Radar Coexistence Methods

Abstract

A method and apparatus for selecting frequency modulated continuous wave waveform parameters for coexistence of multiple radars by a user device is described. The user device may transmit a radar waveform composed of a plurality of linear frequency modulated pulses, wherein each linear frequency modulated pulse has the same duration. The user device may change the waveform parameters of the radar waveform for at least a subset of the plurality of linear frequency modulated pulses, wherein the waveform parameters may be selected from a codebook including at least one codeword for the parameters. A reflected radar waveform is received and processed, wherein the processing includes applying a fast-time discrete Fourier transform to the reflected radar waveform to generate a one-dimensional peak in a time delay dimension for each reflected waveform; and applying a slow-time discrete Fourier transform to the reflected radar waveform, wherein the peaks for the reflected waveform are added.

Description

[0001] Cross-references

[0002] This patent application claims the benefit of U.S. Patent Application No. 16 / 512,267, filed on July 15, 2019, by Gulati et al., entitled “Methods For Radar Coexistence,” and U.S. Provisional Patent Application No. 62 / 703,290, filed on July 25, 2018, by Gulati et al., entitled “Methods for Radar Coexistence,” each of which is assigned to the present assignee.

[0003] Introduction

[0004] The following generally involves selecting waveform parameters for multiple radar coexistence and processing reflected radar waveforms by equalizing and resampling the reflected radar waveforms.

[0005] Radar systems are used for target detection by transmitting a radio frequency waveform and observing the received waveform reflected from the target to estimate the properties of the target, such as the target's range, velocity, and angular position. Radar systems are widely used for detection of aircraft, ships, vehicles, weather formations, terrain, etc. Examples of transmitted radio frequency waveforms used in radar systems may include frequency modulated continuous wave (FMCW), phase modulated continuous wave (PMCW), etc.

[0006] Radar can be used as a sensor input in vehicles to enable advanced driver assistance systems (ADAS) and autonomous driving. However, radar transmissions from nearby vehicles can cause significant interference to other radar systems and can degrade object detection performance. Summary of the invention

[0007] The present disclosure relates to methods, systems, devices, and apparatus for selecting frequency modulated continuous wave waveform parameters for multiple radar coexistence. A method for selecting waveform parameters for multiple radar coexistence by a user equipment (UE) is described. In one example, the method and apparatus may include the UE sending a radar waveform consisting of multiple linear frequency modulation pulses (chirps), wherein each linear frequency modulation pulse has the same duration. The UE may change the waveform parameters of the radar waveform for at least a subset of the multiple linear frequency modulation pulses, wherein the waveform parameters are selected from a codebook including at least one codeword of the parameters. The UE may then receive and process the reflected radar waveform.

[0008] A method implemented by a UE for detecting a target using a radar signal is described. The method may include: selecting a waveform parameter set for transmitting a corresponding set of chirp pulses associated with a radar waveform from a codebook of waveform parameters; transmitting the chirp pulse set according to the corresponding waveform parameter set; receiving a reflected radar waveform including a reflected chirp pulse set corresponding to the chirp pulse set from a target; and processing the reflected radar waveform based on the waveform parameter set.

[0009] An apparatus implemented by a UE for detecting a target using a radar signal is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor to cause the apparatus to: select a waveform parameter set for transmitting a corresponding linear frequency modulation pulse set associated with a radar waveform from a codebook of waveform parameters; transmit the linear frequency modulation pulse set according to the corresponding waveform parameter set; receive a reflected radar waveform including a reflected linear frequency modulation pulse set corresponding to the linear frequency modulation pulse set from a target; and process the reflected radar waveform based on the waveform parameter set.

[0010] Another apparatus implemented by a UE for detecting a target using a radar signal is described. The apparatus may include components for: selecting a waveform parameter set for transmitting a corresponding chirp set associated with a radar waveform from a codebook of waveform parameters; transmitting the chirp set according to the corresponding waveform parameter set; receiving a reflected radar waveform including a reflected chirp set corresponding to the chirp set from a target; and processing the reflected radar waveform based on the waveform parameter set.

[0011] A non-transitory computer-readable medium is described, which stores code for detecting a target using a radar signal implemented by a UE. The code may include instructions executable by a processor to: select a waveform parameter set for transmitting a corresponding chirp set associated with a radar waveform from a codebook of waveform parameters; transmit the chirp set according to the corresponding waveform parameter set; receive a reflected radar waveform including a reflected chirp set corresponding to the chirp set from a target; and process the reflected radar waveform based on the waveform parameter set.

[0012] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, the set of waveform parameters includes at least three different waveform parameters.

[0013] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, selecting the set of waveform parameters from the codebook includes randomly selecting the set of waveform parameters from the codebook.

[0014] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, a set of waveform parameters includes a set of waveform parameter pairs, each waveform parameter pair including a chirp slope and a frequency offset.

[0015] In one example of the methods, apparatus, and non-transitory computer readable media described herein, transmitting the set of chirps according to the set of waveform parameters includes transmitting each chirp in the set of chirps according to a different pair of waveform parameters than a previous chirp.

[0016] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: sending a first linear frequency modulation pulse in a linear frequency modulation pulse set according to a first waveform parameter pair in a waveform parameter set; and sending a second linear frequency modulation pulse in the linear frequency modulation pulse set continuously with the first linear frequency modulation pulse according to a second waveform parameter pair in the waveform parameter set that is different from the first waveform parameter pair.

[0017] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for transmitting a third chirp in the set of chirps according to a third waveform parameter pair different from a second waveform parameter pair in the set of waveform parameters.

[0018] In one example of the methods, apparatus, and non-transitory computer readable media described herein, transmitting the third chirp includes transmitting the third chirp consecutively to the second chirp.

[0019] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, each chirp slope depends on a corresponding first parameter, and each frequency offset depends on a corresponding first parameter and a corresponding second parameter.

[0020] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions wherein each waveform parameter pair satisfies the following parameterized relationship:

[0021] parameter:

[0022] where β (m) is the linear frequency modulation pulse slope, f 0 (m) is the frequency offset, q (m) is the first parameter, u (m) is the second parameter, B is the frequency range of each chirp in the chirp set, and T cis the time period of each chirp in the set of chirp pulses.

[0023] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include BT c An operation, feature, component, or instruction that can be a prime number.

[0024] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: applying phase modulation to two or more linear frequency modulation pulses in a linear frequency modulation pulse set before transmitting the two or more linear frequency modulation pulses to reduce coherent addition between linear frequency modulation pulses transmitted according to the same waveform parameters in the linear frequency modulation pulse set.

[0025] In one example of the methods, apparatuses, and non-transitory computer readable media described herein, each chirp in the set of chirp pulses corresponds to a chirp having the same constant time period T c Loop of the radar waveform.

[0026] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, each reflected linear frequency chirp in the set of reflected linear frequency chirp pulses corresponds to a transmitted linear frequency chirp in the set of linear frequency chirp pulses and can be associated with the same waveform parameters as the corresponding transmitted linear frequency chirp, and wherein processing the reflected radar waveform can include operations, features, components, or instructions for: identifying a peak in a time delay dimension corresponding to a range to a target based on a first reflected linear frequency chirp associated with a first waveform parameter in the set of waveform parameters, and identifying a peak in a Doppler dimension corresponding to a Doppler of the target based on the first reflected linear frequency chirp and a second reflected linear frequency chirp associated with a second waveform parameter in the set of waveform parameters.

[0027] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, processing a reflected radar waveform may include operations, features, components, or instructions for: applying a first Fourier transform to a first reflected linear frequency chirp to identify a peak in a time delay dimension, and applying a second Fourier transform to the first reflected linear frequency chirp and a second reflected linear frequency chirp to identify a peak in a Doppler dimension.

[0028] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, processing a reflected radar waveform may include operations, features, components, or instructions for: applying a third Fourier transform to a second reflected linear frequency modulation pulse and equalizing a first phase of the first reflected linear frequency modulation pulse and a second phase of the second reflected linear frequency modulation pulse before applying a second Fourier transform.

[0029] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, processing a reflected radar waveform may include operations, features, components, or instructions for: resampling a first reflected linear frequency chirp and a second reflected linear frequency chirp after applying a first Fourier transform and a third Fourier transform to align outputs of the first Fourier transform and the third Fourier transform before applying a second Fourier transform.

[0030] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, the radar waveform may be a frequency modulated continuous wave (FMCW) waveform.

[0031] In one example of the methods, apparatus, and non-transitory computer-readable media described herein, the radar waveform may be a phase-coded frequency modulated continuous wave (FMCW) waveform. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 An example wireless network in accordance with aspects of the present disclosure is shown.

[0033] Figure 2 An example logical architecture of a distributed radio access network (RAN) according to aspects of the present disclosure is shown.

[0034] Figure 3 An example physical architecture of a distributed RAN according to aspects of the present disclosure is shown.

[0035] Figure 4 Example components of a base station and a user equipment (UE) in a wireless communication system according to aspects of the present disclosure are shown.

[0036] Figure 5A Examples of downlink (DL)-centric subframes in accordance with aspects of the present disclosure are shown.

[0037] Figure 5B Examples of uplink (UL)-centric subframes are shown in accordance with aspects of the present disclosure.

[0038] Fig. 6A An example wireless communication system in accordance with aspects of the present disclosure is shown.

[0039] Figure 6B An example graph illustrating received power of direct and reflected signals over distance is shown in accordance with aspects of the present disclosure.

[0040] Fig. 7A and Figure 7B A frequency-time graph of a frequency modulated continuous wave (FMCW) in accordance with aspects of the present disclosure is shown. Fig. 7Ashows the unchanged waveform parameters, while Figure 7B Changes in the slope β and / or frequency offset f parameters are shown.

[0041] Figure 7C Examples of signal processing according to aspects of the present disclosure are shown.

[0042] Figure 8 Received and transmitted ramp waveforms with sawtooth chirp modulation are shown in accordance with aspects of the present disclosure.

[0043] Fig. 9 An equalization process according to aspects of the present disclosure is shown.

[0044] Fig.10 A resampling process according to aspects of the present disclosure is shown.

[0045] Fig.11 Examples of receiver processing according to aspects of the present disclosure are shown.

[0046] Fig.12 is an example showing an example of the effect on an interfering radar signal at a mismatched receiver.

[0047] Fig.13 A flow chart illustrating a method for selecting waveform parameters and processing a reflected waveform according to aspects of the present disclosure is shown.

[0048] Fig.14 Certain components that may be included within a base station according to aspects of the present disclosure are shown.

[0049] Fig.15 Certain components that may be included within a wireless communication device in accordance with aspects of the present disclosure are shown.

[0050] Fig.16 A flow chart illustrating a method for selecting waveform parameters and processing a reflected waveform according to aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0051] In some wireless communication systems such as 5th generation (5G) new radio (NR) systems, the transmit waveform may include cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) and discrete Fourier transform spread (DFT-S) OFDM. 5G allows switching between CP-OFDM and DFT-S-OFDM on the uplink (UL) to obtain the multiple-input multiple-output (MIMO) spatial multiplexing advantages of CP-OFDM and the link budget advantages of DFT-S-OFDM. With long-term evolution (LTE), orthogonal frequency division multiple access (OFDMA) communication signals may be used for downlink (DL) communications, while single-carrier frequency division multiple access (SC-FDMA) communication signals may be used for LTE UL communications. The DFT-s-OFDMA scheme spreads a set of data symbols (i.e., a sequence of data symbols) over a frequency domain different from the OFDMA scheme. Moreover, the DFT-s-OFDMA scheme may greatly reduce the peak-to-average power ratio (PAPR) of the transmit signal compared to the OFDMA scheme. The DFT-s-OFDMA scheme may also be called an SC-FDMA scheme.

[0052] Scalable OFDM multi-tone numerology is another feature of 5G. Previous versions of LTE supported a basically fixed OFDM numerology with a 15 kilohertz (kHz) spacing between OFDM tones (commonly referred to as subcarriers) and a carrier bandwidth of up to 20 megahertz (MHz). Scalable OFDM numerology has been introduced in 5G to support a variety of spectrum bands / types and deployment models. For example, 5G NR is able to operate in millimeter wave (mmW) bands, which have wider channel widths (e.g., hundreds of megahertz) than the bands used in LTE. Moreover, the OFDM subcarrier spacing can be scaled with the channel width, so the fast Fourier transform (FFT) size can also be scaled so that the processing complexity is not unnecessarily increased for wider bandwidths. In this application, numerology can refer to different values ​​that can be adopted by different features of the communication system (e.g., subcarrier spacing, cyclic prefix (CP), symbol length, FFT size, transmit time interval (TTI), etc.).

[0053] Also in 5G NR, cellular technology has been extended to unlicensed spectrum (such as standalone access and licensed assisted access (LAA)). In addition, unlicensed spectrum can occupy frequencies up to 60 gigahertz (GHz), also known as mmW. The use of unlicensed frequency bands provides increased capacity for communications in the system.

[0054] The first member of this technology family is called LTE Unlicensed (LTE-U). By aggregating LTE in the unlicensed spectrum with an "anchor" channel in the licensed spectrum, customers can be provided with faster download speeds. In addition, LTE-U can fairly share the unlicensed spectrum with Wi-Fi. This is an advantage because LTE-U is expected to coexist with Wi-Fi in the 5GHz unlicensed band where Wi-Fi devices are widely used. However, LTE-U networks may cause radio frequency (RF) interference to existing co-channel Wi-Fi devices. Selecting a preferred operating channel and minimizing interference to nearby Wi-Fi networks may be the goal of LTE-U devices. However, if all available channels are occupied by Wi-Fi devices, LTE-U single carrier (SC) devices can operate on the same channel as Wi-Fi. In order to coordinate spectrum access between LTE-U and Wi-Fi, the energy on the intended transmission band can be detected first. This energy detection (ED) mechanism notifies the device of ongoing transmissions by other nodes. Based on this ED information, the device decides whether it should transmit on the intended transmission band. Unless the interference level caused by the LTE-U transmission is above the ED threshold (e.g., negative 62 decibel-milliwatts (dBm) at 20 MHz), the Wi-Fi device may not exit the LTE-U transmission. Therefore, if there is no appropriate coexistence mechanism, the LTE-U transmission may cause considerable interference to the Wi-Fi network relative to the Wi-Fi transmission.

