Voice-like modulation and demodulation method and device

Abstract

The present invention provides a voice-like modulation and demodulation method and device, which relates to the field of voice communication technology. The method includes: controlling a first user terminal and a second user terminal to perform differential phase modulation on encrypted voice signals to be sent based on different modulation frequencies, and transmitting the modulated voice signals to the other user terminal after time domain conversion; when it is determined that the second user terminal receives the first type of voice data symbol sent by the first user terminal, controlling the second user terminal to perform differential phase demodulation on the first type of voice data symbol; when it is determined that the first user terminal receives the second type of voice data symbol sent by the second user terminal, controlling the first user terminal to perform differential phase demodulation on the second type of voice data symbol. The present invention generates a voice-like signal with time-frequency characteristics by performing differential phase modulation on the encrypted voice signal, and realizes full-duplex voice communication through a modulation and demodulation method with staggered frequencies.

Description

Technical Field

[0001] The present invention relates to the field of voice communication technology, and in particular to a voice-like modulation and demodulation method and device. Background Art

[0002] In traditional voice transmission systems, in order to save transmission channel bandwidth, voice signals are usually compressed and encoded using a vocoder. Since the compressed and encoded voice signal no longer has voice characteristics after digital encryption, the vocoder cannot extract the basic characteristics of the voice signal from it, or it will be treated as noise. Therefore, it is necessary to transform the encrypted voice signal into a voice-like signal with voice characteristics, so as to achieve encrypted transmission on the voice channel.

[0003] The existing quasi-speech algorithm has a good simulation effect, but in the actual environment, hardware deviations and the voice enhancement processing of the communication software will have a great impact on the quasi-speech signal, resulting in a high bit error rate. In addition, the existing voice communication software usually performs voice detection on the calls of the two communicating parties. If the voices of the two parties are similar, the voice of one party will be suppressed, and only half-duplex communication can be achieved. In addition, the voice enhancement technology used in the existing voice communication software has a great impact on the amplitude of the voice signal, causing a large distortion of the amplitude of the voice signal, but has little effect on the phase of the voice signal.

[0004] Taking the above into consideration, the industry urgently needs to design a voice-like modulation and demodulation scheme based on phase modulation to transform the encrypted voice signal into a voice-like signal with certain time-frequency characteristics, so as to achieve the purpose of full-duplex communication in the actual voice channel. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a speech-like modulation and demodulation method and device.

[0006] In a first aspect, the present invention provides a speech-like modulation and demodulation method, comprising:

[0007] Determine a first encrypted voice signal to be sent by a first user terminal and a second encrypted voice signal to be sent by a second user terminal;

[0008] Control the first user terminal to perform differential phase modulation on the first encrypted voice signal based on a first modulation frequency and a first modulation order, obtain a first frequency domain voice signal, perform time domain conversion on the first frequency domain voice signal, obtain a first type of voice data symbol, and transmit the first type of voice data symbol to the second user terminal;

[0009] Control the second user terminal to perform differential phase modulation on the second encrypted voice signal based on the second modulation frequency and the first modulation order, obtain a second frequency domain voice signal, perform time domain conversion on the second frequency domain voice signal, obtain a second type of voice data symbol, and transmit the second type of voice data symbol to the first user terminal;

[0010] When it is determined that the second user terminal receives the first type of voice data symbol, control the second user terminal to perform differential phase demodulation on the first type of voice data symbol based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data;

[0011] When it is determined that the first user terminal receives the second-category voice data symbol, controlling the first user terminal to perform differential phase demodulation on the second-category voice data symbol based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data;

[0012] Among them, the first modulation frequency is different from the second modulation frequency, the first modulation frequency is the same as the first demodulation frequency, the second modulation frequency is the same as the second demodulation frequency, and the first modulation order is the same as the first demodulation order.

[0013] Optionally, according to a voice-like modulation and demodulation method provided by the present invention, transmitting the first-class voice data symbol to a second user terminal includes:

[0014] Control the first user terminal to perform differential phase modulation on the first control information required for key synchronization based on the first modulation frequency and the second modulation order, and perform time domain conversion on the first frequency domain control signal obtained after modulation to obtain a first time domain control signal;

[0015] Combining the first synchronization signal of the first user terminal and the first time domain control signal into a first preamble symbol;

[0016] The first blank symbol, the first leading symbol and the first type of voice data symbol form a first type of voice signal frame;

[0017] Control the first user terminal to transmit the first type of voice signal frame to the second user terminal.

[0018] Optionally, according to a voice-like modulation and demodulation method provided by the present invention, controlling the second user terminal to perform differential phase demodulation on the first-like voice data symbol based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data includes:

[0019] Control the second user terminal to perform frame synchronization on the first type of voice signal frame based on the first blank symbol and the first leading symbol in the received first type of voice signal frame, determine a first starting position of the first leading symbol, and determine a first type of voice data symbol in the first type of voice signal frame based on the first starting position;

[0020] Control the second user terminal to perform differential phase demodulation on the first type of voice data symbols based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data.

[0021] Optionally, according to a speech-like modulation and demodulation method provided by the present invention, after determining the first starting position of the first leading symbol, the method further includes:

[0022] Controlling the second user terminal to determine a first time domain control signal in the first type of voice signal frame based on the first starting position;

[0023] Control the second user terminal to perform differential phase demodulation on the first time domain control signal based on the first demodulation frequency point and the second demodulation order to obtain first control information, and decrypt and compress and decode the first demodulated voice data based on the first control information to obtain first original voice data.

[0024] Optionally, according to a voice-like modulation and demodulation method provided by the present invention, transmitting the second-class voice data symbol to the first user terminal includes:

[0025] Control the second user terminal to perform differential phase modulation on the second control information required for key synchronization based on the second modulation frequency and the second modulation order, and perform time domain conversion on the second frequency domain control signal obtained after modulation to obtain a second time domain control signal;

[0026] Combining the second synchronization signal of the second user terminal and the second time domain control signal into a second preamble symbol;

[0027] The second blank symbol, the second leading symbol and the second type of voice data symbol form a second type of voice signal frame;

[0028] Control the second user terminal to transmit the second type of voice signal frame to the first user terminal.

[0029] Optionally, according to a voice-like modulation and demodulation method provided by the present invention, controlling the first user terminal to perform differential phase demodulation on the second-class voice data symbol based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data includes:

[0030] Control the first user terminal to perform frame synchronization on the second-class voice signal frame based on the second blank symbol and the second leading symbol in the received second-class voice signal frame, determine the second starting position of the second leading symbol, and determine the second-class voice data symbol in the second-class voice signal frame based on the second starting position;

[0031] Control the first user terminal to perform differential phase demodulation on the second type of voice data symbols based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data.

[0032] Optionally, according to a speech-like modulation and demodulation method provided by the present invention, after determining the second starting position of the second leading symbol, the method further includes:

[0033] Controlling the first user terminal to determine a second time domain control signal in the second type of voice signal frame based on the second starting position;

[0034] Control the first user terminal to perform differential phase demodulation on the second time domain control signal based on the second demodulation frequency point and the second demodulation order to obtain second control information, and decrypt and compress and decode the second demodulated voice data based on the second control information to obtain second original voice data.

[0035] Optionally, according to a speech-like modulation and demodulation method provided by the present invention, the second modulation order is less than or equal to the first modulation order.

[0036] In a second aspect, the present invention further provides a speech-like modulation and demodulation device, comprising:

[0037] A determination module, used to determine a first encrypted voice signal to be sent by a first user terminal and a second encrypted voice signal to be sent by a second user terminal;

[0038] A first control module, used to control the first user terminal to perform differential phase modulation on the first encrypted voice signal based on a first modulation frequency and a first modulation order, obtain a first frequency domain voice signal, perform time domain conversion on the first frequency domain voice signal, obtain a first type of voice data symbol, and transmit the first type of voice data symbol to a second user terminal;

[0039] A second control module, used to control the second user terminal to perform differential phase modulation on the second encrypted voice signal based on a second modulation frequency and a first modulation order, obtain a second frequency domain voice signal, perform time domain conversion on the second frequency domain voice signal, obtain a second type of voice data symbol, and transmit the second type of voice data symbol to the first user terminal;

[0040] A third control module is used to control the second user terminal to perform differential phase demodulation on the first type of voice data symbol based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data when it is determined that the second user terminal receives the first type of voice data symbol;

[0041] a fourth control module, configured to control the first user terminal to perform differential phase demodulation on the second type of voice data symbols based on a second demodulation frequency point and a first demodulation order to obtain second demodulated voice data when it is determined that the first user terminal receives the second type of voice data symbols;

[0042] Among them, the first modulation frequency is different from the second modulation frequency, the first modulation frequency is the same as the first demodulation frequency, the second modulation frequency is the same as the second demodulation frequency, and the first modulation order is the same as the first demodulation order.

