A method and apparatus for tracking items automatically is described. A passive RFID (Radio Frequency IDentification) tag is used with a material tracking system capable of real-time pinpoint location and identification of thousands of items in production and storage areas. Passive RFID tags are attached to the item to be tracked, remote sensing antennas are placed at each remote location to be monitored, interrogators with several antenna inputs are connected to the sensing antennas to multiplex the antenna signals, and a host computer communicates with the interrogators to determine item locations to an exacting measure.

RFID material tracking method and apparatus

The present invention teaches a communications system comprising a first communications device for receiving data and a wake up signal. The first communications device comprises an active mode of operation and a sleep mode of operation for reducing power consumption. Further, the system comprises means for switching the first communications device to and from sleep mode in response to receiving the wake up signal. Further, the system comprises a second communications device for transmitting data to the first device during its active mode, while transmitting the wake up signal to the first device during its sleep mode.

Wake up device for communications system

An exemplary embodiment uses a novel adaptation of a tree splitting algorithm applied to Radio Frequency (RE) tagging technology to identify many tags in the RF field of a base station. The embodiment uses the tree splitting algorithm to identify a single tag in a field of a plurality of radio frequency tags. Once the single tag is identified, the identified tag is placed in a Data_Exchange state where the base station can access data from the tag memory by using information that identifies the tag.

Multiple item radio frequency tag identification protocol

A wireless communications apparatus includes a wake-up receiver adapted to receive a wake-up signal and an initially powered-off, sleeping wireless communications transceiver. When the wake-up receiver receives the wake-up signal, it can in turn power on the wireless communications transceiver. In another aspect, the invention includes an apparatus for sending a wake-up signal to the wake-up receiver. The wake-up transmitter and the wake-up receiver can communicate via a variety of wireless communications protocols, including the BLUETOOTH™ standard.

Device with passive receiver

A method of communicating between an interrogator (10) and at least a first and second transponder (12). The transponders (12) are separately located within a first and a second vehicle (20) travelling within a first and a second traffic lane, respectively. The method has the steps of providing a first and a second LF antenna (16) associated with and proximity to a first and a second traffic lane, respectively. From each of the first and second LF antennas (16) a continuous LF subcarrier is transmitted to serve as a clock signal for each antenna's associated transponder (12). Initially, a wake-up signal is sent by each of the LF antennas (16) to its associated transponder (12). Following the wake-up signal, a unique lane code is sent by each of the LF antennas (16) to its associated transponder (12). The transponder (12) stores its unique lane code in its memory (70). The transponder then sends a UHF response in a pre-determined time period depending on the unique lane code stored in each of the transponders (12). The time period in which the transponder (12) sends its UHF response is unique to that transponder (12) so that interference between responding transponders (12)is avoided. Other devices, systems and methods are also disclosed.

Transponder systems for automatic identification purposes

An interrogation responder system composed of a transmitter stationarily mounted in a certain fixed place and a receiver mounted on a mobile object. The receiver on the mobile side starts the operation when a power is supplied to the entire circuit in accordance with a wake-up signal from the transmitter on the fixed side so as to modulate the electromagnetic signal emitted from the transmitter on the fixed side in accordance with a predetermined code and reflect a response. This enables continuing bilateral communication of a command, data and so forth. By starting communication between the transmitter and the receiver by a direct wave of a carrier signal in a microwave band after sensing that the receiver on the mobile side has entered a good communication zone, secure communication is enabled at a sufficient electric field strength.

Interrogator/transponder system and mobile transponder device

A mobile communication system comprising communication equipment provided on the fixed side and communication equipment provided on the mobile side. The mobile communication equipment starts to operate when its whole circuit is powered in response to a start signal from the fixed communication equipment. The mobile equipment modulates the electromagnetic waves radiated from the fixed communication equipment and returns the response, in order to continue the bidirectional communication of instructions and data. When it is detected by entrance detect means that the mobile communication equipment has entered a favorable communication range, communication is started between both sides by direct waves in the microwave band, to reliably carry out the communication maintaining sufficiently strong electromagnetic wave intensity.

Souichi Isikawa

Papers

Interrogator/transponder system and mobile transponder device

Mobile communication system and mobile communication equipment