[0055] LAA is another member of the unlicensed technology family. Like LTE-U, it also uses anchor channels in the licensed spectrum. However, it also adds "listen before talk" (LBT) operation to LTE functionality.

[0056] The gating interval can be used to gain access to a channel of a shared spectrum. The gating interval can determine the application of a contention-based protocol (such as the LBT protocol). The gating interval can indicate when to perform a clear channel assessment (CCA). The CCA determines whether a channel of a shared unlicensed spectrum is available or in use. If the channel is "clear" for use, that is, it is available, the gating interval can allow the transmitting device to use the channel. Access to the channel is usually granted within a predefined transmission interval. Therefore, for unlicensed spectrum, a "listen before talking" process is performed before sending a message. If the channel is not clear for use, the device will not transmit on the channel.

[0057] Another member of this unlicensed technology family is LTE Wireless LAN (WLAN) Aggregation (LWA), which can use both LTE and Wi-Fi. LWA can split a single data stream into two data streams, taking into account the two channel conditions, allowing both LTE and Wi-Fi channels to be used for applications. LTE signals can seamlessly use WLAN connections to increase capacity instead of competing with Wi-Fi.

[0058] The final member of this unlicensed technology family is MulteFire. MulteFire opens up new opportunities by operating fourth generation (4G) LTE technology only in unlicensed spectrum (e.g., global 5GHz). Unlike LTE-U and LAA, MulteFire can support entities without access to licensed spectrum. Therefore, it operates independently in unlicensed spectrum (e.g., without the need for any anchor channels in the licensed spectrum). Therefore, MulteFire is different from LTE-U, LAA, and LWA because LTE-U, LAA, and LWA aggregate unlicensed spectrum with anchors in licensed spectrum. MulteFire allows for Wi-Fi-like deployments without relying on licensed spectrum as an anchor service. A MulteFire network may include access points (APs) and / or base stations that communicate in unlicensed RF spectrum bands (e.g., without a licensed anchor carrier).

[0059] Demodulation Reference Signal (DMRS) Measurement Timing Configuration (DMTC) is a technique that allows MulteFire to transmit with minimal or reduced interference to other unlicensed technologies, including Wi-Fi. In addition, the periodicity of discovery signals in MulteFire can be very sparse. This allows MulteFire to occasionally access the channel, send discovery and control signals, and then vacate the channel. Since the unlicensed spectrum is shared with other radios of similar or dissimilar wireless technologies, a so-called LBT method can be applied to channel sensing. LBT may include sensing the medium for a predetermined minimum amount of time and exiting if the channel is busy. Therefore, the initial random access (RA) process for standalone LTE-U may include a minimum number of transmissions with low latency, so that the number of LBT operations can be minimized or reduced and the RA process can be completed relatively quickly.

[0060] Using the DMTC window, the MulteFire algorithm can search and decode reference signals in the unlicensed band from neighboring base stations to identify the base station serving the user. As the caller moves past a base station, their user equipment (UE) can send measurement reports to the base station, triggering the handover process and transferring the caller (and all its content and information) to the next base station.

[0061] Since LTE traditionally operates in licensed spectrum and Wi-Fi operates in unlicensed bands, coexistence with Wi-Fi or other unlicensed technologies was not considered when LTE was designed. In moving to the unlicensed world, the LTE waveform was modified and algorithms were added to perform LBT. This supports the ability to share channels with unlicensed incumbents including Wi-Fi by not immediately acquiring the channel and transmitting. This example supports LBT as well as the detection and transmission of Wi-Fi Channel Usage Beacon Signals (WCUBS) to ensure coexistence with Wi-Fi neighbors.

[0062] MulteFire is designed to "hear" transmissions from neighboring Wi-Fi base stations. When there are no other neighboring Wi-Fi transmissions on the same channel (e.g., within a threshold range), MulteFire can listen first and autonomously decide to transmit. This technique ensures coexistence between MulteFire and Wi-Fi transmissions.

[0063] Various aspects of the present disclosure are first described in the context of a wireless communication system. Then, various aspects of the present disclosure are illustrated and described through apparatus diagrams, system diagrams, and processes related to using a lateral communication channel to exchange radar information to improve multi-radar coexistence.

[0064] Figure 1 An example wireless network 100 (e.g., a NR network, a 5G network, or other type of wireless communication network or system) is shown in accordance with aspects of the present disclosure.

[0065] like Figure 1 As shown, the wireless network 100 may include multiple base stations 110 and other network entities. The base station 110 may be a station that communicates with the UE 120. Each base station 110 may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to the coverage area of ​​the Node B and / or the Node B subsystem serving the coverage area, depending on the context in which the term "cell" is used. In the NR system, the term "cell" and the evolved Node B (eNB), Node B, 5G narrowband (NB), AP, NR base station, NR base station, 5G radio Node B (gNB) or transmission reception point (TRP) may be interchangeable. In some aspects, the cell may not necessarily be fixed, and the geographical area of ​​the cell may move according to the location of the mobile base station 110. In some aspects, the base station 110 may use any suitable transmission network, interconnected with each other and / or with one or more other base stations 110 or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces (e.g., direct physical connection, virtual network, etc.).

[0066] Typically, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific radio access technology (RAT) and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, frequency channel, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0067] The base station 110 may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access to UEs 120 with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access to UEs 120 with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access to UEs 120 associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in the home, etc.). A base station 110 for a macro cell may be referred to as a macro base station 110. A base station for a pico cell may be referred to as a pico base station. A base station for a femto cell may be referred to as a femto base station or a home base station. In Figure 1 In the example shown, base stations 110a, 110b, and 110c may be macro base stations for macro cells 102a, 102b, and 102c, respectively. Base station 110x may be a pico base station for pico cell 102x. Base stations 110y and 110z may be femto base stations for femto cells 102y and 102z, respectively. A base station may support one or more (e.g., three) cells.

[0068] The wireless network 100 may also include a relay station. A relay station receives transmissions of data and / or other information from an upstream station (e.g., a base station 110 or a UE 120) and transmits transmissions of data and / or other information to a downstream station (e.g., a UE 120 or a base station 110). A relay station may also be a UE 120 that relays transmissions for other UEs 120. Figure 1 In the example shown, a relay station 110r may communicate with a base station 110a and a UE 120r to facilitate communications between the base station 110a and the UE 120r. A relay station may also be referred to as a relay base station, a relay, or the like.

[0069] The wireless network 100 may be a heterogeneous network that includes different types of base stations 110, such as macro base stations, pico base stations, femto base stations, relays, etc. These different types of base stations may have different transmit power levels, different coverage areas, and may have different effects on interference in the wireless network 100. For example, a macro base station may have a higher transmit power level (e.g., 20 watts), while a pico base station or femto base station or relay may have a lower transmit power level (e.g., 1 watt).

[0070] Wireless network 100 may support synchronous or asynchronous operation. For synchronous operation, base stations 110 may have similar frame timing, and transmissions from different base stations 110 may be approximately aligned in time. For asynchronous operation, base stations 110 may have different frame timing, and transmissions from different base stations 110 may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

[0071] A network controller 130 may couple to a set of base stations 110 and provide coordination and control for these base stations 110. The network controller 130 may communicate with the base stations 110 via a backhaul. The base stations 110 may also communicate with each other, eg, directly or indirectly, via a wireless or wired backhaul.

[0072] UEs 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless network 100, and each UE may be fixed or mobile. UE 120 may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a customer premises equipment (CPE), a cellular phone, a smart phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or medical equipment, a healthcare device, a biometric sensor / device, a wearable device (e.g., a smart watch, smart clothing, smart glasses, virtual reality goggles, a smart wristband, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite broadcast, etc.), vehicle components or sensors, smart meters / sensors, robots, drones, industrial manufacturing equipment, positioning equipment (e.g., Global Positioning System (GPS), Beidou, ground, etc.), or any other suitable device configured to communicate via a wireless or wired medium. Some UEs 120 may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices, which may include remote devices that can communicate with a base station 110, another remote device, or some other entity. MTC may refer to communication involving at least one remote device on at least one end of the communication, and may include a form of data communication involving one or more entities that do not require human interaction. MTC The UE may include, for example, a UE 120 capable of MTC communications with an MTC server and / or other MTC devices via a public land mobile network (PLMN). MTC and enhanced MTC (eMTC) UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, cameras, location tags, etc., which can communicate with a base station 110, another device (e.g., a remote device), or some other entity. A wireless node may provide, for example, a connection to a network or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. MTC UEs and other UEs 120 may be implemented as Internet of Things (IoT) devices, such as narrowband IoT (NB-IoT) devices. In NB IoT, when the UE 120 decodes data in diffuse coverage, the UL and DL have higher periodicity and repetition interval values.

[0073] exist Figure 1 , a solid line with double arrows indicates desired transmissions between a UE 120 and a serving base station, which is a base station 110 designated to serve the UE 120 on the DL and / or UL. A dashed line with double arrows indicates interfering transmissions between the UE 120 and the base station 110.

[0074] Some wireless networks, such as LTE, use OFDM on the DL and single carrier frequency division multiplexing (SC-FDM) on the UL. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier can be modulated with data. Typically, modulation symbols are sent in the frequency domain using OFDM and in the time domain using SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers K can depend on the system bandwidth. For example, the spacing between subcarriers can be 15kHz, and the minimum resource allocation (called a "resource block") can be 12 subcarriers (or 180kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20MHz, the nominal FFT size can be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth can also be divided into subbands. For example, a subband may cover 1.08 MHz (eg, six resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

[0075] Although various aspects of the examples described herein may be associated with LTE technology, various aspects of the present disclosure may be applicable to other wireless communication systems, such as NR or other wireless communication systems. NR can utilize OFDM with CP on UL and DL, and can include support for half-duplex operation using time division duplex (TDD). A single component carrier bandwidth of 100 MHz can be supported. NR resource blocks can span 12 subcarriers with a bandwidth of 75 kHz subcarriers in a duration of 0.1 milliseconds (ms). Each radio frame can consist of 50 subframes with a length of 10 ms. Therefore, each subframe can have a length of 0.2 ms. Each subframe can indicate a link direction (e.g., DL or UL) for data transmission, and the link direction for each subframe can be switched dynamically. Each subframe can include DL / UL data and DL / UL control data. It can be about Fig. 6A , Figure 6B , Fig. 7A and Figure 7BUL and DL subframes (e.g., for NR) are described in more detail. Beamforming may be supported, and the beam direction may be dynamically configured. MIMO transmission with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas, with multi-layer DL transmission of up to 8 streams and up to 2 streams per UE 120. Multi-layer transmission with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells. Alternatively, NR may support different air interfaces in addition to OFDM-based interfaces. The NR network may include entities such as a central unit (CU) and / or a distributed unit (DU).

[0076] In some aspects, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station 110) allocates resources for communication between some or all devices and equipment within its service area or cell. In the present disclosure, as further discussed herein, a scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, subordinate entities utilize resources allocated by the scheduling entity. The base station 110 is not the only entity that may be used as a scheduling entity. That is, in some aspects, a UE 120 may be used as a scheduling entity, scheduling resources for one or more subordinate entities (e.g., one or more other UEs 120). In this aspect, a first UE 120 acts as a scheduling entity, and other UEs 120 utilize resources scheduled by the first UE 120 for wireless communication. UE 120 may be used as a scheduling entity in a peer-to-peer (P2P) network and / or a mesh network. In a mesh network example, in addition to communicating with a scheduling entity, UE 120 may also optionally communicate directly with each other.

[0077] Thus, in a wireless communication network having scheduled access to time-frequency resources and having a cellular configuration, a P2P configuration, and a mesh configuration, a scheduling entity and one or more slave entities may communicate using the scheduled resources.

[0078] As described herein, a radio access network (RAN) may include a CU and one or more DUs. A NR base station (e.g., an eNB, a 5G Node B, a Node B, a TRP, an AP, or a gNB) may correspond to one or more base stations 110. An NR cell may be configured as an access cell (ACell) or a data-only cell (DCell). For example, a RAN (e.g., a CU or a DU) may configure a cell. A DCell may be a cell used for carrier aggregation or dual connectivity, but not for initial access, cell selection / reselection, or switching. In some cases, a DCell may not send a synchronization signal (SS), while in other cases, a DCell may send an SS. The NR base station may send a DL signal indicating a cell type to the UE 120. Based on the cell type indication, the UE 120 may communicate with the NR base station. For example, the UE 120 may determine, based on the indicated cell type, that the NR base station is to be considered for cell selection, access, switching, and / or measurement.

[0079] In some cases, UE 120 may be an example of a vehicle operating within wireless network 100. In these cases, UE 120 may detect other UEs 120 and communicate directly with the other UEs 120 (e.g., with no or minimal communication with base station 110). In some cases, UE 120 may transmit radar waveforms to detect nearby UEs 120. However, if these other UEs 120 also transmit radar waveforms to detect target devices, multiple radar sources may cause interference and poor detection performance. In some aspects, each UE 120 may select waveform parameters (e.g., chirp slope and / or frequency offset) used by the UE 120 to reduce interference caused by other radar waveforms.

