A concealed wireless communication method and system

Abstract

The embodiment of the present invention provides a method for sending wireless signals, including: obtaining a frequency hopping rate, an expected detection probability and a detection performance parameter of a listening end, determining a time hopping duty cycle according to the detection performance parameter, a detection threshold and an expected detection probability set based on the detection performance parameter; obtaining a frequency hopping key, generating frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generating a time hopping transmission sequence according to the time hopping duty cycle; up-converting a baseband signal according to the frequency hopping spectrum information to obtain a passband signal to be transmitted; and controlling the passband signal to be transmitted through an antenna at a specified time according to the time hopping transmission sequence. The technical solution of the embodiment of the present invention improves a certain degree of concealment by setting a frequency hopping rate, and at the same time, considering the expected detection probability that can be achieved within a reasonable parameter range and the detection performance of the listening end, the obtained time hopping duty cycle reduces the proportion of the transmitted wireless signal to further improve the concealment.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and more specifically, to a covert wireless communication method and system. Background Art

[0002] With the continuous development of wireless communication technology, more and more wireless devices have entered people's lives, bringing convenience to human life. However, with the expansion of the scope of wireless communication applications, more and more private information needs to be transmitted, such as physical health information, personal location and identity information. Due to the open space transmission characteristics of electromagnetic waves, wireless signals are easily intercepted by non-cooperative parties, resulting in private leakage and threatening user safety. In military scenarios, communication security is particularly important. Once our communication facts are detected by non-cooperative parties, it will lead to malicious attacks or information leakage by non-cooperative parties, thus changing the situation. Therefore, in order to maintain the safety of communication users, it is necessary to protect the transmission information for covert communication. For example, when the listening end interferes with the transmitted signal in the form of tracking interference, once the transmitted signal is detected, it will interfere with the transmitted signal, resulting in the interruption of the communication of the legitimate communication party. In this scenario, the sending end uses reasonable covert communication technology to make the probability of the signal being detected by the listening end as low as possible. Covert communication is also known as Low Probability Detection (LPD) communication. It hides the communication signal through reasonable technical means so that the eavesdropper cannot discover the communication facts between the two parties, thereby preventing interference or information theft.

[0003] The existing research on key technologies of covert communication mainly uses the sum of false alarm probability and missed detection probability under the energy detection algorithm as the concealment evaluation index, wherein the false alarm probability refers to the probability that the listening end judges that there is a transmitted signal under the condition that no signal is sent, and the missed detection probability refers to the probability that the listening end judges that there is no transmitted signal under the condition that the transmitting end sends a signal. Although the sum of the false alarm probability and missed detection probability under the optimal detection threshold is the lowest, the probability of false detection at the listening end can be minimized, but in actual application scenarios, since the false alarm probability is too large, the listening end will make useless work, so the listening end will adjust the detection threshold to make the false alarm probability as low as possible. In order to meet the specific false alarm probability requirements, the detection threshold set by the listening end is not the optimal detection threshold. The adjustment of the detection threshold will make the sum of the false alarm and missed detection probabilities greater than the sum of the false alarm and missed detection probabilities under the optimal detection threshold. In addition, for the transmitting end, in some specific application scenarios, the transmitting end is more concerned about the probability of the transmitted signal being detected, that is, it is hoped that the missed detection probability of the listening end is as large as possible. Therefore, the sum of the false alarm probability and the missed detection probability under the optimal detection threshold in the existing research on key technologies of covert communication cannot well describe the working mode of the monitoring end in the actual communication system.

[0004] In addition, the existing research on key technologies of covert communication can also reduce the probability of signal detection by time hopping technology. For example, the transmitter divides the transmission time into N time slots and randomly selects one of the time slots for transmission. Since the listening end cannot determine the time slot where the transmission signal is located, it needs to detect the transmission signal within a complete data transmission time slot. As the number of optional time slots increases, the uncertainty of the signal received by the listening end increases, and the capacity of the covert channel increases until all the information sent is completely covered. In the actual communication system, the energy detection algorithm used by the listening end is highly efficient and can achieve millisecond-level detection. If the time slot occupied by the transmitted data is greater than this time range, the listening end can detect the transmitted signal through multiple detections. At this time, time hopping technology cannot improve the concealment of the system. Therefore, for a fixed-frequency transmission system using time hopping technology, as the observation time of the detector increases, the detection probability of the listening end increases. Therefore, in some scenarios with a higher security level, in order to achieve the expected covert transmission requirements, the time hopping technology needs to make the transmission time slot of the transmitted signal low enough, so as to ensure that the signal power input to the detector by the listening end is less than the detection threshold.

[0005] Finally, frequency hopping technology is widely used in communication scenarios and can effectively improve the system's ability to resist fixed-frequency interference. Frequency hopping signals can reduce the probability of the transmitted signal falling into the working bandwidth of the monitoring end detector by performing frequency hopping within multiple optional frequency points, which can improve the concealment of the system to a certain extent; at the same time, as the frequency hopping rate increases, the residence time of each hopping signal at a fixed frequency point decreases, the power of the transmitted signal falling into the detector is reduced, and the concealment of the system is improved.

[0006] Based on the above analysis, it can be seen that in the existing covert communication technology, firstly, the traditional information security scheme based on encryption can only protect the transmitted signal from the perspective of calculation. With the enhancement of hardware processing power, the traditional encryption scheme based on calculation may fail and fail to effectively protect the transmitted information. Secondly, the application scenarios of the existing concealment evaluation and the actual communication system are different, resulting in the fact that the covert communication design scheme based on the existing concealment evaluation index cannot provide the best theoretical guidance for the actual covert communication system. In addition, in the actual communication system, the energy detection algorithm adopted by the monitoring end is efficient in the way of realizing covert communication through time hopping technology, and the transmitted signal can be detected in the form of multiple detections. At this time, the time hopping technology cannot improve the concealment of the system. Therefore, in order to further achieve the expected covert transmission requirements, the time hopping technology needs to make the transmission time slot of the transmitted signal low enough, and this scheme will significantly reduce the throughput of the system and cannot meet the transmission rate requirements of the communication system. Therefore, the role of time hopping technology alone in improving the concealment of the system is limited. Finally, frequency hopping technology can improve the system's ability to resist fixed-frequency interference to a certain extent. However, in actual communication systems, due to hardware limitations, the frequency hopping signal rate is limited. Therefore, the ability of frequency hopping technology alone to improve the system's concealment is also limited.

