A high-speed frequency hopping anti-interference method and system based on SIMO multi-channel

Abstract

The present invention discloses a high-speed frequency hopping anti-interference method and system based on SIMO multi-channel, including a transmitting end and a receiving end; the transmitting end includes a turbo encoding module, a first time slot control module, a framing module, a modulation module, a first digital filter and a first radio frequency control module; the receiving end includes a multi-channel receiving antenna, a second time slot control module, a second radio frequency control module, a receiving diversity processing module, a second digital filter, a synchronization module, a demodulation module and a turbo decoding module. The present invention ensures the stability and reliability of the wireless communication system without increasing the system transmission power consumption, and improves its anti-interference ability in complex environments.

Description

Technical Field

[0001] The present invention relates to the field of frequency hopping communication, and in particular to a high-speed frequency hopping anti-interference method and system based on SIMO (single-input multiple-output) multi-channel. Background Art

[0002] Electromagnetic interference is changeable, which has a serious impact on the stability and reliability of military wireless communications. Although traditional frequency hopping has good anti-interference capabilities and concealment means, with the widespread application of wireless communications and the continuous strengthening of military interference technology, traditional single-channel frequency hopping anti-interference means have certain limitations. When interference sources appear in the environment, certain frequency points in the frequency hopping signal will be affected, which will lead to an increase in the system's receiving bit error rate; when the environment and terrain are more complex, the wireless signal will produce multipath fading in the channel propagation, which will also affect the system's receiving bit error rate; in order to solve the above problems, most of the frequency hopping systems used in China are implemented by increasing the number of transmitting antennas, which undoubtedly increases the power consumption and cost of the system. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a high-speed frequency hopping anti-interference method and system based on SIMO multi-channel, which ensures the stability and reliability of the wireless communication system without increasing the system transmission power consumption and improves its anti-interference ability in complex environments.

[0004] The object of the present invention is achieved through the following technical scheme: a high-speed frequency hopping anti-interference method based on SIMO multi-channel, comprising the following steps:

[0005] S1. At the transmitting end of the signal, the data is turbo-encoded and sent to the framing module;

[0006] S2. The framing module divides the turbo-encoded data into several groups according to the information sent by the first time slot control module and adds the frequency number, and then adds the frequency hopping protection sequence and the pilot sequence to each group of data, and then sends it to the modulation module;

[0007] S3. The data group of the allocated frequency information is sent to the modulation module for modulation, and the modulated data is digitally filtered through the first digital filter;

[0008] S4. In the first RF control module, the digitally filtered signal is transmitted to the wireless channel through a single antenna after passing through a DAC, an up-conversion module and a power amplifier;

[0009] S5. At the receiving end, signals are received by multiple receiving antennas respectively, and the second RF control module processes the multiple signals received by the antennas respectively through a down-conversion module, a filter and an amplifier according to the information input by the second time slot control module, and then converts the signals into digital signals through the ADC and sends them to the receiving diversity processing module;

[0010] S6. In the receive diversity processing module, the multi-path signal is subjected to receive diversity processing, and the receive diversity processing adopts a maximum ratio combining algorithm, and the multi-path signal is combined into one according to the algorithm to offset the multipath interference in the wireless channel;

[0011] S7. Send the signal after receiving diversity processing to the demodulation module after passing through the second digital filter and the synchronization module, and send the demodulated data to the Turbo decoding module for decoding.

[0012] A high-speed frequency hopping anti-interference system based on SIMO multi-channel, comprising a transmitting end and a receiving end;

[0013] The transmitting end comprises:

[0014] A turbo encoding module, used to encode the data to be sent;

[0015] A first time slot control module, configured to send pulses to the framing module according to a frequency hopping pattern;

[0016] A framing module, used for dividing the turbo-encoded data into several groups according to the information input by the first time slot control module, adding a frequency hopping protection sequence and a pilot sequence to each group, and distributing data groups with different frequency information;

[0017] A modulation module, used for sending the data group with assigned frequency information into the modulation module;

[0018] A first digital filter, used for digitally filtering the modulated data;

[0019] A first radio frequency control module, used to transmit the digitally filtered signal to a wireless channel through a single antenna after passing through a DAC, an up-conversion module and a power amplifier;

