Multi-stream MIMO / Beamforming Radar

Abstract

An advanced system (101, 3500) and method are provided. The advanced system and method include a set of antennas (3526) including a set of transmit antennas and a set of receive antennas, a digital beamformer (3516), and a processor (225) operatively connected to the set of antennas and the digital beamformer. The processor is configured to identify a set of orthogonal multiple-input multiple-output (MIMO) signals, generate a first set of beams via the digital beamformer, and map the set of orthogonal MIMO signals to each of the generated set of beams. The advanced system and method further include a transceiver (210) operatively connected to the processor. The transceiver is configured to transmit a first signal based on the first set of beams to a target scene via a set of transmit antennas of the set of antennas, and receive a second signal based on a second set of beams reflected or backscattered from the target scene via a set of receive antennas of the set of antennas.

Description

[Technical field]

[0001] The present disclosure relates generally to radar system technology and more specifically to multi-stream MIMO / beamforming radar in next generation radar systems. [Background technology]

[0002] For high resolution radars, such as those for automotive applications, the number of hypervoxels in the 4D sphere is large, but the measurement time is limited due to the required frame rate. Phased array beamforming using analog beamformers is limited in frame rate due to the number of simultaneous beams that can be generated and the number of signals that can be transmitted simultaneously. Summary of the Invention [Problem to be solved by the invention]

[0003] In the present disclosure, a multi-stream transmission and reception scheme for high-resolution radar is provided. The present disclosure provides sub-band coded OFDM for high-resolution radar. The present disclosure enables transmission and reception of signals on multiple beams in beamforming mode or multiple antennas in MIMO mode without interference between beams or antennas. The provided embodiment reduces acquisition time by a factor of MxN, where M is the number of transmit beams (or MIMO layers) and N is the number of receive beams (or MIMO layers). [Means for solving the problem]

[0004] In one embodiment, an advanced system is provided. The advanced system includes a set of antennas including a set of transmit antennas and a set of receive antennas, a digital beamformer, and a processor operatively connected to the set of antennas and the digital beamformer, the processor configured to identify a set of orthogonal multiple-input multiple-output (MIMO) signals, generate a first set of beams via the digital beamformer, and map the set of orthogonal MIMO signals to each of the generated set of beams. The advanced system further includes a transceiver operatively connected to the processor, the transceiver configured to transmit a first signal based on the first set of beams to a target scene via a set of transmit antennas of the set of antennas, and receive a second signal based on the second set of beams reflected or backscattered from the target scene via a set of receive antennas of the set of antennas.

[0005] In another embodiment, a method of an advanced system is provided, the method including identifying a set of orthogonal multiple-input multiple-output (MIMO) signals, generating a first set of beams, mapping the set of orthogonal MIMO signals to each of the generated set of beams, transmitting a first signal based on the first set of beams to a target scene, and receiving a second signal based on a second set of beams that is reflected or backscattered from the target scene.

[0006] In yet another embodiment, a non-transitory computer-readable medium is provided that comprises program code that, when executed by at least one processor, causes an advanced system to identify a set of orthogonal multiple-input multiple-output (MIMO) signals, generate a first set of beams, map the set of orthogonal MIMO signals to each of the generated set of beams, transmit a first signal based on the first set of beams to a target scene, and receive a second signal based on a second set of beams that are reflected or backscattered from the target scene.

[0007] Other technical features may be readily apparent to those skilled in the art from the accompanying drawings, the following description, and the appended claims.

[0008] Before embarking on the detailed description below, it may be advantageous to provide definitions of certain words and phrases used throughout this patent document. The term "couple" and its derivatives refer to a direct or indirect connection between two or more elements, regardless of whether the two or more elements are in physical contact with one another. The terms "transmit," "receive," and "communicate," and their derivatives, encompass both direct and indirect communication. The terms "including" and "comprises," and their derivatives, mean an open-ended inclusion. The term "or" is inclusive and / or. The phrase "associated with" and its derivatives mean including, contained within, interconnected with, including, contained within, connected to or with, coupled to or with, communicable with, cooperate with, interleave with, juxtaposed to, in close proximity to, bound to or with, having, having the property of, having a relationship to or with, and the like. The term "controller" refers to any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware, or a combination of hardware with software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used and that only one item in the list may be required. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A, B, and C.

[0009] Moreover, the various functions described below may be implemented or supported by one or more computer programs, each of which is formed from computer-readable program code and embodied in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or portions thereof adapted for implementation in suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, such as source code, object code, executable code, etc. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, compact disc (CD), digital video disc (DVD), or any other type of memory. "Non-transitory" computer-readable media excludes wired, wireless, optical, or other communication links that transfer transient electrical or other signals. Non-transitory computer-readable media includes media that can store data permanently and media that can store data and later be overwritten, such as rewritable optical disks or erasable memory devices.

[0010] Definitions of other specific words and phrases are provided throughout this patent document, and those of skill in the art should understand that in many, if not most, cases such definitions apply to prior and future uses of such defined words and phrases. [Brief description of the drawings]

[0011] For a more complete understanding of the present disclosure, reference is made to the following descriptions taken in conjunction with the accompanying drawings, in which: [Figure 1] 1 illustrates an exemplary wireless network in accordance with an embodiment of the present invention. [Diagram 2] FIG. 1 illustrates an exemplary gNB in ​​accordance with an embodiment of the present invention. [Diagram 3] FIG. 2 illustrates an exemplary UE according to an embodiment of the present invention. [Figure 4] FIG. 1 illustrates an exemplary 2D virtual antenna array for imaging in accordance with the present disclosure. [Diagram 5] FIG. 13 illustrates an exemplary synthesis of a larger aperture in azimuth, in accordance with the present disclosure. [Figure 6] FIG. 13 illustrates another exemplary synthesis of a larger aperture in azimuth, according to the present disclosure. [Figure 7] FIG. 1 illustrates an exemplary automotive antenna design in accordance with the present disclosure. [Figure 8] FIG. 2 illustrates another exemplary automotive antenna design in accordance with the present disclosure. [Figure 9] FIG. 2 illustrates an exemplary virtual 2D circular antenna array in accordance with the present disclosure. [Figure 10] FIG. 1 illustrates an exemplary automotive installation of an imaging radar in accordance with the present disclosure. [Figure 11] FIG. 1 illustrates an exemplary building installation and factory automation according to the present disclosure. [Figure 12] FIG. 1 illustrates another exemplary in-building installation and factory automation in accordance with the present disclosure. [Figure 13] FIG. 1 illustrates an exemplary beamformer illumination principle according to the present disclosure. [Figure 14] FIG. 1 illustrates an exemplary hybrid beamforming general architecture in accordance with the present disclosure. [Figure 15] FIG. 1 illustrates an exemplary hybrid beamforming using OFDM waveforms in accordance with the present disclosure. [Figure 16] FIG. 1 illustrates an example hybrid beamforming with a MIMO OFDM waveform in accordance with the present disclosure. [Figure 17] FIG. 1 illustrates an example beamforming using a virtual antenna array in accordance with the present disclosure. [Figure 18] FIG. 1 illustrates an example transmit beamforming according to the present disclosure. [Figure 19] FIG. 1 illustrates an example receive beamforming according to the present disclosure. [Figure 20] FIG. 1 illustrates an example receive beamforming using M antenna arrays according to the present disclosure. [Figure 21] FIG. 1 illustrates an exemplary multi-beam illumination and scheduling diagram according to the present disclosure. [Figure 22] FIG. 1 illustrates an exemplary apparatus according to the present disclosure. [Diagram 23] FIG. 2 illustrates an exemplary sensor and application software according to the present disclosure. [Figure 24] FIG. 2 illustrates an example frame structure of a radar waveform according to the present disclosure. [Diagram 25] FIG. 1 illustrates an exemplary imaging radar according to the present disclosure. [Figure 26] FIG. 1 illustrates an example waveform MIMO / beamforming radar transmission according to the present disclosure. [Figure 27] FIG. 1 illustrates an exemplary MIMO / BF imaging radar in beamforming mode in accordance with the present disclosure. [Figure 28] FIG. 1 illustrates an example multi-stream beamforming radar processing in accordance with the present disclosure. [Figure 29] FIG. 1 illustrates another example multi-stream beamforming radar processing according to the present disclosure. [Diagram 30] FIG. 1 illustrates an exemplary simultaneous operation of short-range and long-range radar in accordance with the present disclosure. [Diagram 31] 1A-1C illustrate exemplary range-dependent imaging operations according to the present disclosure. [Diagram 32] FIG. 1 illustrates an exemplary geometry for imaging according to the present disclosure. [Diagram 33] FIG. 2 illustrates an exemplary image formation algorithm according to the present disclosure. [Diagram 34] FIG. 2 illustrates an example power loss for each transmit and receive path in a mmWave transceiver according to the present disclosure. [Figure 35A]FIG. 1 illustrates an exemplary 4D imaging radar in accordance with the present disclosure. [Figure 35B] FIG. 1 illustrates an exemplary antenna array according to the present disclosure. [Diagram 36] FIG. 1 illustrates an example overall transmit / receiver processing architecture according to the present disclosure. [Figure 37] FIG. 2 illustrates an example frequency domain range Doppler processing of a radar waveform according to the present disclosure. [Figure 38] FIG. 2 illustrates an example time domain representation of a compressed range process of a transmitted signal, a received signal, a circular shift, and an addition followed by an accumulation operation in accordance with the present disclosure. [Figure 39] FIG. 1 illustrates an example compressed range processing of radar waveforms according to the present disclosure. [Diagram 40] FIG. 13 illustrates an exemplary computational complexity of range processing according to the present disclosure. [Diagram 41] 4 illustrates example decision statistics after range processing for an AWGN channel in accordance with the present disclosure. [Diagram 42] 4 illustrates an example slice of decision statistics after range-Doppler processing for an AWGN channel in accordance with the present disclosure. [Diagram 43] FIG. 2 illustrates an exemplary 2D range Doppler map after range Doppler processing in accordance with the present disclosure. [Diagram 44] 1 is a flowchart of a multi-stream MIMO / beamforming radar method according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 1-14 described below, and the various embodiments used to illustrate the principles of the present disclosure in this patent document, are illustrative only and should not be construed as limiting the scope of the present disclosure in any way. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any type of suitably configured device or system.

[0013] 1-3 illustrate various embodiments implemented by using Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA) communication techniques in a wireless communication system. The illustrations in FIG. 1-3 are not meant to imply physical or architectural limitations to the manner in which various embodiments may be implemented. Various embodiments of the present disclosure may be implemented in any suitably configured communication system.

[0014] 1 illustrates an exemplary wireless network in accordance with an embodiment of the present invention. The embodiment of the wireless network illustrated in FIG. 1 is for illustrative purposes only. Other embodiments of the wireless network 100 may be used without departing from the scope of the present disclosure.

[0015] 1, the wireless network includes gNB101, gNB102, and gNB103. gNB101 communicates with gNB102 and gNB103. gNB101 also communicates with at least one network 130, such as the Internet, a private Internet Protocol (IP) network, or other data network. In one embodiment, such gNBs 101-103 may be implemented as advanced systems including radar systems supporting multi-stream MIMO and / or beamforming radar.