[0007] Therefore, it is necessary to improve the prior art. Summary of the invention

[0008] Therefore, the object of the present invention is to overcome the above-mentioned defects of the prior art and provide a covert wireless communication method and system.

[0009] The objective of the present invention is achieved through the following technical solutions:

[0010] According to a first aspect of the present invention, there is provided a method for sending a wireless signal, comprising: obtaining a frequency hopping rate, an expected detection probability and a detection performance parameter of a listening end, and determining a time hopping duty cycle according to the detection performance parameter, a detection threshold set based on the detection performance parameter and the expected detection probability; obtaining a frequency hopping key, generating frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generating a time hopping transmission sequence according to the time hopping duty cycle; up-converting a baseband signal according to the frequency hopping spectrum information to obtain a passband signal to be transmitted; and controlling the passband signal to be transmitted through an antenna at a specified time according to the time hopping transmission sequence.

[0011] In some embodiments of the present invention, the detection performance parameters include a received signal signal-to-noise ratio, and a method for obtaining the received signal signal-to-noise ratio includes: obtaining monitoring parameters of the monitoring end and communication parameters between the transmitting end and the receiving end; calculating the minimum transmitting signal power of the transmitting end based on the communication parameters between the transmitting end and the receiving end, and calculating the received signal signal-to-noise ratio according to the monitoring parameters and the minimum transmitting signal power.

[0012] In some embodiments of the present invention, the monitoring parameters include: a minimum monitorable distance between a monitoring end and a transmitting end, a channel fading factor, a channel noise power, a carrier wavelength, and a receiving antenna gain of the monitoring end and a transmitting antenna gain of the transmitting end; calculating a received signal signal-to-noise ratio includes: calculating the received signal power of the monitoring end according to the minimum transmitting signal power, the minimum monitorable distance, the channel fading factor, the transmitting antenna gain of the transmitting end, the receiving antenna gain of the monitoring end and the carrier wavelength; and calculating the received signal signal-to-noise ratio based on the received signal power and the channel noise power of the monitoring end.

[0013] In some embodiments of the present invention, the detection performance parameters also include a preset false alarm probability value and a detection time window length, wherein the method for determining the detection time window length includes: setting the signal sampling frequency of the listening end, obtaining the optimal detection time based on the frequency hopping rate, and determining the detection time window length according to the optimal detection time and the signal sampling frequency.

[0014] In some embodiments of the present invention, the detection threshold value set based on the detection performance parameter is set in the following manner:

[0015]

[0016] Among them, ε is the detection threshold, Q is the complementary cumulative distribution function, P f is the preset false alarm probability value, L = τf s , L is the detection time window length, the optimal detection time τ=1 / v hop , v hop is the frequency hopping rate, f s is the signal sampling frequency, is the channel noise power at the listening end.

[0017] In some embodiments of the present invention, the time hopping duty cycle is determined in the following manner:

[0018]

[0019] Where ρ is the time-hopping duty cycle, Q is the complementary cumulative distribution function, and P d is the expected detection probability, γ is the signal-to-noise ratio of the received signal at the listening end, L = τf s , L is the detection time window length, the optimal detection time τ=1 / v hop , v hop is the frequency hopping rate, f s is the signal sampling frequency, ε is the detection threshold, is the channel noise power at the listening end.

[0020] In some embodiments of the present invention, the communication parameters include: the target data transmission rate of the transmitting end and the transmitting antenna gain of the transmitting end; the minimum receiving signal-to-noise ratio of the receiving end and the receiving antenna gain of the receiving end; the distance between the transmitting end and the receiving end, the channel fading factor and the carrier wavelength.

[0021] In some embodiments of the present invention, the method for calculating the minimum transmitted signal power includes: calculating the minimum received signal power of the receiving end based on the target data transmission rate and the minimum received signal-to-noise ratio; calculating the minimum transmitted signal power based on the minimum received signal power, the distance between the transmitting end and the receiving end, the channel fading factor, the carrier wavelength, the transmitting antenna gain and the receiving antenna gain of the receiving end.

[0022] In some embodiments of the present invention, the time-hopping transmission sequence includes several time code chips indicating whether to send a passband signal; wherein, the ratio of the number of time code chips indicating that a passband signal is sent to all time code chips in the time-hopping transmission sequence conforms to the time-hopping duty cycle, and the time code chips indicating that a passband signal is sent are arranged before the time code chips indicating that a passband signal is not sent.

[0023] According to a second aspect of the present invention, a method for acquiring a wireless signal is provided, comprising: acquiring a frequency hopping rate, a frequency hopping key and a time hopping duty cycle used when sending a wireless signal according to the method provided in the first aspect of the present invention; generating frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generating a time hopping receiving sequence according to the time hopping duty cycle; controlling an antenna to receive a wireless signal at a specified time based on the time hopping receiving sequence; acquiring the received wireless signal, and down-converting the wireless signal using the frequency hopping spectrum information to obtain a baseband signal.

[0024] In some embodiments of the present invention, the time-hopping reception sequence includes a number of time code chips indicating whether a wireless signal is received, wherein the ratio of the number of time code chips indicating the reception of wireless signals to the total number of time code chips conforms to the time-hopping duty cycle, and the time code chips indicating the reception of wireless signals are arranged before the time code chips indicating that the wireless signals are not received.

[0025] According to a third aspect of the present invention, there is provided a wireless transmitting end for the method described in the first aspect of the present invention, comprising: a frequency hopping and time hopping parameter configuration module, used to obtain a frequency hopping rate, an expected detection probability and a detection performance parameter of a listening end, and determine a time hopping duty cycle according to the detection performance parameter, a detection threshold set based on the detection performance parameter and the expected detection probability; a frequency hopping and time hopping module, used to obtain a frequency hopping key, generate frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generate a time hopping transmission sequence according to the time hopping duty cycle; a first mixer, used to up-convert a baseband signal according to the frequency hopping spectrum information to obtain a bandpass signal to be transmitted; and a first high-frequency switch, used to control the bandpass signal to be transmitted through an antenna at a specified time according to the time hopping transmission sequence to obtain a wireless signal.

