Radar Collaboration for Multi-Radar Coexistence

Abstract

Techniques are disclosed for transmitting and receiving multiple encoded information bits on a radar signal. In one aspect, a transmitter radar generates a first set of phase - decoded modulated symbols to convey multiple encoded information bits, generates a second set of phase - decoded modulated symbols as reference symbols with known phase modulation, phase - decodes a plurality of chirps of the radar signal based on the first set of phase - decoded modulated symbols and the second set of phase - decoded modulated symbols, and transmits the plurality of chirps based on the phase - decoding. A receiver radar determines a phase difference between the receiver and the transmitter radar based on the phases of the plurality of chirps, equalizes the phase based on the determined phase difference, determines a phase code of the first set of symbols based on the equalized phase, and decodes the encoded information bits based on the phase code of the first set of symbols.

Description

[0001] Cross - Reference to Related Applications

[0002] This patent application claims the benefit of U.S. Provisional Application No. 62 / 908,356, filed on September 30, 2019, entitled "RADAR COORDINATION FOR MULTI - RADAR COEXISTENCE" and U.S. Non - Provisional Application No. 17 / 037,288, filed on September 29, 2019, entitled "RADAR COORDINATION FOR MULTI - RADAR COEXISTENCE", both of which have been assigned to the assignee of this application and are hereby incorporated by reference in their entirety. Technical Field

[0003] Aspects of the present disclosure generally relate to autonomous or semi - autonomous driving technologies. Background Art

[0004] Modern motor vehicles are increasingly incorporating technologies that help drivers avoid drifting into adjacent lanes or making unsafe lane changes (e.g., lane departure warning (LDW)), or that warn them of other vehicles behind when they are backing up, or that automatically brake if the vehicle in front suddenly stops or decelerates (e.g., forward collision warning (FCW)), etc. The continued development of automotive technologies aims to provide greater safety advantages and ultimately provide an autonomous driving system (ADS) that can handle the entire driving task without user intervention.

[0005] Six levels have been defined to achieve full automation. At level 0, the human driver performs all driving. At level 1, the advanced driver assistance system (ADAS) on the vehicle can sometimes assist the human driver with either steering or braking / acceleration, but not both simultaneously. At level 2, the ADAS on the vehicle can actually control both steering and braking / acceleration simultaneously in some cases. The human driver must always remain fully engaged and perform the remaining driving tasks. At level 3, the ADS on the vehicle can perform all aspects of the driving task in some cases. In those cases, the human driver must be ready to take back control when the ADS requests it. In all other cases, the human driver performs the driving task. At level 4, the ADS on the vehicle can perform all driving tasks and monitor the driving environment, essentially completing all driving in some cases. In those cases, the human does not need to be fully engaged. At level 5, the ADS on the vehicle can perform all driving in all cases. The human occupants are just passengers and do not need to participate in driving. Summary of the Invention

[0006] The following presents a simplified summary of the invention related to one or more aspects disclosed herein. Thus, the following summary of the invention should not be considered a broad review related to all contemplated aspects, nor should the following summary be considered to identify key or critical elements related to all contemplated aspects or to delineate the scope associated with any particular aspect. Accordingly, the sole purpose of the following summary is to present certain concepts related to one or more aspects associated with the mechanisms disclosed herein in a simplified form prior to the detailed description presented below.

[0007] In one aspect, a method of transmitting a plurality of encoded information bits on a radar signal by a transmitter radar includes: generating a first set of phase - decoded symbols modulated by phase - shift keying (PSK) to convey the plurality of encoded information bits; generating a second set of PSK - modulated phase - decoded symbols as reference symbols having a known phase modulation; phase - decoding a plurality of chirps of the radar signal based on the first set of PSK - modulated phase - decoded symbols and the second set of PSK - modulated phase - decoded symbols; and transmitting the plurality of chirps of the radar signal based on the phase - decoding.

[0008] In one aspect, a method of receiving a plurality of encoded information bits on a radar signal by a receiver radar includes: receiving the plurality of chirps of the radar signal from a transmitter radar, wherein the plurality of chirps of the radar signal are phase - decoded based on a first set of PSK - modulated phase - decoded symbols and a second set of PSK - modulated phase - decoded symbols, wherein the first set of PSK - modulated phase - decoded symbols conveys the plurality of encoded information bits, and wherein the second set of PSK - modulated phase - decoded symbols is a reference symbol having a known phase modulation; determining a phase difference between the receiver radar and the transmitter radar based on the phases of the plurality of chirps of the radar signal phase - decoded based on the second set of PSK - modulated phase - decoded symbols; equalizing the phases of the plurality of chirps of the radar signal based on the determined phase difference; determining a phase code of the first set of PSK - modulated phase - decoded symbols based on the equalized phases of the plurality of chirps; and decoding the plurality of encoded information bits based on the phase code of the first set of PSK - modulated phase - decoded symbols.

[0009] In one aspect, an apparatus includes a transmitter radar configured to: generate a first set of PSK - modulated phase - decoded symbols to convey a plurality of encoded information bits; generate a second set of PSK - modulated phase - decoded symbols as reference symbols having a known phase modulation; phase - decode a plurality of chirps of a radar signal based on the first set of PSK - modulated phase - decoded symbols and the second set of PSK - modulated phase - decoded symbols; and transmit the plurality of chirps of the radar signal based on the phase - decoding.

[0010] On the one hand, a device includes a receiving radar configured to: receive a plurality of chirps of a radar signal from a transmitting radar, wherein the plurality of chirps of the radar signal are phase decoded according to a first set of phase decoded symbols modulated by PSK and a second set of phase decoded symbols modulated by PSK, wherein the first set of phase decoded symbols modulated by PSK conveys a plurality of encoded information bits, and wherein the second set of phase decoded symbols modulated by PSK are reference symbols with known phase modulation; determine a phase difference between the receiving radar and the transmitting radar based on the phases of the plurality of chirps of the radar signal phase decoded according to the second set of phase decoded symbols modulated by PSK; equalize the phases of the plurality of chirps of the radar signal based on the determined phase difference; determine a phase code of the first set of phase decoded symbols modulated by PSK based on the equalized phases of the plurality of chirps; and decode the plurality of encoded information bits based on the phase code of the first set of phase decoded symbols modulated by PSK.

[0011] On the one hand, a device includes: means for generating a first set of phase decoded symbols modulated by PSK to convey a plurality of encoded information bits; means for generating a second set of phase decoded symbols modulated by PSK as reference symbols with known phase modulation; means for phase decoding a plurality of chirps of a radar signal according to the first set of phase decoded symbols modulated by PSK and the second set of phase decoded symbols modulated by PSK; and means for transmitting the plurality of chirps of the radar signal according to the phase decoding.

[0012] On the one hand, a device includes: means for receiving a plurality of chirps of a radar signal from a transmitting radar, wherein the plurality of chirps of the radar signal are phase decoded according to a first set of phase decoded symbols modulated by PSK and a second set of phase decoded symbols modulated by PSK, wherein the first set of phase decoded symbols modulated by PSK conveys a plurality of encoded information bits, and wherein the second set of phase decoded symbols modulated by PSK are reference symbols with known phase modulation; means for determining a phase difference between the receiving radar and the transmitting radar based on the phases of the plurality of chirps of the radar signal phase decoded according to the second set of phase decoded symbols modulated by PSK; means for equalizing the phases of the plurality of chirps of the radar signal based on the determined phase difference; means for determining a phase code of the first set of phase decoded symbols modulated by PSK based on the equalized phases of the plurality of chirps; and means for decoding the plurality of encoded information bits based on the phase code of the first set of phase decoded symbols modulated by PSK.

[0013] On the one hand, a non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions including: at least one instruction that instructs a transmitter radar to generate a first set of phase-decoded symbols modulated by PSK to convey a plurality of encoded information bits; at least one instruction that instructs the transmitter radar to generate a second set of phase-decoded symbols modulated by PSK as reference symbols with known phase modulation; at least one instruction that instructs the transmitter radar to perform phase decoding on a plurality of chirps of a radar signal according to the first set of phase-decoded symbols modulated by PSK and the second set of phase-decoded symbols modulated by PSK; and at least one instruction that instructs the transmitter radar to transmit the plurality of chirps of the radar signal according to the phase decoding.