[0016] The gNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipments (UEs) within the coverage area 120 of the gNB 102. The first plurality of UEs includes a UE 111 that may be located in a small business (SB), a UE 112 that may be located in an enterprise (E), a UE 113 that may be located in a WiFi hotspot (HS), a UE 114 that may be located in a first residence (R), a UE 115 that may be located in a second residence (R), and a UE 116 that may be a mobile device (M) such as a mobile phone, a wireless laptop, a wireless PDA, etc. The gNB 103 provides wireless broadband access to the network 130 for a second plurality of user equipments (UEs) within the coverage area 125 of the gNB 103. The second plurality of UEs includes the UE 115 and the UE 116. In some embodiments, one or more gNBs 101-103 may communicate with each other and with UEs 111-116 using 5G, LTE, LTE-A, WiMAX, WiFi, or other wireless communications technologies. In one embodiment, such UEs 111-111 may be implemented as advanced systems including radar systems supporting multi-stream MIMO and / or beamforming radar.

[0017] Depending on the network type, the term "base station" or "BS" may refer to any component (or collection of components) configured to provide wireless access to a network, such as a transmission point (TP), a transmit / receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wireless-enabled device. A base station may provide wireless access according to one or more wireless communications protocols, such as, for example, 5G 3GPP New Radio Wireless Interface / Access (NR), Long Term Evolution (LTE), LTE Advanced (LTE-A), High Speed ​​Packet Access (HSPA), Wi-Fi 802.11a / b / g / n / ac, etc. For convenience, the terms "BS" and "TRP" are used interchangeably in this patent specification to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, the term "user equipment" or "UE" may refer to any component, such as a "mobile station," a "subscriber station," a "remote terminal," a "wireless terminal," a "receiving point," or a "user device." For convenience, in this patent specification, the terms "user equipment" and "UE" are used to refer to remote wireless equipment that wirelessly accesses a BS, regardless of whether the UE is a mobile device (such as a mobile phone or smartphone) or is typically considered a fixed device (such as a desktop computer or vending machine).

[0018] The dotted lines indicate the approximate extents of coverage areas 120 and 125, which are shown as approximately circular for purposes of illustration and explanation only. It should be clearly understood that coverage areas associated with gNBs, such as coverage areas 120 and 125, may have other shapes, including irregular shapes, depending on the configuration of the gNB and variations in the radio environment associated with natural and man-made obstacles.

[0019] As described in more detail below, one or more of the UEs 111-116 include circuitry, programming, or a combination thereof for reliable reception of data and control information in advanced wireless communication systems. In a particular embodiment, one or more of the gNBs 101-103 include circuitry, programming, or a combination thereof for efficient synthetic aperture antenna array design and beamforming for 3D imaging, localization, and positioning in advanced wireless systems.

[0020] Although FIG. 1 illustrates an example of a wireless network, various modifications may be made to FIG. 1. For example, a wireless network may include any number of gNBs and any number of UEs in any suitable arrangement. Additionally, gNB 101 may directly communicate with any number of UEs and provide those UEs with wireless broadband access to network 130. Similarly, each gNB 102-103 may directly communicate with network 130 and provide UEs with direct wireless broadband access to network 130. Additionally, gNBs 101, 102, and / or 103 may provide access to other or additional external networks, such as an external telephone network or other type of data network.

[0021] Figure 2 illustrates an exemplary gNB 102 in accordance with an embodiment of the present invention. The embodiment of gNB 102 illustrated in Figure 2 is for illustrative purposes only, and gNBs 101 and 103 of Figure 1 may have the same or similar configurations. However, gNBs have a variety of configurations, and Figure 2 is not intended to limit the scope of the present disclosure to any particular implementation of a gNB.

[0022] 2, the gNB 102 includes multiple antennas 205a-205n, multiple RF transceivers 210a-210n, transmit (TX) processing circuitry 215, and receive (RX) processing circuitry 220. The gNB 102 also includes a controller / processor 225, a memory 230, and a backhaul or network interface 235.

[0023] TX processing circuitry 215 receives analog or digital data (such as voice data, web data, email, or interactive video game data) from controller / processor 225. TX processing circuitry 215 encodes, multiplexes, and / or digitizes outgoing baseband data to generate processed baseband or IF signals. RF transceivers 210a-210n receive the outgoing processed baseband or IF signals from TX processing circuitry 215 and upconvert the baseband or IF signals to RF signals that are transmitted via antennas 205a-205n.

[0024] The RF transceivers 210a-210n receive incoming RF signals, such as signals reflected by a UE or any other object in the network 100, from the antennas 205a-205n. The RF transceivers 210a-210n downconvert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are sent to the RX processing circuitry 220, which generates processed baseband signals by filtering, decoding, digitizing, and / or decompressing or correlating the baseband or IF signals. The RX processing circuitry 220 sends the processed baseband signals to the controller / processor 225 for further processing.

[0025] The controller / processor 225 may include one or more processors or other processing devices that control the overall operation of the gNB 102. For example, the controller / processor 225 may control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceivers 210a-210n, the RX processing circuitry 220, and the TX processing circuitry 215 in accordance with well-known principles. The controller / processor 225 may also support additional functionality, such as more advanced wireless communication functions. For example, the controller / processor 225 may support beamforming or directional routing operations in which outgoing signals from multiple antennas 205a-205n are weighted differently to effectively steer the outgoing signals in a desired direction. Any of a wide variety of other functions may be supported by the controller / processor 225 in the gNB 102.

[0026] The controller / processor 225 may also execute programs and other processes, such as an OS, that reside in the memory 230. The controller / processor 225 may move data in and out of the memory 230 as required by the executing processes.

[0027] The controller / processor 225 is also coupled to a backhaul or network interface 235. The backhaul or network interface 235 enables the gNB 102 to communicate with other devices or systems over a backhaul connection or network. The interface 235 may support communication over any suitable wired or wireless connection(s). For example, if the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G, LTE, or LTE-A), the interface 235 may enable the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection. If the gNB 102 is implemented as an access point, the interface 235 may enable the gNB 102 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface 235 includes any suitable structure supporting communication over a wired or wireless connection, such as an Ethernet or RF transceiver.

[0028] The memory 230 is coupled to the controller / processor 225. A portion of the memory 230 may include RAM, and another portion of the memory 230 may include flash memory or other ROM.

[0029] Although FIG. 2 illustrates one example of a gNB 102, various modifications may be made to FIG. 2. For example, the gNB 102 may include any number of each of the components shown in FIG. 2. As a particular example, a ground station (e.g., an access point) may include several interfaces 235, and the controller / processor 225 may support a routing function for routing data between different network addresses. As another particular example, while shown as including a single instance of the TX processing circuitry 215 and a single instance of the RX processing circuitry 220, the gNB 102 may include multiple instances of each (e.g., one per RF transceiver). Additionally, various components of FIG. 2 may be combined, further subdivided, or omitted, and components may be added according to particular needs.

[0030] Figure 3 illustrates an exemplary UE 116 in accordance with an embodiment of the present invention. The embodiment of UE 116 illustrated in Figure 3 is for illustrative purposes only, and UEs 111-115 of Figure 1 may have the same or similar configurations. However, UEs have a variety of configurations, and Figure 3 is not intended to limit the scope of the present disclosure to any particular implementation of a UE.

[0031] The advanced communication device may be implemented as part of a base station (BS, gNB) in FIG. 2 or as a UE in FIG. 3, with reference to the transmitter or receiver arrays in FIG. 14, FIG. 15, and FIG. 16 providing hybrid beamforming operation based on all functional blocks.

[0032] 3, the UE 116 includes an antenna 305, a radio frequency (RF) transceiver 310, a TX processing circuit 315, and a receive (RX) processing circuit 325. The UE 116 also includes a processor 340, an input / output (I / O) interface (IF) 345, a touch screen 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) 361 and one or more applications 362.

[0033] The RF transceiver 310 receives from the antenna 305 incoming RF signals transmitted by the gNBs of the network 100. The RF transceiver 310 downconverts the incoming RF signals to generate intermediate frequency (IF) or baseband signals. The IF or baseband signals are sent to the RX processing circuitry 325, which generates processed baseband signals by filtering, decoding, and / or digitizing, and / or decompressing or correlating the baseband or IF signals. The RX processing circuitry 325 sends the processed baseband signals to the processor 340 for further processing (such as web browsing of data).

[0034] The TX processing circuitry 315 receives outgoing baseband analog data (such as web data, email, or interactive video game data) from the processor 340. The TX processing circuitry 315 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver 310 receives the outgoing processed baseband or IF signal from the TX processing circuitry 315 and upconverts the baseband or IF signal to an RF signal that is transmitted via the antenna 305.

[0035] The processor 340 may include one or more processors or other processing devices and may execute an OS 361 stored in memory 360 to control the overall operation of the UE 116. For example, the processor 340 may control the reception of forward channel signals and the transmission of reverse channel signals by the RF transceiver 310, the RX processing circuitry 325, and the TX processing circuitry 315 in accordance with well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

[0036] The processor 340 may also execute other processes and programs resident in the memory 360, such as processes for beam management. The processor 340 may move data in and out of the memory 360 as required by the executing processes. In some embodiments, the processor 340 is configured to execute applications 362 based on an OS 361 or in response to signals received from the gNB or an operator. The processor 340 is also coupled to an I / O interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. The I / O interface 345 is the communication path between these accessories and the processor 340.

[0037] The processor 340 is also coupled to a touchscreen 350 and a display 355. An operator of the UE 116 can use the touchscreen 350 to input data into the UE 116. The display 355 may be a liquid crystal display, a light emitting diode display, or other display capable of rendering text and / or at least limited graphics from a website, etc.

[0038] The memory 360 is coupled to the processor 340. A portion of the memory 360 may include random access memory (RAM), and another portion of the memory 360 may include flash memory or other read-only memory (ROM).

[0039] Although FIG. 3 illustrates an example of a UE 116, various modifications to FIG. 3 may be made. For example, various components of FIG. 3 may be combined, further subdivided, or omitted, and components may be added according to particular needs. As a particular example, the processor 340 may be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Also, while FIG. 3 illustrates a UE 116 configured as a mobile phone or smartphone, the UE may be configured to operate as other types of mobile or fixed devices.

[0040] Despite its simplicity, Code Division Multiple Access (CDMA) systems are well known to suffer from interference and multipath dispersion.

[0041] The advantages of Orthogonal Frequency Division Multiplexing (OFDM) over Frequency Modulated Continuous Wave (FMCW) radar are well understood: waveform generation is simple, reducing transceiver complexity compared to FMCW or chirp sequence modulation; the waveform does not require linear frequency generation in hardware; unlike phase modulated signals which are susceptible to self-interference and multipath interference, OFDM waveforms do not have stringent phase noise requirements and do not suffer from multipath interference; and OFDM is ideally suited for MIMO processing.

[0042] Despite their advantages, generating and processing OFDM signals for high-resolution radar is challenging due to the wideband processing required for high-resolution radar. The signal bandwidth of 76GHz-81GHz automotive radar is 1GHz-5GHz, requiring analog-to-digital conversion (ADC) rates of over 10Gsps with a large number of bits. For 3D radar imaging, which requires tens to hundreds of channels, wideband OFDM radar systems are cost-prohibitive. Therefore, commercial radar transceivers rely on FMCW signals.