[0043] In a third aspect, the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the speech-like modulation and demodulation method as described in the first aspect is implemented.

[0044] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the speech-like modulation and demodulation method as described in the first aspect.

[0045] In a fifth aspect, the present invention further provides a computer program product, comprising a computer program, which, when executed by a processor, implements the speech-like modulation and demodulation method as described in the first aspect.

[0046] The voice-like modulation and demodulation method and device provided by the present invention controls the first user terminal and the second user terminal to perform differential phase modulation on the encrypted voice signal based on different modulation frequencies, thereby generating a voice-like signal with time-frequency characteristics, and controls the first user terminal and the second user terminal to transmit the voice-like signals generated by each terminal to the communication counterpart and then perform differential phase demodulation. This can not only effectively avoid the influence of hardware deviations of the communication terminal and voice enhancement processing, but also realize full-duplex voice communication based on this frequency-interleaved modulation and demodulation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 It is a flow chart of the voice-like modulation and demodulation method provided by the present invention;

[0049] Figure 2 It is a schematic diagram of the process of differential phase modulation provided by the present invention;

[0050] Figure 3 is a phase diagram of a voice-like signal after modulation by a first user terminal provided by the present invention;

[0051] Figure 4 is a phase diagram of a voice-like signal after modulation by a second user terminal provided by the present invention;

[0052] Figure 5 It is a phase diagram of a full-duplex aliasing voice signal provided by the present invention;

[0053] Figure 6 It is a schematic diagram of the process of differential phase demodulation provided by the present invention;

[0054] Figure 7 It is a schematic diagram of the time domain waveform of the synchronization signal provided by the present invention;

[0055] Figure 8 It is a structural schematic diagram of a 400ms-like speech signal frame provided by the present invention;

[0056] Fig. 9 It is a schematic diagram of the synchronization process of the voice-like signal frame provided by the present invention;

[0057] Fig.10 It is a schematic diagram of a rough synchronization result based on energy detection provided by the present invention;

[0058] Fig.11 is a schematic diagram of a fine synchronization result based on cross-correlation provided by the present invention;

[0059] Fig.12 It is a schematic diagram of the working process of the full-duplex voice system provided by the present invention;

[0060] Fig.13 It is a structural schematic diagram of the voice-like modulation and demodulation device provided by the present invention;

[0061] Fig.14 It is a schematic diagram of the physical structure of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] In order to facilitate a clearer understanding of the embodiments of the present invention, some relevant background knowledge is first introduced as follows.

[0064] Voice communication has been widely used in our daily life, but voice communication eavesdropping incidents happen from time to time. For example, after installing a Trojan on a mobile phone, it is easy to eavesdrop on the user's conversation through a wireless network. If the voice can be encrypted before it is transmitted, it can prevent third-party eavesdropping during subsequent voice processing and voice transmission.

[0065] In traditional voice transmission systems, in order to save transmission channel bandwidth, a vocoder is used to compress and encode the voice. Most vocoders use a hybrid parameter coding algorithm to process and model the voice, and extract the model parameters for transmission. The compressed and encoded voice signal will no longer have voice characteristics after digital encryption. After passing through the vocoder, the basic characteristics of the voice signal cannot be extracted, or it is treated as noise, making it difficult to effectively transmit through the voice channel. Therefore, it is necessary to further process the encrypted voice signal and transform it into a voice-like signal with voice characteristics, so as to achieve encrypted transmission on the language channel.

[0066] The existing quasi-speech algorithms have good simulation effects, but in actual environments, hardware deviations and the voice enhancement processing of communication software will have a great impact on quasi-speech signals, resulting in poor effects and high bit error rates when these voice enhancement algorithms are used in various voice communication software. For example, due to differences in the crystal oscillator accuracy of the sound cards of the sender and receiver, the quasi-speech modulated data will have a frequency offset during the transmission process, resulting in errors in the demodulation of the quasi-speech data. In addition, existing voice communication software usually performs voice detection on the calls of the two communicating parties. If the voices of both parties are similar, one of them will be treated as an echo, that is, the voice of one party will be suppressed, and only half-duplex communication can be achieved. In addition, the voice enhancement technology used in existing voice communication software has a greater impact on the amplitude of the voice signal, resulting in a large distortion of the amplitude of the voice signal, but has less impact on the phase of the voice signal.

[0067] In order to overcome the above-mentioned defects, the present invention provides a method and device for modulating and demodulating speech-like signals. Figure 1-Figure 14 The present invention describes the speech-like modulation and demodulation method and device.

[0068] Figure 1 Schematic diagram of the flow of the voice-like modulation and demodulation method provided by the present invention, such as Figure 1 As shown, the method includes:

[0069] Step 100: determining a first encrypted voice signal to be sent by a first user terminal and a second encrypted voice signal to be sent by a second user terminal.

[0070] Specifically, the first user terminal and the second user terminal can respectively use their own sound cards based on a preset sampling rate f s Voice data of a preset duration (t seconds) is collected, and then voice activity detection is performed on the collected voice data to identify valid voice data, and each segment of valid voice data is further compressed and encoded according to the voice transmission bit rate (r) to obtain m bits of voice data and then encrypt it, so that a first encrypted voice signal to be sent by the first user terminal and a second encrypted voice signal to be sent by the second user terminal can be obtained.

[0071] For example, the first user terminal and the second user terminal respectively use their own USB sound cards to collect 20 milliseconds of voice data at a sampling rate of 8kHz, that is, 160 sampling points (the collection time of the voice data can be set according to the output length requirement of the compression encoding algorithm selected subsequently), and then use the voice activity detection algorithm in WebRTC (Web Real-Time Communications) to perform voice activity detection on the collected voice data. If it is valid voice data, the frame of voice data is saved for subsequent processing, otherwise a blank signal of all zeros is output.

[0072] Furthermore, the 20ms effective voice data obtained above can be compressed and encoded by Codec2 according to the voice transmission bit rate r=2.4kbps to obtain m=r×t=48 bits of voice data, and the compression ratio of the compression coding is 160÷48=3.33. Then, the m-bit voice data is encrypted using the 256-bit Zu Chongzhi's Cipher-256 (ZUC-256) stream encryption algorithm to obtain the first encrypted voice signal to be sent by the first user terminal and the second encrypted voice signal to be sent by the second user terminal.

[0073] Step 110, control the first user terminal to perform differential phase modulation on the first encrypted voice signal based on a first modulation frequency and a first modulation order, obtain a first frequency domain voice signal, perform time domain conversion on the first frequency domain voice signal, obtain first type of voice data symbols, and transmit the first type of voice data symbols to the second user terminal.

[0074] Specifically, the first user terminal can be controlled to perform differential phase modulation on the first encrypted voice signal determined in step 100 based on the first modulation frequency and the first modulation order, obtain a first frequency domain voice signal, and after performing time domain conversion on the first frequency domain voice signal, the obtained first type of voice data symbols can be transmitted to the second user terminal.

[0075] Step 120, control the second user terminal to perform differential phase modulation on the second encrypted voice signal based on the second modulation frequency and the first modulation order, obtain a second frequency domain voice signal, perform time domain conversion on the second frequency domain voice signal, obtain second type voice data symbols, and transmit the second type voice data symbols to the first user terminal.

[0076] Specifically, the second user terminal can be controlled to perform differential phase modulation on the second encrypted voice signal determined in step 100 based on the second modulation frequency and the first modulation order, obtain a second frequency domain voice signal, and after performing time domain conversion on the second frequency domain voice signal, the obtained second type of voice data symbols can be transmitted to the first user terminal.