[0014] On the one hand, a non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions including: at least one instruction that instructs a receiver radar to receive a plurality of chirps of a radar signal from a transmitter radar, wherein phase decoding is performed on the plurality of chirps of the radar signal according to a first set of phase-decoded symbols modulated by PSK and a second set of phase-decoded symbols modulated by PSK, wherein the first set of phase-decoded symbols modulated by PSK conveys a plurality of encoded information bits, and wherein the second set of phase-decoded symbols modulated by PSK is a reference symbol with known phase modulation; at least one instruction that instructs the receiver radar to determine a phase difference between the receiver radar and the transmitter radar based on the phases of the plurality of chirps of the radar signal phase-decoded according to the second set of phase-decoded symbols modulated by PSK; at least one instruction that instructs the receiver radar to equalize the phases of the plurality of chirps of the radar signal based on the determined phase difference; at least one instruction that instructs the receiver radar to determine a phase code of the first set of phase-decoded symbols modulated by PSK based on the equalized phases of the plurality of chirps; and at least one instruction that instructs the receiver radar to decode the plurality of encoded information bits based on the phase code of the first set of phase-decoded symbols modulated by PSK.

[0015] Based on the drawings and the detailed description, other objectives and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings are presented to assist in describing various aspects of the present disclosure and are provided only for illustration of the aspects and not for limiting it.

[0017] Figure 1 is a diagram showing an example of a wireless communication system and an access network according to various aspects of the present disclosure.

[0018] Figure 2A and 2BShows an example wireless network structure in accordance with various aspects of the present disclosure.

[0019] Figure 3 Is a top view of a vehicle employing an integrated radar-camera sensor behind a windshield in accordance with various aspects of the present disclosure.

[0020] Figure 4 Shows an in-vehicle computer architecture in accordance with various aspects of the present disclosure.

[0021] Figure 5 Is a schematic diagram of an occupancy radar sensed in accordance with various aspects of the present disclosure.

[0022] Figure 6A Is a diagram showing an example of the present vehicle and two target vehicles in accordance with various aspects of the present disclosure.

[0023] Figure 6B Is a graph showing an example of how much higher the received power of a direct radar signal can be than the received power of a reflected radar signal.

[0024] Figure 7A Is a diagram showing an example of the present vehicle and multiple interfering target vehicles in accordance with various aspects of the present disclosure.

[0025] Figure 7B Is a graph showing an example of false detection probabilities in different ranges.

[0026] Figure 8 Is a graph showing an example of false detection probabilities in different ranges.

[0027] Figure 9A Is a diagram showing an example of a transmitter-side phase-decoded frequency-modulated continuous wave (FMCW) waveform in accordance with various aspects of the present disclosure.

[0028] Figure 9B Is a diagram showing an example of a receiver-side phase-decoded FMCW waveform in accordance with various aspects of the present disclosure.

[0029] Figure 10 and 11 Show exemplary methods in accordance with various aspects of the present disclosure. Detailed Description

[0030] Aspects of the present disclosure are provided in the following description and the associated drawings for various examples provided for illustrative purposes. Alternative aspects can be designed without departing from the scope of the present disclosure. Additionally, well-known elements of the present disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the present disclosure.

[0031] Those skilled in the art should understand that any one of a variety of different technologies and techniques can be used to represent the information and signals described below. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the following description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the specific application, in part on the desired design, in part on the corresponding technology, etc.

[0032] In addition, many aspects are described in accordance with action sequences performed by elements of, for example, a computing device. It will be recognized that the various actions described herein can be performed by specific circuitry (e.g., application specific integrated circuit (ASIC)), by program instructions run by one or more processors, or by a combination of both. Additionally, it can be considered that the action sequences described herein are fully embodied in any form of non-transitory computer-readable storage medium storing a corresponding set of computer instructions, which when run will cause or direct the associated processor of the device to perform the functionality described herein. Thus, the various aspects of the present disclosure can be embodied in many different forms, all of which are considered to be within the scope of the claimed subject matter. Additionally, for each aspect described herein, the corresponding form of any such aspect can be described as, for example, "logic configured to perform the described actions".

[0033] As used herein, unless otherwise specified, the terms "user equipment" (UE) and "base station" do not purport to be specific to or otherwise limited to any particular radio access technology (RAT). In general, a UE can be any wireless communication device used by a user to communicate over a wireless communication network (e.g., a mobile phone, router, tablet computer, laptop computer, tracking device, wearable device (e.g., smart watch, glasses, augmented reality (AR) / virtual reality (VR) headset, etc.), vehicle (e.g., car, motorcycle, bicycle, etc.), Internet of Things (IoT) device, etc.). The UE can be mobile or can be stationary (e.g., at certain times) and can communicate with a radio access network (RAN). As used herein, the term "UE" can be interchangeably referred to as "access terminal" or "AT", "client device", "wireless device", "subscriber equipment", "subscriber terminal", "subscriber station", "user terminal" or "UT", "mobile device", "mobile terminal", "mobile station", or variants thereof. In general, a UE can communicate with a core network via a RAN, and through the core network, the UE can connect to external networks such as the Internet and to other UEs. Of course, for a UE, other mechanisms for connecting to the core network and / or the Internet, such as via a wired access network, a wireless local area network (WLAN) network (e.g., based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, etc.), etc., are also possible.

[0034] A base station can operate according to one of several RATs for communicating with a UE depending on the network in which it is deployed and can alternatively be referred to as an access point (AP), network node, NodeB, evolved NodeB (eNB), next-generation eNB (ng-eNB), new radio (NR) Node B (also referred to as gNB or gNodB), etc. A base station can be mainly used to support wireless access of a UE, including supporting data, voice, and / or signaling connections for the supported UEs. In some systems, a base station can purely provide edge node signaling functions, while in other systems, it can provide additional control and / or network management functions. The communication link through which a UE signals to a base station can be referred to as an uplink (UL) channel (e.g., reverse traffic channel, reverse control channel, access channel, etc.). The communication link through which a base station signals to a UE can be referred to as a downlink (DL) or forward link channel (e.g., paging channel, control channel, broadcast channel, forward traffic channel, etc.). As used herein, the term traffic channel (TCH) can refer to an uplink / reverse or downlink / forward traffic channel.

[0035] The term "base station" can refer to a single physical transmit receive point (TRP) or can refer to multiple physical TRPs that may or may not be co-located. For example, in the case where the term "base station" refers to a single physical TRP, the physical TRP can be an antenna or an antenna array of the base station, which corresponds to a cell (or several cell sectors) of the base station. In the case where the term "base station" refers to multiple co-located physical TRPs, each of the physical TRPs can be an antenna array of the base station (e.g., as in a multiple input multiple output (MIMO) system or in the case where the base station employs beamforming). In the case where the term "base station" refers to multiple non-co-located physical TRPs, the physical TRPs can be a distributed antenna system (DAS) (a network of spatially separated antennas or antenna arrays connected to a common source via a transmission medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, the non-co-located physical TRPs can be a serving base station that receives measurement reports from the UE and neighboring base stations whose reference radio frequency (RF) signals (or simply "reference signals") the UE is measuring. Since the TRP is the point from which the base station transmits and receives wireless signals, as used herein, a reference to transmitting from or receiving at the base station will be understood to refer to a particular TRP of the base station.

[0036] In some embodiments that support UE positioning, the base station may not support wireless access of the UE (e.g., may not support data, voice, and / or signaling connections of the UE), but instead may transmit signals to the UE for the UE to measure and / or may receive and measure signals transmitted by the UE. Such a base station may be referred to as a positioning beacon (e.g., when transmitting signals to the UE) and / or a position measurement unit (e.g., when receiving and measuring signals from the UE).

[0037] An "RF signal" includes an electromagnetic wave of a given frequency that transmits information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, due to the propagation characteristics of RF signals through a multipath channel, a receiver may receive multiple "RF signals" corresponding to each transmitted RF signal. The same transmitted RF signal on different paths between the transmitter and the receiver may be referred to as a "multipath" RF signal. As used herein, an RF signal may also be referred to as a "wireless signal" or simply a "signal", where it is understood from the context that the term "signal" refers to a wireless signal or an RF signal.

[0038] According to various aspects, Figure 1FIG. 0 illustrates an example wireless communication system 100. The wireless communication system 100 (which may also be referred to as a wireless wide area network (WWAN)) may include various base stations 102 and various UEs 104. The base stations 102 may include macro cell base stations (high-power cellular base stations) and / or small cell base stations (low-power cellular base stations). On one hand, the macro cell base stations may include eNBs and / or ng-eNBs where the wireless communication system 100 corresponds to a Long Term Evolution (LTE) network, or gNBs where the wireless communication system 100 corresponds to a New Radio (NR) network, and / or a combination of both, and the small cell base stations may include femto cells, pico cells, micro cells, etc.

[0039] The base stations 102 may together form a RAN and interface with a core network 170 (e.g., an Evolved Packet Core (EPC) or a 5G Core (5GC)) via a backhaul link 122, and interface to one or more location servers 172 (which may be part of the core network 170 or may be external to the core network 170) via the core network 170. In addition to other functions, the base stations 102 may also perform functions related to one or more of the following: transmitting user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, radio access network information management (RIM), paging, positioning, and warning message passing. The base stations 102 may communicate with each other directly or indirectly (e.g., via the EPC / 5GC) via a backhaul link 134, which may be wired or wireless.

