A communication and perception integrated system and waveform design method

Abstract

The application discloses a kind of communication and perception integrated system and waveform design method, system includes: digital signal processing module, transmitting link, receiving link, local oscillator, transmitting antenna and receiving antenna;Through system and waveform collaborative design, realize communication and perception signal waveform time-frequency multiplexing working mode, can make full use of traditional communication and perception signal simultaneously realize high-performance communication and perception, and significantly improve the real-time performance and spectrum utilization of perception and communication;Utilize the phase correlation of the proposed communication and perception integrated synthesis waveform, combined with system scheme, realize the phase noise cancellation of perception signal, eliminate the influence of phase noise, doppler effect and carrier frequency offset on communication signal, significantly improve the performance index of perception and communication baseband signal, reduce signal processing difficulty.

Description

Technical Field

[0001] This invention belongs to the fields of mobile communication and radar sensing, and particularly relates to an integrated communication and sensing system and a waveform design method. Background Technology

[0002] With the explosive growth of communication data rates, the demand for spectrum resources is increasing, and low-frequency spectrum resources are extremely scarce. Therefore, research into millimeter-wave and even terahertz frequency band technologies is an inevitable trend. Currently, millimeter-wave and terahertz frequency bands are mainly used in radar sensing systems to achieve target detection, sensing, localization, and tracking functions. Compared with communication systems, radar sensing systems share significant similarities in system architecture, both consisting of transmitters, receivers, antennas, and digital signal processing modules. Therefore, conducting research on integrated communication and sensing can not only achieve hardware resource sharing, improve system utilization, reduce overall system complexity, and realize equipment miniaturization, versatility, and multifunctionality, but also leverage the superior performance characteristics of radar sensing systems for communication, such as high transmit power, high receive sensitivity, and strong antenna directivity, all of which are beneficial to improving the performance of the communication system. In existing integrated communication and sensing technologies, one approach employs a time-sharing mode for radar sensing and communication functions, ensuring no mutual interference between the two. However, this approach suffers from low spectrum utilization and the difficulty in resolving the time allocation conflict between radar sensing and communication. Another approach utilizes complex waveform designs to achieve integrated communication and sensing, enabling simultaneous radar sensing and communication. However, this approach suffers from complex waveform design, challenging digital signal processing, and significant latency, making it difficult to simultaneously balance communication and sensing performance. As radar and communication systems operate at higher frequencies such as millimeter waves and terahertz, the impact of system phase noise becomes more pronounced, severely limiting the receiver's signal-to-noise ratio. Furthermore, the Doppler effect and communication carrier frequency offset lead to severe inter-carrier and inter-symbol interference in communication signals, limiting communication rates. Summary of the Invention

[0003] Technical Problem: To overcome the problems existing in the prior art, this invention provides an integrated communication and sensing system and waveform design method. The system simultaneously transmits and receives communication and radar sensing signals, and adopts a time-frequency multiplexing working mode. While ensuring communication and sensing performance, it significantly improves spectrum utilization and reduces signal processing difficulty; it achieves phase noise cancellation of communication and sensing signals, and eliminates the impact of Doppler effect and carrier frequency offset on communication performance.

[0004] Technical Solution: The present invention provides an integrated communication and sensing system and waveform design method. The system and waveform are designed in tandem. The system transmits a signal that is a composite signal integrating communication and sensing signals. The waveforms of the communication and sensing signals adopt a time-frequency multiplexing mode, that is, the communication and sensing signals are "simultaneous but not at the same frequency, and at the same frequency but not at the same time". The communication signal and the sensing signal use the same frequency band during the operation of the system. Within this frequency band, the frequency of the communication and sensing signals changes with time according to the design law, so as to make full use of the spectrum resources as much as possible.

[0005] The sensing signal waveforms include frequency modulated continuous wave (FMCW) signals and pulse modulated signals, and the communication signal waveforms include amplitude modulated signals, phase modulated signals, and quadrature amplitude modulated signals.

[0006] The system mainly includes: a transmitting antenna, a transmitting link, a local oscillator link, a receiving antenna, a receiving link, and a digital signal processing module. The digital signal processing module is connected to the input end of the transmitting link, the control end of the local oscillator link, and the output end of the receiving link. The transmitting link is used to synthesize the communication signal from the digital signal processing module and the sensing signal from the local oscillator link to obtain an integrated communication and sensing waveform signal, which is then radiated through the transmitting antenna. The receiving link receives the integrated communication and sensing signal through the receiving antenna. The sensing signal in the integrated signal is mixed with the local oscillator signal to obtain a sensing baseband signal containing target information. The integrated signal is then self-mixed to obtain a communication baseband signal. The sensing baseband signal and the communication baseband signal are output to the digital signal processing module.

