MIMO radar signals using Doppler code multiplexing

Abstract

The integrated circuit may include K transmit circuits that output K transmit signals, where K is a non-zero integer, and the K transmit signals are encoded using a first Doppler code multiplexing. Additionally, the integrated circuit may include L receive circuits that provide L receive signals (which may correspond to the K transmit signals), where L is a non-zero integer, and the L receive signals are encoded using a second Doppler code multiplexing. Note that the first and / or second Doppler code multiplexing may be different from Doppler division multiplexing. Additionally, the first Doppler code multiplexing may multiplex the kth transmit signal among the K transmit signals in bin n between chirps in a frame. k The second Doppler code multiplexing may include selectively Doppler shifting the l-th received signal among the L transmitted signals by bin n between the chirps in the frame. l This may include selectively Doppler shifting by a factor of 1.

Description

[Technical Field]

[0001] The present disclosure relates to techniques for encoding multiple-input multiple-output (MIMO) radar signals using Doppler code multiplexing. [Background technology]

[0002] To provide improved safety and convenience for transportation, many automobile manufacturers are equipping vehicles with additional sensors and / or features. For example, autonomous vehicles typically include a wide variety of sensors, such as acoustic and / or electromagnetic sensors, that monitor the surrounding environment to detect other vehicles, people, animals, or obstacles. However, attempts to detect and mitigate the effects of interference with these sensors have not been entirely satisfactory and often degrade the performance of the associated features. Summary of the Invention [Problem to be solved by the invention]

[0003] A first integrated circuit embodiment is described, which includes K transmit circuits outputting K transmit signals, where K is a non-zero integer, and the K transmit signals are encoded using a first Doppler code multiplexing.

[0004] Note that the first Doppler code multiplexing may be different from the Doppler division multiplexing.

[0005] Furthermore, a given transmission signal among the K transmission signals may include M chirps in a frame, where M is a non-zero integer.

[0006] Furthermore, in the first Doppler code multiplexing, the kth transmission signal among the K transmission signals is assigned to bin n kbins n, such that the Doppler spectrum corresponding to one or more reflected signals from a single target may have a peak-to-sidelobe ratio (PSLR) greater than or exceeding a predefined value (e.g., a predefined value associated with Doppler division multiplexing). k A selective Doppler shift of M chirps may be selectively applied among the M chirps within a frame in the kth transmitted signal. Note that the Doppler spectrum may correspond to an autocorrelation function performed on one or more reflected signals. [Means for solving the problem]

[0007] In addition, in the first Doppler code multiplexing, the Doppler shifted n k Phase shifts corresponding to bins may be selectively applied among the M chirps within a frame in the kth transmit signal. In some embodiments, the differences between the phase shifts selectively applied to different pairs of transmit signals in the K transmit signals may be different. Note that the differences between the phase shifts applied to a given pair of transmit signals in the K transmit signals may be unique or non-recurring among the set of differences between phase shifts applied to different pairs of transmit signals in the K transmit signals.

[0008] Additionally, the K transmit signals may be encoded using a bipolar phase code (such as a Barker code), which varies the phase of a given transmit signal (such as to M chirps) among the K transmit signals in a given frame. In some embodiments, the bipolar phase code may include nested Barker codes.

[0009] Additionally, the first integrated circuit may perform beamforming of the K transmit signals.

[0010] Another embodiment provides a second integrated circuit including L receiver circuits that provide L receive signals (which may correspond to the K transmit signals), where L is a non-zero integer, and where the L receive signals are encoded using a second Doppler code multiplexing.

[0011] Note that the second Doppler code multiplexing may be different from the Doppler division multiplexing.

[0012] Furthermore, a given received signal among the L received signals may include M chirps within a frame.

[0013] Furthermore, in the second Doppler code multiplexing, the l-th received signal among the L received signals is assigned to bin n l For example, bin n l A selective Doppler shift may be selectively applied among the M chirps within a frame in the l-th received signal.

[0014] In addition, in the second Doppler code multiplexing, the Doppler shifted n l Phase shifts corresponding to bins may be selectively applied among M chirps within a frame in the lth received signal. In some embodiments, the differences between the phase shifts selectively applied to different pairs of received signals in the L received signals may be different. Note that the differences between the phase shifts applied to a given pair of received signals in the L received signals may be unique or non-repeating in the set of differences between phase shifts applied to different pairs of received signals in the L received signals.

[0015] Furthermore, the second integrated circuit may be configured to calculate a Doppler spectrum using the L received signals, the Doppler spectrum having a PSLR greater than or exceeding a predefined value (such as a predefined value associated with Doppler division multiplexing). Note that the Doppler spectrum may correspond to an autocorrelation function performed on the L received signals.

[0016] Furthermore, the Doppler spectrum may be calculated using a matched filter corresponding to the first and / or second Doppler code multiplexing. For example, the Doppler spectrum may be implemented in the time domain by multiplying the L received signals with the matched filter, or in the frequency domain by convolving the Fourier transform of the L received signals with the Fourier transform of the matched filter.

[0017] Additionally, the L received signals may be encoded using a bipolar phase code (such as a Barker code), which varies the phase of a given received signal among the L received signals in a given frame. Note that the bipolar phase code may include nested Barker codes.

[0018] In some embodiments, the second integrated circuit may perform sidelobe cancellation techniques, which may include, for example, recursive coherent sidelobe estimation, non-coherent sidelobe estimation, and / or inter-frame processing.

[0019] Additionally, the second integrated circuit may perform beamforming of the L received signals.

[0020] Furthermore, the second integrated circuit may encode the L received signals using second Doppler code multiplexing when downconverting the L received signals to baseband or to an intermediate carrier frequency (such as a carrier frequency within the frequency band of the radar) different from one or more carrier frequencies of the K transmitted signals.

[0021] In another embodiment, a system is provided, comprising a first integrated circuit and a second integrated circuit. The first integrated circuit includes K transmit circuits that output K transmit signals, where K is a non-zero integer, and the K transmit signals are encoded using a first Doppler code multiplexing. Furthermore, the second integrated circuit includes L receive circuits that provide L receive signals (which may correspond to the K transmit signals), where L is a non-zero integer, and the L receive signals are encoded using a second Doppler code multiplexing.

[0022] It should be noted that the first and / or second Doppler code multiplexing may be different from the Doppler division multiplexing.

[0023] Furthermore, a given transmit signal among the K transmit signals may include M chirps in a frame, where M is a non-zero integer, and a given receive signal among the L receive signals may include M chirps in a frame.

[0024] In addition, in the first Doppler code multiplexing, the kth transmission signal among the K transmission signals is assigned to bin n k For example, bin n k The selective Doppler shift may be selectively applied among the M chirps within a frame in the kth transmitted signal. In some embodiments, in the second Doppler code multiplexing, the lth received signal among the L received signals is assigned to bin n l For example, bin n l A selective Doppler shift may be selectively applied among the M chirps within a frame in the l-th received signal.