[0040] Base station 102 can communicate wirelessly with UE 104. Each of the base stations 102 can provide communication coverage for a corresponding geographical coverage area 110. On the one hand, one base station 102 in each geographical coverage area 110 can support one or more cells. A "cell" is a logical communication entity for communicating with a base station (e.g., via a certain frequency resource, referred to as a carrier frequency, component carrier, carrier, band, etc.), and can be associated with an identifier for distinguishing cells operating via the same or different carrier frequencies (e.g., physical cell identifier (PCI), virtual cell identifier (VCI), cell global identifier (CGI)). In some cases, different cells can be configured according to different protocol types that can provide access for different types of UEs (e.g., machine type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or other protocol types). Since a cell is supported by a specific base station, the term "cell" can refer to either or both of the logical communication entity and the base station that supports it, depending on the context. Additionally, since the TRP is typically the physical transmission point of a cell, the terms "cell" and "TRP" can be used interchangeably. In some cases, the term "cell" can also refer to the geographical coverage area of a base station (e.g., a sector), as long as the carrier frequency can be detected and used for communication within a certain part of the geographical coverage area 110.

[0041] Although the geographical coverage areas 110 of adjacent macro cell base stations 102 can partially overlap (e.g., in a handover area), some geographical coverage areas 110 can be substantially overlapped by a larger geographical coverage area 110. For example, a small cell base station 102' can have a geographical coverage area 110' that is substantially overlapped with the geographical coverage areas 110 of one or more macro cell base stations 102. A network including both small cells and macro cell base stations can be referred to as a heterogeneous network. A heterogeneous network can also include a home eNB (HeNB), which can provide services to a restricted group called a closed subscriber group (CSG).

[0042] The communication link 120 between the base station 102 and the UE 104 can include an uplink (also referred to as a reverse link) transmission from the UE 104 to the base station 102 and / or a downlink (also referred to as a forward link) transmission from the base station 102 to the UE 104. The communication link 120 can use MIMO antenna technologies including spatial multiplexing, beamforming, and / or transmit diversity. The communication link 120 can pass through one or more carrier frequencies. The carrier allocation can be asymmetric for the downlink and the uplink (e.g., more or fewer carriers can be allocated for the downlink compared to the uplink).

[0043] The wireless communication system 100 may also include a Wireless Local Area Network (WLAN) Access Point (AP) 150 that communicates with a WLAN Station (STA) 152 over a communication link 154 in an unlicensed frequency spectrum (e.g., 5 GHz). When communicating in the unlicensed frequency spectrum, the WLAN STA 152 and / or the WLAN AP 150 may perform a Clear Channel Assessment (CCA) or a Listen-Before-Talk (LBT) procedure before communication to determine whether the channel is available.

[0044] The small cell base station 102' may operate in licensed and / or unlicensed frequency spectrums. When operating in the unlicensed frequency spectrum, the small cell base station 102' may employ LTE or NR technologies and use the same 5 GHz unlicensed frequency spectrum used by the WLAN AP 150. The small cell base station 102' that employs LTE / 5G in the unlicensed frequency spectrum may increase the coverage of the access network and / or increase its capacity. NR in the unlicensed spectrum may be referred to as NR-U. LTE in the unlicensed frequency spectrum may be referred to as LTE-U, Licensed-Assisted Access (LAA), or MulteFire.

[0045] The wireless communication system 100 may also include a Millimeter Wave (mmW) base station 180 that may communicate with a UE 182 in mmW frequencies and / or near-mmW frequencies. Extremely High Frequency (EHF) is a part of RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. The radio waves in this band may be referred to as millimeter waves. Near-mmW may extend down to 3 GHz frequencies with a wavelength of 100 millimeters. The Super High Frequency (SHF) band extends between 3 GHz and 30 GHz and is also referred to as centimeter waves. Communication using the mmW / near-mmW radio frequency bands has high path loss and a relatively short range. The mmW base station 180 and the UE 182 may utilize beamforming (transmission and / or reception) on the mmW communication link 184 to compensate for the extremely high path loss and short range. Additionally, it should be understood that in an alternative configuration, one or more of the base stations 102 may also transmit using mmW or near-mmW and beamforming. Thus, it should be understood that the foregoing description is merely exemplary and should not be construed as limiting the various aspects disclosed herein.

[0046] Transmit beamforming is a technique used to focus RF signals in a specific direction. Conventionally, when a network node (e.g., a base station) broadcasts an RF signal, the network node broadcasts the signal in all directions (omnidirectionally). With transmit beamforming, the network node determines the location of a given target device (e.g., a UE) relative to the transmitting network node and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal to the receiving device. To change the directivity of the RF signal during transmission, the network node can control the phase and relative amplitude of the RF signal at each of one or more transmitters that are broadcasting the RF signal. For example, the network node can use an antenna array (referred to as a "phased array" or "antenna array") that generates a beam of RF waves that can be "steered" to point in different directions without actually moving the antennas. Specifically, RF currents from the transmitters are fed to the individual antennas with the correct phase relationships such that the radio waves from the individual antennas add together to increase radiation in the desired direction while canceling to suppress radiation in the undesired directions.

[0047] Transmit beams can be quasi-co-located, which means that they appear to have the same parameters to a receiver (e.g., a UE), regardless of whether the transmit antennas of the network node are physically co-located. In NR, there are four types of quasi-co-location (QCL) relationships. Specifically, a given type of QCL relationship means that certain parameters of a second reference RF signal on a second beam can be derived from information about a source reference RF signal on a source beam. Thus, if the source reference RF signal is of QCL type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay, and delay spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is of QCL type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is of QCL type C, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of a second reference RF signal transmitted on the same channel. If the source reference RF signal is of QCL type D, the receiver can use the source reference RF signal to estimate the spatial reception parameters of a second reference RF signal transmitted on the same channel.

[0048] In receive beamforming, the receiver uses receive beams to amplify RF signals detected on a given channel. For example, the receiver can increase the gain setting in a specific direction and / or adjust the phase setting of the antenna array to amplify the RF signal received from that direction (e.g., to increase its gain level). Thus, when the receiver is considered to be beamforming in a certain direction, this means that the beam gain in that direction is high relative to the beam gains in other directions, or the beam gain in that direction is the highest compared to the beam gains in the directions of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-noise interference ratio (SINR), etc.) of the RF signal received from that direction.

[0049] Receive beams can be spatially correlated. The spatial relationship means that the parameters of the transmit beam for the second reference signal can be derived from the information about the receive beam of the first reference signal. For example, a UE can use a specific receive beam to receive one or more reference downlink reference signals (e.g., positioning reference signal (PRS), tracking reference signal (TRS), phase tracking reference signal (PTRS), cell-specific reference signal (CRS), channel state information reference signal (CSI-RS), primary synchronization signal (PSS), secondary synchronization signal (SSS), synchronization signal block (SSB), etc.) from a base station. The UE can then form a transmit beam for sending one or more uplink reference signals (e.g., uplink positioning reference signal (UL-PRS), sounding reference signal (SRS), demodulation reference signal (DMRS), PTRS, etc.) to the base station based on the parameters of the receive beam.

[0050] Note that a "downlink" beam can be either a transmit beam or a receive beam, depending on the entity forming it. For example, if the base station is forming a downlink beam to transmit a reference signal to the UE, the downlink beam is a transmit beam. However, if the UE is forming a downlink beam, the downlink beam is a receive beam for receiving downlink reference signals. Similarly, an "uplink" beam can be either a transmit beam or a receive beam, depending on the entity forming it. For example, if the base station is forming an uplink beam, the uplink beam is an uplink receive beam, and if the UE is forming an uplink beam, the uplink beam is an uplink transmit beam.

[0051] In 5G, the frequency spectrum at which a wireless node (e.g., base station 102 / 180, UE 104 / 182) operates is divided into multiple frequency ranges: FR1 (from 450 MHz to 6000 MHz), FR2 (from 24250 MHz to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In a multi-carrier system such as 5G, one of the carrier frequencies is referred to as the "primary carrier" or "anchor carrier" or "primary serving cell" or "PCell", while the remaining carrier frequencies are referred to as "secondary carriers" or "secondary serving cells" or "SCells". In carrier aggregation, the anchor carrier is the carrier that operates on the primary frequency (e.g., FR1) utilized by either the UE 104 / 182 and the cell in which the UE 104 / 182 performs the initial radio resource control (RRC) connection establishment procedure or initiates the RRC connection re-establishment procedure. The primary carrier carries all common and UE-specific control channels and can be a carrier in an authorized frequency (however, this is not always the case). The secondary carrier is the carrier that operates on a second frequency (e.g., FR2) and can be configured and used to provide additional radio resources once an RRC connection is established between the UE 104 and the anchor carrier. In some cases, the secondary carrier can be a carrier in an unlicensed frequency. The secondary carrier can contain only necessary signaling information and signals. For example, UE-specific signaling information and signals may not be present in the secondary carrier because both the primary uplink and downlink carriers are typically UE-specific. This means that different UEs 104 / 182 in a cell can have different downlink primary carriers. The same applies to the uplink primary carrier. The network is able to change the primary carrier of any UE 104 / 182 at any time. For example, this is done to balance the load on different carriers. Since a "serving cell" (whether it is a PCell or an SCell) corresponds to the carrier frequency / component carrier on which communication is taking place at a certain base station, the terms "cell", "serving cell", "component carrier", "carrier frequency", etc. can be used interchangeably.

