Resource allocation method for 5G NR V2X compatible vehicle-to-everything (V2X) communication and sensing integrated system

Abstract

This invention discloses a resource allocation method for a 5G NR V2X-compatible vehicle-to-everything (V2X) integrated sensing system. This method effectively integrates radar and communication functions at the MAC layer while remaining compatible with existing 5G NR V2X communication protocols. This allows vehicles to coexist with vehicles operating only under the 5G NR V2X protocol that only have communication functions, facilitating the deployment of the integrated system within existing vehicle communication networks. Furthermore, this invention considers the possibility of different vehicle priorities in V2X systems where radar and communication coexist. Different system parameters are allocated for different priorities, and new control information is added to automatically adjust vehicle resource usage when spectrum resources are scarce, ensuring that high-priority vehicles can use spectrum resources preferentially.

Description

Technical Field

[0001] This invention belongs to the field of vehicle-to-everything (V2X) communication technology, and specifically relates to a resource allocation method for a V2X-compatible integrated sensing and communication system. Background Technology

[0002] With the continuous development of intelligent vehicles, vehicles need to be able to obtain accurate perception information by sensing the surrounding environment through radar. Furthermore, 3GPP Release 17 requires vehicles to support enhanced communication applications, such as extended sensing and cooperative control. This requires vehicles to accurately acquire various types of perception information and achieve information fusion between vehicles through high-speed communication. However, with the rapid growth in the number and data volume of in-vehicle intelligent devices, available spectrum resources are becoming increasingly scarce, especially in the millimeter-wave band. Spectrum resources used for communication and radar may conflict, necessitating the conservation of spectrum resources as much as possible. The high integration of intelligent vehicles imposes many limitations on the size and transmission power of in-vehicle equipment, requiring the simplification of equipment to save space and energy. In addition, communication systems also require radar detection assistance to simplify channel estimation and improve beam alignment of the communication system through radar detection results. To meet these needs, the research and design of Integrated Sensing and Communication (ISAC) systems are receiving increasing attention, aiming to simultaneously realize radar and communication functions on the same frequency band and the same device.

[0003] To improve spectrum utilization efficiency and enable shared waveforms for radar and communication in vehicle-to-everything (V2X) radar and communication systems, researchers have proposed various technical solutions. For example, the European patent "Orthogonal phase modulation for detection and communication in radar" (applicant: University of Luxembourg, international publication WO2018 / 206681, 2018.11.15) uses a digital communication symbol sequence to orthogonally modulate a phase-modulated continuous wave (PMCW), embedding the communication signal into the PMCW to achieve the integration of the vehicle radar and communication systems. The paper "Multicarrier radar-communications waveform design for RFconvergence and coexistence" (author M.) also demonstrates this approach. Published in IEEE ICASSP 2019, May 2019, pp. 7780-7784, this paper uses multi-carrier signals as the transmitted waveform and proposes algorithms for subcarrier power allocation and radar sensing information processing. The paper "MU-MIMO communications with MIMO radar: From co-existence to joint transmission" (author F. Liu, published in IEEE Trans. Wirel. Commun., vol. 17, no. 4, pp. 2755-2770, Apr. 2018) designs an integrated signal beammap to achieve radar detection of targets while meeting a certain communication signal-to-noise ratio.

[0004] Besides the transmitted waveform, existing literature has proposed many spectrum resource allocation methods for ISAC systems. For example, the European patent "Co-existence of millimeter wave communication and radar" (applicant: Qualcomm, international publication WO2018 / 132220, 2018.07.19) achieves time-division multiplexing of user equipment radar and communication functions by issuing control signaling from the base station, and broadcasts resource occupancy status to other nodes before the radar function is activated to avoid interference. The paper "Deep learning-based range-doppler map reconstruction in automotive radar systems" (author: HWHsu, published in IEEE VTC2021-Spring, Apr.2021, pp.1-7) proposes an "interleaved" time-frequency resource allocation mode, which optimizes the allocation of resource blocks through deep learning to reduce inter-carrier interference between different vehicles.

[0005] While the aforementioned studies have proposed various waveform design and resource methods for ISAC systems and optimized the performance of radar and communication within them, their proposed methods do not consider compatibility with existing vehicle-to-everything (V2X) communication protocols, nor do they account for situations where vehicles may have different priorities when radar and communication coexist. Therefore, designing a Medium Access Control (MAC) protocol to implement the ISAC system and ensure its compatibility with 5G NR V2X protocols is crucial for resolving the spectrum conflict problem between radar and communication devices in V2X systems. Summary of the Invention

[0006] In view of the above, the present invention provides a resource allocation method for a vehicle-to-everything (V2X) communication and sensing integrated system compatible with 5G NR V2X. While realizing the effective integration of radar and communication functions at the MAC layer, it can also be compatible with the original 5G NR V2X communication protocol, so that vehicles can coexist with vehicles that only have communication functions under the 5G NR V2X protocol, which facilitates the deployment of the integrated system in the original vehicle communication network.