[0080] Figure 2 2 shows an example logical architecture of a distributed RAN 200 according to various aspects of the present disclosure. The distributed RAN 200 may be Figure 1 206. The 5G access node 206 may include an access node controller (ANC) 202. The ANC may be a CU of a distributed RAN 200. The backhaul interface to the next generation core network (NG-CN) 204 may terminate at the ANC 202. The backhaul interface to the adjacent next generation access node (NG-AN) 210 may terminate at the ANC 202. The ANC 202 may include one or more TRPs 208, which may also be referred to as base stations, NR base stations, Node Bs, 5G NBs, APs, eNBs, gNBs, or some other terms. As described herein, TRPs 208 may be used interchangeably with "cells".

[0081] The TRP 208 may be an example of a DU. The TRP 208 may be connected to one ANC (e.g., ANC 202) or more than one ANC. For example, for RAN sharing, Radio as a Service (RaaS), and service-specific ANC deployments, the TRP 208 may be connected to more than one ANC 202. The TRP 208 may include one or more antenna ports. The TRP 208 may be configured to serve traffic to the UE individually (e.g., in dynamic selection) or collectively (e.g., in joint transmission).

[0082] The local architecture can be used to illustrate the fronthaul definition. The architecture can be defined so that it can support fronthaul solutions across different deployment types. For example, the architecture can be based on the sending network capabilities (e.g., bandwidth, latency, and / or jitter).

[0083] The architecture may share features and / or components with LTE. According to various aspects, the NG-AN 210 may support dual connectivity with NR. The NG-AN 210 may share a common fronthaul for LTE and NR.

[0084] This structure may enable collaboration between TRPs 208. For example, collaboration may be provisioned within a TRP 208 and / or across TRPs 208 via ANC 202. According to various aspects, an inter-TRP interface may not be required / existent.

[0085] According to various aspects, there may be a dynamic configuration of split logic functions within the architecture. The radio resource control (RRC) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, the medium access control (MAC) layer, and the physical (PHY) layer may be adaptively placed at the DU or CU (e.g., TRP 208 or ANC 202, respectively). According to certain aspects, the base station may include a CU (e.g., ANC 202) and / or one or more distributed units (e.g., one or more TRP208). In some cases, the distributed RAN 200 may support a system that includes multi-radar coexistence. In these cases, the distributed RAN 200 may support the selection of radar waveform parameters to allow devices to distinguish device-specific radar waveforms, thereby allowing improved multi-radar coexistence between devices.

[0086] Figure 3 An example physical architecture of a distributed RAN 300 according to aspects of the present disclosure is shown. A centralized core network unit (C-CU) 302 may host core network functions. The C-CU 302 may be centrally deployed. To handle peak capacity, the C-CU 302 functions may be offloaded (e.g., to Advanced Wireless Services (AWS)).

[0087] A centralized RAN unit (C-RU) 304 may host one or more ANC functions. Optionally, the C-RU 304 may host core network functions locally. The C-RU 304 may have a distributed deployment. The C-RU 304 may be closer to the network edge.

[0088] The DU 306 may host one or more TRPs (e.g., edge nodes (ENs), edge units (EUs), radio heads (RHs), smart radio heads (SRHs), etc.). The DU 306 may be located at the edge of the network with RF capabilities. In some cases, the distributed RAN 300 may support devices that can select radar waveform parameters to improve multi-radar coexistence.

[0089] Figure 4 1 shows a base station 110 and a UE 120 (eg, as shown in FIG. 1 ) in a wireless communication system 400 according to various aspects of the present disclosure. Figure 1 As described herein, base station 110 may include one or more TRPs. One or more components of base station 110 and UE 120 may be used to practice aspects of the present disclosure. For example, antenna 452, processors 466, 458, 464, and / or controller / processor 480 of UE 120, and / or antenna 434, processors 430, 420, 438, and / or controller / processor 440 of base station 110 may be used to perform the operations described herein.

[0090] Figure 4 A block diagram showing a design of a base station 110 and a UE 120 is shown, which may be a reference Figure 1 For a restricted association scenario, the base station 110 may be one of the base stations and one of the UEs described. Figure 1 1 and 120. The macro base station 110c in FIG. 1 may be a macro base station 110c, and the UE 120 may be a UE 120y. The base station 110 may also be some other type of base station. The base station 110 may be equipped with antennas 434a to 434t, and the UE 120 may be equipped with antennas 452a to 452r.

[0091] At the base station 110, the transmit processor 420 may receive data from the data source 412 and control information from the controller / processor 440. The control information may be used for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid automatic repeat request (ARQ) indicator channel (PHICH), a physical downlink control channel (PDCCH), etc. The data may be used for a physical downlink shared channel (PDSCH), etc. The transmit processor 420 may process (e.g., encode and symbol map) the data and the control information to obtain data symbols and control symbols, respectively. The processor 420 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a cell-specific reference signal, etc. The transmit (TX) MIMO processor 430 may perform spatial processing (e.g., precoding) on ​​the data symbols, control symbols, and / or reference symbols (if applicable), and may provide output symbol streams to modulators (MODs) 432a to 432t. For example, the TX MIMO processor 430 may perform certain aspects described herein for reference signal (RS) multiplexing. Each modulator 432 may process a corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 432 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a DL signal. The DL signals from modulators 432a through 432t may be transmitted via antennas 434a through 434t, respectively.

[0092] At the UE 120, antennas 452a to 452r may receive DL signals from the base station 110 and may provide received signals to demodulators 454a to 454r, respectively. Each demodulator 454 may condition (e.g., filter, amplify, downconvert, and digitize) a corresponding received signal to obtain input samples. Each demodulator 454 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. The MIMO detector 456 may obtain received symbols from all demodulators 454a to 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. For example, the MIMO detector 456 may provide detected RSs sent using the techniques described herein. The receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120 to the data sink 460, and provide decoded control information to the controller / processor 480. According to one or more scenarios, coordinated multi-point (CoMP) aspects may include providing antennas and certain Tx / receive (Rx) functions so that they reside in the DU. For example, some Tx / Rx processing may be done in the CU, while other processing may be done on the DU. According to one or more aspects as shown, the base station MOD / DEMOD 432 may be in the DU.

[0093] On the UL, at the UE 120, a transmit processor 464 may receive and process data from a data source 462 (e.g., for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 480 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 464 may also generate reference symbols for a reference signal. The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466 (if applicable), further processed by demodulators 454a through 454r (e.g., for SC-FDM, etc.), and transmitted to the base station 110. At the base station 110, the UL signal from the UE 120 may be received by the antenna 434, processed by the modulator 432, detected by the MIMO detector 436 (if applicable), and further processed by the receive processor 438 to obtain decoded data and control information sent by the UE 120. The receive processor 438 may provide the decoded data to a data sink 439 and the decoded control information to the controller / processor 440.

[0094] Controllers / processors 440 and 480 may direct the operation at base station 110 and UE 120, respectively. Processor 440 and / or other processors and modules at base station 110 may perform or direct processes for the techniques described herein. Processor 480 and / or other processors and modules at UE 120 may also perform or direct processes for the techniques described herein. Memories 442 and 482 may store data and program codes for base station 110 and UE 120, respectively. Scheduler 444 may schedule UEs for data transmission on the DL and / or UL.

[0095] although Figure 4 Communication between a base station 110 and a UE 120 is shown, but in some systems, UEs 120 can detect each other and send information directly to each other (e.g., via a side communication channel). UEs 120 can communicate directly with other UEs 120 (e.g., without communication through or relayed by base station 110). In some cases, UEs 120 can send radar waveforms (e.g., using antenna 452) to detect nearby UEs 120 to facilitate communication or avoid conflicts. In order to improve multi-radar coexistence between UEs 120, each UE 120 can select radar waveform parameters to reduce interference. For example, UE 120 can send a waveform by sending multiple linear frequency modulation pulses of the waveform. A linear frequency modulation pulse can be a waveform whose frequency changes (e.g., increases or decreases). Each linear frequency modulation pulse of the waveform can have a time period, and the rate of frequency change during the time period can be referred to as a linear frequency modulation pulse slope. The linear frequency modulation pulse can also be associated with a frequency offset. Therefore, the linear frequency modulation pulse slope and the frequency offset can be waveform parameters that can specify the linear frequency modulation pulse characteristics.

[0096] In some cases, UE 120 may change waveform parameters for at least a subset of the chirp pulses of the transmitted signal to reduce interference with signals transmitted by nearby UEs 120 or other devices. Changing the waveform parameters in this way may improve the reliability of the target detection process performed by UE 120.

[0097] Figure 5A An example of a DL-centric subframe 500A according to aspects of the present disclosure is shown. The DL-centric subframe 500A may include a control portion 502A. The control portion 502A may be present in an initial or beginning portion of the DL-centric subframe 500A. The control portion 502A may include various scheduling information and / or control information corresponding to various portions of the DL-centric subframe 500A. In some configurations, the control portion 502A may be a PDCCH, such as Figure 5A shown.

[0098] The DL-centric subframe 500A may also include a DL data portion 504A. The DL data portion 504A may sometimes be referred to as a payload of the DL-centric subframe 500A. The DL data portion 504A may include communication resources for communicating DL data from a scheduling entity 202 (e.g., an eNB, a base station, a Node B, a 5G NB, a TRP, a gNB, etc.) to a subordinate entity (e.g., a UE 120). In some configurations, the DL data portion 504A may be a PDSCH.

[0099] The DL-centric subframe 500A may also include a common UL portion 506A. The common UL portion 506A may sometimes be referred to as a UL burst, a common UL burst, and / or various other suitable terms. The common UL portion 506A may include feedback information corresponding to various other parts of the DL-centric subframe 500A. For example, the common UL portion 506 may include feedback information corresponding to the control portion 502A. Non-limiting examples of feedback information may include an acknowledgment (ACK) signal, a negative acknowledgment (NACK) signal, a hybrid automatic repeat request (HARQ) indicator, and / or various other types of information. The common UL portion 506A may include additional information or alternative information, such as information related to a random access channel (RACH) process, a scheduling request (SR), a sounding reference signal (SRS), and various other suitable types of information.

[0100] like Figure 5A As shown, the end of the DL data portion 504A may be separated in time from the beginning of the common UL portion 506A. This time separation may sometimes be referred to as a gap, a guard period (GP), a guard interval, and / or various other suitable terms. This separation provides time for switching from DL communications (e.g., receiving operations by a subordinate entity such as UE 120) to UL communications (e.g., transmissions by a subordinate entity such as UE 120). However, it will be appreciated by those of ordinary skill in the art that the foregoing is merely an example of a DL-centric subframe 500A, and that alternative structures with similar features may exist without necessarily departing from the aspects described herein.

[0101] Figure 5B An example of a UL-centric subframe 500B according to aspects of the present disclosure is shown. The UL-centric subframe 500B may include a control portion 502B. The control portion 502B may be present in an initial or beginning portion of the UL-centric subframe 500B. Figure 5B The control portion 502B in the embodiment may be similar to that of the reference Figure 5AThe control portion 502A described above. The UL-centric subframe 500B may also include a UL data portion 504B. The UL data portion 504B may sometimes be referred to as the payload of the UL-centric subframe 500B. The UL portion may refer to communication resources used to communicate UL data from a subordinate entity (e.g., UE 120) to a scheduling entity 202 (e.g., base station 110). In some configurations, the control portion 502B may be a PUSCH. Figure 5B As shown, the end of the control portion 502B may be separated in time from the beginning of the UL data portion 504B. This time separation may sometimes be referred to as a gap, a GP, a guard interval, and / or various other suitable terms. This separation provides time for switching from DL communication (e.g., reception operation of the scheduling entity 202) to UL communication (e.g., transmission of the scheduling entity 202).

[0102] The UL-centric subframe 500B may also include a common UL portion 506B. Figure 5B The common UL portion 506B in the embodiment may be similar to that of the reference Figure 5A The common UL portion 506A described above. The common UL portion 506B may additionally or alternatively include information related to a channel quality indicator (CQI), SRS, and various other types of information. It will be appreciated by those of ordinary skill in the art that the foregoing is merely one aspect of the UL-centric subframe 500B, and that alternative structures having similar features may exist without necessarily departing from the aspects described herein.

[0103] As described herein, a UL-centered subframe 500B may be used to send UL data from one or more mobile stations to a base station, and a DL-centered subframe may be used to send DL data from a base station to one or more mobile stations. In one aspect, a frame may include a UL-centered subframe 500B and a DL-centered subframe 500A. In this aspect, the ratio of the UL-centered subframe 500B to the DL-centered subframe 500A in the frame may be dynamically adjusted based on the amount of UL data and the amount of DL data to be sent. For example, if there is more UL data, the ratio of the UL-centered subframe 500B to the DL-centered subframe 500A may be increased. Conversely, if there is more DL data, the ratio of the UL-centered subframe 500A to the DL-centered subframe 500B may be reduced.

[0104] Multiple radar sources can cause severe interference. Some radar waveforms, such as frequency modulated continuous wave (FMCW) radar, may not natively support multi-access and therefore may not be distinguishable when transmitted from various sources (e.g., vehicles). Therefore, with multiple radar sources, it may be difficult to determine whether a reflection is from a detected target, or whether the reflection is interference from another radar source (e.g., another vehicle).

[0105] Based on the reflections of the FMCW signal, the automotive radar can determine the distance to the target and the relative speed between the target and the source vehicle. For example, the FMCW automotive radar can obtain range and speed information from the beat frequency, which is composed of propagation delay and Doppler frequency. Doppler frequency shift Can be introduced by a target moving at speed v with radar wavelength λ. In a multi-radar coexistence scenario, transmissions from other radar sources (e.g., vehicles) can appear as ghost targets, which can be particularly troublesome because ghost targets can appear in the same angular direction as the expected reflected signal from that object (e.g., vehicle), and it may not be easy to identify them as ghost or normal (expected) targets.