[0025] Furthermore, in the first Doppler code multiplexing, the Doppler shifted n k Phase shifts corresponding to bins may be selectively applied among the M chirps within a frame in the kth transmit signal. Furthermore, the differences between the phase shifts selectively applied to different pairs of transmit signals in the K transmit signals may be different. In addition, the differences between the phase shifts applied to a given pair of transmit signals in the K transmit signals may be unique or non-repeating among the set of differences between phase shifts applied to different pairs of transmit signals in the K transmit signals.

[0026] In the second Doppler code multiplexing, the Doppler shifted n l Note that phase shifts corresponding to bins may be selectively applied among M chirps within a frame in the lth received signal. Furthermore, the differences between the phase shifts selectively applied to different pairs of received signals in the L received signals may be different. In addition, the differences between the phase shifts applied to a given pair of received signals in the L received signals may be unique or non-repeating in the set of differences between phase shifts applied to different pairs of received signals in the L received signals.

[0027] In some embodiments, the second integrated circuit may be configured to calculate a Doppler spectrum using the L received signals, the Doppler spectrum having a PSLR greater than or exceeding a predefined value (such as a predefined value associated with Doppler division multiplexing). Note that the Doppler spectrum may correspond to an autocorrelation function performed on the L received signals.

[0028] Furthermore, the Doppler spectrum may be calculated using a matched filter corresponding to the first and / or second Doppler code multiplexing. For example, the Doppler spectrum may be implemented in the time domain by multiplying the L received signals with the matched filter, or in the frequency domain by convolving the Fourier transform of the L received signals with the Fourier transform of the matched filter.

[0029] Furthermore, L may be different from K. For example, K may be 4 and L may be 2.

[0030] Additionally, the first Doppler code multiplexing may be different from the second Doppler code multiplexing.

[0031] In some embodiments, the K transmit signals and / or the L receive signals may be encoded using one or more bipolar phase codes (such as Barker codes) that vary the phase of a given transmit signal among the K transmit signals and / or a given receive signal among the L receive signals within a given frame. Note that the one or more bipolar phase codes may include nested Barker codes. In some embodiments, a first bipolar phase code used in a first integrated circuit is different from a second bipolar phase code used in a second integrated circuit.

[0032] Additionally, the second integrated circuit may perform sidelobe cancellation techniques, for example, the sidelobe cancellation techniques may include recursive coherent sidelobe estimation, non-coherent sidelobe estimation, and / or inter-frame processing.

[0033] Additionally, the first integrated circuit may perform beamforming of the K transmit signals and / or the second integrated circuit may perform beamforming of the L receive signals.

[0034] In addition, the second integrated circuit may encode the L received signals using second Doppler code multiplexing when downconverting the L received signals to baseband or to an intermediate carrier frequency different from one or more carrier frequencies of the K transmitted signals.

[0035] Another embodiment provides an integrated circuit that includes the functionality of a first integrated circuit and a second integrated circuit.

[0036] Another embodiment provides an electronic device including the first integrated circuit and / or the second integrated circuit.

[0037] Another embodiment provides a method for communicating an encoded signal, the method including at least some of the operations performed by a first integrated circuit and / or a second integrated circuit.

[0038] This Summary is presented for the purposes of illustrating some exemplary embodiments to aid in a basic understanding of some aspects of the subject matter described herein. Accordingly, it will be understood that the features described above are examples and should not be construed as narrowing the scope or spirit of the subject matter described herein. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following Detailed Description, Figures, and Claims. [Brief explanation of the drawings]

[0039] [Figure 1] 1 is a diagram illustrating an example of a vehicle equipped with a radar sensor according to some embodiments of the present disclosure. [Figure 2] FIG. 1 is a block diagram illustrating an example of a driver assistance system according to some embodiments of the present disclosure. [Figure 3] FIG. 1 is a block diagram illustrating an example of a radar system according to some embodiments of the present disclosure. [Figure 4]FIG. 1 is a block diagram illustrating an example of a radar system according to some embodiments of the present disclosure. [Figure 5A] 1 is a diagram illustrating an example of a comparison of the magnitude of a transfer function for a matched filter and the magnitude of a corresponding ambiguity function associated with Doppler division multiplexing and Doppler code multiplexing, in accordance with some embodiments of the present disclosure. [Figure 5B] 1 is a diagram illustrating an example of a comparison of the magnitude of a transfer function for a matched filter and the magnitude of a corresponding ambiguity function associated with Doppler division multiplexing and Doppler code multiplexing, in accordance with some embodiments of the present disclosure. [Figure 5C] 1 is a diagram illustrating an example of a comparison of the magnitude of a transfer function for a matched filter and the magnitude of a corresponding ambiguity function associated with Doppler division multiplexing and Doppler code multiplexing, in accordance with some embodiments of the present disclosure. [Figure 5D] 1 is a diagram illustrating an example of a comparison of the magnitude of a transfer function for a matched filter and the magnitude of a corresponding ambiguity function associated with Doppler division multiplexing and Doppler code multiplexing, in accordance with some embodiments of the present disclosure. [Figure 6] 1 is a diagram illustrating an example of a matched filter that supports Doppler code multiplexing in a transmission circuit according to some embodiments of the present disclosure. [Figure 7A] 1 is a drawing illustrating an example of a comparison of a pulse with autocorrelation of a pulse and of a pulse encoded using a Barker code, in accordance with some embodiments of the present disclosure. [Figure 7B] 1 is a drawing illustrating an example of a comparison of a pulse with autocorrelation of a pulse and of a pulse encoded using a Barker code, in accordance with some embodiments of the present disclosure. [Figure 7C] 1 is a drawing illustrating an example of a comparison of a pulse with autocorrelation of a pulse and of a pulse encoded using a Barker code, in accordance with some embodiments of the present disclosure. [Figure 7D]1 is a drawing illustrating an example of a comparison of a pulse with autocorrelation of a pulse and of a pulse encoded using a Barker code, in accordance with some embodiments of the present disclosure. [Figure 8] 1 is a diagram illustrating an example of a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a slow target according to some embodiments of the present disclosure. [Figure 9] 1 is a diagram illustrating an example of a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target according to some embodiments of the present disclosure. [Figure 10] 1 is a drawing illustrating an example of a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target and encoded using Doppler code multiplexing, in accordance with some embodiments of the present disclosure. [Figure 11A] 1 is a diagram illustrating an example of a comparison of the Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target with the Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target and encoded using Doppler code multiplexing, in accordance with some embodiments of the present disclosure. [Figure 11B] 1 is a diagram illustrating an example of a comparison of the Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target with the Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target and encoded using Doppler code multiplexing, in accordance with some embodiments of the present disclosure. [Figure 12] 1 is a diagram illustrating an example of a Doppler spectrum corresponding to a noisy transmission signal reflected from a target and encoded using Doppler code multiplexing, in accordance with some embodiments of the present disclosure. [Figure 13] 1 is a drawing illustrating an example of a Doppler spectrum corresponding to a transmitted signal reflected from multiple targets and encoded using Doppler code multiplexing, in accordance with some embodiments of the present disclosure. [Figure 14A]1 is a diagram illustrating an example of a comparison of two Doppler spectra for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing, and a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing with sidelobe rejection, in accordance with some embodiments of the present disclosure. [Figure 14B] 1 is a diagram illustrating an example of a comparison of two Doppler spectra for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing, and a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing with sidelobe rejection, in accordance with some embodiments of the present disclosure. [Figure 14C] 1 is a diagram illustrating an example of a comparison of two Doppler spectra for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing, and a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing with sidelobe rejection, in accordance with some embodiments of the present disclosure. [Figure 15] FIG. 2 is a block diagram illustrating an example of a first integrated circuit according to some embodiments of the present disclosure. [Figure 16] FIG. 10 is a block diagram illustrating an example of a second integrated circuit according to some embodiments of the present disclosure. [Figure 17] FIG. 1 is a block diagram illustrating an example of a system including a first integrated circuit and a second integrated circuit according to some embodiments of the present disclosure. [Figure 18] FIG. 1 is a block diagram illustrating an example of an integrated circuit according to some embodiments of the present disclosure. [Figure 19A] 1 is a diagram illustrating an example of a Doppler spectrum for a received signal reflected from a target and corresponding to a transmitted signal using nested transmit and receive Doppler code multiplexing and corresponding ambiguity functions, in accordance with some embodiments of the present disclosure. [Figure 19B] 1 is a diagram illustrating an example of a Doppler spectrum for a received signal reflected from a target and corresponding to a transmitted signal using nested transmit and receive Doppler code multiplexing and corresponding ambiguity functions, in accordance with some embodiments of the present disclosure. [Figure 20A] 1 is a diagram illustrating an example of a comparison of an ambiguity function corresponding to a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing in a transmit circuit and a receive circuit, and an ambiguity function corresponding to a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing and a Barker code in a transmit circuit and a receive circuit, in accordance with some embodiments of the present disclosure. [Figure 20B] 1 is a diagram illustrating an example of a comparison of an ambiguity function corresponding to a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing in a transmit circuit and a receive circuit, and an ambiguity function corresponding to a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing and a Barker code in a transmit circuit and a receive circuit, in accordance with some embodiments of the present disclosure. [Figure 21] 1 is a flow diagram illustrating an example of a method for communicating an encoded signal according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0040] It should be noted that like reference numbers refer to corresponding parts throughout the drawings. Additionally, multiple instances of the same part are designated by a common prefix separated from the instance number by a dash.