[0007] A resource allocation method for a 5G NR V2X-compatible vehicle-to-everything (V2X) sensing and communication integrated system includes the following steps:

[0008] (1) By dividing the space into sectors, a vehicle-to-everything (V2X) communication method based on millimeter-wave directional communication and radar periodic scanning is designed;

[0009] (2) Optimize the vehicle antenna and its transmission and reception directions;

[0010] (3) Determine the spectrum resources required for a single signal transmission by the vehicle, including duration and bandwidth;

[0011] (4) Calculate and determine the signal transmission power and transmission interval (i.e. the time interval between two adjacent radar scans) of the vehicle in the next round of radar scans;

[0012] (5) Calculate and determine the specific time period and frequency band of each signal transmission during the next round of radar scanning of the vehicle.

[0013] Furthermore, the vehicle-to-everything (V2X) ISAC communication method based on millimeter-wave directional communication and radar periodic scanning in step (1) is as follows: the vehicles in the V2X network are required to transmit OFDM (Orthogonal Frequency Division Multiplexing) signals in the form of electromagnetic waves in the millimeter-wave band as an integrated waveform to transmit communication information and acquire radar perception information, and the communication information includes side link control messages (SCI); since the millimeter-wave band has the characteristics of high frequency, short wavelength and severe attenuation, and the vehicle is required to transmit in a directional manner, specifically: the circumference centered on the vehicle is divided into multiple sectors, and the vehicle radar transmits an integrated waveform in one sector each time to perform target detection, and the target detection is performed on each sector in turn to complete one round of radar scanning.

[0014] Furthermore, the vehicle-to-everything (V2X) ISAC communication method includes two modes: unicast and broadcast. In unicast mode, communication and radar use two different beams. That is, while radar detection is performed in one sector, an additional signal is transmitted to another sector where the communication target is located for unicast communication. In broadcast mode, communication and radar use the same beam. That is, radar detection and information transmission are performed simultaneously in the same sector. Completing one round of radar scanning is equivalent to performing an omnidirectional broadcast of information.

[0015] Furthermore, the specific implementation of step (2) is as follows: the vehicle uses two independent phased array antennas as the transmitting antenna and the receiving antenna respectively, and at the same time, the direction of the receiving antenna is consistent with the direction of the transmitting antenna during the transmission period, and the receiving antenna adopts omnidirectional receiving mode during the idle period.

[0016] Furthermore, the specific implementation of step (4) is as follows:

[0017] 4.1 Calculate the current channel busy rate (CBR) by monitoring spectrum usage over a past period. pri As the actual value;

[0018] 4.2 Determine the priority of your vehicle (the faster the speed, the higher the priority) and its corresponding Channel Busyness Rate (CBR) as the demand value based on the current vehicle speed.

[0019] 4.3 Comparison with actual CBR values pri The magnitude of the demand value CBR: If CBR > CBR pri If CBR ≤ CBR, then update its own priority information in the Side Link Control Message (SCI) and set the congestion label to 1; pri If so, it updates its own priority information and sets the congestion label to 0 in the Side Link Control Message (SCI).

[0020] 4.4 Detect whether a yield request has been received from a higher-priority vehicle (i.e., a congestion label of 1 indicates this), and then calculate and determine the signal transmission power P of the vehicle in the next round of radar scanning. TX and the launch interval T rad .

[0021] Furthermore, in step 4.4, for CBR ≤ CBR pri In this case, if a yield request is received from a higher-priority vehicle, the signal transmission power P is calculated using the following formula. TX and the launch interval T rad ;

[0022] T rad =min{T rad,0 +ΔT rad T rad,MAX}

[0023] P TX =max{P TX,0 -ΔP,P TX,MIN}

[0024] If no yield request is received from a higher-priority vehicle, the signal transmission power P is determined using the following formula. TXand the launch interval T rad ;

