Dual-frequency cooperation resource scheduling method for millimeter wave communication perception integrated Internet of Vehicles

Abstract

The invention discloses a dual-frequency cooperation resource scheduling method for a millimeter wave communication perception integrated Internet of Vehicles, which realizes a dual-beam communication perception integrated Internet of Vehicles scheme based on a frequency hopping OFDM waveform, and can realize 360-degree radar detection and point-to-point millimeter wave communication at the same time. If radar detection is triggered, time-frequency resources needed by radar signal emission are calculated according to resolution requirements, and resources are selected and reserved for current and future radar detection on an MAC layer; and if the millimeter wave communication is triggered, the communication receiver schedules resources for the current millimeter wave communication on the MAC layer through assistance of the sub-6G frequency band. The method is compatible with a 5G NR protocol, interference suffered by ISAC equipment in a network is effectively reduced, and 360-degree radar detection and reliable and high-speed millimeter wave point-to-point communication of vehicles in a dense network can also be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle networking communication, and particularly relates to a dual-frequency cooperative resource scheduling method for a millimeter-wave communication and sensing integrated vehicle networking. Background Art

[0002] Currently, autonomous vehicles rely only on the environmental information within their line of sight sensed by a variety of sensors, which is insufficient to meet the decision-making and control requirements of high-speed moving vehicles. There is also a need for vehicles to share the huge amounts of data generated by sensors, and improve the reliability of decision-making and control of autonomous vehicles through data fusion. V2X (Vehicle-to-Everything) millimeter-wave communication, due to its rich bandwidth resources, is expected to become a key technology for sharing huge amounts of sensing data between autonomous vehicles. However, the high-speed movement of vehicles causes both sides of millimeter-wave communication to consume a large amount of signaling for beam management. For this reason, ISAC (Integrated Sensing and Communication) technology is introduced to assist beam management through radar sensing to reduce signaling consumption. However, with the introduction of the sensing function, the interference problem in the V2X network becomes more complex, and relying solely on interference management at the physical layer can no longer meet the performance requirements. It is necessary to reasonably schedule wireless spectrum resources at the MAC (Medium Access Control) layer to reduce wireless spectrum conflicts.

[0003] Existing ISAC MAC layer resource scheduling methods can be divided into two categories, namely, MAC layer resource scheduling methods specifically designed for ISAC systems and ISAC MAC layer resource scheduling methods based on existing communication protocols. For example, the literature [V. Petrov, “On Unified Vehicular Communications and Radar Sensing in Millimeter-Wave and Low Terahertz Bands”, IEEE Wireless Commun., vol. 26, no. 3, pp. 146-153, Jun. 2019] proposed an ISAC MAC protocol based on CSMA (Carrier Sense Multiple Access). Vehicles send radar and communication data in a time-division manner and add a preamble before the radar frame so that it can be regarded as a data packet in CSMA-based communication, thus avoiding interference caused by spectrum conflicts. The literature [C. D. Ozkaptan, “Neighbor Discovery and MAC Protocol for Joint Automotive Radar-Communication Systems”, VTC 2021, pp. 1-6, Dec. 2021] specifically designed a neighbor discovery-based MAC protocol for ISAC systems. This protocol can establish a reliable communication link while improving radar sensing performance without a separate control link. The MAC protocols designed in the above-mentioned literature are similar to the resource scheduling method based on the existing IEEE 802.11ad protocol in the literature [P. Kumari, “IEEE 802.11ad-Based Radar: An Approach to Joint Vehicular Communication-Radar System”, IEEE Trans. Veh. Technol., vol. 67, no. 4, pp. 3012-3027, Apr. 2018]. Although these scheduling methods work in the millimeter wave band, they have poor compatibility with the existing mainstream fifth-generation mobile communication technology 5G NR (New Radio) protocol and are not easy to expand.

[0004] For the ISAC MAC layer resource scheduling method based on existing communication protocols, it is mainly built on the 5G NR V2X protocol. The literature [N. Decarli, "Performance Characterization of Joint Communication and Sensing With Beyond 5G NR-V2X Sidelink", IEEE Trans. Veh. Technol., vol. 73, no. 7, pp. 10044-10059, Jul. 2024] realizes ISAC based on the OFDM (Orthogonal Frequency Division Multiplexing) waveform of 5G NR in the sub-6G band. This ISAC implementation method can directly reuse the Mode 2 mode in the V2X sidechain for resource scheduling. The literature [S. N. Haider Shah, "Radar-Enabled Resource Allocation in 5G-V2X Sidelink Communication", IEEE ITSC 2023, pp. 1416-1421, Sep. 2023] considers the different requirements of radar and communication for wireless resources and schedules different numbers of resources for the two functions based on 5G NR Mode 2 in the sub-6G band. However, the above-mentioned literature is only based on sub-6G band communication signals, and its scarce bandwidth is difficult to meet the needs of future high-resolution sensing and high-rate communication.

[0005] In addition, the Chinese patent application with the publication number CN116709558A provides a resource allocation method for an integrated vehicle network communication and sensing system compatible with 5G NR V2X, which realizes ISAC and resource allocation based on the 5G NR waveform in the millimeter wave band. However, it still has problems such as a large amount of resources occupied by millimeter wave radar detection, high consumption of millimeter wave communication beam alignment signaling, and hidden nodes. Summary of the Invention

[0006] In view of the above, the present invention provides a dual-frequency cooperative resource scheduling method for an integrated millimeter wave communication and sensing vehicle network, which can not only schedule wireless resources for vehicle radar detection and millimeter wave communication to reduce signal interference, but also be compatible with the existing 5G NR V2X communication protocol, facilitating the deployment of the integrated system in the 5G communication network.

