Abstract: A method for Peak to Average Power Ratio (PAPR) reduction at an input of analog to digital converter (ADC) of the receiver, the method includes mapping, by a mapper, an input symbol to an output symbol that maintains a peak power constraint at the input of the ADC; wherein the mapping is responsive to (a) previously transmitted symbols and (b) a state of the channel following a transmission of the current output symbol; transmitting the output symbol by the transmitter; receiving, by the receiver, a received symbol that represents the output symbol; and de-mapping the received symbol, by a de-mapper of the receiver, to a de-mapped symbol that represents the input symbol.

Abstract: A compact wideband RF antenna for incorporating into a planar substrate, such as a PCB, having at least one cavity with a radiating slot, and at least one transmission line resonator disposed within a cavity and coupled thereto. Additional embodiments provide stacked slot-coupled cavities and multiple coupled transmission-line resonators placed within a cavity. Applications to ultra-wideband systems and to millimeter-wave systems, as well as to dual and circular polarization antennas are disclosed.

Abstract: A method for Peak to Average Power Ratio (PAPR) reduction at an input of analog to digital converter (ADC) of the receiver, the method includes mapping, by a mapper, an input symbol to an output symbol that maintains a peak power constraint at the input of the ADC; wherein the mapping is responsive to (a) previously transmitted symbols and (b) a state of the channel following a transmission of the current output symbol; transmitting the output symbol by the transmitter; receiving, by the receiver, a received symbol that represents the output symbol; and de-mapping the received symbol, by a de-mapper of the receiver, to a de-mapped symbol that represents the input symbol.

Abstract: A method for Peak to Average Power Ratio (PAPR) reduction at an input of analog to digital converter (ADC) of the receiver, the method includes mapping, by a mapper, an input symbol to an output symbol that maintains a peak power constraint at the input of the ADC; wherein the mapping is responsive to previously transmitted symbols; transmitting the output symbol by the transmitter; receiving, by the receiver, a received symbol that represents the output symbol; and de-mapping the received symbol, by a de-mapper of the receiver, to a de-mapped symbol that represents the input symbol.

Abstract: A radar system and method for calibrating a radar system, the method including the steps of: measuring a set of azimuth angles of the radar system to obtain a plurality of measured azimuth array responses, wherein the radar system is physically rotated about a first axis of the radar system between each azimuth angle measurement; measuring a set of elevation angles of the radar system to obtain a plurality of measured elevation array responses, wherein the radar system is physically rotated about a second axis of the radar system between each elevation angle measurement; obtaining an azimuth calibration matrix based on the plurality of measured azimuth array responses and an elevation calibration matrix based on the plurality of measured elevation array responses; and configuring the radar system to apply the azimuth calibration matrix and the elevation calibration matrix to one or more antenna array responses.

Abstract: A vehicle radar system and calibration method that provide for system calibration so that target object parameters can be calculated with improved accuracy. Generally speaking, the calibration method uses a number of hypothesized calibration matrices, which represent educated guesses for possible system or array calibrations, to obtain a number of beamforming images. A blurring metric is then derived for each beamforming image, where the blurring metric is generally representative of the quality or resolution of the beamforming image. The method then selects hypothesized calibration matrices based on their blurring metrics, where the selected matrices are associated with the blurring metrics having the best beamforming image resolution (e.g., the least amount of image blurriness). The selected hypothesized calibration matrices are then used to generate new calibration matrices, which in turn can be used to calibrate the vehicle radar system so that more accurate target object parameters can be obtained.

Abstract: A vehicle radar system, such as a multiple input multiple output (MIMO) radar system, for estimating a Doppler frequency shift and a method of using the same. In one example, a modulated signal is mixed with an orthogonal code sequence and is transmitted by a transmit antenna array with a plurality of transmitting antennas. The signals reflect off of a target object and are received by a receive antenna array with a plurality of receiving antennas. Each of the received signals, which likely includes a Doppler frequency shift, is processed and mixed with a number of frequency shift hypotheses that are intended to offset the Doppler frequency shift and result in a series of correlation values. The frequency shift hypothesis with the highest correlation value is selected and used to correct for the Doppler frequency shift so that more accurate target object parameters, such as velocity, can be obtained.