[0025] T rad =max{T rad,0 -ΔT rad T rad,MIN}

[0026] P TX =min{P TX,0 +ΔP,P TX,MAX}

[0027] Where: P TX,0 and T rad,0 These represent the signal transmission power and transmission interval of the previous radar scan, ΔT. rad T is the step size of the transmission interval, ΔP is the step size of the signal transmission power, and T is the step size of the transmission interval. rad,MAX and T rad,MIN P represents the upper and lower limits of the launch interval. TX,MAX and P TX,MIN These are the upper and lower limits of the signal transmission power;

[0028] For CBR > CBR pri In this case, if a yield request is received from a higher-priority vehicle, the signal transmission power P is calculated using the following formula. TX and the launch interval T rad ;

[0029] T rad =min{T rad,0 +ΔT rad T rad,MAX}

[0030] P TX =max{P TX,0 -ΔP,P TX,MIN}

[0031] If no avoidance request is received from a higher priority vehicle, the signal transmission power and transmission interval of the previous radar scan will be used.

[0032] Furthermore, the specific implementation of step (5) is as follows: by listening to the spectrum usage over a period of time and based on the spectrum resources required for a single signal transmission by the vehicle, the specific time period and frequency band of each signal transmission during the next round of radar scanning by the vehicle can be calculated and determined using the SPS (Semi-sersistent scheduling) resource selection method in 5G NR V2X mode2.

[0033] Furthermore, the SPS-based resource selection method adopts a listening-then-selection approach. First, the spectrum in the environment is monitored, and resources are excluded and selected based on the signal power detected on the resource block and the information in the side link control message (SCI). The method also adds its own resource reservation information to the SCI to provide information for other vehicles to select resources.

[0034] This invention proposes a method for implementing a vehicle-to-everything (V2X) ISAC system that uses semi-permanent scheduling and divides space into sectors to complete millimeter-wave directional communication and periodic scanning of millimeter-wave radar. This method enables the simultaneous completion of radar and communication functions using the same transmitted waveform and the same hardware device, saving the spectrum and hardware resources occupied by both.

[0035] Because the signal in the millimeter-wave ISAC system is transmitted directionally and the radar function requires a large transmit power, the interference in the system is quite severe, which will have a significant impact on the performance of both radar and communication. This invention proposes an antenna usage method for the ISAC system, which uses two independent array antennas as transmitting and receiving antennas respectively. During system operation, the transmitting and receiving array antennas are controlled to change the transmission and reception time and direction as needed, thereby reducing the interference to the vehicle while minimizing the impact on radar and communication performance and spectrum monitoring, thus improving system performance.

[0036] To support radar functionality in 5G NR V2X systems, this invention proposes a resource selection method for vehicle-to-everything (V2X) ISAC systems. The method re-divides resource blocks to meet radar resolution requirements and adopts a 5G NR V2X mode 2-based "listen-then-select" approach. First, the spectrum in the environment is monitored. Based on the signal power detected on the resource blocks and information from the Sidelink Control Information (SCI), resource exclusion and selection are performed. Furthermore, the method incorporates its own resource reservation information into the SCI to provide information for other vehicles in resource selection.

[0037] This invention classifies vehicles into different priorities based on speed and incorporates additional control information into the SCI (Speed ​​Component Index) during resource selection. If the spectrum demand of a high-priority vehicle cannot be met, the congestion situation is communicated through this additional control information, requiring low-priority vehicles to adjust their radar scanning cycle and transmit power to avoid the vehicle. Based on the above technical solution, this invention has the following beneficial technical effects:

[0038] 1. In order to realize the vehicle-to-everything (V2X) ISAC system, this invention considers using Orthogonal Frequency Division Multiplexing (OFDM) signals as an integrated waveform to simultaneously complete radar and communication functions. It adopts a sector division and periodic scanning working mode and uses two independent array antennas for integrated signal transmission and reception. This can realize the use of the same waveform and equipment to simultaneously complete radar and communication functions, reducing the use of spectrum resources.

[0039] 2. In order to allocate spectrum resources that meet the radar and communication requirements of each vehicle in the ISAC system, this invention re-divides the resource blocks of the 5G NR V2X mode 2 protocol, adopts a listening-then-selection method for resource selection, and notifies other vehicles of the resource reservation status. While minimizing spectrum conflicts, it selects resource blocks that meet the requirements, enabling the coexistence of vehicles with integrated sensing and communication functions and vehicles with only communication functions operating under 5G NR V2X while the integrated sensing and communication vehicle completes the resource selection.

[0040] 3. To alleviate spectrum conflicts in the vehicle-to-everything (V2X) ISAC system, this invention divides vehicles into different priorities based on speed and enables the transmission of congestion information between vehicles by adding additional control information to the SCI. By adjusting the transmission parameters, the spectrum usage of vehicles is automatically adjusted, which can ensure that high-priority vehicles have priority in using spectrum resources when spectrum resources are scarce, thereby improving the overall performance of the ISAC system. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the vehicle radar detection sector division according to the present invention.