[0026] According to a fourth aspect of the present invention, there is provided a wireless receiving end for the method described in the second aspect of the present invention, comprising: a time-hopping and frequency-hopping parameter synchronization module, used to obtain the frequency hopping rate, frequency hopping key and time-hopping duty cycle used when sending a wireless signal according to the method described in the first aspect of the present invention; a frequency hopping and time-hopping receiving module, used to generate frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and to generate a time hopping receiving sequence according to the time hopping duty cycle; a second high-frequency switch, used to control the antenna to receive the wireless signal at a specified time based on the time hopping receiving sequence; a second mixer, used to obtain the received wireless signal, and down-convert the wireless signal using the frequency hopping spectrum information to obtain a baseband signal.

[0027] According to a fifth aspect of the present invention, there is provided a wireless communication system, comprising: the wireless transmitting end according to the third aspect of the present invention and the wireless receiving end according to the fourth aspect of the present invention.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] 1. Before sending a wireless signal, the present invention considers the expected detection probability that can be achieved within a reasonable parameter range and the detection performance of the listening end, obtains a time-hopping duty cycle, and controls the bandpass signal to be sent through the antenna at a specified time through the time-hopping transmission sequence generated by the time-hopping duty cycle, thereby reducing the proportion of the transmitted wireless signal to improve concealment, and the appropriate time-hopping duty cycle can meet the demand for data transmission rate to a certain extent. The detection performance of the detector of the listening end is limited to a certain extent by setting the frequency hopping rate. Therefore, the combination of time hopping technology and frequency hopping rate also improves the concealment during wireless communication to a greater extent.

[0030] 2. The present invention sets the detection threshold in combination with the various detection performance parameters of the listening end, improves the accuracy of the detection situation of the listening end in the actual communication system, and can effectively improve the communication concealment of the sending end and the receiving end; secondly, an information symbol is mapped into multiple time chips, and information is sent only during the time when the chip sequence is 1. Since the information symbol transmission rate is generally in the microsecond level, and the energy detection algorithm used by the listening end can only achieve millisecond-level detection, the present invention still maintains concealment under the efficient energy detection algorithm. Finally, since the detection result of the detector is independent of the form of the input signal, the time-hopping transmission sequence is arranged in the order of 1 in front and 0 in the back, such as 111000, which reduces the complexity of the receiving end in performing time-hopping synchronization. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The embodiments of the present invention are further described below with reference to the accompanying drawings, in which:

[0032] Figure 1A schematic diagram of a scenario simulation of a sending end, a receiving end, and a listening end according to an embodiment of the present invention;

[0033] Figure 2 A flow chart of a method for sending a wireless signal according to an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of the relationship between the frequency hopping period and the frequency synthesis time according to an embodiment of the present invention;

[0035] Figure 4 is a waveform diagram of an original transmitted wireless signal according to an embodiment of the present invention;

[0036] Figure 5 A schematic diagram of a time hopping transmission sequence generated according to a time hopping duty cycle and a waveform diagram of a time hopping signal for performing passband signal transmission according to the time hopping transmission sequence according to an embodiment of the present invention;

[0037] Figure 6 A schematic diagram of an occupied time slot for sending a passband signal and an occupied frequency band for sending a passband signal according to an embodiment of the present invention;

[0038] Figure 7 A flow chart of a method for acquiring a wireless signal according to an embodiment of the present invention;

[0039] Figure 8 A schematic diagram of the structure of a transmitting end for sending a wireless signal according to an embodiment of the present invention;

[0040] Fig. 9 A schematic diagram of the structure of a receiving end for acquiring a wireless signal according to an embodiment of the present invention;

[0041] Fig.10 The figure is a comparison chart of simulation practice results according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] As mentioned in the background technology section, in the existing covert communication technology, first of all, the traditional information security scheme based on encryption can only protect the transmitted signal from the perspective of calculation. With the enhancement of hardware processing power, the traditional encryption scheme based on calculation may fail and cannot effectively protect the transmitted information. Secondly, the application scenarios of the existing concealment evaluation and the actual communication system are different, resulting in the fact that the covert communication design scheme based on the existing concealment evaluation index cannot provide the best theoretical guidance for the actual covert communication system. In addition, in the actual communication system, the energy detection algorithm adopted by the monitoring end in the way of realizing covert communication through time hopping technology is efficient, and the transmitted signal can be detected in the form of multiple detections. At this time, the time hopping technology cannot improve the concealment of the system. Therefore, in order to further achieve the expected covert transmission requirements, the time hopping technology needs to make the transmission time slot of the transmitted signal low enough, and this scheme will significantly reduce the throughput of the system and cannot meet the transmission rate requirements of the communication system. Therefore, the role of the time hopping technology alone in improving the concealment of the system is limited. Finally, frequency hopping technology can improve the system's ability to resist fixed-frequency interference to a certain extent. However, in actual communication systems, due to hardware limitations, the frequency hopping signal rate is limited. Therefore, the ability of frequency hopping technology alone to improve the system's concealment is also limited. Therefore, there is an urgent need for a method that combines time hopping and frequency hopping technology to specifically design time hopping and frequency hopping parameters, so that both parties can effectively improve the communication concealment capability while ensuring the data transmission rate.

