Method and apparatus for coordinated radar system

Abstract

The apparatus (116) include: a transmitter (1000), a receiver (1100) operably coupled to the transmitter (1000), the receiver (1100) configured to receive, from at least one apparatus (103) including a second apparatus (102), signals; and at least one processor (225) operably coupled to the transmitter (1000) and the receiver (1100), the at least one processor (225) configured to: identify a time stamp embedded in each signal of the signals received from the at least one apparatus (103), identify a location of each apparatus (103) of the at least one apparatus (103), and adjust, based on the location of each apparatus (103), the time stamp of each apparatus (103), wherein the transmitter (1000) is configured to transmit, to the at least one apparatus (103), a signal including the adjusted time stamp.

Description

METHOD AND APPARATUS FOR COORDINATED RADAR SYSTEMTECHNICAL FIELD

[0001] This disclosure generally relates to a radar system. More specifically, this disclosure relates to a coordinated radar system.BACKGROUND

[0002] After the invention of the merging radar in 1904, numerous technologies break-through occurred over the past 100 years, such as FM continuous-wave (FMCW) radar, chirp radar and synthetic aperture radar. They have been used in mission-critical applications in military and space for surveillance and / or navigation. From the 1970’s, civilian applications followed such as spacebome synthetic aperture radar (SAR), search and rescue operations and automotive.

[0003] From the 1990’s, mobile communication technologies saw break-through, resulting in ubiquitous mobile communication coverage and the availability of low -cost mobile devices connecting people in the world. A number of mobile subscribers in the world is expected to exceed 5 billion people, while mobile user penetration already exceeded 62.9% in Y2016.

[0004] As emerging with 5thgeneration (5G) and 6thgeneration (6G) system connecting the world, a major paradigm shift is occurring in a communication system. The most important change is connectivity for all things mobile. This in turn may enable automation foreseen by “Industry 4.0” by analyzing massive amount of data generated by “intelligent” sensors, wideband, low-latency 5G / 6G connectivity, edge computing, and the management software located in an enterprise data center.

[0005] Sensors, in particular radar and Lidar are becoming an integral part of any automation, including automotive safety advanced driver assistance system (ADAS) systems and autonomous vehicle (AV) systems, perimeter security, 5G / 6G smart city, intelligent transportation systems, robotics, remote surgery, and smart factory. These sensors provide high-resolution and high-performance sensing such as three- dimensional (3D) images for computer vision. These sensors may provide massive amounts of real-time data and intelligence, providing insights analyzed by machine learning software located at the edge of the network. High-resolution imaging radars are becoming essential for machine perception in all environmental conditions, such as outdoor harsh environment.

[0006] A digital radar waveform brings performance that was not imaginable with an analog waveform in machine perception. The waveform is shaped to provide a low sidelobe level, a sharp range, Doppler resolution, and co-channel interference immunity from other radar users and intentional jamming signal.

[0007] Major challenge in a high-resolution radar waveform is its implementation complexity. In an FMCW radar, a stretch processing is an innovative way to reduce processing bandwidth of the signal. The resolution of range processing is determined by the bandwidth of the signal, which can be multi-GHz. In practical systems, the digital processing is limited by the sampling rate of the analog-to-digital converters (ADCs).

[0008] Phase modulation (PM) radars and orthogonal frequency division multiplexing (OFDM) radarsbased on a wide bandwidth signal may require a wideband and high bit-rate ADC. For a high-resolution imaging radar, many RF channels are required, driving the cost and power consumption of the system. Furthermore, a digital signal processing may need to be done at Nyquist rate of the signal, making the receiver processing challenging, even in today’s computation technology. OFDM signal generation and processing are challenging due to the wide bandwidth processing required for high-resolution radars. Automotive radars in 76GHz-81GHz has signal bandwidth of 1GHz to 5GHz, requiring ADC rate exceeding lOGsps with large number of bits. A 12-bit lOGsps ADC is $3,650. For 3D radar imaging requiring 10’s to 100’s channels, wideband OFDM radar systems are not practical. As such, commercially available radar transceivers rely on FMCW signal.

[0009] In the present disclosure, global positioning system (GPS) free synchronization based on masterslave is provided, sync channel design based on low bandwidth version of radar (same as above) is provided, and a cooperative transmission and reception of the signal to form high resolution is provided.

[0010] In one embodiment, the use of time of flight for getting accurate relative location between the vehicles is provided.

[0011] In one embodiment, an operation on synchronization and communications for non-vehicle applications (e.g., for home or industrial) is provided.

[0012] In one embodiment, a synchronization method for automotive applications is provided.

[0013] In one embodiment, implementations technologies for home or industrial applications are provided.SUMMARY

[0014] This disclosure provides a coordinated radar system.

[0015] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.

[0016] In one embodiment, a first apparatus is provided. The first apparatus comprises a transmitter and a receiver operably coupled to the transmitter, the receiver configured to receive, from at least one apparatus including a second apparatus, signals. The first apparatus further comprises at least one processor operably coupled to the transmitter and the receiver, the at least one processor configured to: identify a time stamp embedded in each signal of the signals received from the at least one apparatus, identify a location of each apparatus of the at least one apparatus, and adjust, based on the location of each apparatus, the time stamp of each apparatus, wherein the transmitter is configured to transmit, to the at least one apparatus, a signal including the adjusted time stamp.

[0017] In another embodiment, a second apparatus is provided. The second apparatus comprises a receiver and at least one processor operably coupled to the receiver, the at least one processor configured to: generate a time stamp, and embed the time stamp into a signal. The second apparatus further comprises a transmitter operably coupled to the receiver and the at least one processor, the transmitter configured to: transmit, to a first apparatus, the signal including the time stamp, and receive, from the first apparatus, a corresponding signal including an adjusted time stamp, wherein a location of the second apparatus is identified and the adjusted time stamp is identified based on the location of the second apparatus.

[0018] In yet another embodiment, a method of a first apparatus is provided. The method comprises: receiving, from at least one apparatus including a second apparatus, signals; identifying a time stamp embedded in each signal of the signals received from the at least one apparatus; identifying a location of each apparatus of the at least one apparatus; adjusting, based on the location of each apparatus, the time stamp of each apparatus; and transmitting, to the at least one apparatus, a signal including the adjusted time stamp.

[0019] Since it requires wideband signal for high resolution radar system, methods of cost effective implementations using band-pass sampling and sub-band signal processing are provided.

[0020] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.

[0021] Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term “couple” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with one another. The terms “transmit,” “receive,” and “communicate,” as well as derivatives thereof, encompass both direct and indirect communication. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and / or. The phrase “associated with,” as well as derivatives thereof, means to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, have a relationship to or with, or the like. The term “controller” means 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 and 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 only one item in the list may be needed. 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 and B and C.

[0022] Moreover, various functions described below can 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, sets of instructions, procedures, functions, objects, classes, instances, related data, or a portion thereof adapted for implementation in a suitable computer readable program code. The phrase “computer readable program code” includes any type of computer code, including source code, object code, and executable code. The phrase “computer readable medium” includes any type of medium capable of being accessed by a computer, such as read only memory (ROM), random access memory (RAM), a hard disk drive, a compact disc (CD), a digital video disc (DVD), or any other type of memory. A “non-transitory” computer readable medium excludes wired, wireless, optical, or other communication links that transport transitory electrical or other signals. A non-transitory computer readable mediumincludes media where data can be permanently stored and media where data can be stored and later overwritten, such as a rewritable optical disc or an erasable memory device.