[0007] A dual - band collaborative resource scheduling method for millimeter - wave communication and sensing integrated vehicle - to - everything network, including: adopting dual - beam communication and sensing integrated V2X technology to enable vehicles to simultaneously achieve 360 - degree radar detection and point - to - point millimeter - wave communication, and formulating different resource scheduling schemes for radar signals and communication signals based on the 5G NR V2X Mode 2 mode: for radar signals, calculate the time - frequency resources required for radar signal transmission according to the resolution requirements, and select and reserve resources for current and future radar detections at the MAC layer; for communication signals, schedule resources for current millimeter - wave communication at the MAC layer with the assistance of the sub - 6G band.

[0008] Further, the specific implementation method of the dual - beam communication and sensing integrated V2X technology is as follows: First, make the ISAC device on the vehicle work in the millimeter - wave band and operate in full - duplex mode, and have two working modes: single - beam and dual - beam. At the same time, divide the circumference centered on the vehicle into multiple sectors. In the single - beam working mode, the ISAC device detects whether there are other vehicles around sector by sector to achieve 360 - degree radar perception. If other vehicles are detected in a certain sector and there is information to be sent to that vehicle, the ISAC device switches to the dual - beam working mode, that is, one beam is used to continue detecting the next sector, and the other beam is used to communicate with the detected vehicle.

[0009] Further, the number of the sectors is 2N, N = π / θ, where θ is the transmission beam width of the ISAC device.

[0010] Due to the high - resolution requirements of the autonomous driving scenario, the OFDM waveform will occupy a large bandwidth, which not only makes the hardware requirements more stringent, but also increases the burden on wireless resources. Preferably, the ISAC device uses a random frequency - hopping OFDM signal waveform adapted to 5G NR in the millimeter - wave band for radar detection. This waveform only occupies 20% of the OFDM signal bandwidth W determined according to the distance resolution requirements and can achieve the same distance resolution, thus reducing the occupied bandwidth, ensuring the radar resolution requirements, and improving the flexibility of resource selection.

[0011] Further, the specific implementation method of the resource scheduling scheme for radar signals is as follows:

[0012] A1. The transceiver mode of the vehicle ISAC device for radar signals is self - transmitting and self - receiving, and while transmitting radar signals in any sector, it directionally listens to the wireless spectrum in that sector.

[0013] A2. Based on the power level of the detected signal (radar signal or communication signal) and SCI (Sidelink Control Information), perform time - frequency resource exclusion based on the Mode 2 scheme.

[0014] A3. Randomly select a set of TBs (Transport Blocks) that meet the radar detection requirements from the time-frequency resources that have never been excluded for radar signal transmission, and reserve radio time-frequency resources for future radar detection in this sector.

[0015] Furthermore, in step A3, when selecting a set of TBs that meet the radar detection requirements for radar signal transmission, specifically: First, the resolution requirements need to be met. Calculate and determine the required OFDM signal bandwidth W and the number of OFDM symbols N according to the range resolution requirement and the velocity resolution requirement. s ; Then, the hopping OFDM combination requirements need to be met. Divide the baseband signal into B symbol blocks in the time domain. In the b-th symbol block, there are N b OFDM symbols (δ b time slots are required for transmission). The baseband signal consists of N s consecutive OFDM symbols with a bandwidth of w, where w = 0.2W. For the b-th symbol block, its carrier frequency f b = f l + k b w, f l is the lowest frequency point, 1 ≤ b ≤ B, B is a natural number greater than or equal to 5, and k b is any value among x1 to x5. x1 to x5 increase sequentially and the next value is 1 greater than the previous value. x1 ≥ 1, x5 ≤ P, and P = W tot / w, and W tot is the total bandwidth of the millimeter wave band of the V2X system; the carrier frequencies of all symbol blocks in the hopping OFDM combination shall not be less than 5 types. Each selected TB is a set of consecutive OFDM symbols with a bandwidth of w within 1 time slot, and the number of OFDM symbols included in the TB is less than or equal to the number of OFDM symbols included in the symbol block.

[0016] Furthermore, when triggering point-to-point millimeter-wave communication, a communication connection between vehicles needs to be established. The specific process is as follows: For any vehicle z, it emits radar signals for detection sector by sector. When a target vehicle is detected in a certain sector, vehicle z determines whether it wants to communicate with the target vehicle. If so, vehicle z sends a DCR (Direct Communication Require) signaling in the sub-6G band using the PSSCH (Physical Sidelink Shared Channel). This signaling additionally carries the relative position information between the target vehicle and vehicle z, facilitating the target vehicle to estimate the transmission beam angle of millimeter-wave communication using this information to complete beam coarse alignment. After receiving the DCR signaling, if the target vehicle needs to receive the information sent by vehicle z, it will send a DCA (Direct Communication Accept) signaling in the sub-6G band. This signaling contains the resource selection information of the communication signal. After receiving the DCA signaling, vehicle z will send multiple S-SSB (Sidelink-Synchronization Signal Block) for beam fine alignment and synchronization. After completing the above process, a millimeter-wave communication connection is established between vehicle z and the target vehicle, and vehicle z switches to the dual-beam working mode.