[0044] In view of the above problems, the present invention provides a method for sending and receiving wireless signals. When sending wireless signals, the frequency hopping rate, expected detection probability and detection performance parameters of the listening end are obtained, and the time hopping duty cycle is determined according to the detection performance parameters, the detection threshold set based on the detection performance parameters and the expected detection probability; the frequency hopping key is obtained, and the frequency hopping spectrum information is generated according to the frequency hopping rate and the frequency hopping key, and the time hopping transmission sequence is generated according to the time hopping duty cycle; the baseband signal is up-converted according to the frequency hopping spectrum information to obtain a passband signal; and the passband signal is controlled to be sent through the antenna at a specified time according to the time hopping transmission sequence. When obtaining wireless signals, the frequency hopping rate, frequency hopping key and time hopping duty cycle used when sending wireless signals are obtained; the frequency hopping spectrum information is generated according to the frequency hopping rate and the frequency hopping key, and the time hopping receiving sequence is generated according to the time hopping duty cycle; the antenna is controlled to receive the wireless signal at a specified time based on the time hopping receiving sequence; finally, the obtained wireless signal is down-converted using the frequency hopping spectrum information to obtain a baseband signal. Before sending a wireless signal, the present invention considers the expected detection probability that can be achieved within a reasonable parameter range and the detection performance of the monitoring terminal, obtains a time-hopping duty ratio, and controls the bandpass signal to be sent through the antenna at a specified time through a time-hopping transmission sequence generated by the time-hopping duty ratio, thereby reducing the proportion of the sent wireless signal to improve concealment, and a suitable time-hopping duty ratio can meet the demand for data transmission rate to a certain extent. Therefore, the combination of time-hopping technology and frequency-hopping rate further improves the concealment during wireless communication.

[0045] Before specifically introducing the embodiments of the present invention, some of the terms used therein are explained as follows:

[0046] Time-hopping duty cycle: It is the ratio of the actual transmission time of the wireless signal sent within a symbol period to the symbol period. The symbol period is the time required for continuous transmission of an information symbol.

[0047] False alarm probability value: when the transmitter does not send a signal, the listener will mistakenly judge that the transmitter is sending a signal due to the noise signal received by the listener.

[0048] Detection probability: It is the probability that the listening end detects the presence of a signal when the sending end sends a signal.

[0049] First, a wireless communication scenario is simulated and set up to explain the transmitter that sends wireless signals, the receiver that receives wireless signals, and the listener that detects wireless signals in the wireless communication scenario. According to one embodiment of the present invention, the arrangement of the transmitter A, the receiver B, and the listener W is as follows: Figure 1As shown, the transmitting end A sends a signal to the receiving end B through the transmitting channel, and the listening end W detects whether the transmitting end sends information by analyzing the signal received on the listening channel. At the same time, the transmitting channel and the listening channel can be set as AWGN channels. The transmitting end and the receiving end share an infinite length key to ensure the successful establishment of the communication link. The key information is not known by the listening end. In the present invention, the key information includes the frequency hopping rate, the frequency hopping key and the time hopping duty cycle information.

[0050] In order to increase the concealment of wireless signals and reduce the probability of the transmitted wireless signals being detected by the monitoring end, a method for transmitting wireless signals is provided according to an embodiment of the present invention. Figure 2 , including steps S1, S2, S3, and S4. In order to better understand the present invention, each step is described in detail below in conjunction with specific embodiments.

[0051] Step S1: Obtain a frequency hopping rate, an expected detection probability, and a detection performance parameter of the monitoring end, and determine a time hopping duty cycle according to the detection performance parameter, a detection threshold set based on the detection performance parameter, and the expected detection probability.

[0052] According to an embodiment of the present invention, the higher the frequency hopping rate, the lower the probability of the signal being detected. However, due to the limitation of the hardware level, there is a frequency switching time, during which information cannot be transmitted, resulting in a loss of frequency hopping performance. Figure 3 For example, in general engineering, the frequency synthesis time is required to be no more than 20% of the frequency hopping period. Therefore, after the hardware frequency synthesis time is determined, the maximum frequency hopping rate is limited. In the present invention, the frequency hopping rate can be set to 2000 hop / s. It should be understood that this is only for illustration, and the implementer can set it according to the specific scenario and needs. The present invention does not impose any restrictions on this. The expected detection probability is the optimal detection probability that the listening end can achieve when the transmitting end and the receiving end communicate, which fully considers the actual working mode of the listening end. The actual working mode of the listening end can be: by adopting a channelized receiver, a plurality of filters with a bandwidth of M are used to divide the listening channel into a plurality of sub-channels, so that the listening end can simultaneously detect the wireless signals received by the plurality of sub-channels. The channelized receiver can intercept and receive wireless signals of different frequency bands at the same time. After intercepting and receiving the wireless signal, the monitoring end first calculates the energy of the wireless signal received by each sub-channel, and compares the maximum received wireless signal energy and the corresponding frequency point with the preset threshold. When the wireless signal energy is greater than the preset threshold, it is confirmed that there is a sending signal on the frequency band, and further understands the received wireless signal or generates interference at the frequency point.

[0053] According to an embodiment of the present invention, the detection performance parameter includes a signal-to-noise ratio of a received signal at the monitoring end, and a method for obtaining the signal-to-noise ratio of a received signal at the monitoring end includes steps a1 and a2; wherein,

[0054] Step a1: Obtain the monitoring parameters of the monitoring end and the communication parameters of the transmitting end and the receiving end. The monitoring parameters include: the minimum monitoring distance between the monitoring end and the transmitting end, the channel fading factor, the channel noise power, the carrier wavelength, and the receiving antenna gain of the monitoring end and the transmitting antenna gain of the transmitting end. The communication parameters include: the target data transmission rate of the transmitting end and the transmitting antenna gain of the transmitting end; the minimum receiving signal-to-noise ratio of the receiving end and the receiving antenna gain of the receiving end; the distance between the transmitting end and the receiving end, the channel fading factor and the carrier wavelength.

[0055] Step a2: Calculate the minimum transmission signal power of the transmitting end based on the communication parameters between the transmitting end and the receiving end, and calculate the received signal signal-to-noise ratio of the monitoring end according to the monitoring parameters and the minimum transmission signal power.

[0056] According to one embodiment of the present invention, step a2 further includes the following steps:

[0057] Step a21: Calculate the minimum transmission signal power of the transmitter based on the communication parameters. The preferred calculation method includes: calculating the minimum reception signal power of the receiver based on the target data transmission rate and the minimum reception signal-to-noise ratio; calculating the minimum transmission signal power based on the minimum reception signal power, the distance between the transmitter and the receiver, the channel fading factor, the carrier wavelength, the transmission antenna gain and the reception antenna gain of the receiver. The communication parameters are the communication performance parameters of the legal communication parties (transmitter and receiver).