[0023] Definitions for other certain words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many if not most instances, such definitions apply to prior as well as future uses of such defined words and phrases.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] For a more complete understanding of this disclosure, reference is made to the following description, taken in conjunction with the accompanying drawings, in which:

[0025] FIGURE 1 illustrates an example wireless network in accordance with various embodiments of the present disclosure;

[0026] FIGURE 2 illustrates an example gNB according to various embodiments of the present disclosure;

[0027] FIGURE 3 illustrates an example UE according to various embodiments of the present disclosure;

[0028] FIGURE 4 illustrates an example of functional blocks per vehicle according to various embodiments of the present disclosure;

[0029] FIGURE 5 illustrates an example of cluster for a radar system according to various embodiments of the present disclosure;

[0030] FIGURE 6 illustrates another example of cluster for a radar system according to various embodiments of the present disclosure;

[0031] FIGURE 7 illustrates an example time-domain signal format according to various embodiments of the present disclosure;

[0032] FIGURE 8 illustrates an example of cluster processing according to various embodiments of the present disclosure;

[0033] FIGURE 9 illustrates an example transmitter architecture for sub-band coded OFDM radar with bandpass sampling according to various embodiments of the present disclosure;

[0034] FIGURE 10 illustrates an example transmitter architecture for multi-channel coded OFDM system according to various embodiments of the present disclosure;

[0035] FIGURE 11 illustrates an example receiver architecture for multi-channel coded OFDM radar system according to various embodiments of the present disclosure; and

[0036] FIGURE 12 illustrates a flowchart of a method for a coordinated radar system according to various embodiments of the present disclosure.DETAILED DESCRIPTION

[0037] FIGURES 1 through 12, described below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any type of suitably arranged device or system.

[0038] FIGURE 1 illustrates an example wireless network according to various embodiments of the presentdisclosure. The embodiment of the wireless network shown in FIGURE 1 is for illustration only. Other embodiments of the wireless network 100 could be used without departing from the scope of this disclosure.

[0039] As shown in FIGURE 1, the wireless network includes a gNB 101, a gNB 102, and a gNB 103. The gNB 101 communicates with the gNB 102 and the gNB 103. The gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0040] The gNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipment (UEs) within a coverage area 120 of the gNB 102. The first plurality of UEs includes a UE 111, which may be located in a small business (SB); a UE 112, which may be located in an enterprise (E); a UE 113, which may be located in a WiFi hotspot (HS); a UE 114, which may be located in a first residence (R); a UE 115, which may be located in a second residence (R); and a UE 116, which may be a mobile device (M), such as a cell phone, a wireless laptop, a wireless PDA, or the like. The gNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a 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 of the gNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G, LTE, LTE- A, WiMAX, WiFi, or other wireless communication techniques.

[0041] In the present disclosure, a UE or a gNB as illustrated in FIGURE 1 may be implemented as a radar system as a stand-alone system or included in a vehicle. FIGURE 1 illustrates an example of implementation of the provided technologies for a network architecture including a radar system provided in the present disclosure.

[0042] Depending on the network type, the term “base station” or “BS” can refer to any component (or collection of components) configured to provide wireless access to a network, such as transmit point (TP), 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 wirelessly enabled devices. Base stations may provide wireless access in accordance with one or more wireless communication protocols, e.g., 5G 3GPP new radio 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 the sake of convenience, the terms “BS” and “TRP” are used interchangeably in this patent document 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” can refer to any component such as “mobile station,” “subscriber station,” “remote terminal,” “wireless terminal,” “receive point,” or “user device.” For the sake of convenience, the terms “user equipment” and “UE” are used in this patent document to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or vending machine).

[0043] Dotted lines show the approximate extents of the coverage areas 120 and 125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, may have othershapes, including irregular shapes, depending upon the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstructions.

[0044] As described in more detail below, one or more of the UEs 111-116 include circuitry, programing, or a combination thereof, for reception reliability for data and control information in an advanced wireless communication system. In certain embodiments, and one or more of the gNBs 101-103 includes circuitry, programing, or a combination thereof, for a bandpass sampled software -defined radio in next generation radar systems.

[0045] Although FIGURE 1 illustrates one example of a wireless network, various changes may be made to FIGURE 1. For example, the wireless network could include any number of gNBs and any number of UEs in any suitable arrangement. Also, the gNB 101 could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network 130. Similarly, each gNB 102-103 could communicate directly with the network 130 and provide UEs with direct wireless broadband access to the network 130. Further, the gNBs 101, 102, and / or 103 could provide access to other or additional external networks, such as external telephone networks or other types of data networks.

[0046] FIGURE 2 illustrates an example gNB 102 according to various embodiments of the present disclosure. The embodiment of the gNB 102 illustrated in FIGURE 2 is for illustration only, and the gNBs 101 and 103 of FIGURE 1 could have the same or similar configuration. However, gNBs come in a wide variety of configurations, and FIGURE 2 does not limit the scope of this disclosure to any particular implementation of a gNB. As illustrated in FIGURE 2, a radar system provided in the present disclosure can be implemented as a component of the gNB 102 or a stand-alone system on behalf of the gNB 102. FIGURE 2 does not limit the implementation technologies of the radar system provided in the present disclosure.

[0047] As shown in FIGURE 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.

[0048] The TX processing circuitry 215 receives analog or digital data (such as voice data, web data, e- mail, or interactive video game data) from the controller / processor 225. The TX processing circuitry 215 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate processed baseband or IF signals. The RF transceivers 210a-210n receive the outgoing processed baseband or IF signals from the TX processing circuitry 215 and up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 205a-205n.

[0049] The RF transceivers 210a-210n receive, from the antennas 205a-205n, incoming RF signals, such as signals reflected by UEs or any other objects in the network 100. 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 the baseband or IF signals and / or decompressing or correlating. The RX processing circuitry 220sends the processed baseband signals to the controller / processor 225 for further processing.

[0050] The controller / processor 225 can include one or more processors or other processing devices that control the overall operation of the gNB 102. For example, the controller / processor 225 could 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 could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller / processor 225 could support beam forming 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 could be supported in the gNB 102 by the controller / processor 225.

[0051] The controller / processor 225 is also capable of executing programs and other processes resident in the memory 230, such as an OS. The controller / processor 225 can move data into or out of the memory 230 as required by an executing process.

[0052] The controller / processor 225 is also coupled to the backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. The interface 235 could support communications over any suitable wired or wireless connection(s). For example, when the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G, LTE, or LTE-A), the interface 235 could allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 could allow 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 communications over a wired or wireless connection, such as an Ethernet or RF transceiver.

[0053] The memory 230 is coupled to the controller / processor 225. Part of the memory 230 could include a RAM, and another part of the memory 230 could include a Flash memory or other ROM.

[0054] Although FIGURE 2 illustrates one example of gNB 102, various changes may be made to FIGURE 2. For example, the gNB 102 could include any number of each component shown in FIGURE 2. As a particular example, the ground station could include a number of interfaces 235, and the controller / processor 225 could support routing functions to route data between different network addresses. As another particular example, while shown as including a single instance of TX processing circuitry 215 and a single instance of RX processing circuitry 220, the gNB 102 could include multiple instances of each (such as one per RF transceiver). Also, various components in FIGURE 2 could be combined, further subdivided, or omitted and additional components could be added according to particular needs.

[0055] As illustrated in FIGURE 2, all of components illustrated in FIGURE 2 may be implemented in a radar system provided in the present disclosure.

[0056] FIGURE 3 illustrates an example UE 116 according to various embodiments of the present disclosure. The embodiment of the UE 116 illustrated in FIGURE 3 is for illustration only, and the UEs111-115 of FIGURE 1 could have the same or similar configuration. However, UEs come in a wide variety of configurations, and FIGURE 3 does not limit the scope of this disclosure to any particular implementation of a UE.

[0057] An advanced communication apparatus may refer to a transmitter or receiver array providing hybrid beamforming operation based on all functional blocks, and may be implemented in FIGURE 2 as a part of a base station (BS, gNB) or FIGURE 3 as a UE.

[0058] As shown in FIGURE 3, the UE 116 includes an antenna 305, a radio frequency (RF) transceiver 310, TX processing circuitry 315, a microphone 320, and receive (RX) processing circuitry 325. The UE 116 also includes a speaker 330, aprocessor 340, an input / output (I / O) interface (IF) 345, atouchscreen 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) 361 and one or more applications 362.

[0059] The RF transceiver 310 receives, from the antenna 305, an incoming RF signal transmitted by a gNB of the network 100. The RF transceiver 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is sent to the RX processing circuitry 325, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal and / or decompressing or correlating. The RX processing circuitry 325 transmits the processed baseband signal to the speaker 330 (such as for voice data) or to the processor 340 for further processing (such as for web browsing data).