[0017] Furthermore, the specific implementation method of the resource scheduling scheme for communication signals is as follows:

[0018] B1. If the target vehicle establishes a millimeter-wave communication connection with a vehicle in the forward or backward sector, jump to step B2; if the target vehicle establishes a millimeter-wave communication connection with a vehicle in other lateral sectors, jump to step B3 or directly select a group of TBs that meet the requirements of the frequency-hopping OFDM combination for millimeter-wave communication.

[0019] B2. Reserve a certain amount of bandwidth of wireless resources in advance in the sub-6G band and divide it into P transmission blocks for mapping the wireless resources in the millimeter-wave band. When vehicle z emits radar signals in the forward or backward sector using the transmission block p in the millimeter-wave band, it will also broadcast an announcement signal indicating that the transmission block p in the millimeter-wave band is occupied on the transmission block p in the sub-6G band, where p ∈ {1, 2,..., P}. At the same time, use the receiving antenna of the sub-6G device to listen to the resource occupancy situation of other vehicles.

[0020] B3. The target vehicle performs time-frequency resource exclusion based on the Mode 2 scheme according to the power level and SCI of the detected announcement signal.

[0021] B4. Select a group of TBs that meet the communication rate requirements from the non-excluded time-frequency resources for communication signal transmission.

[0022] B5. The target vehicle transmits the selected resource information (i.e., the resource selection information of the communication signal) to vehicle z through the DCA signaling, and vehicle z sends a communication signal to the target vehicle according to the specified resource information.

[0023] A computer device includes a memory and a processor. A computer program is stored in the memory, and the processor is configured to execute the computer program to implement the above-mentioned dual-frequency cooperative resource scheduling method for the millimeter-wave communication and sensing integrated vehicle network.

[0024] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the above-mentioned dual-frequency cooperative resource scheduling method for the millimeter-wave communication and sensing integrated vehicle network.

[0025] Based on the existing 5G millimeter-wave side-chain communication, the present invention realizes 360-degree radar sensing and point-to-point millimeter-wave communication, and has a dual-frequency cooperative resource scheduling method compatible with the traditional 5G NR MAC protocol to reasonably schedule radio resources for ISAC signals, effectively reducing the interference suffered by ISAC devices in the network, enabling vehicles in a dense network to also achieve high-precision radar detection and reliable high-speed millimeter-wave point-to-point communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the working mode of the vehicle ISAC device in the present invention.

[0027] Figure 2 It is a schematic diagram of the ISAC millimeter-wave radar signal resource selection based on V2X Mode 2 in the present invention.

[0028] Figure 3 It is a schematic diagram of the generation of the frequency-hopping OFDM radar signal in the present invention.

[0029] Figure 4 It is a schematic diagram of the process of initial access and connection establishment of the millimeter-wave communication of the ISAC device in the present invention.

[0030] Figure 5 It is a schematic diagram of the ISAC millimeter-wave communication signal resource selection based on V2X Mode 2 in the present invention.

[0031] Figure 6 It is a schematic diagram of the relationship between the successful detection probability of the radar performance and the radar SINR (Signal to Interference plus Noise Ratio) threshold in the present invention.

[0032] Figure 7This is a schematic diagram showing the relationship between the communication performance (communication coverage probability) and the communication SINR threshold of the present invention. Detailed implementation manners

[0033] To describe the present invention more specifically, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0034] Embodiment

[0035] In this embodiment, each vehicle is equipped with a millimeter-wave ISAC device and a sub-6G communication device. The ISAC device consists of four array antennas, which are respectively installed around the vehicle and share a set of radio frequency links and baseband processing components to achieve full duplex. As Figure 1 shown, the device has two working modes: single-beam mode and dual-beam mode. Let the transmission beam width of the ISAC device be θ. For a 360-degree radar, it can be divided into 2N (N = π / θ) sectors, and the sectors are numbered from 1 to 2N in the counterclockwise direction starting from the front sector. In the single-beam mode, the vehicle sequentially transmits frequency-hopping OFDM signals in each sector to detect whether there are other vehicles around, so as to achieve 360-degree radar perception; if other vehicles are detected in a certain sector and there is information to be sent to that vehicle, the working mode switches to the dual-beam mode, that is, one beam is used to continue detecting the next sector, and the other beam is used to communicate with the detected vehicle.

[0036] The Sub-6G device consists of an omnidirectional transmitting antenna and an omnidirectional receiving antenna, which are installed on the vehicle roof and used to assist in resource selection in the millimeter-wave band. While the ISAC device transmits millimeter-wave radar signals in sector i = 1 (or N + 1), the Sub-6G device will omnidirectionally announce the spectrum occupancy of the ISAC device in a specific Sub-6G band, and the other receiving antenna is always omnidirectionally sensing the wireless spectrum occupancy of other vehicles. It should be noted that if the vehicle omnidirectionally announces in the corresponding Sub-6G band when transmitting radar signals in any sector, it will cause the received SCI to be unable to be decoded due to excessive interference during spectrum sensing, thus rendering the scheduling scheme ineffective. Therefore, based on the analysis of the communication performance under random allocation in the literature [L.Wang, "Performance Analysis and Optimization of ISAC Vehicular Networks with 360° Radar Detection", IEEE ICCC 2024, pp.580 - 585, Sep. 2024], it can be seen that the lateral communication performance can still exhibit good performance even under very harsh channel conditions, while the forward and backward communications are not the case. So this embodiment mainly considers the forward and backward communication to design the resource scheduling scheme, and the lateral communication can use the ordinary Mode 2 resource scheduling scheme or directly adopt the random spectrum access scheme. In addition, since the millimeter-wave radar signal is a periodic signal and the millimeter-wave communication signal is an aperiodic signal, while the ISAC device transmits millimeter-wave radar signals in sector i = 1 (or N + 1), the Sub-6G device will omnidirectionally announce the spectrum occupancy of the ISAC device in a specific Sub-6G band.