[0058] According to one embodiment of the present invention, after a target data transmission rate R is given, the minimum receiving signal-to-noise ratio of the receiving end is determined according to the Shannon channel capacity formula: R=log(1+snr), and the determination formula is as follows:

[0059]

[0060] Among them, snr is the minimum receiving signal-to-noise ratio at the receiving end, P r_receiver is the minimum received signal power at the receiving end, is the channel noise power received by the receiving end.

[0061] The minimum received signal power of the receiving end is determined according to the minimum received signal-to-noise ratio of the receiving end. The determination formula is as follows:

[0062]

[0063] Finally, the minimum signal power at the transmitter is calculated by combining the free space loss model. The calculation formula is as follows:

[0064]

[0065] Among them, P t_min is the minimum signal power sent by the transmitter, P r_receiver is the minimum received signal power at the receiving end, d tr is the distance between the transmitter and the receiver, l is the channel fading factor, G t is the transmitting antenna gain, G r is the receiving antenna gain at the receiving end, λ is the carrier wavelength, c = 3 × 10 8 m / s is the speed of light in a vacuum, and f is the carrier frequency.

[0066] Step a22: Calculate the received signal signal-to-noise ratio of the monitoring end according to the monitoring parameters and the minimum transmitted signal power. The specific calculation method includes: calculating the received signal power of the monitoring end according to the minimum transmitted signal power of the transmitting end, the transmitting antenna gain of the transmitting end, the receiving antenna gain of the monitoring end, the minimum monitorable distance between the monitoring end and the transmitting end, the channel fading factor and the carrier wavelength between the monitoring end and the transmitting end; calculating the received signal signal-to-noise ratio based on the received signal power and the channel noise power of the monitoring end.

[0067] After the minimum transmitted signal power is calculated according to step a21, the received signal power of the monitoring end can be calculated by the free space loss model. The calculation formula is as follows:

[0068]

[0069] Among them, P r_warden is the received signal power at the monitoring end, G r ′ is the receiving antenna gain of the monitoring end, d min It is the minimum monitoring distance between the monitoring end and the sending end.

[0070] The signal-to-noise ratio γ of the received signal at the monitoring end is further calculated according to the received signal power at the monitoring end. The calculation formula is as follows:

[0071]

[0072] Among them, γ is the signal-to-noise ratio of the received signal at the monitoring end, The noise power of the channel monitored by the monitoring end.

[0073] Since the higher the frequency hopping rate, the lower the probability of the signal being detected, the performance of the detector is limited by the frequency hopping rate set as above in a manner that limits the optimal detection time of the detector at the listening end on a single frequency band to a certain extent. According to one embodiment of the present invention, the detection performance parameter also includes a preset false alarm probability value and a detection time window length, wherein the detection time window length is determined in a manner that: a signal sampling frequency at the listening end is set, an optimal detection time is obtained based on the frequency hopping rate, and the detection time window length is determined according to the optimal detection time and the signal sampling frequency.

[0074] According to an embodiment of the present invention, a method for obtaining an optimal detection time based on a frequency hopping rate includes:

[0075] τ=1 / v hop ,

[0076] Among them, τ is the optimal detection time, v hop is the frequency hopping rate.

[0077] Determine the detection time window length based on the optimal detection time and signal sampling frequency, including:

[0078] L = τf s ,

[0079] Where L is the length of the detection time window, f s is the signal sampling frequency.

[0080] For the listening terminal, in order to reduce the invalid working influence of the false alarm probability value on it, the false alarm probability value can be made as low as possible by adjusting the detection threshold. The detection threshold at this time is not the optimal detection threshold that makes the sum of the false alarm probability and the missed detection probability reach the minimum. For the transmitting terminal, it is more concerned about whether the transmitted signal can be detected, and it is more hoped that the missed detection probability of the listening terminal is large. Therefore, the sum of the false alarm probability and the missed detection probability under the optimal detection threshold cannot well obtain the detection situation of the listening terminal in the actual communication system. Therefore, according to one embodiment of the present invention, the detection threshold is set according to the detection performance parameter of the listening terminal, including the following setting mode:

[0081]

[0082] Among them, ε is the detection threshold, Q is the complementary cumulative distribution function, P f is the preset false alarm probability value, L is the detection time window length, The detection threshold is set in combination with various detection performance parameters of the monitoring end to improve the accuracy of the detection situation of the monitoring end in the actual communication system, which can effectively improve the communication concealment of the sending end and the receiving end.

[0083] At present, in order to achieve the expected covert transmission requirements, it is necessary to make the signal transmission time slot low enough, resulting in a very small time hopping duty cycle, which significantly reduces the system throughput and cannot meet the data transmission rate requirements during communication. In order to set a suitable time hopping duty cycle, according to an embodiment of the present invention, the time hopping duty cycle is determined in the following manner:

[0084]

[0085] Where ρ is the time-hopping duty cycle, Q is the complementary cumulative distribution function, and P d is the expected detection probability, γ is the signal-to-noise ratio of the received signal at the listening end, L is the length of the detection time window, ε is the detection threshold, The present invention can set a suitable time-hopping duty cycle by using the time-hopping technology after the optimal detection time of the detector of the given listening end and the detection threshold in the actual communication system, and appropriately reduce the proportion of the transmitted signal input to the detector, thereby meeting the demand for data transmission rate during communication and further reducing the detection probability of the transmitted signal by the listening end.

[0086] Step S2: Acquire a frequency hopping key, generate frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generate a time hopping transmission sequence according to the time hopping duty cycle.

[0087] According to one embodiment of the present invention, before generating the frequency hopping spectrum information, multiple groups of frequency hopping keys are generally set in practice, and different frequency hopping keys correspond to different frequency hopping patterns for selection when used. Therefore, it is necessary to obtain one of the frequency hopping keys and control the generation of the frequency hopping spectrum information according to the frequency hopping key and the frequency hopping rate.

