A communication anti-interference method based on interference amplification cancellation mode

Abstract

A communication anti-interference method based on interference amplification cancellation mode, comprising a transmitter, an interference machine and a receiver, the interference machine transmits interference signals to the transmitter and the receiver, the transmitter re-modulates the received interference signals according to the amplification factor by using a programmable gain amplifier according to the transmitted information bits, generates a transmission signal and transmits it to the receiver, and the receiver performs energy detection based on the received interference signals from the interference machine and the transmission signals from the transmitter to eliminate interference.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication anti-interference technology, and in particular to a communication anti-interference method based on interference amplification and cancellation mode. Background Technology

[0002] Defending against strong suppression interference in complex electromagnetic environments has always been a challenge in the field of anti-jamming communications. Traditional anti-jamming techniques, such as direct sequence spread spectrum and frequency hopping spread spectrum, are mainly designed for narrowband interference attacks, ensuring communication reliability through interference avoidance, but they require more additional time / frequency resources. Interference cancellation methods mostly suppress unwanted signals within the operating frequency band using filters, but their defense against strong suppression interference is relatively weak.

[0003] In recent years, jamming modulation based active anti-jamming (JM-AAJ) communication systems have used jamming signals as carrier modulation information to improve communication reliability under strong jamming suppression. The signal transmission and reception process of traditional active anti-jamming communication systems is as follows: Figure 1 As shown, the system model in this scheme consists of a transmitter, a receiver, and a jammer. The channel coefficients for the jammer-to-transmitter (JT), transmitter-to-receiver (TR), and jammer-to-receiver (JR) links are respectively... This means that the jammer transmits jamming signals to the transmitter and receiver to suppress legitimate communication. The transmitter amplifies the received jamming signal using a programmable gain amplifier (PGA) based on the transmitted information bits (achieving jamming modulation) and immediately sends it to the receiver.

[0004] Traditional active anti-jamming communication systems utilize the on / off state of a programmable gain amplifier (PGA) to remodulate the received signal based on the transmitted information bits, without requiring prior knowledge of the channel state. The transmitted signal is represented as:

[0005]

[0006] In the formula This is an unknown interference signal. The amplification factor corresponding to each different information state is: .

[0007] For traditional binary information sources, i.e. Traditional active anti-jamming communication systems It can be rewritten as:

[0008]

[0009] The average transmit power of the PGA introduced by the amplification factor can be expressed as:

[0010]

[0011] in, and These represent the probabilities of emitting "0" or "1", respectively. Typically, let... .

[0012] At the receiver, the omnidirectional receiving antenna receives the superposition of the interference signal from the jammer-to-receiver link (JR link) and the readjustment signal from the transmitter-to-receiver link (TR link). Then, the received signal... It can be represented as:

[0013]

[0014] in, This represents the delay between the JR and JT-TR links. For ease of calculation, both PGA noise and the additional white Gaussian noise (AWGN) are combined into a single noise term. The noise term is an independent, uniformly distributed, circularly symmetric complex Gaussian noise with zero mean and variance. For traditional active anti-jamming communication systems, the higher the interference power, the stronger the transmitted signal, and it will not cause a disconnection. Furthermore, signal modulation and demodulation are performed in the energy domain, making them insensitive to the bandwidth of the interference signal. However, in scenarios with a high interference-to-noise ratio (SINR), the bit error rate (BER) performance exhibits a plateau, meaning its resistance to strong suppression interference is limited. This is because the BER is related to the system's SINR (signal power / (interference power + noise power)). In traditional active anti-jamming communication methods, the PGA only has two states (on / off), which cannot fully utilize the advantages of interference modulation. Therefore, when the interference-to-noise ratio is high, the SINR approaches a constant value, which is expressed as:

[0015] . Summary of the Invention

[0016] To address the problem that traditional active anti-interference communication systems suffer from a flat bit error rate when the interference-to-noise ratio (the ratio of interference to noise energy) is high, i.e., limited ability to resist strong suppression interference, this invention provides a communication anti-interference method based on interference amplification and cancellation mode.