[0060] The TX processing circuitry 315 receives analog or digital voice data from the microphone 320 or other outgoing baseband data (such as web data, e-mail, 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 up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna 305.

[0061] The processor 340 can include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 in order to control the overall operation of the UE 116. For example, the processor 340 could 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.

[0062] The processor 340 is also capable of executing other processes and programs resident in the memory 360, such as processes for a bandpass sampled software -defined radio in next generation radar systems. The processor 340 can move data into or out of the memory 360 as required by an executing process. In some embodiments, the processor 340 is configured to execute the applications 362 based on the OS 361 or in response to signals received from gNBs or an operator. The processor 340 is also coupled to the 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 theseaccessories and the processor 340.

[0063] The processor 340 is also coupled to the touchscreen 350 and the display 355. The operator of the UE 116 can use the touchscreen 350 to enter data into the UE 116. The display 355 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and / or at least limited graphics, such as from web sites.

[0064] The memory 360 is coupled to the processor 340. Part of the memory 360 could include a randomaccess memory (RAM), and another part of the memory 360 could include a Flash memory or other readonly memory (ROM).

[0065] Although FIGURE 3 illustrates one example of UE 116, various changes may be made to FIGURE 3. For example, various components in FIGURE 3 could be combined, further subdivided, or omitted and additional components could be added according to particular needs. As a particular example, the processor 340 could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Also, while FIGURE 3 illustrates the UE 116 configured as a mobile telephone or smartphone, UEs could be configured to operate as other types of mobile or stationary devices. As illustrated in FIGURE 3, a radar system provided in the present disclosure can be implemented as a component of the UE 116 or a stand-alone system on behalf of the UE 116. FIGURE 3 does not limit the implementation technologies of the radar system provided in the present disclosure. FIGURE 3 does not limit the implementation technologies of the radar system provided in the present disclosure.

[0066] There are N vehicles in “close” proximity to each other. Each vehicle has an imaging radar. Each vehicle also has other radar systems that operate from different angles and locations on the car. Today, each imaging radar operates in an autonomous fashion and does not require information from the radars of the other vehicles.

[0067] If following issue can be solved, the accuracy and resolution of the combined system of N vehicles can be enhanced.

[0068] In one example, it may be assumed that there are N radars R1 . . . RN. Each radar produces a raw signal SI ... SN that is effectively the result of taking the ADC output of each of receivers and performing a receiver processing to extract information. Each signal SI may be composed of M sub-signals where M is the number of receivers for the radar system. So SI is really a set of data {SI}. Each radar system may also generate a processed signal where a mathematical operation is performed on the set {SI} in order to derive a point cloud {PCI}. {PCI} includes data such as angular information in the azimuth and elevation and range and Doppler shift (corresponding to velocity). Therefore, there are a 4-dimensional representation for each voxel. Therefore, each radar system generates a set of data consisting of {Sm}, {PCm} for radar Rm. This data is also generated in real time, so with each data set, there is an associated time {tm, k} where m is the radar number and k starts from 1 as the first sample and increases over time. Because the radar systems are not synchronized, the time series {tm, k} may not be identical to the time series from radar 1 {tl, k}.

[0069] To first order, it may say that the difference in these “sampling points in time” has an upper bound.It may call this t-delta-max. For example, if all radar systems are creating a repeating signal on their transmitters and the max period of this repetition is t-period-max, then it can say that t-delta-max is < t- period-max. The combined radar system therefore has a timing uncertainty of t-delta-max, i.e., it is not synchronized. It can be said that this lack of synchronization is equivalent to timing jitter for the combined system. The lower the timing jitter, the more “accurate” a picture it may be reconstructed.

[0070] The other variable is that the different vehicles are physically separate from one another. This has the advantage of creating a larger “synthetic” aperture but has the disadvantage that in order to make good use of this, it may need to know the locations of the various TX elements on each vehicle. The reconstruction of a more accurate combined signal processing from N radars requires us to know the location of each Tx. Given that the vehicles are moving, this information needs to be updated frequently.

[0071] Therefore, need the data set that represents the location of each vehicle over time. It may be labelled this as {Lk} (which varies with time). Even though it has stated the need for {Lk}, the real need is to know the relative location of each vehicle relative to the others - not the absolute location. It may be assumed that based on the actual location {Lk}, the relative location between pairs of vehicles is calculated- label this as {RL, k, j } where k and j represent different pairs of vehicles. By way of example, if there are 3 vehicles of interest, then it may be interested in the pairs (1, 2), (1 ,3) and (2, 3). It is understood that (2, 1) can be derived from (1, 2) etc. The data set {RL, k, j} in the simplest form consists of 3 dimensions of azimuth, elevation and range. In one example, a more complete representation may have the element of velocity in it as well, so it can be up to 4 dimensions.

[0072] Assume that each vehicle also has a GPS system (as most modem vehicles and cellphones do). The GPS signal is very valuable in that the GPS signal includes the following information: in addition to longitude, latitude, and altitude, the global positioning system (GPS) provides a critical fourth dimension - time. Each GPS satellite contains multiple atomic clocks that contribute very precise time data to the GPS signals.

[0073] With the availability of the GPS signal, each vehicle is now able to determine an actual location {Lk} of the vehicle. Also, given that the GPS also has a header that provides the time from the GPS atomic clock. To provide the current date, the global positioning system (GPS) keeps an internal count of the number of weeks since January 5, 1980. The government distributes UTC as maintained by the U.S. naval observatory (USNO) via the GPS signal in space with a time transfer accuracy relative to UTC (USNO) of <30 nanoseconds (billionths of a second), 95% of the time. The attached link discusses time dilation - as it relates to relativistic effects. Our concern is not so much the absolute accuracy of time, but to get adjacent vehicles to “read” the same time. GPS-Wiki. In one example, an update Rate is provided. The update rate of a GPS module is how often it calculates and reports the position. The standard for most devices is 1Hz (once per second). UAVs and other fast vehicles may require increased update rates.

[0074] Given that the update rate from the GPS system is once per second, then several “correction factors” need to be considered when computing {Lk} and the time-keeping mechanism within the radar / automobile.

[0075] GPS systems within automobiles have inertial motion units (IMUs) that keep track of accelerationthrough an accelerometer and rotation through a gyro. In addition, they have magnetometers.

[0076] For vehicles that receive their location signal from the GPS system, they can “simultaneously” compute their real location at the time the signal is sent. During the course of a second until the next GPS signal is received a vehicle also needs to update the location based on the speed of the vehicle (determining if it has accelerated and in which direction) and determining if it has “rotated” and in which direction. This computation is necessary to “fill in” the projected location after the GPS signal has been received. It is well understood that such a computation can be done.

[0077] If a vehicle is to transmit the location to the adjacent vehicles, then the vehicle needs to transmit the “extrapolated location.” It may be labelled as {ELk} . From {ELk} the relative locations {ERLk, j } may be derived- these are the counterparts to {Lk} and {RLk} mentioned before.

[0078] It may have thus far defined a mechanism for determining the locations of the vehicles relative to each other. Note that the GPS system is located differently in different vehicles. Therefore, there is a need to define a relative location between the GPS unit and the actual radar RX antennas. This correction term may be vehicle dependent. It may be labelled this as {RL-GPS-RXk} where the generic term RL-GPS-RX is instantiated for vehicle k. This is a fixed number and can be kept in memory. It is therefore desired for the vehicles not to transmit their GPS determined locations, but to provide a correction for the distance between the GPS unit and the RX of the radar.

[0079] The other factor provided in the present disclosure needs to synchronize the radars. Given that the GPS signal is transmitted with a time stamp once a second, there are multiple ways to achieve this synchronization. Each radar system can contain a real time clock (RTC). Once the radar system receives the GPS signal, it “adjusts” it is time to correspond to the time stamp received from the GPS. The assumption is that the amount of correction required to the RTC between GPS signals is minimal. In other words, there is not sufficient drift in the internal oscillator of the RTC during a one second “dead” time.