[0077] Optionally, the first modulation frequency selected by the first user terminal when performing differential phase modulation on the first encrypted voice signal is different from the second modulation frequency selected by the second user terminal when performing differential phase modulation on the second encrypted voice signal, thereby realizing a frequency-interleaved modulation method.

[0078] For example, the first user terminal and the second user terminal may perform two operations on the encrypted voice data in the frequency domain respectively. k The first user terminal and the second user terminal each select N f +1 frequency point for modulation, for example, the initial frequency point selected by the first user terminal is f a , the initial frequency point selected by the second user terminal is f b =f a +Δf, then the frequency point used by the first user terminal is f a +i×2×Δf(0≤i≤N f ), the frequency point used by the second user terminal is f a +(i×2+1)×Δf(0≤i≤N f ), so the two choices are 2×(N f +1) frequency points are staggered, so even if the voice-like signals are mixed together, they can be effectively separated to achieve the effect of full-duplex communication.

[0079] Optionally, the first user terminal and the second user terminal respectively select N f +1 frequency point for 2 kOrder differential phase modulation, every two adjacent frequency points with an interval of 2×Δf are a group, each containing N f group, k bits of data are mapped into 2 k An optional differential phase parameter, as the phase difference between adjacent frequency points, the initial frequency point f a and f b Fixed phase modulation is used.

[0080] After completing the frequency domain differential phase modulation, the first user terminal and the second user terminal may respectively convert the modulated frequency domain signal into the time domain through Inverse Fast Fourier Transform (IFFT) to obtain a speech-like modulated time domain data symbol.

[0081] Figure 2 is a schematic diagram of the differential phase modulation process provided by the present invention, such as Figure 2 As shown, the first user terminal and the second user terminal can be based on Figure 2 The process shown performs 4th-order differential phase modulation (Differential Quadrature Phase Shift Keying, DQPSK) in the frequency domain, and selects 16 frequency points in the modulation frequency range of 300 Hz to 3400 Hz for modulation. For example, the initial frequency point selected by the first user terminal is 300 Hz, and the initial frequency point selected by the second user terminal is 400 Hz. Both parties select the same fundamental frequency (minimum frequency interval) of 100 Hz, so the frequency point selected by the first user terminal is 300+200×i (0≤i≤15), and the frequency point selected by the second user terminal is 400+200×i (0≤i≤15). In this way, the 32 frequency points selected by the two are staggered, and the voice-like signals can be effectively separated even after being mixed together, thereby achieving the effect of full-duplex communication.

[0082] In the embodiment of the present invention, the first user terminal and the second user terminal respectively use a fixed phase of 0 for modulation at the initial frequency points of 300 Hz and 400 Hz, and select two adjacent frequency points with an interval of 200 Hz as a group, each of which contains 15 groups, that is, the first user terminal is modulated based on 15 groups of adjacent frequency points including {(300, 500), (500, 700), ..., (3100, 3300)}, and the second user terminal is modulated based on 15 groups of adjacent frequency points including {(400, 600), (600, 800), ..., (3200, 3400)}, and each group of frequency points modulates 2 bits of data. The mapping method of Gray coding is used to reduce the bit error rate. The mapping relationship between the modulation bit of the encrypted voice signal and the differential phase of the adjacent frequency points is shown in Table 1:

[0083] Table 1 Mapping relationship between modulation bits of encrypted speech signal and differential phase of adjacent frequency points

[0084] 2-bit data 00 10 11 01 DQPSK Differential Phase 0 π / 2 π -π / 2

[0085] Figure 3 is a phase diagram of a voice-like signal after modulation by a first user terminal provided by the present invention, Figure 4 is a phase diagram of a voice-like signal after modulation by a second user terminal provided by the present invention, such as Figure 3 and Figure 4 As shown, the phase diagram is shown after the first user terminal and the second user terminal perform DQPSK modulation on 30-bit data {1 0 0 1 1 1 0 0 1 0 1 0 0 1 1 1 0 0 1 0 10 0 1 1 1 0 0 1 0} respectively. When the first user terminal and the second user terminal perform full-duplex communication, the transmitted signals will be mixed together. Figure 5 Schematic diagram of the phase of the full-duplex aliasing speech signal provided by the present invention, such as Figure 5 As shown, the solid line represents the phase part of the first user terminal, and the dotted line represents the phase part of the second user terminal. Figure 5 It can be seen that the frequency points occupied by the signals of the first user terminal and the second user terminal are interlaced and will not cause interference.

[0086] In the embodiment of the present invention, after the frequency domain differential phase modulation is completed for the above 30-bit encrypted data, the modulated frequency domain signal can be converted to the time domain through the inverse fast Fourier transform to obtain a voice-like data symbol with a length of 1 / 100 Hz = 10 ms. Therefore, a 20 ms voice-like data symbol can carry 60 bits of encrypted data.

[0087] Step 130, when it is determined that the second user terminal receives the first type of voice data symbols, control the second user terminal to perform differential phase demodulation on the first type of voice data symbols based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data.

[0088] Specifically, when it is determined that the second user terminal has received the first type of voice data symbols transmitted by the first user terminal, the second user terminal can be controlled to perform differential phase demodulation on the first type of voice data symbols based on the first demodulation frequency point and the first demodulation order to obtain first demodulated voice data, wherein the first demodulation frequency point is the same as the first modulation frequency point, and the first demodulation order is the same as the first modulation order.

[0089] Step 140, when it is determined that the first user terminal receives the second type of voice data symbols, control the first user terminal to perform differential phase demodulation on the second type of voice data symbols based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data.

[0090] Specifically, when it is determined that the first user terminal has received the second type of voice data symbols transmitted by the second user terminal, the first user terminal can be controlled to perform differential phase demodulation on the second type of voice data symbols based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data, wherein the second demodulation frequency point is the same as the second modulation frequency point, and the first demodulation order is the same as the first modulation order.

[0091] For example, the first user terminal and the second user terminal respectively convert the first type of voice data symbols and the second type of voice data symbols in the time domain into the frequency domain through Fourier transform. k The first user terminal selects the initial frequency point f b =f a +Δf, the initial frequency point selected by the second user terminal is f a , the fundamental frequency is Δf, that is, the frequency used by the first user terminal for demodulation is the frequency used by the second user terminal for modulation: f a +(i×2+1)×Δf(0≤i≤N f ), the frequency point used for demodulation by the second user terminal is the frequency point used by the first user terminal for modulation: f a +i×2×Δf(0≤i≤N f ), the first user terminal and the second user terminal perform 2 k Order differential phase demodulation is performed to obtain demodulated voice data.

[0092] Figure 6 The present invention provides a flow chart of differential phase demodulation. For 16 speech-like data symbols of 320ms, the following can be used: Figure 6 The process shown in the figure selects 10ms length class voice data symbols in turn and transforms them into the frequency domain for 4th order differential phase demodulation to obtain 30 bits of data. During demodulation, the first user terminal demodulates according to the modulation parameters of the second user terminal, and the second user terminal demodulates according to the modulation parameters of the first user terminal, that is, the initial demodulation frequency selected by the first user terminal is 400Hz, and the initial demodulation frequency selected by the second user terminal is 300Hz. The first user terminal calculates the differential phase of every two adjacent frequency points with an interval of 200Hz on the 400+200×i (0≤i≤15) frequency points, and the second user terminal calculates the differential phase of every two adjacent frequency points with an interval of 200Hz on the 300+200×i (0≤i≤15) frequency points. The mapping relationship between the differential phase of adjacent frequency points and the 2-bit data obtained by demodulation is shown in Table 2:

[0093] Table 2 Mapping relationship between differential phase of adjacent frequency points and 2-bit DQPSK demodulation data

[0094]

[0095] Each 10ms voice data symbol can demodulate 30 bits of encrypted voice data, so a total of 960 bits of encrypted voice data can be demodulated from a 320ms data symbol.

