Synchronization of multiple mmWave devices

Abstract

The present disclosure relates to synchronization of multiple millimeter-wave devices. For example, a method includes: receiving a global trigger with a first millimeter-wave radar; receiving a global trigger with a second millimeter-wave radar; generating a first internal trigger for the first millimeter-wave radar after a first offset duration from the global trigger; generating a second internal trigger for the second millimeter-wave radar after a second offset duration from the global trigger; starting transmission of a first millimeter-wave radar signal with the first millimeter-wave radar based on the first internal trigger; and starting transmission of a second millimeter-wave radar signal with the second millimeter-wave radar based on the second internal trigger, wherein the second offset duration is different from the first offset duration, and wherein the first and second millimeter-wave radar signals are transmitted sequentially so as not to exhibit temporal overlap.

Description

Technical Field

[0001] The present invention relates generally to electronic systems and methods and, in particular embodiments, to synchronization of multiple millimeter wave (mmWave) devices. Background Art

[0002] Applications operating at millimeter-wave frequencies have gained significant interest over the past few years due to the rapid advancement of low-cost semiconductor technologies such as silicon-germanium (SiGe) and fine-geometry complementary metal-oxide-semiconductor (CMOS) processes. The availability of high-speed bipolar and metal-oxide-semiconductor (MOS) transistors has led to a growing demand for integrated circuits for millimeter-wave applications operating at 24 GHz, 60 GHz, 77 GHz, 80 GHz, and above 100 GHz. These applications include, for example, automotive radar systems and multi-gigabit communication systems.

[0003] In some radar systems, the distance between the radar and the target is determined by transmitting a frequency modulated signal, receiving the reflection of the frequency modulated signal (also called an echo), and determining the distance based on the time delay, phase and / or frequency difference between the transmission and reception of the frequency modulated signal. Therefore, some radar systems include a transmitting antenna for transmitting radio frequency (RF) signals, a receiving antenna for receiving RF, and associated RF circuits for generating the transmit signal and receiving the RF signal. In some cases, multiple antennas can be used to implement directional beams using phased array technology. Multiple-input multiple-output (MIMO) configurations with multiple chipsets can also be used to perform coherent and non-coherent signal processing. Summary of the Invention

[0004] According to one embodiment, a method includes: receiving a global trigger using a first millimeter-wave radar; receiving a global trigger using a second millimeter-wave radar; generating a first internal trigger for the first millimeter-wave radar after a first offset duration from the global trigger; generating a second internal trigger for the second millimeter-wave radar after a second offset duration from the global trigger; based on the first internal trigger, starting to transmit a first millimeter-wave radar signal using the first millimeter-wave radar; and based on the second internal trigger, starting to transmit a second millimeter-wave radar signal using the second millimeter-wave radar, wherein the second offset duration is different from the first offset duration, and wherein the first millimeter-wave radar signal and the second millimeter-wave radar signal are transmitted sequentially so as not to exhibit time overlap.

[0005] According to one embodiment, a system includes an application processor and first and second millimeter-wave radars. The application processor is configured to generate a global trigger. The first millimeter-wave radar includes: a first timer configured to generate a first internal trigger after a first offset duration from the global trigger; a first millimeter-wave radar sensor circuit; and a first controller configured to use the first millimeter-wave radar sensor circuit to generate a first millimeter-wave radar signal based on the first internal trigger. The second millimeter-wave radar includes: a second timer configured to generate a second internal trigger after a second offset duration from the global trigger; a second millimeter-wave radar sensor circuit; and a second controller configured to use the second millimeter-wave radar sensor circuit to generate a second millimeter-wave radar signal based on the second internal trigger, wherein the second offset duration is different from the first offset duration, such that the first millimeter-wave radar signal and the second millimeter-wave radar signal are transmitted sequentially and without temporal overlap.

[0006] According to one embodiment, a system includes an application processor and first and second millimeter-wave radars. The application processor is configured to generate a global trigger. The first millimeter-wave radar includes: a first trigger terminal configured to receive a global trigger; a first timer configured to generate a first internal trigger after a first offset duration from the global trigger; a first millimeter-wave radar sensor circuit; and a first controller configured to use the first millimeter-wave radar sensor circuit to generate a first millimeter-wave radar signal based on the first internal trigger. The second millimeter-wave radar includes: a second trigger terminal configured to receive a global trigger; a second timer configured to generate a second internal trigger after a second offset duration from the global trigger; a second millimeter-wave radar sensor circuit; and a second controller configured to use the second millimeter-wave radar sensor circuit to generate a second millimeter-wave radar signal based on the second internal trigger, wherein the second offset duration is different from the first offset duration, so that the first millimeter-wave radar signal and the second millimeter-wave radar signal are transmitted sequentially and without time overlap. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more fully understand the present invention and its advantages, the following description is now made with reference to the accompanying drawings, in which:

[0008] Figure 1 A flowchart of an embodiment method for synchronizing multiple millimeter-wave radars according to an embodiment of the present invention is shown;

[0009] Figure 2 shows the waveform of a signal of a millimeter wave radar system according to an embodiment of the present invention;

[0010] Figure 3 The embodiment of the present invention is shown Figure 2 Chirp emission and power amplifier status of millimeter-wave radar;

[0011] Figure 4 A flowchart illustrating an embodiment method for programming and synchronizing multiple millimeter wave radars according to an embodiment of the present invention is shown; and

[0012] Figure 5 and Figure 6 FIG. 1 is a schematic diagram of a millimeter wave system according to an embodiment of the present invention.

[0013] Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated.The figures are drawn to clearly illustrate the relevant aspects of the preferred embodiments and are not necessarily drawn to scale. DETAILED DESCRIPTION

[0014] The making and using of the disclosed embodiments are discussed in detail below. However, it should be understood that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention and do not limit the scope of the invention.

[0015] The following description shows various specific details to provide a deeper understanding of several example embodiments according to the description. The embodiments can be obtained without one or more specific details, or can be obtained using other methods, components, materials, etc. In other cases, known structures, materials, or operations are not shown or described in detail so as not to obscure different aspects of the embodiments. References to "one embodiment" in this specification indicate that a particular configuration, structure, or feature described with respect to that embodiment is included in at least one embodiment. Therefore, phrases such as "in one embodiment" appearing at different points in this specification do not necessarily refer to the same embodiment. In addition, in one or more embodiments, specific forms, structures, or features may be combined in any appropriate manner.

[0016] Embodiments of the present invention will be described in the specific context of circuits and methods for synchronizing multiple millimeter wave devices, such as millimeter wave radars. Embodiments of the present invention may be used to synchronize other types of millimeter wave devices, such as 5G communication devices, for example, operating in a multiple-input multiple-output (MIMO) configuration. Some embodiments may be used to synchronize other types of devices that do not operate within the millimeter wave frequency range.

[0017] In one embodiment of the present invention, multiple devices are synchronized using local synchronization circuitry implemented in each of the multiple devices. A global trigger is sent to each of the multiple devices, rather than each device using a dedicated trigger. Timing in each device is based on the local synchronization circuitry and the global trigger.

[0018] In many applications, multiple devices rely on synchronization mechanisms during normal operation. For example, in some applications, multiple millimeter-wave radars located in different parts of a printed circuit board (PCB) rely on synchronization mechanisms, for example to avoid radio frequency (RF) interference from transmitted chirps and / or to perform functions such as beamforming. Traditionally, the application processor synchronizes the millimeter-wave radars by sending a dedicated trigger signal to each millimeter-wave radar at the appropriate time using a dedicated line electrically connected to each millimeter-wave radar. In other words, the application processor is responsible for ensuring correct timing.

[0019] In one embodiment of the present invention, local synchronization circuitry implemented in each millimeter-wave radar is used to control the timing of chirps based on a common global trigger. Each local synchronization circuit has a unique time offset that delays the start of the first chirp by a unique offset duration. In some embodiments, the same finite state machine (FSM) is used in each radar to control the timing between chirps, the duration of each chirp, and the start of the first chirp, where the delay imposed by each FSM is, for example, programmed to be unique for each millimeter-wave radar.

[0020] Figure 1 A flow chart of an exemplary method 100 for synchronizing multiple millimeter-wave radars according to an embodiment of the present invention is shown.

[0021] During step 102, a global trigger is sent to the set of millimeter-wave radars, for example, by an application processor. In some embodiments, the global trigger is sent using a trigger line (e.g., a PCB trace) connected to a general-purpose I / O (GPIO) terminal of the application processor, where the trigger line is connected to the trigger terminal of each millimeter-wave radar. In some embodiments, the global trigger is sent using a communication interface such as an inter-integrated circuit (I2C) or a serial peripheral interface (SPI). For example, in some embodiments, the global trigger can be sent using an SPI broadcast mode, such as described in a co-pending U.S. patent associated with attorney docket number INF 2019 P 56018 US, filed on the same day as this application, entitled "SPI Broadcast Mode," which is incorporated herein by reference.

[0022] During step 104, each mmWave radar receives a global trigger and, based on the global trigger, starts a corresponding local timer. In some embodiments, the local timers are implemented using digital counters. For example, in some embodiments, each local counter counts to a predetermined count, where the predetermined count is different for each mmWave radar in the set. In some embodiments, each predetermined count is programmed by an application processor using, for example, SPI.