[0041] An integrated circuit for communicating coded signals is described. The integrated circuit may include K transmit circuits that output K transmit signals, where K is a non-zero integer, and the K transmit signals are encoded using a first Doppler code multiplexing. Additionally, the integrated circuit may include L receive circuits that provide L receive signals (which may correspond to the K transmit signals), where L is a non-zero integer, and the L receive signals are encoded using a second Doppler code multiplexing. Note that the first and / or second Doppler code multiplexing may be different from Doppler division multiplexing. Furthermore, the first Doppler code multiplexing may multiplex the kth transmit signal among the K transmit signals in bin n between chirps in a frame. k The second Doppler code multiplexing may include selectively Doppler shifting the l-th received signal among the L transmitted signals by bin n between the chirps in the frame. l In addition, the K transmit signals and / or the L receive signals may be encoded using a bipolar phase code, such as a Barker code or a nested Barker code.

[0042] By transmitting coded signals via communications, these circuit techniques may provide good waveform orthogonality among the K transmit circuits and / or the L receive circuits. In particular, the PSLR in the Doppler spectrum corresponding to the L receive signals may be greater than a predefined value, such as a predefined value associated with Doppler division multiplexing. Furthermore, the circuit techniques may not affect the unambiguous velocity or the maximum range of radial velocities that can be measured by the integrated circuit. As a result, these circuit techniques may enable the use of MIMO and improve the performance of radar measurements performed using the integrated circuit.

[0043] In the following description, a vehicle may include an automobile, a sport utility vehicle, a truck, a motorcycle, a train, an aircraft, a boat, or other type of transportation vehicle, however, in the following description, an automobile is used as an illustrative example of a vehicle.

[0044] Furthermore, in the following description, the vehicle may use one or more types of sensors to perform measurements related to objects in the surrounding environment. While a wide variety of types of sensors may be used, in the following description, a radar sensor is used as an illustrative example. The radar sensor may perform measurements using at least one of various modes of operation (such as pulsed wave or continuous wave) and may involve the use of one or more types of modulation (such as amplitude, frequency, and / or phase modulation). In some embodiments, a frequency-modulated continuous wave (FMCW) radar is used. Furthermore, transmitted and received radar signals (e.g., having a carrier frequency within a radar frequency band, such as between 3 MHz and 100 GHz) may be generated and / or processed in the analog and / or digital domains.

[0045] Next, we will describe embodiments of the circuit technology. FIG. 1 presents a diagram illustrating an example of a vehicle 110 equipped with an array of radar antennas, including an antenna 112 for short-range sensing (e.g., for parking assistance), an antenna 114 for medium-range sensing (e.g., for monitoring traffic jams and cut-in events), and an antenna 116 for long-range sensing (e.g., for adaptive cruise control and collision warning), each of which may be located behind the front bumper cover. An antenna 118 for short-range sensing (e.g., for backup assist) and an antenna 120 for medium-range sensing (e.g., for rear collision warning) may be located behind the back bumper cover. Additionally, an antenna 122 for short-range sensing (e.g., for blind spot monitoring and side obstacle detection) may be located behind the vehicle's fender. Each antenna and each set of antennas may be grouped into one or more arrays. Furthermore, each array may be controlled by a radar array controller 205 (FIG. 2). In some embodiments, a given set of antennas may perform multiple-input, multiple-output (MIMO) radar sensing. The type, number, and configuration of sensors in sensor arrangements for vehicles with driver assistance and autonomous driving functions vary. A vehicle may employ sensor arrangements to detect and measure distance / direction to objects within various detection zones, allowing the vehicle to navigate while avoiding other vehicles and obstacles. While the preceding description illustrates vehicle 110 with radar sensors, in other embodiments, vehicle 110 may include additional types of sensors, such as LiDAR, ultrasonic sensors, cameras, etc.

[0046] FIG. 2 presents a block diagram illustrating an example driver assistance system. The driver assistance system may include an electronic control unit (ECU) 210 at the center of a star topology, coupled to various sensors 212 and a radar array controller 214. However, other topologies may include serial, parallel, and hierarchical (tree) topologies. The radar array controller 214 may be coupled to transmit and receive antennas (e.g., in antenna 114) to transmit electromagnetic waves, receive reflections, and determine the spatial relationship of the vehicle to its surroundings. Additionally, the radar array controller 214 may be coupled to a carrier signal generator. In some embodiments, the radar array controller 214 may control the timing and sequence of operation of multiple carrier signal generators.

[0047] To provide automated parking assistance, ECU 210 may be coupled to a set of actuators, such as a turn signal actuator 216, a steering actuator 218, a braking actuator 220, and / or a throttle actuator 222. Additionally, ECU 210 may be coupled to an interactive user interface 224 for accepting user input and displaying various measurements and system status.