[0037] For the ISAC device, when using the OFDM waveform for radar detection, the achievable range resolution Among them, c is the speed of light, W is the bandwidth required to meet the radar resolution requirement, and it is also the bandwidth of the OFDM signal. Due to the high-resolution requirements of the autonomous driving scenario, the OFDM waveform will occupy a large bandwidth, which not only makes the hardware requirements more stringent, but also increases the burden on wireless resources. Therefore, in the millimeter wave band, the random frequency hopping OFDM signal waveform is adopted in this embodiment. The literature [C. Knill, "High Range and Doppler Resolution by Application of Compressed Sensing Using Low Baseband Bandwidth OFDM Radar", IEEE Trans. Microw. Theory Tech., vol. 66, no. 7, pp. 3535-3546, Jul. 2018] shows that this method only occupies 20% of the required bandwidth W, denoted as w = 0.2W, and can achieve the same range resolution as the OFDM signal with a bandwidth of W. The ISAC device adopts a frequency hopping OFDM waveform adapted to 5G NR, which not only reduces the occupied bandwidth, but also ensures the radar resolution requirement and improves the flexibility of resource selection. For sub-6G devices, in this embodiment, the OFDM signal specified by the 5G NR protocol is used to map and announce the millimeter wave band frequency hopping OFDM radar signal.

[0038] Due to the different characteristics of radar signals and communication signals, in this embodiment, different resource scheduling schemes are formulated for the two types of signals based on 5G NR V2X Mode 2, which together constitute a dual-frequency cooperative resource scheduling method for millimeter wave ISAC V2X. The following describes the specific implementation method for scheduling resources for millimeter wave radar signals.

[0039] V2X SL (Sidelink) Mode 2 provides two resource scheduling methods: dynamic scheduling and semi-permanent scheduling. Dynamic scheduling only selects resources for the current data transmission, while semi-permanent scheduling selects and reserves N RC groups of transport blocks, where N RC is the value of the reselection counter determined by the RRI (Resource Reservation Interval). Since the vehicle needs to continuously and periodically sense the surrounding environment, using dynamic scheduling will result in huge signaling overhead; to save this overhead, the millimeter wave radar signal should adopt the semi-permanent scheduling scheme in Mode 2. Since the interference situation in each sector is different, in this embodiment, N RC resources are separately selected and reserved for the radar detection signal in each sector. Then the resource reservation interval RRI is the time 2NT s required for the ISAC device to complete one week of detection, where Ts is the time spent detecting in each sector; when the vehicle's ISAC device completes a radar detection in sector i, the reselection counter is decremented by 1, and resources are reselected until the reselection counter reaches 0. It should be noted that in the original NR SL Mode 2, when the reselection counter is decremented to 0, there is a probability of (1 - P RC ) to reselect resources and a probability of P RC to continue using the old resources; however, due to the high-speed mobility of the vehicle, after the vehicle has passed through 2NT s duration, the surrounding channel environment may change significantly. Therefore, this scheduling method no longer follows the original scheme of reselecting resources according to the probability (1 - P RC ), but directly reselects resources.

[0040] For radar signals, as Figure 2 shown, when the vehicle triggers resource selection at time slot t, the vehicle first needs to exclude the resources in the selection window based on the occupancy of millimeter-wave band wireless resources sensed within its sensing window [t - T0, t - T proc,0 , where T0 is a preconfigured parameter of the sensing window and T proc,0 is the time required to complete the sensing process, both of which are consistent with the settings in the 3GPP protocol. Due to the full-duplex working mode of the ISAC device, the vehicle can receive signals in sector i while transmitting radar signals in sector i, so that the occupancy of resources in this sector can be directionally sensed. Therefore, the radar signal transmission sector uses millimeter-wave directionality to sense the occupancy of wireless resources of other vehicles. In this embodiment, the sensing window is basically the same as the sensing window described in 5G NR. The difference is that in the sensing window of this scheme, the solid-line box and the dashed-line box respectively represent the occupancy of wireless resources of other vehicles sensed by the vehicle in sector i and sector i - 1, which are respectively used for resource exclusion in their respective sectors, rather than all time slots in the sensing window described in V2X SL Mode 2 being available for excluding resources that may be occupied in the selection window. For the selection window [t + T1, t + T2], its window parameter T1 is consistent with the 3GPP setting; the time T2 left for the vehicle to perform transmission is updated to T 2,min ≤T2≤D ISAC , where D ISAC is the maximum delay that the ISAC device can tolerate, that is, the residence time of the ISAC device in a sector, and T 2,min is a preconfigured parameter, the same as the 3GPP configuration; in addition, if the situation of T 2,min ≥D ISAC occurs, then let T 2,min =D ISAC .