[0023] During step 106, when the corresponding local timer expires (e.g., when the digital counter reaches a predetermined count), the corresponding millimeter-wave radar begins transmitting (e.g., sequentially) radar signals (such as linear frequency modulation), for example, according to the corresponding finite state machine of each millimeter-wave radar. In some embodiments, because each local timer is configured to expire at a different time, the linear frequency modulation transmitted (e.g., sequentially) from each millimeter-wave radar occurs at a different time, thereby advantageously allowing for avoiding RF interference and allowing time division multiplexing (TDM) of the linear frequency modulation from each millimeter-wave radar and allowing operations such as beamforming, while using a single global trigger.

[0024] Figure 2 A waveform 200 of a signal of a millimeter wave radar system according to an embodiment of the present invention is shown. Figure 2 The waveform 200 corresponds to an implementation of the method 100 according to an embodiment that uses the SPI broadcast mode and includes an application processor and first and second millimeter wave radars.

[0025] Waveform 200 shows an SPI clock signal SCLK, an SPI master output slave input (MOSI) signal MOSI, and SPI chip select (CS) signals CS1 and CS2 (corresponding to the first and second millimeter wave radars).

[0026] like Figure 2 As shown, a global trigger is sent to the first and second millimeter-wave radars simultaneously using an SPI write command (step 102). At time t1, the first and second millimeter-wave radars simultaneously receive the global trigger.

[0027] Once the global trigger is received, the internal frame start signals are asserted (or "activated") (transitioned to an active state, in this case to a logic 1) to indicate the start of the transmit process. As shown, each of the internal frame start signals FRAME_START1 and FRAME_START2 is asserted simultaneously with the receipt of the global trigger. In some embodiments, there may be a delay between the receipt of the global trigger and the assertion of the internal frame start signals.

[0028] Each internal frame start signal (FRAME_START1 and FRAME_START2) starts a corresponding local counter (step 104), which counts up to a predetermined count. Each corresponding count is unique so that each mmWave radar exhibits a corresponding offset duration (t) from the start of receipt of the global trigger (starting from t1). offset1 and t offset2 ) is unique.

[0029] After the corresponding offset duration (t offset1 and toffset2 ), each millimeter wave radar starts transmitting a sequence of linear frequency modulations (CHIRPS1 and CHIRPS2) (step 106). Figure 2 As shown, the transmissions of the first (CHIRPS1) and second (CHIRPS2) chirp sequences (illustrated by the assertion of signals CHIRPS1 and CHIRPS2, respectively) do not overlap.

[0030] Figure 3 The embodiment of the present invention is shown Figure 2 Chirp transmission and power amplifier status of millimeter-wave radar. Figure 3 The waveform 300 corresponds to an embodiment of the method 100, such as Figure 2 shown.

[0031] like Figure 3 As shown, the sequences of linear frequency modulations from the first and second millimeter wave radars (CHIRPS1 and CHIRPS2, respectively) do not overlap. Figure 3 As shown, the activation times of the corresponding power amplifiers (PowerAmp1 and PowerAmp2) of the first and second millimeter-wave radars do not overlap.

[0032] By avoiding overlap in the chirp and power amplifier activation times, some embodiments advantageously avoid RF interference between transmitted radar signals of the millimeter wave radar. Some embodiments advantageously avoid RF interference without burdening the application processor with ensuring correct timing.

[0033] Additional advantages of some embodiments include reducing the risk of not ensuring correct timing, for example due to unexpected interrupts that may consume processing resources of, for example, an application processor.

[0034] Figure 2 and Figure 3 An embodiment including two millimeter wave radars and one application processor is shown. It should be understood that more than two millimeter wave radars can be used, such as n, where n is a positive integer greater than 2, such as 4, 5, 10, 16, 32 or more, and the corresponding offset duration (t offset1 , t offset2 ,…,t offsetn ) so that each corresponding linear frequency modulation sequence (CHIRPS1, CHIRPS2, ..., CHIRPS n ) have no overlap.

[0035] Figure 4 A flow chart of an embodiment method 400 for programming and synchronizing multiple millimeter-wave radars according to an embodiment of the present invention is shown.

[0036] During step 402, a first millimeter-wave radar is programmed with a first time offset threshold, for example, via a digital communication bus (such as via SPI). During step 404, a second millimeter-wave radar is programmed with a second time offset threshold, for example, via a digital communication bus (such as via SPI).

[0037] In some embodiments, the programming of the first time offset threshold is performed, for example, by an application processor (e.g., via SPI). In some embodiments, the programming of the first time offset threshold is performed, for example, by automatic test equipment (ATE) during production testing of the millimeter wave radar.