[0043] FIG. 4 illustrates an exemplary 2D virtual antenna array 400 for imaging according to the present disclosure. The embodiment of the 2D virtual antenna array 400 for imaging illustrated in FIG. 4 is for illustrative purposes only. One or more of the components illustrated in FIG. 4 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0044] FIG. 4 illustrates an exemplary two-dimensional (2D) virtual antenna array for imaging according to the present disclosure. As illustrated in FIG. 4, the 2D virtual antenna array for imaging includes a transmit (Tx) antenna 402 and a receive (Rx) antenna 404. At the transmitter, azimuth beamforming with a one-dimensional (1D) linear array is performed, and a sequential scan in azimuth is performed. At the receiver, vertical beamforming with vertical resolution is performed. As illustrated in FIG. 4, 64-channel angle-of-arrival (AoA) antennas are provided. In one embodiment, the 2D virtual antenna array can use a MIMO antenna array (e.g., 2 / 4 / 8 orthogonal channels). As explained above, the 2D virtual antenna array includes N 2 Advantages may include a reduction in the number of paths to 2N paths (e.g., fewer ADCs / DACs and less power consumption in the transceiver), reduced antenna size and design, and associated reduction in DAC / ADC, IF, and power consumption circuits. The virtual antenna 406 may represent the Tx antenna 402 and the Rx antenna 404.

[0045] FIG. 5 illustrates an exemplary synthesis of larger apertures in azimuth 500 according to the present disclosure. The exemplary synthesis of larger apertures in azimuth 500 illustrated in FIG. 5 is for illustrative purposes only. One or more of the components illustrated in FIG. 5 may be implemented in a specialized circuit configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure. As illustrated in FIG. 5, the synthesis of larger apertures in azimuth 500 includes an Rx antenna 502 and a synthesis antenna array 504.

[0046] FIG. 6 shows another example of a larger aperture synthesis in azimuth 600 according to the present disclosure. The example of a larger aperture synthesis in azimuth 600 shown in FIG. 6 is for illustrative purposes only. One or more of the components shown in FIG. 6 can be implemented in a specialized circuit configured to perform the described functions, or one or more of the components can be implemented by one or more processors executing instructions to perform the described functions. Other embodiments can be used without departing from the scope of the present disclosure. As shown in FIG. 6, the larger aperture synthesis in azimuth 600 includes an Rx antenna 602 and a synthesis antenna array 604.

[0047] 5 and 6 show an example synthesis of a larger aperture in azimuth according to the present disclosure. As shown in FIG. 5, the number of transmit paths is M 2 N to M+MN, where M is the antenna array size and N is the number of Rx antenna columns. For example, when M=8, N=4, 320 paths are reduced to 40 paths (88% savings), and when M=8, N=8, 512 paths are reduced to 72 paths (86% savings). As shown in FIG. 5, the Rx antenna 502 and the Tx antenna 506 can be combined into a combined antenna array 504.

[0048] 6 shows the synthesis of a larger aperture in azimuth that can provide an adjustable vertical field of view. As shown in FIG. 6, the Rx antenna 602 and the Tx antenna 606 can be synthesized into a synthetic antenna array 604.

[0049] FIG. 7 shows an exemplary automobile antenna design 700 according to the present disclosure. One embodiment of the automobile antenna design 700 shown in FIG. 7 is for illustrative purposes only. One or more of the components shown in FIG. 7 can be implemented in a special circuit configured to perform the described functions, or one or more of the components can be implemented by one or more processors that execute instructions to perform the described functions. Other embodiments can be used without departing from the scope of the present disclosure. As shown in FIG. 7, the automobile antenna design 700 includes a Tx antenna 701 and an Rx antenna 702.

[0050] FIG. 8 illustrates another exemplary automobile antenna design 800 according to the present disclosure. The embodiment of the automobile antenna design 800 illustrated in FIG. 8 is for illustrative purposes only. One or more of the components illustrated in FIG. 8 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0051] 7 and 8 show exemplary automotive antenna designs according to the present disclosure. As shown in FIG. 7, for example, a 64x32 virtual array of a 77GHz automobile antenna design is shown. As shown in FIG. 7, the 64x32 virtual array includes an antenna panel for Tx that includes an array of 64 elements in azimuth and 64 elements in elevation, and 8 vertical arrays for Rx. As shown in FIG. 7, the Tx antenna 701 and the Rx antenna 702 can be arranged into 64 elements 704. As shown in FIG. 7, the rearview mirror 706 can be arranged into 64 elements 704. The rearview mirror can be constructed of layers 708.

[0052] For example, a 1024x64 virtual array for a 77GHz automotive antenna design is shown as shown in Figure 8. As shown in Figure 8, the 1024x64 virtual array includes an antenna panel for Tx containing an array of 128 elements in azimuth and 64 elements in elevation, as well as eight vertical arrays for Rx containing 64 elements in elevation. The 1024x64 virtual array shown in Figure 8 can be expanded to include two or more Tx antenna arrays (rows) for adjustable vertical transmit angles.

[0053] As shown in Fig. 8, the Tx antenna 801 and the Rx antenna 802 can be arranged into M elements 804. As shown in Fig. 8, an automobile bumper 806 with a bumper cover 808 can mount the M elements 804.

[0054] 9 illustrates an exemplary virtual 2D circular antenna array 900 according to the present disclosure. The embodiment of the virtual 2D circular antenna array 900 illustrated in FIG. 9 is for illustrative purposes only. One or more of the components illustrated in FIG. 9 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0055] FIG. 9 illustrates an exemplary virtual 2D circular antenna array according to the present disclosure. As shown in FIG. 9, 360-degree coverage can be achieved on poles, lampposts, and rooftops. As shown in FIG. 9, the circular antenna array 902 includes M Tx elements and N Rx elements 904. The circular antenna array 902 can be configured in poles and lampposts 906.

[0056] FIG. 10 illustrates an exemplary vehicle installation of an imaging radar 1000 according to the present disclosure. The embodiment of the vehicle installation of the imaging radar 1000 illustrated in FIG. 10 is for illustrative purposes only. One or more of the components illustrated in FIG. 10 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0057] 10 illustrates an exemplary vehicle installation of an imaging radar in accordance with the present disclosure. As shown in FIG. 10, multiple options for installing the imaging radar may be provided on a vehicle object 1002.

[0058] FIG. 11 illustrates an exemplary in-building installation and factory automation 1100 according to the present disclosure. The embodiment of the in-building installation and factory automation 1100 illustrated in FIG. 11 is for illustrative purposes only. One or more of the components illustrated in FIG. 11 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0059] FIG. 12 illustrates another exemplary in-building installation and factory automation 1200 according to the present disclosure. The embodiment of in-building installation and factory automation 1200 illustrated in FIG. 12 is for illustrative purposes only. One or more of the components illustrated in FIG. 12 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0060] As shown in Figure 11, antennas can be installed along two corners for in-building installations and factory automation. As shown in Figure 8, transmission is performed using a transmit (Tx) antenna 1102 with antenna aperture 1, and reception is performed using a receive (Rx) antenna 1104 with antenna aperture 2. In one embodiment, transmission is performed using a transmit (Tx) antenna with antenna aperture 2, and reception is performed using a receive (Rx) antenna with antenna aperture 1 (e.g., reverse).

[0061] One antenna element per aperture can be implemented as shown in Figure 12. In one embodiment, the antenna element of aperture 1 moves along the x-axis while transmitting a signal that illuminates objects in the room (e.g., Tx antenna 1202). In such an embodiment, the signal of each antenna element is weighted according to the beamforming equations provided by the present disclosure.

[0062] In one embodiment, for each antenna element position in Aperture 1, an antenna element in Aperture 2 moves along the y-axis while receiving signals reflected from the target (e.g., Rx antenna 1204). In such an embodiment, the signals of each antenna element are weighted according to the beamforming equations provided by the present disclosure.

[0063] FIG. 13 illustrates an exemplary beamformer illumination principle 1300 according to the present disclosure. The embodiment of the beamformer illumination principle 1300 illustrated in FIG. 13 is for illustrative purposes only. One or more of the components illustrated in FIG. 13 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0064] As shown in FIG. 13, a transmit beam 1302 is projected at the transmitter in a sequential scan manner, and a receive beam 1304 is projected simultaneously at the receiver.

[0065] FIG. 14 illustrates an exemplary hybrid beamforming general architecture 1400 according to the present disclosure. The embodiment of the hybrid beamforming general architecture 1400 illustrated in FIG. 14 is for illustrative purposes only. One or more of the components illustrated in FIG. 14 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0066] As shown in FIG. 14, the hybrid beamforming general architecture 1400 may be implemented as an advanced system, or the hybrid beamforming general architecture 1400 may be implemented as one of the components of an advanced system.

[0067] As shown in Figure 14, the hybrid beamformer circuit includes a sequence generation block 1402, a modulation block 1404, a digital BF block 1406, an IF / DAC block 1408, and an analog BF block 1410. As shown in Figure 14, subband precoding (W2) and wideband precoding (W1) are determined. In such a case, the wideband precoding (W1) is divided into two parts by: W1=W D TW A W A Analog beamforming within antenna subarrays W D : Digital beamforming matrix between subarrays T: D / A, IF / RF FIG. 15 illustrates an exemplary hybrid beamforming with OFDM waveform 1500 according to the present disclosure. The embodiment of hybrid beamforming with OFDM waveform 1500 illustrated in FIG. 15 is for illustrative purposes only. One or more of the components illustrated in FIG. 15 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0068] As shown in FIG. 15, the hybrid beamforming with OFDM waveforms 1500 may be implemented as an advanced system, or the hybrid beamforming with OFDM waveforms 1500 may be implemented as one of the components of an advanced system.

[0069] As shown in Figure 15, the hybrid beamformer circuit using OFDM waveform includes a sequence generation block 1502, a modulation block 1504, a RE mapping block 1506, an IFFT / CP block 1508, a digital BF block 1510, an IF / DAC block 1512, and an analog BF block 1514. As shown in Figure 15, subband precoding (W2) and wideband precoding (W1) are determined. In such a case, the wideband precoding (W1) is divided into two parts by: W1=W D TW A W A Analog beamforming within antenna subarrays W D : Digital beamforming matrix between subarrays FIG. 16 illustrates an exemplary hybrid beamforming with MIMO OFDM waveform 1600 according to the present disclosure. The embodiment of hybrid beamforming with MIMO OFDM waveform 1600 illustrated in FIG. 16 is for illustrative purposes only. One or more of the components illustrated in FIG. 16 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0070] As shown in FIG. 16, the hybrid beamforming with MIMO OFDM waveform 1600 may be implemented as an advanced system, or the hybrid beamforming with MIMO OFDM waveform 1600 may be implemented as one of the components of an advanced system.

[0071] As shown in FIG. 16, a hybrid beamformer circuit 1600 using an OFDM waveform includes a sequence generation block 1602, a layer mapping block 1604, a subband precoding block 1606, a set of resource element mapping blocks 1608, 1610, a set of IFFT / CP blocks 1612, 1614, a digital BF block 1610, an IF / DAC block 1618, and an analog BF block 1620.