[0017] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0018] On the one hand, the present invention provides a communication anti-interference method based on interference amplification cancellation mode, including a transmitter, a jammer, and a receiver. The jammer transmits an interference signal to the transmitter and the receiver. The transmitter, based on the information bits to be transmitted, uses a programmable gain amplifier (PGA) to remodulate the received interference signal according to the amplification factor, generates a transmission signal, and forwards it to the receiver. The receiver distinguishes the transmitted information bits by energy detection (comparing the value with a set energy judgment threshold) to reduce the impact of strong interference on communication reliability.

[0019] Both the transmitter and receiver operate in full-duplex mode, allowing simultaneous signal reception and transmission within the same time slot. The transmitter's transmitted signal... Represented as:

[0020]

[0021] In the formula, For the received unknown interference signal, The amplification factor corresponding to each different information state is: ;

[0022] When, for the amplification factor for:

[0023]

[0024] in , These are the channel coefficients for the jammer-to-transmitter link, the transmitter-to-receiver link, and the jammer-to-receiver link, respectively. This represents the average transmit power of the programmable gain amplifier.

[0025] Amplification factor introduces the average transmit power of the programmable gain amplifier Represented as:

[0026]

[0027] in, and These represent the probability of firing "0" or "1", respectively.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] This invention provides a communication anti-interference method based on interference amplification cancellation mode. Amplification cancellation refers to adjusting the amplification factor of the programmable gain amplifier (PGA) in the transmitter to achieve more significant energy differentiation at the receiver end. Specifically, the first-state signal can cancel the energy of the received signal, and the second-state signal can be amplified by accumulating the energy of the received signal, thus solving the BER flattening problem of the traditional JM-AAJ method under high interference-to-noise ratio. Specifically, it is manifested in:

[0030] By designing the amplification factor of the programmable gain amplifier (PGA) in the transmitter, it is possible to achieve the cancellation of the first-state signal energy with the received signal energy and the accumulation and amplification of the second-state signal energy with the received signal energy at the receiver. Theoretically, this is reflected in eliminating the asymptotic value limitation caused by interference signals in the SINR denominator, thereby solving the BER leveling problem of the traditional JM-AAJ method at high interference-to-noise ratios.

[0031] The receiver decodes the interference-modulated signal through energy detection. Since traditional decoding methods based on inverse transformation or direct information bit decision fail, this invention achieves decoding by utilizing the signal energy differences of different transmitted information bits at the receiving end.

[0032] Furthermore, the theoretical optimal BER can be achieved through the design of the detection threshold. The essence of energy detection is the relationship between the received signal energy and the detection threshold, which has a theoretically closed-form expression and embodies the optimization concept.

[0033] In summary, this invention proposes a communication anti-interference method based on interference amplification cancellation mode. It utilizes the interference cancellation and amplification states of the PGA to transmit information bits, thereby achieving reliable communication under interference attacks. Since JM-JEA can more effectively distinguish the energy of the transmitter in two information states (transmitting 0 or 1), it significantly improves the BER (bit / effect) under high interference-to-noise ratio (INR) conditions. Furthermore, theoretical analysis verifies the BER performance of JM-JEA, yielding the optimal energy detection threshold. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the signal transmission and reception process of an active anti-interference communication system.

[0036] Figure 2 This is a schematic diagram of the signal transmission and reception process of the communication system of the present invention;

[0037] Figure 3 This is a comparison chart of the BER performance of the communication anti-interference method based on the traditional JM-AAJ and the interference amplification cancellation mode proposed in this invention in one embodiment. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] In one embodiment, a communication anti-interference method based on interference amplification cancellation mode is provided, including a transmitter, a jammer, and a receiver. The jammer transmits an interference signal to the transmitter and the receiver. The transmitter uses a programmable gain amplifier (PGA) to remodulate the received interference signal according to the amplification factor based on the transmitted information bits, and generates a transmission signal to forward to the receiver. The receiver distinguishes the transmitted information bits by energy detection (comparing the value with a set energy judgment threshold) to reduce the impact of strong interference on communication reliability.