[0080] In one embodiment, it may be assumed that optionally, the radar system’s high speed clock is synchronized to the GPS signal once per second. This can be done through the RTC or directly via the GPS signal. In such embodiment, it does not require that the high speed clock for the radar system needs to be “completely locked” to the GPS signal. It may be an opportunity to restart the high frequency clock at the same time, but allow the clock to run at the natural frequency { fh } where f is the natural oscillator frequency for vehicle n. In this mode of operation, one can envision a situation where the GPS signal arrives at an inopportune time - where the last TX, RX needs to be discarded in order to resynch with the GPS.

[0081] In one embodiment, the embodiment illustrated in the present disclosure may be unconventional and may cause complications when the radar TX / RX is interrupted. Embodiment illustrated in the present disclosure accomplishes that it allows a form of synchronization of the TX / RX across the N vehicles so that the synthetic aperture radar can benefit from such a synchronization. The downside is that if all of the vehicles adopt this method, then they may all be blasting almost simultaneously which increases the number of interferers.

[0082] In embodiments provided in the present disclosure, instead of synchronizing all of the radarstogether, the time stamp associated with each TX / RX is well calibrated. This means that for the time series {tm}, {tk} referred to in the earlier part of this memo, the value of tm and tk is adjusted through a periodic (once per second) signal from the GPS.

[0083] There is conceivably an adjustment that is needed to {tm} based on the location of each vehicle. Each vehicle may include the different time stamp based on the location of the vehicle because the signals transmitted from the vehicle that is located on geometrically different location includes different time stamp. Such different time stamp included in the different signals may be adjusted using the time delay measurement or compensation of the delay. If the vehicles are located 10 meters apart, then the transit time difference of the GPS signal between the two vehicles may be on the order of lOm / c where c is the speed of light and is approximated as 33nsec. This time delta (time of arrival of the GPS signal) can also be transmitted as part of the communication packet between the vehicles. It may be labelled this additional correction as Delta-time-GPS-vehicle {DTGVm}.

[0084] Followings TABLE 1 shows the acronyms for the terminologies provided in the present disclosure.TABLE 1. Acronyms

[0085] In one embodiment, communications packets for radar on vehicle 1 is provided. In such embodiment, packet- 1: {Other info - will be introduced later}, {SI}, {PCI}, {tl, k}, {LI}, {ELK1}, {RL- GPS-RX 1}, {DTGV 1}. Internal computations from the above: {ERLl,j}, {RL-GPS-RX 1}.

[0086] In one embodiment, identifying a group of vehicles that may cooperate is provide. There are multiple ways to identify the vehicle group: (1) proximity to each other via GPS locations (determination at a vehicle level or an edge device such as a base-station. It may be labelled this clustering mechanism as vehicle-level clustering mechanism (CM-V) for vehicle level decision making and edge-level clustering mechanism (CM-E) as edge level decision making. Proximity to each other via receive signal strength (RSS, determination at a vehicle level). It is labelled this clustering mechanism as CM-RSS. Proximity to each other via an edge device (e.g., a base station) that has received GPS locations and can select the various groupings. This has been previously described and labeled as CM-E.

[0087] Assume one of the above embodiments, The following attributes can be derived: (1) a vehicle can belong to multiple clusters. This can be visualized in the following way: (i) if there is traffic on the road, multiple clusters that have slight overlap with one another may be provided and (ii) a vehicle can belong to multiple clusters. For example, it can belong to one cluster when it is “ahead” of some vehicles and it can belong to another cluster when it is “behind” other vehicles; (2) it may be assumed that the number of clusters that any vehicle can belong to is limited; (3) each vehicle may be assigned an ID number. This ID can be pseudo random number that is generated on the fly or the ID can be a fixed ID that is always associated with the vehicle or some combination thereof. With fixed IDs there is a security and privacy danger; and (4) terminology: (i) vehicle m has an ID. It may be labelled this as IDm: (i) vehicle m belongs to a number of clusters. It may be labelled this as C (m, k) where m is the vehicle and k is the number of clusters. Equivalently, the cluster can be labeled as C (IDm, k) where k={ 1 to Cmax} - where Cmax is the upper limit of the number of clusters a vehicle can belong to.

[0088] In one embodiment, it may be assumed that a vehicle broadcasts the ID and GPS location. In the case where the vehicles may make a decision, each vehicle may look at the GPS location it has received from other vehicles. Vehicle n can select a set of IDm that are in close proximity to a vehicle’s own GPS location. The initial look may be to see which vehicle is in a fixed radius of vehicle n. Further examination of this group of vehicles may yield a subset that is better suited for being part of a cluster to improve the synthetic aperture radar performance. Vehicle n may then invite specific IDm vehicles form a cluster. The clusters may be identified as follows: (1) C-ID-{ID1, ID2, ... IDk} . This nomenclature names the cluster with the member’s IDs; (2) C-ID-{IDa, IDb, ... IDj}; and (3) there can be overlap between the various C- ID-{ . . . } members, similar to a Venn diagram.

[0089] Therefore, each car in the set 1-m transmits the packets (as provided above): (1) packet-1, packet- 2, . . . packet-m. The packets may also have the specific ID of the vehicle > The definition of a packet is thus modified to be the following: (i) packet-1: ID-1, {SI}, {PCI}, {tl,k}, {LI}, {ELK1}, {RL-GPS-RX1 } , {DTGV 1 } ; (2) Embedded within each packet is a GPS location and a time stamp; (3) the GPS location can be processed using the method described in item 2 above; (4) once each vehicle joins a “cluster,” then the cluster ID needs to be appended to the packet. The composition of the packet is thus modified as follows: (i) packet-1: C-ID {set of vehicle IDs in the cluster}, ID-1, {SI}, {PCI}, {tl, k}, {LI}, {ELK1}, {RL- GPS-RX 1 }, {DTGV 1 } and (ii) if the vehicle is part of another cluster, then the vehicle may send another packet- 1 that consists of the new C-ID {containing the set of vehicle IDs in the different cluster} followed by ID-1, {SI}, {PCI}, {tl, k}, {LI}, {ELK1}, {RL-GPS-RX 1}, {DTGV 1}. With this methodology, the vehicles that are part of that specific cluster may see if they are in that cluster and may process the other parameters in the packet. If they are not part of that cluster, then they may ignore the packet.

[0090] Embodiments provided in the present disclosure may: (1) allow the system of vehicles to form clusters and (2) listen to the vehicles in their designated clusters and perform computations. In addition, since the packets also include time stamps, the receiving vehicle may know the following information about the neighbor in the cluster: (1) cluster identifier, (2) ID of the vehicle sending information, (3) raw radar signal from the specific vehicle, (4) point cloud from the specific vehicle, (5) time stamp (not corrected for time of flight), (6) absolute location of the specific vehicle, (7) the extrapolated location of the vehicle between GPS signals, and (8) the time correction factor to account for the location difference between the TX / RX and the GPS receiver, the time of flight correction to be applied to the time-stamp.

[0091] In one embodiment, communications mechanism between vehicles is provided, for example, many V2X standards have been defined for V2V communications, V2x etc.

[0092] In one example, since all of the vehicles in a cluster know the “adjusted” GPS location of each vehicle in that cluster, then packet transmissions between individual vehicles can act as a synchronization signal.

[0093] It may introduce the concept of adjusting the time stamp using a time of flight calculation (based on GPS location separation or extrapolated GPS location separation).

[0094] When a vehicle receives a packet from the neighbors within the cluster, the vehicle can optionally append additional data when the vehicle transmits a new packet. Once a cluster has been formed (it may be assumed that no vehicle belongs to two clusters), then all vehicles within that cluster know each other’s location. In one embodiment, an algorithm is provided to deterministically determines which vehicle in the cluster is the most suitable vehicle to generate the synchronization signal. The algorithm may use a least mean square (LMS) calculation to determine which vehicle has the shortest mean square distance to the others in the cluster. Given a deterministic calculation that may give the same result for all vehicles within a cluster, then the “synchronizing” vehicle is identified. Call this vehicle ID-synch. The synchronization is performed based on a GPS signal, a signal including a time stamp, or a synchronization signal transmitted from a vehicle. A master vehicle (e.g., apparatus) may control the cluster including a plurality of vehicles that is synchronized based on a GPS signal, synchronization signal, or a signal including the time stamp that is adjusted by the master vehicle.