[0088] According to one embodiment of the present invention, the time-hopping transmission sequence includes a number of time chips indicating whether to send a passband signal; wherein the time chip indicating the sending of the passband signal and the number of all time chips in the time-hopping transmission sequence conform to the time-hopping duty cycle, and the time chip indicating the sending of the passband signal is arranged before the time chip indicating that the passband signal is not sent. In addition, the time chip is also generally called a chip. In the field of wireless communication, the time for transmitting an information symbol in a passband signal is divided into m (m is an integer greater than 1) short intervals, called chips. For example, assuming that m is 10, the time for transmitting one information symbol is divided into 10 time chips. The time-hopping transmission sequence can indicate that the information symbol is sent in some of the time chips, thereby achieving control of the passband signal to be sent through the antenna at a specified time according to the time-hopping transmission sequence.

[0089] According to one embodiment of the present invention, each information symbol in the passband signal is mapped into a time-hopping transmission sequence according to the time-hopping duty cycle. It is necessary to clarify that the symbol period is greater than the period of the time code chip. For example, the symbol period of an information symbol in the passband signal is 1ms, the time-hopping duty cycle is 0.5, and the period of the time code chip can be specified as 0.1ms. The information symbol is mapped into a time-hopping transmission sequence of the form 1111100000 according to the time-hopping duty cycle, wherein the first 5 time code chips of the time-hopping transmission sequence are time code chips indicating the transmission of the passband signal, and the last 5 time code chips are time code chips indicating that the passband signal is not transmitted. Since the information symbol transmission rate is generally in the microsecond level, and in the actual communication system, the energy detection algorithm used by the listening end can only achieve millisecond level detection. Therefore, multiple information symbols will be included in the detection time range of the detector of a listening end, so that the concealment is still maintained under the efficient energy detection algorithm.

[0090] According to an embodiment of the present invention, the time code chip indicating the sending of the passband signal is arranged before the time code chip indicating the non-sending of the passband signal, thereby reducing the complexity of time hopping synchronization at the receiving end.

[0091] Before setting the time-hopping duty cycle, refer to Figure 4 , the horizontal axis of the coordinate system represents time, the vertical axis represents amplitude, and the coordinate system is the waveform of the original transmitted wireless signal, indicating that the wireless signal is continuously transmitted within a symbol period. After setting the time hopping duty cycle, see Figure 5 , including two coordinate systems, and the horizontal axis of each coordinate system represents time, and the vertical axis represents amplitude. The upper coordinate system is the time-hopping transmission sequence when the time-hopping duty cycle is 0.5, and the time-hopping signal waveform of the coordinate system corresponding to the time-hopping transmission sequence below the time-hopping transmission sequence. The time-hopping signal waveform indicates that the first half of the symbol period in a symbol period is transmitting wireless signals, and the second half of the symbol period is in an idle state. In a section where the time-hopping signal waveform is 0, the detector at the listening end detects only noise signals, which reduces the detection probability of the listening end to a certain extent and improves the concealment of the communication signal.

[0092] Step S3: up-convert the baseband signal according to the frequency hopping spectrum information to obtain a passband signal to be transmitted.

[0093] According to an embodiment of the present invention, the baseband signal is obtained by encoding and modulating the received information bits in sequence at the transmitting end.

[0094] Step S4: Control the passband signal to be sent through the antenna at a specified time according to the time hopping transmission sequence to obtain a wireless signal.

[0095] According to one embodiment of the present invention, see Figure 6, including the passband signal obtained according to the frequency hopping spectrum information and the time hopping transmission sequence obtained according to the time hopping duty cycle, and the distribution diagram of occupied time slots and occupied frequency bands when the passband signal is sent. The horizontal axis is time, represented by T, and the vertical axis is the frequency hopping frequency at the corresponding time, represented by F.

[0096] According to an embodiment of the present invention, a method for acquiring a wireless signal is provided. Figure 7 , including steps A1, A2, A3, and A4.

[0097] Step A1: Acquire the frequency hopping rate, frequency hopping key and time hopping duty cycle used when sending wireless signals according to the above embodiment of the present invention.

[0098] Step A2: Generate frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generate a time hopping receiving sequence according to the time hopping duty cycle.

[0099] Step A3: Control the antenna to receive the wireless signal at a specified time based on the time hopping reception sequence.

[0100] According to one embodiment of the present invention, the frequency hopping spectrum information and the time hopping receiving sequence are generated in the same manner as the transmitting end, and the time hopping receiving sequence includes a number of time code chips indicating whether to receive wireless signals, wherein the number ratio of the time code chips indicating the reception of wireless signals to the total number of time code chips conforms to the time hopping duty cycle, and the time code chips indicating the reception of wireless signals are arranged before the time code chips indicating the non-reception of wireless signals. The time hopping receiving sequence is in the form of 1111100000, wherein the first 5 time code chips of the time hopping receiving sequence are time code chips indicating the reception of wireless signals, and the last 5 time code chips are time code chips indicating the non-reception of wireless signals.

[0101] Step A4: Obtain the received wireless signal, and down-convert the wireless signal using the frequency hopping spectrum information to obtain a baseband signal.

[0102] According to one embodiment of the present invention, a wireless transmitting end (corresponding to the transmitting end) for use in the above-mentioned method for transmitting a wireless signal of the present invention is provided, see Figure 8, including an encoder and a modulator, encoding the encoder information bits, and the modulator modulating the encoded information bits to obtain a baseband signal. In addition, it also includes: a frequency hopping and time hopping parameter configuration module, which is used to obtain the frequency hopping rate, the expected detection probability and the detection performance parameters of the monitoring end, and determine the time hopping duty cycle according to the detection performance parameters, the detection threshold set based on the detection performance parameters and the expected detection probability. The frequency hopping and time hopping module is used to obtain the frequency hopping key, generate the frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generate the time hopping transmission sequence according to the time hopping duty cycle. The first mixer is used to up-convert the baseband signal according to the frequency hopping spectrum information to obtain the bandpass signal to be transmitted. The first high-frequency switch is used to control the bandpass signal to be sent through the transmitting antenna at a specified time according to the time hopping transmission sequence to obtain a wireless signal. The transmitting antenna is used to send the bandpass signal, the frequency hopping rate, the frequency hopping key and the time hopping duty cycle at a specified time.