[0096] Specifically, in order to overcome the defects of the prior art that hardware deviations and voice enhancement processing of communication software will have a great impact on quasi-voice signals, and can only achieve half-duplex communication when the voices of both parties are similar, the present invention modulates the encrypted voice signals to be sent by the communicating parties through a differential phase modulation method to generate a quasi-voice signal with general voice signal parameter characteristics, which can effectively resist the influence of hardware deviations of the sound cards of the communicating parties and the voice enhancement processing of the actual voice communication software, and realizes full-duplex encrypted communication by staggered frequencies, and can be widely used in confidential communication of end-to-end voice channels.

[0097] The voice-like modulation and demodulation method provided by the present invention controls the first user terminal and the second user terminal to perform differential phase modulation on the encrypted voice signal based on different modulation frequencies, thereby generating a voice-like signal with time-frequency characteristics, and controls the first user terminal and the second user terminal to transmit the voice-like signals generated by each terminal to the communication counterpart and then perform differential phase demodulation. This method can not only effectively avoid the influence of hardware deviation of the communication terminal and voice enhancement processing, but also realize full-duplex voice communication based on this frequency-interleaved modulation and demodulation method.

[0098] Optionally, transmitting the first-category voice data symbol to a second user terminal includes:

[0099] Control the first user terminal to perform differential phase modulation on the first control information required for key synchronization based on the first modulation frequency and the second modulation order, and perform time domain conversion on the first frequency domain control signal obtained after modulation to obtain a first time domain control signal;

[0100] Combining the first synchronization signal of the first user terminal and the first time domain control signal into a first preamble symbol;

[0101] The first blank symbol, the first leading symbol and the first type of voice data symbol form a first type of voice signal frame;

[0102] Control the first user terminal to transmit the first type of voice signal frame to the second user terminal.

[0103] It can be understood that in order to facilitate the transmission of the encrypted voice signal to the communication counterpart, the encrypted voice signal can be decrypted at the communication counterpart. Therefore, in an embodiment of the present invention, when the first user terminal transmits the first type of voice data symbol to the second user terminal, the first user terminal will also transmit the first control information required for key synchronization to the second user terminal, and in order to ensure the continuity of the signal, a first blank symbol is added to the transmitted first type of voice signal frame.

[0104] Specifically, the first user terminal can be first controlled to perform differential phase modulation on the first control information required for key synchronization based on the first modulation frequency and the second modulation order, and perform time domain conversion on the first frequency domain control signal obtained after modulation to obtain a first time domain control signal; then the first synchronization signal and the first time domain control signal of the first user terminal are combined into a first leading symbol; further, the first blank symbol, the first leading symbol and the first type of voice data symbol are combined into a first type of voice signal frame; finally, the first user terminal is controlled to transmit the first type of voice signal frame to the second user terminal.

[0105] It can be understood that the first control information required for key synchronization is allocated to the first user terminal by a dedicated key distribution center, and the first control information required for key synchronization is used by the second user terminal to decrypt the encrypted voice signal sent by the first user terminal.

[0106] It can be understood that in the embodiment of the present invention, in order to ensure that the clocks of the sender (first user terminal) and the receiver (second user terminal) are unified, and the transmission of characters is synchronous and without intervals, the first user terminal is controlled to generate a first synchronization signal, and the first user terminal is controlled to transmit the first synchronization signal together with the voice-like data to be transmitted to the second user terminal. The first synchronization signal is used to notify the second user terminal that a data frame has arrived, and ensure that the sampling speed of the second user terminal and the bit arrival speed are consistent, so that the first user terminal and the second user terminal are synchronized.

[0107] Optionally, in an embodiment of the present invention, in order to ensure signal continuity, a first blank symbol is added to the first type of voice signal frame sent by the first user terminal, wherein the length of the first blank symbol can be determined based on the first type of voice signal frame actually transmitted.

[0108] Optionally, the first blank symbol added to the first type of speech signal frame may be an all-zero signal.

[0109] It can be understood that, in the embodiment of the present invention, by adding the first blank symbol in the first type of voice signal frame sent by the first user terminal, the continuous transmission of the voice-like signal in the voice communication channel can be ensured.

[0110] Optionally, in an embodiment of the present invention, the first user terminal can be controlled to perform differential phase modulation on the first control information required for key synchronization based on a first modulation frequency and a second modulation order, wherein the second modulation order can be the same as the first modulation order or different from the first modulation order, and the embodiment of the present invention does not specifically limit the size of the second modulation order.

[0111] For example, the first user terminal performs 2 in the frequency domain on the first control information required for key synchronization. p The first frequency domain control signal is modulated by differential phase modulation, and then the modulated first frequency domain control signal is converted into the time domain to obtain a first time domain control signal, and the first synchronization signal of the first user terminal and the first time domain control signal are further combined into a first leading symbol.

[0112] Optionally, the first user terminal may perform similar voice-like modulation on the first control information required for key synchronization according to the method of modulating the first encrypted voice signal.

[0113] Optionally, in an embodiment of the present invention, in order to reduce the bit error rate and ensure the correct transmission of control information, the modulation order p of the first control information required for key synchronization can be less than or equal to the modulation order k of the first encrypted voice signal, that is, the second modulation order is less than or equal to the first modulation order.

[0114] Optionally, after completing the frequency domain differential phase modulation of the first control information, the first user terminal can convert the modulated first frequency domain control signal to the time domain through an inverse fast Fourier transform to obtain a first time domain control signal of voice-like modulation, and then combine the first synchronization signal of the first user terminal and the first time domain control signal into a first leading symbol.

[0115] For example, the first user terminal performs cyclic redundancy check (CRC) encoding with a code rate of 2 / 3 on 10-bit control information (including a 2-bit key number and an 8-bit frame number) required for key synchronization, and can obtain encoded 15-bit control information.

[0116] Optionally, in an embodiment of the present invention, the first user terminal may perform second-order differential phase modulation (DBPSK) on the encoded 15-bit control information in the frequency domain. The frequency selection and the initial frequency modulation phase are the same as the modulation of the first encrypted voice signal, but each group of adjacent frequencies only modulates 1 bit of data. The mapping relationship between the modulation bit of the control information and the differential phase of the adjacent frequencies is shown in Table 3:

[0117] Table 3 Mapping relationship between modulation bits of control information and differential phases of adjacent frequency points

[0118] 1 bit of data 0 1 DBPSK Differential Phase 0 π

[0119] Optionally, after frequency domain differential phase modulation is completed on the encoded 15-bit control information, the modulated frequency domain signal may be converted to the time domain by inverse fast Fourier transform to obtain 10 ms speech-like modulated control information.

[0120] Figure 7 The schematic diagram of the time domain waveform of the synchronization signal provided by the present invention can be used to combine the control information of the 10ms voice-like modulation with the control information of the 10ms voice-like modulation. Figure 7 The 10 ms synchronization signal shown constitutes a 20 ms preamble symbol, wherein the synchronization signal is composed of four 2.5 ms sine wave signals, and the corresponding frequencies are 500 Hz, 1000 Hz, 1500 Hz and 2000 Hz respectively.

[0121] Figure 8 400ms is a schematic diagram of the structure of the voice signal frame provided by the present invention. Figure 8 As shown, 3 blank symbols of 60ms in length, a leading symbol of 20ms and 16 voice data symbols of 320ms form a voice-like signal frame of 400ms in length, which is then transmitted and cyclically sent through the communication channel in segments, wherein the blank symbol is a 20ms all-zero signal.

[0122] The present invention performs differential phase modulation similar to the first encrypted voice signal on the first control information required for key synchronization of the first user terminal, and combines the first synchronization signal of the first user terminal with the first time domain control signal obtained after differential phase modulation and time domain conversion to form a first leading symbol, and then combines the first blank symbol, the first leading symbol and the first type of voice data symbol to form a complete voice-like signal frame which is transmitted to the second user terminal through a voice channel. This not only facilitates the subsequent decryption of the received voice-like signal by the second user terminal, but also ensures the continuity of the signal.

[0123] Optionally, controlling the second user terminal to perform differential phase demodulation on the first type of voice data symbols based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data includes:

[0124] Control the second user terminal to perform frame synchronization on the first type of voice signal frame based on the first blank symbol and the first leading symbol in the received first type of voice signal frame, determine a first starting position of the first leading symbol, and determine a first type of voice data symbol in the first type of voice signal frame based on the first starting position;

[0125] Control the second user terminal to perform differential phase demodulation on the first type of voice data symbols based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data.