[0072] As shown in Figure 16, the hybrid beamformer circuit using MIMO OFDM waveform includes a sequence generation and modulation block, a layer mapping block, a subband precoding block, multiple RE mapping blocks, multiple IFFT / CP blocks, a digital BF block, an IF / DAC block, and an analog BF block. As shown in Figure 13, the subband precoding (W2) and the wideband precoding (W1) are determined. In such a case, the wideband precoding (W1) is divided into two parts by: W1=W D TW A W A Analog beamforming within antenna subarrays W D : Digital beamforming matrix between subarrays T: D / A, IF / RF FIG. 17 illustrates an example beamforming with a virtual antenna array 1700 according to the present disclosure. The embodiment of beamforming with a virtual antenna array 1700 illustrated in FIG. 17 is for illustrative purposes only. One or more of the components illustrated in FIG. 17 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0073] As shown in FIG. 17, beamforming with a virtual antenna array is performed using N Rx elements 1702 and M Tx elements 1704.

[0074] FIG. 18 illustrates an example transmit beamforming 1800 according to the present disclosure. The embodiment of the transmit beamforming 1800 illustrated in FIG. 18 is for illustrative purposes only. One or more of the components illustrated in FIG. 18 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0075] As shown in Figure 18, the Tx beamforming circuit includes a number of baseband signal inputs 1802, a set of summer blocks 1804, 1806, and an IF / DAC block 1808 connected to a number of Tx antenna array (M,2) elements. In Figure 18, it is assumed that a simple antenna array with a digital beamformer is considered.

[0076] FIG. 19 illustrates an example receive beamforming 1900 according to the present disclosure. The embodiment of receive beamforming 1900 illustrated in FIG. 19 is for illustrative purposes only. One or more of the components illustrated in FIG. 19 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0077] As shown in Figure 19, the Rx beamforming circuit includes a number of Rx antenna arrays (N,2) 1902 and an IF / ADC block 1904 that includes a number of output signals that are summed to generate a baseband signal using a set of summers 1906, 1908. In Figure 16, it is assumed that a simple antenna array with a digital beamformer is considered.

[0078] FIG. 20 illustrates an exemplary receive beamforming with M antenna arrays 2000 according to the present disclosure. The embodiment of receive beamforming with M antenna arrays 2000 illustrated in FIG. 20 is for illustrative purposes only. One or more of the components illustrated in FIG. 20 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0079] As shown in Figure 20, an Rx beamforming circuit with M antenna arrays includes a number of Rx antenna arrays (N,2) 2002 and an IF / ADC block 2010 that includes a number of output signals that are summed to generate a baseband signal using a set of summers 2004, 2006. In Figure 20, it is assumed that a simple antenna array with a digital beamformer is considered.

[0080] FIG. 21 illustrates an exemplary multi-beam illumination and scheduling 2100 according to the present disclosure. The embodiment of multi-beam illumination and scheduling 2100 illustrated in FIG. 21 is for illustrative purposes only. One or more of the components illustrated in FIG. 21 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0081] As shown in FIG. 21, multi-beam illumination and scheduling are determined in elevation and azimuth. As shown in FIG. 21, multi-beam illumination in azimuth of Tx includes digital BF or Butler matrix. As shown in FIG. 21, two, four, or eight simultaneous beams are actually illuminated to the target scene 2102 from the antenna 2106. The receiver process is performed simultaneously for multiple azimuth and elevation angles. In such a case, the receiver can process the entire field of view (FoV) 2104 in elevation. As shown in FIG. 21, beam scheduling determines the azimuth and / or elevation angles based on configuration parameters. In such a case, the beam scheduling can be dynamically adjusted based on previous results (e.g., tracking objects in a specific area).

[0082] FIG. 22 illustrates an exemplary apparatus 2200 according to the present disclosure. The embodiment of the apparatus 2200 illustrated in FIG. 22 is for illustrative purposes only. One or more of the components illustrated in FIG. 22 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0083] As shown in FIG. 22, the apparatus 2200 may be implemented as an advanced system, or the apparatus 2200 may be implemented as one of the components of an advanced system.

[0084] As shown in FIG. 22, the device includes a 5G modem 2250, a mmWave imaging sensor 2202, and an advanced driver assistance system / autonomous vehicle (ADAS / AV) central processor 2228. The ADAS / AV central processor 2228 can be connected to the mmWave imaging sensor 2202 via a network such as Ethernet. The ADAS / AV central processor 2228 is further connected to a modem (e.g., 5G) 2250 that is connected to the mmWave imaging sensor 2202. The ADAS / AV central processor 2228 can be connected to a display 2252 and / or a computer (e.g., a terminal, a device, etc.) 2254 including at least one peripheral device. The ADAS / AV central processor 2228 can be further connected to another processor (e.g., a controller) that can be implemented in an external device and / or object (e.g., a vehicle).

[0085] The mmWave imaging sensor 2202 of the device comprises an antenna block 2204 including an antenna array 2206, a transceiver block 2208 including a filter 2210, a power amplifier (PA) 2212, a low noise amplifier (LNA) 2214, an analog-to-digital converter / digital-to-analog converter (ADC / DAV) 2216, and a digital beamforming (BF) 2218, and a system-on-chip (SOC) block 2220 including a 3D imaging modem 2222, a core post-processing sensor fusion 2224, and a camera 2226.

[0086] The ADAS / AV central processor 2228 of the device comprises an image processing block 2230, a central processing unit (CPU) 2232, a graphics processing unit (GPU) computer vision / machine learning (ML) 2234, internal memory 2236, fabric 2238, video codec H.264 2226, connectivity CAN / SAR Ethernet 2242, security block 2244, external memory interface 2240, and a system control block 2248.

[0087] FIG. 23 illustrates an exemplary sensor and application software 2300 according to the present disclosure. The embodiment of the sensor and application software 2300 illustrated in FIG. 23 is for illustrative purposes only. One or more of the components illustrated in FIG. 23 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0088] As shown in FIG. 23, an apparatus including beam pattern 2302, a sensor, a 3D imaging modem 2304, a transceiver and antenna array 2308 (e.g., detailed structure shown in 2306), and application software 2310 implemented on COTS hardware 2312 is configured for sensor fusion, stitching, computer vision, machine learning, 3D map generation, data aggregation, and system control.

[0089] FIG. 24 illustrates an example frame structure of a radar waveform 2400 according to the present disclosure. The embodiment of the frame structure of the radar waveform 2400 illustrated in FIG. 24 is for illustrative purposes only. One or more of the components illustrated in FIG. 24 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0090] Figure 24 shows the frame structure of a digital radar waveform. A "slot" 2402 consists of a cyclic prefix (CP), multiple OFDM symbols generated by DFT spreading of one or more CAZAC sequences, and a guard time (GT). GT is added depending on the required sequence length and the target scene coverage range. In format 1, only one sequence period is shown. A set of slots forms a subframe 2404. A set of subframes forms a frame 2406.

[0091] The range process performs correlation of the received OFDM symbol against the transmitted coded signal, followed by coherent accumulation of the OFDM symbols within a slot. The OFDM symbol length is determined as the inverse of the subcarrier spacing, while the slot length is set within the channel coherence time. As an example, for a 2 GHz RF bandwidth with a subcarrier spacing of 500 kHz, the FFT size is 4096 points, the OFDM symbol length is 2 μs, and the channel coherence time is 8 μs and 16 μs for speeds of 350 kmph and 175 kmph, respectively.

[0092] Multiple slots make up a subframe, which is used for Doppler processing. Each subframe signal illuminates targets within the antenna footprint (or beam in scanning radar) and causes reflections. Complete illumination of the target scene in the field of view results in a frame. The target scene is scanned multiple times, resulting in frame rates of 10 to 60 frames per second.

[0093] FIG. 25 illustrates an exemplary imaging radar 2500 according to the present disclosure. The embodiment of the imaging radar 2500 illustrated in FIG. 25 is for illustrative purposes only. One or more of the components illustrated in FIG. 25 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0094] As shown in FIG. 25, the imaging radar 2500 includes an Rx antenna array 2502, a target scene 2504, and a Tx antenna array 2506.

[0095] In traditional radar imaging, each beam may sequentially scan the target scene of interest. In 2D imaging, the target is illuminated by a narrow beam, which illuminates the area with a narrow transmit beam. For each illuminated area, the receiver sequentially scans the target area and estimates the angle of arrival. In analog beamforming, a single beam is typically generated due to the required hardware complexity. In high-resolution imaging, the number of scanned angle bins ranges from hundreds to thousands of points, and long acquisition times are required to generate a point cloud image.

[0096] At each dwell, the target scene is illuminated by the antenna and the received signal from the Rx antenna is processed for imaging.

[0097] FIG. 26 illustrates an exemplary waveform MIMO / beamforming radar transmission 2600 according to the present disclosure. The embodiment of the waveform MIMO / beamforming radar transmission 2600 illustrated in FIG. 26 is for illustrative purposes only. One or more of the components illustrated in FIG. 26 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0098] FIG. 26 shows the waveform of a MIMO / beamforming radar transmission. The MIMO / beamforming radar waveform is generated by a coded digital waveform, which is generated by encoding the signal in the frequency domain for OFDM radar waveforms, or in the time domain for phase modulated radar. The "signature" 2602 shows the slot signal from the orthogonal CAZAC sequence. The signature is beamformed by a digital beamformer or a hybrid beamformer, which is a combination of a digital beamformer and an analog beamformer. After beamforming, multiple streams of signals mapped to beams 2604 are transmitted simultaneously, with each beam illuminating a portion of the target scene. As shown in FIG. 26, the signature 2602 and beams 2604 are processed through a digital BF 2606, an IF / DAC 2608, and an analog BF 2610.

[0099] FIG. 27 illustrates an exemplary MIMO / BF imaging radar in beamforming mode 2700 according to the present disclosure. The embodiment of the MIMO / BF imaging radar in beamforming mode 2700 illustrated in FIG. 27 is for illustrative purposes only. One or more of the components illustrated in FIG. 27 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0100] Multiple beams are generated simultaneously by digital beamforming. Therefore, multiple points can be acquired per scan. At the transmitter, multiple beams are generated using the Tx antenna array 2706, with each beam illuminating a portion or portions of the target scene. In reality, signals from these beams interfere with each other, causing inter-beam interference, which appears as artifacts in the resulting image. At the receiver, signals are received at the Rx antenna array 2702 via the target scene 2704.

[0101] In this disclosure, multiple CAZAC sequences generated by DFT-spread OFDM are mapped to different beams. The sequences are mapped to each beam according to the following two approaches.

[0102] In one embodiment, multiple root CAZAC sequences are mapped to each beam, which ensures that the autocorrelation value of the received signal after correlation processing is low and minimizes the interference between beams.

[0103] In another embodiment, orthogonal CAZAC sequences with zero autocorrelation properties are generated by cyclic shifting of a root CAZAC sequence, which are then mapped to each beam.

[0104] Multiple sequences are transmitted simultaneously on multiple beams. At the receiver, multiple correlators corresponding to the multiple sequences are implemented for each beam. The receiver can handle up to MxN correlators, where M is the number of transmit beams (= the number of CAZAC sequences) and N is the number of receive beams.

[0105] In one example, when M=N=4, four beams are transmitted simultaneously. At the receiver, spatial processing of the four beams is performed, each computing correlation of four CAZAC sequences. This approach produces 16 points of the point cloud per dwell time, reducing acquisition time by a factor of 16.