[0007] The digital signal processing module, implemented using an FPGA or DSP, is used to generate the transmitted communication baseband signal and the local oscillator control signal, and to coordinate the control of the time-frequency relationship between the sensing signals generated by the communication and local oscillators, thereby realizing a time-frequency multiplexed integrated sensing waveform. The parameters for coordinated control include the timing, bandwidth, signal repetition period, and signal power of the communication and sensing signals. The digital signal processing module is used to process the received sensing baseband signal and communication baseband signal, and to extract the sensing information and communication information of the target distance, speed, and angle.

[0008] The transmission link includes a mixer, a filter, a combiner, and a power amplifier circuit. The mixer modulates the communication baseband signal onto a carrier wave from the local oscillator, and combines it with the sensing signal from the local oscillator according to the power relationship to obtain an integrated communication and sensing signal. The integrated signal is transmitted directly through the antenna, or it is converted to a higher frequency for transmission. The sensing signal and the communication signal adopt a time-frequency multiplexing working mode, and the two signals maintain a frequency difference to facilitate filtering and signal extraction in the receiving link. In order to ensure sensing distance and low distortion of communication signal, the power of sensing signal is higher than that of communication signal.

[0009] The receiving link includes a low-noise amplifier, a power divider, a mixer, a filter, and a combiner circuit. The mixer is divided into a sensing signal mixer and a communication signal mixer. The local oscillator signal of the sensing signal mixer is correlated with the transmitted signal. The local oscillator signal and the RF input signal of the communication signal mixer both come from the integrated sensing signal. The difference frequency signal between the communication signal and the sensing signal is obtained through self-mixing, which is the communication baseband signal.

[0010] The communication signal and the sensing signal are coherent, originating from the same local oscillator or a coherent local oscillator. For the sensing signal, the distance-dependent phase noise cancellation effect is achieved by mixing the coherent characteristics of the transmitting and receiving signals. For the communication signal, based on the system, the phase noise cancellation of the communication signal is achieved by mixing the communication signal carrier and the sensing signal (which acts as the local oscillator) in the integrated signal, eliminating the additional phase noise effects of the transmitting and receiving system and the space channel. The cancellation effect is independent of the communication distance. The communication signal mixing mechanism in the system can also eliminate the effects of Doppler frequency shift and carrier frequency offset on the communication signal.

[0011] The communication signal and the sensing signal can be transmitted and received simultaneously, and full-duplex operation can be achieved through time-frequency multiplexing, or flexibly configured as time-division multiplexing or frequency-division multiplexing.

[0012] Beneficial effects: The communication sensing integrated system and waveform design method of the present invention have the following advantages:

[0013] 1. Compared with the existing system schemes that use a time-sharing working mode for radar sensing and communication functions, the existing schemes have low spectrum utilization and the contradiction between the time allocation of radar sensing and communication is difficult to resolve. In this invention, communication and radar sensing signals are transmitted and received simultaneously through a time-frequency multiplexing working mode, which significantly improves spectrum utilization while ensuring communication and sensing performance.

[0014] 2. Compared with the existing system solutions that use complex waveform design to achieve integrated communication and sensing functions, the existing solutions have complex waveform designs, which leads to high difficulty in digital signal processing and significant mutual interference between radar sensing and communication signals. In contrast, this invention, through joint design of system solutions and waveforms and using time-frequency multiplexing, can achieve integrated communication and sensing functions using traditional communication and sensing signal waveforms, which significantly reduces the difficulty of digital signal processing and minimizes mutual interference between radar sensing and communication signals.

[0015] 3. Compared with the prior art, the integrated communication and sensing signal synthesis method proposed in this invention ensures the coherence of the carriers of the sensing signal and the communication signal. The communication and sensing receiving links use coherent mixing to cancel the additional phase noise of the radio frequency front-end system and the space channel, thereby improving the signal-to-noise ratio of the baseband output signal. The communication signal mixing scheme can also eliminate the effects of Doppler effect and carrier frequency offset. Attached Figure Description

[0016] The accompanying drawings described herein are merely illustrative of selected embodiments, not all possible implementations, and are not intended to limit the scope of this application.

[0017] Figure 1 This is a schematic diagram illustrating an application scenario of an integrated communication and sensing system provided in an embodiment of the present invention;

[0018] Figure 2 This is a block diagram illustrating the principle of an integrated communication and sensing system provided in an embodiment of the present invention.