[0126] Specifically, when it is determined that the second user terminal has received the first type of voice signal frame sent by the first user terminal, the second user terminal can be controlled to perform frame synchronization on the first type of voice signal frame based on the first blank symbol and the first leading symbol in the received first type of voice signal frame, thereby determining the first starting position of the first leading symbol, and determining the first type of voice data symbol in the first type of voice signal frame based on the first starting position; and then the second user terminal is controlled to perform differential phase demodulation on the first type of voice data symbol based on the first demodulation frequency point and the first demodulation order, thereby obtaining first demodulated voice data.

[0127] Optionally, an energy detection method can be used to detect the energy mutation from the first blank symbol to the first leading symbol, and the approximate position of the first leading symbol can be found through coarse synchronization. Then, fine synchronization can be performed based on the shift cross-correlation method using the synchronization signal locally stored in the second user terminal to further determine the first starting position of the first leading symbol.

[0128] Optionally, Fig. 9 Schematic diagram of the synchronization process of the voice-like signal frame provided by the present invention, such as Fig. 9 As shown, the frame synchronization of the speech-like signal frame can be completed through two stages: coarse synchronization and fine synchronization.

[0129] Optionally, when performing frame synchronization on the first type of speech signal frame, an energy detection algorithm may be used to perform coarse synchronization based on the energy difference between the first blank symbol and the first leading symbol.

[0130] Fig.10 is a schematic diagram of a rough synchronization result based on energy detection provided by the present invention, such as Fig.10 As shown, for example, at an 8KHz sampling rate, 160 points in the first type of speech signal frame are taken according to a single symbol length of 20ms, and the energy ratio of the last 80 points to the first 80 points is calculated. If the ratio is greater than a threshold value of 5, it is considered that the 160 points have the first starting position of the first leading symbol, otherwise move forward 40 points and continue the coarse synchronization operation.

[0131] Optionally, after the coarse synchronization is completed, the fine synchronization operation can be started according to the data segment where the rough starting position of the first leading symbol found by the coarse synchronization is located. The algorithm used is to calculate the cross-correlation coefficient between the 10ms synchronization signal and 80 points starting from the coarse starting position, slide forward 1 sampling point each time to calculate the cross-correlation coefficient, slide 120 points in total, and find the position where the maximum cross-correlation coefficient is located. Fig.11 is a schematic diagram of a detailed synchronization result based on cross-correlation provided by the present invention, such as Fig.11 As shown, if the maximum cross-correlation coefficient is greater than the threshold value 0.8, the fine synchronization is successful, and the first starting position of the first preamble symbol is accurately found, otherwise the coarse synchronization is restarted.

[0132] It can be understood that in an embodiment of the present invention, in order to ensure that the voice data sent by the first user terminal can be restored at the second user terminal, the second user terminal is controlled to perform differential phase demodulation on the first type of voice data symbols based on the first demodulation frequency point, wherein the first demodulation frequency point is the same as the first modulation frequency point, that is, the frequency point used by the second user terminal to demodulate the voice data is the frequency point used by the first user terminal to modulate the voice data, thereby ensuring that the voice data demodulated by the second user terminal is the same as the original voice data to be sent by the first user terminal.

[0133] Optionally, after determining the first starting position of the first leading symbol, the method further includes:

[0134] Controlling the second user terminal to determine a first time domain control signal in the first type of voice signal frame based on the first starting position;

[0135] Control the second user terminal to perform differential phase demodulation on the first time domain control signal based on the first demodulation frequency point and the second demodulation order to obtain first control information, and decrypt and compress and decode the first demodulated voice data based on the first control information to obtain first original voice data.

[0136] Specifically, after determining the first starting position of the first leading symbol, the second user terminal can be controlled to determine the first time domain control signal in the first type of voice signal frame based on the first starting position, and the second user terminal can be further controlled to perform differential phase demodulation on the first time domain control signal based on the first demodulation frequency point and the second demodulation order to obtain first control information, and decrypt and compress and decode the first demodulated voice data based on the first control information to obtain first original voice data, which is the original voice data sent by the first user terminal restored at the second user terminal.

[0137] Optionally, the first demodulated voice data may be decrypted based on a ZUC-256 stream decryption algorithm, and the decrypted voice data may be further compressed and decoded based on a Codec2 decoding algorithm, thereby obtaining the first original voice data.

[0138] It can be understood that in an embodiment of the present invention, in order to ensure that the first control information required for key synchronization can be restored at the second user terminal, the second user terminal is controlled to perform differential phase demodulation on the first time domain control signal based on the first demodulation frequency point, wherein the first demodulation frequency point is the same as the first modulation frequency point, that is, the frequency point used by the second user terminal to demodulate the control information is the frequency point used by the first user terminal to modulate the control information, thereby ensuring that the control information demodulated by the second user terminal is the same as the original control information to be sent by the first user terminal.

[0139] Optionally, transmitting the second-category voice data symbol to the first user terminal includes:

[0140] Control the second user terminal to perform differential phase modulation on the second control information required for key synchronization based on the second modulation frequency and the second modulation order, and perform time domain conversion on the second frequency domain control signal obtained after modulation to obtain a second time domain control signal;

[0141] Combining the second synchronization signal of the second user terminal and the second time domain control signal into a second preamble symbol;

[0142] The second blank symbol, the second leading symbol and the second type of voice data symbol form a second type of voice signal frame;

[0143] Control the second user terminal to transmit the second type of voice signal frame to the first user terminal.

[0144] It can be understood that in order to facilitate the transmission of the encrypted voice signal to the communication counterpart, the encrypted voice signal can be decrypted at the communication counterpart. Therefore, in an embodiment of the present invention, when the second user terminal transmits the second type of voice data symbols to the first user terminal, the second user terminal will also transmit the second control information required for key synchronization to the first user terminal, and in order to ensure the continuity of the signal, a second blank symbol is added to the transmitted second type of voice signal frame.

[0145] Specifically, the second user terminal can be first controlled to perform differential phase modulation on the second control information required for key synchronization based on the second modulation frequency and the second modulation order, and perform time domain conversion on the second frequency domain control signal obtained after modulation to obtain a second time domain control signal; then the second synchronization signal and the second time domain control signal of the second user terminal are combined into a second leading symbol; further, the second blank symbol, the second leading symbol and the second type of voice data symbol are combined into a second type of voice signal frame; finally, the second user terminal is controlled to transmit the second type of voice signal frame to the first user terminal.

[0146] It can be understood that the second control information required for key synchronization is allocated to the second user terminal by a dedicated key distribution center, and the second control information required for key synchronization is used by the first user terminal to decrypt the encrypted voice signal sent by the second user terminal.

[0147] It can be understood that in the embodiment of the present invention, in order to ensure that the clocks of the sender (the second user terminal) and the receiver (the first user terminal) are unified, and the transmission of characters is synchronous and without intervals, the second user terminal is controlled to generate a second synchronization signal, and the second user terminal is controlled to transmit the second synchronization signal together with the voice-like data to be transmitted to the first user terminal. The second synchronization signal is used to notify the first user terminal that a data frame has arrived, and ensure that the sampling speed of the first user terminal and the arrival speed of the bits are consistent, so that the second user terminal and the first user terminal are both synchronized.

[0148] Optionally, in an embodiment of the present invention, in order to ensure signal continuity, a second blank symbol is added to the second type of voice signal frame sent by the second user terminal, wherein the length of the second blank symbol can be determined based on the actually transmitted second type of voice signal frame.

[0149] Optionally, the second blank symbol added to the second type of speech signal frame may be an all-zero signal.

[0150] It can be understood that, in the embodiment of the present invention, by adding a second blank symbol in the second type of voice signal frame sent by the second user terminal, continuous transmission of the second type of voice signal in the voice communication channel can be ensured.