[0106] FIG. 28 illustrates an exemplary multi-stream beamforming radar processing 2800 according to the present disclosure. The embodiment of the multi-stream beamforming radar processing 2800 illustrated in FIG. 28 is for illustrative purposes only. One or more of the components illustrated in FIG. 28 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0107] As shown in FIG. 28, the multi-stream beamforming radar processing 2800 may be implemented as an advanced system, or the multi-stream beamforming radar processing 2800 may be implemented as one of the components of an advanced system.

[0108] The details of the sequence generation, mapping and beamforming process are shown in Figure 28. Figure 28 shows digital beamforming with multi-beam transmission.

[0109] As shown in FIG. 28, the multi-stream beamforming radar comprises a set of CAZAC sequences 2802, a DFT block 2804, a complex conjugate block 2806, a subcarrier mapping 2808, an IFFT block 2810, a CP / GT insertion block 2812, a digital Tx beamformer block 2814, a DAC block 2816, an ADC block 2818, an Rx beamformer block 2820, a set of blocks 2822 including a CP removal block 2824, an FFT block 2826, a complex multiplication block 2828, an IFFT block 2830, and a Doppler DFT block 2832, a CFAR detector block 2834, and an arithmetic block 2836.

[0110] In hybrid beamforming, analog beamforming with phase shifters is implemented at RF after the ADC. The output signals of the digital beamformer are mapped to the antenna ports and the output signals are further beamformed using an analog beamformer with phase shifters.

[0111] In some embodiments, for M transmit paths and N receive paths, the acquisition time of the point cloud is reduced by a factor of MxN.

[0112] In MIMO mode, multiple antennas illuminate the target scene within the entire field of view. FIG. 29 illustrates another exemplary multi-stream beamforming radar processing 2900 according to the present disclosure. The embodiment of the multi-stream beamforming radar processing 2900 illustrated in FIG. 29 is for illustrative purposes only. One or more of the components illustrated in FIG. 29 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0113] The CAZAC sequence is mapped to each antenna port of the MIMO configuration. A block diagram of the multi-stream MIMO radar is shown in Figure 29.

[0114] As shown in FIG. 29, the multi-stream beamforming radar processing 2900 may be implemented as an advanced system, or the multi-stream beamforming radar processing 2900 may be implemented as one of the components of an advanced system.

[0115] As shown in FIG. 29, the multi-stream beamforming radar comprises a set of CAZAC sequences 2902, a DFT block 2904, a complex conjugate block 2906, a subcarrier mapping 2908, an IFFT block 2910, a CP / GT insertion block 2912, a DAC block 2914, an ADC block 2916, a set of blocks 2918 including a CP removal block 2920, an FFT block 2922, a complex multiplication block 2924, an IFFT block 2926, and a Doppler DFT block 2928, a special processing block 2930, a CFAR detector block 2932, and an arithmetic block 2934.

[0116] Multiple orthogonal CAZAC sequences generated by DFT-spread OFDM are mapped to antenna ports. At the receiver, range / Doppler processing is performed for each antenna port. After range / Doppler processing, spatial processing takes data from multiple antenna ports and focuses the image according to range. Spatial focusing applies range-dependent correction factors to the range / Doppler compressed data. In one embodiment, a computationally efficient image focusing algorithm using FFT can be applied as shown in the previous embodiment.

[0117] FIG. 30 illustrates an exemplary simultaneous operation 3000 of short-range and long-range radars according to the present disclosure. The embodiment of the simultaneous operation 3000 of short-range and long-range radars illustrated in FIG. 30 is for illustrative purposes only. One or more of the components illustrated in FIG. 30 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0118] For objects closer to the transmitting antenna, the received SINR is higher. Multiple MIMO streams are transmitted with a wide field of view, illuminating a wide field of view up to 170°.

[0119] As shown in FIG. 30, a car 3008 transmits beams at short range 3002, medium range 3004, and long range 3006.

[0120] In one embodiment, for simultaneous short-range and long-range operation, the transmission and reception of MIMO and beamforming modes apply alternating dwell times: when the subframe number is even, the transmission and reception of MIMO takes place; when the subframe number is odd, the transmission and reception of beamforming takes place.

[0121] In one embodiment, for simultaneous short-range, medium-range, and long-range operation, MIMO, MIMO and beamforming, and beamforming transmit / receive are applied sequentially within a subframe.

[0122] In one embodiment, spatial processing is performed at the receiver on the target distance after range / Doppler processing.

[0123] FIG. 31 illustrates an exemplary range-dependent imaging operation 3100 according to the present disclosure. The embodiment of the range-dependent imaging operation 3100 illustrated in FIG. 31 is for illustrative purposes only. One or more of the components illustrated in FIG. 31 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0124] The principle of range-dependent imaging operation is shown in Figure 31. Range-dependent spatial processing is applied after range-Doppler processing.

[0125] FIG. 32 is a diagram illustrating an example imaging geometry 3200 according to the present disclosure. The embodiment of imaging geometry 3200 shown in FIG. 32 is for illustrative purposes only. One or more of the components shown in FIG. 32 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0126] As shown in FIG. 32, an antenna array 3202 transmits a signal into a target scene 3204 .

[0127] In one embodiment, the digital imaging module performs computational imaging operations, such as an image formation algorithm, to determine the target reflectance, which is a portion of the signal (e.g., electromagnetic or optical signal incident on the target) reflected from the target. Thus, the digital imaging module uses the image formation algorithm to calculate voxels (volume pixels) with coordinates (x, y, r) to generate a 3D image of the far-field scene being illuminated by the 3D imaging sensor of the present disclosure. The (x, y, r) coordinates are calculated using a 2D fast Fourier transform of the reflectance density ρ, which is the reflection of the signal impinging on the target segment per infinitesimal volume dζdηdr. Thus, the reflectance density of the target can be modeled as a function of three variables (ζ, η,) as described below.

[0128] The image formation algorithm also makes adjustments for the resulting phase shift of the reflected transmit signal being reflected or backscattered by the far-field scene, the adjustments reducing or substantially eliminating the resulting phase shift experienced by the transmit signal after being emitted into the far-field scene by the energy emitting elements of the array, reflected or backscattered by the scene, and received by one or more energy detecting elements of the array.

[0129] In one embodiment, the value of the coordinate r associated with each adjusted set of coordinates (x,y) is also calculated by the image formation algorithm by performing a 2D FFT of the reflectivity density of the target from which the transmitted signal by the 3D imaging sensor is reflected. Thus, each calculated value of r for a particular (x,y) coordinate, i.e., r=R1, R2, R3, ..., R NFor x, y, R1, x, y, R2, there are corresponding voxels that can be calculated by the 3D imaging sensor of the present disclosure, thus generating a 3D image of the far-field scene. The coordinate r represents the distance between the corresponding energy detection element (the element that detects the reflected transmit signal) having coordinates (x, y) and a target point in the far-field scene that is illuminated by the transmit signal emitted by the array. The transmit signal is reflected (or backscattered) by the target point and detected by one or more energy detection elements of the array having coordinates of (x, y).

[0130] For that particular set of coordinates, the 3D imaging sensor of the present disclosure calculates r values ​​for different values ​​of r (r=R1, r=R2, r=R3, ...) in the course of generating a 3D image of the illuminated far-field scene. Thus, the resulting voxels have coordinates (x,y,R1), (x,y,R2), (x,y,R N ) where N is an integer of 1 or greater.

[0131] In one embodiment, the transmit signal includes a digital beamforming orthogonal digital waveform modulated by a MIMO processed frequency domain PN sequence (e.g., an orthogonal MIMO signal), which is converted to an analog waveform signal that modulates an energy source to provide a modulated signal that is then analog beamformed to obtain a transmit signal that is applied to one or more energy emitting elements of the array. The analog beamforming operation includes applying a signal directly to an element of the array to provide the element with a particular phase value. The phase of that element does not change until the signal (e.g., voltage, current) is no longer applied.

[0132] The receiver is configured to detect energy received by the energy detecting elements of the array, demodulate the received signal, and derive a baseband signal from the received signal. The receiver is further configured to perform operations, including computational imaging, on the received digital signal to generate one or more 3D images of an object, structure, or entire scene from which the transmitted signal is reflected. The object, structure, or other item in the far field scene is positioned relative to the array.

[0133] The computational imaging includes at least an image formation algorithm for adjusting for the resulting phase shift experienced by the reflected or backscattered transmit signal received by one or more energy detection elements of the array, and generating a 3D image of the received reflected or backscattered signal through the use of a 2D FFT performed on the signal. In particular, the received transmit signal is detected and demodulated to obtain a baseband signal. The signal is then converted to a digital signal by using an analog-to-digital converter. A 2D FFT operation is then performed on the digital signal to generate a 3D image of the far-field scene being illuminated by the 3D imaging sensor.

[0134] The 3D image is based on the illumination of a target location of an object, structure, or other item in the scene being illuminated. Obviously, each target location does not necessarily have the same distance. The distance between the energy detection elements of the array and the target location can vary, and in most cases it varies for different target locations. For example, the distance may be R for a first target location, then change to R1 for another location, and change to R2 for yet another location. The coordinates (x,y) and the calculated (r) coordinate become (x,y,r) coordinates representing a voxel (volume pixel) of the target 3D image of the object being illuminated by the transmission signal from the 3D imaging sensor of the present disclosure. Thus, a 3D image of the object is obtained.

[0135] FIG. 33 illustrates an exemplary imaging algorithm 3300 according to the present disclosure. The embodiment of the imaging algorithm 3300 illustrated in FIG. 33 is for illustrative purposes only. One or more of the components illustrated in FIG. 33 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0136] As shown in FIG. 33, a DFFT3302 is used to generate the output signal. In one embodiment of short-range imaging, for transmission, four-layer MIMO transmission is provided, and for reception, four-layer MIMO reception with subsequent range-dependent spatial processing with near-field imaging algorithms is provided as shown in the previous embodiment.

[0137] In one embodiment of mid-range imaging, for transmit, MIMO with beamforming transmit using two layers per beam is provided, and for receive, MIMO receive using two layers per beam followed by receive beamforming is provided.

[0138] In one embodiment of long range imaging, single layer transmit beamforming is provided for transmit, and single layer receive beamforming per beam is provided for receive.

[0139] In the present disclosure, a multi-stream transmission and reception scheme for high-resolution radar is provided. The present disclosure enables transmission and reception of signals in multiple beams in beamforming mode or multiple antennas in MIMO mode without interference between beams or antennas. The present disclosure reduces acquisition time by a factor of MxN, where M is the number of transmit beams (or MIMO layers) and N is the number of receive beams (or MIMO layers). The present disclosure provides an embodiment that can be applied to high-resolution imaging radar in automotive applications where a large number of channels and frame rates are required.

[0140] MIMO radar is promising for near-field imaging applications with large SINR. This disclosure enables a general image focusing algorithm after range / Doppler processing, enabling high-resolution images without artifacts.

[0141] For M=N=4, acquisition time can be reduced by a factor of 16 compared to the traditional approach of scanning analog Tx / Rx beams, or by a factor of 4 for multiple beams without 4-stream transmission.

[0142] Next-generation radar system technologies include new waveforms such as orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA), multiple-input multiple-output (MIMO) antennas with digital beamforming, 3D / 4D imaging, and simultaneous communications and radar.

[0143] Despite its simplicity, CDMA systems are well known to suffer from interference and multipath dispersion, and are susceptible to phase noise. The advantages of OFDM over frequency-modulated continuous wave (FM-CW) radar are well understood.