[0052] For example, still referring to Figure 1 , one of the frequencies utilized by the macro cell base station 102 can be the anchor carrier (or "PCell"), while the other frequencies utilized by the macro cell base station 102 and / or the mmW base station 180 can be secondary carriers ("SCells"). The simultaneous transmission and / or reception of multiple carriers enables the UE 104 / 182 to significantly increase its data transmission and / or reception rate. For example, compared to what is achieved by a single 20 MHz carrier, two 20 MHz aggregated carriers in a multi-carrier system would theoretically result in a two-fold increase in data rate (i.e., 40 MHz).

[0053] The wireless communication system 100 may also include a UE 164, which may communicate with the macro cell base station 102 via a communication link 120 and / or communicate with the mmW base station 180 via an mmW communication link 184. For example, the macro cell base station 102 may support a PCell and one or more SCell for the UE 164, and the mmW base station 180 may support one or more SCell for the UE 164.

[0054] The wireless communication system 100 may also include one or more UEs, such as UE 190, indirectly connected to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links (referred to as "side links"). In Figure 1 the example, the UE 190 has: a D2D P2P link 192 with one of the UEs 104 connected to one of the base stations 102 (e.g., the UE 190 may obtain cellular connectivity indirectly through this link); and a D2D P2P link 194 with a WLAN STA 152 connected to the WLAN AP 150 (the UE 190 may obtain WLAN-based Internet connectivity indirectly through this link). In the example, the D2D P2P links 192 and 194 may be supported by any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), etc.).

[0055] According to various aspects, Figure 2A An example wireless network structure 200 is shown. For example, the 5GC 210 (also referred to as the Next Generation Core (NGC)) may functionally be regarded as a control plane function 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and a user plane function 212 (e.g., UE gateway function, access to data networks, Internet Protocol (IP) routing, etc.), which cooperate to form a core network. The user plane interface (NG-U) 213 and the control plane interface (NG-C) 215 connect the gNB 222 to the 5GC 210, specifically to the control plane function 214 and the user plane function 212. In an additional configuration, the ng-eNB 224 may also be connected to the 5GC 210 via the NG-C 215 to the control plane function 214 and the NG-U 213 to the user plane function 212. In addition, the ng-eNB 224 may communicate directly with the gNB 222 via a backhaul connection 223. In some configurations, the new RAN 220 may have only one or more gNB 222s, while other configurations include one or more of both the ng-eNB 224 and the gNB 222s. Either the gNB 222 or the ng-eNB 224 may communicate with the UE 204 (e.g.,Figure 1 communicate with any one of the UEs depicted in 2 . Another optional aspect may include a location server 230 that may communicate with the 5GC 210 to provide location assistance for the UE 204. The location server 230 may be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules distributed across multiple physical servers, etc.), or alternatively may each correspond to a single server. The location server 230 may be configured to support one or more location services for the UE 204, which may be connected to the location server 230 via the core network, the 5GC 210, and / or via the Internet (not shown). Additionally, the location server 230 may be integrated into a component of the core network or alternatively may be external to the core network.

[0056] According to various aspects, Figure 2B Another example wireless network structure 250 is shown. For example, the 5GC 260 may functionally be considered to include a control plane function provided by the Access and Mobility Management Function (AMF) 264 and a user plane function provided by the User Plane Function (UPF) 262, which cooperate to form the core network (i.e., the 5GC 260). The user plane interface 263 and the control plane interface 265 connect the ng-eNB 224 to the 5GC 260 and specifically to the UPF 262 and the AMF 264, respectively. In an additional configuration, the gNB 222 may also be connected to the 5GC 260 via the control plane interface 265 to the AMF 264 and the user plane interface 263 to the UPF 262. Additionally, the ng-eNB 224 may communicate directly with the gNB 222 via the backhaul connection 223 with or without a direct gNB connectivity to the 5GC 260. In some configurations, the new RAN 220 may have only one or more gNBs 222, while other configurations include one or more of both the ng-eNB 224 and the gNB 222. The gNB 222 or the ng-eNB 224 may communicate with the UE 204 (e.g., Figure 1 any one of the UEs depicted in 2 ), which in the example of 2 is an autonomous or semi-autonomous vehicle. The base stations of the new RAN 220 communicate with the AMF 264 via the N2 interface and with the UPF 262 via the N3 interface.

[0057] ​​The functions of the AMF 264 include registration management, connection management, reachability management, mobility management, lawful interception, transmission of session management (SM) messages between the UE 204 and the session management function (SMF) 266, transparent proxy service for routing SM messages, access authentication and access authorization, transmission of short message service (SMS) messages between the UE 204 and the short message service function (SMSF) (not shown), and security anchor functionality (SEAF). The AMF 264 also interacts with the authentication server function (AUSF) (not shown) and the UE 204, and receives the intermediate key established due to the UE 204 authentication process. In the case of authentication based on a UMTS (Universal Mobile Telecommunications System) subscriber identity module (USIM), the AMF 264 retrieves the security material from the AUSF. The functions of the AMF 264 also include security context management (SCM). The SCM receives the key from the SEAF, which is used to derive the access network specific key. The functionality of the AMF 264 also includes location service management for regulatory services, transmission of location service messages between the UE 204 and the location management function (LMF) 270 (which acts as the location server 230), transmission of location service messages between the new RAN 220 and the LMF 270, allocation of evolved packet system (EPS) bearer identifiers for EPS interworking, and UE 204 mobility event notification. Additionally, the AMF 264 also supports the functionality of non-Third Generation Partnership Project (3GPP) access networks.

[0058] The functions of the UPF 262 include acting as an anchor for intra-RAT / inter-RAT mobility (when applicable), acting as an interconnection point for external protocol data unit (PDU) sessions with data networks (not shown), providing packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering), lawful interception (user plane collection), traffic usage reporting, quality of service (QoS) handling for the user plane (e.g., uplink / downlink rate enforcement, reflected QoS marking in the downlink), uplink traffic verification (service data flow (SDF) to QoS flow mapping), transport-level packet marking in the uplink and downlink, downlink packet buffering and downlink data notification triggering, and emitting and forwarding one or more "end markers" to the source RAN node. The UPF 262 can also support the conveyance of location service messages on the user plane between the UE 204 and a location server such as the secure user plane location (SUPL) positioning platform (SLP) 272.

[0059] The functions of the SMF 266 include session management, UE IP address allocation and management, selection and control of user plane functions, configuration of traffic steering at the UPF 262 for routing traffic to the correct destination, part of policy enforcement and control of QoS, and downlink data notification. The interface through which the SMF 266 communicates with the AMF 264 is referred to as the N11 interface.

[0060] Another optional aspect may include an LMF 270, which may communicate with the 5GC 260 to provide location assistance for the UE204. The LMF 270 may be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules distributed across multiple physical servers, etc.), or alternatively may each correspond to a single server. The LMF 270 may be configured to support one or more location services for the UE 204, which may be connected to the LMF 270 via the core network, the 5GC 260, and / or via the Internet (not shown). The SLP 272 may support similar functions to the LMF 270, but the LMF 270 may communicate with the AMF 264, the new RAN 220, and the UE 204 through the control plane (e.g., using interfaces and protocols intended to convey signaling messages rather than voice or data), while the SLP 272 may communicate with the UE 204 and external clients ( Figure 2B not shown in the figure) through the user plane (e.g., using protocols intended to carry voice and / or data, such as Transmission Control Protocol (TCP) and / or IP).

[0061] In one aspect, the LMF 270 and / or the SLP 272 may be integrated into a base station, such as the gNB 222 and / or the ng-eNB224. When integrated into the gNB 222 and / or the ng-eNB 224, the LMF 270 and / or the SLP272 may be referred to as a "location management component" or "LMC". However, as used herein, references to the LMF270 and the SLP 272 include both cases where the LMF 270 and the SLP 272 are components of the core network (e.g., the 5GC 260) and cases where the LMF 270 and the SLP 272 are components of a base station.