[0019] Figure 3 This is an example of a time-frequency multiplexing waveform design for communication sensing integration based on FMCW radar signals and communication modulation signals provided by an embodiment of the present invention: (a) is the waveform of the real-time communication sensing integrated synthesized signal, (b) is the waveform of the communication sensing integrated synthesized signal with the maximum sensing signal bandwidth, (c) is the waveform of the multi-carrier communication sensing integrated synthesized signal with the maximum sensing signal bandwidth, and (d) is the spectrum relationship diagram of the baseband signal of the communication sensing integrated system.

[0020] Figure 4 This is a curve showing the change in phase noise cancellation ratio of radar sensing signals as a function of distance and offset frequency;

[0021] Figure 5 There are two communication scenarios in the integrated communication and sensing system: (a) space channel scenario and (b) relay station scenario. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0023] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. The application scenarios, system components, and waveform designs shown in the illustrations related to the present invention may be changed as needed during actual implementation and may be more complex, and are not limited thereto.

[0024] Figure 1This is a schematic diagram illustrating an application scenario of an integrated communication and sensing system provided in an embodiment of the present invention. The system is designed in conjunction with waveforms. The system transmits a signal that is a composite signal integrating communication and sensing signals. The waveforms of the communication and sensing signals adopt a time-frequency multiplexing working mode, that is, the communication and sensing signals are "simultaneous but not at the same frequency, and at the same frequency but not at the same time". The communication signal and the sensing signal use the same frequency band during the operation of the system. Within this frequency band, the frequencies of the communication and sensing signals change with time according to the design rules, making full use of spectrum resources as much as possible.

[0025] The sensing signal waveforms include frequency modulated continuous wave (FMCW) signals and pulse modulated signals, and the communication signal waveforms include amplitude modulated signals, phase modulated signals, and quadrature amplitude modulated signals.

[0026] The system mainly includes: a transmitting antenna, a transmitting link, a local oscillator link, a receiving antenna, a receiving link, and a digital signal processing module. The digital signal processing module is connected to the input end of the transmitting link, the control end of the local oscillator link, and the output end of the receiving link. The transmitting link is used to synthesize the communication signal from the digital signal processing module and the sensing signal from the local oscillator link to obtain an integrated communication and sensing waveform signal, which is then radiated through the transmitting antenna. The receiving link receives the integrated communication and sensing signal through the receiving antenna. The sensing signal in the integrated signal is mixed with the local oscillator signal to obtain a sensing baseband signal containing target information. The integrated signal is then self-mixed to obtain a communication baseband signal. The sensing baseband signal and the communication baseband signal are output to the digital signal processing module.

[0027] The communication signal and the sensing signal are coherent, originating from the same local oscillator or a coherent local oscillator. For the sensing signal, distance-dependent phase noise cancellation is achieved through mixing using the coherent characteristics of the transmitting and receiving signals. For the communication signal, based on the system, phase noise cancellation is achieved by mixing the communication signal carrier and the sensing signal (which acts as the local oscillator) using the coherent characteristics of the integrated signal, eliminating the additional phase noise effects of the transmitting and receiving system and the spatial channel. The cancellation effect is independent of the communication distance. The communication signal mixing mechanism in the system can also eliminate the effects of Doppler frequency shift and carrier frequency offset on the communication signal. The communication signal and the sensing signal can be transmitted and received simultaneously, achieving full-duplex operation through time-frequency multiplexing, or flexibly configured as time-division multiplexing or frequency-division multiplexing.

[0028] Working process: The integrated waveform signal S1 transmitted by the transmitting channel of the integrated communication and sensing system 1 is reflected by the radar sensing target. The reflected integrated waveform signal S2 is received by the receiving channel of the integrated communication and sensing system 1. The radar sensing target information is calculated by the digital signal processing module, and the communication signal in the reflected signal is filtered out. The integrated waveform signal S3 transmitted by the transmitting channel of the integrated communication and sensing system 1 is received by the receiving channel of the integrated communication and sensing system 2. The integrated communication and sensing system 2 obtains the communication signal transmitted by the integrated communication and sensing system 1 through processes such as local oscillator signal extraction, down-conversion and digital signal processing, and the radar sensing signal in the received signal is filtered out.

[0029] Figure 2 This is a block diagram illustrating the principle of an integrated communication and sensing system provided in this embodiment of the invention. The digital signal processing module includes circuits such as ADC, DAC, FPGA, and DSP, used to generate transmitted communication baseband signals and local oscillator control signals, and to coordinately control the time-frequency relationship between the sensing signals generated by the communication and local oscillator, realizing a time-frequency multiplexed integrated sensing waveform. The parameters for coordinated control include the timing sequence, bandwidth, signal repetition period, and signal power of the communication and sensing signals. The digital signal processing module is used to process the received sensing baseband signals and communication baseband signals, extracting sensing information and communication information regarding target distance, speed, and angle.