[0042] Figure 2 This is a schematic diagram illustrating the usage of the transmitting and receiving antennas of the present invention.

[0043] Figure 3 This is a schematic diagram of the resource selection method of the present invention.

[0044] Figure 4 This is a schematic diagram illustrating the workflow of the congestion control method of the present invention.

[0045] Figure 5 This diagram illustrates a comparison of the communication performance of the method of this invention with other resource allocation methods.

[0046] Figure 6 This diagram illustrates a comparison of radar performance between the method of this invention and other resource allocation methods. Detailed Implementation

[0047] To describe the present invention in more detail, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] (1) In order to achieve integrated communication and sensing in the Internet of Vehicles, the user vehicle in this invention needs to be equipped with independent transmitting array antennas and receiving array antennas on the roof, and the transmitted signal is an integrated communication and radar signal carried by OFDM. Figure 1 As shown, this invention uniformly divides the radar detection area into L sectors. The radar function transmits an integrated signal for target detection within one sector at a time, and performs radar detection on each sector sequentially. The detection time for each sector is T. sect One radar scan is completed once all sectors have been detected; the time interval between the start of two adjacent radar scans is one radar detection period T. rad Adjustments can be made based on vehicle priority and channel congestion status, but T should be guaranteed. rad ≥L×T sect .

[0049] For communication functions, this invention proposes two modes: unicast and broadcast, such as... Figure 1 As shown, in unicast mode, communication and radar use two different beams. While performing radar detection within one sector, an additional signal is transmitted to the sector containing the communication target for unicast communication. The radar beam power accounts for α of the total transmitted power, and the communication beam power accounts for 1-α of the total transmitted power, thus enabling the same equipment to perform both radar and communication functions within a single time slot. In broadcast mode, communication and radar use the same main lobe to simultaneously perform radar detection and information transmission within the same sector, completing one radar scan while simultaneously broadcasting information omnidirectionally.

[0050] (2) In the 5G NR V2X mode 2 protocol, the resource allocation method only considers the communication function. A single antenna is used for signal transmission and reception to achieve half-duplex communication, and signal reception is not performed during signal transmission. However, in the vehicle-to-everything (V2X) ISAC system to which this invention applies, millimeter-wave frequency bands are required for directional transmission. Furthermore, considering that radar detection targets in a V2X environment are typically within a small range (e.g., 200m), radar echo reception must be performed within the duration of radar signal transmission. If the aforementioned single-antenna half-duplex method is used, radar signal transmission and reception cannot be completed. To ensure that the reception function is not affected during signal transmission, this invention uses two independent phased array antennas as the transmitting and receiving antennas, respectively.

[0051] Because millimeter-wave radar requires significantly higher transmission power than communication equipment and employs directional transmission, the interference power between vehicles in an ISAC (Important Information Center) vehicle-to-everything (V2X) system is much stronger than in a V2X system that only performs communication. The omnidirectional receiving method results in interference from all directions, severely impacting the performance of both radar and communication. Therefore, the receiving antenna configuration will be adjusted as needed, such as... Figure 2 As shown, during the integrated signal transmission process, the receiving antenna becomes directional, with its direction being the same as the radar's main lobe transmission direction; when the transmitting antenna is idle, the receiving antenna will be in omnidirectional receiving mode, used for receiving communication signals and spectrum monitoring.

[0052] (3) Unlike the 5G NR V2X mode 2 protocol, the MAC protocol of this invention needs to serve both radar and communication simultaneously. Therefore, when allocating spectrum resources, it is necessary to redefine resource blocks according to radar requirements to ensure that the range resolution ΔR and velocity resolution Δv of radar scanning meet the actual requirements. Specifically, based on the OFDM radar range detection algorithm proposed in the literature "Range estimation of CE-OFDM for radar-communication Integration" (author X.Li, published in IEEE ICCS 2018, Jun. 2018, pp. 131-135), the bandwidth B occupied by the radar signal is determined by the radar range resolution ΔR, satisfying:

[0053]

[0054] Where: c is the speed of light; in order to ensure that the signal transmission bandwidth of the ISAC system meets the range resolution requirements, the bandwidth of the resource block in the MAC protocol of this invention is set to be the same as the bandwidth B required to meet the range resolution ΔR; when selecting resources, selecting a single resource in the frequency domain can meet the bandwidth requirements of the radar signal.