[0048] Using the user interface 224, sensors, and actuators, the ECU 210 may provide automatic parking, park assist, lane change assist, obstacle and blind spot detection, autonomous driving, and / or other desirable functions. During operation of the vehicle 110 (FIG. 1), sensor measurements may be obtained by the ECU 210 and used by the ECU 210 to determine the status of the vehicle 110. Furthermore, the ECU 210 may act based on the status and input information to activate signaling and control transducers to coordinate and maintain the operation of the vehicle 110. For example, operations that may be provided by the ECU 210 include driver assistance functions such as automatic parking, lane following, automatic braking, and automatic driving.

[0049] Additionally, to obtain measurements, ECU 210 may employ a MIMO radar system. Radar systems operate by emitting electromagnetic waves that propagate outward from a transmit antenna, which then reflects the waves toward a receive antenna. A reflector may be any reasonably reflective object within the path of the emitted electromagnetic waves. By measuring the propagation time of the electromagnetic waves from the transmit antenna to the reflector and back to the receive antenna, the radar system can determine the distance to the reflector. Additionally, by measuring the Doppler shift of the electromagnetic waves, the radar system can determine the velocity of the reflector relative to vehicle 110 (FIG. 1). When multiple transmit or receive antennas are used, or when multiple measurements are taken at different locations, the radar system can determine the direction to the reflector and thereby track the location of the reflector relative to vehicle 110 (FIG. 1). With more advanced processing, multiple reflectors may be tracked. In some embodiments, the radar system may employ array processing to "scan" a directional beam of electromagnetic waves and build a circumferential image of the environment around vehicle 110 (FIG. 1). In general, pulsed and / or continuous wave implementations of radar systems may be implemented.

[0050] FIG. 3 presents a block diagram illustrating an example of a radar system 310 having a MIMO configuration in which J transmitters are collectively coupled to M transmit antennas 312 to transmit transmit signals 316, where J and M are nonzero integers. The M possible transmit signals 316 may reflect from one or more reflectors or targets 314 and be received as receive signals 318 via N receive antennas 320 coupled to P receivers, where N and P are nonzero integers. Each receiver may extract the amplitude and phase or propagation delay associated with each of the M transmit signals 316, thereby enabling the system to obtain N·M measurements (although only J·P of the measurements may be obtained simultaneously). The processing requirements associated with each receiver extracting the J measurements may be reduced through the use of time-division multiplexing and / or orthogonal coding. Furthermore, available antennas may be systematically multiplexed to available transmitters and receivers to collect a complete set of measurements for radar imaging.

[0051] FIG. 4 presents a block diagram illustrating an example of a radar transceiver circuit 410 (e.g., in the radar system 310 of FIG. 3 ). In some embodiments, the radar transceiver circuit 410 is implemented as an integrated circuit within a packaged chip. The radar transceiver circuit 410 may include a carrier signal (chirp) generator 412, a phase shifter 414 (and, more generally, an encoder circuit, which may implement Doppler code multiplexing), an amplifier 416, and / or a transmit antenna 312 that can transmit a signal 316 based at least in part on the output of the carrier signal generator 412. Additionally, the radar transceiver circuit 410 may include a receive antenna 320, a low-noise amplifier (LNA) 418, and / or a mixer 420 (which, in some embodiments, may implement Doppler code multiplexing). The mixer 420 may mix the received signal 318 detected by the receive antenna 320 with the signal from the carrier signal generator 412. Additionally, a low-noise amplifier 418 may be used to amplify the received signal 318 detected by the receive antenna 320. In some embodiments, the radar transceiver circuit 410 may include a sensitivity time controller and equalizer (not shown), a wideband (BB) filter 422, an analog-to-digital converter (ADC) 424, and / or a processor 426 (e.g., the ECU 210 and / or the radar array controller 214 of FIG. 2) to perform further processing (such as a Fourier transform) of the received signal. In some embodiments, the processor 426 and the low-noise amplifier 418 may be coupled for bidirectional communication.

[0052] Additionally, in some embodiments, the carrier signal generator 412 may be coupled to the radar array controller 214 (FIG. 2). The carrier signal generator 412 may include a chirp generator for generating an FMCW signal. The chip rate of the carrier signal generator 412 may be controlled by the radar array controller 214 (FIG. 2). In some embodiments, the carrier signal generator 412 may be deactivated by the radar array controller 214 (FIG. 2) to provide an unmodulated carrier signal. Furthermore, the carrier signal generator 412 may be implemented as a local oscillator (LO) signal generator, a fractional-N phase-locked loop (PLL) with a ΣΔ controller, or a direct digital synthesis generator.

[0053] Further, the carrier signal generator 412 may be coupled to the transmit antenna 312 via a phase shifter 414 and an amplifier 416. The carrier signal generator 412 may be coupled to the receive antenna 320 through a mixer 420 and a low-noise amplifier 418. In addition, the carrier signal generator 412 may generate a transmit signal (e.g., a chirp signal). The amplifier 416 may receive the transmit signal from the carrier signal generator 412, and a transmit signal 316 corresponding to the transmit signal from the carrier signal generator 412 may be transmitted using the transmit antenna 312.

[0054] In some embodiments, the radar transmitter may include a phase rotator, a binary phase modulator, a variable gain amplifier, a switch, a power amplifier driver, a power amplifier, and / or a digital signal processor (DSP). Additionally, in some embodiments, the radar transmitter may include a digital controller. This digital controller may be included in the DSP or may be a separate component. Furthermore, the phase rotator may be used for digital phase modulation. Additionally, the radar transmitter may use a wave modulation power amplifier in a digital envelope modulation technique.

[0055] To obtain good spatial and angular resolution for ranging and detection, many radar systems use phased arrays, but cost and power consumption constraints can limit the number of elements in a phased array.

[0056] These limitations are typically addressed in various ways. For example, digital beamforming in the receive circuitry may be used to overlap different phases, thereby allowing for simultaneous viewing in multiple directions. Alternatively, or in addition, in a virtual transmit array, the size of the transmit array is effectively increased when the transmit signals from multiple transmit circuits are orthogonal to each other.

[0057] Furthermore, in some radar system architectures, the intermediate frequency chain and analog-to-digital converter (ADC), which may occupy a large area on an integrated circuit or die, may be shared with multiple radio frequency front ends, each of which may include a low-noise amplifier and a mixer electrically coupled to an antenna. This approach may reduce cost and improve resolution. In some embodiments, time-domain multiplexing (TDM) may be used to switch the radio frequency front ends on and off. Alternatively, or in addition, a modulator (such as a phase shifter) may be used to modulate the transmit signal and demodulate the receive signal, so they can be processed simultaneously without interference.