[0041] Similar to V2X SL Mode 2, the process by which a vehicle selects wireless resources for millimeter-wave radar signals transmitted in sector i can be summarized into two steps, namely resource exclusion and random selection:

[0042] Step 1: Exclude candidate resources in the selection window. At time slot t of the sensing window, if a vehicle receives a millimeter-wave signal in sector i, the first-stage SCI in its physical side-link control channel can be decoded, and the RSRP (Reference Signal Received Power) of the PSSCH channel associated with the first-stage SCI is higher than a preset threshold, then it indicates that this signal may have reserved a resource at time slot t s + τRRI. Thus, the resources of time slot t s + τRRI in the selection window can be excluded, where τ is an integer and 1 ≤ τ ≤ τ s , when RRI < T2 and t - t m ≤ RRI, s otherwise τ = 1. m

[0043] Step 2: Randomly select resources from the remaining candidate resources for information transmission. After the above exclusion, check whether the proportion of the remaining available candidate resources in all resources of the selection window is greater than or equal to X% and whether a set of TBs that meet the radar detection requirements can be selected. If satisfied, randomly select a set of TBs that meet the requirements of frequency-hopping OFDM radar detection from the candidate resources and reserve (N RC -1) sets of TBs; if not satisfied, increase the RSRP threshold by 3 dB and repeat the above steps until the selection conditions are met.

[0044] The requirements for frequency-hopping OFDM radar detection can be summarized into two points: The first is the resolution requirement, that is, the range resolution requirement Δr and the velocity resolution requirement Δv. According to Δr = c / (2N c Δf) and Δv = c / (2N s T OFDM f c ), the required bandwidth W = N c Δf and the number of OFDM symbols N s can be calculated, where c is the speed of light, N c is the number of OFDM subcarriers, Δf is the subcarrier spacing, T OFDM is the duration of the OFDM symbol, and f c is the center frequency. The second is the frequency-hopping combination requirement. As shown in Figure 3 , in the time domain, the baseband signal is divided into B symbol blocks, and there are N b OFDM symbols in the b-th symbol block (δ is required during transmission btime slots), and the baseband signal is composed of consecutive OFDM symbols with a bandwidth of w, where w = 0.2W; for the b-th symbol block, its carrier frequency f b = f l + k b w, f l is the lowest frequency point, 1 ≤ b ≤ B, where B is a natural number greater than or equal to 5 (in Figure 3 the embodiment, for ease of description, the symbol blocks are evenly divided, but they can also be divided unevenly during actual operation), k b is any value among x1 to x5, x1 to x5 increase sequentially and the latter value is 1 greater than the previous value, x1 ≥ 1, x5 ≤ P, P = W tot / w, W tot is the total bandwidth of the millimeter-wave band of the V2X system; the carrier frequencies of all symbol blocks in the frequency-hopping OFDM combination shall not be less than 5. The selected 1 TB is a group of consecutive OFDM symbols with a bandwidth of w within 1 time slot, and the number of OFDM symbols included in 1 TB is less than or equal to the number of OFDM symbols included in 1 symbol block.

[0045] The process of triggering millimeter-wave communication and establishing a connection is as Figure 4 shown: First, the vehicle emits radar signals for detection sector by sector. When it detects a target vehicle in sector i ∈ {1, 2, …, 2N}, the vehicle determines whether it wants to communicate with the target vehicle. If communication is needed, the vehicle sends DCR signaling using PSSCH in the sub-6G band, which additionally carries the relative position information between the target vehicle and itself, so that the target vehicle can use this information to estimate the transmission beam angle of millimeter-wave communication and complete beam coarse alignment. After receiving the DCR, if the target vehicle needs to receive the information sent by the vehicle, it will send DCA signaling in the sub-6G, which includes the resource selection information of the millimeter-wave communication signal; after receiving the DCA, the vehicle will first send N SSB S-SSBs for beam fine alignment and synchronization. After completing the above process, millimeter-wave side-chain communication is established between the vehicle and the target vehicle, and the vehicle switches to the dual-beam mode, one beam for detecting the next sector and the other beam for sending communication signals in the original sector.

[0046] Regarding the millimeter-wave communication signal transmitted by this vehicle, first of all, it should be noted that due to the rapid movement of the vehicle, the channel conditions experienced by the communication signal are different, and the communication signal can be a non-periodic signal. Therefore, in this embodiment, NR SL Mode 2-based dynamic scheduling of millimeter-wave communication resources is adopted. Secondly, different from the radar echo signal, the millimeter-wave communication signal is received not at its own location but at other vehicles. Therefore, to avoid the hidden node problem, the most direct method is for the receiving vehicle to directionally sense the spectrum resources occupied by other vehicles. However, since the receiving vehicle cannot predict at what time and in what direction other vehicles will transmit millimeter-wave communication signals, it is difficult to pre-perceive the wireless resource occupancy of other vehicles in the sensing window.