[0095] From here there are two ways to create synchronization as shown in following embodiments.

[0096] In one embodiment, ID-synch knows the time stamps {tm, k} from each vehicle in the cluster and the adjustments that need to be made for time of flight calculations. In such embodiment, ID-synch can send packets that are addressed to individual cars in the packet in the form of: ID-1, t-delay-1, ID-2, t-delay- 2, etc. The term t-delay-m is intended to tell vehicle k that it needs to fire a TX in a fixed time from receiving the packet. The sum of tm, k + t-delay-m is such that this sum is the same for all vehicles. In other words, tl, k+t-delay-l=t2, k+t-delay-2 etc. This notation to delay each vehicle’s firing of the TX such that they all occur simultaneously is one way to synchronize the radars.

[0097] In one embodiment, ID-synch sends out a pulse that initiates a sequence in each radar. Appended to this “initiation signal” is a time value that all radars may “fire.” Each radar calculates the time of flight from ID-synch to each vehicle based on their GPS location. They know the time stamp for ID-synch. They may target their firing (adjusted appropriately) so all of the radars fire at the same time.

[0098] GPS signals may have a finite inaccuracy. It may be relying on the GPS location information to do a lot of our synchronization.

[0099] If the point clouds from each vehicle is considered, it may see some degree of correlation between the point clouds. There may clearly be offsets in the point clouds because not all of the vehicles are at the exact same spot - they are spatially diverse.

[0100] An algorithm can be devised that learns the amount of correction that needs to be applied to a GPS location to make the point clouds consistent with the reported GPS location. This can serve as a first order correction to the reported GPS location. This is equivalent to optical focusing.

[0101] GPS signals may have a finite inaccuracy. It may be relying on the GPS location information to do a lot of our synchronization.

[0102] It may not need the absolute location of each vehicle but need the relative position of each with high accuracy. Instead of relying on the GPS signal which has some inaccuracy, a method where each vehicle sends a packet to one vehicle in the vehicle’s cluster can be devised. The packet may address a specific vehicle. It may say that vehicle 1 sends a packet to vehicle 2. Vehicle 2 may respond with own packet - addressed vehicle 1. This packet may also contain information about how long it took vehicle 2 to process and respond to the signal from vehicle 1. This round-trip time minus the processing time described in item c) above may be a good equivalent to the distance between two vehicles (t / 2c). If all the vehicles in the cluster do the same roundtrip measurement, then the vehicle may have the radius from each vehicle to the other vehicle in the cluster. When there are 4 vehicles, each vehicle may know the distance: (1) d (1, 2), d (1, 3), d (1, 4), (2) d (2, 3), d (2, 4), and (3) d (3, 4).

[0103] From the perspective of ID-Synch which has been selected using a least mean square (LMS) algorithm, it now has 6 parameters to describe the locations of 3 other cars in the cluster. This information is sufficient to reconstruct an accurate relative location between the vehicles.

[0104] A vehicle illustrated in the present disclosure can belong to one or more clusters. (1) clearly, this is a generalization that can create more complexity in the implementation of the algorithms described above, (2) a restatement of the problem is “how does it optimally group a collection of vehicles into multipleclusters such that no vehicle belongs to more than one cluster?” (3) in order to do a good job of optimization, one can use the brute force method of knowing the locations of all vehicles on the road within the reach of a base-station. The base station or other edge device can come up with an optimal “clustering” and can send this optimal clustering to all of the vehicles, and (4) alternatively, if such a decision is made based on a much more limited set of data, then it can end up with a sub-optimal result - which may be okay. In this sub-optimal method, one of many algorithms may be provided as shown in examples below.

[0105] In one example, each vehicle does a tally of how many GPS signals are within a radius from it. Call this vicinity-ID-m where the vehicle has ID-m as the ID.

[0106] In one example, each vehicle broadcasts the vehicle’s ID, GPS location, the number of vehicles within the fixed radius and the vehicle within this radius that has the least mean square distance from others within this radius.

[0107] In one example, for M vehicles, M different reports are provided.

[0108] In one example, a list of descending values of Vicinity-ID-...is provided.

[0109] In one example, vehicles may be grouped into different clusters such that the size of the cluster is maximized.

[0110] In one example, a Venn diagram of different clusters that have overlap with one another is provided, [oni] In one example, the vehicles in the overlap region are assigned to one cluster or another.

[0112] In one example, the decision as to which cluster a vehicle may belong to is an optimization problem where a cost function is minimized. The cost function has to be defined in order to solve this problem, but it is doable.

[0113] In one example, alternatively, one can assign vehicles in the overlap section of the clusters to one cluster or another in a random fashion, an optimal clustering may not be obtained, but this may be good enough.

[0114] In one example, the computation for the clustering may be done on each vehicle in an independent fashion.

[0115] In one example, the first group of vehicles that have formed a cluster may broadcast their cluster ID (comprised of their individual vehicle IDs).

[0116] In one example, this eliminates this group of vehicles from the pool that is available for other clusters. The next group armounces its decision and so on.

[0117] In one example, this re-clustering can be done in one second intervals or some multiple (synchronized to the GPS transmissions).

[0118] In one embodiment, a cooperative transmission and reception for higher resolution imaging are provided.

[0119] In the present disclosure, it has provided that how the vehicles in a cluster may form well known positions (without GPS information) and can be synchronized in time with one another.

[0120] The spatial separation of the vehicles now forms a larger composite antenna for both receive and transmit.

[0121] Since all TX channels and RX channels are now “synchronized,” then this larger aggregation of vehicles / TX / RX channels is considered as a larger aperture system which can in principle create higher resolution radar images.

[0122] For the sake of simplicity, it may be assumed that all radars on the vehicles are the same model. The notion of combining the received signals to form a higher resolution image can be understood more simply.

[0123] If the radars are different models, then the mathematics that is involved for creating a more detailed image will be more complex.

[0124] There are N radar enabled appliances in the home / warehouse etc. In a warehouse or industrial application, there may be robots, the robots are generally referred as appliances. In a home, the appliances can consist of air conditioning units, TVs, vacuum cleaners etc. Some appliances may be stationary. Other appliances may be mobile.

[0125] In the present disclosure, the home / warehouse may be considered as a facility.

[0126] Some appliances may serve as a master (e.g., a master entity, a master apparatus, a master vehicle, a master network entity) . The master coordinates the other appliances. Other appliances may be receiving instructions from the master appliance. It may be referred to these as the slaves (e.g., slave entities, slave apparatus, slave vehicles, slave network entities).

[0127] The slave appliances may have the ability to communicate with one another on a slave-slave basis.

[0128] The slave appliances may have the ability to communicate with the master.

[0129] All appliances including the master may have a unique ID.

[0130] In one example, the master may have an imaging radar that allows it to scan the scene for other appliances and therefore locate a slave “accurately.”

[0131] In one example, the master appliance has the ability to communicate with the other appliances collectively or through an addressing scheme to individual appliances.

[0132] In one example, the master may have an RSS capability.

[0133] In one example, the master may have a capability to measure time of flight for the message the master transmits.

[0134] In one example, the master may also be equipped with a UWB capability.

[0135] In one example, the master may be in a fixed location or the master may be mobile.

[0136] In one example, the master can broadcast a synchronization signal to each appliance. The appliance may respond “immediately” with the unique ID, and a “time-delay” value that represents the time delay between receipt of the signal and transmission of a response. This roundtrip time minus the “time-delay” value represents twice the distance between the master and the appliance.