[0058] Furthermore, it can be difficult to phase modulate the radar transmitter (e.g., transmit circuitry) and / or receiver (e.g., receive circuitry) without adversely affecting the FMCW signal (which can adversely affect time-of-flight measurements and, therefore, measurement range). In FMCW, a predefined sequence of chirps (i.e., predefined variations in frequency as a function of time) is applied to the transmit signal. The corresponding receive signal can be stored in an array. In particular, there can be 512 samples per row or chirp in the array. Furthermore, columns in the array can contain instances of samples from each of the chirps, which can provide phase or Doppler information. Note that a two-dimensional fast Fourier transform (FFT) along different dimensions of the array can provide range, Doppler or velocity, or angle information.

[0059] As mentioned above, modulation of the transmitted signal can be implemented using phase shifters (e.g., phase encoding). This results in modulation of the phase of each chirp, which can result in a Doppler shift across multiple chirps. In particular, Doppler shift can be determined by measuring how the phase pattern repeats across M chirps. Thus, phase encoding can improve angular resolution, but at the cost of velocity resolution.

[0060] As a result, achieving orthogonality between radar transmitters and / or receivers can be difficult, and it is often assumed that orthogonality between radar transmitters and / or receivers can be achieved by TDM and / or Doppler division multiplexing. However, both of these approaches can adversely affect unambiguous speeds.

[0061] The disclosed circuit technology describes a matched filter-based Doppler code multiplexing technique that does not affect unambiguous velocity. This Doppler code multiplexing technique can be used in MIMO radar. Furthermore, the Doppler code multiplexing technique can provide very good waveform orthogonality even when applied to transmit and receive arrays. However, the Doppler code multiplexing technique can incur the cost of increased complexity, as it may be necessary to identify and reduce or eliminate matched filter sidelobes, which can appear as ghost targets in the Doppler spectrum.

[0062] 5A-5D present diagrams illustrating an example of a comparison of the magnitude of a transfer function for a matched filter and the magnitude of a corresponding ambiguity function associated with Doppler division multiplexing and Doppler code multiplexing, according to some embodiments of the present disclosure. While Doppler code multiplexing can be applied in the transmit array and / or the receive front-end array, the following description uses its use in a K-element transmit array as an example. In particular, the waveform transmitted by the kth transmit circuit of the transmit array is the waveform transmitted in bin n. T,k The K transmit circuits may be Doppler shifted by N sections, such that the reflections of a single target on the K transmit circuits may form a low-ambiguity pattern in the Doppler spectrum, thereby allowing for improved or optimal estimation of target velocity by matched filtering (cross-correlation) in the Doppler domain after reception. Note that Doppler code multiplexing is not the same as Doppler division multiplexing. Instead, it is a Doppler code division technique. Doppler division multiplexing may be considered a special case of Doppler code multiplexing. Because Doppler code multiplexing does not divide the Doppler spectrum into N sections (as in Doppler division multiplexing), velocity resolution may not be adversely affected.

[0063] Figure 5A shows the TFigure 5B presents the magnitude of the transfer function for the matched filter for Doppler division multiplexing where σ = {0, 8, 16, 24}. Additionally, Figure 5B presents the corresponding ambiguity function. Note that the PSLR is 4 / 4 or 0 dB, and the integrated sidelobe ratio (ISLR) is 4 / 12 or -9.5 dB.

[0064] Furthermore, Figure 5C shows that n T Figure 5D presents the magnitude of the transfer function for the matched filter for Doppler division multiplexing where σ = {0, 2, 6, 14}. Additionally, Figure 5D presents the corresponding ambiguity function. Note that the PSLR is 4 / 1 or 12 dB, and the ISLR is 4 / 12 or -9.5 dB. In Doppler code multiplexing, the main beam can have zero velocity with side lobes.

[0065] During or in Doppler code multiplexing, n T,k To apply a bit Doppler shift,

[0066]

number

[0067] A constant phase shift of

[0068]

number

[0069] where:

[0070]

number

[0071] is the phase step and M is the number of chirps per frame. To minimize Doppler ambiguity, n TThe differences between elements in may need to be unique or non-repeating. n T,i -n T,j ≠n T,i -n T,k where i, j, k are elements of [1,K] with i≠j≠k.

[0072] The Doppler domain matched filter is T may be a non-sparse zero-padded M-element vector representation of h m =[0… n T,0 0… n T,1 0… n T,K-1 …0] Furthermore, convolution with a matched filter yields the received signal (Doppler spectrum) and the transmitted signal f as follows: m can be interpreted as a cross-correlation with

[0073]

number

[0074] For example, if a 32-bit spectrum is assumed, then n T 6, which provides a diagram illustrating an example of a matched filter corresponding to Doppler code multiplexing in a transmission circuit according to some embodiments of the present disclosure. Furthermore, the operation of the matched filter is

[0075]

number

[0076] can be expressed as where S D、filt is the filtered Doppler spectrum, and i D is the bin index, and S D is the raw Doppler spectrum.

[0077] Furthermore, Barker codes are a class of pulse compression codes that can be used to improve waveform autocorrelation and ambiguity. In particular, Barker codes are bipolar phase codes in which pulses are multiplied by +1 or -1 (or alternate phases between 0° and 180°). Note that the PSLR of a Barker code of length N is dB(N).

[0078] 7A-7D present diagrams illustrating an example of a comparison of pulse and autocorrelation for a pulse and a pulse encoded using a Barker code, according to some embodiments of the present disclosure. In particular, FIG. 7A shows a 4-bin long pulse, and FIG. 7B shows the associated autocorrelation. The PSLR is 4 / 3 or 2.5 dB, and the ISLR is 12 / 4 or -9.5 dB. Furthermore, FIG. 7C shows a Barker-coded pulse B4=[0 0 π 0], and FIG. 7D shows the associated autocorrelation. The PSLR is 4 / 1 or 12 dB, and the ISLR is 4 / 4 or 0 dB.

[0079] However, only nine Barker codes are known: lengths 2, 3, 4, 5, 7, 11, and 13. These Barker codes are summarized in Table 1.

[0080] [Table 1]

[0081] It is possible to generate nested Barker codes of other lengths by applying the Kronecker product to pairs of optimal Barker codes. For example,

[0082]

number

[0083] or

[0084]

number

[0085] is. Note that nested Barker codes are not optimal (they have a PSLR less than N / 1). In some embodiments, Barker codes and / or nested Barker codes may be used in circuit techniques.

[0086] Next, we consider the example of Doppler code multiplexing in K transmission circuits. In the example without Doppler code multiplexing, K can be 4 and n T can be {0,2,6,14}, and Δn T can be {2,4,8,18} (which is unique), and M can be 32 chirps (f D,max may be bin + 16), there may be a single slow target (f D0 (f may be bin + 2). The resulting Doppler spectrum is shown in FIG. 8, which provides a diagram illustrating an example of a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a slow target according to some embodiments of the present disclosure. Note that the target may appear in four bins. The correct Doppler shift is f D (1)=(2+0)·f D,res <f D,max In addition, there are three ghosts D (2)=(2+2)·f D,res <f D,max , f D (3)=(2+6)·f D,res <f D,max , and f D (4)=(2+14)·f D,res <f D,max is possible.