[0144] In such radar systems, waveform generation is simple, reducing transceiver complexity compared to FM-CW and chirp sequence modulation. In such radar systems, waveforms do not require linear frequency generation in hardware. In such radar systems, OFDM waveforms do not have strict phase noise requirements and are not susceptible to multipath interference, unlike phase modulated signals, which are susceptible to self-interference and multipath interference. In such radar systems, OFDM is ideally suited for MIMO processing.

[0145] Despite these advantages, generating and processing OFDM signals for high-resolution radar is difficult due to the wideband processing required for high-resolution radar. The signal bandwidth for 76 GHz to 81 GHz automotive radar is 1 GHz to 5 GHz, requiring analog-to-digital (ADC) rates exceeding 10 Gsps with a large number of bits.

[0146] A 12-bit 10Gsps ADC costs about $3,650. For 3D radar imaging, which requires tens or hundreds of channels, wideband OFDM radar systems are cost-prohibitive. Therefore, commercial radar transceivers rely on FMCW signals.

[0147] FIG. 34 illustrates an example power loss 3400 per transmit and receive path in a mmWave transceiver according to the present disclosure. The embodiment of the power loss 3400 per transmit and receive path in a mmWave transceiver illustrated in FIG. 34 is for illustrative purposes only. One or more of the components illustrated in FIG. 34 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0148] Another consideration is power consumption. A power consumption analysis of a state-of-the-art mmWave OFDM system is shown in Figure 34.

[0149] As shown in Figure 34, the power amplifier (PA) and radio frequency ADC (RF-ADC) account for 67% and 55% of the power loss in the transmit and receive paths, respectively. Low power PA and simpler ADC design are important in transceiver design. As shown in Figure 34, the power loss per transmit path (e.g., Figure 34(a)) and the power loss per receive path (e.g., Figure 34(b)) are provided.

[0150] In one embodiment, a scheme for sub-channel coded OFDM with aggregation is provided that retains the performance advantages of wideband OFDM systems while reducing the complexity associated with wideband signals for efficient multi-stream MIMO / beamforming radar, such as may be implemented by advanced systems.

[0151] In OFDM systems, the Fast Fourier Transform / Inverse Fast Fourier Transform (FFT / IFFT) must be performed in real time. For wideband radar with bandwidths up to 5 GHz, signals must be processed at sampling rates of 0.5 ns, 0.25 ns or better for high range resolution.

[0152] For automotive applications with a range of up to 300m, the range calculation needs to be done every 2μs. In the transmitter, the time domain signal can be pre-calculated for DAC and modulation, so real-time calculation can be no problem.

[0153] However, for the receiver, 4K and 8K FFT / IFFT and complex multiplications followed by CFAR detection are required for each path with 2GHz and 4GHz bandwidth, respectively. Although the receiver complexity is lower than that of time-domain PM radar, it imposes a significant computational burden on real-time implementation in state-of-the-art field programmable gate arrays (FPGAs) or application specific integrated circuits (ASICs).

[0154] In conventional radars, "stretch processing" is employed for range processing to reduce the signal processing requirements. "Stretch processing" uses a longer time window to sweep the radar bandwidth, slowing down the transmit / receiver processing operations. However, this approach is not applicable to automotive radars where the sequence length and required range are comparable. "Stretch processing" reduces the maximum range of the radar system.

[0155] In one embodiment, a computationally efficient receiver is provided utilizing CAZAC waveforms with cyclic correlation properties, reducing the computational complexity of range processing by more than 15 times for real-time implementation on FGPAs and ASICs.

[0156] FIG. 35A illustrates an exemplary 4D imaging radar 3500 according to the present disclosure. The embodiment of the 4D imaging radar 3500 illustrated in FIG. 35 is for illustrative purposes only. One or more of the components illustrated in FIG. 35 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0157] As shown in FIG. 35A, the imaging radar 3500 may be implemented as an advanced system, or the imaging radar 3500 may be implemented as one of the components of an advanced system.

[0158] As shown in FIG. 35A , the 4D imaging radar 3500 includes a PN sequence generation block 3502, a DFT block 3504, a MIMO codeword mapping block 3506, a layer mapping block 3508, a MIMO precoding block 3510, a set of RE mapping blocks 3512, a set of IFFT / CP blocks 3514, a digital BF Tx block 3516, a DAC block 3518, an energy source 3520, a modulator block 3522, a set of analog blocks 3524, a Tx and Rx antenna block 3526, an energy detection and demodulation block 3528, an ADC block 3530, an adder block 3532, a 2D It comprises an FFT block 3534 , an adder block 3536 , a complex conjugate block 3538 , a DFT block 3540 , an IFFT block 3542 , an arithmetic block 3544 , a threshold block 3546 , a post-processing block 3548 , a tracking block 3550 , and a lookup table block 3552 .

[0159] FIG. 35B illustrates an exemplary antenna array 3526 according to the present disclosure. The embodiment of the antenna array 3526 illustrated in FIG. 35B is for illustrative purposes only. One or more of the components illustrated in FIG. 35B may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0160] As shown in FIG. 35B, the antenna array 3526 includes a set of antenna arrays 3526A, 3526B.

[0161] The frame structure of a digital radar waveform is shown in Figure 24. A "slot" consists of a Cyclic Prefix (CP), multiple OFDM symbols generated by Discrete Fourier Transform (DFT) spreading of one or more CAZAC sequences, and a Guard Time (GT). GT is added based on the required sequence length and the target scene range of interest.

[0162] There are multiple sequence periods within a slot, each containing an OFDM symbol. The ranging process performs correlation of the received OFDM symbols against the transmitted coded signal, followed by coherent accumulation of the OFDM symbols within a slot.

[0163] The OFDM symbol length is determined as the inverse of the subcarrier spacing, while the slot length is set within the channel coherence time. As an example, for a 2 GHz RF bandwidth with a subcarrier spacing of 500 kHz, the FFT size is 4096 points, the OFDM symbol length is 2 μs, and the channel coherence time is 8 μs and 16 μs for speeds of 350 kmph and 175 kmph, respectively.

[0164] Multiple slots make up a subframe, which is used for Doppler processing. Each subframe signal illuminates targets within the antenna footprint (or beam in scanning radar) and causes reflections. Complete illumination of the target scene in the field of view results in a frame. The target scene is scanned multiple times, resulting in frame rates of 10 to 60 frames per second.

[0165] FIG. 36 illustrates an example overall transmit / receiver processing architecture 3600 according to the present disclosure. The embodiment of the overall transmit / receiver processing architecture 3600 illustrated in FIG. 36 is for illustrative purposes only. One or more of the components illustrated in FIG. 36 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0166] As shown in FIG. 36, the transmit / receiver processing architecture 3600 may be implemented as an advanced system, or the transmit / receiver processing architecture 3600 may be implemented as one of the components of an advanced system.

[0167] As shown in Figure 36, the transmit / receiver processing architecture 3600 includes a Tx antenna 3602, an Rx antenna 3604, an LPF 3606, 3610, an LO block 3608, a DAC block 3612, an ADC block 3620, an IFFT block 3614, an FFT block 3622, a subcarrier mapping block 3616, an element-wise operation block 3624, a DFT block 3618, a complex conjugate block 3626, an IFFT block 3628, and a slow-time FFT block 3630. The transmitter and receiver architectures for a DFT spread OFDM radar waveform are shown in Figure 36. The CAZAC sequence is transformed into a frequency domain signal with DFT. The frequency domain CAZAC sequence is mapped to a subcarrier centered on zero frequency and transformed back into a time domain signal. The DFT spread radar signal is converted to analog signal, passed to low pass filter (LPF) and IQ mixer (PA), and transmitted via Tx antenna. In the receiver, the signal from Rx antenna is demodulated and filtered, then converted to baseband signal by ADC.

[0168] The range processing is realized in the frequency domain, where the received baseband signal is transformed to the frequency domain by FFT and multiplied by the complex conjugate of the DFT version of the original CAZAC sequence, followed by a time domain transformation by IFFT, which gives the correlation output corresponding to each range bin.

[0169] Doppler processing is applied by taking the FFT of the correlation output for each range bin, resulting in a two-dimensional range-Doppler map.

[0170] In this embodiment, signals are pre-computed and stored in memory, thereby significantly reducing real-time processing requirements.

[0171] At the transmitter, the DFT-spread OFDM waveform after IFFT is pre-computed and stored in memory. For receiver processing, a reference signal, which is the complex conjugate of the DFT-spread CAZAC sequence, is pre-computed and stored in memory and used for range processing. Real-time processing is included in the receiver range and Doppler processing. Especially, range processing is the most difficult part in digital radar.

[0172] FIG. 37 illustrates an example frequency domain range Doppler processing 3700 of a radar waveform according to the present disclosure. The embodiment of the frequency domain range Doppler processing 3700 of a radar waveform illustrated in FIG. 37 is for illustrative purposes only. One or more of the components illustrated in FIG. 37 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0173] As shown in FIG. 37, the frequency domain range Doppler processing of radar waveforms 3700 may be implemented as an advanced system, or the frequency domain range Doppler processing of radar waveforms 3700 may be implemented as one of the components of an advanced system.

[0174] For OFDM systems, multiple correlation calculations are required for the symbols in a slot. Figure 37 shows a detailed block diagram of the range-Doppler processing of radar waveforms provided in this disclosure.

[0175] For automotive radar, the subcarrier spacing is determined by the two-way Doppler of the signal return. In a typical environment, the OFDM symbol length is 2 μs, and the number of OFDM symbols in a slot is set based on the channel coherence time, which can be 4 to 8. The FFT size is 4K and 8K for 2 GHz and 4 GHz RF bandwidths, respectively. In this signal structure, multiple FFT / complex multiplication / IFFT calculations are repeated for every 2 μs OFDM symbol. This results in a large number of gates and huge power consumption.

[0176] As shown in FIG. 37, the frequency domain range Doppler processing architecture includes a DFT block 3702, a subcarrier mapping block 3704, an IFFT block 3706, a repetition block 3708, a CP / GT insertion block 3710, a DAC block 3712, a complex conjugate block 3714, an ADC block 3716, a CP removal block 3718, an FFT block 3720, a complex multiplication block 3722, an IFFT block 3724, a Doppler DFT block 3726, a CFAR detector block 3728, and an arithmetic block 3730.

[0177] FIG. 38 illustrates an example time domain representation 3800 of compressed range processing of a transmit signal, a receive signal, a circular shift, and an add and subsequent accumulate operation according to the present disclosure. The embodiment of the time domain representation 3800 illustrated in FIG. 38 is for illustrative purposes only. One or more of the components illustrated in FIG. 38 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0178] In one embodiment, the linearity and periodic correlation properties of the signal are exploited to provide computationally efficient receiver processing (e.g., compressed range processing). Figure 38 shows the time domain signal processing of an OFDM slot in compressed range processing.

[0179] FIG. 38 shows a time domain representation of the compressed range process of the transmit signal, the receive signal, the circular shift, and the addition and subsequent accumulation operations. The receive signal entering the GT of a slot is circularly shifted by the length of the signal (N FFT x N symbol ), then the OFDM symbols in the slot are accumulated sample by sample.

[0180] As shown in FIG. 38, a transmitter 3802 transmits a CAZAC sequence, and a receiver 3804 receives the CAZAC sequence.