[0055] This invention is based on the OFDM radar velocity detection algorithm proposed in the literature "2D radar imaging with velocity estimation using a MIMOOFDM-based radar for automotive applications" (author YLSit, published in EuRAD 2013, Oct. 2013, pp. 145-148), where the number of OFDM symbols N used for radar detection is... symbol Determined by the velocity resolution Δv, it satisfies:

[0056]

[0057] Where: f c T is the carrier frequency. OFDM The time length is for a single OFDM symbol. In 5G NR V2X mode 2, the time length of a resource block is specified as a time slot. To be compatible with this, this invention selects resources with N in the time domain. symbol Multiple consecutive resource blocks of OFDM symbols are used to meet the time length requirements of radar signals.

[0058] (4) In order to be compatible with 5G NR V2X communication system, this invention refers to the SPS-based resource selection method in 5G NR V2X mode2. That is, the user equipment first listens to the signals in the surrounding environment to obtain the wireless resource usage in the surrounding environment, and then selects the resources to be used according to the listened resource usage information. At the same time, it reserves resources for all subsequent scan sectors and announces the reserved information in SCI to reduce spectrum conflicts and interference with other vehicles.

[0059] like Figure 3 As shown, assuming a user vehicle begins resource selection at time n, it first needs to determine a listening window and a selection window in the resource pool. Based on the listening information on the resource blocks within the listening window, the desired resource is selected within the selection window. The time range of the listening window is [n-T0, nT]. proc,0 ), where n-T0 is the start time of the listening window, and T proc,0 This refers to the time required to complete the sensing information processing process; the time range of the selection window is [n+T1, n+T2], where T1 is the number of processing time slots required for the user equipment to complete the resource selection process, T2 is the maximum time range of the selectable resources, and the values ​​of T0 and T2 are selected within the range specified by the mode 2 protocol. proc,0 The value of T1 is determined by the processing power of the user equipment.

[0060] After setting the monitoring window and selection window, it is necessary to obtain the Reference Signal Receiving Power (RSRP) of the resource block within the monitoring window. If the RSRP is higher than a specified threshold γ, the resource block is considered to be occupied by another vehicle; otherwise, the resource block is considered to be idle. If the resource block is occupied, the sidelink control information sent by other vehicles on that resource block will be read, which includes resource reservation information of other devices. After obtaining the resource block occupancy status and resource reservation information, the following resource exclusion and resource selection process needs to be performed within the selection window based on the obtained information:

[0061] First, resources reserved by other vehicles need to be excluded. If the RSRP of a signal received on a resource block in slot S1 of the monitoring window is higher than γ, and the Resource Reservation Interval (RRI) of the vehicle using that resource block is known in the SCI of that signal, then resources within the selection window that are equal to S1+q1×RRI need to be excluded. RX Overlapping resources, where RRI RX This refers to the RRI (Reported Requested Information) announced by other vehicles in the SCI (Search Engine Information Center). The value of q1 ranges from 1 to q1 to Q1, where Q1 represents the transmission interval of RRI. RX The estimated number of transmission cycles under the condition that RRI is simultaneously satisfied; RX <T2 and n-S1≤RRI RX Under two conditions, Q1 equals Otherwise, Q1 is 1.

[0062] Furthermore, it is necessary to exclude resource reservations that might be ignored by user vehicles during their use of resource blocks. If the S2 time slot in the monitoring window is a resource block previously used by a user vehicle, since the vehicle transmitted an integrated signal on the S2 time slot, it is known from the antenna setting method of this invention that monitoring cannot be performed in this time slot. Therefore, the resource reservation information of other vehicles existing on S2 may be ignored. To minimize resource conflicts as much as possible, S2+q2×RRI needs to be excluded. x All candidate resources for the corresponding time slot, where RRI x Let q2 be the set of all allowed RRI values ​​in the current system, where q2 ranges from 1 to q2, and Q2 represents the value of the transmission interval which may be RRI. x For each value in the given condition, the estimated number of transmission cycles is calculated when RRI is simultaneously satisfied. x <T2 and n-S2≤RRI x Under two conditions, Q2 equals Otherwise, Q2 is 1.

