined to produce a composite signal, an adaptive reference circuit configured to vary a reference signal responsive to the composite signal, a comparator coupled with the adaptive reference circuit and the rectifying circuits and configured to compare the composite signal with respect to the reference signal and to output the data responsive to the comparison, and processing circuitry configured to receive the data from the comparator and to process the data.

Abstract: Wireless communication systems, radio frequency identification devices, methods of enhancing a communications range of a radio frequency identification device, and wireless communication methods are described.

Abstract: Wireless communications devices, methods of processing a wireless communication signal, wireless communication synchronization methods and a radio frequency identification device communication method are described.

Abstract: A method of securing communications in an RFID system including a reader and an RF tag having a memory configured to store information comprises sending, from the reader, a message to the tag; the tag, in response to the message, generating a challenge value and sending the challenge value to the reader; in any order: the reader performing a mathematical operation on the challenge value based upon a key value to generate a challenge reply and sending the challenge reply to the tag and the tag independently computing a challenge response based on the key value and mathematical operation; the tag comparing the challenge response computed by the tag with the challenge reply sent by the reader; and the tag authenticating the reader if the challenge response matches the challenge reply. An RFID system including an RFID tag and a reader are configured to perform the above steps.

Abstract: Radio frequency identification device communications systems, wireless communication devices, wireless communication systems, backscatter communications methods, radio frequency identification device communications methods and a wireless communication are provided.

Abstract: A method of rapidly identifying RFID tags in an RFID system including a reader and a plurality of RFID tags, the tags having respective IDs formed of a plurality of bit locations, the method comprising determining in the reader which bit locations do not add to the uniqueness of the IDs of the tags; and ignoring data in bit locations that do not add to the uniqueness of the IDs of the tags. An RFID system comprising a plurality of RFID tags, the tags having respective IDs formed of a plurality of bit locations; and an RFID reader configured to communicate with the RFID tags, the reader being configured to determine which bit locations do not add to the uniqueness of the IDs of the tags, and to ignore data in bit locations that do not add to the uniqueness of the IDs of the tags.

Abstract: An RFID system comprises an RFID reader configured to issue an RF command requesting that RF tags identify themselves, and to issue timing information defining a plurality of timeslots; and a plurality of RF tags in selective communication with the reader, the RF tags having respective IDs, respective tags being configured to randomly select a timeslot in which to reply to the RF command, and to issue an RF reply in response to the RF command in the randomly selected timeslot, the RF reply including a frequency pattern to assist in identifying the tag but not the tag's entire ID, different tags having different frequency patterns.

Abstract: Wireless communications systems, radio frequency identification devices, wireless communications methods, and radio frequency identification device communications methods are described. In one aspect, a wireless communications system includes a reader configured to output a plurality of wireless signals including different modulation frequencies and to receive a plurality of second wireless signals, a plurality of communication devices configured to receive the first wireless signals and to output the second wireless signals using backscatter modulation and wherein the communication devices are individually configured to respond to one of the first wireless signals having a first modulation frequency at a first moment in time and to respond to one of the first wireless signals having a second modulation frequency different than the first modulation frequency at a second moment in time.

Abstract: An alerting device and method to remind personnel of a risk is disclosed. The device has at least two sensors, a logic controller, a power source, and an annunciator that delivers a visual message, with or without an audible alarm, about a risk to a person when the sensors detect the person exiting a predetermined space. In particular, the present invention reminds a person of a security, safety, or health risk upon exiting a predetermined space. More particularly, the present invention reminds a person of an information security risk relating to sensitive, proprietary, confidential, trade secret, classified, or intellectual property information.