[0062] Autonomous and semi-autonomous driving safety technologies use a combination of hardware (sensors, cameras, and radars) and software to help vehicles identify certain safety risks so that they can warn the driver to take action (in the case of ADAS) or take action themselves (in the case of ADS) to avoid collisions. Vehicles equipped with ADAS or ADS include one or more camera sensors mounted on the vehicle that capture images of the scene in front of the vehicle (and possibly behind and on the sides of the vehicle). Radar systems can also be used to detect objects along the driving road (and possibly behind and on the sides of the vehicle). The radar system uses RF waves to determine the range, direction, speed, and / or altitude of an object along the road. More specifically, the transmitter emits pulses of RF waves that bounce off any object in their path. The pulses reflected back from the object return a small portion of the RF wave energy to the receiver, which is typically located at the same position as the transmitter. Cameras and radars are typically oriented to capture their respective versions of the same scene.

[0063] Processors such as digital signal processors (DSPs) within the vehicle analyze the captured camera images and radar frames and attempt to identify objects within the captured scene. Such objects can be other vehicles, pedestrians, road signs, objects, etc. within the driving road. Radar systems provide reasonably accurate measurements of object distance and speed under various weather conditions. However, radar systems typically have insufficient resolution to identify the characteristics of the detected objects. However, camera sensors typically do provide sufficient resolution to identify object characteristics. Cues about the shape and appearance of objects extracted from the captured images can provide features sufficient to classify different objects. Given the complementary properties of the two sensors, data from the two sensors can be combined (referred to as "fusion") in a single system for improved performance.

[0064] To further enhance ADAS and ADS systems, especially at level 3 and higher, autonomous and semi-autonomous vehicles can utilize high-definition (HD) map data sets that contain significantly more detailed information and absolute ground truth accuracy than those found in current conventional resources. Such HD maps can provide accuracy within an absolute range of 7 cm to 10 cm, a highly detailed inventory of all stationary physical assets related to the road (such as road lanes, road edges, shoulders, dividers, traffic signals, signs, painted markings, poles), and other data that can be used for safe navigation of roads and intersections by autonomous / semi-autonomous vehicles. HD maps can also provide electronic horizon prediction awareness, enabling autonomous / semi-autonomous vehicles to know what lies ahead.

[0065] Now refer to Figure 3, shows a vehicle 300 (referred to as "this vehicle" or "host vehicle") including a radar-camera sensor module 320, which is located in an interior compartment of the vehicle 300 behind the windshield 312. The radar-camera sensor module 320 includes a radar component configured to transmit radar signals through the windshield 312 in a horizontal coverage area 350 (shown by a dashed line) and receive reflected radar signals reflected from any object within the coverage area 350. The radar-camera sensor module 320 further includes a camera component for capturing an image based on light waves seen and captured through the windshield 312 in a horizontal coverage area 360 (shown by a dashed line).

[0066] Although Figure 3 an example is shown in which the radar component and the camera component are co-located components in a shared housing, it should be understood that they can be accommodated at different positions within the vehicle 300 respectively. For example, the camera can be positioned as Figure 3 shown, and the radar component can be located in the grille or front bumper of the vehicle 300. Additionally, although Figure 3 the radar-camera sensor module 320 is shown located behind the windshield 312, it alternatively can be located in a roof sensor array or elsewhere. Further, although Figure 3 only a single radar-camera sensor module 320 is shown, it should be understood that the vehicle 300 can have multiple radar-camera sensor modules 320 pointing in different directions (pointing to both sides, front, rear, etc.). The various radar-camera sensor modules 320 can be located below the "skin" of the vehicle (e.g., behind the windshield 312, doors, bumpers, grilles, etc.) or within a roof sensor array.

[0067] The radar-camera sensor module 320 can detect one or more objects (or no objects) relative to the vehicle 300. In Figure 3 the example, there are two objects: vehicles 330 and 340 within the horizontal coverage areas 350 and 360 that the radar-camera sensor module 320 can detect. The radar-camera sensor module 320 can estimate parameters (attributes) of the detected objects, such as position, range, direction, speed, size, classification (e.g., vehicle, pedestrian, road sign, etc.), etc. The radar-camera sensor module 320 can be employed on the vehicle 300 for automotive safety applications such as adaptive cruise control (ACC), forward collision warning (FCW), collision mitigation or avoidance via autonomous braking, lane departure warning (LDW), etc.

[0068] Collocating a camera and a radar allows these components to share electronics and signal processing and, in particular, enables early radar-camera data fusion. For example, the radar and the camera can be integrated onto a single board. A combined radar-camera alignment technique can be employed to align both the radar and the camera. However, collocating the radar and the camera is not required to practice the techniques described herein.

[0069] Figure 4 An on-board computer (OBC) 400 of a vehicle 300 in accordance with various aspects of the present disclosure is shown. In one aspect, the OBC 400 can be part of an ADAS or an ADS. The OBC 400 includes a non-transitory computer-readable storage medium (i.e., memory 404) and one or more processors 406 that communicate with the memory 404 via a data bus 408. The memory 404 includes one or more storage modules that store computer-readable instructions executable by the processor 406 to perform the functions of the OBC 400 described herein. For example, the processor 406 in combination with the memory 404 can implement the various operations described herein.

[0070] One or more radar-camera sensor modules 320 are coupled to the OBC 400 (only one is shown for simplicity in Figure 4 ). In some aspects, the radar-camera sensor module 320 includes at least one camera 412, at least one radar 414, and an optional light detection and ranging (LiDAR) sensor 416. The OBC 400 also includes one or more system interfaces 410 that connect the processor 406 to the radar-camera sensor module 320 and optionally to other vehicle subsystems (not shown) via the data bus 408.

[0071] At least in some cases, the OBC 400 also includes a wireless wide area network (WWAN) transceiver 430 configured to communicate via one or more wireless communication networks (not shown) such as an NR network, an LTE network, a global system for mobile communications (GSM) network, etc. The WWAN transceiver 430 can be connected to one or more antennas (not shown) to communicate with other network nodes (such as other vehicle UEs, pedestrian UEs, infrastructure access points, roadside units (RSUs), base stations (e.g., eNB, gNB), etc.) via at least one specified radio access technology (RAT) (e.g., NR, LTE, GSM, etc.) over an interested wireless communication medium (e.g., a set of time / frequency resources in a particular frequency spectrum). The WWAN transceiver 430 can be configured in different ways according to the specified RAT for transmitting signals (e.g., messages, indications, information, etc.) and encoding them, and conversely for receiving signals (e.g., messages, indications, information, pilots, etc.) and decoding them.

[0072] In at least some cases, the OBC 400 also includes a Wireless Local Area Network (WLAN) transceiver 440. The WLAN transceiver 440 can be connected to one or more antennas (not shown) to communicate with other network nodes (such as other vehicle UEs, pedestrian UEs, infrastructure access points, RSUs, etc.) via at least one specified Radio Access Technology (RAT) (such as Cellular Vehicle-to-Everything (C-V2X), IEEE 802.11p (also known as Wireless Access in Vehicular Environment (WAVE)), Dedicated Short Range Communications (DSRC), etc.) over an interested wireless communication medium. The WLAN transceiver 440 can be configured in different ways according to the specified RAT for transmitting signals (such as messages, indications, information, etc.) and encoding them, and conversely for receiving signals (such as messages, indications, information, pilots, etc.) and decoding them.

[0073] As used herein, a "transceiver" can include a transmitter circuit, a receiver circuit, or a combination thereof, but does not necessarily provide both transmit and receive functionality in all designs. For example, in some designs, a low-functionality receiver circuit (such as a receiver chip or a similar circuit that only provides low-level sniffing) can be employed to reduce costs when full communication is not required.

[0074] In at least some cases, the OBC 400 also includes a Global Positioning System (GPS) receiver 450. The GPS receiver 450 can be connected to one or more antennas (not shown) for receiving satellite signals. The GPS receiver 450 can include any suitable hardware and / or software for receiving and processing GPS signals. The GPS receiver 450 appropriately requests information and operations from other systems and performs the calculations required to determine the position of the vehicle 300 using measurements obtained through any suitable GPS algorithm.

[0075] On the one hand, the OBC 400 can utilize the WWAN transceiver 430 and / or the WLAN transceiver 440 to download one or more maps 402, which can then be stored in the memory 404 and used for vehicle navigation. The map 402 can be one or more High-Definition (HD) maps, which can provide accuracy within an absolute range of 7 cm to 10 cm, a highly detailed list of all stationary physical assets related to the road (such as road lanes, road edges, shoulders, dividers, traffic signals, signs, painted markings, poles), and other data that can be used for safe navigation of the road and intersections by the vehicle 300. The map 402 can also provide an electronic horizon prediction perception that enables the vehicle 300 to know the situation ahead.