[0040] Reference Figure 2 This is a schematic diagram of the signal transmission and reception process of a communication system in one embodiment. The system model consists of a transmitter, a receiver, and a jammer. Both the transmitter and receiver operate in full-duplex mode, allowing simultaneous signal reception and transmission within the same time slot. The channel coefficients of the jammer-to-transmitter (JT), transmitter-to-receiver (TR), and jammer-to-receiver (JR) links are respectively... This refers to the jamming mechanism that transmits interference signals to both the transmitter and receiver to suppress legitimate communication. The original digital information (0 / 1 sequence) to be transmitted enters the transmitter in the form of a "bit stream." It is first converted into symbols by baseband signal processing, and then remodulated by a programmable gain amplifier (PGA) according to the amplification factor before being sent to the receiver. The receiver uses an analog-to-digital converter (ADC), filtering, and sampling to process the data. Energy detection (comparing the data to a set energy threshold) is then used to distinguish the transmitted information bits in order to recover the original bit stream, thereby reducing the impact of strong interference on communication reliability.

[0041] The baseband signal generation module in the receiver is used to unify the radix and number of information states of the signal source. For example, in the communication anti-interference method based on interference amplification cancellation mode proposed in this invention, the number of information states... When, i.e., PGA amplification factor There are two possible values, corresponding to transmitting 0 or 1 respectively. If the bitstream (source) is binary, no conversion is needed. If the bitstream (source) is decimal, the decimal number needs to be converted to binary before proceeding. In subsequent explanations, the bitstream will be assumed to be binary and... .

[0042] Amplification factor controller in the receiver: realizes the PGA amplification factor The calculation, used as input to the PGA, transforms the 0 / 1 sequence into... , ,have:

[0043]

[0044] PGA: Based on the amplification factor given by the amplification factor controller, the baseband signal is modulated onto the received interference signal, i.e., according to the 0 and 1 corresponding to... , The interference signal is amplified to varying degrees and then forwarded to the receiver.

[0045] Specifically, the transmitter's transmitted signal for:

[0046]

[0047] In the formula, For the received unknown interference signal, The amplification factor corresponding to each different information state is: ;

[0048] For binary information sources, When sending "0" or "1", the amplification factor is... ;

[0049] The amplification factor for:

[0050]

[0051] in , These represent the channel coefficients for the jammer-to-transmitter link, transmitter-to-receiver link, and jammer-to-receiver link, respectively; the average transmit power of the programmable gain amplifier introduced by the amplification factor. Represented as:

[0052]

[0053] in, and Let represent the probability of emitting "0" or "1" respectively. Typically, let .

[0054] For slowly varying channels (which can be considered constant channels), the receiver uses pilot symbols for signal input. Channel estimation can be performed using existing pilot-based channel estimation methods. Both the transmitter and receiver know the pilot information; the receiver extracts the pilot signals at known locations, represented as:

[0055]

[0056] in, The channel matrix is ​​the location of the pilot signals. Given the pilot matrix, This is noise. For example, using the least squares channel estimation method, the channel estimate is... . It is estimated by the ratio of the interference power received by the receiver and transceiver.

[0057] The receiver at the set sampling interval The length of the interference signal received by sampling is The receiver will be set to collect data at the specified interval. The sequence of interference signals received by sampling is represented as follows: ,in, For the receiver to collect data at the set interval The first of the received interference signal sequence One point, ,have:

[0058]

[0059] In the formula For the receiver to collect data at the set interval The first of the received interference signal sequence Additive white Gaussian noise (AWGN) at each point. . It indicates that it follows a complex Gaussian distribution with a mean of 0 and a variance of . Specific values ​​are generally not set. For the interference signal One sampling point.

[0060] The transmitter at the set acquisition interval The length of the interference signal received by sampling is The transmitter will be set to collect data at the designated interval. The sequence of interference signals received by sampling is represented as follows: ,in, This indicates that the transmitter is at the set acquisition interval. The first of the received interference signal sequence Points ,have:

[0061]

[0062] In the formula For the transmitter to collect data at the set interval The first of the received interference signal sequence Additive white Gaussian noise (AWGN) at each point. Same as above. It indicates that it follows a complex Gaussian distribution with a mean of 0 and a variance of . Specific values ​​are generally not set.