[0151] Optionally, in an embodiment of the present invention, the second user terminal can be controlled to perform differential phase modulation on the second control information required for key synchronization based on a second modulation frequency and a second modulation order, wherein the second modulation order can be the same as the first modulation order or different from the first modulation order, and the embodiment of the present invention does not specifically limit the size of the second modulation order.

[0152] For example, the second user terminal performs 2 in the frequency domain on the second control information required for key synchronization. p The modulated frequency domain signal is then converted into the time domain to obtain a second time domain control signal, and the second synchronization signal of the second user terminal and the second time domain control signal are further combined into a second leading symbol.

[0153] Optionally, the second user terminal may perform similar voice-like modulation on the second control information required for key synchronization according to the method of modulating the second encrypted voice signal.

[0154] Optionally, in an embodiment of the present invention, in order to reduce the bit error rate and ensure the correct transmission of control information, the modulation order p of the second control information required for key synchronization can be less than or equal to the modulation order k of the second encrypted voice signal, that is, the second modulation order is less than or equal to the first modulation order.

[0155] Optionally, after completing the frequency domain differential phase modulation of the second control information, the second user terminal can convert the modulated second frequency domain control signal to the time domain through an inverse fast Fourier transform to obtain a second time domain control signal of voice-like modulation, and then combine the second synchronization signal of the second user terminal and the second time domain control signal into a second leading symbol.

[0156] The present invention performs differential phase modulation similar to the second encrypted voice signal on the second control information required for the key synchronization of the second user terminal, and combines the second synchronization signal of the second user terminal with the second time domain control signal obtained after differential phase modulation and time domain conversion to form a second leading symbol, and then combines the second blank symbol, the second leading symbol and the second type of voice data symbol to form a complete voice-like signal frame which is transmitted to the first user terminal through a voice channel. This not only facilitates the subsequent decryption of the received voice-like signal by the first user terminal, but also ensures the continuity of the signal.

[0157] Optionally, controlling the first user terminal to perform differential phase demodulation on the second-category voice data symbol based on a second demodulation frequency point and a first demodulation order to obtain second demodulated voice data includes:

[0158] Control the first user terminal to perform frame synchronization on the second-class voice signal frame based on the second blank symbol and the second leading symbol in the received second-class voice signal frame, determine the second starting position of the second leading symbol, and determine the second-class voice data symbol in the second-class voice signal frame based on the second starting position;

[0159] Control the first user terminal to perform differential phase demodulation on the second type of voice data symbols based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data.

[0160] Specifically, when it is determined that the first user terminal has received a second type of voice signal frame sent by the second user terminal, the first user terminal can be controlled to perform frame synchronization on the second type of voice signal frame based on the second blank symbol and the second leading symbol in the received second type of voice signal frame, thereby determining the second starting position of the second leading symbol, and determining the second type of voice data symbol in the second type of voice signal frame based on the second starting position; and then the first user terminal is controlled to perform differential phase demodulation on the second type of voice data symbol based on the second demodulation frequency point and the first demodulation order, thereby obtaining second demodulated voice data.

[0161] It can be understood that in an embodiment of the present invention, in order to ensure that the first user terminal can restore the voice data sent by the second user terminal, the first user terminal is controlled to perform differential phase demodulation on the second type of voice data symbols based on the second demodulation frequency point, wherein the second demodulation frequency point is the same as the second modulation frequency point, that is, the frequency point used by the first user terminal to demodulate the voice data is the frequency point used by the second user terminal to modulate the voice data, thereby ensuring that the voice data demodulated by the first user terminal is the same as the original voice data to be sent by the second user terminal.

[0162] Optionally, an energy detection method can be used to detect the energy mutation from the second blank symbol to the second leading symbol, and the approximate position of the second leading symbol can be found through coarse synchronization. Then, fine synchronization can be performed based on the shift cross-correlation method using the synchronization signal locally stored in the first user terminal to further determine the second starting position of the second leading symbol.

[0163] Optionally, after determining the second starting position of the second leading symbol, the method further includes:

[0164] Controlling the first user terminal to determine a second time domain control signal in the second type of voice signal frame based on the second starting position;

[0165] Control the first user terminal to perform differential phase demodulation on the second time domain control signal based on the second demodulation frequency point and the second demodulation order to obtain second control information, and decrypt and compress and decode the second demodulated voice data based on the second control information to obtain second original voice data.

[0166] Specifically, after determining the second starting position of the second leading symbol, the first user terminal can be controlled to determine the second time domain control signal in the second type of voice signal frame based on the second starting position, and the first user terminal can be further controlled to perform differential phase demodulation on the second time domain control signal based on the second demodulation frequency point and the second demodulation order to obtain second control information, and the second demodulated voice data is decrypted and compressed and decoded based on the second control information to obtain second original voice data, which is the original voice data sent by the second user terminal restored at the first user terminal.

[0167] Optionally, the second demodulated voice data may be decrypted based on a ZUC-256 stream decryption algorithm, and the decrypted voice data may be further compressed and decoded based on a Codec2 decoding algorithm, thereby obtaining the second original voice data.

[0168] It can be understood that in an embodiment of the present invention, in order to ensure that the second control information required for key synchronization can be restored at the first user terminal, the first user terminal is controlled to perform differential phase demodulation on the second time domain control signal based on the second demodulation frequency point, wherein the second demodulation frequency point is the same as the second modulation frequency point, that is, the frequency point used by the first user terminal to demodulate the control information is the frequency point used by the second user terminal to modulate the control information, thereby ensuring that the control information demodulated by the first user terminal is the same as the original control information to be sent by the second user terminal.

[0169] For example, the first user terminal and the second user terminal respectively convert the first key synchronization control signal and the second key synchronization control signal into the frequency domain through Fourier transform. p The first user terminal selects the initial frequency point f b =f a +Δf, the initial frequency point selected by the second user terminal is f a , the fundamental frequency is Δf, that is, the frequency used by the first user terminal for demodulation is the frequency used by the second user terminal for modulation: f a +(i×2+1)×Δf(0≤i≤N f ), the frequency point used for demodulation by the second user terminal is the frequency point used by the first user terminal for modulation: f a +i×2×Δf(0≤i≤N f ), the first user terminal and the second user terminal perform 2 p The first demodulation synchronization control signal and the second demodulation synchronization control signal are obtained by performing phase differential phase demodulation.

[0170] For example, according to Figure 6 The differential phase demodulation process shown performs Fourier transform on the time domain control signal (10ms, 160 sampling points) in the leading symbol to convert it to the frequency domain, and then performs second-order differential phase demodulation. During demodulation, the first user terminal demodulates according to the modulation parameters of the second user terminal, and the second user terminal demodulates according to the modulation parameters of the first user terminal, that is, the demodulation initial frequency selected by the first user terminal is 400Hz, and the demodulation initial frequency selected by the second user terminal is 300Hz. The first user terminal calculates the differential phase of every two adjacent frequency points with an interval of 200Hz on the 400+200×i (0≤i≤15) frequency points, and the second user terminal calculates the differential phase of every two adjacent frequency points with an interval of 200Hz on the 300+200×i (0≤i≤15) frequency points. The mapping relationship between the differential phase of adjacent frequency points and the 1-bit data obtained by demodulation is shown in Table 4:

[0171] Table 4 Mapping relationship between differential phase of adjacent frequency points and 1-bit DBPSK demodulation data

[0172]

[0173] In the embodiment of the present invention, 15-bit CRC-encoded control information is obtained after second-order differential phase demodulation, and then CRC decoding is performed on it to obtain 10-bit control information required for key synchronization, which includes a 2-bit key number and an 8-bit frame number. Further based on the 10-bit control information, the demodulated 960-bit encrypted voice data (first demodulated voice data or second demodulated voice data) is decrypted using the ZUC-256 stream decryption algorithm to obtain 960-bit compressed voice data. Then, the Codec2 decoding algorithm is used to decode the 48-bit data in turn to obtain 160-bit (20ms) original voice data. The 960-bit compressed voice data corresponds to 3200 bits (400ms) original voice data, which is the same as Figure 8 The length of a complete voice-like signal frame is the same as that of the original frame, and it can be transmitted to the speaker through the USB sound card for playback. After actual environment testing, the end-to-end delay is less than 100ms, the bit error rate is less than 0.5%, and the voice quality MOS value is greater than 3.6.