[0063] After the above two elimination steps, it is necessary to check whether the remaining candidate resource blocks are greater than or equal to X% of the total number of resource blocks, and whether there are contiguous resource blocks that meet the radar range resolution and velocity resolution requirements. If the remaining candidate resources do not meet the conditions, the RSRP threshold needs to be increased by 3dB to increase the number of available resource blocks; if the remaining candidate resources meet the conditions, a resource block that can meet the requirements of the ISAC system is randomly selected from all candidate resources. In order to achieve periodic radar scanning and be compatible with the 5G NR mode 2 protocol, this invention adopts the SPS method for resource reservation. After determining the time-frequency resources to be used, the vehicle sets the value of the reselection counter to the number of sectors L. After completing a radar scan of a sector, the reselection counter is decremented by 1. When the reselection counter reaches zero, it indicates that a radar scan has been completed. At this time, the vehicle has a probability r of deciding to reselect resources at the start of the next radar scan; otherwise, it will continue to use the previously selected resources.

[0064] To facilitate the exchange of control information between vehicles, in the first time slot before using the selected resources, we allow the transmitting array to operate in omnidirectional mode to broadcast the control information that needs to be announced during that scan cycle, thereby increasing the probability that other vehicles will receive the control information.

[0065] (5) To alleviate the potential spectrum congestion problem in the vehicle-to-everything (V2X) ISAC system, this invention classifies vehicle priority into three levels based on driving speed: when the speed is high, the vehicle needs more radar detection opportunities to ensure driving safety and has high priority; conversely, when the speed is low, it has low priority; and when the speed is between the two, it has medium priority. This invention adjusts the spectrum resources occupied by vehicles by adjusting the radar scan cycle and signal transmission power. When spectrum resources are sufficient, all vehicles will maintain the minimum radar scan cycle and use the maximum transmission power as much as possible; when resources are scarce, vehicles will announce the spectrum congestion situation in the control information. If a lower-priority vehicle receives the congestion control information announced by a higher-priority vehicle, it will automatically adjust its own radar scan cycle and transmission power to ensure the performance of the higher-priority vehicle in the system.

[0066] To implement the congestion control method described above, the vehicle adds additional control information to the SCI (Spectrum Controller Interface). This control information includes the vehicle's own priority field and a congestion label. The vehicle's own priority field sets its priority when selecting resources. The congestion label can be set to either 0 or 1. A value of 1 indicates spectrum congestion, requiring lower-priority vehicles to yield, while a value of 0 indicates no yielding is required. During spectrum monitoring, the vehicle acquires resource reservation information from other vehicles in the SCI, and simultaneously acquires the aforementioned control information.

[0067] In this invention, Channel Busy Rate (CBR) is used to measure spectrum congestion. When a vehicle selects resources, it first calculates the Received Signal Strength Indicator (RSSI) value SC_RSSI for each sub-channel based on the monitoring information within the monitoring window. The RSSI value of a sub-channel is equal to the average RSSI measured by the receiving device on that sub-channel across all time slots within the monitoring window, i.e.:

[0068]

[0069] Where: M is the total number of time slots within the listening window, SC_RSSI m This is the RSSI measured in the m-th time slot within the listening window. The channel busy rate (CBR) of the terminal in time slot n. n The calculation formula is as follows:

[0070]

[0071] Where: N SC_RSSI N represents the number of sub-channels in the resource pool whose RSSI exceeds the configured threshold. SC_Total This represents the total number of sub-channels in the resource pool. Vehicles with different priorities have different requirements for channel congestion rate. High-priority vehicles need to operate in an environment with a lower CBR value, while low-priority vehicles can tolerate a higher CBR value.

[0072] like Figure 4 As shown, the specific workflow of the congestion control method of the present invention is as follows:

[0073] Before selecting resources, the vehicle determines its priority based on its speed and calculates its current CBR value using spectrum monitoring information, then compares it with the CBR value corresponding to its priority. pri In comparison, to determine whether the current spectrum congestion level meets its own needs, if the needs are met, the vehicle will update its own priority field in the additional information of SCI and set the congestion label to 0; if the current CBR does not meet the requirements, the vehicle will update its own priority field and set the avoidance indication position to 1 to notify nearby vehicles to modify their transmission parameters to avoid the congestion.

[0074] Next, the vehicle will read the SCI information received in the monitoring window to check if any vehicles with higher priority are requesting to give way. If a give way request is found, the vehicle needs to adjust its radar scan cycle T. rad Increase ΔT rad and transmit power P TXReduce ΔP; if there is no avoidance requirement, the next step needs to be determined based on whether the CBR requirement was met in the previous step: if the CBR requirement is met, the vehicle will move T rad Reduce ΔT rad and P TX Increase ΔP; if the CBR requirement is not met, the vehicle will maintain its current transmission parameters. Meanwhile, this invention sets the upper and lower limits of the radar scanning period to T. rad,MAX With T rad,MIN The upper and lower limits of the transmit power are P TX,MAX With P TX,MIN When adjusting vehicle parameters, the range limit of the corresponding parameter shall not be exceeded.