[0030] The transmission link includes circuits such as an up-converter UC, an amplifier AMP, a power combiner PC1, and a power amplifier PA. The up-converter UC modulates the communication baseband signal onto the carrier wave from the local oscillator LO, and combines it with the sensing signal from the local oscillator LO according to the power relationship to obtain an integrated communication and sensing signal. The integrated signal is transmitted directly through the antenna, or it is converted again to a higher frequency for transmission. The sensing signal and the communication signal adopt a time-frequency multiplexing working mode, and the two signals maintain a frequency difference to facilitate filtering and signal extraction in the receiving link. In order to ensure sensing distance and low distortion of communication signal, the power of sensing signal is higher than that of communication signal.

[0031] The local oscillator module of the local oscillator link is implemented using circuits such as a phase-locked loop (PLL) and a direct digital frequency synthesizer (DDS); the receiving link includes circuits such as a low-noise amplifier (LNA), a power divider (PS), an amplifier (AMP), a downconverter (DC1) for radar sensing signals, a low-pass filter (LPF), an automatic gain / level control circuit (AGC / ALC), a downconverter (DC2) for communication signals, a band-pass filter (BPF), and a power synthesizer (PC); the system also includes a transmitting antenna and a receiving antenna.

[0032] The receiving link includes a low-noise amplifier, a power divider, a mixer, a filter, and a combiner circuit. The mixer is divided into a sensing signal mixer and a communication signal mixer. The local oscillator signal of the sensing signal mixer is correlated with the transmitted signal. The local oscillator signal and the RF input signal of the communication signal mixer both come from the integrated sensing signal. The difference frequency signal between the communication signal and the sensing signal is obtained through self-mixing, which is the communication baseband signal.

[0033] Working Principle: The digital signal processing module generates the transmitted communication baseband signal and the local oscillator control signal, and coordinates the time-frequency relationship of the sensing signals generated by the communication and local oscillator to realize a time-frequency multiplexed integrated sensing waveform. The parameters for coordinated control include the timing, bandwidth, signal repetition period, and signal power of the communication and sensing signals. The digital signal processing module also processes the received sensing and communication baseband signals, extracting sensing information such as target distance, speed, and angle, as well as communication information. The transmit link up-converts the communication baseband signal and combines it with the frequency-modulated continuous wave (FMCW) radar sensing signal to form an integrated waveform signal, which is then radiated through the transmitting antenna. The receive link uses the receiving antenna to simultaneously receive the radar sensing and communication signals, and down-converts them to obtain the radar sensing baseband signal and the communication baseband signal, respectively. The local oscillator generates an FMCW signal, which serves as the radar sensing transmitted signal, the local oscillator signal of the communication transmitted link, and the local oscillator signal of the radar sensing received link. The radar sensing transmitted signal and the local oscillator signal of the radar sensing received link are coherent and have a phase noise cancellation effect, which can cancel the coherent phase noise in the signal transmission path. The cancellation ratio decreases as the radar sensing target distance increases (e.g., ...). Figure 4 (As shown); the local oscillator signal of the frequency converter under the communication signal is extracted from the received integrated communication sensing waveform signal. Space channels and relay stations have the same additional phase noise, Doppler effect, and carrier frequency offset on the communication signal and communication carrier. Utilizing the coherence between the local oscillator signal and the communication carrier signal, the additional phase noise, Doppler effect, and carrier frequency offset caused by space channels and relay stations can be eliminated (e.g., ...). Figure 5 (As shown).

[0034] Figure 3 This is an example of a waveform design method for an integrated communication and sensing system provided in an embodiment of the present invention. Figure 3 (a) to (c) are time-frequency diagrams of the radio frequency signals of the integrated communication and sensing system. The radar sensing signals all use FMCW signals, and the communication signals are signals with a certain bandwidth f. BW The modulation signal, the carrier frequency of the communication signal, and the radar sensing signal maintain a certain frequency difference f. D This is to prevent radar sensing signals and communication signals from interfering with each other. Figure 3 In (a), both the radar sensing signal and the communication signal are time-continuous, which can realize real-time radar sensing and communication functions. Figure 3(b) In this case, the radar sensing signal is continuous while the communication signal is discontinuous. The radar sensing signal can maximize the use of the system's operating bandwidth to achieve high resolution. Figure 3 (c) In order to increase Figure 3 (b) uses a multi-carrier communication method for its communication rate and bandwidth; Figure 3 (d) is a spectrum diagram of the baseband signal received by the integrated communication and sensing system, where the radar sensing baseband signal frequency f is... R Communication baseband signal frequency f Di A certain frequency protection bandwidth Δf is left between them. g To prevent mutual interference.