[0020] The receiving end comprises:

[0021] A multi-channel receiving antenna is used to receive signals separately to obtain multi-channel receiving signals;

[0022] A second time slot control module, used for calculating frequency hopping information and returning it to the second radio frequency control module for frequency control;

[0023] The second radio frequency control module is used to process the multi-channel signals received by the antenna through the down-conversion module, the filter and the amplifier according to the information input by the second time slot control module, and then convert them into digital signals through the ADC and send them to the receiving diversity processing module;

[0024] The receiving diversity processing module uses the maximum ratio combining algorithm to perform receiving diversity processing on multi-path signals, and combines the multi-path signals into one path according to the algorithm, so as to offset the multipath interference in the wireless channel;

[0025] A second digital filter, used for digitally filtering the signal processed by the receiving diversity processing module;

[0026] A synchronization module, used for performing synchronization processing on the signal output by the second digital filter, wherein the synchronization processing refers to determining the frame header of the data according to the pilot sequence added by the transmitting end to the data, so as to locate the starting point of the data;

[0027] A demodulation module, used for demodulating the signal output by the synchronization module;

[0028] The Turbo decoding module is used to decode the demodulated data.

[0029] The beneficial effects of the present invention are as follows: the present invention ensures the stability and reliability of the wireless communication system without increasing the system transmission power consumption, and improves its anti-interference ability in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The antenna design of the communication system is a channel diagram of one transmit and two receive;

[0031] Figure 2 It is a schematic diagram of the principle of the present invention;

[0032] Figure 3 The schematic diagram is a principle diagram of data grouping and modulation;

[0033] Figure 4 This is a schematic diagram of the principle of the Turbo codec module. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0035] It is known that during the transmission of a signal through a wireless channel, the probability that multiple statistically independent fading channels are in deep fading at the same time is very low. Based on this, the anti-interference requirement for multipath fading can be achieved by not changing the number of transmitting antennas but only increasing the number of receiving channels. The antenna design of this communication system is one-transmit and two-receive. The channel diagram is shown in the figure. Figure 1 As shown;

[0036] like Figure 2 As shown, a high-speed frequency hopping anti-interference method based on SIMO multi-channel includes the following steps:

[0037] S1. At the transmitting end of the signal, the data is turbo-encoded and sent to the framing module;

[0038] S2. The framing module divides the turbo-encoded data into several groups according to the information sent by the first time slot control module and adds the frequency number, and then adds the frequency hopping protection sequence and the pilot sequence to each group of data, and then sends it to the modulation module;

[0039] S3. The data group of the allocated frequency information is sent to the modulation module for modulation, and the modulated data is digitally filtered through the first digital filter;

[0040] S4. In the first RF control module, the digitally filtered signal is transmitted to the wireless channel through a single antenna after passing through a DAC, an up-conversion module and a power amplifier;

[0041] S5. At the receiving end, signals are received by multiple receiving antennas respectively, and the second RF control module processes the multiple signals received by the antennas respectively through a down-conversion module, a filter and an amplifier according to the information input by the second time slot control module, and then converts the signals into digital signals through the ADC and sends them to the receiving diversity processing module;

[0042] S6. In the receive diversity processing module, the multi-path signal is subjected to receive diversity processing, and the receive diversity processing adopts a maximum ratio combining algorithm, and the multi-path signal is combined into one according to the algorithm to offset the multipath interference in the wireless channel;

[0043] S7. Send the signal after receiving diversity processing to the demodulation module after passing through the second digital filter and the synchronization module, and send the demodulated data to the Turbo decoding module for decoding.

[0044] In the embodiment of the present application, at the signal receiving end of the signal sent by the transmitting end, the receiving end does not know where the starting point of the signal to be demodulated and decoded is. Only by locating the starting point of the signal can the subsequent demodulation and decoding be correct. Therefore, the synchronization module is required to determine the frame header of the data according to the pilot sequence added by the transmitting end to the data, so as to locate the starting point of the data;

[0045] In the embodiment of the present application, the modulation mode of the modulation module is pi / 4DQPSK, and the filter used for digital filtering in step S4 is a root raised cosine filter with a filter parameter of 0.8. The DAC and ADC are both AD9361, Figure 2 In the figure, two receiving antennas are taken as an example.