[0181] In such an embodiment of step 1, from the baseband receiver, the cyclic prefix is ​​removed from the received signal.

[0182] In such an embodiment of step 2, the last N FFT The samples are taken from the received signal falling within the guard time.

[0183] In such an embodiment of step 3, N FFT samples are added to the beginning of the signal.

[0184] In such an embodiment of step 4, the sample-by-sample accumulation of the OFDM symbols is performed within a slot.

[0185] In such an embodiment of step 5, the accumulated symbol length signal is N FFT It is transformed into the frequency domain for range processing.

[0186] FIG. 39 illustrates an example compressed range processing 3900 of a radar waveform according to the present disclosure. The embodiment of the compressed range processing 3900 of a radar waveform illustrated in FIG. 39 is for illustrative purposes only. One or more of the components illustrated in FIG. 39 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0187] As shown in FIG. 37, the compressed range processing 3900 of the radar waveform may be implemented as an advanced system, or the compressed range processing 3900 of the radar waveform may be implemented as one of the components of the advanced system.

[0188] As shown in FIG. 39, the ranging process operation includes a DFT block 3902 , a complex conjugate block 3904 , an IFFT block 3906 , a complex multiplication block 3908 , an FFT block 3910 , a symbol data summation block 3912 , and a circular shift and summation block 3914 .

[0189] A block diagram of the compressed range process is shown in FIG. Compressive range processing of the radar waveform is shown in Figure 39. The frequency domain correlation (FFT, complex multiplication and subsequent IFFT) is calculated once per slot instead of once per OFDM symbol.

[0190] In one embodiment, a reduction scheme is provided to reduce the complexity in two ways compared to conventional linear frequency domain correlation.

[0191] In one embodiment, by compressing multiple OFDM symbols into a single accumulated OFDM symbol, the processing time is reduced by N symbol while the complexity is N symbol is reduced by

[0192] In one example, one frequency domain correlation (eg, FFT / complex multiplication / IFFT) is required every 18 μsec instead of every 2 μsec.

[0193] 2xN needed for linear correlation FFT Instead of performing an FFT of N points, FFT A point-by-point FFT / complex multiplication / IFFT is required.

[0194] FIG. 40 illustrates an exemplary computational complexity 4000 of range processing according to the present disclosure. The embodiment of the computational complexity 4000 of range processing illustrated in FIG. 40 is for illustrative purposes only. One or more of the components illustrated in FIG. 40 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0195] FIG. 40 shows a comparison of the computational complexity between conventional frequency domain range processing and the compressed range processing provided in this disclosure.

[0196] Figure 40 shows a comparison of the computational complexity of range processing, which shows a 16-fold reduction in complexity compared to the common frequency domain approach (time domain processing requires 134,217,728 multiplications and 536,870,912 multiplications for slot range processing, which requires 1000 times more complex multiplication-additions compared to the proposed approach).

[0197] Table 1 shows the system parameters for performance evaluation. The RF bandwidth is assumed to be 2 GHz.

[0198] FIG. 41 illustrates an exemplary decision statistic 4100 after range processing of an AWGN channel according to the present disclosure. The embodiment of the decision statistic 4100 after range processing of an AWGN channel illustrated in FIG. 41 is for illustrative purposes only. One or more of the components illustrated in FIG. 41 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0199] [Table 1]

[0200] FIG. 42 illustrates an example slice 4200 of decision statistics after range-Doppler processing of an AWGN channel according to the present disclosure. The embodiment of the slice 4200 of decision statistics after range processing of an AWGN channel illustrated in FIG. 42 is for illustrative purposes only. One or more of the components illustrated in FIG. 42 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0201] Figure 42 shows the results after range processing, calculated using the compressed range processing provided in this disclosure. The average range sidelobes are approximately -34 dB relative to the signal peak.

[0202] FIG. 42 shows a slice of the signal after range-Doppler processing according to the compressive range processing algorithm provided in this disclosure. Range and Doppler slices are shown in the top and bottom plots. The peak and average range side lobes are approximately -50 dB and -58 dB, respectively. The peak and average Doppler side lobes are -50 dB and -62 dB, respectively.

[0203] FIG. 43 illustrates an example 2D range Doppler map after range Doppler processing 4300 according to the present disclosure. The embodiment of the 2D range Doppler map after range Doppler processing 4300 shown in FIG. 43 is for illustrative purposes only. One or more of the components shown in FIG. 43 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0204] FIG. 43 shows a two-dimensional range-Doppler map after compressed range processing and subsequent Doppler processing, which shows the sharp range-Doppler uncertainty function required for high resolution radar.

[0205] The compressed range processing provided in this disclosure cyclically adds data from the GT to the first symbol of the received signal. The addition causes the noise variance of the resulting signal to be N symbol· s 2 From (N symbol +1)s 2 s 2 is the noise variance of the received complex baseband signal, 1 / N symbol For the analyzed system parameters, this is 0.5 dB, resulting in a decrease in SINR by 0.5 dB.

[0206] In this disclosure, a computationally efficient radar receiver architecture is provided for real-time implementation of OFDM radar using CAZAC sequence coding. The compressed range processing provided in this disclosure uses cyclic addition and symbol accumulation processing, resulting in significantly reduced complex FFT / complex multiplication / IFFT processing for efficient real-time implementation using state-of-the-art FPGA / DSP hardware or low-power, low-complexity ASIC implementation.

[0207] In the aforementioned embodiments, the complexity is reduced by up to a factor of 16 compared to state-of-the-art efficient frequency domain range processing algorithms.Computational complexity is saved by a factor of over 1000 compared to time domain processing from conventional PM radar.

[0208] This disclosure can be directly applied to 4D imaging radar with MIMO and beamforming by processing per channel at the receiver. This disclosure can be applied to time-domain radar codes such as PM coded radar as long as the underlying PM radar waveforms have a similar frame structure and the codes have cyclic correlation properties.

[0209] In one embodiment of the present disclosure, a 3D imaging sensor comprises a transmitter, a receiver, and an array coupled to the transmitter and receiver, the array having one or more energy emitting elements and energy detecting elements, and the array configured to emit a transmit signal generated by the transmitter.

[0210] In such an embodiment, the transmit signal includes a digital beamformed orthogonal digital waveform modulated by a MIMO processed frequency domain PN sequence, the digital beamformed orthogonal digital waveform is converted to an analog waveform signal that modulates an energy source to provide a modulated signal (i.e., modulated energy), and the modulated signal is analog beamformed to obtain a transmit signal that is applied to one or more energy emitting elements of the array.

[0211] The receiver is configured to perform operations using computational imaging including at least an image formation algorithm to generate a 3D image of a far-field scene illuminated by the 3D imaging sensor of the present disclosure. The image formation algorithm first adjusts for a resultant phase shift experienced by a signal transmitted from the 3D imaging sensor and reflected or backscattered by the far-field scene. Furthermore, the image formation algorithm performs a 2D FFT (Fast Fourier Transform) of the reflection density of the reflected signal to generate a 3D image of the scene from which the transmitted signal is reflected or backscattered.

[0212] Referring now to Figure 35, another embodiment of the present disclosure is shown. Although not shown, the embodiment of Figure 35 may also be operated, controlled, or otherwise directed by a processor in a manner similar to the embodiments of the present disclosure. That is, the processor control of the embodiment of Figure 35 includes a master processor that controls one or more processors including a microprocessor, a microcontroller, a digital signal processor (DSP), or a processor implemented as or part of a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or other similar circuit. Furthermore, the processor may reside on a circuit board that forms part of the image sensor, or the processor may be located remotely while still being able to operate, control, or otherwise direct any of the modules of Figure 35.

[0213] In the embodiment of FIG. 35, the 3D imaging sensor 3500 comprises a transmitter (including modules 3502-3502A), a receiver (including modules 3524B-3552), and an array 3526 coupled to the transmitter and receiver, the array 3526 having one or more energy emitting elements and energy detecting elements, and the array 3526 configured to emit a transmit signal generated by the transmitter.

[0214] The array 3526 of FIG. 35 is configured to emit energy in various frequency bands or regions and / or wavelength ranges. For example, the array 3526 of FIG. 35 is configured to emit or detect optical signals in the near infrared (NIR) wavelength range of 700 nm to 1400 nm, inclusive, and the shortwave infrared (SWIR) wavelength range of 1400 nm to 3000 nm, inclusive. The array 3526 is also configured to emit or detect electromagnetic signals in one of the high frequency (HF) region or band, the very high frequency (VHF) region, the ultra high frequency (UHF), the centimeter wave (SHF) band, the millimeter wave (EHF) region, and the terahertz (THz) region. The EHF region is particularly suitable for simultaneous broadband communication and high resolution imaging. The terms "frequency region" and "frequency band" are used interchangeably.

[0215] A front view of the array 3526 is shown in FIG. 35, showing the array 3526 including four subarrays 3526A, 3526B, 3526C, and 3526D. In general, the array 3526 can be subdivided into any number of subarrays, with each subarray including a certain number of array elements. Each subarray can have the same number of array energy emitting and energy detecting elements. Also, a particular subarray may have a different number of elements depending on the location of said subarray within the overall array. For example, a subarray at or near the center of the array may include more array elements than any other subarray.

[0216] The transmit signal includes digitally beamformed orthogonal digital waveforms (the output of the digital beamformer Tx 3516). Before being digitally beamformed, the orthogonal digital waveforms are passed through a corresponding Inverse Fast Fourier Transform (IFFT) Cyclic Prefix (CP) module 3514. 1, ...,3514 L The resource element (RE) mapping modules 35121,...,3512 are coupled to LThe orthogonal digital waveform is generated by a combination of the digital beamformer 3516 and the digital beamformer 3516. The orthogonal digital waveform is modulated by a multiple-input multiple-output (MIMO) processed frequency domain pseudo-noise (PN) sequence (output of the MIMO precoding module 3510). Thus, the digital beamformed orthogonal digital waveform is obtained by applying the orthogonal digital waveform to the digital beamformer 3516.

[0217] The digital beamforming quadrature digital waveforms are converted to analog waveforms by the DAC 3518 (i.e., the signal at the output of the DAC 3518). The resulting analog waveform is applied to the input of the modulator 3522 module to modulate the energy source 3520, resulting in a modulated analog signal that is an analog beam formed by the beamformer 3524A to obtain a transmit signal (output of the analog beamformer 3524A) that is applied to one or more energy emitting elements of the array. The one or more energy emitting elements of the array 3526 emit the transmit signal that is applied to them.

[0218] The modulator 3522 of FIG. 35 may be configured as any one of a binary phase shift keying (BPSK) modulator, a quadrature phase shift keying (QPSK) modulator, an on-off keying (OOK) modulator, an amplitude shift keying (ASK) modulator, a frequency shift keying (FSK) modulator, a pulse position modulation (PPM) modulator, a phase shift keying (PSK) modulator, and a differential phase shift keying (DPSK) modulator.

