阅读说明：本技术 基于fh-ofdm的导航通信一体化信号波形构造方法及系统 (Navigation communication integrated signal waveform construction method and system based on FH-OFDM ) 是由 史文娟 郇存宏 王芸 谢旭峰 王紫涵 于 2020-12-25 设计创作，主要内容包括：本发明提供了一种基于FH-OFDM的导航通信一体化信号波形构造方法及系统,包括：步骤S1：构造导通一体化OFDM多载波信号；步骤S2：构造子载波跳频OFDM信号；步骤S3：构造基于OFDM+CAZAC序列的测量信号；步骤S4：根据导通一体化OFDM多载波信号、子载波跳频OFDM信号、基于OFDM+CAZAC序列的测量信号,获取基于FH-OFDM的导航通信一体化信号波形构造结果信息。本发明实现了电台高速导通一体化,同时使电台在恶劣信道环境下仍然具有很强的抗截获、抗破译和抗干扰能力。(The invention provides a navigation communication integrated signal waveform construction method and a system based on FH-OFDM, comprising the following steps: step S1: constructing and conducting an integrated OFDM multi-carrier signal; step S2: constructing a subcarrier frequency hopping OFDM signal; step S3: constructing a measurement signal based on an OFDM + CAZAC sequence; step S4: and acquiring information of the waveform construction result of the navigation communication integrated signal based on FH-OFDM according to the conduction integrated OFDM multi-carrier signal, the sub-carrier frequency hopping OFDM signal and the measurement signal based on the OFDM + CAZAC sequence. The invention realizes the high-speed conduction integration of the radio station, and simultaneously ensures that the radio station still has strong anti-interception, anti-decoding and anti-interference capabilities under the severe channel environment.)

1. A navigation communication integrated signal waveform construction method based on FH-OFDM is characterized by comprising the following steps:

step S1: constructing control information according to the conduction integrated OFDM multi-carrier signal, and constructing the conduction integrated OFDM multi-carrier signal;

step S2: constructing control information according to the subcarrier frequency hopping OFDM signal, and constructing a subcarrier frequency hopping OFDM signal;

step S3: control information is constructed according to the measurement signals based on the OFDM + CAZAC sequence, and the measurement signals based on the OFDM + CAZAC sequence are constructed;

step S4: and acquiring information of the waveform construction result of the navigation communication integrated signal based on FH-OFDM according to the conduction integrated OFDM multi-carrier signal, the sub-carrier frequency hopping OFDM signal and the measurement signal based on the OFDM + CAZAC sequence.

2. The FH-OFDM-based navigation communication integration signal waveform construction method of claim 1, wherein said step S1 includes:

step S1.1: OFDM divides the overall signal bandwidth into multiple sub-channels, and adjusts the construction of the different sub-channels to transmit the signal.

3. The FH-OFDM-based navigation communication integration signal waveform construction method of claim 1, wherein said step S2 includes:

step S2.1: and selecting a subcarrier frequency hopping OFDM structure in the mode of combining the frequency hopping and the OFDM system.

4. The FH-OFDM-based navigation communication integration signal waveform construction method of claim 3, wherein said step S2 includes:

step S2.2: and generating a frequency modulation map of system frequency hopping through the chaotic sequence, and then completing the mapping process of the sub-carrier in the modulation process of the baseband OFDM.

5. The FH-OFDM-based navigation communication integration signal waveform construction method of claim 1, wherein said step S3 includes:

step S3.1: in the aspect of measuring signal construction, the ranging and clock error measurement based on a spread spectrum measurement channel is realized by utilizing the time-frequency characteristics of OFDM and combining the perfect autocorrelation and cross-correlation characteristics of a CAZAC sequence.

6. A FH-OFDM based navigation communication integrated signal waveform construction system is characterized by comprising:

module M1: constructing control information according to the conduction integrated OFDM multi-carrier signal, and constructing the conduction integrated OFDM multi-carrier signal;

module M2: constructing control information according to the subcarrier frequency hopping OFDM signal, and constructing a subcarrier frequency hopping OFDM signal;

module M3: control information is constructed according to the measurement signals based on the OFDM + CAZAC sequence, and the measurement signals based on the OFDM + CAZAC sequence are constructed;

module M4: and acquiring information of the waveform construction result of the navigation communication integrated signal based on FH-OFDM according to the conduction integrated OFDM multi-carrier signal, the sub-carrier frequency hopping OFDM signal and the measurement signal based on the OFDM + CAZAC sequence.