[0047] To solve the above problems, this embodiment proposes to use sub-6G communication to assist in the selection of millimeter-wave communication resources. Specifically: The bandwidth of the millimeter-wave band of the ISAC wireless network is W tot , which is orthogonally divided into P time blocks (TBs) each with a bandwidth of w. Then we reserve in advance in sub-6G a resource with a bandwidth of W s , which is also orthogonally divided into P time blocks with a bandwidth of w s to map the wireless resources in the millimeter-wave band. When the vehicle transmits radar signals in the forward or backward sector using the millimeter-wave band transmission block p ∈ {1, 2, …, P}, it will also send a sub-6G communication signal omnidirectionally in the corresponding sub-6G transmission block p to announce the occupancy of the millimeter-wave transmission block p, and at the same time use the sub-6G receiving antenna to monitor the occupancy of resources of other vehicles. In this way, the millimeter-wave communication receiver can sense the millimeter-wave resource occupancy of other vehicles at all times in the sub-6G band and assist the millimeter-wave communication transmitter in resource selection. In addition, since the subcarrier spacing (SCS) of the sub-6G band is smaller than that of the millimeter-wave band, the duration of one time slot in sub-6G is longer than that in the millimeter-wave band, which will lead to a situation where the time granularity of the two bands is misaligned. To align the time granularity, we adopt the mini-slot technology in 5G NR, that is, the vehicle only sends partial symbols in one time slot of the sub-6G band to realize the announcement of millimeter-wave resource occupancy.

[0048] As Figure 5 shown, the process of the millimeter-wave communication receiving vehicle scheduling wireless resources for the millimeter-wave communication signal transmitted by the millimeter-wave communication transmitter in sector i = 1 (or N + 1) can be summarized into three steps, namely resource exclusion, random selection, and information transfer:

[0049] Step 1: Assist in excluding candidate resources in the selection window through sub-6G signals. At time t in the sensing window sTime slot. If a vehicle receives a sub-6G announcement signal, the first-stage SCI can be decoded, and the RSRP value of the channel related to the first-stage SCI is higher than a preset threshold, then the time slot t can be known through signal mapping s +τRRI may reserve a resource in the millimeter wave band, then exclude the resource of the time slot t within the selection window s +τRRI time slot.

[0050] Step 2: Select a group of TBs that meet the communication requirements for information transmission from the remaining millimeter wave candidate resources in the selection window. After the above exclusion, check whether the proportion of the remaining available candidate resources in all resources of the selection window is greater than or equal to X% and whether a group of TBs that meet the communication requirements can be selected. If satisfied, randomly select a group of TBs that meet the communication rate requirements from the candidate resources; if not satisfied, increase the RSRP threshold by 3 dB and repeat Step 1 until the selection conditions are met.

[0051] Step 3: Transmit the selected resource block information to the millimeter wave communication transmitting vehicle through the DCA signal.

[0052] Verification example

[0053] Next, we verify the beneficial technical effects of the present invention through simulation. Considering a two-way two-lane scenario with a lane length of 10 km and a width of 10 m, we model the vehicle positions on each road as a 1D-MHCP (One Dimensional-Matérn Hard-Core Process) with a density of λ h The 1D-MHCP is generated by a 1D-PPP (One Dimensional-Poisson Point Process) with a density of λ p = 0.1 vehicle / m. The relationship between the two densities is λ h = [1 - exp(-2λ p d h )] / 2d h , where d h is the hard core distance, that is, the minimum distance between two vehicles. We set λ p to 0.1 vehicle / m, d h to 10 m, the vehicle speed is 60 km / h, and the Monte Carlo simulation of this scenario is repeated 5000 times.

[0054] For the ISAC device of the vehicle, its total transmission power is P t is 10 W (the radar signal transmission power P r = 8 W and the communication signal transmission power P c= 2W components), operating at 28 GHz, with 8 array transceiver antennas each, the main lobe width of the signal θ = 15 degrees, the main lobe beam gain of the array transceiver antennas is 16 each, and assuming perfect self-interference cancellation technology. The subcarrier spacing Δf of the OFDM signal transmitted by the ISAC device is 120 kHz, and the distance resolution requirement Δr sensed by the ISAC device is 1 m, then it can be calculated that w = 40 MHz is required to meet this resolution; the speed resolution requirement Δv sensed by the ISAC device is 1.5 m / s, then N s = 400 OFDM symbols, that is, N in the 5G NR system sf = 4 subframes. When the ISAC device performs spectrum resource sensing in the sensing window, its RSRP threshold γ RSRP is -125 dBm, and the sensing window parameters T0 and T proc,0 are 1100 ms and 4 time slots respectively; the selection window parameters T1 and T2 are 17 and 80 time slots respectively, and the remaining candidate resource occupancy threshold X is set to 0.2; for a system with a total bandwidth W tot = 200 MHz, if the radar detection and millimeter-wave communication select resources in a fixed frequency hopping manner, then there are (W / w)[(T2 - T1 + 1) / (8N sf )] = 10 groups of TBs available for vehicle users to choose. The ISAC device stays in a sector for 100 time slots, then when the sector size is θ = 15 degrees, it takes 0.3 s to scan a full circle, that is, the value of RRI, and further it can be known that the value range of the reselection counter is [5, 15]. It should be noted that excluding the 64 time slots occupied by the selection window, the remaining 36 time slots are sufficient to meet the time required for operations such as waiting for radar echo signals or millimeter-wave communication signals, sub-6G signaling interaction, beam alignment and synchronization, etc.

