CN101414850B - Method for generating and receiving multi-system biorthogonal direct sequence frequency hopping mixed signal - Google Patents

Abstract

A method for generating and receiving a multi-level dual orthogonal direct spread frequency hopping mixed signal, which relates to a method for generating and receiving a direct spread frequency hopping mixed signal, in order to solve the problem that the transmission rate of the existing mixed direct spread frequency hopping signal is greatly limited by the bandwidth. At the transmitting end, the information data is serial-to-parallel converted, the generated parallel data is modulated by multi-level dual orthogonal keying, and then the modulated signal is processed by frequency hopping to make it have stronger anti-interference ability and multiple access ability, and then transmitted by the antenna; at the receiving end, the received signal is first de-hopped and demodulated, and then the local dual orthogonal code is correlated with the demodulated received signal, and the transmitted dual orthogonal code is judged by calculating the correlation value and its positive and negative relationship, and then the original data is restored by parallel-to-serial conversion. The present invention can improve the data transmission rate without changing the bandwidth occupied by the system, and can also enable the system to support more users at the same time.

Description

A Generation and Reception Method of Multi-Byrthogonal Direct Spread Frequency Hopping Mixed Signal

technical field

The invention relates to a method for generating and receiving a direct spread frequency hopping mixed signal, which belongs to the field of spread spectrum technology in wireless communication.

Background technique

Because the spread spectrum communication method of hybrid direct spread frequency hopping not only has the ability of direct sequence spread spectrum communication to resist multipath interference, but also has the ability of frequency hopping communication to resist narrowband interference and near-far effect, so it has been more and more popular in recent years. s concern. However, the anti-interference ability of spread spectrum communication is obtained at the cost of expanding the signal bandwidth. In the bandwidth-limited environment, the improvement of the information transmission rate is limited due to the inability to provide a wider bandwidth. How to increase user data transmission rate under certain bandwidth conditions to adapt to the development of high data rate and multimedia services is the goal pursued by people.

Contents of the invention

In order to solve the problem that the transmission rate of the existing mixed direct spread frequency hopping signal is greatly limited by the bandwidth, the invention provides a method for generating and receiving the multi-ary system dual orthogonal direct spread frequency hopping mixed signal. The present invention comprises the following steps:

Launch process:

Step 1. Obtain a symbol by serial-to-parallel conversion of the binary digital information;

Step 2: Map the symbols through the biorthogonal sequence to obtain the biorthogonal sequence C _i generated by the transmitter, where i=-2 ^k-1 , -1, 1, 2 ^k-1 , C _i ∈ (-1, 0,1);

Step 3, generating the frequency hopping signal of the transmitting terminal according to the frequency hopping sequence of the transmitting terminal;

Step 4, after modulating the bi-orthogonal sequence C _i generated by the transmitting end, and then mixing with the hopping frequency signal of the transmitting end to generate a transmitting signal, the transmitting signal is amplified and then transmitted;

Receiving process:

Step 5, performing band-pass filtering on the received signal to obtain the filtered received signal;

Step 6. Generate a frequency hopping signal at the receiving end according to the frequency hopping sequence generated by the receiving end that is consistent with the transmitting end;

Step 7, complete the dehopping of the frequency hopping signal at the receiving end by mixing the frequency hopping signal at the receiving end and the filtered receiving signal;

Step 8: Filter the de-hopped frequency hopping signal of the receiving end, and then obtain the biorthogonal sequence C _i received by the receiving end through demodulation, where i=-2 ^k-1 , -1, 1, 2 ^{k- 1} , C _i ∈ (-1, 0, 1);

Step 9: Correlate the biorthogonal sequence C _j locally generated by the receiving end with the biorthogonal sequence C _i received by the receiving end, where j=1,...,2 ^k-1 , C _j ∈ (0, 1), and judge after each correlation value is integrated respectively, finally will judge the signal that obtains the peak value, and judge according to the polarity of the peak value that the biorthogonal sequence received by the receiving end is Ci or C _{-i ;}

Step 10: Map the determined bi-orthogonal sequence C _i received by the receiving end into symbols, and then obtain binary digital information through parallel-to-serial conversion.

Beneficial effects: the present invention adopts the mixed spread spectrum communication system of multi-ary system bi-orthogonal keying modulation, not only has the ability of direct sequence spread spectrum communication to resist multipath interference, but also has the ability of frequency hopping communication to resist narrowband interference and near-far effect , and by adopting multi-binary bi-orthogonal keying modulation technology, the data transmission rate can be improved without changing the bandwidth occupied by the system; the present invention adds multiple The binary orthogonal keying modulation can increase the data transmission rate of the system without changing the symbol rate of the spreading code, that is, without increasing the system bandwidth; The cross-correlation of different users can make the code groups of different users be well identified and distinguished, and the system can obtain the ability of code division multiple access on the basis of frequency hopping multiple access; the users supported by frequency hopping communication can reach saturation In this case, the system can improve user capacity by allocating different dual-orthogonal code groups for different users, and the use of dual-orthogonal codes can make the number of orthogonal codes required for a single user code group comparable to that of the usual multi-ary orthogonal codes. The ratio is reduced by half, that is, by adopting the bi-orthogonal method, 200% of the users of the original multi-ary communication system can be supported on the basis of the same number of orthogonal codes.