[0046] like Figure 3 As shown, step S2 includes:

[0047] S201. The first time slot control module sends a pulse to the framing module at set intervals, each pulse represents a frequency sequence, the frequency hopping sequence changes according to the first time slot control module preset frequency hopping pattern;

[0048] S202. When the framing module receives the pulse from the first time slot control module, the turbo-encoded data is divided into N groups of equal length, and frequency numbers are added to the N groups of data in sequence according to the frequency sequence of the current pulse, each frequency number corresponds to different frequency information in the frequency sequence, and each group of data has a frequency number after adding;

[0049] Each time a pulse is received, N sets of data with frequency numbers added will be obtained until the signal transmitter stops sending data;

[0050] S203. Add the frequency-coded data to the protection sequence and the pilot sequence, and input them into the modulation module in a column of 8 groups for modulation and transmission.

[0051] The step S5 includes:

[0052] When the link is not established, the operating frequency of the second RF control module is always at a fixed frequency. Although the transmitter operates in frequency hopping mode, the clock transmission frequency is always , when the second RF control module receives the signal from the transmitter at a frequency of The signal sent at the second time slot is analyzed and the analyzed frequency information is sent to the second time slot control module. The second time slot control module calculates the next frequency hopping information according to the analyzed frequency information and the preset frequency hopping pattern and returns it to the second RF control module. Finally, the second RF control module controls the frequency change according to the frequency hopping information input by the second time slot control module, so as to process the different frequency information received by the antenna.

[0053] The step S6 performs receive diversity processing on the multi-path signals, and the receive diversity processing module adopts maximum ratio combining, which specifically includes:

[0054] Assumptions The vector of independent fading channels is It can be expressed as:

[0055] ; (1)

[0056] x is the transmitted signal with unit variance, and the received signal It can be expressed as:

[0057] (2)

[0058] Where z is the noise, is the signal power, is the noise power, and the maximum ratio combining algorithm uses the following weighted summation method to Merge the branches:

[0059] ; (3)

[0060] in, represents the merged result of MRC, represents the weight coefficient of the i-th independent fading channel; represents the received signal of the i-th independent fading channel;

[0061] From formula (2), we can see that the combined result Decomposed into useful signal part and noise part:

[0062] (4)

[0063] From the above formula, we know that the instantaneous average power of the signal is The instantaneous average power of the sum noise for:

[0064] (5)

[0065] (6)

[0066] in, It means to find the expected value;

[0067] From equations (5) and (6), we can get the average SNR of MRC:

[0068] ; (7)

[0069] Introduce the inequality:

[0070] ; (8)

[0071] Then the upper limit of (7) is:

[0072] ; (9)

[0073] The SNR in formula (9) is When it reaches its maximum, for The vector of independent fading channels is The closest value of ),Right now When , the MRC effect is optimal.

[0074] This can give the best weighting coefficient , and finally the multiple receiving channels are combined by the following weighted summation method:

[0075] (10)

[0076] Indicates the final merge result. express No.1 in Elements represents the i-th element, .

[0077] A high-speed frequency hopping anti-interference system based on SIMO multi-channel, comprising a transmitting end and a receiving end;

[0078] The transmitting end comprises:

[0079] A turbo encoding module, used to encode the data to be sent;

[0080] A first time slot control module, configured to send pulses to the framing module according to a frequency hopping pattern;

[0081] A framing module, used for dividing the turbo-encoded data into several groups according to the information input by the first time slot control module, adding a frequency hopping protection sequence and a pilot sequence to each group, and distributing data groups with different frequency information;

[0082] A modulation module, used for sending the data group with assigned frequency information into the modulation module;

[0083] A first digital filter, used for digitally filtering the modulated data;

[0084] A first radio frequency control module, used to transmit the digitally filtered signal to a wireless channel through a single antenna after passing through a DAC, an up-conversion module and a power amplifier;

[0085] The receiving end comprises:

[0086] A multi-channel receiving antenna is used to receive signals separately to obtain multi-channel receiving signals;

[0087] A second time slot control module, used for calculating frequency hopping information and returning it to the second radio frequency control module for frequency control;