[0174] Fig.12 FIG. 1 is a schematic diagram of the working process of the full-duplex voice system provided by the present invention. Fig.12 As shown, the working process of the system includes: first, the sound card of the first user terminal collects voice data, then performs voice activity detection on the collected voice data, and when it is determined that the collected voice data is valid voice data, the valid voice data is further processed, including compression encoding and encryption processing of the valid voice data to obtain the encrypted voice data, further differential phase modulation of the encrypted voice data to obtain voice-like data symbols, and then the blank symbol, the leading symbol and the voice-like data symbol are combined into a complete voice-like signal frame and transmitted to the second user terminal in the voice channel; when the second user terminal receives the voice-like signal frame, frame synchronization and key synchronization are first performed, and then differential phase demodulation is further performed on the voice-like signal frame, and then the voice data obtained after demodulation is decrypted and compressed and decoded, so as to obtain the original voice data collected by the first user terminal, and finally the original voice data is output through the sound card of the second user terminal.

[0175] Optionally, the first user terminal and the second user terminal first perform voice activity detection on the signals collected by their respective sound cards, and compress, encode and encrypt the detected valid voice data; perform frequency domain differential phase modulation on the encrypted voice and convert it to the time domain to obtain a voice-like signal. During differential phase modulation, the communicating parties select different initial frequency points and the same frequency point interval to stagger the frequencies; perform frequency domain differential phase modulation on the control information required for key synchronization and convert it to the time domain to form a leading symbol together with the synchronization signal; form a complete voice-like signal frame with a blank symbol, a leading symbol and n data symbols (voice-like signal) and transmit it in sequence through a voice channel; at the demodulation end (communication counterpart), the received voice-like signal is subjected to frame synchronization, key synchronization, voice-like differential phase demodulation, decryption and compression decoding to obtain the original voice signal.

[0176] The voice-like modulation and demodulation method provided by the present invention controls the first user terminal and the second user terminal to perform differential phase modulation on the encrypted voice signal based on different modulation frequencies, thereby generating a voice-like signal with time-frequency characteristics, and controls the first user terminal and the second user terminal to transmit the voice-like signals generated by each terminal to the communication counterpart and then perform differential phase demodulation. This method can not only effectively avoid the influence of hardware deviation of the communication terminal and voice enhancement processing, but also realize full-duplex voice communication based on this frequency-interleaved modulation and demodulation method.

[0177] The following is a description of the voice-like modulation and demodulation device provided by the present invention. The voice-like modulation and demodulation device described below and the voice-like modulation and demodulation method described above can be referred to each other.

[0178] Fig.13 Schematic diagram of the structure of the voice-like modulation and demodulation device provided by the present invention, such as Fig.13 As shown, the device includes: a determination module 1310, a first control module 1320, a second control module 1330, a third control module 1340 and a fourth control module 1350; wherein:

[0179] The determination module 1310 is used to determine a first encrypted voice signal to be sent by a first user terminal and a second encrypted voice signal to be sent by a second user terminal;

[0180] The first control module 1320 is used to control the first user terminal to perform differential phase modulation on the first encrypted voice signal based on the first modulation frequency and the first modulation order, obtain a first frequency domain voice signal, perform time domain conversion on the first frequency domain voice signal, obtain a first type of voice data symbol, and transmit the first type of voice data symbol to the second user terminal;

[0181] The second control module 1330 is used to control the second user terminal to perform differential phase modulation on the second encrypted voice signal based on the second modulation frequency and the first modulation order, obtain a second frequency domain voice signal, perform time domain conversion on the second frequency domain voice signal, obtain a second type of voice data symbol, and transmit the second type of voice data symbol to the first user terminal;

[0182] The third control module 1340 is used to control the second user terminal to perform differential phase demodulation on the first type of voice data symbol based on the first demodulation frequency point and the first demodulation order to obtain first demodulated voice data when it is determined that the second user terminal receives the first type of voice data symbol;

[0183] The fourth control module 1350 is used to control the first user terminal to perform differential phase demodulation on the second type of voice data symbols based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data when it is determined that the first user terminal receives the second type of voice data symbols;

[0184] Among them, the first modulation frequency is different from the second modulation frequency, the first modulation frequency is the same as the first demodulation frequency, the second modulation frequency is the same as the second demodulation frequency, and the first modulation order is the same as the first demodulation order.

[0185] The voice-like modulation and demodulation device provided by the present invention controls the first user terminal and the second user terminal to perform differential phase modulation on the encrypted voice signal based on different modulation frequencies, thereby generating a voice-like signal with time-frequency characteristics, and controls the first user terminal and the second user terminal to transmit the voice-like signals generated by each terminal to the communication counterpart and then perform differential phase demodulation. This can not only effectively avoid the influence of hardware deviations of the communication terminal and voice enhancement processing, but also realize full-duplex voice communication based on this frequency-interleaved modulation and demodulation method.

[0186] It should be noted here that the above-mentioned voice-like modulation and decoding device provided in the embodiment of the present invention can implement all the method steps implemented in the above-mentioned voice-like modulation and decoding method embodiment, and can achieve the same technical effect. The parts and beneficial effects that are the same as those in the method embodiment will not be described in detail here.

[0187] Fig.14 is a schematic diagram of the physical structure of the electronic device provided by the present invention, such as Fig.14As shown, the electronic device may include: a processor 1410, a communication interface 1420, a memory 1430 and a communication bus 1440, wherein the processor 1410, the communication interface 1420, and the memory 1430 communicate with each other through the communication bus 1440. The processor 1410 may call the logic instructions in the memory 1430 to execute the voice-like modulation and decoding method provided by the above methods, and the method includes:

[0188] Determine a first encrypted voice signal to be sent by a first user terminal and a second encrypted voice signal to be sent by a second user terminal;

[0189] Control the first user terminal to perform differential phase modulation on the first encrypted voice signal based on a first modulation frequency and a first modulation order, obtain a first frequency domain voice signal, perform time domain conversion on the first frequency domain voice signal, obtain a first type of voice data symbol, and transmit the first type of voice data symbol to the second user terminal;

[0190] Control the second user terminal to perform differential phase modulation on the second encrypted voice signal based on the second modulation frequency and the first modulation order, obtain a second frequency domain voice signal, perform time domain conversion on the second frequency domain voice signal, obtain a second type of voice data symbol, and transmit the second type of voice data symbol to the first user terminal;

[0191] When it is determined that the second user terminal receives the first type of voice data symbol, control the second user terminal to perform differential phase demodulation on the first type of voice data symbol based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data;

[0192] When it is determined that the first user terminal receives the second-category voice data symbol, controlling the first user terminal to perform differential phase demodulation on the second-category voice data symbol based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data;

[0193] Among them, the first modulation frequency is different from the second modulation frequency, the first modulation frequency is the same as the first demodulation frequency, the second modulation frequency is the same as the second demodulation frequency, and the first modulation order is the same as the first demodulation order.

[0194] In addition, the logic instructions in the above-mentioned memory 1430 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0195] On the other hand, the present invention further provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, when the program instructions are executed by a computer, the computer can perform the voice-like modulation and demodulation method provided by the above methods, the method comprising:

[0196] Determine a first encrypted voice signal to be sent by a first user terminal and a second encrypted voice signal to be sent by a second user terminal;

[0197] Control the first user terminal to perform differential phase modulation on the first encrypted voice signal based on a first modulation frequency and a first modulation order, obtain a first frequency domain voice signal, perform time domain conversion on the first frequency domain voice signal, obtain a first type of voice data symbol, and transmit the first type of voice data symbol to the second user terminal;

[0198] Control the second user terminal to perform differential phase modulation on the second encrypted voice signal based on the second modulation frequency and the first modulation order, obtain a second frequency domain voice signal, perform time domain conversion on the second frequency domain voice signal, obtain a second type of voice data symbol, and transmit the second type of voice data symbol to the first user terminal;

[0199] When it is determined that the second user terminal receives the first type of voice data symbol, control the second user terminal to perform differential phase demodulation on the first type of voice data symbol based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data;

[0200] When it is determined that the first user terminal receives the second-category voice data symbol, controlling the first user terminal to perform differential phase demodulation on the second-category voice data symbol based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data;

[0201] Among them, the first modulation frequency is different from the second modulation frequency, the first modulation frequency is the same as the first demodulation frequency, the second modulation frequency is the same as the second demodulation frequency, and the first modulation order is the same as the first demodulation order.