[0103] According to one embodiment of the present invention, a passband signal is transmitted through an antenna at a specified time according to a time-hopping transmission sequence control, including using the time-hopping transmission sequence to control the on and off of a first high-frequency switch, turning on the first high-frequency switch to transmit the passband signal when the time-hopping transmission sequence is 1, and turning off the first high-frequency switch to not transmit the passband signal when the time-hopping transmission sequence is 0.

[0104] According to one embodiment of the present invention, a wireless receiving end (corresponding to a receiving end) for the above-mentioned method for acquiring a wireless signal of the present invention is provided, see Fig. 9 , including: a receiving antenna, used to receive wireless signals, frequency hopping rate, frequency hopping key and time hopping duty cycle at a specified time. A time hopping and frequency hopping parameter synchronization module, used to obtain the frequency hopping rate, frequency hopping key and time hopping duty cycle used when sending wireless signals according to the above-mentioned method of the present invention, and at the same time, synchronize the frequency of the receiving end with that of the transmitting end, and synchronize the time of the receiving end with that of the transmitting end. A frequency hopping and time hopping receiving module, used to generate frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and to generate a time hopping receiving sequence according to the time hopping duty cycle. A second high-frequency switch, used to control the receiving antenna to receive wireless signals at a specified time based on the time hopping receiving sequence. A second mixer, used to obtain the received wireless signal, and down-convert the wireless signal using the frequency hopping spectrum information to obtain a baseband signal. In addition, it also includes a demodulator, used to demodulate the baseband signal. A decoder, used to decode the demodulated baseband signal to obtain information bits.

[0105] According to one embodiment of the present invention, the antenna is controlled to receive wireless signals at a specified time according to a time-hopping receiving sequence, including using the time-hopping receiving sequence to control the on and off of a second high-frequency switch, turning on the second high-frequency switch to receive wireless signals when the time-hopping receiving sequence is 1, and turning off the second high-frequency switch to not receive wireless signals when the time-hopping receiving sequence is 0.

[0106] According to one embodiment of the present invention, a wireless communication system is provided, comprising: a transmitting end based on the method for sending a wireless signal described in the above embodiment of the present invention and a receiving end based on the method for acquiring a wireless signal described in the above embodiment of the present invention.

[0107] In order to illustrate the effect of the present invention, the inventors conducted simulation verification on the method of the present invention, and the simulation parameters are shown in Table 1.

[0108] Table 1: Simulation parameter settings

[0109]

[0110] Parameter Description:

[0111] False alarm probability value: According to the Nyquist theorem, the monitoring end uses a sampling rate that is twice the bandwidth of the transmitted wireless signal to obtain all the information of the transmitted wireless signal. Therefore, in the simulation practice, the false alarm probability value is generally set to 0.05.

[0112] The minimum listening distance between the transmitter and the listener: It is generally believed that when the distance between the listener and the transmitter is less than d min The listener will be discovered by the sender, so the sender can take measures to attack or evade the listener. min Set to 6km.

[0113] According to the above simulation parameters, the method of sending wireless signals at the transmitter is simulated and practiced:

[0114] After the target data transmission rate R is given, the minimum receiving signal-to-noise ratio at the receiving end is determined according to the Shannon channel capacity formula: R = log(1 + snr). The determination formula is as follows:

[0115]

[0116] Among them, snr is the minimum receiving signal-to-noise ratio at the receiving end, P r_receiver is the minimum received signal power at the receiving end, is the channel noise power received by the receiving end.

[0117] The minimum received signal power of the receiving end is determined according to the minimum received signal-to-noise ratio of the receiving end. The determination formula is as follows:

[0118]

[0119] Finally, combined with the free space loss model, the minimum transmitted signal power P at the transmitter is calculated. t_min =1.09w.

[0120] Combined with the minimum signal power of the transmitter, the minimum listening distance d between the transmitter and the listening end is min According to the free space loss model, the received signal power at the listening end can be calculated

[0121] Further, the signal-to-noise ratio of the received signal at the listening end is calculated according to the received signal power at the listening end.

[0122] According to L = τf s , τ=1 / v hop , it can be determined that the monitoring end detection time window length (ie, the number of sampling points) L = 3000.

[0123] Given a false alarm probability value P f = 0.05, we can know the detection threshold

[0124] To further make the expected detection probability of the monitoring end lower than 0.5, according to the formula

[0125] It can be obtained that in this simulation practice, considering the expected detection probability P d =0.5, Q -1 (P d )=0, The calculated duty cycle ρ that meets the requirement is 0.673103156641033.

[0126] The simulation results are as follows Fig.10 As shown, the horizontal axis is the detection time of the listening end detecting the communication signal, and the vertical axis is the detection probability of the listening end at the corresponding detection time. Fig.10 The detection probabilities corresponding to three methods of sending wireless signals are: a frequency hopping communication system with only a frequency hopping signal (hopping rate of 2000 hop / s), a time hopping communication system with only a time hopping signal (time hopping duty cycle of 0.67), and a time hopping frequency hopping communication system with a time hopping frequency hopping signal (both the frequency hopping rate of 2000 hop / s and the time hopping duty cycle of 0.67 are set). The detection probabilities of the communication signals of each communication system are compared by the monitoring end. According to the results in the figure, compared with the separate time hopping communication system and frequency hopping communication system, the time hopping frequency hopping communication system combines the advantages of time hopping technology and frequency hopping technology, and can effectively improve the concealment of the communication signal.

[0127] It should be noted that although the above describes the various steps in a specific order, it does not mean that the various steps must be executed in the above specific order. In fact, some of these steps can be executed concurrently or even in a different order as long as the required functions can be achieved.

[0128] The present invention may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present invention.

[0129] Computer readable storage medium can be a tangible device that holds and stores instructions used by an instruction execution device. Computer readable storage medium can include, for example, but is not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (non-exhaustive list) of computer readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, for example, a punch card or a protruding structure in a groove on which instructions are stored, and any suitable combination thereof.