[0055] For the vehicle's sub-6G communication device, its transmit power is is 23 dBm, the transceiver antenna gains are both 2, operating at 5.9 GHz, the subcarrier spacing of the OFDM signal it transmits is 30 kHz, and the communication signal it transmits is used to announce the resource occupancy of the corresponding millimeter-wave band. Assuming that a sub-6G announcement signal includes 120 subcarriers in the frequency domain and occupies w sWith a bandwidth of 4 MHz, in order to align the time granularity with the 120 KHz sub - carriers of millimeter - wave in the time domain, the mini - slot technology is adopted, that is, one slot only contains 4 OFDM symbols. In addition, the small - scale channel is modeled as Nakagami - m model with shape parameter m. When it is a millimeter - wave signal, m = 3; when it is a sub - 6G signal, m = 1. The large - scale fading of the direct - wave signal and the reflected - wave signal channels are the same as the free - space model and the radar basic equation respectively, where the average radar cross - section is 10 dBsm. The interference only considers direct interference and single - reflection interference, and the random resource scheduling is adopted for the lateral millimeter - wave communication resource scheduling.

[0056] Figure 6 Shows the first - stage SCI decoding threshold γ SCI in different millimeter - wave frequency bands, and the relationship between radar performance and radar SINR threshold γ r . First of all, it can be seen from the figure that under the MAC - layer resource scheduling scheme proposed in the present invention, for the forward sector, its successful detection probability can reach 90% when both γ SCI and γ r are 0 dB; for the lateral sector, since the average detection distance of sector 2 is the farthest, its detection performance is the worst. Then, taking the worst - performing sector 2 as an example, its successful detection probability can reach 94% when γ r is 10 dB, which proves that the dual - beam ISAC scheme can achieve 360 - degree radar perception under the MAC - layer resource scheduling method proposed in the present invention. Secondly, under the condition of γ SCI = 0 dB, compared with the random resource scheduling scheme, the forward radar successful detection probability of the scheme proposed in the present invention is increased by up to 17%, and the lateral radar performance is increased by up to 7%.

[0057] Figure 7 Shows the relationship between communication performance and communication SINR threshold γ in different sub - 6G frequency bands under the condition of the first - stage SCI decoding threshold c . First of all, it can be seen from the figure that under the MAC - layer resource scheduling scheme proposed in the present invention, for the forward sector, its communication coverage probability can exceed 95% when and γ c = 20 dB; for the lateral sector, taking the worst - performing sector 2 as an example, its communication coverage probability can reach 95% when γ c is 30 dB, which proves that the dual - beam ISAC scheme can achieve reliable millimeter - wave communication under the MAC - layer resource scheduling method proposed in the present invention. It is worth mentioning that according to Shannon's formula, the above - mentioned phenomenon can also be explained as that under the MAC - layer resource scheduling method proposed in the present invention, when When the forward sector communication rate reaches 230.11 Mbps, the proportion of users exceeds 95%; while when the lateral sector communication rate reaches 344.47 Mbps, the proportion of users can also exceed 95%, which proves that the dual-beam ISAC scheme can achieve high-speed millimeter-wave communication under the action of the MAC layer resource scheduling method proposed in the present invention. Moreover, under the existing hardware system conditions, by setting a larger user bandwidth and system bandwidth, the communication rate can be further improved, which can be achieved in the millimeter-wave band. In addition, under the conditions of , the forward radar communication coverage probability of the scheme proposed in the present invention is at most 9% higher than that of the random resource scheduling scheme.

[0058] The above description of the embodiments is to facilitate those of ordinary skill in the art to understand and apply the present invention. It is obvious that those who are familiar with the technology in this field can easily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A dual - frequency cooperative resource scheduling method for millimeter - wave communication and sensing integrated vehicle - to - everything network, characterized in that: The dual-beam integrated sensing and communication V2X technology enables vehicles to achieve 360-degree radar detection and point-to-point millimeter-wave communication simultaneously. Based on the 5GNR V2X Mode 2 mode, different resource scheduling schemes are formulated for radar signals and communication signals: for radar signals, the time-frequency resources required for radar signal transmission are calculated according to the resolution requirements, and resources are selected and reserved for current and future radar detections at the MAC layer; for communication signals, resources are scheduled for current millimeter-wave communication at the MAC layer with the assistance of the sub-6G band.

2. The dual - frequency cooperative resource scheduling method for the millimeter - wave communication and sensing integrated vehicle - to - everything network according to claim 1, wherein: The specific implementation method of the dual-beam integrated sensing and communication V2X technology is as follows: First, the ISAC device on the vehicle operates in the millimeter-wave band and runs in full duplex, and has two operating modes: single-beam and dual-beam; at the same time, the circumference centered on the vehicle is divided into multiple sectors. In the single-beam operating mode, the ISAC device detects whether there are other vehicles around sector by sector to achieve 360-degree radar perception. If other vehicles are detected in a certain sector and there is information to be sent to the vehicle, the ISAC device switches to the dual-beam operating mode, that is, one beam is used to continue detecting the next sector, and the other beam is used to communicate with the detected vehicle.

3. The dual - frequency cooperative resource scheduling method for millimeter - wave communication and sensing integrated vehicle - to - everything network according to claim 2, wherein: The ISAC device uses a random frequency hopping OFDM signal waveform adapted to 5G NR in the millimeter-wave band for radar detection. This waveform only occupies 20% of the OFDM signal bandwidth W required according to the range resolution requirement, and can achieve the same range resolution.