Abstract: A method for Peak to Average Power Ratio (PAPR) reduction at an input of analog to digital converter (ADC) of the receiver, the method includes mapping, by a mapper, an input symbol to an output symbol that maintains a peak power constraint at the input of the ADC; wherein the mapping is responsive to previously transmitted symbols; transmitting the output symbol by the transmitter; receiving, by the receiver, a received symbol that represents the output symbol; and de-mapping the received symbol, by a de-mapper of the receiver, to a de-mapped symbol that represents the input symbol.

Abstract: A radar system and method for calibrating a radar system, the method including the steps of: measuring a set of azimuth angles of the radar system to obtain a plurality of measured azimuth array responses, wherein the radar system is physically rotated about a first axis of the radar system between each azimuth angle measurement; measuring a set of elevation angles of the radar system to obtain a plurality of measured elevation array responses, wherein the radar system is physically rotated about a second axis of the radar system between each elevation angle measurement; obtaining an azimuth calibration matrix based on the plurality of measured azimuth array responses and an elevation calibration matrix based on the plurality of measured elevation array responses; and configuring the radar system to apply the azimuth calibration matrix and the elevation calibration matrix to one or more antenna array responses.

Abstract: An example method includes estimating whether a collision occurred between a plurality of wide band response signals, the wide band response signals being responsive to a first interrogation signal transmitted by a first reader; when the collision is estimated to have occurred and the first reader received a first response from a particular tag, transmitting, by the first reader, a second interrogation signal, the second interrogation signal initiating a communication session between the reader and the particular tag; and transmitting, by the first reader, an acknowledgement packet to cause the tag to refrain from responding to a command during the communication session; and a second reader to refrain from interrogating the particular tag during the communication session.

Abstract: A vehicle radar system and calibration method that provide for system calibration so that target object parameters can be calculated with improved accuracy. Generally speaking, the calibration method uses a number of hypothesized calibration matrices, which represent educated guesses for possible system or array calibrations, to obtain a number of beamforming images. A blurring metric is then derived for each beamforming image, where the blurring metric is generally representative of the quality or resolution of the beamforming image. The method then selects hypothesized calibration matrices based on their blurring metrics, where the selected matrices are associated with the blurring metrics having the best beamforming image resolution (e.g., the least amount of image blurriness). The selected hypothesized calibration matrices are then used to generate new calibration matrices, which in turn can be used to calibrate the vehicle radar system so that more accurate target object parameters can be obtained.

Abstract: A vehicle radar system, such as a multiple input multiple output (MIMO) radar system, for estimating a Doppler frequency shift and a method of using the same. In one example, a modulated signal is mixed with an orthogonal code sequence and is transmitted by a transmit antenna array with a plurality of transmitting antennas. The signals reflect off of a target object and are received by a receive antenna array with a plurality of receiving antennas. Each of the received signals, which likely includes a Doppler frequency shift, is processed and mixed with a number of frequency shift hypotheses that are intended to offset the Doppler frequency shift and result in a series of correlation values. The frequency shift hypothesis with the highest correlation value is selected and used to correct for the Doppler frequency shift so that more accurate target object parameters, such as velocity, can be obtained.

Abstract: A method for transmit beamforming in a MIMO antenna for a radar system having N transmit antennas includes acquiring a coding matrix defining a desired field-of-view, generating a transmit signal matrix based on a singular value decomposition (SVD) of the coding matrix, wherein the columns of the transmit signal matrix are transmit signal vectors formed from the singular vectors corresponding to the maximal singular values of the coding matrix based on the SVD, the transmit signal vectors defining spatial codewords, and transmitting signals in sequences over the N transmit antennas according to the transmit signal matrix, the sequences correspond to the spatial codewords from the transmit signal vectors, wherein each sequence is defined by a number of spatial codewords transmitted in a single repetition sequence interval, and wherein transmitting the spatial codewords according to the transmit signal matrix enables beamforming of the transmitted signals to the desired field-of-view.