[0076] On the one hand, the camera 412 can capture the visible area of the camera 412 at a certain periodic rate, such as Figure 3An image frame (also referred to herein as a camera frame) of a scene shown within a horizontal coverage area 360. Similarly, radar 414 may capture, at a certain periodic rate, a radar frame of a scene within the visible area of radar 414 (such as Figure 3 shown as a horizontal coverage area 350). The periodic rates at which camera 412 and radar 414 capture their respective frames may be the same or different. Each camera frame and radar frame may be timestamped. Thus, in the case where the periodic rates are different, the timestamps may be used to select, simultaneously or almost simultaneously, the captured camera frames and radar frames for further processing (e.g., fusion).

[0077] Figure 5 The sensed observed radar grid 500 is shown. A transmitter of radar 414 (e.g., a transmitting antenna array) transmits pulses of electromagnetic RF waves that are reflected from objects in the transmission path (such as Figure 3 vehicles 330 and 340 in). A portion of the electromagnetic RF waves reflected from the objects returns to a receiver of radar 414 (e.g., a receiving antenna array), which is typically located at the same site as the transmitter of radar 414.

[0078] On the one hand, radar 414 may be an imaging radar that scans horizontally and vertically using beamforming. Beamforming is a technique for aiming the effective direction of a radar beam by changing the delays between different transmitting antennas such that the signals constructively add in a specified direction. Thus, radar 414 may scan the sensing area (e.g., horizontal coverage area 350) horizontally and vertically by using a transmitter that includes an array of electronically steerable antennas.

[0079] The returned response measured by radar 414 (which may also be referred to as an "echo information (ping) of transmission") is characterized as an observation (or occupancy) grid 540 having a plurality of observation cells 542. Each cell 542 represents a returned response value measured at a specific range (r) and angle / azimuth (θ). Each cell 542 is alternatively referred to as a range-angle bin. Features 544 are extracted from cell 542 to determine whether feature 544 is an object (e.g., vehicle 330 / 340). Each feature 544 within the corresponding cell 542 may be identified as having up to four parameters: range, Doppler, azimuth, and height. This is referred to as a radar frame. As an example, the feature 544 within cell 542 may be a signal-to-noise ratio (SNR) calculated by a constant false alarm rate (CFAR) algorithm. However, it should be understood that other methods may be used to aim at and identify the features 544 within cell 542.

[0080] The processor 406 may generate a two-dimensional (2D), three-dimensional (3D), or four-dimensional (4D) tensor for features 544 within a cell 540 of an observation grid 540 detected by the radar 414. Specifically, the 2D tensor represents the range (distance from the vehicle 300 to the detected feature 544) and azimuth angle (horizontal distance between the feature 544 and a reference RF ray emitted by the radar 414, such as the initial RF ray of a radar sweep) of each detected feature 544. The 3D tensor represents the range, azimuth angle, and Doppler (indicating the speed of the detected feature 544) or altitude (vertical direction from the radar 414 to the detected feature) of each detected feature 544. The 4D tensor represents all four quantities. The processor 406 then performs object detection, object classification, localization, and property / attribute estimation based on the tensor and the undistorted camera frame received from the camera 412.

[0081] As more and more vehicles become autonomous or semi-autonomous, there will be a growing number of radar sources (e.g., radar 414) that need to coexist with each other. However, multiple radar sources may cause severe interference, which is particularly problematic for accurate target detection. Conventional radar waveforms may not be distinguishable even when transmitted from different sources. Thus, other radar sources appear as "ghost" targets (i.e., detected objects that do not correspond to physical target objects) to the present vehicle (e.g., vehicle 300). Additionally, the high interference from the direct (interference) path may be much stronger than the signal strength of the reflected (desired) path (R 2 relative to R 4 attenuation). This is described below with reference to Figure 6A and 6B for.

[0082] Frequency-modulated continuous-wave (FMCW) radar is a conventional radar with the above-mentioned drawbacks. FMCW radar is a short-range measurement radar that can provide distance measurement to a target object as well as speed measurement of the target object. FMCW uses a transmitted signal of a known stable frequency continuous wave that changes frequency within a fixed time period by a modulation signal. The frequency difference between the received (reflected) signal and the transmitted signal increases with the delay and thus with the distance. This erases or blurs the Doppler signal. Then the echo from the target object is mixed with the transmitted signal to generate a beat frequency signal, which provides the distance to the target object after demodulation.

[0083] Figure 6A is a schema 600 showing an example of the present vehicle 610 and two target vehicles 620 and 630 in accordance with various aspects of the present disclosure. In Figure 6AIn the example, both the host vehicle 610 and the target vehicle 620 are equipped with radar sensors (e.g., radar 414) and can thus be examples of vehicle 300. The target vehicle 630 may not be equipped with a radar sensor and can thus be an example of vehicle 330 or 340. As Figure 6A shown, the host vehicle 610 uses its radar sensor to detect both target vehicles 620 and 630, as shown by the round-trip line labeled "Reflected signal from target". However, because the target vehicle 620 is also a radar source, the host vehicle 610 directly receives radar signals from the target vehicle 620, as shown by the black arrow labeled "Interference". This can cause the host vehicle 610 to determine that there is a third target vehicle (the "phantom" target) at half the distance to the actual target vehicle 620 (because the host vehicle 610 interprets the radar signal received from the target vehicle 620 as having traveled from the host vehicle 610 to the phantom target and back in the actual time it takes for the received signal to travel from the target vehicle 620 to the host vehicle 610). To prevent this false detection, the host vehicle 610 can increase the background noise (the signal strength threshold below which the host vehicle will ignore reflections) to eliminate the detection of the phantom target. However, as Figure 6B shown, this may potentially result in the failure to detect the real target.

[0084] Figure 6B Graph 650 is an example showing how much higher the received power of the direct radar signal can be than the received power of the reflected radar signal. For example, referring to Figure 6A , if the target vehicle 620 is 140.3 meters (m) away from the host vehicle 610, the received power of the radar signal directly received from the target vehicle 620 can be -57.06 decibel-milliwatts (dBm), while the received power of the reflected radar signal (i.e., the reflection of the radar signal transmitted by the host vehicle 610) can be -111 dBm. If the host vehicle 610 increases the background noise (shown as T c = 25 μs or T c = 25 μs plus SNR) to eliminate the detection of the radar signal following the direct path, it will also eliminate the detection of the radar signal following the reflected path.

[0085] Figure 7A and 7B show examples of the impact of multi-radar interference on radar performance. Figure 7A Schema 700 is a diagram showing an example of the host vehicle 710 and multiple target vehicles 720a-d (collectively referred to as target vehicles 720), which is similar to a National Highway Traffic Safety Administration (NHTSA) scenario. In Figure 7A the example, each target vehicle 720a-d is also a radar source and is thus a source of interference. Therefore, Figure 7AEach vehicle shown can be an example of vehicle 300.

[0086] Figure 7B is a graph 750 showing examples of target false detection probabilities in different ranges (in meters). Graph 750 shows the false detection results for a scenario similar to that in Figure 7A , except that there are 23 interference sources in the relative traffic lane. That is, in the scenario shown in Figure 7B , there are 23 interfering vehicles 720 in the relative lane instead of Figure 7A the only 4 vehicles approaching the host vehicle 710 as shown in

[0087] In graph 750, the vertical dashed lines show the ranges within which the host vehicle (e.g., host vehicle 710) can detect a given type of target (i.e., pedestrian, car, truck) if there is no interference. The solid curves show the probability of false detection at different ranges in the presence of interference. As shown in graph 750, at a 10% false detection probability, there is approximately a 43% to 53% loss in the radar detection range. If higher reliability (lower false detection) is required, this range loss is even greater.

[0088] Coordinating the selection of FMCW parameters among radar sources (e.g., autonomous vehicles) can significantly improve target (false) detection performance. For example, options for radar parameters such as time, slope, and frequency offset can minimize interference with each other. Figure 8 is a graph 800 showing examples of false detection probabilities in different ranges (in meters). Graph 800 shows the false detection results for a scenario similar to that in Figure 7B , where there are 23 interference sources in the traffic lane opposite the host vehicle. That is, the test scenario is similar to the scenario shown in Figure 7A , except that there are 23 interfering vehicles 720 in the relative lane instead of Figure 7A the only 4 vehicles approaching the host vehicle 710 as shown in

[0089] In graph 800, the dashed curves show the probability of false detection at different ranges in the presence of interference when there is no coordination among the radar sources (i.e., the radar parameters are not coordinated). These curves correspond to the curves shown in graph 750 in Figure 7B , and as in Figure 7B, which shows the false detection probabilities for different types of targets (i.e., pedestrians, cars, trucks). The solid curves show the probabilities of false detection at different ranges in the presence of coordination (i.e., radar parameter coordination). As shown in graph 800, at a false detection probability of 10%, the detection ranges for pedestrians and cars increase by approximately 50%, while the detection range for trucks increases by approximately 20%.