[0137] In one embodiment, the slaves have the ability to communicate back to the master. There is a slave to slave communication capability. In this communication, each slave addresses another slave (using their address) and a pre-amble that indicates the slave needs a quick response. The addressed slave responds with the ID and a “time-delay” value. Similar to the master-slave communication, the slave to slavecommunication allows each slave to know the distance from another slave. This information is communicated to the master. Once all the slaves have queried each other, the master may know the relative position of each slave. See the mechanism outlined in the vehicle example.

[0138] The slaves can have an RSS capability. The master can “point” in the general direction of the slave and send a signal. The slave may respond with the ID and an RSS value. The master can then alter the angles slightly and probe the space around the slave (receiving the RSS value). The master can then home in on the slave by maximizing the RSS value the master has received. This is an alternative way for the master to know the location of each slave.

[0139] In one example, the master needs to derive the location of each of the slaves - this has been described above.

[0140] In one example, the master needs to be able to address each of the slaves individually or collectively.

[0141] In one example, the master can send commands to each slave.

[0142] In one example, the master can query each slave about the status of the master. The “status” may be a health status for the slave or radar imaging related information from the slave.

[0143] In one example of synchronization, the master may issue a “synchronization” signal. Given that the master knows the relative location of each slave using the data the master has gathered, the master may also know the time the master takes for a signal to reach a slave. As in the case of the vehicle example above, the master can issue a command to “fire” by telling each slave how long after the receipt of the “synchronize” signal each slave needs to fire.

[0144] Embodiment provided in the present disclosure works well for cases where there is a line of sight between the master and the slave. In such embodiment, there may be cases where there is no direct line of sight. This may result in a situation where the master may receive inconsistent information.

[0145] In one example, it may be assumed that slave 1 - SI is behind an object and does not have a direct line of sight.

[0146] In one example, it may be assumed that the other slaves S2-Sn have a direct line of sight with S 1.

[0147] In one example, S2-Sn may report a distance from SI back to the master.

[0148] In one example, S 1 also sends a roundtrip signal to the master (so the master may see a longer path) from S 1. The data from S2-Sn may imply a shorter distance because they have line of sight communications with S 1. This inconsistency may generate an “incorrect” map within the master.

[0149] In one example, the synchronization command from the master may still work properly because the command is relying on the indirect path for the signaling from S 1. The master may give S 1 the longer delay associated with the indirect path timing. In such example, the above shows that the synchronization function may not be compromised but the “mapping” function may be compromised.

[0150] In one embodiment, when the master detects that there is an inconsistency in the reported location of a slave, the master can take additional steps.

[0151] In one example, since the master has the ability to scan the space using an antenna, the master canquery each slave about the RSS value. It can search for a transmit direction that maximizes the RSS value that is returned from the slave. This may identify the shortest path for sending a Tx signal. In some cases, this may not be representative of the shortest path in case the Tx is pointing at a highly reflective surface as opposed to a highly absorbent surface. In any case, the master now has the ability to decide in which direction the Tx may be transmitting.

[0152] In one example, as before there is a time-delay for the slave to respond. There may also be a timedelay for the master to switch to a more optimal transmit direction. These time delays may be taken into account by the master when the master issues the “synchronize” signal. It may use the maximum time necessary into the future in order to issue the “fire” signal.

[0153] In one embodiment, the master knows the time of flight for each slave even if the master is not in the direct line of sight and using this information, the master can issue a “fire” command so that all radars are synchronized.

[0154] FIGURE 4 illustrates an example of functional blocks per vehicle 400 according to various embodiments of the present disclosure. FIGURE 4 does not limit the implementation technologies of the radar system provided in the present disclosure.

[0155] FIGURE 5 illustrates an example of cluster for a radar system 500 according to various embodiments of the present disclosure. FIGURE 5 does not limit the implementation technologies of the radar system provided in the present disclosure.

[0156] FIGURE 6 illustrates another example of cluster for a radar system 600 according to embodiments of the present disclosure. FIGURE 6 does not limit the implementation technologies of the radar system provided in the present disclosure.

[0157] FIGURE 7 illustrates an example of cluster processing 700 according to various embodiments of the present disclosure. FIGURE 7 does not limit the implementation technologies of the radar system provided in the present disclosure.

[0158] FIGURE 8 illustrates an example of time synchronization 800 according to various embodiments of the present disclosure. FIGURE 8 does not limit the implementation technologies of the radar system provided in the present disclosure.

[0159] FIGURE 9 illustrates an example transmitter architecture for sub-channel coded OFDM system 900 according to various embodiments of the present disclosure. FIGURE 9 does not limit the implementation technologies of the radar system provided in the present disclosure.

[0160] As illustrated in FIGURE 9, a transmitter 900 may be implemented with a sequence block 902, an IFFT block 906, a mapper block 908, DAC blocks 910 and 912, a phase shifter block 914, a clock generator block 916, multiplier blocks 918 and 920, an RF processing block 922, and a MAC controller block 924.

[0161] As illustrated in FIGURE 9, the transmitter 900 generates sub-band channel signals modulating carriers f0, . . . , f -i . The sub-band signal is generated sequentially in time. The sequence block 902 generates a sub-band CAZAC sequence by DFT pre-coding of a Zadoff-Chu sequence. The IFFT block 906 takes the parallel pre-coded CAZAC sequence and converts the parallel stream of pre-coded CAZAC sequence totime-domain signal. The mapper block 908 converts the time domain signal to serial stream and adds cyclic- prefix. Optional guard time is added. The DAC blocks 910 and 912 take the in-phase and quadrature components of the mapper block 908 and converts them to analog data in-phase and quadrature signal. The phase shifter block 914 generates the quadrature analog signals of carrier frequency of the clock generator block 916. The multiplier blocks of 918 and 920 are modulated signal by the carrier frequency. In RF processing block 922, the modulated carrier is further processed by shaping filter, and amplified and send to the antenna. The MAC controller block 924 configures and assigns time -frequency and code resources of the transmitter.

[0162] The embodiment of the transmitter architecture for sub-channel coded OFDM system 900 illustrated in FIGURE 9 is for illustration only. FIGURE 9 does not limit the scope of this disclosure to any particular implementation.

[0163] In one embodiment, the transmitter architecture for sub-channel coded OFDM system 900 may be implemented at a base station (e.g., 101-103 as illustrated in FIGURE 1) ora UE (e.g., 111-116 as illustrated in FIGURE 1).

[0164] In a multi-channel coded OFDM system, multiple instances of transmit chain are implemented and processed in parallel. In a sub-channel coded OFDM system, a coded sub-band OFDM signal is modulated with a carrier frequency corresponding to a sub-channel for each slot.

[0165] FIGURE 10 illustrates an example transmitter architecture for multi-channel coded OFDM system 1000 according to various embodiments of the present disclosure. The embodiment of the transmitter architecture for multi-channel coded OFDM system 1000 illustrated in FIGURE 10 is for illustration only. FIGURE 10 does not limit the scope of this disclosure to any particular implementation.

[0166] As illustrated in FIGURE 10, the transmitter for multi-channel coded OFDM radar system 1000 may include at least one transmitter (e.g., 1030, 1040, and 1050). The transmitter 1030 may be implemented with a sequence block 1002, an inverse fast Fourier transform (IFFT) block 1006, a mapper block 1008, digital to analog converters (DACs) blocks 1010 and 1012, a phase shifter block 1014, a clock generator block 1016, multiplier blocks 1018 and 1020, an RF processing block 1022, and a MAC controller block 1024. The transmitter 1040 and 1050 may include the same elements of the transmitter 1030, respectively. The transmitters 1040 and 1050 may be duplicated to implement the RADAR system.

[0167] In one embodiment, the transmitter architecture for multi-channel coded OFDM system 1000 may be implemented at a base station (e.g., 101-103 as illustrated in FIGURE 1) or a UE (e.g., 111-116 as illustrated in FIGURE 1).