[0087] In a second example that does not use Doppler code multiplexing, K can be 4 and n T can be {0,2,6,14}, and Δn T can be {2,4,8,18} (which is unique), and M can be 32 chirps (f D,maxmay be bin + 16), there may be a single high-speed target (f D0 (f may be bin + 7). The resulting Doppler spectrum is shown in FIG. 9, which provides a diagram illustrating an example of a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target in accordance with some embodiments of the present disclosure. Note that the target may appear in four bins. The correct Doppler shift is f D (1)=(7+0)·f D,res <f D,max In addition, there are three possible ghosts. In particular, there are two unfolded ghosts, f D (2)=(7+2)·f D,res <f D,max , and f D (3)=(7+6)·f D,res <f D,max Furthermore, there is a possibility of a folded ghost f D (4)=(7+14)·f D,res <f D,max In general, aliasing cannot be a problem.

[0088] In a third example using Doppler code multiplexing, K can be 4 and n T can be {0,2,6,14}, and Δn T can be {2,4,8,18} (which is unique), and M can be 32 chirps (f D,max may be bin + 16), there may be a single high-speed target (f D0 (May be bin +7). The resulting Doppler spectrum is shown in Figure 10, which provides a diagram illustrating an example of a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target and encoded using Doppler code multiplexing in accordance with some embodiments of the present disclosure. Note that the actual target bin signal level is now 12 dB higher than the side lobes.

[0089] In a fourth example, without and with Doppler code multiplexing, K can be 4 and n T can be {0,2,6,14}, and Δn T can be {4,4,4} (which is not unique), and M can be 32 chirps (f D,max may be bin + 16), there may be a single high-speed target (f D0 (May be bin +7). The resulting Doppler spectrum is shown in Figures 11A-11B, which provide diagrams illustrating an example of a comparison of the Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target with the Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a high-speed target and coded using Doppler code multiplexing, according to some embodiments of the present disclosure. Note that when Doppler code multiplexing is used in this example, the PSLR is 4 / 3 or 2.5 dB, which is less than 12 dB.

[0090] However, the Doppler map after correlation may appear more complex in real-world scenarios involving noise and multiple targets. This is illustrated in Figures 12 and 13. In particular, Figure 12 presents a diagram illustrating an example of a Doppler spectrum corresponding to a noisy transmission signal reflected from a single target and encoded using Doppler code multiplexing, in accordance with some embodiments of the present disclosure. Furthermore, Figure 13 presents a diagram illustrating an example of a Doppler spectrum corresponding to a transmission signal reflected from multiple targets (including slow and fast targets) and encoded using Doppler code multiplexing, in accordance with some embodiments of the present disclosure.

[0091] As shown in the previous examples, distinguishing actual targets from side lobes can be difficult in some practical scenarios. In some embodiments, this may be addressed using one or more techniques (e.g., within or after the L receiver circuits) to reduce the side lobes and improve the probability of a correct target velocity estimate. For example, in some embodiments, the circuit techniques may include recursive coherent side lobe cancellation. In recursive coherent side lobe cancellation, the strongest current peak in the spectrum may be identified, and P = maximum(|S filt |). The expected (complex) side lobes associated with the strongest identified current peak can then be subtracted from the remainder of the spectrum. These operations can then be repeated M-1 times. Note, however, that when the noise floor is high enough, a noise peak can be mistaken for a target, which can corrupt the spectrum in its (non-existent) side lobes.

[0092] Alternatively, or in addition, in some embodiments, non-coherent sidelobe cancellation may be used. In particular, the filtered Doppler spectrum S D,filt (i D ) the bin containing the side lobe associated with the i-th bin in S th =αN ch max(|S D,filt (i D )|) It is often compared to where N ch is the number of channels (e.g., N when there are K transmission circuits) ch (May be equal to K). Additionally, the constant α can be a multiplier that relaxes the decision threshold in low signal-to-noise scenarios to reduce the false alarm rate (at the expense of a higher false detection rate). |S D,filt (i D )| th When D,filt (i D )=(1+i)·σ​N Note that / 2, where σ N is the average noise in the Doppler spectrum. S D,filt (i D ) instead of zero N The reason for setting σ i = ...

[0093] In some embodiments, α is 0.9 or

[0094]

number

[0095] Furthermore, in some embodiments, the threshold level may be α·N ch FS, where FS is the ADC full-scale (maximum) value. For example, if α is equal to 0.9 and N ch If is equal to 4, the threshold level may be equal to 3.6 FS. The ADC full-scale value for a 12-bit ADC is 2 12 Note that the threshold value can be -1 or 4095. Additionally, in some embodiments, the threshold value can be -80 dBFS (decibels relative to full scale).

[0096] In some embodiments, inter-frame processing may be used to reduce or eliminate side lobes. In particular, the placement of side lobes may be adjusted to n between frames. T , which may facilitate sidelobe identification and subsequent reduction or elimination. However, inter-frame processing can be slow and may significantly increase the overhead of a digital signal processing (DSP) architecture.

[0097] 14A-14C present diagrams illustrating an example of a comparison of two Doppler spectra for a received signal corresponding to a transmitted signal reflected from a target and coded using Doppler code multiplexing, and a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target with sidelobe cancellation and coded using Doppler code multiplexing, in accordance with some embodiments of the present disclosure. In particular, FIG. 14A illustrates a comparison of two Doppler spectra for a received signal corresponding to a transmitted signal reflected from a target in frame 1 and coded using Doppler code multiplexing, in accordance with some embodiments of the present disclosure. T 14B shows the Doppler spectrum for the received signal corresponding to the transmitted signal, encoded using Doppler code multiplexing when n = {0, 2, 6, 14}. T 14C shows the Doppler spectrum for a received signal corresponding to a transmitted signal, encoded using Doppler code multiplexing, when .times. ...

[0098] In some embodiments of the circuit technology, transmit and / or receive beamforming is used. In particular, to steer a transmit beam at a general angle θ, a vector n T Each element of may be multiplied by a complex weight,

[0099]

number

[0100] where S D,filt is the filtered Doppler spectrum, and (i D ,θ) is the Doppler bin index, and n T,k is the kth transmission Doppler shift, and ω k is a complex weight vector. Alternatively, this expression can be written in the more compact form

[0101]

number

[0102] It can be expressed as where:

[0103]

number

[0104] may be a zero-padded representation of ω(θ).

[0105] Although the above description has illustrated circuit techniques involving Doppler code multiplexing exclusively in K transmission circuits (or transmitters), these circuit techniques may alternatively or additionally be implemented in L reception circuits (or receivers). The Doppler code multiplexing in the receiver may be the same as that implemented in the transmitter. Alternatively, the transmitter may use a first Doppler code multiplexing that is different from the second Doppler code multiplexing used in the receiver. However, the principle of Doppler code multiplexing in the receiver may be similar to that used in the transmitter. In particular, the received signal in the lth reception front end (e.g., downconverter) may be divided into Doppler bin n R,l between M chirps in a frame to shift by

[0106]

number

[0107] A constant phase shift of .gtoreq. .gtoreq.