[0038] For example, as referenced Figure 1 As described, steps 102 , 104 , and 106 may be performed.

[0039] Figure 5 Schematic diagram of a millimeter wave system 500 according to an embodiment of the present invention is shown. Millimeter wave system 500 includes an application processor 512 and millimeter wave radars 514 and 518. Some embodiments may include more than two millimeter wave radars, such as 3, 10, 64, or more.

[0040] During normal operation, the application processor 512 configures the first and second time offset thresholds in the corresponding registers 506 of the millimeter wave radars 514 and 518 (steps 402 and 404), wherein the first time offset threshold is different from the second time offset threshold. In some embodiments, the application processor 512 may also configure other parameters (e.g., Figure 5 Other registers not shown) such as the distance between linear FM, the duration of the linear FM, the start and end frequencies of the linear FM, etc. However, in general, the other parameters programmed can be the same for all millimeter wave radars.

[0041] After configuring the first and second time offset thresholds, the application processor 512 sends a global trigger to the mmWave radars 514 and 518 using, for example, the SPI bus 510 (step 102). For example, in some embodiments, the application processor 512 sends the global trigger using the SPI broadcast mode. In other embodiments, the global trigger can be sent in other ways, such as by using a GPIO of the application processor 512 coupled to both the mmWave radars 514 and 518.

[0042] When receiving the global trigger, each millimeter-wave radar 514 and 518 starts its corresponding local timer 522. Each local timer is configured to generate a local trigger signal CHIRPS_TRIGGER when its corresponding time offset threshold is reached.

[0043] The local trigger signal then causes the corresponding controller 530 to begin transmitting (eg, sequentially) linear frequency modulation (eg, as shown in FIG. 5 ) using the corresponding millimeter wave radar sensor circuit 536. Figure 3 and Figure 4 shown).

[0044] In some embodiments, since each local trigger CHIRPS_TRIGGER depends on the corresponding data programmed in the corresponding register 506, the controller 530 can have the same hardware for the mmWave radars 514 and 518 while achieving non-overlapping linear frequency modulation sequences when using a single global trigger, thereby advantageously relieving the application processor 512 of the task of maintaining proper timing for the mmWave radars 514 and 518.

[0045] The millimeter wave radar system may be implemented, for example, in a printed circuit board (PCB), where SPI bus 510 includes PCB traces coupling application processor 512 with millimeter wave radars 514 and 518. In some embodiments, millimeter wave radars 514 and 518 have the same hardware.

[0046] SPI master 502 and SPI slave 504 can be implemented in any manner known in the art. For example, SPI slave 504 can be implemented without supporting SPI broadcast mode. In such an embodiment, each of millimeter-wave radars 514 and 518 can include a trigger terminal (not shown) coupled to a global trigger terminal of application processor 512 (not shown). In some embodiments, SPI slave 504 can implement SPI broadcast mode.

[0047] Timer 522 can be implemented in any manner known in the art. For example, in some embodiments, timer 522 can be implemented using a digital counter (such as a digital up-counter) that counts up to a time offset threshold stored in register 506 upon receiving a frame start signal. For example, other embodiments can be implemented using a digital down-counter or a digital up / down counter. Other implementations are also possible.

[0048] like Figure 5 As shown, each of millimeter wave radars 514 and 518 includes an SPI slave 504, a controller 530, a millimeter wave radar sensor circuit 536, a register 506, and a timer 522. Each of millimeter wave radars 514 and 518 is configured to perform radar functions, such as target detection and tracking. Radar functions such as target detection and tracking can be performed in any manner known in the art.

[0049] In some embodiments, some or all radar operations may be performed in collaboration with the application processor 512. For example, in some embodiments, the millimeter wave radars 514 and 518 may collaborate with the application processor 512 to perform beamforming. Beamforming may be performed in any manner known in the art. In some embodiments, the millimeter wave radars 514 and 518 may collaborate with the application processor 512 to transmit linear frequency modulation in such a manner as to implement time division multiplexing (TDM). For example, in some embodiments, when (e.g., known) delays are taken into account, raw data from different millimeter wave radars (e.g., 514 and 518) may be used for TDM MIMO. Other radar functions are also possible.

[0050] Millimeter wave radar sensor circuit 536 is configured to transmit and receive radar signals, such as linear frequency modulation. In some embodiments, millimeter wave radar sensor circuit 536 can be implemented as a frequency modulated continuous wave (FMCW) sensor.

[0051] The millimeter wave radar sensor circuit 536 can be implemented in any manner known in the art. For example, in some embodiments, the millimeter wave radar sensor circuit includes a front-end RF circuit 538 and a mixed signal circuit 546.