[0090] In view of the benefits of coordinating radar parameters between radar sources (e.g., autonomous vehicles), the present disclosure provides techniques for enabling such coordination. To coordinate the selection of radar parameters by different vehicles, the vehicles need to be able to communicate with each other to negotiate the radar parameters. However, not all radar sources that are close to each other may interfere with each other, depending on the frequency bands, parameters, etc. used. Thus, reactive communication and coordination would be beneficial, and only those vehicles whose current radar transmissions significantly affect the performance of this radar need to communicate with each other if certain vehicles' current radar transmissions significantly affect the performance of this radar. However, the problem is to identify vehicles by observing only their radar transmissions.

[0091] Therefore, the present disclosure provides techniques for embedding information data bits such as vehicle identifiers (IDs) (e.g., license plate numbers, vehicle identification numbers (VINs), UE IDs, etc.) in radar transmissions (e.g., FMCW radar), which can be estimated / determined at a receiving radar sensor (e.g., radar 414). The determined vehicle ID can then be used to establish communication with interfering vehicles on different channels (e.g., using V2X communication).

[0092] On the one hand, a radar (e.g., radar 414) can encode the information data bits and embed them as phase codes on FMCW. The information data bits can be a vehicle ID, which can be used to address the transmitting vehicle to attempt to establish a connection with it. The information data bits can be encoded (e.g., polar encoding or low-density parity-check (LDPC) encoding) and can be appended with a cyclic redundancy check (CRC).

[0093] For example, assume a set of decoded bits is represented as {c0, c1, … c N}. On the one hand, the number of decoded bits to be transmitted (i.e., N) can be determined as a function of the number of chirps, the number of known reference symbols, and the phase shift keying (PSK) modulation order (i.e., PSK, binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), 8-PSK, etc.). For example, if the number of chirps is represented as Nc, the number of chirps with known phase modulation is represented as Nc1, and the PSK modulation order (i.e., 1, 2, 4, 8, etc.) is represented as Q, then the number of decoded bits that can be transmitted can be determined as N = (Nc - Nc1) * Q.

[0094] Then, phase - decoded symbols {s1, s2, … s (Nc-Nc1)} modulated by PSK can be generated to convey information data bits. For example, for QPSK modulation, based on {c k / 2 , c k / 2+1}, s k = exp(±1i*π / 4) or exp(±1i*3*π / 4). Additionally, PSK - modulated symbols d = {d1, d2, … d (Nc1)} can be generated as known phase - reference symbols known to other vehicles.

[0095] Note that PSK is a digital modulation process that conveys data by changing (modulating) the phase of a constant - frequency reference signal (carrier). Each of a finite number of phases (e.g., 2, 4, 8) represents a specific symbol. For example, BPSK uses two phases that can represent two symbols, QPSK uses four phases that can represent four symbols, and 8 - PSK uses eight phases that can represent eight symbols. The demodulator (receiver) determines the phase of the received signal and maps it back to the symbol it represents, thus recovering the original data.

[0096] The FMCW waveform can be phase - decoded according to (e.g., based on) the phase - decoded symbols s and d described above. For example, assume the following parameters:

[0097] K = Nc / Nc1

[0098] Chirp set = {1:Nc}

[0099] Sub - set 1 = {1:K:Nc}

[0100] Sub - set 2 = Chirp set minus Sub - set 1

[0101] For the Sub - set 1 chirps, the FMCW waveform can be phase - modulated using d k , where d k is known to other vehicles and used as a reference symbol. For the Sub - set 2 chirps, the FMCW waveform can be phase - modulated using s kPhase modulation is performed. Even if the chirp is phase coherent, the reason for using reference symbols is that the phase noise variation of the phase-locked loop (PLL) between this vehicle and the interfering vehicle will introduce phase changes across the chirps (the changes within a chirp are small). These phase changes need to be estimated, which can be done using reference symbols. Typically, the transmitter vehicle can interleave known phases (reference symbols) every K chirps (e.g., K = 2). The use of these reference symbols is similar to the use of phase-tracking reference signals (PTRS) in the 5G NR Uu interface (the air interface between the UE and the gNB) for phase tracking. The radar (e.g., radar 414) of the transmitter vehicle (e.g., this vehicle 610, target vehicle 620) can then transmit Nc chirps of the phase-modulated FMCW waveform as its radar signal.

[0102] As a specific example, if Nc = 128, which means there are 128 chirps or 128 bits for each radar transmission, and K = 2, then 64 chirps will be used as reference symbols ("subset 1" chirps), and the remaining 64 chirps will be used for information data bits ("subset 2" chirps), such as vehicle IDs.

[0103] On the receiver side (e.g., target vehicle 620, or this vehicle 610 when receiving the radar signal from target vehicle 620), the receiving radar receives the radar signal transmitted by another radar source by tuning to the FMCW parameters used by the other radar source. On the one hand, the set of potential FMCW parameters that a given radar can use can be pre-configured in the radar (e.g., based on the applicable wireless communication standard). In this way, when the radar is interfered with by another vehicle, it can tune to different pre-configured FMCW parameters until it can decode the received radar signal.

[0104] The receiving radar can use the observed phases of the subset of chirps carrying reference symbols (e.g., "subset 1" chirps) to determine the random phase difference between the receiving radar and the transmitting (interfering) radar. The receiving radar can use the determined random phase difference to equalize the determined phase difference of the subset 1 chirps. The receiving radar can then determine the Doppler and phase codes on the subset of chirps carrying information data bits (e.g., "subset 2" chirps) and decode and determine the information data bits (e.g., vehicle ID). In the case where the information bit indicates the ID of the transmitting vehicle, the receiving vehicle can use the determined vehicle ID to communicate with other vehicles (i.e., the transmitting / interfering vehicle). Specifically, the receiving vehicle can attempt to establish a vehicle-to-vehicle (V2V) or V2X communication session (e.g., sidelink) with the transmitting (interfering) vehicle.

[0105] Figure 9AFIG. is a diagram of an example of a transmitter-side phase-decoded phase-modulated continuous wave (FMCW) waveform 900 in accordance with various aspects of the present disclosure. Figure 9B FIG. is a diagram of an example of a receiver-side phase-decoded PMCW waveform 950 in accordance with various aspects of the present disclosure. In Figure 9A and 9B where Q is the PSK modulation order (e.g., 2, 4, 8), i and j represent the square root of -1, lambda (λ) is the wavelength, d k is a reference chirp / symbol (e.g., “subset 2” chirp), s k is a chirp / symbol that conveys information data bits (e.g., “subset 2” chirp), and Tc is the background noise (threshold). For d k k is an index from 1 to Nc - Nc1, where Nc is the total number of chirps and Nc1 is the number of chirps with known phase modulation. For s k k is an index from 1 to Nc1. In Figure 9A where is the phase noise of the mth chirp at the transmitter (Tx). In Figure 9B where is the phase noise of the mth chirp at the receiver (Rx).

[0106] Figure 10 FIG. illustrates an example method 1000 of transmitting multiple encoded information bits on a radar signal. Method 1000 may be performed by a transmitter radar such as radar 414. In one aspect, radar 414 may be considered a component for performing each operation of method 1000.

[0107] At 1010, radar 414 generates a first set of PSK-modulated phase-decoded symbols to convey multiple encoded information bits.

[0108] At 1020, radar 414 generates a second set of PSK-modulated phase-decoded symbols as reference symbols with known phase modulation.

[0109] At 1030, radar 414 phase-decodes multiple chirps of the radar signal based on the first set of PSK-modulated phase-decoded symbols and the second set of PSK-modulated phase-decoded symbols, as described above with reference to Figure 9A and 9B For example, a portion of the multiple chirps may be phase-decoded according to the first set, and the remaining chirps of the multiple chirps may be phase-decoded according to the second set.

[0110] At 1040, radar 414 transmits the multiple chirps of the radar signal according to the phase decoding.

[0111] Figure 11 Illustrates an example method 1100 for receiving multiple encoded information bits on a radar signal. Method 1100 may be performed by a receiver radar such as radar 414. In one aspect, radar 414 may be considered a component for performing each operation of method 1100.

[0112] At 1110, radar 414 receives multiple chirps of a radar signal from a transmitter radar, wherein the multiple chirps of the radar signal are phase decoded according to a first set of PSK-modulated phase decoded symbols and a second set of PSK-modulated phase decoded symbols, wherein the first set of PSK-modulated phase decoded symbols conveys multiple encoded information bits, and wherein the second set of PSK-modulated phase decoded symbols is a reference symbol with a known phase modulation.

