Abstract: A system capable of monitoring an area and detecting a disturbance with the area. The system has a plurality of ultra-wide band radio frequency tags, each of the tags including a digital signal processing module configured to monitor changes in radio frequency multipath properties of received packets transmitted by at least one other of the tags. Changes in the radio frequency multipath properties may be caused by a disturbance indicative of an object in the vicinity of the tags. A corresponding method is also disclosed.

Abstract: A novel and useful media access control (MAC) protocol that is intended for use over noisy shared media channels. The MAC protocol provides layer 2 functionality over a network using a shared medium including a backoff mechanism for CSMA/CA channel access, link addressing that reduces the overhead of long MAC addresses, a flooding scheme having controlled exposure for broadcast transmissions, multicast transmissions using selective ACKs, implementation of traffic prioritization using an adaptive backoff scheme, a second layer repeater establishment process and multi-packet transport for short packets and fragmentation for long packet transport.

Abstract: A method for synchronizing on a pulsed waveform sequence including pulsed waveforms. An impulse radio receiver is provided including a radio frequency (RF) front end connected to a demodulator, and the demodulator is connected to a processing unit. Power is provided to at least a portion of an RF component such as the RF front end and/or the demodulator, during time windows sufficient for testing an hypothesis regarding timing of the pulsed waveforms. The powering is controlled by the processing unit. Preferably, testing the hypothesis includes accumulating a signal of the pulsed waveforms, correlating with the pulsed waveforms, or accumulating the correlation result of the pulsed waveforms. Preferably, others functions of the receiver are powered or enabled subsequent to the testing. Preferably, the impulse radio receiver is an ultra-wide band receiver.

Abstract: The present invention relates to a method and system (10) for distance determination of RF tags (4) and its applications based on measuring the round trip delay, avoiding deterministic collisions between a plurality of wide band response signals transmitted by the tags (4) by adding a pseudo-random time delay to the wide band response signal, and iteratively reducing the collision probability between plurality of wide band response signals.

Abstract: The present invention relates to a method and system (10) for distance determination of RF tags (4) and its applications, based on measuring the round trip delay, avoiding deterministic collisions between a plurality of wide band response signals transmitted by the tags (4) by adding a pseudo-random time delay to the wide band response signal, and iteratively reducing the collision probability between plurality of wide band response signals.

Abstract: An active radio frequency identification (REID) tag implemented on a flat label. The tag includes a battery printed on the label, a flat wide-band antenna printed on the label and a wide band communication circuit implemented as a chip inlay inside the label. The circuit is attached to the battery and to the antenna. The combined thickness of the battery, the antenna and the circuit as printed on the flexible label is less than one millimeter. The battery, the antenna and the circuit are printed on the label so as to render substantial flexibility to the RFID tag. The circuit operates at a center frequency of at least one gigahertz and a bandwidth at least twenty percent of said center frequency or a bandwidth at least 500 Mhz. The tag typically includes an inaccurate clock source such as an RC circuit and does not include a crystal.

Abstract: A novel and useful acquisition and synchronization mechanism for spread spectrum communication systems whereby a synchronization sequence comprising a plurality of known symbols spaced apart by predefined time delay intervals is transmitted as the start of packet signal. At the transmitter, a synchronization sequence is transmitted at the beginning of each packet. A synchronization sequence is generated which includes a plurality of symbols with predefined time gaps between each of the symbols. Multiple synchronization sequences may be generated wherein each sequence comprises a unique set of time delays or gaps between each of the symbols. Each set of unique time delays or gaps between symbols of a sequence is stored as a synchronization sequence gap template in memory.

Abstract: A wireless local area network (WLAN) access point (AP) system comprises a first plurality of distributed remote antenna units operative to transmit and receive RF signals and a central WLAN beam-forming unit connected to each distributed remote antenna unit and operative to provide communication between the antenna units and a second plurality of wireless clients. The WLAN AP system can be used for simultaneous communications with the wireless clients over the same radio frequency (RF) channel while avoiding mutual interferences.

Abstract: A digital to analog waveform converter featuring a DSP, discrete output devices, and Multi Input Multi Output (MIMO) device, wherein the MIMO device includes low accuracy components featuring high speed and low power.

Abstract: A method for communicating between elements including a reader and tags of a radio frequency identification system. The method includes addressing a wide-band-message signal by including in the signal an identifier of the first tag. The addressed wide-band-message signal is transmitted by the reader. A first tag waits to receive the addressed wide-band-message signal; and upon receiving the addressed wide-band-message signal and recognizing the identifier, the first tag responds to the addressed wide-band-message signal by transmitting an addressed wide-band response signal either back to the reader or to a relaying tag. The tag relays to another element of the system by transferring at least one datum of the query from the addressed wide-band-message signal to the addressed wide-band response signal, where the elements are readers or tags. The system and method allow for many parallel wide band addressed links, and for position determination using at least two tags with known locations.