7. The FH-OFDM-based navigational communication integration signal waveform construction system of claim 6, wherein said module M1 includes:

module M1.1: OFDM divides the overall signal bandwidth into multiple sub-channels, and adjusts the construction of the different sub-channels to transmit the signal.

8. The FH-OFDM-based navigational communication integration signal waveform construction system of claim 6, wherein said module M2 includes:

module M2.1: and selecting a subcarrier frequency hopping OFDM structure in the mode of combining the frequency hopping and the OFDM system.

9. The FH-OFDM-based navigational communication integration signal waveform construction system of claim 8, wherein said module M2 includes:

module M2.2: and generating a frequency modulation map of system frequency hopping through the chaotic sequence, and then completing the mapping process of the sub-carrier in the modulation process of the baseband OFDM.

10. The FH-OFDM-based navigational communication integration signal waveform construction system of claim 6, wherein said module M3 includes:

module M3.1: in the aspect of measuring signal construction, the ranging and clock error measurement based on a spread spectrum measurement channel is realized by utilizing the time-frequency characteristics of OFDM and combining the perfect autocorrelation and cross-correlation characteristics of a CAZAC sequence.

Technical Field

The invention relates to the technical field of FH-OFDM navigation communication, in particular to a FH-OFDM navigation communication integrated signal waveform construction method and a FH-OFDM navigation communication integrated signal waveform construction system.

Background

The navigation positioning technology plays an increasingly important role in modern war, the satellite navigation signal is easy to interfere and other vulnerability problems are gradually shown, and the high-strength combat requirements in the future are difficult to meet. The communication network taking the radio station as the user equipment has the end-to-end communication capability, so that a closer signal link is provided in the process of receiving and transmitting signals relative to ground-based radio navigation and satellite navigation, the wireless communication signals have higher receiving power in practical application, and meanwhile, a series of anti-interference and anti-cheating measures such as frequency hopping, encryption and the like are fused in the communication network, so that the communication network has outstanding anti-interference advantages relative to other navigation modes.

Aiming at the requirements of high-speed conduction integration, high-speed data transmission, anti-interference and anti-interception of military radio stations, a radio station waveform structure based on FH-OFDM is provided. The waveform structure can be adaptively adjusted according to the transmission requirements of narrow-band and wide-band, so that the requirement of multi-waveform structure is met; by adopting a structure based on subcarrier frequency hopping, strong anti-interference and anti-interception based on broadband frequency hopping can be realized; the spread spectrum measurement signal constructed based on the CAZAC sequence has excellent correlation characteristics, and the high-precision time service and distance measurement functions can be realized by adopting a bidirectional measurement system.

Patent document CN1658699A discloses a handoff method in a mobile communication system using frequency hopping-orthogonal frequency division multiplexing (FH-OFDM). The mobile host predicts the handoff according to the sending power intensity of the current service base station; reserving a physical channel required for a handoff with respect to at least one candidate base station; selecting a handoff target base station from at least one candidate base station; releasing a channel connected with a serving base station; and carrying out data communication with the target base station through the reserved physical channel. The patent document still leaves room for improvement in process configuration and technical performance.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a navigation communication integrated signal waveform construction method and system based on FH-OFDM.

The invention provides a navigation communication integrated signal waveform construction method based on FH-OFDM, which comprises the following steps:

step S1: constructing control information according to the conduction integrated OFDM multi-carrier signal, and constructing the conduction integrated OFDM multi-carrier signal; step S2: constructing control information according to the subcarrier frequency hopping OFDM signal, and constructing a subcarrier frequency hopping OFDM signal; step S3: control information is constructed according to the measurement signals based on the OFDM + CAZAC sequence, and the measurement signals based on the OFDM + CAZAC sequence are constructed; step S4: and acquiring information of the waveform construction result of the navigation communication integrated signal based on FH-OFDM according to the conduction integrated OFDM multi-carrier signal, the sub-carrier frequency hopping OFDM signal and the measurement signal based on the OFDM + CAZAC sequence.