[0052] RF circuitry 538 is configured to transmit a signal (e.g., a chirp) toward a target and receive an echo (i.e., reflected) signal from a target in its field of view using one or more antennas (not shown). RF circuitry 538 includes transmitter circuitry 540 and receiver circuitry 542.

[0053] Transmitter circuitry 540 and receiver circuitry 542 may be implemented in any manner known in the art. For example, in some embodiments, transmitter circuitry 540 includes a power amplifier that amplifies chirps that are transmitted via one or more antennas (not shown).

[0054] The mixed signal circuit 546 is configured to control the RF circuit 538 to transmit a signal (eg, chirp) and receive an echo signal. The mixed signal circuit 546 is also configured to convert the RF signal into a digital signal and then transmit the digital signal to the controller 530.

[0055] The mixed signal circuit 546 can be implemented in any manner known in the art. For example, in some embodiments, the mixed signal circuit 546 includes one or more bandpass filters (BPFs), lowpass filters (LPFs), mixers, low noise amplifiers (LNAs), intermediate frequency (IF) amplifiers, phase-locked loops (PLLs), and analog-to-digital converters (ADCs).

[0056] The controller 530 is configured to process the signals received from the millimeter wave radar sensor circuit 536 and transmit them to the application processor 512 via the SPI bus 510 , for example.

[0057] Controller 530 can be implemented in any manner known in the art, such as a general-purpose controller or processor, an application-specific integrated circuit (ASIC), or any other implementation. Controller 530 generally includes a digital block 532 for general control purposes (e.g., controlling millimeter-wave radar sensor circuit 536) and a signal processing block 534 for processing signals received from millimeter-wave radar sensor circuit 536. Digital block 532 may include a finite state machine (FSM), for example, to control the timing of transmitted chirps. Signal processing block 534 may be implemented using a digital signal processor (DSP).

[0058] In some embodiments, the millimeter wave radar sensor circuit 536, the controller 530, the register 506, the timer 522, and the SPI slave 504 are implemented in the same package. Some embodiments also include one or more antennas (not shown) in the same package. Other embodiments may implement one or more of the millimeter wave radar sensor circuit 536, the controller 530, the register 506, the timer 522, and the SPI slave 504 as discrete components of the millimeter wave radar, for example, coupled to the same PCB. Other embodiments use more than one PCB to implement the millimeter wave system 500. Other implementations are also possible.

[0059] Application processor 512 may be implemented in any manner known in the art, such as a general purpose controller or processor, an ASIC, or any other implementation.

[0060] Figure 6 FIG2 shows a schematic diagram of a millimeter wave system 600 according to an embodiment of the present invention. Millimeter wave system 600 operates in a similar manner to millimeter wave system 500. However, millimeter wave system 600 includes a global trigger line coupled between the GPIO of application processor 512 and millimeter wave radars 514 and 518. For example, the global trigger line can be implemented as a trace on a PCB.

[0061] Example embodiments of the invention are summarized here. Other embodiments may also be understood from the overall description and claims submitted herein.

[0062] Example 1. A method comprising: receiving a global trigger using a first millimeter-wave radar; receiving a global trigger using a second millimeter-wave radar; generating a first internal trigger for the first millimeter-wave radar after a first offset duration from the global trigger; generating a second internal trigger for the second millimeter-wave radar after a second offset duration from the global trigger; starting to transmit a first millimeter-wave radar signal using the first millimeter-wave radar based on the first internal trigger; and starting to transmit a second millimeter-wave radar signal using the second millimeter-wave radar based on the second internal trigger, wherein the second offset duration is different from the first offset duration, and the first millimeter-wave radar signal and the second millimeter-wave radar signal are transmitted sequentially so as not to display time overlap.

[0063] Example 2. The method of Example 1, further comprising: generating a global trigger using an application processor.

[0064] Example 3. The method of Example 1 or 2 further includes: generating a global trigger using a general-purpose input / output (GPIO) pin of an application processor, wherein the GPIO pin is coupled to the first millimeter-wave radar and the second millimeter-wave radar.

[0065] Example 4. The method of one of Examples 1 to 3, further comprising: generating a global trigger using a master output slave input MOSI line of a serial peripheral interface SPI.

[0066] Example 5. The method of one of Examples 1 to 4, further comprising: programming a first offset duration into the first millimeter-wave radar; and programming a second offset duration into the second millimeter-wave radar.