Description of drawings

Figure 1 is a schematic diagram of the transmitter structure of the hybrid direct sequence and frequency hopping spread spectrum signal using multi-ary dual orthogonal keying modulation; Figure 2 is the hybrid direct sequence and frequency hopping spread spectrum signal using multi-ary dual orthogonal keying modulation Schematic diagram of the receiver structure of the frequency signal.

Detailed ways

The specific embodiment: referring to Fig. 1 and Fig. 2, the present embodiment is made up of the following steps:

Launch process:

Step 1, the k-bit binary digital information output by the information source 1 is converted into a symbol by the serial-to-parallel converter 2, wherein k represents a natural number;

Step 2: Map the symbol to the bi-orthogonal sequence C _i generated by the transmitting end through the bio-orthogonal sequence mapper 3 at the transmitting end, where i=-2 ^{k-1 , -1} , 1, 2 ^k-1 , C _i ∈(-1,0,1);

Step 3, according to the frequency hopping sequence produced by the frequency hopping sequence generator 5 at the transmitting end, the frequency synthesizer 4 at the transmitting end generates a frequency hopping signal at the transmitting end;

Step 4: The biorthogonal sequence C _i generated by the transmitter is first modulated by the modulator 6, and then mixed with the transmitter frequency hopping signal by the transmitter mixer 7 to generate a transmit signal, and the transmit signal is amplified by the amplifier 8 by Transmitter antenna transmits;

Receiving process:

Step 5, the band-pass filter 9 performs band-pass filtering on the received signal to obtain the filtered received signal;

Step 6, according to the frequency hopping sequence generated by the frequency hopping sequence generator 11 at the receiving end and the frequency hopping sequence at the transmitting end, the frequency synthesizer at the receiving end 10 generates the frequency hopping signal at the receiving end,

Step 7, mixing the frequency hopping signal at the receiving end and the filtered received signal through the mixer 12 at the receiving end to complete the de-hopping of the frequency hopping signal at the receiving end;

Step 8: Filter the de-hopped frequency hopping signal of the receiving end through the intermediate frequency filter 13, and then demodulate it through the demodulator 14 to obtain the biorthogonal sequence C _i received by the receiving end, where i=-2 ^k-1 , -1, 1, 2 ^k-1 , C _i ∈ (-1, 0, 1);

Step 9: Correlate the biorthogonal sequence C _j locally generated by the biorthogonal code mapper 15 at the receiving end with the biorthogonal sequence C _i received at the receiving end, where j=1,...,2 ^k-1 , C _j ∈ (0, 1), and each correlation value is integrated by the integrator 17 and then judged by the decider 18. Finally, the signal output by the correlator 16 that has obtained the peak value is judged to be received according to the polarity of the peak value. The biorthogonal sequence received by the end is C _i or C _-i ;

Step ten, the symbol determiner 19 maps the bi-orthogonal sequence C _i received by the receiving end into symbols, and converts them through the parallel-to-serial converter 20 to obtain k-bit binary digital information.

The basic idea of this embodiment is to perform serial-to-parallel conversion on the information data at the transmitting end, and perform multi-ary system biorthogonal key modulation on the generated parallel data combination (symbol), so that different symbols correspond to different biorthogonal keying modulations. code, and then the modulated signal is processed by frequency hopping to make it have stronger anti-interference ability and multiple access ability, and then it is transmitted by the antenna; at the receiving end, the received signal is first de-hopped and demodulated, and then the Correlation processing between the bi-orthogonal code and the demodulated received signal, by calculating the correlation value and judging which bi-orthogonal code is transmitted according to the positive or negative of the correlation value, it can be determined which symbol the source data is , and then restore the original data through parallel-to-serial conversion.

Multi-ary bi-orthogonal keying modulation, also known as M-ary bi-orthogonal keying (M-ary Bi-Orthogonal Keying) modulation, uses a spreading sequence to represent multiple bits of information, and can obtain available data at a fixed symbol rate. variable data transfer rate. The specific modulation process is:

The k-bit information is serially converted into a symbol, and a symbol corresponds to a biorthogonal sequence C _i , where i=-2 ^k-1 , -1, 1, 2 ^k-1 , C _i ∈ (-1, 0, 1), k-bit information generates a total of M (M=2 ^k ) symbols, corresponding to M biorthogonal sequences, biorthogonal sequences C _i satisfy the following formula:

$\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; c</span>}}_{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; c</span>}}_{{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}<span\; class="notranslate">\; ,</span>& {\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; ,</span>& <span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; \&NotEqual;</span><span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; i</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; |</span>\end{array}\right.$

Where e is the number of non-zero elements in C _i , and L is the number of elements in C _i .

At the receiving end, only half of the original number of biorthogonal sequences can be used to achieve despreading, that is, the biorthogonal sequence is used to correlate with the received signal, first determine which correlator has obtained the peak value, and judge the receiving signal according to the polarity of the peak value. Significance of terminal biorthogonal sequences.