[0106] Additionally, the direct signal from the radar source can be significantly stronger than the reflected signal from the target and can cause problems for the receiver to detect weak reflected signals in the presence of strong interfering transmissions from other radar sources. In some cases, the reflected signal can be as strong as about 1 / R 4 Attenuation, where R is the distance from the target to the vehicle transmitting the FMCW waveform, and source signals from other vehicles can be reduced by 1 / R 2 attenuation.

[0107] Fig. 6A An example wireless communication system 600A according to aspects of the present disclosure is shown. The wireless communication system 600A may include a vehicle 620 that transmits a radar. The vehicle 620 may be as described with reference to Figure 1 5 . Vehicle 620 may encounter other UEs 120 (e.g., vehicles 625 and 630), which may be moving toward or away from vehicle 620. Both vehicles 625 and 630 reflect back desired signals 610 and 615, respectively (e.g., based on radar transmitted by vehicle 620). Vehicle 630, which is closest to vehicle 620, may also transmit radar 605 or other types of signals, which may become interference to vehicle 620. If vehicle 630 transmits a radar waveform, vehicle 620 may not be able to distinguish between interference caused by radar waveform 605 and reflected signals indicating nearby targets (e.g., nearby UEs 120, vehicles, structures, interference sources, etc.).

[0108] Figure 6BAn example graph 600B is shown according to various aspects of the present disclosure, which shows the received power of the direct signal and the reflected signal at the distance. Graph 600B can illustrate the problem of interference from the direct signal, because the interference caused by the direct transmission 617 is much stronger than the reflected signal 622 from the target. Axis 607 can represent the range of received power values ​​of the signal (in dBm), and axis 612 can represent the distance from the source (e.g., the vehicle 620 transmitting the radar) to the target (e.g., the vehicle 630). At half the distance from the actual target (e.g., plus the time offset), the interference can appear as a ghost target and the power is higher. For the reflected signal from the target, due to the near-far effect, the desired (i.e., reflected) signal may have a relatively low signal-to-interference ratio (SIR), the direct transmission 617 is received with a much stronger power than the reflected (desired) signal 622 from the target, or both. That is, the interference can have a relatively high power compared to the desired signal reflected from the target.

[0109] Graph 600B shows the received signal power from the device-based reflected (desired) path (e.g., due to the radar transmission of the first source device) and the direct (interfering) signal from the second source device, assuming the transmit power at both radar sources is the same. The reflected signal can be expressed as approximately 1 / R 4 where R is the distance from the vehicle 630 reflecting the radar, and the direct interference signal can be attenuated by about 1 / R 2 The coefficient of attenuation is , where R is the distance from the vehicle 630 that sends the direct interference radar signal. Therefore, based on Fig. 6A and Figure 6B In the example shown, the reflected signal 615 from the desired target 625 at a far distance 635 (e.g., one hundred fifty (150) meters from the source vehicle 620) may be weaker than the direct interfering signal from the nearby source 630 at a far distance 640 (e.g., 10 meters) and may create a challenging environment for target detection. Note that in some cases, some spatial suppression may mitigate the near-far effect and depends on the geometry (e.g., location of the desired radar source, target, interfering radar source, etc.) and spatial response of the radar receiver antenna. However, such spatial suppression may not always occur. For example, in Fig. 6A In the case where the three cars in the image are in (or nearly in) a straight line so that there is no (or small) angular difference between the two radio paths (the desired radar to the target and the desired radar to the jammer radar), spatial suppression may not always be included.

[0110] The present methods, apparatus, and non-transitory processor-readable storage media may enable multi-channel coexistence from multiple radar sources using phase-coded waveforms (e.g., FMCW waveforms). In some cases, including for vehicles, FMCW is the most commonly used waveform. However, the operations described herein may also be applied to other radar waveforms. For FMCW, the frequency of the waveform varies linearly over time as a sawtooth or triangular function. The vehicle 620 transmitting the radar waveform may receive and process reflected signals from (one or more) targets and detect the range and Doppler of each target based on the difference between the received frequency and the transmitted frequency. In some cases, the transmitted radar waveform may include a frequency modulated ramp, which may also be referred to as a linear frequency modulation pulse (chirp), and each may have a specific linear frequency modulation pulse duration. In FMCW, the modulated signal may be periodically varied over a fixed time period (e.g., a scan time T). c ) linearly changes the instantaneous frequency of the chirp (e.g., from 0 to B Hz).

[0111] Fig. 7A and Figure 7B 1 and 10 are frequency-time diagrams 700A and 700B showing FMCW transmitted using chirp pulses associated with various waveform parameters according to aspects of the present disclosure. In the frequency-time diagrams 700A and 700B, B may represent the frequency range 705 or 707 of the FMCW, T c The duration of the chirp 715 or 717 may be represented (e.g., in the time domain 710 or 712). The frequency of the wave sweeps across the bandwidth from zero (0) to B (where 0 and B show the frequency range, and the actual frequency value may be any value within the bandwidth). The modulated signal x(t) (e.g., as depicted in the frequency-time graphs 700A and 700B) may be offset from a frequency f 0 Start ramping its frequency over bandwidth B. The transmitted signal x(t) may hit the target and reflect back to the receiving antenna, where the reflection of the transmitted signal x(t) is collected or received. The frequency difference Δf between the transmitted signal and the received signal may increase with the delay in receiving the reflected signal. The distance of the target from the radar may be referred to as the range, and the delay τ may be linearly proportional to the range between the target and the transmitting source and may be equal to the round-trip time. The echo (e.g., the reflected signal) from the target may be mixed with the transmitted signal and down-converted to produce a beat frequency signal, which after demodulation may be linearly proportional to the range between the target and the signal source.

[0112] Figure 8An FMCW system 800 with received and transmitted ramp waveforms with sawtooth chirp modulation is shown in accordance with aspects of the present disclosure. Axis 805 may represent frequency and axis 810 may represent time. Time interval 815 may represent delay τ. Frequency interval 820 may represent the frequency difference Δf between a transmitted signal 830 and a received signal 835. The transmitted signal 830 includes a linear frequency modulation pulse with a duration T c The received signal 835 includes a plurality of linear frequency modulation pulses having a duration T c The frequency interval 825 may be a frequency range B of the linear frequency modulation pulses.

[0113] FMCW transmit waveform x(t) Fig. 7A and Figure 7B is shown in and can be described by the following equation:

[0114] x(t)=exp(-j2πf c t)exp(-jπ(βt+f 0 )t), (1)

[0115] where f c is the carrier frequency, β is the slope, f 0 is the frequency offset.

[0116] In some cases (e.g., as shown), for radar waveforms, the chirp duration T c can remain the same, and the frequency of the wave can sweep through the frequency range B any number of times during the chirp duration. In other cases, the chirp duration T c may correspond to a single frequency sweep through the frequency range B, and therefore the chirp duration T c For a chirp set, the slope β can be changed depending on the slope. For a "fast" chirp, T c duration is short, while for a "slow" chirp, T c In some cases, UE 120 (eg, a vehicle) may select a waveform parameter set for transmission of a radar waveform and may vary the waveform parameter set for two or more chirps to produce the selected waveform parameters corresponding to frequency-time diagram 700B.

[0117] The system can be configured to determine the degree to which the linear frequency modulation pulse parameters are changed. As described above, the linear frequency modulation pulse T can be completely defined. c Two parameters of the waveform used may be the slope β and the frequency offset f 0 , where for a particular chirp, the slope can be defined as For example, an FMCW radar system can be designed to linearly sweep the frequency in the range of 1 GHz and 50 microseconds (us), resulting in a slope of β = 1 GHz / 50us and a frequency offset f 0 It can be set to any value between 0 and 1 GHz. The frequency offset f 0 It can correspond to the linear frequency modulation pulse duration T c The initial frequency value at the beginning. Fig. 7A In , the slope and frequency offset can be kept constant over multiple chirps. Fig. 7A As seen in FIG. 7 , multiple chirps may be sent back-to-back. That is, B705 may be the same for each chirp in the chirp set, and T c 715a, 715b and 715c may be identical for the chirp set, thereby producing a constant slope β for the chirp set. In addition, the frequency offset f 0 The chirp may be identical for each chirp in a set of chirps.

[0118] exist Figure 7B In , the UE may change the parameters from chirp to chirp (e.g., to change the radar waveform) instead of keeping the parameters constant. Figure 7B In the example, the ramp can start at a frequency offset f 0 (e.g., B / 2), ramp up to a frequency (e.g., B), return to 0 (i.e., zero offset) and ramp up to a frequency offset (e.g., B / 2). Typically, the radar frequency may be swept from 1 to 2 GHz. The chirp period may typically span between 10 and 200 microseconds.

[0119] The receiver can process multiple reflected radar waveforms. For example, the waveform of the processed received signal y(t) can be expressed as:

[0120]

[0121]

[0122] Where x(t) is the transmitted waveform, K φ =exp(-jπ(βt 0 -f 0 )t 0 ) is the phase term depending on the time delay of the target, exp(-j2π(v / λ)t) is the phase slope corresponding to Doppler, and exp(-j2πβt 0 t) is the phase slope corresponding to the time delay of the target, v is the velocity, c is the speed of light, λ is the wavelength of the transmitted waveform, and t 0is the time delay. In some cases, the processed received waveform y(t) can be expressed as the transmitted waveform x(t) multiplied by the phase term K φ (eg, depending on the slope and offset of the transmitted FMCW waveform and the time delay of the target) and two phase ramps (eg, each ramp corresponding to the time delay and Doppler of the target).

[0123] In some cases, when coherent detection is performed, the received signal may be compared (e.g., descrambled, multiplied) to the transmitted signal in the analog domain before being converted to the digital domain to be processed for target detection. For example, the received signal may be processed according to the following equation:

[0124]

[0125] In some cases, the descrambled received waveform is down-converted to the digital domain (for example, assuming a sampling rate of F s ), which results in a waveform that can be expressed as:

[0126]

[0127]

[0128] where r[m,n] represents the digital samples corresponding to the received waveform r(t) (after being descrambled by the transmitted waveform), K φ is the phase term that depends on the time delay of the target, v is the velocity, c is the speed of light, λ is the wavelength of the transmitted waveform, and t 0 is the time delay, m is the chirp index, and n is the index of the sample within the chirp. The approximation may involve decoupling the delay and Doppler phase slope by assuming that the phase slope variation within the chirp due to Doppler is negligible. Thus, the processed received signal r[m,n] may be given by the phase term K φ and two phase ramp terms (eg, one ramp each corresponding to the time delay and Doppler of the target).

[0129] The processed received signal r[m,n] can be obtained by the phase term K φ and two phase ramp terms (e.g., corresponding to the time delay and Doppler of the target) are expressed as follows:

[0130]

[0131] where m is the chirp index, β is the slope, λ is the wavelength, and T C is the period or duration of the linear frequency modulated pulse, F s is the sampling rate of the receiver, v is the speed, N cis the total number of chirps over which the parameter change is performed, n is the sample index, and t 0 is the time offset. In some cases, when the received signal is multiplied by the transmitted signal in the analog domain before downconversion, F s can be less than the chirp frequency range B. If the slope and offset of the transmitted waveform remain constant, and it is assumed that the time delay variation of the target due to mobility over the multiple chirps being processed is negligible, then the phase term K φ The receiver processing for target detection can then use the slopes of the two phase ramps to estimate the target's velocity v and time delay t 0 .

[0132] Figure 7C An example of signal processing 700C is shown that may be performed on multiple reflected chirps (e.g., chirps transmitted and received by the same UE 120). A first order discrete Fourier transform (DFT) 720, referred to as a fast-time DFT 720, may be used to process the received (e.g., reflected) waveforms. Figure 7C Three columns of bins generated by the fast time DFT 720 are shown for three corresponding chirp pulses 719-a, 719-b, and 719-c (e.g., received in the time dimension 714, where each chirp pulse has the same frequency range 709). Each column may represent a frequency bin having F s ×T C The time delay dimension 730 or time delay grid 730 of a grid size 725 of . As explained above, multiple chirps can be processed by applying a fast time DFT 720 to a single chirp, which can produce a target peak in an interval on the corresponding time delay grid 730, where the interval can represent a time offset. The fast time DFT 720 can be performed on each chirp 719. The peak can be represented by the cross-hatched interval in the time delay grid 730 (e.g., a 1-D diagram), where the vertical access represents time. Therefore, the target peak can represent a specific time offset or time offset range corresponding to a chirp 719 of the target.

[0133] In one example, the next processing step may include applying a slow time DFT 735 to all fast time DFT 720 results. For example, the slow time DFT 735 may be performed on two or more chirp pulses 719. In some aspects, the slow time DFT 735 may be applied to less than all fast time DFT 720 results. The slow time DFT 735 may be run on the fast time DFT to add the target peak in the time offset interval 730 to produce a Doppler peak in the Doppler time delay grid 740. Thus, for a given target, the fast time DFT 720 may produce a peak in the time delay dimension 730, where each interval represents a time offset, and the slow time DFT 735 may produce a peak in the Doppler time delay grid 740, where the interval may represent a time offset and a Doppler value. The cross-hatched interval may represent the location of the target peak.