Preferably, the step S1 includes: step S1.1: OFDM divides the whole signal bandwidth into a plurality of sub-channels, and transmits the signal structure by adjusting different sub-channels; different service functions such as measurement and communication can be met, and dynamic adjustment of link resources is realized.

When communication is carried out among the radio stations, all the sub-channels are communication channels;

when the radio station needs to carry out inter-station ranging or time synchronization with other radio stations, a sub-channel is divided into measuring channels, and pseudo code modulation measuring signals are transmitted to realize inter-station measurement.

Preferably, the step S2 includes:

step S2.1: aiming at the anti-interference requirement of military radio station work, a signal modulation mode of subcarrier frequency hopping OFDM is adopted to realize the anti-interference, anti-interception and multi-waveform compatible construction requirements.

Selecting a subcarrier frequency hopping OFDM structure in a mode of combining frequency hopping and OFDM systems;

preferably, the step S2 includes:

step S2.2: and generating a frequency modulation map of system frequency hopping through the chaotic sequence, and then completing the mapping process of the sub-carrier in the modulation process of the baseband OFDM.

Compared with an OFDM system based on radio frequency hopping, the method has the characteristics of easy digitization, simple realization, easy increase of frequency hopping points, high frequency spectrum utilization rate and strong concealment.

Based on the flexible configuration characteristic of multiple subcarriers of OFDM signals, the method can meet the requirements of narrowband and broadband frequency hopping signal waveform construction. When the waveform is generated, the bandwidth regulating bandwidth interval and the subcarrier channel bandwidth are determined according to the signal bandwidth condition and the requirement, and different signal transmission rate requirements can be adapted by distributing different numbers of subcarriers to users and matching with modulation modes with different orders. Specifically, aiming at the subcarrier FH-OFDM technology of broadband signals, in the frequency hopping process, the frequency points of a plurality of subcarriers are selected in a broadband through the generation of frequency hopping patterns, and the broadband frequency hopping sending process is completed; aiming at the subcarrier FH-OFDM technology of the narrowband signal, the subcarrier to be selected is generated according to a relatively large frequency hopping frequency point range, and the narrowband signal is modulated on the subcarrier of the fixed frequency point to complete broadband frequency hopping, so that the anti-interference purpose is achieved.

For the subcarrier allocation of different radio stations, a subcarrier interleaving aggregation strategy is adopted, namely, different radio station signals are formed by the aggregation of discontinuous subcarriers in a frequency hopping bandwidth range, and meanwhile, a better frequency diversity effect can be further obtained, and the radio station navigation communication has stronger interception resistance and interference resistance.

Preferably, the step S3 includes:

step S3.1: in the aspect of measuring signal construction, the ranging and clock error measurement based on a spread spectrum measurement channel is realized by utilizing the time-frequency characteristics of OFDM and combining the perfect autocorrelation and cross-correlation characteristics of a CAZAC sequence.

CAZAC sequences are known as constant-envelope autocorrelation sequences and have the following characteristics:

1. constant envelope property. The amplitude of any CAZAC sequence is constant, and the characteristic can ensure that each frequency point in corresponding bandwidth experiences the same excitation, thereby facilitating the realization of unbiased estimation in coherent detection.

2. Ideal periodic autocorrelation properties. The name correlation peak is sharp for any CAZAC original sequence and the complementary correlation name correlation peak of the sequence obtained after circularly shifting n bits.

3. Good mutual characteristics. Namely, the cross correlation and partial correlation values are close to zero, so that the receiving end can accurately detect the required signal and reduce detection errors.

4. Low peak-to-average ratio (PAPR/CM). The ratio of the expected mean of the peaks of the time domain signal composed of any CAZAC sequence is low, thereby facilitating the implementation of the power amplifier.

5. The fourier transform is still followed by a CAZAC sequence. Any CAZAC sequence remains a CAZAC sequence after fourier transform/inverse fourier transform (FFT/IFFT), having all the properties of a CAZAC sequence.