[0075] After the launch parameters are determined, the vehicle uses the SPS resource selection method of the present invention to select the resources to be used, sets a reselection counter, and adds resource reservation information in SCI to announce its own resource occupancy information.

[0076] This invention redesigns the resource block size, antenna usage method, and resource selection method in the 5G NR V2X mode 2 protocol. It achieves automatic adjustment of vehicle resource usage based on spectrum congestion by prioritizing vehicles and adding additional control information. However, these adjustments do not affect the rules of the vehicle resource reservation method, and the selection of relevant parameters can be set within the limits allowed by the 5G NR V2X mode 2 protocol, without affecting the spectrum sensing and resource selection process of other vehicles using the original protocol. Therefore, vehicles using the resource selection algorithm of this invention that integrate sensing and communication can be compatible with vehicles using only the 5G NR V2X mode 2 communication protocol.

[0077] The following simulation verifies the beneficial technical effects of this invention. The simulation assumes that vehicle priorities are divided into three types, each corresponding to a different driving speed v. Different CBR requirements are set for different vehicle priorities, and the specific parameter settings are shown in Table 1:

[0078] Table 1

[0079] Priority Speed ​​(m / s) CBR requirements high v≥27.8 0.4 middle 22.2≤v＜27.8 0.6 Low v＜22.2 0.8

[0080] The simulation settings followed the highway scenario model given in the 3GPP TR36.885 document. The simulation scenario was a straight highway with three lanes in each direction, and each lane was 4 meters wide. For ease of simulation, the total length of the highway was set to 1250 meters. Vehicles were distributed across 6 lanes and all were located in the middle of the lanes. The vehicle distribution on each road followed a Poisson process with a density of λ. The vehicle motion model adopted the Intelligent Drive Model (IDM) proposed in the literature "Traffic flow dynamics: Data, models and simulation" (Springer, author M. Treiber). The vehicles always maintained straight-line motion, without considering special actions such as overtaking, stopping, and changing lanes. The vehicles adjusted their acceleration based on the distance and speed difference with the vehicle in front to prevent vehicle positions from overlapping during the simulation. The simulation waveform used was an OFDM waveform with a cyclic prefix. The relevant parameters were set according to the selectable parameter range in the 5G NR V2X protocol. The radar detection algorithm adopted the frequency domain-based target information processing algorithm proposed in Chapter 5, Section 2 of "Integrated Waveform Design for Communication Radar" (National Defense Industry Press, author Hu Su). Range and velocity information can be extracted from the frequency and time axes of the OFDM echo signal, respectively. This satisfies the multi-carrier communication requirements of the 5G NR standard while also realizing the extraction of radar detection information. The main simulation parameters are shown in Table 2.

[0081] Table 2

[0082]

[0083]

[0084] Figure 5 and Figure 6The comparison results of the proposed method with the SPS resource allocation method (without congestion control) and the time-division multiplexing resource allocation method in unicast and broadcast modes in terms of communication and radar performance are presented respectively. The average channel capacity is used as the communication performance indicator, and the radar error detection rate is used as the radar performance indicator, which is equal to the sum of the radar false alarm probability and the missed alarm probability. It can be seen that the proposed method outperforms both comparative methods in terms of communication and radar performance under different vehicle densities. Compared with the SPS method, the proposed method can achieve congestion control when spectrum resources are scarce, thus the performance improvement is more significant when vehicle density is high. Compared with the time-division multiplexing method, the proposed method uses an integrated waveform as the transmitted signal, and the radar signal is also a useful signal for the receiving vehicle, which can improve the signal-to-noise ratio of the received signal. At the same time, sharing the same spectrum resource between radar and communication, compared with the time-division multiplexing scheme where radar and communication are separate, can effectively improve spectrum utilization when spectrum resources are scarce, which helps to improve radar and communication performance. This demonstrates that the proposed integrated vehicle-to-everything (V2X) sensing solution can effectively solve the spectrum conflict problem between radar and communication equipment when available resources are scarce, and improve the overall system performance.

[0085] Furthermore, in the broadcast mode of this invention, since communication and radar functions share the same beam, a higher signal-to-noise ratio can be obtained by communicating through a radar beam with greater power, resulting in better communication performance than the unicast mode. This advantage is even more pronounced when vehicle density is high. Therefore, when the spectrum resources of the integrated solution are severely insufficient, the broadcast mode can be switched to obtain higher channel capacity.