[0134] The following equation may be used to calculate a two-dimensional (2D) DFT for time delay and Doppler detection (eg, corresponding to Doppler time delay grid 740), where time delay is a first dimension and Doppler is a second dimension:

[0135]

[0136] Where β is the slope, λ is the wavelength, T C is the period or duration of the chirp, F s is the sampling rate of the receiver, v is the speed, N c is the total number of chirps over which the parameter change is performed, k is the Doppler bin index, l is the time delay bin index, and δ is the Dirac-delta function. Thus, with a time delay t 0 and the target with a relative velocity v can result in the interval appearing in the Doppler dimension and the time delay dimension βT c t 0 The peak in.

[0137] In one example, a constant false alarm rate (CFAR) detector 750 may be used to detect which bins have peaks in the Doppler time delay grid 740. For example, for a peak detected by CFAR in the bin [k, l], where k indicates a Doppler peak and l indicates a time delay peak, the range peak and the Doppler peak may be calculated using the following formulas:

[0138]

[0139] Where T Cis the period or duration of the chirp, B is the frequency range, v is the velocity, k is the Doppler bin index, l is the time delay bin index, and c is the speed of light. If multiple antennas in the azimuth dimension are used, a three-dimensional (3D) graph can be generated, where the azimuth can be the third dimension. If multiple antennas in the elevation dimension are used, a four-dimensional (4D) graph can be generated, where the elevation can be the fourth dimension. The output from the CFAR detector 750 can be used to create another time delay Doppler grid 755, mark training cells 760, protection cells 765, and peaks 770 in the Doppler and time delay dimensions.

[0140] In some systems, interference can be randomized by changing the transmitted radar waveform from chirp to chirp. According to various aspects, if a parameter pattern is selected to change the chirp slope and frequency offset for each chirp, interference from other radars can be suppressed or shaped (e.g., offset). In some aspects, the FMCW waveform parameters may be changed at a frequency less than that of each chirp. For example, the FMCW waveform parameters may be changed for N c At least a subset of the linear frequency modulation pulses change the waveform parameters. Based on the way the parameters vary between different radar sources, two effects can occur: i) interference can be suppressed and / or ii) interference can be shaped. Shaping the interference can include time delaying and frequency shifting the interference beyond the range that the receiver can detect. By properly selecting the parameters of the waveform, the waveforms of the coexisting radars can be orthogonalized so that they do not interfere with each other in a way that affects target detection performance. Two parameters that can be used to shape or suppress interference can be the slope β and the frequency offset f 0 , which may be two parameters that characterize the FMCW waveform. The pattern in which such parameters may be varied may be random or taken from a set of possible patterns (e.g., a codebook) designed to ensure low mutual interference. Some processing at the receiver may be used to coherently combine the reflections of the received chirp.

[0141] As mentioned above, the interference can be randomized by varying the FMCW parameters for each chirp. Two waveform parameters that can vary from chirp to chirp are the slope β and the frequency offset f 0 The following equation describes the received processed waveform r[m,n] after coherent detection, where the slope β and the frequency offset f 0 With each chirp:

[0142]

[0143] Where K φ (m) =exp(-jπ(β (m)t 0 -f 0 (m) )t 0 ),β (m) is the slope of the mth linear frequency modulation pulse, f 0 (m) is the frequency offset of the mth chirp, m is the chirp index, λ is the wavelength, T C is the period or duration of the chirp, F s is the sampling rate at the receiver, v is the velocity of the target, N c is the total number of chirps on which the parameter change is performed, n is the sample index, and t 0 is the time offset of the target.

[0144] If the slope and offset parameters are changed, two parameters may undergo additional receiver processing: (1) The phase term K φ (m) , may no longer be constant across the chirp and may vary from chirp to chirp (e.g., corresponding to changes in the slope and frequency offset of the chirp), and (2) the phase ramp corresponding to the time delay (i.e., dependent on the index n) may also vary from chirp to chirp as the slope of the chirp changes. Thus, using the varying waveform parameters, changes may be implemented in the receiver processing such that the desired signal may still be coherently combined using equalization and resampling. In one example, the desired signal may be a reflected target signal. The second exponential term may represent a time delay phase ramp term, while the first exponential term may represent a Doppler phase ramp term. Due to the slope β and the frequency offset f 0 can vary with the linear frequency modulation pulse m, so the phase term K φ (m) K may also vary with the chirp index m. Because they may have different phases, different chirps cannot be combined until they are equalized, where the equalization can take into account the fact that the phase between chirps is not constant and can correct for phase variations from chirp to chirp. However, K φ (m) It may also depend on the time delay of the target and may not be known a priori at the receiver. Therefore, equalization of the received waveform itself may not be possible. However, in some cases it may be possible to make K φ (m) is equal to the phase constant.

[0145] Fig. 9An equalization process 900 is depicted in accordance with aspects of the present disclosure, which may be performed after a fast time-delayed DFT 925 (e.g., a DFT performed on a single chirp 915-a, 915-b, 915-c). The equalization process 900 may be performed on one or more chirps 915 (e.g., chirps 915-a, 915-b, 915-c, etc.) received in a time dimension 910 and having the same frequency range 905 and frequency offset 920. In one example, for each time t 0 , K φ (m) can be equalized regardless of whether there are existing paths. In this case, the noise statistics can remain unchanged and the signals can be coherently combined by a second DFT (e.g., a slow-time DFT).

[0146] The following equations (eg, Equations 8 and 9) describe an equalizer that may be used (eg, in equalization process 900) to equalize phase variations on m:

[0147]

[0148] The slope β (m) is the slope of the mth linear frequency modulation pulse, f 0 (m) is the frequency offset of the mth chirp, m is the chirp index, l is the time delay peak, W (m) is the equalizer for the mth chirp, and T C is the duration of the chirp. After performing a fast DFT on the chirp, W (m) [l] to process the received reflected signal. Note that the target peak of the processed signal can vary with the chirp index m. The following equation discloses the phase term K φ (m) , this phase term varies from chirp to chirp and can be equalized before the reflections from the chirps are added:

[0149]

[0150] Where K φ (m) =exp(-jπ(β (m) t 0 -f 0 (m) )t 0 ), m is the chirp index, β (m) is the mth slope, λ is the wavelength, T C is the period or duration of the chirp, Fs is the sampling rate at the receiver, v is the velocity, N c is the total number of chirp parameters over which the waveform parameters are changed, k is the Doppler bin index, l is the time delay bin index, δ is the Dirac-delta function, t 0 is the time offset of the target.

[0151] Equalization and resampling may occur after fast time DFT processing 925 at the receiver. The interference peak position after fast time DFT 925 may depend on the slope β of a given chirp 915. In some cases, the equalization process 900 and resampling may be performed using the assumption that the sampling rate does not change. Fig.10 As further described, the delay resolution and maximum delay can therefore vary for each chirp 915 (depending on the chirp slope variation). After applying the fast-time DFT 925, resampling and zero appending can be applied to the slope β of the processed reflected radar waveform. For example, for a signal with β (m) =2β, the resampling process may need to keep every even sample of the fast time DFT 925 output, which results in a vector of half the length of the original fast time DFT 925 output, and append zeros at the end to return to the original size of the vector.

[0152] Fig.11 Receiver processing 1100 for target detection to accommodate waveform parameters that vary from chirp to chirp in accordance with aspects of the present disclosure is shown, where equalization and resampling may be performed after a fast-time DFT 1120. The UE 120 may receive a plurality of reflected chirps 1119 (e.g., 1119-a, 1119-b, 1119-c, etc.) in the time domain 1114, where the reflected chirps 1119 may have the same frequency range 1109. After performing the fast-time DFT 1120, a peak 1132 may be located at a position having F s ×T C The time delay grids 1130 (e.g., time delay grids 1130-a, 1130-b, 1130-c, etc.) of a grid size 1125 may be in intervals. The location of the peaks 1132 in each time delay grid 1130 may depend on the actual waveform parameters used. In one example, the first time delay grid 1130-a may have a peak 1132-a in interval 2, the second time delay grid 1130-b may have a peak 1132-b in interval 3, and the third time delay grid 1130-c may have a peak 1132-c in interval 6 (e.g., the peaks may be represented by cross-hatched intervals).

[0153] To account for the variation in bin positions, equalization and resampling may be performed after the fast time DFT processing 1120 at the receiver. The purpose of resampling may be to convert all fast time DFT 1120 chirp outputs (e.g., from 0 to N) into c ) are aligned to the same time delay interval. Equalization can be performed to ensure that the output of the fast time DFT 1120 has the same phase, where the phase can be aligned. Once the output of the fast time DFT 1120 (e.g., time delay grid 1130) is equalized and resampled (e.g., in time delay grid 1140), the output can be passed to the slow time DFT 1145, which can ensure that the target peak is placed in the correct time delay interval. For example, if there is a preferred interval room for the target peak, and the target peak appears in an interval that is not a preferred interval, the waveform parameters can be changed until the peak appears in the preferred interval. The slow time DFT 1145 can create a time delay Doppler grid 1150. As described above with reference to Figure 7, the CFAR detector 1160 can be applied to the time delay Doppler grid 1150.

[0154] Fig.10 1000 according to various aspects of the present disclosure. C The resampling process 1000 is performed based on one or more linear frequency modulation pulses received during the time period 1015-a. In one example, the first linear frequency modulation pulse received in the time period 1015-a may have a slope β (1) , and can have a value of β (m) T c t (0) The second chirp (eg, received in time period 1015-b) may be received at twice the slope β (2) =2β (1) to be sent, and may have a value of 2β (1) T c t (0) peak within the delay interval of . Due to the doubling of the slope, the second linear frequency modulation pulse can be sampled every other interval (e.g., interval 0, interval 2, interval 4, etc.). Therefore, the second linear frequency modulation pulse can be resampled to every even interval (e.g., due to its slope being doubled than the first linear frequency modulation pulse) so that the target peak of the second linear frequency modulation pulse appears in the same interval as the first linear frequency modulation pulse. Zeros can be appended so that the resampled fast-time DFT output of each linear frequency modulation pulse has the same size. In some cases, if the slope β is doubled, the same B Hz (e.g., frequency range 1005) can be covered in half the time, and the resampling (e.g., sampling the even intervals and discarding the odd intervals) can result in a common slope β.

[0155] For a given chirp and chirp set, an interfering radar signal at an unmatched receiver may have an effect. The interfering signal may have a different slope β and frequency offset f than the target (e.g., reflected) signal. 0 For example, for a given linear frequency modulation pulse, the frequency shift f 0 And / or the slope β may vary between the interference signal and the target signal.

[0156] Frequency deviation f 0 The mismatch of and the matching of the slope β between the target signal and the interference signal can result in a shift of the interference peak in the time delay domain. In one example, the interference peak can be shifted outside the range of interest. The following equation describes the processing at the mismatched receiver:

[0157]

[0158] Where l is the time delay peak, k is the Doppler peak, β is the slope of the desired radar and the jammer radar, and f 0 is the desired radar frequency offset, f′ 0 is the frequency offset of the jamming radar, λ is the wavelength, T C is the period or duration of the chirp, F s is the sampling rate at the receiver, v is the relative velocity, N c is the total number of chirps on which the parameter change is performed, n is the sample index, and t 0 is the time offset and δ is the Dirac-delta function.

[0159] For a given chirp, the mismatch slope β between the target and interference signals and the frequency offset f of the match or mismatch are 0 This can cause the interference energy to spread out in the time delay domain, and in one example, it can behave like noise and be distributed in the time delay domain. If concentrated on multiple chirps (e.g., due to slow-time DFT processing), chirps with mismatched frequency offsets and matched slopes can distribute interference peaks in the Doppler domain, but can maintain the same offset in the time delay domain.

[0160] Fig.12 An example 1200 of a chirp is shown for which the interference peak is located in the time delay interval, but when multiple chirps are aggregated, the interference spreads out in the Doppler domain. For a single chirp, the interference peak is represented by Fig.12 Indicated by the arrow in the Fig.12, which is illustrated by the cross-hatched rectangle, shows that when multiple linear frequency modulation pulses are aggregated, the energy of linear frequency modulation pulses with matching slopes and unmatched frequency offsets is spread in the Doppler domain. The peak remains in the same time delay interval, but is further spread in the Doppler dimension. The time delay interval where the interference peak shifts depends on the value of the frequency offset. Similarly, when aggregated on multiple linear frequency modulation pulses (e.g., due to slow-time DFT processing), linear frequency modulation pulses with unmatched slopes and matched or unmatched frequency offsets will cause the interference energy to be spread in the Doppler time delay dimension.

[0161] Certain choices of slope and frequency offset waveform parameters can result in a transmitted FMCW waveform similar to a Zadoff-Chu sequence (ZC) (e.g., assuming Nyquist sampling) as shown in the following equation. In the following equation, for a given linear frequency chirp, two parameters u and q can be used to determine the slope and frequency offset of the linear frequency chirp.

[0162]

[0163] Where m is the chirp index; n is the sample index within the chirp; T C is the period of the linear frequency modulation pulse; B is the frequency range; β (m) is the slope; f 0 (m) is the frequency offset of the mth linear frequency modulation pulse; (u (m) ,q (m) ) are two parameters of the mth linear frequency modulation pulse, which determine the FMCW waveform so that it is similar to the Zadoff-Chu sequence; and, (-1) (.) is the phase term, if BT c is an even number, then it is equal to 1. If BT c If it is an odd number, it is equal to (-1) m , and does not change the Zadoff-Chu sequence form of a given linear frequency modulation pulse.