[0088] The second radio frequency control module is used to process the multi-channel signals received by the antenna through the down-conversion module, the filter and the amplifier according to the information input by the second time slot control module, and then convert them into digital signals through the ADC and send them to the receiving diversity processing module;

[0089] The receiving diversity processing module uses the maximum ratio combining algorithm to perform receiving diversity processing on multi-path signals, and combines the multi-path signals into one path according to the algorithm, so as to offset the multipath interference in the wireless channel;

[0090] A second digital filter, used for digitally filtering the signal processed by the receiving diversity processing module;

[0091] A synchronization module, used for performing synchronization processing on the signal output by the second digital filter, wherein the synchronization processing refers to determining the frame header of the data according to the pilot sequence added by the transmitting end to the data, so as to locate the starting point of the data;

[0092] A demodulation module, used for demodulating the signal output by the synchronization module;

[0093] The Turbo decoding module is used to decode the demodulated data.

[0094] In the embodiment of the present application, the Turbo decoding module adopts a multi-dimensional joint anti-interference design in the frequency domain and the code domain. High-speed frequency hopping (greater than 20,000 hops / second) is adopted in the frequency domain, and high-performance low-code rate Turbo coding is adopted in the code domain. This solution uses one data block to allocate 8 frequency points for transmission, which can resist 40% of frequency interference, such as Figure 4 As shown; the Turbo decoding module outputs valid data and reports the error status of the group of data.

[0095] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, it is still possible for a person skilled in the art to modify the methods described in the above embodiments, such as changing the names of the methods, etc. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high-speed frequency hopping anti-interference method based on SIMO multi-channel, characterized in that: The following steps are involved: S1. At the transmitting end of the signal, the data is turbo-encoded and sent to the framing module; S2. The framing module divides the turbo-encoded data into several groups according to the information sent by the first time slot control module and adds the frequency number, and then adds the frequency hopping protection sequence and the pilot sequence to each group of data, and then sends it to the modulation module; S3. The data group of the allocated frequency information is sent to the modulation module for modulation, and the modulated data is digitally filtered through the first digital filter; S4. In the first RF control module, the digitally filtered signal is transmitted to the wireless channel through a single antenna after passing through a DAC, an up-conversion module and a power amplifier; S5. At the receiving end, signals are received by multiple receiving antennas respectively, and the second RF control module processes the multiple signals received by the antennas respectively through a down-conversion module, a filter and an amplifier according to the information input by the second time slot control module, and then converts the signals into digital signals through the ADC and sends them to the receiving diversity processing module; S6. In the receive diversity processing module, the multi-path signal is subjected to receive diversity processing, and the receive diversity processing adopts a maximum ratio combining algorithm, and the multi-path signal is combined into one according to the algorithm to offset the multipath interference in the wireless channel; The step S6 performs receive diversity processing on the multi-path signals. The receive diversity processing module adopts the maximum ratio combining algorithm, referred to as MRC, which specifically includes: Assumptions The vector of independent fading channels is It is expressed as: ； （1） in, Respectively represent the 1st to Independent fading channels for each receive channel, Indicates the total number of receiving channels, that is, the number of multi-channel signals; x is the transmitted signal with unit variance, and the received signal It is expressed as: ； （2） Where z is the received noise, is the signal power, is the noise power, and the following MRC weighted summation method is used to Merge the branches: ； （3） in, represents the merged result of MRC, represents the weight coefficient of the i-th independent fading channel; represents the received signal of the i-th independent fading channel, MRC is the maximum ratio combining algorithm; From formula (2), we can get the combined result Decomposed into useful signal part and noise part: ； （4） in is the useful signal part after decomposition, is the noise part after decomposition, is the weight vector to be obtained, To receive noise; From the above formula, we know that the instantaneous average power of the signal is The instantaneous average power of the sum noise for: （5） （6） in, It means to find the expected value; The average SNR of MRC is obtained from equations (5) and (6) and is denoted as : ；（7） Introduce the inequality: （8） Then the upper limit of (7) is: ； （9） The SNR in formula (9) is When it reaches its maximum, for The vector of independent fading channels is The closest value of ,Right now When , the maximum ratio combining algorithm achieves the best effect, thus obtaining the best weighting coefficient , and finally the multiple receiving channels are combined by the following weighted summation method: (10) Indicates the final merge result. express No.1~ elements, represents the i-th element, ; S7. Send the signal after receiving diversity processing to the demodulation module after passing through the second digital filter and the synchronization module, and send the demodulated data to the Turbo decoding module for decoding.