4. The dual-band cooperative resource scheduling method for millimeter-wave communication and sensing integrated vehicle-to-everything network according to claim 1, wherein: The specific implementation method of the resource scheduling scheme for radar signals is as follows: A1. The transceiver mode of the vehicle ISAC device for radar signals is self-transmitting and self-receiving, and while transmitting radar signals in any sector, it directionally listens to the radio spectrum in that sector. A2. Based on the power level and SCI of the detected signal, time-frequency resource exclusion is performed based on the Mode 2 scheme. A3. A set of TBs that meet the radar detection requirements are randomly selected from the unexcluded time-frequency resources for radar signal transmission, and radio time-frequency resources are reserved for future radar detections in this sector.

5. The dual - frequency cooperative resource scheduling method for millimeter - wave communication - sensing integrated vehicle - to - everything network according to claim 4, wherein: In step A3, a group of TBs that meet the radar detection requirements are selected for radar signal transmission. Specifically: First, the resolution requirements must be met. The required OFDM signal bandwidth W and the number of OFDM symbols N are calculated and determined according to the range resolution requirement and the velocity resolution requirement. s ; Then, the FH-OFDM combination requirements are met. In the time domain, the baseband signal is divided into B symbol blocks. The b-th symbol block contains N b OFDM symbols. The baseband signal consists of N s consecutive OFDM symbols with a bandwidth of w, where w = 0.2W. W is the OFDM signal bandwidth required according to the range resolution requirement; for the b-th symbol block, its carrier frequency f b = f l + k b w, f l is the lowest frequency point, 1 ≤ b ≤ B, B is a natural number greater than or equal to 5, and k b is any value among x1 to x5. x1 to x5 increase sequentially and the latter value is 1 greater than the previous value. x1 ≥ 1, x5 ≤ P, and P = W tot / w, and W tot is the total bandwidth of the millimeter wave band of the V2X system; the carrier frequencies of all symbol blocks in the FH-OFDM combination shall not be less than 5. Each selected TB is a group of consecutive OFDM symbols with a bandwidth of w within 1 time slot, and the number of OFDM symbols included in the TB is less than or equal to the number of OFDM symbols included in the symbol block.

6. The dual - frequency collaborative resource scheduling method for millimeter - wave communication - sensing integrated vehicle - to - everything network according to claim 2, wherein: When triggering point-to-point millimeter-wave communication, a communication connection between vehicles needs to be established. The specific process is as follows: For any vehicle z, it transmits radar signals sector by sector for detection. When a target vehicle is detected in a certain sector, vehicle z determines whether it wants to communicate with the target vehicle. If so, vehicle z sends a DCR signaling using PSSCH in the sub-6G band. This signaling additionally carries the relative position information between the target vehicle and vehicle z, which is convenient for the target vehicle to estimate the transmission beam angle of millimeter-wave communication using this information to complete beam coarse alignment; after receiving the DCR signaling, if the target vehicle needs to receive the information sent by vehicle z, it will send a DCA signaling in the sub-6G band. This signaling contains the resource selection information of the communication signal; after receiving the DCA signaling, vehicle z will send multiple S-SSBs for beam fine alignment and synchronization; after completing the above process, a millimeter-wave communication connection is established between vehicle z and the target vehicle, and vehicle z switches to the dual-beam operating mode.

7. The dual - frequency cooperative resource scheduling method for millimeter - wave communication and sensing integrated vehicle - to - everything network according to claim 6, wherein: The specific implementation method of the resource scheduling scheme for communication signals is as follows: B1. If the target vehicle establishes a millimeter-wave communication connection with the vehicle in the forward or backward sector, jump to step B2; if the target vehicle establishes a millimeter-wave communication connection with the vehicle in other lateral sectors, jump to step B3 or directly select a group of TBs that meet the requirements of the frequency-hopping OFDM combination for millimeter-wave communication; B2. Reserve a certain amount of wireless resources in the sub-6G band in advance and divide them into P transmission blocks for mapping the wireless resources in the millimeter wave band, where P = W tot / w, W tot is the total bandwidth of the millimeter wave band for the V2X system, w = 0.2W, and W is the OFDM signal bandwidth required according to the distance resolution requirement; when vehicle z transmits radar signals in the forward or backward sector using transmission block p in the millimeter wave band, it will also broadcast an announcement signal indicating that transmission block p in the millimeter wave band is occupied on transmission block p in the sub-6G band, where p ∈ {1, 2,..., P}, and at the same time, use the receiving antenna of the sub-6G device to listen to the resource occupancy of other vehicles; B3. The target vehicle performs time-frequency resource exclusion based on the Mode 2 scheme according to the power level and SCI of the detected announcement signal; B4. Select a group of TBs that meet the communication rate requirements from the non-excluded time-frequency resources for communication signal transmission; B5. The target vehicle transmits the selected resource information to vehicle z through the DCA signaling, and vehicle z sends a communication signal to the target vehicle according to the specified resource information.

8. A computer device, comprising a memory and a processor, wherein a computer program is stored in the memory, and characterized in that: The processor is used to execute the computer program to implement the dual-frequency cooperative resource scheduling method for the millimeter-wave communication-aware integrated vehicle network as described in any one of claims 1 to 7.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it implements the dual-frequency cooperative resource scheduling method for the millimeter-wave communication-aware integrated vehicle network as described in any one of claims 1 to 7.

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