[0067] Example 6. The method according to one of Examples 1 to 5 further includes: after receiving a global trigger through the first millimeter-wave radar, starting a first digital counter of the first millimeter-wave radar, and generating a first internal trigger when the first count of the first digital counter reaches a first time offset threshold corresponding to the first offset duration; and after receiving a global trigger through the second millimeter-wave radar, starting a second digital counter of the second millimeter-wave radar, and generating a second internal trigger when the second count of the second digital counter reaches a second time offset threshold corresponding to the second offset duration.

[0068] Example 7. The method of one of Examples 1 to 6, wherein the first time offset threshold is stored in a first register of the first millimeter-wave radar, and wherein the second time offset threshold is stored in a second register of the second millimeter-wave radar.

[0069] Example 8. The method of one of Examples 1 to 7, further comprising: programming a first time offset threshold into the first register; and programming a second time offset threshold into the second register.

[0070] Example 9. The method according to one of Examples 1 to 8 further includes: performing beamforming using the first millimeter wave radar and the second millimeter wave radar.

[0071] Example 10. A system comprising: an application processor configured to generate a global trigger; a first millimeter-wave radar comprising: a first timer configured to generate a first internal trigger after a first offset duration from the global trigger; a first millimeter-wave radar sensor circuit; and a first controller configured to use the first millimeter-wave radar sensor circuit to generate a first millimeter-wave radar signal based on the first internal trigger; and a second millimeter-wave radar comprising: a second timer configured to generate a second internal trigger after a second offset duration from the global trigger; a second millimeter-wave radar sensor circuit; and a second controller configured to use the second millimeter-wave radar sensor circuit to generate a second millimeter-wave radar signal based on the second internal trigger, wherein the second offset duration is different from the first offset duration, so that the first millimeter-wave radar signal and the second millimeter-wave radar signal are transmitted sequentially and without time overlap.

[0072] Example 11. The system of Example 10, wherein the first millimeter-wave radar further comprises a first serial peripheral interface (SPI) slave circuit, wherein the second millimeter-wave radar further comprises a second SPI slave circuit, and wherein the application processor comprises an SPI master circuit coupled to the first and second SPI slave circuits via an SPI bus.

[0073] Example 12. The system of example 10 or 11, wherein the application processor is configured to transmit a global trigger to the first and second SPI slave circuits using the SPI bus.

[0074] Example 13. The system of one of Examples 10 to 12, wherein the application processor is configured to: program the first offset duration into the first millimeter-wave radar using the SPI bus; and program the second offset duration into the second millimeter-wave radar using the SPI bus.

[0075] Example 14. The system of one of Examples 10 to 13, further comprising a printed circuit board (PCB) coupled to the application processor and to the first and second millimeter-wave radars, wherein the PCB comprises an SPI bus.

[0076] Example 15. A system according to one of Examples 10 to 14, wherein the first timer includes a first counter, wherein the first millimeter-wave radar also includes a first register configured to store a first time offset threshold corresponding to the first offset duration, wherein the second timer includes a second counter, and wherein the second millimeter-wave radar also includes a second register configured to store a second time offset threshold corresponding to the second offset duration.

[0077] Example 16. A system according to one of Examples 10 to 15, wherein the first counter is configured to start counting up after receiving a global trigger and to generate a first internal trigger when a first count of the first counter reaches a first time offset threshold, and wherein the second counter is configured to start counting up after receiving a global trigger and to generate a second internal trigger when a second count of the second counter reaches a second time offset threshold.

[0078] Example 17. The system of any of Examples 10 to 16, wherein the application processor is configured to send the global trigger using a GPIO terminal coupled to respective trigger terminals of the first and second millimeter-wave radars.

[0079] Example 18. A system comprising: an application processor configured to generate a global trigger; a first millimeter-wave radar comprising: a first trigger terminal configured to receive the global trigger; a first timer configured to generate a first internal trigger after a first offset duration from the global trigger; a first millimeter-wave radar sensor circuit; and a first controller configured to use the first millimeter-wave radar sensor circuit to generate a first millimeter-wave radar signal based on the first internal trigger; and a second millimeter-wave radar comprising: a second trigger terminal configured to receive the global trigger; a second timer configured to generate a second internal trigger after a second offset duration from the global trigger; a second millimeter-wave radar sensor circuit; and a second controller configured to use the second millimeter-wave radar sensor circuit to generate a second millimeter-wave radar signal based on the second internal trigger, wherein the second offset duration is different from the first offset duration, so that the first millimeter-wave radar signal and the second millimeter-wave radar signal are transmitted sequentially and without time overlap.