[0219] Continuing to refer to FIG. 35, production of the transmit signal begins with a PN sequence generator 3502, which generates a time domain PN sequence S 0, S1,S2,...,S N-1 , which is then transformed via a Discrete Fourier Transform (DFT) module 3504 into a frequency domain PN sequence X 0, X 1, X 2, ..., X N-1 is converted to

[0220] The DFT module 3504 is a circuit or module that performs a discrete Fourier transform on a time domain sequence to convert the sequence into a frequency domain sequence. A time domain PN sequence derived from a CAZAC sequence is one example of a PN sequence generated by the PN sequence generator 3502. A CAZAC sequence is a type of PN sequence that has a constant amplitude zero autocorrelation (CAZAC) property. The u-th root of a Zadoff-Chu sequence, which is a CAZAC sequence, is given by the formula:

[0221]

number

[0222] where N ZC is the length of the Zadoff-Chu sequence. Then, the frequency domain PN sequence is MIMO processed.

[0223] FIG. 44 illustrates a flowchart of a method 4400 for multi-stream MIMO / beamforming radar according to the present disclosure that may be performed by an advanced system (e.g., 101-103 and / or 111-116, as shown in FIG. 1). The embodiment of method 4400 illustrated in FIG. 44 is for illustrative purposes only. One or more of the components illustrated in FIG. 44 may be implemented in specialized circuitry configured to perform the described functions, or one or more of the components may be implemented by one or more processors executing instructions to perform the described functions. Other embodiments may be used without departing from the scope of the present disclosure.

[0224] As shown in Figure 44, the method 4400 begins in step 4402. In step 4402, the advanced system identifies a set of orthogonal multiple-input multiple-output (MIMO) signals.

[0225] Next, in step 4404, the advanced system generates a first set of beams.

[0226] Next, in step 4406, the advanced system maps a set of orthogonal MIMO signals to each of the set of generated beams.

[0227] Next, in step 4408, the advanced system transmits a first signal based on the first set of beams to the target scene.

[0228] Finally, in step 4410, the advanced system receives a second signal based on a second set of beams reflected or backscattered from the target scene.

[0229] In one embodiment, the advanced system generates a set of orthogonal MIMO signals including a set of CAZAC sequences based on a set of circularly shifted CAZAC sequences.

[0230] In one embodiment, the advanced system generates a set of orthogonal MIMO signals, including a set of MIMO coded signals, based on a set of different root CAZAC sequences.

[0231] In one embodiment, the advanced system identifies a set of reference signal candidates and calculates correlations for the set of reference signal candidates.

[0232] In one embodiment, the advanced system uses a set of orthogonal MIMO signals to illuminate the entire scene with the same transmit beam of a first beam set.

[0233] In one embodiment, the advanced system uses a range / Doppler process calculated on a set of orthogonal MIMO signals to identify the signals, and performs spatial processes on the identified signals to generate an image.

[0234] In one embodiment, the advanced system identifies an operating mode including a MIMO operating mode, a hybrid of MIMO and beamforming operating modes, or a beamforming operating mode based on the target range, transmits a first signal based on the identified operating mode, and receives a second signal based on the identified operating mode.

[0235] In one embodiment, the advanced system constructs a signal corresponding to an Orthogonal Frequency Division Multiplexing (OFDM) radar waveform that repeats a set of OFDM symbols, accumulates the set of OFDM symbols in a slot using a same code across multiple symbols of the set of OFDM symbols, generates a composite signal based on the accumulated set of OFDM symbols, and calculates a range correlation of the generated composite signal.

[0236] In such an embodiment, the advanced system calculates the range correlation based on calculating an FFT of the composite signal, calculating a complex multiplication of the composite signal and a reference signal, and calculating an IFFT of the calculated complex multiplied composite signal to obtain the range correlation.

[0237] It may be advantageous to explain definitions of certain words and phrases used throughout this patent document. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or portions thereof adapted for implementation in suitable computer code (including source code, object code, or executable code). The term "communication" and its derivatives encompass both direct and indirect communication. The terms "comprise" and "comprise" and their derivatives mean inclusion without limitation. The term "or" is inclusive and / or. The phrase "associated with" and its derivatives may mean including, contained within, interconnected with, containing, contained within, connected to or with, coupled to or with, communicable with, cooperate with, interleave with, juxtapose with, in close proximity to, bound to or with, having, having the property of, having a relationship to or with, and the like. The phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one item in the list may be required. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A, B, and C.

[0238] Although the present disclosure has described certain embodiments and generally related methods, modifications and permutations of these embodiments and methods will be apparent to those skilled in the art. Thus, the above description of exemplary embodiments does not define or limit the present disclosure. Other modifications, substitutions, and alterations are possible without departing from the scope of the present disclosure, as defined by the appended claims.

Claims

1. A system comprising: a set of antennas including a set of transmit antennas and a set of receive antennas; Digital beamformer and a processor operatively connected to the set of antennas and to the digital beamformer; The processor, Identifying a set of orthogonal multiple-input multiple-output (MIMO) signals; generating a first set of beams via the digital beamformer; configured to map the set of orthogonal MIMO signals to each of the set of generated beams; The system comprises: a transceiver operably connected to the processor; The transceiver includes: transmitting a first signal based on the first set of beams to a target scene via the set of transmit antennas of the set of antennas; configured to receive, via the set of receive antennas of the set of antennas, a second signal based on a second set of beams reflected or backscattered from the target scene; The system, wherein the processor is further configured to generate the set of orthogonal MIMO signals comprising a set of MIMO coded signals based on a set of different root CAZAC sequences.

2. A system comprising: a set of antennas including a set of transmit antennas and a set of receive antennas; Digital beamformer and a processor operatively connected to the set of antennas and to the digital beamformer; The processor, Identifying a set of orthogonal multiple-input multiple-output (MIMO) signals; generating a first set of beams via the digital beamformer; configured to map the set of orthogonal MIMO signals to each of the set of generated beams; The system comprises: a transceiver operably connected to the processor; The transceiver includes: transmitting a first signal based on the first set of beams to a target scene via the set of transmit antennas of the set of antennas; configured to receive, via the set of receive antennas of the set of antennas, a second signal based on a second set of beams reflected or backscattered from the target scene; The system, wherein the transceiver is further configured to illuminate an entire scene with a same transmit beam of the first set of beams using the set of orthogonal MIMO signals.

3. A system comprising: a set of antennas including a set of transmit antennas and a set of receive antennas; Digital beamformer and a processor operatively connected to the set of antennas and to the digital beamformer; The processor, Identifying a set of orthogonal multiple-input multiple-output (MIMO) signals; generating a first set of beams via the digital beamformer; configured to map the set of orthogonal MIMO signals to each of the set of generated beams; The system comprises: a transceiver operably connected to the processor; The transceiver includes: transmitting a first signal based on the first set of beams to a target scene via the set of transmit antennas of the set of antennas; configured to receive, via the set of receive antennas of the set of antennas, a second signal based on a second set of beams reflected or backscattered from the target scene; The processor, Identifying an operating mode including a MIMO operating mode, a hybrid of a MIMO and a beamforming operating mode, or a beamforming operating mode based on the target range; Transmitting the first signal based on the identified mode of operation; The system is further configured to receive the second signal based on the identified operational mode.

4. A system comprising: a set of antennas including a set of transmit antennas and a set of receive antennas; Digital beamformer and a processor operatively connected to the set of antennas and to the digital beamformer; The processor, Identifying a set of orthogonal multiple-input multiple-output (MIMO) signals; generating a first set of beams via the digital beamformer; configured to map the set of orthogonal MIMO signals to each of the set of generated beams; The system comprises: a transceiver operably connected to the processor; The transceiver includes: transmitting a first signal based on the first set of beams to a target scene via the set of transmit antennas of the set of antennas; configured to receive, via the set of receive antennas of the set of antennas, a second signal based on a second set of beams reflected or backscattered from the target scene; The processor, Constructing a signal corresponding to an orthogonal frequency division multiplexing (OFDM) radar waveform that repeats a set of OFDM symbols; accumulating the set of OFDM symbols into a slot using the same code across multiple symbols of the set of OFDM symbols; generating a composite signal based on the accumulated set of OFDM symbols; the system is further configured to calculate a range correlation for the generated composite signal based on calculating an FFT of the composite signal, calculating a complex multiplication of the composite signal and a reference signal, and calculating an IFFT of the calculated complex multiplied composite signal to obtain a range correlation.

5. The system of any one of claims 2 to 4, wherein the processor is further configured to generate the set of orthogonal MIMO signals comprising a set of CAZAC sequences based on a set of circularly shifted CAZAC sequences.

6. The processor, Identifying a set of candidate reference signals; The system of any one of claims 1 to 5, further configured to calculate correlations of the set of reference signal candidates.

7. The processor, identifying signals using a range / Doppler process calculated for the set of orthogonal MIMO signals; The system of any one of claims 1 to 6, further configured to perform a spatial process on the identified signals to generate an image.

8. A method of a system comprising: Identifying a set of orthogonal multiple-input multiple-output (MIMO) signals; generating a first set of beams; mapping the set of orthogonal MIMO signals onto each of the set of generated beams; transmitting a first signal based on the first set of beams into a target scene; receiving a second signal based on a second set of beams reflected or backscattered from the target scene; generating the set of orthogonal MIMO signals, the set comprising a set of MIMO coded signals, based on a set of different root CAZAC sequences.

9. A method of a system comprising: Identifying a set of orthogonal multiple-input multiple-output (MIMO) signals; generating a first set of beams; mapping the set of orthogonal MIMO signals onto each of the set of generated beams; transmitting a first signal based on the first set of beams into a target scene; receiving a second signal based on a second set of beams reflected or backscattered from the target scene; and illuminating an entire scene with a same transmit beam of the first set of beams using the set of orthogonal MIMO signals.

10. identifying signals using a range / Doppler process calculated for the set of orthogonal MIMO signals; performing a spatial process on the identified signals to generate an image; The method of claim 9 further comprising:

11. A system and method comprising: Identifying a set of orthogonal multiple-input multiple-output (MIMO) signals; generating a first set of beams; mapping the set of orthogonal MIMO signals onto each of the set of generated beams; transmitting a first signal based on the first set of beams into a target scene; receiving a second signal based on a second set of beams reflected or backscattered from the target scene; identifying an operating mode including a MIMO operating mode, a hybrid of a MIMO and a beamforming operating mode, or a beamforming operating mode based on the target range; transmitting the first signal based on the identified mode of operation; receiving the second signal based on the identified mode of operation.

12. A system and method comprising: Identifying a set of orthogonal multiple-input multiple-output (MIMO) signals; generating a first set of beams; mapping the set of orthogonal MIMO signals onto each of the set of generated beams; transmitting a first signal based on the first set of beams into a target scene; receiving a second signal based on a second set of beams reflected or backscattered from the target scene; constructing a signal corresponding to an orthogonal frequency division multiplexing (OFDM) radar waveform that repeats a set of OFDM symbols; accumulating the set of OFDM symbols into a slot using the same code across multiple symbols of the set of OFDM symbols; generating a composite signal based on the accumulated set of OFDM symbols; calculating a range correlation for the generated composite signal based on calculating an FFT of the composite signal, calculating a complex multiplication of the composite signal and a reference signal, and calculating an IFFT of the calculated complex multiplied composite signal to obtain a range correlation.

13. The method of any one of claims 9 to 12, further comprising generating the set of orthogonal MIMO signals comprising a set of CAZAC sequences based on a set of circularly shifted CAZAC sequences.

14. identifying a set of candidate reference signals; calculating correlations of the set of candidate reference signals; The method of any one of claims 8 to 13, further comprising:

15. A program for causing a computer to execute the method according to any one of claims 8 to 14.

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