Due to the excellent autocorrelation characteristic, the receiving end can extract accurate measurement information from the sequence conveniently, so that the distance information can be calculated accurately; meanwhile, due to the good cross-correlation characteristic, the multi-address capability of the radio station is superior in military radio stations, and the system capacity can be effectively improved; the CAZAC sequence is selected as the sending data, so that the OFDM signal can achieve a smaller peak-to-average ratio, and the problem of high inherent peak-to-average ratio of the OFDM signal can be solved.

The CAZAC sequence selected by the project is a Zadoff-Chu sequence (ZC sequence), and the mathematical expression of the CAZAC sequence is as follows:

wherein N is the sequence length, k is 0,1, …, N-1, j²R is any positive integer coprime to N. The autocorrelation curve of the CAZAC sequence with N839 is as follows, and good autocorrelation performance can be seen from the figure.

The invention provides a navigation communication integrated signal waveform construction system based on FH-OFDM, which comprises:

module M1: constructing control information according to the conduction integrated OFDM multi-carrier signal, and constructing the conduction integrated OFDM multi-carrier signal; module M2: constructing control information according to the subcarrier frequency hopping OFDM signal, and constructing a subcarrier frequency hopping OFDM signal; module M3: control information is constructed according to the measurement signals based on the OFDM + CAZAC sequence, and the measurement signals based on the OFDM + CAZAC sequence are constructed; module M4: and acquiring information of the waveform construction result of the navigation communication integrated signal based on FH-OFDM according to the conduction integrated OFDM multi-carrier signal, the sub-carrier frequency hopping OFDM signal and the measurement signal based on the OFDM + CAZAC sequence.

Preferably, said module M1 comprises: module M1.1: OFDM divides the whole signal bandwidth into a plurality of sub-channels, and transmits the signal structure by adjusting different sub-channels; different service functions such as measurement and communication can be met, and dynamic adjustment of link resources is realized.

When communication is carried out among the radio stations, all the sub-channels are communication channels;

when the radio station needs to carry out inter-station ranging or time synchronization with other radio stations, a sub-channel is divided into measuring channels, and pseudo code modulation measuring signals are transmitted to realize inter-station measurement.

Preferably, said module M2 comprises:

module M2.1: aiming at the anti-interference requirement of military radio station work, a signal modulation mode of subcarrier frequency hopping OFDM is adopted to realize the anti-interference, anti-interception and multi-waveform compatible construction requirements.

Selecting a subcarrier frequency hopping OFDM structure in a mode of combining frequency hopping and OFDM systems;

preferably, said module M2 comprises:

module M2.2: and generating a frequency modulation map of system frequency hopping through the chaotic sequence, and then completing the mapping process of the sub-carrier in the modulation process of the baseband OFDM.

Compared with an OFDM system based on radio frequency hopping, the method has the characteristics of easy digitization, simple realization, easy increase of frequency hopping points, high frequency spectrum utilization rate and strong concealment.

Based on the flexible configuration characteristic of multiple subcarriers of OFDM signals, the method can meet the requirements of narrowband and broadband frequency hopping signal waveform construction. When the waveform is generated, the bandwidth regulating bandwidth interval and the subcarrier channel bandwidth are determined according to the signal bandwidth condition and the requirement, and different signal transmission rate requirements can be adapted by distributing different numbers of subcarriers to users and matching with modulation modes with different orders. Specifically, aiming at the subcarrier FH-OFDM technology of broadband signals, in the frequency hopping process, the frequency points of a plurality of subcarriers are selected in a broadband through the generation of frequency hopping patterns, and the broadband frequency hopping sending process is completed; aiming at the subcarrier FH-OFDM technology of the narrowband signal, the subcarrier to be selected is generated according to a relatively large frequency hopping frequency point range, and the narrowband signal is modulated on the subcarrier of the fixed frequency point to complete broadband frequency hopping, so that the anti-interference purpose is achieved.

For the subcarrier allocation of different radio stations, a subcarrier interleaving aggregation strategy is adopted, namely, different radio station signals are formed by the aggregation of discontinuous subcarriers in a frequency hopping bandwidth range, and meanwhile, a better frequency diversity effect can be further obtained, and the radio station navigation communication has stronger interception resistance and interference resistance.