[0168] As illustrated in FIGURE 10, the transmitter 1000 (e.g., for multi-channel coded OFDM system) generates a transmit signal composed of multiple sub-band channels modulating carriers f0, ... , f -i. The sequence block 1002 generates a sub-band CAZAC sequence by DFT pre-coding of a Zadoff-Chu sequence. The IFFT block 1006 takes the parallel pre-coded CAZAC sequence and converts the parallel stream of pre-coded CAZAC sequence to time-domain signal. The mapper block 1008 converts the time domain signal to serial stream and adds cyclic-prefix. Optional guard time is added. The DAC blocks 1010 and1012 take the in-phase and quadrature components of the output of the mapper block 1008 and converts them to analog data in-phase and quadrature signal. The phase shifter block 1014 generates the quadrature phase carrier frequency. In-phase and quadrature analog signals of the outputs of the DAC blocks 1010 and 1012, are modulated by the carrier frequency and quadrature carrier frequency in the multiplier blocks 1018 and 1020. In the RF processing block 1022, the modulated signal is further processed by a shaping fdter and amplified and send to the antenna. The MAC controller block 1024 configures and assigns timefrequency and code resources of the transmitter.

[0169] As illustrated in FIGURE 10 of the transmitter, the analog circuit receives the output of the DAC, modulates the carrier, amplifies and filters the signal and feeds the signal to the antenna. As illustrated in FIGURE 11 of the receiver, the analog circuit receives the signal from the antenna, filters and amplifies the signal, demodulates the carrier to baseband and sends the carrier to ADC. The DAC converts the digital baseband signal to analog signal. The analog circuit may implement analog beamforming for multiple antennas by combining power amplifier (PA), filters and phase shifters. The ADC converts the analog signal to digital signal. The digital circuit in the transmitter generates digital waveform by baseband processing algorithm from sequences and symbol modulation and multiplexing. The digital circuit in the receiver processes the baseband signal and generates output signal such as decision statistic.

[0170] FIGURE 11 illustrates an example receiver architecture for multi-channel coded OFDM radar system 1100 in accordance with various embodiments of the present disclosure. The embodiment of the receiver architecture for multi-channel coded OFDM radar system 1100 illustrated in FIGURE 11 is for illustration only. FIGURE 11 does not limit the scope of this disclosure to any particular implementation.

[0171] As illustrated in FIGURE 11, the receiver for multi-channel coded OFDM radar system 1100 may include at least one receiver (e.g., 1130, 1140, and 1150). The receiver 1130 may be implemented with an RF processing block 1102, a phase shifter block 1104, multiplier blocks 1106 and 1108, ADC blocks 1110 and 1112, a demapper block 1114, an IFFT block 1116, a baseband processing block 1118, a combiner block 1120, a clock generator block 1124, and a range-doppler processing block 1122. The receiver 1140 and 1150 may include the same elements of the receiver 1130, respectively. The receiver 1140 and 1150 may be duplicated to implement the RADAR system.

[0172] In one embodiment, the receiver architecture for multi-channel coded OFDM radar system 1100 may be implemented at a base station (e.g., 101-103 as illustrated in FIGURE 1) or a UE (e.g., 111-116 as illustrated in FIGURE 1).

[0173] A receiver architecture for a sub-band coded OFDM system is shown in FIGURE 11. For each subband, a signal is demodulated followed by a sub-band ADC. After CP removal, a correlation is computed in a frequency domain, by taking a fast Fourier transform (FFT) of a baseband signal, multiplication with the complex conjugate of the reference signal, followed by an inverse fast Fourier transform (IFFT).

[0174] A correlation value is interpolated by up-sampling followed by a low pass filet (LPF). Each processed sub-band signal is added. Detection statistic is formed by taking the amplitude or amplitude square, followed by a constant false alarm rate (CFAR) detector. A post-processing is achieved to removethe artefacts. Also, the correlation output is stored in a memory for Doppler estimation.

[0175] In a multi-channel coded OFDM system, multiple instances of a receiver chain are implemented and processed in parallel. In a sub-channel coded OFDM system, each sub-channel output is accumulated overtime for detection and post-processing.

[0176] In the blocks 1102 to 1118 describes sub-band signal processing. In the RF processing block 1102, a quadrature carrier frequency is generated. In the multiplier blocks 1106 and 1108, received signal from the antenna is demodulated to generate in-phase and quadrature components of the analog signal. In the ADC blocks 1110 and 1112, the analog signal is converted to digital signal by ADC. In the demapper block 1114, received I / Q signals are converted to parallel stream by serial-to-parallel (S / P) converter, and cyclic- prefix is removed. In the FFT block 1116, the output of the demapper block 1114 is further converted to frequency domain signal by FFT. In the baseband processing block 1118, the output signal of the FFT block 1116 is multiplied by complex conjugate of the stored reference signal. In the baseband processing block 1118, the output of complex multiplier is converted to time-domain signal by IFFT. The signal is up- sampled and filtered in the baseband processing block 1118.

[0177] In the combiner block 1120, the combiner aggregates signals from the receiver 1130, 1140, and 1150 to generate wideband correlation output.

[0178] The range-Doppler processing block 1122 takes amplitude or amplitude square. The range-Doppler processing block 1122 applies a threshold according to CFAR criterion for detection of the result.

[0179] The range-Doppler processing block 1122 stores the combiner output in memory over multiple symbols. The range-Doppler processing block 1122 processes stored symbols and estimates Doppler.

[0180] In the range-Doppler processing block 1122, the detected result and Doppler processed signal is further processed in post processing.

[0181] A waveform for each sub-channel can be a filter-bank multi-carrier (FBMC) or a single -carrier (SC) without changing the overall architecture of the system. A sub-band OFDM signal can be a cyclic- prefix free signal.

[0182] A radar system can be built as a 3D radar for range, angle-of-arrival, and Doppler estimation or 4D imaging radar for Azimuth, elevation, range and Doppler images.

[0183] FIGURE 12 illustrates a flowchart of method 1200 for a coordinated radar system according to various embodiments of the present disclosure, as may be performed by an apparatus or at least one apparatus (e.g., 111-116 and / or 101-103 as illustrated in FIGURE 1). The embodiment of the method 1200 illustrated in FIGURE 12 is for illustration only. One or more of the components illustrated in FIGURE 12 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions. FIGURE 12 does not limit the scope of this disclosure to any particular implementation.

[0184] As illustrated in FIGURE 12, the method 1200 begins at step 1202. In step 1202, an apparatus receives, from at least one apparatus including a second apparatus, signals.

[0185] In step 1204, the apparatus identifies a time stamp embedded in each signal of the signals receivedfrom the at least one apparatus.

[0186] In step 1206, the apparatus identifies a location of each apparatus of the at least one apparatus.

[0187] In step 1208, the apparatus adjusts, based on the location of each apparatus, the time stamp of each apparatus.

[0188] In step 1210, the apparatus transmits, to the at least one apparatus, a signal including the adjusted time stamp.

[0189] In one embodiment, the apparatus transmits, to the at least one apparatus, a synchronization signal and an ID of the first apparatus for determining a cluster including a group of apparatus from the at least one apparatus, the group of apparatus including the second apparatus; and receive, from the at least one apparatus, synchronization signals.

[0190] In one embodiment, the apparatus identifies, based on the synchronization signals, proximity information between the first apparatus and each of the at least one apparatus, identifies, based on the proximity information, the group of apparatus, identifies the cluster including the group of apparatus, and synchronizes with each of the group of apparatus based on the proximity information.

[0191] In one embodiment, the apparatus identifies, based on information received from a GPS, the group of apparatus for determining the cluster.

[0192] In one embodiment, the apparatus, identifies, based on IDs of the group of apparatus, the group of apparatus for determining the cluster and identifies, based on a selection operation, a master apparatus from the group of apparatus.

[0193] In one embodiment, the apparatus identifies, based on embedded IDs of the group of apparatus and a location of a GPS of the group of apparatus, the group of apparatus for determining the cluster.

[0194] In one embodiment, the apparatus transmits the signal including a data payload that comprise at least one of global positioning system location separation information or extrapolated location separation information; and the signal including the data payload is broadcast to a cluster including a group of apparatus that comprises the second apparatus.

[0195] In one embodiment, the apparatus receives, from the at least one apparatus, signals for performing a synchronization operation with the at least one apparatus and applies a time offset to the signals in order to transmit, to the at least one apparatus, a response signal in a pre-defined time.