[0113] At 1120, radar 414 determines a phase difference between the receiver radar and the transmitter radar based on the phases of the multiple chirps of the radar signal phase decoded according to the second set of PSK-modulated phase decoded symbols.

[0114] At 1130, radar 414 equalizes the phases of the multiple chirps of the radar signal based on the determined phase difference.

[0115] At 1140, radar 414 determines a phase code of the first set of PSK-modulated phase decoded symbols based on the equalized phases of the multiple chirps.

[0116] At 1150, radar 414 decodes the multiple encoded information bits based on the phase code of the first set of PSK-modulated phase decoded symbols.

[0117] As will be appreciated, the technical advantages of methods 1000 and 1100 are that: the transmitter radar can encode information (e.g., vehicle ID) in its radar signal, and the receiver radar can decode the information. This enables the transmitter and receiver to coordinate subsequent communications with each other to, for example, establish a sidelink, coordinate radar parameters, and thereby reduce interference between each other.

[0118] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is illustrative of example methods. Based on design preferences, it should be understood that the specific order or hierarchy of the blocks in the process / flowchart can be rearranged. Additionally, some blocks may be combined or omitted. The appended method claims present the elements of the various blocks in a sample order, and this is not meant to be limiting to the specific order or hierarchy presented.

[0119] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein but are to be accorded the full scope consistent with the language of the claims, where the reference to an element in the singular is not intended to mean "one and only one" (unless specifically so stated) but rather "one or more." The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term "some" means one or more.

[0120] It should be understood that any reference herein to an element using designations such as "first," "second," etc., generally does not limit the number or order of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements may be employed herein, or that the first element must in some way precede the second element.

[0121] Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" include any combination of A, B, and / or C, and may include multiple As, multiple Bs, or multiple Cs. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combination may include one or more members of one or more of A, B, or C. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known or later become known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims.

[0122] In addition, nothing disclosed herein is dedicated to the public, whether or not the disclosure is explicitly recited in the claims. The words "module," "mechanism," "element," "device," etc., may not be substitutes for the word "component." Thus, no claim element should be construed as a means-plus-function unless the element is expressly recited using the phrase "means for...".

Claims

1. A device, comprising: a receiving radar configured to: receive a plurality of chirps of a radar signal from a transmitting radar, wherein the plurality of chirps of the radar signal are phase decoded according to a first set of phase decoded symbols modulated by phase shift keying (PSK) and a second set of phase decoded symbols modulated by PSK, wherein the first set of phase decoded symbols modulated by PSK conveys a plurality of encoded information bits, and wherein the second set of phase decoded symbols modulated by PSK are reference symbols with known phase modulation; determine a phase difference between the receiving radar and the transmitting radar based on the phases of the plurality of chirps of the radar signal phase decoded according to the second set of phase decoded symbols modulated by PSK; equalize the phases of the plurality of chirps of the radar signal based on the determined phase difference; determine a phase code of the first set of phase decoded symbols modulated by PSK based on the equalized phases of the plurality of chirps; and decode the plurality of encoded information bits based on the phase code of the first set of phase decoded symbols modulated by PSK.

2. The device according to claim 1, wherein the number of phase decoded symbols modulated by PSK in the first set is equal to the number of the plurality of chirps of the radar signal minus the number of phase decoded symbols modulated by PSK in the second set.

3. The device according to claim 1, wherein the number of the plurality of encoded information bits is expressed as (Nc - Nc1)*Q, where Nc is the number of the plurality of chirps of the radar signal, Nc1 is the number of phase decoded symbols modulated by PSK in the second set, and Q is the PSK modulation order.

4. The device according to claim 1, wherein: a first set of chirps of the plurality of chirps of the radar signal is phase decoded according to the first set of phase decoded symbols modulated by PSK; and a second set of chirps of the plurality of chirps of the radar signal is phase decoded according to the second set of phase decoded symbols modulated by PSK.

5. The device according to claim 4, wherein the first set of chirps of the plurality of chirps of the radar signal is interleaved with the second set of chirps of the plurality of chirps of the radar signal.

6. The apparatus according to claim 4, wherein according to phase decoding is performed on the first set of chirps among the plurality of chirps of the radar signal, where s k is the k-th symbol of the first set of PSK-modulated phase decoding symbols, which is modulated to the m-th chirp of the plurality of chirps, j represents the square root of -1, is the phase noise of the m-th chirp at the receiver radar, and is the phase noise of the m-th chirp at the transmitter radar.

7. The apparatus according to claim 4, wherein according to phase decoding is performed on the second set of chirps among the plurality of chirps of the radar signal, where d k is the k-th symbol of the second set of PSK-modulated phase decoding symbols, which is modulated to the m-th chirp of the plurality of chirps, j represents the square root of -1, is the phase noise of the m-th chirp at the receiver radar, and is the phase noise of the m-th chirp at the transmitter radar.

8. The device according to claim 1, wherein the radar signal is received from a radar of an autonomous or semi-autonomous vehicle.

9. The device according to claim 8, wherein the plurality of encoded information bits includes an identifier of the autonomous or semi-autonomous vehicle.

10. The device according to claim 9, wherein the identifier includes a license plate number of the autonomous or semi-autonomous vehicle, a vehicle identification number (VIN) of the autonomous or semi-autonomous vehicle, or a user equipment (UE) identifier associated with the autonomous or semi-autonomous vehicle.

11. The device according to claim 9, further comprising: A transceiver configured to establish a sidelink with the autonomous or semi-autonomous vehicle based on the identifier to coordinate radar transmissions between the autonomous or semi-autonomous vehicle and the receiver radar.

12. The apparatus according to claim 1, wherein the receiver radar includes a radar of an autonomous or semi-autonomous vehicle.

13. The apparatus according to claim 1, wherein the receiver radar is further configured to: Determine the Doppler of the first set of phase decoded symbols modulated by PSK based on the equalized phases of the multiple chirps of the radar signal.

14. A method of receiving multiple encoded information bits on a radar signal performed by a receiver radar, comprising: Receiving multiple chirps of the radar signal from a transmitter radar, wherein the multiple chirps of the radar signal are phase decoded according to a first set of phase decoded symbols modulated by phase shift keying (PSK) and a second set of phase decoded symbols modulated by PSK, wherein the first set of phase decoded symbols modulated by PSK conveys the multiple encoded information bits, and wherein the second set of phase decoded symbols modulated by PSK is a reference symbol with a known phase modulation; Determining a phase difference between the receiver radar and the transmitter radar based on the phases of the multiple chirps of the radar signal phase decoded according to the second set of phase decoded symbols modulated by PSK; Equalizing the phases of the multiple chirps of the radar signal based on the determined phase difference; Determining a phase code of the first set of phase decoded symbols modulated by PSK based on the equalized phases of the multiple chirps; And Decoding the multiple encoded information bits based on the phase code of the first set of phase decoded symbols modulated by PSK.

15. The method according to claim 14, wherein the number of the multiple encoded information bits is expressed as (Nc - Nc1) * Q, where Nc is the number of the multiple chirps of the radar signal, Nc1 is the number of the phase decoded symbols modulated by PSK in the second set, and Q is the PSK modulation order.

16. The method according to claim 14, wherein: Phase decoding a first set of chirps of the multiple chirps of the radar signal according to the first set of phase decoded symbols modulated by PSK; and Phase decoding a second set of chirps of the multiple chirps of the radar signal according to the second set of phase decoded symbols modulated by PSK.

17. The method according to claim 16, wherein the first set of chirps of the multiple chirps of the radar signal is interleaved with the second set of chirps of the multiple chirps of the radar signal.

18. The method according to claim 16, wherein according to phase decoding is performed on the first set of chirps among the plurality of chirps of the radar signal, where s k is the k-th symbol of the first set of PSK-modulated phase decoding symbols, which is modulated to the m-th chirp of the plurality of chirps, j represents the square root of -1, is the phase noise of the m-th chirp at the receiver radar, and is the phase noise of the m-th chirp at the transmitter radar.

19. The method according to claim 16, wherein according to phase decoding is performed on the second set of chirps among the plurality of chirps of the radar signal, where d k is the k-th symbol of the second set of PSK-modulated phase decoding symbols, which is modulated to the m-th chirp of the plurality of chirps, j represents the square root of -1, is the phase noise of the m-th chirp at the receiver radar, and is the phase noise of the m-th chirp at the transmitter radar.

20. A computer-readable medium having program code stored thereon, wherein the program code is executable by one or more processors of a receiver to cause the processors to perform the method of receiving multiple encoded information bits on a radar signal performed by a receiver radar according to any one of claims 14 - 19.

21. A computer program product comprising computer-readable instructions that, when executed by a processor, cause the processor to perform the method of receiving a plurality of encoded information bits on a radar signal by a receiver radar as recited in any one of claims 14-19.

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