Claims

1. A communication and sensing integrated system, characterized in that... include: The system comprises a digital signal processing module, a transmit link, a receive link, a local oscillator link, a transmit antenna, and a receive antenna. The digital signal processing module is connected to the input of the transmit link, the control terminal of the local oscillator link, and the output of the receive link. The transmit link combines the communication signal from the digital signal processing module and the sensing signal from the local oscillator link to obtain an integrated communication-sensing waveform signal, which is then radiated through the transmit antenna. The receive link receives the integrated communication-sensing signal through the receive antenna. The sensing signal in the integrated signal is mixed with the local oscillator signal to obtain a sensing baseband signal containing target information. The integrated signal is then self-mixed to obtain the communication baseband signal. Both the sensing baseband signal and the communication baseband signal are output to the digital signal processing module. The local oscillator signal of the sensing signal mixer is coherent with the transmit signal. The local oscillator signal and the RF input signal of the communication signal mixer both originate from the integrated sensing signal. The communication signal and the sensing signal are self-mixed separately to achieve coherent phase noise cancellation.

2. The integrated communication and sensing system as described in claim 1, characterized in that: The digital signal processing module is implemented using an FPGA or DSP. It is used to generate the transmitted communication baseband signal and the local oscillator control signal, and to coordinate the time-frequency relationship between the communication and sensing signals. The parameters include timing, bandwidth, signal repetition period and signal power. It also processes the received sensing baseband signal and communication baseband signal to extract the sensing information and communication information of the target distance, speed and angle.

3. The integrated communication and sensing system as described in claim 1, characterized in that: The transmission link includes a mixer, a filter, a combiner, and a power amplifier. The mixer modulates the communication baseband signal onto the local oscillator carrier and combines it with the sensing signal according to the power relationship. The power of the sensing signal is higher than that of the communication signal to ensure sensing distance and low distortion of the communication signal. The sensing signal and the communication signal adopt a time-frequency multiplexing working mode to maintain the frequency difference, which facilitates filtering and signal extraction in the receiving link.

4. The integrated communication and sensing system as described in claim 1, characterized in that: The receiving link includes a low-noise amplifier, a power divider, a sensing signal mixer and a communication signal mixer, a filter, and a combiner; wherein, the local oscillator signal of the sensing signal mixer is correlated with the transmitted signal; the local oscillator signal and the RF input signal of the communication signal mixer both come from the integrated sensing signal, and the communication baseband signal is obtained through self-mixing.

5. The integrated communication and sensing system as described in claim 1, characterized in that: The carrier and sensing signal of the communication signal come from the same local oscillator or coherent local oscillator. For the sensing signal, the distance-dependent phase noise is canceled by mixing with the coherent characteristics of the transmit and receive signals. For the communication signal, the phase noise that is independent of the communication distance is canceled by self-mixing with the coherent characteristics of the communication carrier and sensing signal in the integrated signal, thereby eliminating the influence of the Doppler effect and carrier frequency offset on the communication signal.

6. The integrated communication and sensing system as described in claim 5, characterized in that: The communication signal and the sensing signal can be transmitted and received simultaneously, and full-duplex operation can be achieved through time-frequency multiplexing, or configured as time-division multiplexing or frequency-division multiplexing.

7. A waveform design method for a communication-sensing integrated system as described in any one of claims 1-6, characterized in that, The system architecture and waveforms are designed collaboratively to make the transmitted signal a synthesized signal integrating communication and sensing. A time-frequency multiplexing working mode is adopted, so that the communication and sensing signals are "simultaneous but not at the same frequency, and at the same frequency but not at the same time". Within the same frequency band, the frequency changes with time according to the design rules. The time-frequency relationship and power relationship of the communication and sensing signals are controlled collaboratively by the digital signal processing module. The parameters include timing, bandwidth, signal repetition period and signal power. Sensing information and communication information are extracted based on the received baseband signal.

8. The method as described in claim 7, characterized in that: The sensing signal waveforms include frequency modulated continuous wave (FMCW) signals or pulse modulated signals, while the communication signal waveforms include amplitude modulated, phase modulated, or quadrature amplitude modulated signals.

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