[0164] In the following equation, the slope of the chirp m can be chosen to be β (m) =u (m) ×B / T c , and the frequency offset can be selected as f 0 (m) =u (m) ×(1+2q (m) ) / T c , so that the linear FM pulse slope and frequency offset satisfy the following parameterization:

[0165]

[0166] Where m is the chirp index; Where T C is the period of the linear frequency modulation pulse; B is the frequency range; β (m) is the slope; f 0 (m) is the frequency offset of the mth linear frequency modulation pulse; (u (m) ,q (m) ) are two parameters of the mth linear frequency modulation pulse, which determine the FMCW waveform to make it similar to the Zadoff-Chu sequence and can be called Zadoff-Chu parameters. Based on the Zadoff-Chu parameters u and q, the Zadoff-Chu waveform can respond to the slope β and the frequency offset f 0 By selecting the slope and frequency offset of the chirp in this manner, the resulting waveform can resemble a Zadoff-Chu waveform, which can have useful properties for suppressing interference and shaping interference, as described herein.

[0167] In some cases, the parameter (u (m) ,q (m) ), so that interference between coexisting radars can be suppressed by exploiting the correlation characteristics of the Zadoff-Chu waveform. If the Zadoff-Chu sequence is applied to a radio signal, an electromagnetic signal with constant amplitude can be generated so that the cyclically shifted versions of the sequence applied to the signal have zero correlation with each other at the receiver. A "root sequence" is a Zadoff-Chu sequence that has not been shifted. These sequences can exhibit the property that the cyclically shifted versions of the root sequence are orthogonal to each other, provided that each cyclic shift (if viewed in the time domain of the signal) is greater than the multipath delay spread and propagation delay of the signal between the transmitter and the receiver. In some cases, u can be referred to as the Zadoff-Chu (Zadoff-Chu) root parameter or the root parameter of the Zadoff-Chu sequence, and q can be referred to as the Zadoff-Chu shift parameter or the shift parameter of the Zadoff-Chu sequence.

[0168] In some aspects, phase modulation can be applied to the FMCW waveform as follows. A phase code sequence can be applied to the FMCW waveform x FMCW [m,n], where the phase code can follow the Zadoff-Chu sequence:

[0169]

[0170] Among them, m is from 1 to N c The linear frequency modulation pulse index; N c is the number of linear frequency modulation pulses; N≤N c is the length of the phase code and can be constrained to be less than or equal to N c; n is the largest prime number of ; n is the sample index within the mth chirp; and Control is performed by Zadoff-Chu sequence in N c The phase modulation applied on the chirp can be based on a Zadoff-Chu sequence and can be adjusted by selecting the parameters As mentioned above, the slope and frequency offset parameters of the FMCW waveform can also be determined in a subset of linear frequency modulation pulses m = 1, 2, ..., N c The waveform may be modified so that it follows a Zadoff-Chu sequence. In this case, the transmitted waveform may resemble two nested Zadoff-Chu sequences: the original FMCW waveform, where each linear frequency modulation pulse resembles a Zadoff-Chu sequence (e.g., based on certain parameter selections); and a Zadoff-Chu representing the phase modulation. The Zadoff-Chu sequence representing the phase sequence applied to the FMCW waveform may help suppress interference of the two waveforms by preventing the waveforms from coherently adding.

[0171] Zadoff-Chu sequences can have useful properties for interference suppression and interference shaping. For chirps with different slopes, interference can be suppressed. If two UEs i and j are both transmitting and Then the cross-correlation of the two Zadoff-Chu sequences for i and j can be a low value. Then the cross-correlation between the Zadoff-Chu sequences will increase the noise floor, where there are two radar transmitters for i and j. In one example, i and j can use different slopes on the mth chirp and This may result in the cross-correlation of the two sequences being limited by the length of the Zadoff-Chu sequence. Therefore, interference can be suppressed due to the low cross-correlation between the two Zadoff-Chu sequences. The correlation between the two Zadoff-Chu sequences can increase the noise floor, which means that the two sequences may not be completely orthogonal. In this way, the cross-correlation can be small but not zero, and the interference can be spread out at a low energy that appears as noise. For mismatched slopes (e.g., parameter u), the cross-correlation Can be constant so that any time-delayed energy can be spread evenly in the time-delay dimension. Interference can be suppressed by the length of the Zadoff-Chu sequence so that the interference can appear as suppressed noise that raises the noise floor (e.g., not as a ghosting target). Therefore, using different sets of u (e.g., root parameters) and q (e.g., shift parameters) as parameters for different Zadoff-Chu sequences can therefore result in interference suppression.

[0172] In another example, the slopes u of the i-th and j-th transmitters can be matched. For example, the interference can be shaped by setting the frequency offset so that the ghost target or interference peak appears outside the range of interest. That is, the root Zadoff-Chu parameter of the i-th transmitter of the m-th linear frequency modulation pulse is equal to the root Zadoff-Chu parameter of the j-th transmitter of the m-th transmitter. The peak interference may be relative to The shift can therefore be represented by the difference between the Zadoff-Chu q (e.g., shift) parameter of the ith transmitter of the mth chirp and the Zadoff-Chu q (e.g., shift) parameter of the jth transmitter of the mth chirp. Thus, if the root Zadoff-Chu parameters of the ith and jth transmitters are the same, the shift can be represented by the difference between the shifted Zadoff-Chu parameters of the ith and jth transmitters. If the values ​​of the q Zadoff-Chu parameters are close to each other, the peaks can be shifted more than when the parameters are far apart.

[0173] In one example, the peak interference may be set to be greater than the range of interest, where m is the mth chirp and i,j are radar transmitters. For example, a radar may be aimed at a range of 150 meters, may transmit at a bandwidth of 1 GHz, may receive at a sampling rate of 1 GHz, and may have a chirp duration T of 10 microseconds. C Thus, if the root Zadoff-Chu parameter of the ith transmitter of the mth chirp is equal to the root Zadoff-Chu parameter of the jth transmitter of the mth chirp, then The difference between the shifted Zadoff-Chu parameters of the ith and jth transmitters can be set between frequency offsets of [1000 Hz, 9000 Hz] so that mutual interference between the i-th and j-th transmitters will occur at distances greater than 150 meters, which may be beyond the expected range of any target reflection signal. Therefore, if the root Zadoff-Chu parameter u of the chirp m of radar transmitters i and j is (m) If the same, the q or shifted Zadoff-Chu parameters of radar transmitters i and j of the mth linear frequency modulation pulse can be selected and The peak of interference can be shifted outside the range of interest. In one example, if radar transmitters are adjacent to each other, their energy can still appear to be far away from each other and not act as interference within the interference range. Therefore, the matched slope u and the mismatched offset q can result in an autocorrelation between transmitters i and j such that the interference peak can be delayed relative to the mismatch in q.

[0174] In one example, the aggregation can be performed with a varying slope u (m) and frequency offset f (m) For multiple linear frequency modulation pulses with mismatched slopes For a linear frequency modulation pulse with matching slope u (e.g., the i-th and j-th transmitter of the m-th linear frequency modulation pulse) and mismatch q (e.g., the i-th and j-th transmitter of the m-th linear frequency modulation pulse) and ) of the chirp, due to the difference between the frequency offsets of the ith and jth transmitters of the mth chirp (e.g., ) related delay, the interference can be distributed in the Doppler dimension.

[0175] In some cases, if FMCW is used as the waveform, the choice of the values ​​of the root u and shift q parameters of the Zadoff-Chu sequence may be limited due to the variation of the parameters used at the receiver end to handle the changes. In other words, the root u and shift q parameter values ​​(u (m) ,q (m) ) may be restricted (e.g., only a small set of “orthogonal users” are possible), where u (m) is the root parameter of the mth linear frequency modulation pulse, q (m) is the shift parameter of the mth chirp. Due to receive processing (e.g., resampling), several values ​​of the root Zadoff-Chu parameter can be used without affecting the system performance at the receiver. For example, u (m) ∈±[1,2], so that the u or root parameter u of the mth linear frequency modulation pulse (m) Can be 1 or 2. (m) Values ​​other than 1 or 2 may be used, but may affect resolution performance (e.g., if the sampling rate at the receiver is assumed to remain constant to coherently combine N c linear frequency modulation pulse). For example, for u (m) = 3 can be 30 cm, while for u (m)= 1 can be 10 cm (e.g., assuming the receiver sampling rate, number of chirps, and chirp duration (although the slope is increased) remain constant). (m) =2 is the resolution performance of u (m) = 1. Therefore, in one example, u (m) Can be limited to ±1 or ±2.

[0176] Furthermore, in order to meet the maximum range specification where interference is not a concern, several values ​​of q may be feasible for the same Zadoff-Chu root parameter u, q, where u (m) is the root parameter of the mth chirp and q (m) is the shifted Zadoff-Chu parameter of the mth chirp. In one example, the value of q can be selected so that the interference is outside the maximum range specification. For example, in is the shifted Zadoff-Chu parameter of the ith transmitter of the mth chirp, is the shifted Zadoff-Chu parameter of the kth transmitter of the mth chirp, T C is the period of the chirp, B is the frequency range, and u is the Zadoff-Chu root parameter. The parameters can be coherently added as A collection of linear frequency modulated pulses, where are the root parameters and shift parameters of the Zadoff-Chu sequence that determine the slope and offset of the FMCW waveform transmitted by the ith transmitter of the mth chirp, and are the root parameters and shift parameters of the Zadoff-Chu sequence that determine the slope and offset of the FMCW waveform transmitted by the jth transmitter of the mth chirp.

[0177] As previously described, in some aspects, each chirp may use an FMCW waveform that varies waveform parameters from chirp to chirp to mitigate mutual interference. However, as the number of adjacent vehicular radar users increases, the number of interfering chirps may also increase. To prevent the number of FMCW waveforms of different UEs 120 from coherently adding, a phase code (e.g., a phase-coded FMCW waveform) may be added on top of the FMCW waveform. Thus, to suppress interference, a phase code may be added for N c At least a subset of the linear frequency modulation pulses changes the waveform parameters (for example, N cA waveform composed of linear frequency modulation pulses) and a phase code can be applied so that the parameter change and the phase code are different among neighboring automotive radars. In one example, the parameter of the change can be determined from a set of possible patterns (e.g., codewords), where the pattern of the parameter (e.g., linear frequency modulation pulse slope, frequency offset, another waveform parameter, or a combination of any of these) can be referred to as a codeword and the set of patterns can be referred to as a codebook. In some aspects, the codebook can include at least three different codewords, which can correspond to, for example, at least three different linear frequency modulation pulse slopes, at least three different frequency offsets, and / or at least three different linear frequency modulation slope and frequency offset pairs.

[0178] In a phase-coded FMCW system, avoiding coherent addition of chirps with the same parameters can help suppress interference. In one example, 90% of the chirps can be orthogonal (e.g., the parameters of each chirp can be selected so that interference between chirps is suppressed or shaped). In some cases, there are still 10% of the chirps with the same parameters that may coherently add. Therefore, a phase code can be added to the FMCW waveform to suppress or shape interference. The phase code can be based on a set of parameters that result in a low-correlation Zadoff-Chu sequence (e.g., because each chirp has an associated phase and the phase varies from one chirp to another).

[0179] In this example, the A set of chirp pulses can be coherently added. Therefore, a phase code can be added on top of the FMCW to prevent the chirp pulses from adding coherently, thereby suppressing interference. The Zadoff-Chu sequence shown below can be an example of a phase sequence applied to an FMCW waveform, where the FMCW waveform is exponentially increased to the Zadoff-Chu sequence as shown below:

[0180]

[0181] Wherein, m is the chirp index, m = 0, 1, ... N, N is the number of chirps and the length of the Zadoff-Chu sequence, n is the sample index of the mth chirp, and and Controlling the phase modulation applied to each of the parameters is called phase modulation. Adding the phase code can create two nested Zadoff-Chu sequences: the original FMCW waveform, where each chirp resembles a Zadoff-Chu sequence; and the Zadoff-Chu representing the phase modulation. The Zadoff-Chu sequence for the phase sequence applied to the FMCW waveform can produce interference suppression between the two waveforms by preventing interference from the waveforms from adding coherently.

[0182] The processing at the receiver end may also be changed so that the desired signal can be coherently combined using equalization and resampling. In one example, the parameters may be selected by selecting codewords from a codebook, where each codeword represents a pattern of waveform parameters and each codebook contains multiple codewords for a pattern. Specifically, the codeword may represent N c A codebook is a set of codewords with different parameter patterns. The parameter changes can be selected from a codebook designed for low mutual interference between codewords. For example, if a vehicle shares its parameter codewords with another vehicle via a sidelink, the other vehicle can select a codeword with parameters that cause less mutual interference between the two vehicles.

[0183] As described above, parameters can be selected by selecting codewords from a codebook, where the codebook can be designed to produce low mutual interference between other users in the system. If the parameter pattern (e.g., codeword) used by a vehicle with transmitter i is known to a vehicle with transmitter j, the vehicle with transmitter j can select the codeword that produces the least mutual interference with the parameter pattern used by the vehicle with transmitter i. In one example, the vehicle with transmitter i can first determine the set of patterns used by other vehicles in its vicinity, and select the codeword for its own transmission that causes the least mutual interference. Interference can be detected by observing the received signal or signal energy on the parameter pattern in the codeword. The vehicle can select the codeword that is most orthogonal (e.g., causes the least mutual interference) to the codeword detected to be used in the vicinity of the vehicle.

[0184] In one example, a codeword may contain a subset of the values ​​of the parameters found in the following codeword parameter sets:

[0185]

[0186] Among them, c i is the parameter set of the ith codeword, which determines the slope and frequency offset of the FMCW waveform transmitted in the linear frequency modulation pulse m; is the slope of the FMCW waveform of the ith codeword of the mth linear frequency modulation pulse; is the frequency offset of the FMCW waveform of the ith codeword of the mth chirp, and where is the phase modulation of the i-th codeword applied to the m-th chirp, and where m is the chirp index; and, N c is the total number of chirps over which a parameter change is performed.