[0063] Represented as:

[0064]

[0065] When the interference signal is transmitted at extremely high power, i.e., in the high JNR region ( The second term in the numerator and denominator can be ignored, and in this case, we have an approximation. That's reasonable.

[0066] It has The signal received by the receiver can be represented as:

[0067]

[0068] in and This indicates that the transmitted information is "0" and "1" respectively, and the receiver operates at the set acquisition interval. Sampled received signal sequence include , ,in , Representing signal sequences respectively The information sent is a sequence of information corresponding to "0" and "1". For the receiver to collect data at the set interval Sampled received signal sequence The Additive white Gaussian noise (AWGN) at each point.

[0069] To recover the information bits, an energy detector is used in the receiver. The receiver distinguishes the transmitted information bits by detecting the energy of the received signal. Represented as:

[0070]

[0071] The energy detection and decoding process of the energy detector is represented as follows:

[0072]

[0073] in, and These represent the transmitter sending "0" and "1" respectively. Indicates the detection threshold, when When, it indicates decoding. Set to 1, otherwise decode. It is 0.

[0074] Furthermore, the detection threshold The closed-form expression for the optimal value is:

[0075]

[0076] In the formula, This represents the variance of the signal received at the receiving end when the transmitted information is "1". , Indicates the variance of the interference signal. This represents the variance of the noise signal.

[0077] Reference Figure 3 The figure shows a comparison of the BER performance of the communication anti-interference method based on the traditional JM-AAJ and the interference amplification cancellation mode proposed in this invention in one embodiment. Figure 3 The BER performance of the traditional JM-AAJ and the communication anti-interference method based on interference amplification cancellation mode proposed in this invention was compared, where the channel response was set to 1, i.e. As can be seen, the communication anti-interference method based on interference amplification cancellation mode proposed in this invention overcomes the BER flattening problem of traditional methods and has better anti-interference capability in scenarios with high JNR.

[0078] Matters not covered in this invention are common knowledge.

[0079] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A communication anti-interference method based on interference amplification and cancellation mode, characterized in that, It includes a transmitter, a jammer, and a receiver. The jammer transmits jamming signals to the transmitter and receiver. The transmitter uses a programmable gain amplifier to remodulate the received jamming signal according to the amplification factor based on the information bits to be transmitted, and generates a transmission signal to be forwarded to the receiver. The receiver distinguishes the transmitted information bits through energy detection to reduce the impact of strong interference on communication reliability. Both the transmitter and the receiver operate in full-duplex mode, allowing signals to be received and transmitted simultaneously in the same time slot. Transmitter's transmission signal for: In the formula For the received unknown interference signal, The amplification factor corresponding to each different information state is: ; When, for the amplification factor for: in , These are the channel coefficients for the jammer-to-transmitter link, the transmitter-to-receiver link, and the jammer-to-receiver link, respectively. This represents the average transmit power of the programmable gain amplifier; The signal received by the receiver is represented as: in and This indicates that the transmitted information is "0" and "1" respectively, and the receiver operates at the set acquisition interval. Sampled received signal sequence include , ,in , Representing signal sequences respectively The information sent is a sequence of information corresponding to "0" and "1". For the receiver to collect data at the set interval Sampled received signal sequence The Additive white Gaussian noise at each point; The receiver distinguishes transmitted information bits through energy detection, and the received signal energy... Represented as: The energy detection and decoding process is represented as follows: in, and These represent the transmitter sending "0" and "1" respectively. Indicates the detection threshold, when At that time, it indicates decoding. Set to 1, otherwise decode. It is 0.

2. The communication anti-interference method based on interference amplification cancellation mode according to claim 1, characterized in that, The average transmit power of a programmable gain amplifier is expressed as: in, and These represent the probability of firing "0" or "1", respectively.

3. The communication anti-interference method based on interference amplification cancellation mode according to claim 2, characterized in that, 。 4. The communication anti-interference method based on interference amplification cancellation mode according to claim 1, 2, or 3, characterized in that, Detection threshold The closed-form expression for the optimal value is: In the formula, This represents the variance of the signal received at the receiving end when the transmitted information is "1". , Indicates the variance of the interference signal. This represents the variance of the noise signal.

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