[0080] Example 19. The system of Example 18, wherein the first millimeter-wave radar further comprises a first serial peripheral interface (SPI) slave circuit, wherein the second millimeter-wave radar further comprises a second SPI slave circuit, wherein the application processor comprises an SPI master circuit coupled to the first and second SPI slave circuits via an SPI bus, and wherein the application processor is configured to program the first offset duration into the first millimeter-wave radar using the SPI bus and to program the second offset duration into the second millimeter-wave radar using the SPI bus.

[0081] Example 20. A system according to Example 18 or 19, wherein the first timer includes a first counter, wherein the first millimeter-wave radar further includes a first register configured to store a first time offset threshold corresponding to the first offset duration, wherein the second timer includes a second counter, and wherein the second millimeter-wave radar further includes a second register configured to store a second time offset threshold corresponding to the second offset duration.

[0082] Although the present invention has been described with reference to exemplary embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments and other embodiments of the present invention will become apparent to those skilled in the art upon reference to the description. Accordingly, the appended claims include any such modifications or embodiments.

Claims

1. A method comprising: using a data line of the first serial interface circuit to transmit a global trigger to the first millimeter-wave radar and the second millimeter-wave radar via a serial bus without using a signal line dedicated to the global trigger, wherein a frequency of the global trigger is less than a frequency of a clock signal of the first serial interface circuit; using the first serial interface circuit to transmit first data different from the global trigger to the first millimeter-wave radar through the serial bus; using the first serial interface circuit to transmit second data different from the global trigger to the second millimeter-wave radar through the serial bus; Using a first local serial interface circuit, using a first millimeter-wave radar, to receive a global trigger and the first data; Using a second local serial interface circuit, using a second millimeter-wave radar to receive the global trigger and the second data; generating a first internal trigger of the first millimeter-wave radar after a first offset duration from the global trigger; generating a second internal trigger of the second millimeter-wave radar after a second offset duration from the global trigger; Based on the first internal trigger, using the first millimeter-wave radar to start transmitting a first millimeter-wave radar signal; as well as Based on the second internal trigger, the second millimeter-wave radar starts transmitting a second millimeter-wave radar signal, wherein the second offset duration is different from the first offset duration, and wherein the first millimeter-wave radar signal and the second millimeter-wave radar signal are transmitted sequentially so as not to show time overlap.

2. The method according to claim 1, further comprising: The global trigger is generated using an application processor.

3. The method according to claim 1, further comprising: The global trigger is generated using the master output slave input MOSI line of the serial peripheral interface SPI.

4. The method according to claim 1, further comprising: programming the first offset duration into the first millimeter-wave radar; as well as The second offset duration is programmed into the second millimeter-wave radar.

5. The method according to claim 1, further comprising: After receiving the global trigger via the first millimeter-wave radar, starting a first digital counter of the first millimeter-wave radar, and generating the first internal trigger when a first count of the first digital counter reaches a first time offset threshold corresponding to the first offset duration; as well as After receiving the global trigger through the second millimeter-wave radar, a second digital counter of the second millimeter-wave radar is started, and when a second count of the second digital counter reaches a second time offset threshold corresponding to the second offset duration, the second internal trigger is generated. 6 . The method according to claim 5 , wherein the first time offset threshold is stored in a first register of the first millimeter-wave radar, and wherein the second time offset threshold is stored in a second register of the second millimeter-wave radar.

7. The method according to claim 6, further comprising: programming the first time offset threshold into the first register; as well as The second time offset threshold is programmed into the second register.

8. The method according to claim 1, further comprising: Beamforming is performed using the first millimeter-wave radar and the second millimeter-wave radar.

9. A system comprising: An application processor includes a first serial interface circuit coupled to a serial bus, the application processor being configured to: generating a global trigger, and transmitting the global trigger to the first millimeter-wave radar and the second millimeter-wave radar using a data line of the first serial interface circuit without using a signal line dedicated to the global trigger, wherein a frequency of the global trigger is less than a frequency of a clock signal of the first serial interface circuit; using the first serial interface circuit to transmit first data different from the global trigger to the first millimeter-wave radar through the serial bus; as well as using the first serial interface circuit to transmit second data different from the global trigger to the second millimeter-wave radar through the serial bus; The first millimeter-wave radar, including: a first local serial interface circuit coupled to the serial bus, wherein the first local serial interface circuit is configured to receive the global trigger and the first data through the serial bus; a first timer configured to generate a first internal trigger after a first offset duration from the global trigger; a first millimeter-wave radar sensor circuit; and a first controller configured to generate a first millimeter-wave radar signal based on the first internal trigger using the first millimeter-wave radar sensor circuit; and The second millimeter-wave radar includes: a second local serial interface circuit coupled to the serial bus, the second local serial interface circuit being configured to receive the global trigger and the second data via the serial bus; a second timer configured to generate a second internal trigger after a second offset duration from the global trigger; a second millimeter-wave radar sensor circuit; and A second controller is configured to generate a second millimeter-wave radar signal based on the second internal trigger using the second millimeter-wave radar sensor circuit, wherein the second offset duration is different from the first offset duration so that the first millimeter-wave radar signal and the second millimeter-wave radar signal are transmitted sequentially and without time overlap.