Abstract: A method for providing a digital output signal (59) representing an analog input signal (54) in a system (50) including an analog circuit (51) and a control unit (52). Analog circuit (51) preferably features high bandwidth, high gain, and low current consumption. Analog circuit (51) is preferably implemented with low accuracy components. Control unit (52) keeps error outputs (55) of analog circuit (51) at a minimal value so that control unit (52) cancels analog input signal(54) by outputting discrete value signals (58) in a feedback loop as input (58) to analog circuit (51). A DSP (53) of system (50) is previously trained using known analog signals and a model relating inputs (54,58) to error outputs (55) of analog circuit (51) is previously known. During operation, a digital representation (57) of the discrete value signals (58) is fed to DSP (53) that reconstructs analog input signal (54) by knowing from the prior training the effect of control unit (52) and the model of analog circuit (51).

Abstract: An active radio frequency identification (RFID) tag implemented on a flat label. The tag includes a battery printed on the label, a flat wide-band antenna printed on the label and a wide band communication circuit implemented as a chip inlay inside the label. The circuit is attached to the battery and to the antenna. The combined thickness of the battery, the antenna and the circuit as printed on the flexible label is less than one millimeter. The battery, the antenna and the circuit are printed on the label so as to render substantial flexibility to the RFID tag. The circuit operates at a center frequency of at least one gigahertz and a bandwidth at least twenty percent of said center frequency or a bandwidth at least 500 Mhz. The tag typically includes an inaccurate clock source such as an RC circuit and does not include a crystal.

Abstract: The present invention relates to a method and system (10) for distance determination of RF tags (4) and its applications based on measuring the round trip delay, avoiding deterministic collisions between a plurality of wide band response signals transmitted by the tags (4) by adding a pseudo-random time delay to the wide band response signal, and iteratively reducing the collision probability between plurality of wide band response signals.

Abstract: The present invention relates to a method and corresponding device for constructing at least one digital input signal and providing analog representation thereof, featuring a DSP, discrete output devices, and Multi Input Multi Output (MIMO) system, wherein the MIMO system, constructed from low accuracy components featuring high speed and low power, outputs the constructed analog signal equivalent to the digital input signal representation.

Abstract: A method and a corresponding system for sampling at least one analog signal (54) and providing digital representation thereof (59). Disclosed an analog circuit (51) featuring high bandwidth, high gain, and low current consumption, wherein that analog circuit is implemented by low accuracy components. The analog circuit is integrated with a control unit (52). The control unit is keeping error outputs of the system at a minimal value so that the total effect of the control unit is canceling the effect of the input signals. By knowing the effect of the control unit, the at least one analog input signals (54) can be approximated. The control unit is using discrete value signals (58). Digital representation of these discrete value signals (57) is feed to a DSP that is reconstructing the input signal by knowing the effect of the control unit and the model of the sampler.

Abstract: A method and system for a hand-held RF tag locator (6) featuring the unique method of locating the position of one or more RF tags (4) by using a directional antenna (8) enabling azimuth determination and measuring the round trip delay enabling distance determination between the hand-held RF tag (6) locator to the RF tags (4).

Abstract: A novel and useful mechanism for detecting intrusion and jamming attempts by an imposter node. A time window defined as an emergency window is reserved after the end of a packet and before an acknowledgement window. Nodes that detect the presence of an intruder transmit an emergency packet during the emergency time window to inform the receive node that the packet it received was sent from an imposter node. Attempts to jam the transmission of the emergency packet from the victim node to the receive node are detected by listening during the emergency window time period for carrier signal that indicates that an emergency packet is trying to be sent. An emergency packet request message is sent by the receive node in response which causes the victim node to resend the emergency packet.

Abstract: An apparatus for and a method of iterative equalization for communication over noisy channels suitable for use with a wide range of different types of communications systems and channels that is particularly applicable to power line based communication systems. Equalization of received symbols is achieved by iteratively removing the influence of previous symbols dispersed due to channel ISI. Equalization is performed using iterative subtraction in combination with calculations based on the inverse of the transfer matrix. The impulse response of previous symbols is subtracted out to yield the impulse response of the received symbol. The estimate of the current symbol {tilde over (B)}n is then calculated by passing the modified received symbol through a matched filer which functions to remove the effect of channel ISI from the symbol. Multiple iterations are performed to improve the accuracy of the resultant symbol decision.

Abstract: A novel and useful distributed synchronization mechanism. The synchronization loop of each station on the shared media based network considers only synchronization signals received having a time phase earlier than the time phase of its internal clock. From among the plurality of synchronization signals received by a given station having a time phase earlier than that of its internal clock, only the earliest of the received synchronization signals is considered. This allows the use of a second order synchronization tracking loop wherein both the phase and rate of the internal clock are tracked and adjusted. The station with the fastest internal clock effectively functions as an ad-hoc synchronization master for all stations in a given maximum connected group.

Abstract: A novel media access control (MAC) mechanism utilizing synchronization signaling that enables nodes from different networks having different technologies and protocols to coexistence using the same shared media. The present invention is suitable for use with a wide range of different types of network and technologies and is particularly useful in providing coexistence capabilities to powerline based data communication systems. Specific time slots are assigned for the transmission of a frame occupation signal to indicate to all nodes that the channel is occupied. A synchronization signal is randomly transmitted during a preassigned time slot within the frame to provide accurate timing for the frame occupation signal. During times that a node does not transmit the synchronization signal, it listens to the channel. A timing signal is derived from the synchronization signals received from other nodes during this quiet period wherein the node is in a listening mode.