[0187] In one example, the codeword may contain the value of the FMCW parameter found in the following codeword parameter set:

[0188]

[0189] in, is the root Zadoff-Chu parameter of the ith transmitter of the mth chirp, is the shifted Zadoff-Chu parameter of the ith transmitter of the mth chirp, c i is the set of parameters for the ith transmitter that determine the slope and frequency offset of the FMCW waveform transmitted in chirp m, where m is the chirp index and N c is the total number of chirps over which the parameter change is performed, and Controlled in N c The phase modulation applied on the chirp is referred to as the phase modulation parameter.

[0190] In one example, the parameters of the i-th codeword may be randomly selected with a uniform distribution within the parameter's range of interest. In one example, the parameters of the i-th codeword may be selected as The interference between vehicle radars using different codewords is suppressed or shaped or both, where c i is the set of parameters that controls the slope and frequency offset of the mth chirp, is the slope parameter of the mth linear frequency modulation pulse, is the frequency offset parameter of the mth linear frequency modulation pulse, m is the linear frequency modulation pulse index, N c is the total number of chirps on which interference suppression is performed.

[0191] Fig.13 A process 1300 is shown in accordance with aspects of the present disclosure. Process 1300 describes steps that may be taken by UE 120 to select FMCW waveform parameters for multiple radar coexistence, and process reflected radar waveforms (eg, by equalizing and resampling the reflected radar waveforms).

[0192] At 1310, UE 120 may determine to change the waveform parameters of the radar and send a signal transmitted by N c A radar waveform consisting of a linear frequency modulated pulse.

[0193] At 1320, UE 120 may suppress interference to chirps having different slopes.

[0194] At 1330, UE 120 may shape the interference by setting a frequency offset so that the interference peak appears outside the range of interest.

[0195] At 1340, UE 120 may apply phase modulation to avoid coherent addition of chirps having the same slope and the same frequency offset parameters.

[0196] At 1350, UE 120 may select a slope and a frequency offset of the FMCW waveform such that the FMCW waveform resembles a Zadoff-Chu sequence.

[0197] At 1360 , UE 120 may select a codeword that is orthogonal to the codeword detected to be used in the vicinity of UE 120 .

[0198] At 1365, UE 120 may randomly select a codeword with a uniform distribution within the range of interest for slope u and frequency offset q.

[0199] At 1370, UE 120 may select waveform parameters based on a codebook comprising at least one codeword for the parameter.

[0200] At 1375 , UE 120 may receive and process the reflected radar waveform by applying a fast-time DFT to the reflected waveform and applying a slow-time DFT to the reflected waveform.

[0201] At 1380, UE 120 may further process the reflected radar waveform by equalizing the reflected radar waveform after applying the fast-time DFT. UE 120 may also resample the reflected radar waveform after applying the fast-time DFT.

[0202] At 1385, UE 120 may further process the reflected radar waveform by appending zeros.

[0203] Fig.141401. Certain components that may be included in a base station 1401 according to various aspects of the present disclosure are shown. The base station 1401 may be an access point, a NodeB, an evolved NodeB, etc. The base station 1401 includes a processor 1403. The processor 1403 may be a general-purpose single-chip or multi-chip microprocessor (e.g., an ARM), a dedicated microprocessor (e.g., a digital signal processor (DSP)), a microcontroller, a programmable gate array, etc. The processor 1403 may be referred to as a central processing unit (CPU). Although in Fig.14 Just a single processor 1403 is shown in the base station 1401 , but in an alternative configuration, a combination of processors (eg, an ARM and DSP) could be used.

[0204] The base station 1401 also includes a memory 1405. The memory 1405 may be any electronic component capable of storing electronic information. The memory 1405 may be embodied as a random access memory (RAM), a read-only memory (ROM), a magnetic disk storage medium, an optical storage medium, a flash memory device in a RAM, on-board memory included in a processor, EPROM memory, EEPROM memory, registers, etc., including combinations thereof.

[0205] Data 1407 and instructions 1409 may be stored in memory 1405. Instructions 1409 may be executed by processor 1403 to implement the methods disclosed herein. Executing instructions 1409 may involve using data 1407 stored in memory 1405. When processor 1403 executes instructions 1409, various portions of instructions 1409a may be loaded onto processor 1403, and various data 1407a may be loaded onto processor 1403.

[0206] The base station 1401 may also include a transmitter 1411 and a receiver 1413 to allow signals to be transmitted to and received from the wireless device 1401. The transmitter 1411 and the receiver 1413 may be collectively referred to as a transceiver 1415. Multiple antennas 1417a-b may be electrically coupled to the transceiver 1415. The base station 1401 may also include (not shown) multiple transmitters, multiple receivers, and / or multiple transceivers.

[0207] The various components of the base station 1401 may be coupled together via one or more buses, which may include a power bus, a control signal bus, a status signal bus, a data bus, etc. For clarity, the various buses are described in Fig.14 is shown as bus system 1419. Although discussed with reference to UE Fig.13 , but it should be understood that a base station such as base station 1401 may perform the corresponding transmission received and monitored by the UE and the corresponding transmission received and monitored by the UE. Fig.13 The reception of the UE indicated information discussed in Fig.14 The described in the embodiment is implemented in software executed by the processor 1403.

[0208] Fig.15 1 shows certain components that may be included in a wireless communication device 1501 according to various aspects of the present disclosure. The wireless communication device 1501 may be an access terminal, a mobile station, a user equipment (UE), etc. The wireless communication device 1501 includes a processor 1503. The processor 1503 may be a general-purpose single-chip or multi-chip microprocessor (e.g., ARM), a dedicated microprocessor (e.g., a digital signal processor (DSP)), a microcontroller, a programmable gate array, etc. The processor 1503 may be referred to as a central processing unit (CPU). Although in Fig.15 Only a single processor 1503 is shown in the wireless communication device 1501 of FIG. 1 , but in an alternative configuration, a combination of processors (eg, an ARM and DSP) could be used.

[0209] The wireless communication device 1501 also includes memory 1505. The memory 1505 may be any electronic component capable of storing electronic information. The memory 1505 may be embodied as a random access memory (RAM), a read-only memory (ROM), a magnetic disk storage medium, an optical storage medium, a flash memory device in a RAM, on-board memory included in a processor, EPROM memory, EEPROM memory, registers, etc., including combinations thereof.

[0210] Data 1507 and instructions 1509 may be stored in memory 1505. Instructions 1509 may be executed by processor 1503 to implement the methods disclosed herein. Executing instructions 1509 may involve using data 1507 stored in memory 1505. When processor 1503 executes instructions 1509, various portions of instructions 1509a may be loaded onto processor 1503, and various data 1507a may be loaded onto processor 1503.

[0211] The wireless communication device 1501 may also include a transmitter 1511 and a receiver 1513 to allow signals to be sent to and received from the wireless communication device 1501. The transmitter 1511 and the receiver 1513 may be collectively referred to as a transceiver 1515. Multiple antennas 1517a-b may be electrically coupled to the transceiver 1515. The wireless communication device 1501 may also include (not shown) multiple transmitters, multiple receivers, and / or multiple transceivers.

[0212] The various components of the wireless communication device 1501 may be coupled together via one or more buses, which may include a power bus, a control signal bus, a status signal bus, a data bus, etc. For clarity, the various buses are described in Fig.151519. It should be noted that these methods describe possible implementations, and that the operations and steps may be rearranged or otherwise modified so that other implementations are possible. In one example, aspects from two or more methods may be combined. For example, aspects of each method may include steps or aspects of other methods, or other steps or techniques described herein. Thus, aspects of the present disclosure may provide for receiving while sending and sending while receiving. Fig.13 The functions described in the flowchart may be implemented in hardware or by a similar Fig.15 The processor 1503 described in the above is implemented by executing software.

[0213] Fig.16 A flow chart illustrating a method 1600 according to aspects of the present disclosure is shown, which illustrates a method for selecting waveform parameters and processing a reflected waveform. The operations of the method 1600 may be implemented by a UE 120 or a component thereof as described herein. In some examples, the UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, the UE may use dedicated hardware to perform various aspects of the functions described below.

[0214] At 1605, the UE may select a set of waveform parameters from a codebook of waveform parameters for transmitting a corresponding set of linear frequency modulation pulses associated with the radar waveform. The operation of 1605 may be performed according to the methods described herein. In some examples, the UE may be implemented in hardware, by a processor such as Fig.15 The processor 1503 described in the above may execute software to implement various aspects of the operation of 1605 .

[0215] At 1610, the UE may send a set of chirp pulses according to a corresponding set of waveform parameters. The operations of 1610 may be performed according to the methods described herein. In some examples, the UE may be implemented in hardware, by a processor such as Fig.15 The processor 1503 described in the above may execute software to implement various aspects of the operation of 1605 .

[0216] At 1615, the UE may receive a reflected radar waveform from a target, the reflected radar waveform including a set of reflected chirp pulses corresponding to a set of chirp pulses. The operations of 1615 may be performed according to the methods described herein. In some examples, the UE may be implemented in hardware, by a processor such as Fig.15 The processor 1503 described in the above may execute software to implement various aspects of the operation of 1605 .

[0217] At 1620, the UE may process the reflected radar waveform based on the set of waveform parameters. The operations of 1620 may be performed according to the methods described herein. In some examples, the UE may be implemented in hardware, by a processor such as Fig.15 The processor 1503 described in the above may execute software to implement various aspects of the operation of 1605 .

[0218] The description herein is provided to enable those skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but should be given the broadest scope consistent with the principles and novel features disclosed herein.

[0219] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the function can be stored on a computer-readable medium or sent via a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the above functions can be implemented using software executed by a processor, hardware, firmware, hard wiring, or any combination of these. The features that implement the functions can also be physically located in various locations, including being distributed so that the various parts of the functions are implemented at different physical (PHY) locations. Moreover, as used herein, including in the claims, the "or" used in a list of items (e.g., a list of items beginning with phrases such as "at least one" or "one or more") indicates an inclusive list, so that, for example, a list of at least one of A, B, or C represents A or B or C or AB or AC or BC or ABC (i.e. A and B and C).

[0220] Computer readable media include both non-transitory computer storage media and communication media, and communication media include any media that helps to transfer a computer program from one place to another.Non-transitory storage media can be any available media that can be accessed by a general or special computer.As an example and not limitation, non-transitory computer readable media can include RAM, ROM, electrically erasable programmable read-only memory (EEPROM), compact disc (CD) ROM or other optical disc storage devices, magnetic disk storage devices or other magnetic storage devices, or can be used to carry or store required program code components in the form of instructions or data structures, and can be accessed by a general or special computer or a general or special processor.Any other non-transitory medium.Moreover, any connection is appropriately referred to as computer readable media.For example, if software is sent from a website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwaves, the definition of medium includes coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwaves. Disk and disc, as used herein, includes CD, laser disc, optical disc, word versatile disc (DVD), floppy disk and Blu-ray disc, where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0221] The technology described herein can be used in various wireless communication systems, such as code division multiple access (CDMA), TDMA, FDMA, OFDMA, single carrier frequency division multiple access (SC-FDMA), and other systems. The terms "system" and "network" are often used interchangeably. A CDMA system can implement radio technologies such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 versions 0 and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system can implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA systems can implement radio technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wireless Fidelity (Wi-Fi)), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (Universal Mobile Telecommunications System (UMTS)). 3GPP LTE and Advanced LTE (LTE-A) are new versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-a, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). CDMA2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The technology described herein can be used for the above-mentioned systems and radio technologies as well as other systems and radio technologies. However, the description herein describes an LTE system for example purposes, and LTE terminology is used in most of the above descriptions, although the technology can be applied outside the application of LTE.

[0222] In LTE / LTE-A networks including the networks described herein, the term evolved Node B (eNB) may be generally used to describe a base station. One or more wireless communication systems described herein may include heterogeneous LTE / LTE-A networks in which different types of eNBs provide coverage for various geographic areas. For example, each eNB or base station may provide communication coverage for a macro cell, a small cell, or other types of cells. The term "cell" is a 3GPP term that can be used to describe a base station, a carrier or component carrier (CC) associated with a base station, or a coverage area (e.g., a sector, etc.) of a carrier or base station, depending on the context.

[0223] A base station may include or may be referred to by those skilled in the art as a base station transceiver, a radio base station, an access point (AP), a radio transceiver, a NodeB, an eNodeB (eNB), a home NodeB, a home eNodeB or some other suitable term. The geographic coverage area of ​​a base station may be divided into sectors that constitute a portion of the coverage area. One or more wireless communication systems described herein may include different types of base stations (e.g., macro cell base stations or small cell base stations). The UE described herein may communicate with various types of base stations and network equipment including macro eNBs, small cell eNBs, relay base stations, etc. For different technologies, there may be overlapping geographic coverage areas. In some cases, different coverage areas may be associated with different communication technologies. In some cases, the coverage area of ​​one communication technology may overlap with the coverage area associated with another technology. Different technologies may be associated with the same base station or different base stations.

[0224] One or more wireless communication systems described herein may support synchronous or asynchronous operation. For synchronous operation, base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for synchronous or asynchronous operation.

[0225] The DL transmission described herein may also be referred to as forward link transmission, and the UL transmission may also be referred to as reverse link transmission. Figure 1 Each communication link of the wireless network 100 may include one or more carriers, where each carrier may be a signal composed of multiple subcarriers (e.g., waveform signals of different frequencies). Each modulated signal may be sent on a different subcarrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc. The communication links described herein may use frequency division duplex (FDD) (e.g., using paired spectrum resources) or time division duplex (TDD) operation (e.g., using unpaired spectrum resources) to send bidirectional communications. Frame structures may be defined for FDD (e.g., frame structure type 1) and TDD (e.g., frame structure type 2).