The serial-to-parallel conversion of the information data stream is performed in a 1:4 manner, that is, each symbol is composed of 4-bit data, and there are 2 ⁴ =16 combinations of 4-bit data. The bi-orthogonal code can be modified walsh code, choose 8 codes as the local bi-orthogonal codes, numbered as C ₁ to C ₈ , and invert these 8 codes to get C _-1 to C _-8 , then the numbers are The 16 codes of C ₁ to C ₈ and C _-1 to C _-8 constitute the required bi-orthogonal code group, corresponding to 16 symbols generated by 4-bit data. Because of the orthogonality among Walsh codes, different users can make the system obtain multiple addresses by selecting different Walsh code groups.

According to the preset code group correspondence, the current information symbol is mapped into a corresponding bi-orthogonal sequence, assuming that the mapping is C ₂ , and the modulator will modulate C ₂ onto the carrier according to the required modulation method (eg, BPSK). Frequency hopping is then performed on the signal output by the modulator. The frequency hopping sequence generator generates a pseudo-random code (such as m-sequence), and the pseudo-random code discretely controls the output frequency of the frequency synthesizer, so that the frequency of the transmitted signal hops with the change of the pseudo-random code. The signal output by the modulator is mixed with the hopping frequency signal output by the frequency synthesizer, so that the frequency of the output signal of the mixer hops with the instantaneous value of the pseudo-random code, and the frequency hopping function is realized. Different pseudo-random codes can make the instantaneous frequency of the frequency synthesizer hop in different orders, that is, hop according to different frequency hopping patterns. Different users use different frequency hopping patterns to make the frequency hopping system have multiple access capabilities.

The signal processed by frequency hopping is amplified by the amplifier and sent out by the antenna. At the receiving end, the received signal first filters out-of-band noise through a band-pass filter, and then performs de-hopping processing. The frequency hopping sequence generator at the receiving end generates the same pseudo-random sequence as the transmitting end, then the frequency synthesizer can output a frequency signal consistent with the hopping sequence of the transmitting end, and mix this signal with the receiving signal to obtain Receive the signal for de-hopping. The de-hopped signal is demodulated after being passed through an intermediate frequency filter, and the demodulator will output a bi-orthogonal code C ₂ .

Then the bi-orthogonal code C ₂ is correlated with the 8 bi-orthogonal codes C ₁ to C ₈ locally stored at the receiving end through 8 correlators, and the correlation results are integrated through the integrator. Due to the orthogonality between bi-orthogonal codes, only the correlator and integrator corresponding to C ₂ have peak output, and the output of other integrators is zero. According to the peak output of the integrator corresponding to C ₂ , the decision device judges that the biorthogonal sequence sent is C ₂ or C _-2 , and then judges that it is C ₂ according to the output peak polarity is positive, if the peak polarity is negative, Then it is judged as C _-2 . Subsequently, the symbol decision unit judges the information symbols according to the correspondence relationship between the preset bi-orthogonal sequence and the information symbols, and the information symbols are converted to parallel to serial to restore the original 4-bit data.

Claims (1)

1. the generation of a multi-scale dual-quadrature straight-extend frequency-hopping mixing signal and method of reseptance is characterized in that it may further comprise the steps:

Emission process:

Step 1, binary digital information is obtained a code element through string and conversion;

Step 2, code element is obtained the many bi-orthogonal sequences C that transmitting terminal produces through many bi-orthogonal sequences mapping _i, i=-2 wherein ^K-1,-1,1,2 ^K-1, wherein k representes natural number, C _i∈ (1,0,1);

Step 3, produce transmitting terminal jump frequency signal according to the transmitting terminal frequency hop sequences;

Step 4, the many bi-orthogonal sequences C that transmitting terminal is produced _iAfter modulation, produce with transmitting terminal jump frequency signal mixing again and transmit emission after process is amplified;

Receiving course:

Step 5, will receive signal and carry out bandpass filtering and obtain filtering and receive signal;

Step 6, the frequency hop sequences consistent that produces according to receiving terminal with transmitting terminal, generation receiving terminal jump frequency signal;

Step 7, receiving terminal jump frequency signal and filtering are received signal accomplish the jumping of separating receiving terminal jump frequency signal through mixing;

Step 8, the receiving terminal jump frequency signal that will separate jumping carry out filtering, obtain the many bi-orthogonal sequences C that receiving terminal receives through demodulation again _i, i=-2 wherein ^K-1,-1,1,2 ^K-1, C _i∈ (1,0,1);

Step 9, with the local many bi-orthogonal sequences C that produces of receiving terminal _jThe many bi-orthogonal sequences C that receives with receiving terminal respectively _iRelevant, j=1 wherein ..., 2 ^K-1, C _j∈ (0,1), and each correlation adjudicated behind the integration respectively will rule out the signal that obtains peak value at last, and judge the positive negativity of the many bi-orthogonal sequences that receiving terminal receives according to the polarity of peak value;

Step 10, the many bi-orthogonal sequences C that the receiving terminal that rules out is received _iBe mapped to code element, pass through again and string conversion acquisition binary digital information.

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