10. The system of claim 9, wherein the first local serial interface circuit comprises a first serial peripheral interface (SPI) slave circuit, wherein the second local serial interface circuit comprises a second SPI slave circuit, and wherein the first serial interface circuit comprises an SPI master circuit coupled to the first SPI slave circuit and the second SPI slave circuit via an SPI bus. 11 . The system of claim 10 , wherein the application processor is configured to send the global trigger to the first SPI slave circuit and the second SPI slave circuit using the SPI bus.

12. The system of claim 10, wherein the application processor is configured to: Programming the first offset duration into the first millimeter-wave radar using the SPI bus; and The second offset duration is programmed into the second millimeter-wave radar using the SPI bus. 13 . The system according to claim 10 , further comprising a printed circuit board (PCB) coupled to the application processor and coupled to the first millimeter wave radar and the second millimeter wave radar, wherein the PCB includes the SPI bus.

14. The system of claim 9, wherein the first timer comprises a first counter, wherein the first millimeter-wave radar further comprises a first register configured to store a first time offset threshold corresponding to the first offset duration, wherein the second timer comprises a second counter, and wherein the second millimeter-wave radar further comprises a second register configured to store a second time offset threshold corresponding to the second offset duration.

15. The system of claim 14 , wherein the first counter is configured to start counting up after receiving the global trigger and to generate the first internal trigger when a first count of the first counter reaches the first time offset threshold, and wherein the second counter is configured to start counting up after receiving the global trigger and to generate the second internal trigger when a second count of the second counter reaches the second time offset threshold. 16 . The system of claim 9 , wherein the application processor is configured to send the global trigger using a GPIO terminal coupled to respective trigger terminals of the first millimeter-wave radar and the second millimeter-wave radar.

17. A system comprising: An application processor includes a first serial interface circuit coupled to a serial bus, the application processor being configured to: generating a global trigger and transmitting the global trigger to the first millimeter-wave radar and the second millimeter-wave radar using the first serial interface circuit without using a dedicated trigger line, wherein the global trigger is transmitted through a master output slave input MOSI line of a serial peripheral interface SPI; using the first serial interface circuit to transmit first data different from the global trigger to the first millimeter-wave radar through the serial bus; as well as using the first serial interface circuit to transmit second data different from the global trigger to the second millimeter-wave radar through the serial bus; The first millimeter-wave radar, including: a first local serial interface circuit coupled to the serial bus, wherein the first local serial interface circuit is configured to receive the global trigger and the first data through the serial bus; a first timer configured to generate a first internal trigger after a first offset duration from the global trigger; a first millimeter-wave radar sensor circuit; and a first controller configured to generate a first millimeter-wave radar signal based on the first internal trigger using the first millimeter-wave radar sensor circuit; and The second millimeter-wave radar includes: a second local serial interface circuit coupled to the serial bus, the second local serial interface circuit being configured to receive the global trigger and the second data via the serial bus; a second timer configured to generate a second internal trigger after a second offset duration from the global trigger; a second millimeter-wave radar sensor circuit; and A second controller is configured to generate a second millimeter-wave radar signal based on the second internal trigger using the second millimeter-wave radar sensor circuit, wherein the second offset duration is different from the first offset duration so that the first millimeter-wave radar signal and the second millimeter-wave radar signal are transmitted sequentially and without time overlap.

18. The system of claim 17 , wherein the first local serial interface circuit comprises a first serial peripheral interface (SPI) slave circuit, wherein the second local serial interface circuit comprises a second SPI slave circuit, wherein the first serial interface circuit comprises an SPI master circuit coupled to the first SPI slave circuit and the second SPI slave circuit via an SPI bus, and wherein the application processor is configured to: Programming the first offset duration into the first millimeter-wave radar using the SPI bus; and The second offset duration is programmed into the second millimeter-wave radar using the SPI bus.

19. The system of claim 17, wherein the first timer comprises a first counter, wherein the first millimeter-wave radar further comprises a first register configured to store a first time offset threshold corresponding to the first offset duration, wherein the second timer comprises a second counter, and wherein the second millimeter-wave radar further comprises a second register configured to store a second time offset threshold corresponding to the second offset duration. 20 . The system of claim 17 , wherein the first millimeter-wave radar and the second millimeter-wave radar are configured to perform beamforming.

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