[0108]

number

[0109] Similarly, in some embodiments, the beam at receive angle θ is

[0110]

number

[0111] It may be formed as where S D,filt is the filtered Doppler spectrum, and (i D ,θ) is the Doppler bin index, and n R,l is the l-th received Doppler shift, and ω k is a complex weight vector.

[0112] These circuit techniques may be implemented using one or more integrated circuits in the transmitter, receiver, or both. For example, Figure 15 presents a block diagram illustrating an example of a first integrated circuit 1500 according to some embodiments of the present disclosure. This first integrated circuit may include K transmit circuits 1510 that implement at least a portion of the circuit techniques.

[0113] 16 presents a block diagram illustrating an example of a second integrated circuit 1600 according to some embodiments of the present disclosure. This second integrated circuit may include L receiver circuits 1610 that implement at least a portion of the circuit technique.

[0114] In some embodiments, these circuit techniques may be implemented, for example, on opposite sides of a link in a system, as shown in Figure 17, which presents a block diagram illustrating an example of a system 1700 comprising a first integrated circuit 1510 and a second integrated circuit 1610 according to some embodiments of the present disclosure.

[0115] Furthermore, in some embodiments, the circuit techniques for the transmitter and receiver are implemented in an integrated circuit. This is shown in FIG. 18, which presents a block diagram illustrating an example of an integrated circuit 1800 according to some embodiments of the present disclosure. In this integrated circuit, the target reflection of the kth transit circuit waveform received by the lth front-end receiver circuit is represented by the nested symbol n kl =n T,k +n R,l This results in the following Doppler shift: Δf D (k,l)=(n T,k +n R,l )·f D,res = n k,l f D,res )

[0116] When nested transmit and receive Doppler code multiplexing is used, the spatial Doppler matched filter operation of the nested transmit and receive MIMO system is

[0117]

number

[0118] It can be expressed as: However, n k,l Since is a nested code, it may have some non-unique elements. For example, the uniquely spaced transmit and receive Doppler patterns n T = {0,12,28,48} and n R ={0,2,5,9}. The resulting Doppler spectrum and ambiguity function are shown in Figures 19A-19B, which provide diagrams illustrating an example of a Doppler spectrum and corresponding ambiguity function for a received signal corresponding to a transmitted signal reflected from a single target with nested transmit and receive Doppler code multiplexing according to some embodiments of the present disclosure.

[0119] In some embodiments, the Doppler ambiguity function is n T and n R The matched filter of Barker code B T and B R (Note that Barker codes can be used in circuit techniques instead of FMCW.) The operation of the Doppler spatial matched filter is

[0120]

number

[0121] It can be expressed as: In some embodiments, different or nested Barker codes are used for different chirps, for different transmit circuits, and / or for different receive circuits.

[0122] 20A-20B present diagrams illustrating an example of a comparison between an ambiguity function corresponding to a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and encoded using Doppler code multiplexing in the transmit and receive circuits, and an ambiguity function corresponding to a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and encoded using Doppler code multiplexing and a Barker code in the transmit and receive circuits, in accordance with some embodiments of the present disclosure. In particular, FIGS. 20A-20B illustrate a comparison of a Doppler spectrum for a received signal corresponding to a transmitted signal reflected from a target and encoded using Doppler code multiplexing and a Barker code in the transmit and receive circuits, in accordance with some embodiments of the present disclosure.

[0123]

number

[0124] n without and with T = {0,12,28,48} and n R= {0,2,5,9}. Figure 20A shows the resulting ambiguity function without pulse compression. The PSLR is 4.1 dB and the ISLR is -23.5 dB. Furthermore, Figure 20B shows the results for the nested Barker code B 44 The resulting ambiguity function is shown in Figure 1. The PSLR is 12.0 dB and the ISLR is -14.4 dB.

[0125] Next, we will describe method embodiments. Figure 21 presents a flow diagram illustrating one example of a method 2100 for communicating coded signals, which may be performed by one or more integrated circuits. During operation, the one or more integrated circuits may be configured to output K transmit signals using K transmit circuits (Operation 2110), where K is a non-zero integer, and the K transmit signals are coded using a first Doppler code multiplexing. Additionally, the one or more integrated circuits may be configured to provide L receive signals using L receive circuits (Operation 2112), where L is a non-zero integer, and the L receive signals are coded using a second Doppler code multiplexing.

[0126] There may be additional or fewer operations in some embodiments of method 2100. Additionally, the order of the operations may be changed and / or two or more operations may be combined into a single operation.

[0127] The disclosed integrated circuits and circuit techniques can be (or can be included in) any electronic device or system. For example, the electronic device can include, for example, a mobile phone or smartphone, a tablet computer, a laptop computer, a notebook computer, a personal or desktop computer, a netbook computer, a media player device, an e-book device, a MiFi® device, a smart watch, a wearable computing device, a portable computing device, a consumer electronic device, an access point, a router, a switch, communications equipment, test equipment, a vehicle, a watercraft, an aircraft, an automobile, a truck, a bus, a motorcycle, manufacturing equipment, agricultural equipment, construction equipment, or another type of electronic device.

[0128] Although particular components are used to describe embodiments of an integrated circuit and / or an integrated circuit comprising an integrated circuit, in alternative embodiments, different components and / or subsystems may be present within the integrated circuit and / or the integrated circuit comprising the integrated circuit. Thus, embodiments of an integrated circuit and / or an integrated circuit comprising an integrated circuit may include fewer components, additional components, or different components, two or more components may be combined into a single component, a single component may be separated into two or more components, one or more positions of one or more components may be changed, and / or there may be different types of components.

[0129] Furthermore, the circuits and components in embodiments of integrated circuits and / or integrated circuits comprising integrated circuits may be implemented using any combination of analog and / or digital circuits, including bipolar, PMOS, and / or NMOS gates or transistors. Furthermore, signals in these embodiments may include digital signals having more or less discrete values ​​and / or analog signals having continuous values. Additionally, components and circuits may be single-ended or differential, and power supplies may be unipolar or bipolar. It should be noted that electrical couplings or connections in the previously described embodiments may be direct or indirect. In the previously described embodiments, a single line corresponding to a route may refer to one or more single lines or routes.

[0130] As previously mentioned, at least one integrated circuit may implement some or all of the functionality of the circuit technology, and this integrated circuit may include hardware and / or software mechanisms used to implement the functionality associated with the circuit technology.

[0131] In some embodiments, the output of a process for designing an integrated circuit, or a portion of an integrated circuit, including one or more of the circuits described herein may be a computer-readable medium, such as, for example, a magnetic tape or an optical or magnetic disk. The computer-readable medium may be encoded with data structures or other information describing a circuit that may be physically instantiated in the integrated circuit or as part of the integrated circuit. Although various formats may be used for such encoding, these data structures are commonly described in Caltech Intermediate Format (CIF), Calma GDS II Stream Format (GDSII), Electronic Design Interchange Format (EDIF), Open Access (OA), or Open Artwork System Interchange Standard (OASIS). One skilled in the art of integrated circuit design can develop such data structures from schematic diagrams and corresponding descriptions of the type detailed above and encode the data structures on a computer-readable medium. One skilled in the art of integrated circuit fabrication can use such encoded data to fabricate integrated circuits including one or more of the circuits described herein.