[0130] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for sending a wireless signal, characterized in that: include: Obtaining a frequency hopping rate, an expected detection probability, and a detection performance parameter of the listening end, and determining a time hopping duty cycle according to the detection performance parameter, a detection threshold set based on the detection performance parameter, and the expected detection probability; Obtain a frequency hopping key, generate frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generate a time hopping transmission sequence according to the time hopping duty cycle; Up-converting the baseband signal according to the frequency hopping spectrum information to obtain a bandpass signal to be transmitted; Control the passband signal to be sent through the antenna at a specified time according to the time hopping transmission sequence; The detection threshold value set based on the detection performance parameter may be set in the following manner: Among them, ε is the detection threshold, Q is the complementary cumulative distribution function, P f is the preset false alarm probability value, L = τf s , L is the detection time window length, the optimal detection time τ=1 / v hop , v hop is the frequency hopping rate, f s is the signal sampling frequency, σ u 2 is the channel noise power at the listening end; The time hopping duty cycle is determined in the following manner: Where ρ is the time-hopping duty cycle, Q is the complementary cumulative distribution function, and P d is the expected detection probability, γ is the signal-to-noise ratio of the received signal at the listening end, L = τf s , L is the detection time window length, the optimal detection time τ=1 / v hop , v hop is the frequency hopping rate, f s is the signal sampling frequency, is the channel noise power at the listening end.

2. The method according to claim 1, characterized in that The detection performance parameter includes a received signal signal-to-noise ratio, and the received signal signal-to-noise ratio is obtained by: Obtain the monitoring parameters of the monitoring end and the communication parameters between the sending end and the receiving end; The minimum transmission signal power of the transmitting end is calculated based on the communication parameters between the transmitting end and the receiving end, and the signal-to-noise ratio of the receiving signal is calculated according to the monitoring parameters and the minimum transmission signal power.

3. The method according to claim 2, characterized in that The monitoring parameters include: the minimum monitoring distance between the monitoring end and the transmitting end, the channel fading factor, the channel noise power, the carrier wavelength, and the receiving antenna gain of the monitoring end and the transmitting antenna gain of the transmitting end; Calculating the received signal-to-noise ratio includes: Calculate the received signal power of the monitoring end according to the minimum transmitted signal power, the minimum monitorable distance, the channel fading factor, the transmitting antenna gain of the transmitting end, the receiving antenna gain of the monitoring end and the carrier wavelength; The received signal-to-noise ratio is calculated based on the received signal power and channel noise power at the monitoring end.

4. The method according to claim 2, characterized in that: The detection performance parameters also include a preset false alarm probability value and a detection time window length, wherein the detection time window length is determined in the following manner: The signal sampling frequency of the monitoring end is set, the optimal detection time is obtained based on the frequency hopping rate, and the detection time window length is determined according to the optimal detection time and the signal sampling frequency.

5. The method according to claim 2, characterized in that: The communication parameters include: The target data transmission rate of the transmitter and the transmit antenna gain of the transmitter; The minimum receiving signal-to-noise ratio and receiving antenna gain of the receiving end; The distance between the transmitter and receiver, the channel fading factor and the carrier wavelength.

6. The method according to claim 5, characterized in that The minimum transmission signal power calculation method includes: Based on the target data transmission rate and the minimum receiving signal-to-noise ratio, the minimum receiving signal power at the receiving end is calculated; The minimum transmit signal power is calculated based on the minimum receive signal power, the distance between the transmit end and the receive end, the channel fading factor, the carrier wavelength, the transmit antenna gain, and the receive antenna gain of the receive end.

7. The method according to claim 1, characterized in that The time-hopping transmission sequence includes a number of time code chips indicating whether to transmit a passband signal; The time-hopping transmission sequence indicates that the number of time code chips for sending the passband signal and the total number of time code chips conforms to the time-hopping duty cycle, and the time code chips indicating the sending of the passband signal are arranged before the time code chips indicating that the passband signal is not sent.

8. A method for acquiring a wireless signal, characterized in that: include: Obtaining a frequency hopping rate, a frequency hopping key, and a time hopping duty cycle used when sending a wireless signal according to the method of any one of claims 1 to 7; Generate frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generate a time hopping receiving sequence according to the time hopping duty cycle; Controlling the antenna to receive wireless signals at a specified time based on a time hopping reception sequence; The received wireless signal is acquired, and the frequency hopping spectrum information is used to down-convert the wireless signal to obtain a baseband signal.

9. The method according to claim 8, characterized in that The time-hopping reception sequence includes several time code chips indicating whether to receive wireless signals, wherein the ratio of the time code chips indicating the reception of wireless signals to the total number of time code chips conforms to the time-hopping duty cycle, and the time code chips indicating the reception of wireless signals are arranged before the time code chips indicating the non-reception of wireless signals.

10. A wireless transmitting end used in the method according to any one of claims 1 to 7, characterized in that: include: A frequency hopping and time hopping parameter configuration module, used to obtain a frequency hopping rate, an expected detection probability and a detection performance parameter of a listening end, and determine a time hopping duty cycle according to the detection performance parameter, a detection threshold set based on the detection performance parameter and the expected detection probability; The frequency hopping time hopping module is used to obtain the frequency hopping key, generate the frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and generate the time hopping transmission sequence according to the time hopping duty cycle; A first mixer, used for up-converting the baseband signal according to the frequency hopping spectrum information to obtain a bandpass signal to be transmitted; The first high-frequency switch is used to control the bandpass signal to be sent through the antenna at a specified time according to the time-hopping transmission sequence to obtain a wireless signal.

11. A wireless receiving end used in the method according to any one of claims 8 or 9, characterized in that: include: A time-hopping and frequency-hopping parameter synchronization module, used to obtain the frequency hopping rate, frequency hopping key and time-hopping duty cycle used when sending a wireless signal by the method described in any one of claims 1 to 7; A frequency hopping time hopping receiving module, used to generate frequency hopping spectrum information according to the frequency hopping rate and the frequency hopping key, and to generate a time hopping receiving sequence according to the time hopping duty cycle; A second high frequency switch, used to control the antenna to receive the wireless signal at a specified time based on the time hopping reception sequence; The second mixer is used to obtain the received wireless signal and down-convert the wireless signal using the frequency hopping spectrum information to obtain a baseband signal.

12. A wireless communication system, characterized in that: include: The wireless transmitter according to claim 10; and The wireless receiving terminal as claimed in claim 11.

13. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and the computer program can be executed by a processor to implement the steps of the method according to any one of claims 1 to 9.

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