2. The high-speed frequency hopping anti-interference method based on SIMO multi-channel according to claim 1 is characterized in that: The modulation mode of the modulation module is pi / 4DQPSK.

3. The high-speed frequency hopping anti-interference method based on SIMO multi-channel according to claim 1 is characterized in that: The filter used for digital filtering in step S4 is a root raised cosine filter.

4. The high-speed frequency hopping anti-interference method based on SIMO multi-channel according to claim 1 is characterized in that: The step S2 comprises: S201. The first time slot control module sends a pulse to the framing module at set intervals, each pulse represents a frequency sequence, the frequency hopping sequence changes according to the first time slot control module preset frequency hopping pattern; S202. When the framing module receives the pulse from the first time slot control module, the turbo-encoded data is divided into N groups of equal length, and frequency numbers are added to the N groups of data in sequence according to the frequency sequence of the current pulse, each frequency number corresponds to different frequency information in the frequency sequence, and each group of data has a frequency number after adding; Each time a pulse is received, N sets of data with frequency numbers added will be obtained until the signal transmitter stops sending data; S203. Add the frequency-coded data to the protection sequence and the pilot sequence, and input them into the modulation module in a column of 8 groups for modulation and transmission.

5. The high-speed frequency hopping anti-interference method based on SIMO multi-channel according to claim 1 is characterized in that: The step S5 comprises: When the link is not established, the operating frequency of the second RF control module is always at a fixed frequency. Although the transmitter operates in frequency hopping mode, the clock transmission frequency is always , when the second RF control module receives the signal from the transmitter at a frequency of The signal sent at the second time slot is analyzed and the analyzed frequency information is sent to the second time slot control module. The second time slot control module calculates the next frequency hopping information according to the analyzed frequency information and the preset frequency hopping pattern and returns it to the second RF control module. Finally, the second RF control module controls the frequency change according to the frequency hopping information input by the second time slot control module, and processes the multi-path signals received by the antenna through the down-conversion module, the filter and the amplifier respectively, and then converts them into digital signals through the ADC and sends them to the receive diversity processing module.

6. A high-speed frequency hopping anti-interference system based on SIMO multi-channel, based on the method described in any one of claims 1 to 5, characterized in that: Includes the sending end and the receiving end; The transmitting end comprises: A turbo encoding module, used to encode the data to be sent; A first time slot control module, configured to send pulses to the framing module according to a frequency hopping pattern; A framing module, used for dividing the turbo-encoded data into several groups according to the information input by the first time slot control module, adding a frequency hopping protection sequence and a pilot sequence to each group, and distributing data groups with different frequency information; A modulation module, used for sending the data group with assigned frequency information into the modulation module; A first digital filter, used for digitally filtering the modulated data; A first radio frequency control module, used to transmit the digitally filtered signal to a wireless channel through a single antenna after passing through a DAC, an up-conversion module and a power amplifier; The receiving end comprises: A multi-channel receiving antenna is used to receive signals separately to obtain multi-channel receiving signals; A second time slot control module, used for calculating frequency hopping information and returning it to the second radio frequency control module for frequency control; The second radio frequency control module is used to process the multi-channel signals received by the antenna through the down-conversion module, the filter and the amplifier according to the information input by the second time slot control module, and then convert them into digital signals through the ADC and send them to the receiving diversity processing module; The receiving diversity processing module uses the maximum ratio combining algorithm to perform receiving diversity processing on multi-path signals, and combines the multi-path signals into one path according to the algorithm, so as to offset the multipath interference in the wireless channel; A second digital filter, used for digitally filtering the signal processed by the receiving diversity processing module; A synchronization module, used for performing synchronization processing on the signal output by the second digital filter, wherein the synchronization processing refers to determining the frame header of the data according to the pilot sequence added by the transmitting end to the data, so as to locate the starting point of the data; A demodulation module, used for demodulating the signal output by the synchronization module; The Turbo decoding module is used to decode the demodulated data.

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