[0196] In one embodiment, the apparatus performs at least one of a cooperative transmission or a cooperative reception with each of a group of apparatus and performs a spatial diversity operation based on each of the signals.

[0197] In one embodiment, the apparatus receives, from the at least one apparatus, distance information and a roundup (e.g., roundtrip) signal, wherein the first apparatus includes invisible line of sight with the at least one apparatus and transmits, to the at least one apparatus, a synchronization command based on the distance information and the roundup (e.g., roundtrip) signal associated with an indirect path timing to synchronize with the at least one apparatus.

[0198] In such embodiments, the first apparatus is a vehicle including a radarthat comprises the transmitterand the receiver, the at least one apparatus is at least one vehicle including the radar that comprises the transmitter and the receiver, a group of apparatus is a group of vehicles including the radar that comprises the transmitter and the receiver, and the second apparatus included in the group of apparatus is a vehicle including the radar that comprises the transmitter and the receiver.

[0199] The description in the present application should not be read as implying that any particular element, step, or function is an essential or critical element that must be included in the claim scope. The scope of patented subject matter is defined only by the allowed claims. Moreover, none of the claims is intended to invoke 35 U.S.C. § 112(f) with respect to any of the appended claims or claim elements unless the exact words “means for” or “step for” are explicitly used in the particular claim, followed by a participle phrase identifying a function. Use of terms such as (but not limited to) “mechanism,” “module,” “device,” “unit,” “component,” “element,” “member,” “apparatus,” “machine,” “system,” “processor,” or “controller” within a claim is understood and intended to refer to structures known to those skilled in the relevant art, as further modified or enhanced by the features of the claims themselves, and is not intended to invoke 35 U.S.C. § 112(f).

[0200] While this disclosure has described certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the scope of this disclosure, as defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A first apparatus comprising: a transmitter; a receiver operably coupled to the transmitter, the receiver configured to receive, from at least one apparatus including a second apparatus, signals; and at least one processor operably coupled to the transmitter and the receiver, the at least one processor configured to: identify a time stamp embedded in each signal of the signals received from the at least one apparatus, identify a location of each apparatus of the at least one apparatus, and adjust, based on the location of each apparatus, the time stamp of each apparatus, wherein the transmitter is configured to transmit, to the at least one apparatus, a signal including the adjusted time stamp.

2. The first apparatus of Claim 1, wherein the transmitter is further configured to: transmit, to the at least one apparatus, a synchronization signal and an identification (ID) of the first apparatus for determining a cluster including a group of apparatus from the at least one apparatus, the group of apparatus including the second apparatus; and receive, from the at least one apparatus, synchronization signals.

3. The first apparatus of Claim 2, wherein the at least one processor is further configured to: identify, based on the synchronization signals, proximity information between the first apparatus and each of the at least one apparatus; identify, based on the proximity information, the group of apparatus; identify the cluster including the group of apparatus; and synchronize with each of the group of apparatus based on the proximity information.

4. The first apparatus of Claim 2, wherein the at least one processor is further configured to identify, based on information received from a global positioning system (GPS), the group of apparatus for determining the cluster.

5. The first apparatus of Claim 2, wherein the at least one processor is further configured to: identify, based on IDs of the group of apparatus, the group of apparatus for determining the cluster; and identify, based on a selection operation, a master apparatus from the group of apparatus.

6. The first apparatus of Claim 2, wherein the at least one processor is further configured to identify, based on embedded IDs of the group of apparatus and a location of a global positioning system (GPS) of the group of apparatus, the group of apparatus for determining the cluster.

7. The first apparatus of Claim 1, wherein: the transmitter is further configured to transmit the signal including a data payload that comprise at least one of global positioning system location separation information or extrapolated location separation information; and the signal including the data payload is broadcast to a cluster including a group of apparatus that comprises the second apparatus.

8. The first apparatus of Claim 1 , wherein: the receiver is further configured to receive, from the at least one apparatus, signals for performing a synchronization operation with the at least one apparatus; and the at least one processor is further configured to apply a time offset to the signals in order to transmit, to the at least one apparatus, a response signal in a pre-defined time.

9. The first apparatus of Claim 1, wherein: the first apparatus is a vehicle including a radar that comprises the transmitter and the receiver; the at least one apparatus is at least one vehicle including the radar that comprises the transmitter and the receiver; a group of apparatus is a group of vehicles including the radar that comprises the transmitter and the receiver; and the second apparatus included in the group of apparatus is a vehicle including the radar that comprises the transmitter and the receiver.

10. The first apparatus of Claim 1, wherein the at least one processor is further configured to: perform at least one of a cooperative transmission or a cooperative reception with each of a group of apparatus; and perform a spatial diversity operation based on each of the signals.

11. The first apparatus of Claim 1, wherein: the receiver is further configured to receive, from the at least one apparatus, distance information and a roundtrip signal, wherein the first apparatus includes invisible line of sight with the at least one apparatus; and the transmitter is further configured to transmit, to the at least one apparatus, a synchronization command based on the distance information and the roundtrip signal associated with an indirect path timingto synchronize with the at least one apparatus.

12. A second apparatus comprising: a receiver; at least one processor operably coupled to the receiver, the at least one processor configured to: generate a time stamp, and embed the time stamp into a signal; and a transmitter operably coupled to the receiver and the at least one processor, the transmitter configured to: transmit, to a first apparatus, the signal including the time stamp, and receive, from the first apparatus, a corresponding signal including an adjusted time stamp, wherein a location of the second apparatus is identified and the adjusted time stamp is identified based on the location of the second apparatus.

13. The second apparatus of Claim 12, wherein the receiver is further configured to: receive, from the first apparatus, a synchronization signal and an identification (ID) of the first apparatus for determining a cluster including a group of apparatus from at least one apparatus, the group of apparatus including the second apparatus; and transmit, to the first apparatus, synchronization signals.

14. The second apparatus of Claim 12, wherein: the receiver is further configured to receive the signal including a data payload that comprise at least one of global positioning system location separation information or extrapolated location separation information; and the signal including the data payload is broadcast to a cluster including a group of apparatus that comprises the second apparatus.

15. The second apparatus of Claim 12, wherein the transmitter is further configured to transmit, to the first apparatus, signals for performing a synchronization operation with the at least one apparatus.

16. The second apparatus of Claim 12, wherein: the first apparatus is a first vehicle including a radar that comprises the transmitter and the receiver; the at least one apparatus is at least one vehicle including the radar that comprises the transmitter and the receiver; a group of apparatus is a group of vehicles including the radar that comprises the transmitter and the receiver; and the second apparatus included in the at least one apparatus is a second vehicle including the radarthat comprises the transmitter and the receiver.

17. The second apparatus of Claim 12, wherein: the transmitter is further configured to transmit, to the first apparatus, distance information and a roundtrip signal, the first apparatus including invisible line of sight with the at least one apparatus; and the receiver is further configured to receive, from the first apparatus, a synchronization command based on the distance information and the roundtrip signal associated with an indirect path timing to synchronize with the first apparatus.

18. A method of a first apparatus, the method comprising: receiving, from at least one apparatus including a second apparatus, signals; identifying a time stamp embedded in each signal of the signals received from the at least one apparatus; identifying a location of each apparatus of the at least one apparatus; adjusting, based on the location of each apparatus, the time stamp of each apparatus; and transmitting, to the at least one apparatus, a signal including the adjusted time stamp.

19. The method of Claim 18, further comprising: transmitting, to the at least one apparatus, a synchronization signal and an identification (ID) of the first apparatus for determining a cluster including a group of apparatus from the at least one apparatus, the group of apparatus including the second apparatus; and receiving, from the at least one apparatus, synchronization signals.

20. The method of Claim 19, further comprising: identifying, based on the synchronization signals, proximity information between the first apparatus and each of the at least one apparatus; identifying, based on the proximity information, a group of apparatus; identifying the cluster including the group of apparatus; and synchronizing with each of the group of apparatus based on the proximity information.

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