[0226] Therefore, aspects of the present disclosure can provide for receiving while sending and sending while receiving.It should be noted that these methods describe possible implementations, and the operations and steps can be rearranged or otherwise modified so that other implementations are possible.In one example, aspects from two or more methods can be combined.

[0227] The various illustrative blocks and modules described in conjunction with the present disclosure may be implemented or executed with a general-purpose processor, digital signal processor (DSP), ASIC, field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration). Therefore, the functions described herein may be performed by one or more other processing units (or cores) on at least one integrated circuit (IC). In various examples, different types of ICs (e.g., structured / platform ASICs, FPGAs, or other semi-custom ICs) may be used, which may be programmed in any manner known in the art. The functions of each unit may also be implemented in whole or in part with instructions contained in a memory, which are formatted to be executed by one or more general-purpose or special-purpose processors.

[0228] In the drawings, similar components or features may have the same reference label. In addition, various components of the same type may be distinguished by following the reference label with a dash and a second label that distinguishes the similar components. If only the first reference label is used in the specification, the description applies to any of the similar components having the same first reference label, regardless of the second reference label.

Claims

1. A method for detecting a target using radar signals implemented by a user equipment (UE), comprising: selecting, from a codebook of waveform parameters, a plurality of waveform parameters for transmitting a corresponding plurality of chirp pulses associated with a radar waveform within a frequency range, the plurality of waveform parameters including a plurality of waveform parameter pairs, each waveform parameter pair including a chirp pulse slope and a frequency offset within the frequency range, wherein at least two of the plurality of waveform parameter pairs include different frequency offsets; transmitting the plurality of chirp pulses within the frequency range according to the corresponding plurality of waveform parameters, wherein each chirp pulse of the plurality of chirp pulses scans the frequency range at least once within a corresponding chirp pulse duration; receiving a reflected radar waveform from the target, the reflected radar waveform including a plurality of reflected chirp pulses corresponding to the plurality of chirp pulses; and processing the reflected radar waveform based at least in part on the plurality of waveform parameters; wherein each chirp pulse slope depends on a corresponding first parameter, and each frequency offset depends on the corresponding first parameter and a corresponding second parameter; wherein each waveform parameter pair satisfies the following parametric relationship: parameter: where β (m) is the linear frequency modulation pulse slope, f 0 (m) is the frequency offset, q (m) is the first parameter, u (m) is the second parameter, B is the frequency range of each linear frequency modulation pulse in the plurality of linear frequency modulation pulses, and T c is the time period of each linear frequency modulation pulse in the plurality of linear frequency modulation pulses; wherein each reflected chirp pulse of the plurality of reflected chirp pulses corresponds to a transmitted chirp pulse of the plurality of chirp pulses, and is associated with the same waveform parameter pair as the corresponding transmitted chirp pulse, and wherein processing the reflected radar waveform includes: identifying a peak in a time delay dimension corresponding to a distance to the target based at least in part on a first reflected chirp pulse associated with a first waveform parameter pair of the plurality of waveform parameters; and identifying a peak in a Doppler dimension corresponding to a Doppler of the target based at least in part on the first reflected chirp pulse and a second reflected chirp pulse associated with a second waveform parameter pair of the plurality of waveform parameters.

2. The method according to claim 1, wherein the plurality of waveform parameters includes at least three different waveform parameters.

3. The method according to claim 1, wherein selecting the plurality of waveform parameters from the codebook includes: randomly selecting the plurality of waveform parameters from the codebook.

4. The method according to claim 1, wherein transmitting the plurality of chirp pulses within the frequency range according to the plurality of waveform parameters includes: transmitting each subsequent chirp pulse of the plurality of chirp pulses according to a waveform parameter pair different from a waveform parameter pair of a previous chirp pulse of the plurality of chirp pulses.

5. The method according to claim 1, wherein transmitting the plurality of chirp pulses within the frequency range according to the plurality of waveform parameters includes: transmitting a first chirp pulse of the plurality of chirp pulses according to a first waveform parameter pair of the plurality of waveform parameters; and A second chirp of the plurality of chirp pulses is transmitted consecutively with the first chirp pulse according to a second waveform parameter pair of the plurality of waveform parameters that is different from the first waveform parameter pair.

6. The method of claim 5, wherein transmitting the plurality of linear frequency modulation pulses within the frequency range according to the plurality of waveform parameters further comprises: include: A third chirp of the plurality of chirp pulses is transmitted according to a third waveform parameter pair of the plurality of waveform parameters that is different from the second waveform parameter pair.

7. The method according to claim 6, in, Transmitting the third chirp includes transmitting the third chirp consecutively with the second chirp.

8. The method according to claim 1, in: BT c is a prime number.

9. The method according to claim 1, further comprising: include: Prior to transmitting two or more chirps, phase modulation is applied to the two or more chirps in the plurality of chirps to reduce coherent addition of chirps in the plurality of chirps transmitted according to the same waveform parameters.

10. The method according to claim 1, in, Each of the plurality of linear frequency modulation pulses corresponds to a linear frequency modulation pulse having the same constant time period T c A loop of the radar waveform.

11. The method according to claim 1, in, Processing the reflected radar waveform includes: applying a first Fourier transform to the first reflected chirp to identify the peak in the time delay dimension; and A second Fourier transform is applied to the first reflected chirp and the second reflected chirp to identify the peak in the Doppler dimension.

12. The method according to claim 11, in, Processing the reflected radar waveform includes: Prior to applying the second Fourier transform, a third Fourier transform is applied to the second reflected chirp and equalizes a first phase of the first reflected chirp with a second phase of the second reflected chirp.

13. The method according to claim 12, in, Processing of reflected radar waveforms includes: After applying the first Fourier transform and the third Fourier transform, the first reflected chirp and the second reflected chirp are resampled to align outputs of the first Fourier transform and the third Fourier transform before applying the second Fourier transform.

14. The method according to claim 1, in, The radar waveform is a frequency modulated continuous wave (FMCW) waveform.

15. The method according to claim 1, in, The radar waveform is a phase-coded frequency modulated continuous wave (FMCW) waveform.

16. An apparatus implemented by a user equipment UE for detecting a target using a radar signal, include: means for selecting from a codebook of waveform parameters a plurality of waveform parameters for transmitting a corresponding plurality of chirp pulses associated with a radar waveform within a frequency range, the plurality of waveform parameters comprising a plurality of waveform parameter pairs, each waveform parameter pair comprising a chirp slope and a frequency offset within the frequency range, wherein at least two of the plurality of waveform parameter pairs comprise different frequency offsets; means for transmitting the plurality of chirps within the frequency range in accordance with the corresponding plurality of waveform parameters, wherein each chirp of the plurality of chirps sweeps through the frequency range at least once within a corresponding chirp duration; means for receiving a reflected radar waveform from the target, the reflected radar waveform comprising a plurality of reflected chirps corresponding to the plurality of chirps; as well as means for processing the reflected radar waveform based at least in part on the plurality of waveform parameters; wherein each linear frequency modulation pulse slope depends on a corresponding first parameter, and each frequency offset depends on the corresponding first parameter and a corresponding second parameter; Among them, each waveform parameter pair satisfies the following parameterization relationship: parameter: where β (m) is the linear frequency modulation pulse slope, f 0 (m) is the frequency offset, q (m) is the first parameter, u (m) is the second parameter, B is the frequency range of each linear frequency modulation pulse in the plurality of linear frequency modulation pulses, and T c is the time period of each linear frequency modulation pulse in the plurality of linear frequency modulation pulses; wherein each reflected chirp of the plurality of reflected chirps corresponds to a transmitted chirp of the plurality of chirps and is associated with a same pair of waveform parameters as the corresponding transmitted chirp, and wherein the means for processing the reflected radar waveform: identifying a peak in a time delay dimension corresponding to a distance to a target based at least in part on a first reflected chirp associated with a first waveform parameter pair of the plurality of waveform parameters, and A peak in a Doppler dimension corresponding to a Doppler of the target is identified based at least in part on the first reflected chirp and a second reflected chirp associated with a second waveform parameter pair in the plurality of waveform parameters.

17. The device according to claim 16, in, The plurality of waveform parameters include at least three different waveform parameters.

18. The device according to claim 16, in, Selecting the plurality of waveform parameters from the codebook includes: randomly selecting the plurality of waveform parameters from the codebook.

19. The device according to claim 16, in, The means for transmitting the plurality of chirps within the frequency range transmits each subsequent chirp of the plurality of chirps according to a different pair of waveform parameters than a previous chirp of the plurality of chirps.

20. The device according to claim 16, in, means for transmitting the plurality of chirp pulses within the frequency range according to the plurality of waveform parameters: transmitting a first chirp of the plurality of chirp pulses according to a first pair of waveform parameters of the plurality of waveform parameters, and A second chirp of the plurality of chirp pulses is transmitted consecutively with the first chirp pulse according to a second waveform parameter pair of the plurality of waveform parameters that is different from the first waveform parameter pair.

21. The device according to claim 20, in, The means for transmitting the plurality of chirps within the frequency range according to the plurality of waveform parameters transmits a third chirp of the plurality of chirps according to a third waveform parameter pair of the plurality of waveform parameters that is different from the second waveform parameter pair.

22. The device according to claim 16, in, The means for processing the reflected radar waveform: applying a first Fourier transform to said first reflected chirp to identify said peak in said time delay dimension, and A second Fourier transform is applied to the first reflected chirp and the second reflected chirp to identify the peak in the Doppler dimension.

23. An apparatus implemented by a user equipment UE for detecting a target using a radar signal, include: processor; a memory coupled to the processor; as well as instructions stored in the memory and executable by the processor to cause the apparatus to: selecting a plurality of waveform parameters from a codebook of waveform parameters for transmitting a corresponding plurality of chirp pulses associated with a radar waveform within a frequency range, the plurality of waveform parameters comprising a plurality of waveform parameter pairs, each waveform parameter pair comprising a chirp slope and a frequency offset within the frequency range, wherein at least two of the plurality of waveform parameter pairs comprise different frequency offsets; transmitting the plurality of chirps within the frequency range according to the corresponding plurality of waveform parameters, wherein each chirp of the plurality of chirps sweeps through the frequency range at least once within a corresponding chirp duration; receiving a reflected radar waveform from the target, the reflected radar waveform comprising a plurality of reflected chirps corresponding to the plurality of chirps; as well as processing the reflected radar waveform based at least in part on the plurality of waveform parameters; wherein each linear frequency modulation pulse slope depends on a corresponding first parameter, and each frequency offset depends on the corresponding first parameter and a corresponding second parameter; Among them, each waveform parameter pair satisfies the following parameterization relationship: parameter: where β (m) is the linear frequency modulation pulse slope, f 0 (m) is the frequency offset, q (m) is the first parameter, u (m) is the second parameter, B is the frequency range of each linear frequency modulation pulse in the plurality of linear frequency modulation pulses, and T c is the time period of each linear frequency modulation pulse in the plurality of linear frequency modulation pulses; wherein each reflected chirp of the plurality of reflected chirps corresponds to a transmitted chirp of the plurality of chirps and is associated with a same pair of waveform parameters as the corresponding transmitted chirp, and wherein processing the reflected radar waveform comprises: identifying a peak in a time delay dimension corresponding to a range of the target based at least in part on a first reflected chirp associated with a first waveform parameter pair of the plurality of waveform parameters; and A peak in a Doppler dimension corresponding to a Doppler of the target is identified based at least in part on the first reflected chirp and a second reflected chirp associated with a second waveform parameter pair in the plurality of waveform parameters.

24. A non-transitory computer-readable medium storing code implemented by a user equipment (UE) for detecting a target using a radar signal, the code comprising instructions executable by a processor to: selecting a plurality of waveform parameters from a codebook of waveform parameters for transmitting a corresponding plurality of chirp pulses associated with a radar waveform within a frequency range, the plurality of waveform parameters comprising a plurality of waveform parameter pairs, each waveform parameter pair comprising a chirp slope and a frequency offset within the frequency range, wherein at least two of the plurality of waveform parameter pairs comprise different frequency offsets; transmitting the plurality of chirps within the frequency range according to the corresponding plurality of waveform parameters, wherein each chirp of the plurality of chirps sweeps through the frequency range at least once within a corresponding chirp duration; receiving a reflected radar waveform from the target, the reflected radar waveform comprising a plurality of reflected chirps corresponding to the plurality of chirps; as well as processing the reflected radar waveform based at least in part on the plurality of waveform parameters; wherein each linear frequency modulation pulse slope depends on a corresponding first parameter, and each frequency offset depends on the corresponding first parameter and a corresponding second parameter; Among them, each waveform parameter pair satisfies the following parameterization relationship: parameter: where β (m) is the linear frequency modulation pulse slope, f 0 (m) is the frequency offset, q (m) is the first parameter, u (m) is the second parameter, B is the frequency range of each linear frequency modulation pulse in the plurality of linear frequency modulation pulses, and T c is the time period of each linear frequency modulation pulse in the plurality of linear frequency modulation pulses; wherein each reflected chirp of the plurality of reflected chirps corresponds to a transmitted chirp of the plurality of chirps and is associated with a same pair of waveform parameters as the corresponding transmitted chirp, and wherein processing the reflected radar waveform comprises: identifying a peak in a time delay dimension corresponding to a range of the target based at least in part on a first reflected chirp associated with a first waveform parameter pair of the plurality of waveform parameters; and A peak in a Doppler dimension corresponding to a Doppler of the target is identified based at least in part on the first reflected chirp and a second reflected chirp associated with a second waveform parameter pair in the plurality of waveform parameters.

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