[0202] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to perform the above-mentioned voice-like modulation and demodulation methods, the method comprising:

[0203] Determine a first encrypted voice signal to be sent by a first user terminal and a second encrypted voice signal to be sent by a second user terminal;

[0204] Control the first user terminal to perform differential phase modulation on the first encrypted voice signal based on a first modulation frequency and a first modulation order, obtain a first frequency domain voice signal, perform time domain conversion on the first frequency domain voice signal, obtain a first type of voice data symbol, and transmit the first type of voice data symbol to the second user terminal;

[0205] Control the second user terminal to perform differential phase modulation on the second encrypted voice signal based on the second modulation frequency and the first modulation order, obtain a second frequency domain voice signal, perform time domain conversion on the second frequency domain voice signal, obtain a second type of voice data symbol, and transmit the second type of voice data symbol to the first user terminal;

[0206] When it is determined that the second user terminal receives the first type of voice data symbol, control the second user terminal to perform differential phase demodulation on the first type of voice data symbol based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data;

[0207] When it is determined that the first user terminal receives the second-category voice data symbol, controlling the first user terminal to perform differential phase demodulation on the second-category voice data symbol based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data;

[0208] Among them, the first modulation frequency is different from the second modulation frequency, the first modulation frequency is the same as the first demodulation frequency, the second modulation frequency is the same as the second demodulation frequency, and the first modulation order is the same as the first demodulation order.

[0209] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0210] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0211] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A speech-like modulation and demodulation method, characterized in that: include: Determine a first encrypted voice signal to be sent by a first user terminal and a second encrypted voice signal to be sent by a second user terminal; Control the first user terminal to perform differential phase modulation on the first encrypted voice signal based on a first modulation frequency and a first modulation order, obtain a first frequency domain voice signal, perform time domain conversion on the first frequency domain voice signal, obtain a first type of voice data symbol, and transmit the first type of voice data symbol to the second user terminal; Control the second user terminal to perform differential phase modulation on the second encrypted voice signal based on the second modulation frequency and the first modulation order, obtain a second frequency domain voice signal, perform time domain conversion on the second frequency domain voice signal, obtain a second type of voice data symbol, and transmit the second type of voice data symbol to the first user terminal; When it is determined that the second user terminal receives the first type of voice data symbol, control the second user terminal to perform differential phase demodulation on the first type of voice data symbol based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data; When it is determined that the first user terminal receives the second-category voice data symbol, controlling the first user terminal to perform differential phase demodulation on the second-category voice data symbol based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data; Among them, the first modulation frequency is different from the second modulation frequency, the first modulation frequency is the same as the first demodulation frequency, the second modulation frequency is the same as the second demodulation frequency, and the first modulation order is the same as the first demodulation order.

2. The speech-like modulation and demodulation method according to claim 1, characterized in that: Transmitting the first type of voice data symbols to a second user terminal includes: Control the first user terminal to perform differential phase modulation on the first control information required for key synchronization based on the first modulation frequency and the second modulation order, and perform time domain conversion on the first frequency domain control signal obtained after modulation to obtain a first time domain control signal; Combining the first synchronization signal of the first user terminal and the first time domain control signal into a first preamble symbol; The first blank symbol, the first leading symbol and the first type of voice data symbol form a first type of voice signal frame; Control the first user terminal to transmit the first type of voice signal frame to the second user terminal.

3. The speech-like modulation and demodulation method according to claim 2, characterized in that: Controlling the second user terminal to perform differential phase demodulation on the first type of voice data symbols based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data, including: Control the second user terminal to perform frame synchronization on the first type of voice signal frame based on the first blank symbol and the first leading symbol in the received first type of voice signal frame, determine a first starting position of the first leading symbol, and determine a first type of voice data symbol in the first type of voice signal frame based on the first starting position; Control the second user terminal to perform differential phase demodulation on the first type of voice data symbols based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data.

4. The speech-like modulation and demodulation method according to claim 3, characterized in that: After determining the first starting position of the first leading symbol, the method further includes: Controlling the second user terminal to determine a first time domain control signal in the first type of voice signal frame based on the first starting position; Control the second user terminal to perform differential phase demodulation on the first time domain control signal based on the first demodulation frequency point and the second demodulation order to obtain first control information, and decrypt and compress and decode the first demodulated voice data based on the first control information to obtain first original voice data.

5. The speech-like modulation and demodulation method according to claim 1, characterized in that: Transmitting the second-category voice data symbol to the first user terminal includes: Control the second user terminal to perform differential phase modulation on the second control information required for key synchronization based on the second modulation frequency and the second modulation order, and perform time domain conversion on the second frequency domain control signal obtained after modulation to obtain a second time domain control signal; Combining the second synchronization signal of the second user terminal and the second time domain control signal into a second preamble symbol; The second blank symbol, the second leading symbol and the second type of voice data symbol form a second type of voice signal frame; Control the second user terminal to transmit the second type of voice signal frame to the first user terminal.

6. The speech-like modulation and demodulation method according to claim 5, characterized in that: Controlling the first user terminal to perform differential phase demodulation on the second type of voice data symbols based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data, including: Control the first user terminal to perform frame synchronization on the second-class voice signal frame based on the second blank symbol and the second leading symbol in the received second-class voice signal frame, determine the second starting position of the second leading symbol, and determine the second-class voice data symbol in the second-class voice signal frame based on the second starting position; Control the first user terminal to perform differential phase demodulation on the second type of voice data symbols based on the second demodulation frequency point and the first demodulation order to obtain second demodulated voice data.

7. The speech-like modulation and demodulation method according to claim 6, characterized in that: After determining the second starting position of the second leading symbol, the method further includes: Controlling the first user terminal to determine a second time domain control signal in the second type of voice signal frame based on the second starting position; Control the first user terminal to perform differential phase demodulation on the second time domain control signal based on the second demodulation frequency point and the second demodulation order to obtain second control information, and decrypt and compress and decode the second demodulated voice data based on the second control information to obtain second original voice data.

8. The speech-like modulation and demodulation method according to claim 2, characterized in that: The second modulation order is less than or equal to the first modulation order.

9. A voice-like modem device, characterized in that: include: A determination module, used to determine a first encrypted voice signal to be sent by a first user terminal and a second encrypted voice signal to be sent by a second user terminal; A first control module, used to control the first user terminal to perform differential phase modulation on the first encrypted voice signal based on a first modulation frequency and a first modulation order, obtain a first frequency domain voice signal, perform time domain conversion on the first frequency domain voice signal, obtain a first type of voice data symbol, and transmit the first type of voice data symbol to a second user terminal; A second control module, used to control the second user terminal to perform differential phase modulation on the second encrypted voice signal based on a second modulation frequency and a first modulation order, obtain a second frequency domain voice signal, perform time domain conversion on the second frequency domain voice signal, obtain a second type of voice data symbol, and transmit the second type of voice data symbol to the first user terminal; A third control module is used to control the second user terminal to perform differential phase demodulation on the first type of voice data symbol based on a first demodulation frequency point and a first demodulation order to obtain first demodulated voice data when it is determined that the second user terminal receives the first type of voice data symbol; a fourth control module, configured to control the first user terminal to perform differential phase demodulation on the second type of voice data symbols based on a second demodulation frequency point and a first demodulation order to obtain second demodulated voice data when it is determined that the first user terminal receives the second type of voice data symbols; Among them, the first modulation frequency is different from the second modulation frequency, the first modulation frequency is the same as the first demodulation frequency, the second modulation frequency is the same as the second demodulation frequency, and the first modulation order is the same as the first demodulation order.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the speech-like modulation and demodulation method as claimed in any one of claims 1 to 8 is implemented.

11. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the speech-like modulation and demodulation method according to any one of claims 1 to 8 is implemented.

Images