[0086] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. Those skilled in the art can readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. A resource allocation method for a 5G NR V2X-compatible vehicle-to-everything (V2X) integrated sensing system, comprising the following steps: (1) By dividing the space into sectors, a vehicle-to-everything (V2X) communication method based on millimeter-wave directional communication and radar periodic scanning is designed; (2) Optimize the vehicle antenna and its transmission and reception directions. That is, the vehicle uses two independent phased array antennas as the transmitting antenna and the receiving antenna respectively. At the same time, during the transmission period, the direction of the receiving antenna is consistent with the direction of the transmitting antenna, and during the idle period, the receiving antenna adopts an omnidirectional receiving mode. (3) Determine the spectrum resources required for a single signal transmission by the vehicle, including duration and bandwidth; (4) Calculate and determine the signal transmission power and transmission interval for the next round of radar scanning of the vehicle. The specific implementation method is as follows: 4.1 Calculate the Channel Busy Ratio (CBR) at the current time by monitoring the spectrum usage over a past period of time pri as a real value; 4.2 Determine the priority of your vehicle and its corresponding Channel Busyness Rate (CBR) as the demand value based on the current vehicle speed. 4.3 Compare actual value CBR pri with demand value CBR size: if CBR > CBR pri , update own priority information in sidelink control message SCI and set congestion flag to 1; if CBR < CBR pri , update own priority information in sidelink control message SCI and set congestion flag to 0; 4.4 Check if a higher priority vehicle has sent an avoidance request and in turn calculate the signal transmission power P for the next radar scan of the vehicle TX and the transmission interval T rad , in particular: For CBR≤CBR pri In case, if a higher priority vehicle sends an avoidance request, the determination signal transmission power P is calculated by the following formula TX And the transmission interval T rad ; If no request for avoidance from a higher-priority vehicle is received, the signal transmission power P is determined by the following formula TX and the transmission interval T rad ; in: and Do not worry about the signal transmission power and transmission interval of the previous radar scan. The step size of the launch interval. The step size for signal transmission power. and These are the upper and lower limits for the launch interval. and These are the upper and lower limits of the signal transmission power; For CBR > CBR pri In this case, if a yield request is received from a higher-priority vehicle, the signal transmission power P is calculated using the following formula. TX and the launch interval T rad ; If no avoidance request is received from a higher priority vehicle, the signal transmission power and transmission interval of the previous radar scan will be used. (5) Calculate and determine the specific time period and frequency band of each signal transmission during the next round of radar scanning of the vehicle. The specific implementation method is as follows: by listening to the spectrum usage in the past period and based on the spectrum resources required for a single signal transmission of the vehicle, the specific time period and frequency band of each signal transmission during the next round of radar scanning of the vehicle are calculated and determined using the SPS-based resource selection method in 5G NR V2Xmode2.

2. The resource allocation method for the vehicle-to-everything (V2X) sensor-integrated system according to claim 1, characterized in that: The vehicle-to-everything (V2X) ISAC communication method based on millimeter-wave directional communication and radar periodic scanning in step (1) is as follows: the vehicle in the V2X network is required to transmit OFDM signals in the form of electromagnetic waves in the millimeter-wave band as an integrated waveform to transmit communication information and obtain radar perception information, and the communication information includes side link control messages (SCI); since the millimeter-wave band has the characteristics of high frequency, short wavelength and severe attenuation, and the vehicle is required to transmit in a directional manner, specifically: the circumference centered on the vehicle is divided into multiple sectors, and the vehicle radar transmits an integrated waveform in one sector each time to perform target detection, and the target detection is performed on each sector in turn to complete one round of radar scanning.

3. The resource allocation method for the vehicle-to-everything (V2X) sensor-integrated system according to claim 2, characterized in that: The vehicle-to-everything (V2X) ISAC communication method includes two modes: unicast and broadcast. In unicast mode, communication and radar use two different beams. That is, while radar detection is performed in one sector, an additional signal is transmitted to the other sector where the communication target is located for unicast communication. In broadcast mode, communication and radar use the same beam. That is, radar detection and information transmission are performed simultaneously in the same sector. Completing one round of radar scanning is equivalent to performing an omnidirectional broadcast of information.

4. The resource allocation method for the vehicle-to-everything (V2X) sensor integrated system according to claim 1, characterized in that: The SPS-based resource selection method adopts a listening-then-selection approach. First, the spectrum in the environment is monitored. Based on the signal power detected on the resource block and the information in the side link control message (SCI), resources are excluded and selected. The method also adds its own resource reservation information to the SCI to provide information for other vehicles to select resources.

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