Abstract: A multiple input multiple output (MIMO) antenna for a radar system includes a plurality of transmitter antennas forming a planar transmitter antenna array, wherein the plurality of transmitter antennas are configured to emit orthogonal waveforms, and a plurality of receiver antennas forming at least two receiver antenna arrays, wherein along a first axis an interelement spacing between the plurality of receiver antennas in each receiver antenna array is dense relative to an interelement spacing between the plurality of transmitter antennas; and along a second axis the interelement spacing between the plurality of transmitter antennas is dense relative to the interelement spacing between the plurality of receiver antennas.

Abstract: A multiple input multiple output (MIMO) antenna for a radar system, the antenna for at least one first module having a plurality of antenna elements forming a linear array, wherein the plurality of antenna elements in the linear array are uniformly separated by a first distance; and for at least one second module having a plurality of antenna elements forming a planar array, wherein the plurality of antenna elements in the planar array are uniformly separated by a second distance; and wherein the at least one first module and the at least one second module are selectively configured to function as transmitter modules or receiver modules, and wherein an interleaving between the plurality of antenna elements in the linear array of the at least one first module with the plurality of antenna elements in the planar array of the at least one second module produces a uniform virtual antenna array.

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: An example method includes estimating whether a collision occurred between a plurality of wide band response signals, the wide band response signals being responsive to a first interrogation signal transmitted by a first reader; when the collision is estimated to have occurred and the first reader received a first response from a particular tag, transmitting, by the first reader, a second interrogation signal, the second interrogation signal initiating a communication session between the reader and the particular tag; and transmitting, by the first reader, an acknowledgement packet to cause the tag to refrain from responding to a command during the communication session; and a second reader to refrain from interrogating the particular tag during the communication session.

Abstract: The Very Light Readers of the present invention are based on an augmented Tag circuit with a preferred embodiment including at least one VLSI chip integrating a UWB front end, digital transceiver, and possibly an internal controller; a UWB Antenna; a power supply; a controller configured to implement the Media Access Control protocol of the system; a Communication Interface subsystem for connection to the system network and a clock source. Also described is a system capable of reducing collision occurrence in a network for communicating between multiple readers and a plurality of RF Tags. Tags are configured to receive interrogation signals and transmit response signals. Readers are configured to transmit interrogation signals, receive response signals, estimate the quantity of responses received to an interrogation, determine the round trip delay time of each response and estimates whether a collision between responses has occurred. If so, the Reader transmits an additional interrogation signal.

Abstract: A system of radio frequency communication between Readers and Tags having a scalable Media Access Control (MAC) protocol for an active RFID system employing multiple access. The system comprising at least one tag Reader and a plurality of Tags each having a unique tag ID and deployed in a region in which at least some of the Tags are in radio communication with the tag Reader. A multi-dimensional addressing scheme of the MAC protocol enables division of the plurality of Tags into a number of groups for different stages of MAC protocol processing, based on different portions of the tag ID. The MAC has an inherent flexibility in the sense that it allows readers to communicate with different versions of tags and also optimize communication parameters to reader's capabilities, without pre-configuration of the tags. Furthermore, the MAC supports means to achieve very high access reliability, such as relay between tags.

Abstract: A method for generating an UWB pulses based on LC oscillator topology. Fast turn on of the oscillator is achieved by creating large asymmetry in a normally symmetrical topology which is used in a typical differential type oscillator. One method for achieving large asymmetry is activating one branch of a differential pair of branches for a short duration before activating both branches in a normal operation. The bandwidth of the pulse is controlled by modifying the duration of the oscillator activation. Fast turn on and turn off is essential for high bandwidth generation. The method is adaptable for generating binary phase shift keying (BPSK) modulation. Selecting the activated branch of a fully symmetrical topology controls the output phase and creates two possibilities which differ exactly by 180 degrees. In a preferred embodiment, all the pulse generator components are on-clip leading to a low cost solution. The circuit can generate high power pulses directly on a load.