[0132] Although some of the operations in the previously described embodiments have been implemented in hardware or software, in general, the operations in the previously described embodiments may be implemented in a wide variety of configurations and architectures. Thus, some or all of the operations in the previously described embodiments may be performed in hardware, software, or both. For example, at least some of the operations in the circuitry may be implemented using program instructions executed by a processor or in firmware within an integrated circuit.

[0133] Furthermore, although example values ​​are provided in the foregoing description, other embodiments may use different values, and as a result, the values ​​provided are not intended to be limiting.

[0134] In the preceding description, we refer to "some embodiments." Note that "some embodiments" describes a subset of all possible embodiments, but does not always specify the same subset of embodiments.

[0135] The preceding description is intended to enable any person skilled in the art to make and use the present disclosure and is provided in the context of a particular application and its requirements. Moreover, the foregoing descriptions of embodiments of the present disclosure have been presented for purposes of illustration and description only. They are not intended to be exhaustive or to limit the disclosure to the forms disclosed. Accordingly, many modifications and variations will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit or scope of the present disclosure. Additionally, the description of the embodiments set forth above is not intended to limit the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. [Explanation of symbols]

[0136] 110 vehicles 112 Antennas for Short-Range Sensing 114 Antennas for Mid-Range Sensing 116 Antennas for Long-Range Sensing 118 Antennas for Short-Range Sensing 120 Antenna for Mid-Range Sensing 122 Antennas for Short-Range Sensing 205 Radar Array Controller 210 Electronic Control Unit (ECU) 212 Sensors 214 Radar Array Controller 216 Turn signal actuator 218 Steering Actuator 220 Braking Actuator 222 Throttle Actuator 224 User Interface 310 Radar System 312 Transmission Antenna 314 Reflector or Target 316 Transmission Signal 318 Received Signal 320 receiving antenna 410 Radar Transceiver Circuit 412 Carrier Signal (Chirp) Generator 414 Phase shifter 416 Amplifier 418 Low Noise Amplifier (LNA) 420 Mixer 422 Broadband (BB) filter 424 Analog-to-Digital Converter (ADC) 426 processor 1500 First Integrated Circuit 1510 Transmission Circuit 1600 Second Integrated Circuit 1610 Receiver Circuit 1700 System 2100 method

Claims

1. 1. An integrated circuit comprising: K transmit circuits configured to output K transmit signals, where K is a non-zero integer, and the K transmit signals are encoded using a first Doppler code multiplexing; L receive circuits configured to provide L receive signals, where L is a non-zero integer, and where the L receive signals are encoded using second Doppler code multiplexing.

2. The integrated circuit of claim 1 , wherein the L received signals correspond to the K transmitted signals.

3. 10. The integrated circuit of claim 1, wherein the first Doppler code multiplexing, the second Doppler code multiplexing, or both, are different from Doppler division multiplexing.

4. a given transmission signal among the K transmission signals includes M chirps in a frame, where M is a non-zero integer; 2. The integrated circuit of claim 1, wherein a given received signal among the L received signals includes the M chirps in the frame.

5. During the first Doppler code multiplexing, the kth transmission signal among the K transmission signals is assigned to bin n k are selectively Doppler shifted by Bin n k 2. The integrated circuit of claim 1, wherein the selective Doppler shift is selectively applied among M chirps within a frame in the kth transmission signal.

6. During the second Doppler code multiplexing, the l-th received signal among the L received signals is assigned to bin n l are selectively Doppler shifted by Bin n l 2. The integrated circuit of claim 1, wherein the selective Doppler shift is selectively applied among M chirps within a frame in the l-th received signal.

7. During the first Doppler code multiplexing, the Doppler shifted n k phase shifts corresponding to bins are selectively applied among the M chirps in a frame in the kth transmitted signal; The integrated circuit of claim 1 , wherein the differences between the phase shifts selectively applied to different pairs of transmit signals in the K transmit signals are different.

8. During the second Doppler code multiplexing, the Doppler shifted n l phase shifts corresponding to bins are selectively applied among M chirps in a frame in the l-th received signal; The integrated circuit of claim 1 , wherein the differences between the phase shifts selectively applied to different pairs of received signals among the L received signals are different.

9. the integrated circuit is configured to calculate a Doppler spectrum using the L received signals and a matched filter corresponding to the first Doppler code multiplexing, the second Doppler code multiplexing, or both; The integrated circuit of claim 1 , wherein the Doppler spectrum has a peak-to-sidelobe ratio (PSLR) greater than a predefined value.

10. The integrated circuit of claim 1 , wherein L is different from K.

11. 2. The integrated circuit of claim 1, wherein the first Doppler code multiplexing is different from the second Doppler code multiplexing.

12. the K transmit signals, the L receive signals, or both, are encoded using one or more bipolar phase codes; a given bipolar phase code among the one or more bipolar phase codes changes the phase of a given transmit signal among the K transmit signals, a given receive signal among the L receive signals, or both, within a given frame containing M chirps; 2. The integrated circuit of claim 1, wherein M is a non-zero integer.

13. 13. The integrated circuit of claim 12, wherein the one or more bipolar phase codes include a Barker code or a nested Barker code.

14. 13. The integrated circuit of claim 12, wherein a first bipolar phase code in the one or more bipolar phase codes used to encode the K transmit signals is different from a second bipolar phase code in the one or more bipolar phase codes used to encode the L receive signals.

15. the integrated circuit is configured to perform a sidelobe cancellation technique; The integrated circuit of claim 1 , wherein the sidelobe cancellation technique includes recursive coherent sidelobe cancellation, non-coherent sidelobe cancellation, or inter-frame processing.

16. 10. The integrated circuit of claim 1, wherein the K transmit circuits are configured to perform beamforming of the K transmit signals, the L receive circuits are configured to perform beamforming of the L receive signals, or both.

17. 2. The integrated circuit of claim 1, wherein the L receiver circuits are configured to encode the L received signals using the second Doppler code multiplexing when downconverting the L received signals to baseband or to an intermediate carrier frequency different from one or more carrier frequencies of the K transmit signals.

18. 1. An electronic device comprising: An integrated circuit, the integrated circuit comprising: K transmit circuits configured to output K transmit signals, where K is a non-zero integer, and the K transmit signals are encoded using a first Doppler code multiplexing; and L receiver circuits configured to provide L receive signals, where L is a non-zero integer, and where the L receive signals are encoded using a second Doppler code multiplexing.

19. 20. The electronic device of claim 18, wherein the electronic device comprises a vehicle.

20. 1. A method for communicating a coded signal by communication, comprising: By integrated circuits, using K transmit circuits to output K transmit signals, where K is a non-zero integer, and the K transmit signals are encoded using a first Doppler code multiplexing; and using L receive circuits to provide L receive signals, where L is a non-zero integer, the L receive signals being encoded using second Doppler code multiplexing.

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