Preferably, said module M3 comprises:

module M3.1: in the aspect of measuring signal construction, the ranging and clock error measurement based on a spread spectrum measurement channel is realized by utilizing the time-frequency characteristics of OFDM and combining the perfect autocorrelation and cross-correlation characteristics of a CAZAC sequence.

CAZAC sequences are known as constant-envelope autocorrelation sequences and have the following characteristics:

1. constant envelope property. The amplitude of any CAZAC sequence is constant, and the characteristic can ensure that each frequency point in corresponding bandwidth experiences the same excitation, thereby facilitating the realization of unbiased estimation in coherent detection.

2. Ideal periodic autocorrelation properties. The name correlation peak is sharp for any CAZAC original sequence and the complementary correlation name correlation peak of the sequence obtained after circularly shifting n bits.

3. Good mutual characteristics. Namely, the cross correlation and partial correlation values are close to zero, so that the receiving end can accurately detect the required signal and reduce detection errors.

4. Low peak-to-average ratio (PAPR/CM). The ratio of the expected mean of the peaks of the time domain signal composed of any CAZAC sequence is low, thereby facilitating the implementation of the power amplifier.

5. The fourier transform is still followed by a CAZAC sequence. Any CAZAC sequence remains a CAZAC sequence after fourier transform/inverse fourier transform (FFT/IFFT), having all the properties of a CAZAC sequence.

Due to the excellent autocorrelation characteristic, the receiving end can extract accurate measurement information from the sequence conveniently, so that the distance information can be calculated accurately; meanwhile, due to the good cross-correlation characteristic, the multi-address capability of the radio station is superior in military radio stations, and the system capacity can be effectively improved; the CAZAC sequence is selected as the sending data, so that the OFDM signal can achieve a smaller peak-to-average ratio, and the problem of high inherent peak-to-average ratio of the OFDM signal can be solved.

The CAZAC sequence selected by the project is a Zadoff-Chu sequence (ZC sequence), and the mathematical expression of the CAZAC sequence is as follows:

wherein N is the sequence length, k is 0,1, …, N-1, j²R is any positive integer coprime to N. The autocorrelation curve of the CAZAC sequence with N839 is as follows, and good autocorrelation performance can be seen from the figure.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention can efficiently and reliably realize the communication and navigation functions;

2. the invention can still have strong anti-interception, anti-decoding and anti-interference capabilities under the severe channel environment;

3. the invention has reasonable flow structure and convenient use, and can overcome the defects of the prior art;

4. the invention can make the radio station still have strong anti-interception, anti-decoding and anti-interference capability under the severe channel environment.

5. The invention can ensure that the navigation system has a high-efficiency and reliable navigation function when the communication is reliable.

6. The invention fully combines the advantages of excellent anti-interference performance of FH (Frequency-Hopping) communication system, outstanding anti-multipath fading capability of OFDM (Orthogonal Frequency Division multiplexing) technology and high transmission rate.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

fig. 1 is a schematic diagram of the principle of a military radio station communication navigation integrated waveform construction scheme in the embodiment of the invention.

Fig. 2 is a schematic diagram of a spectrum allocation scheme of a navigation sub-channel and a communication sub-channel according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of a subcarrier hopping aggregation signal principle in an embodiment of the present invention.

Fig. 4 is a schematic diagram of CAZAC sequence autocorrelation in an embodiment of the present invention.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

The waveform structure of the military radio station combines the superior anti-interference performance of an FH (Frequency-Hopping) communication system, the outstanding anti-multipath fading capability and high transmission rate of an OFDM (Orthogonal Frequency Division Multiplexing) technology, the good autocorrelation and cross-correlation characteristics of a CAZAC (Const Amplitude Zero Auto-correlation) sequence and the outstanding characteristics of direct spread spectrum modulation in the aspects of anti-interference and system gain improvement, and various key technologies are fused to form the military radio station self-adaptive navigation communication integrated waveform structure based on the FH-OFDM technology, so that the new generation military radio station still has strong anti-interception, anti-decoding and anti-interference capabilities under the severe channel environment, and the communication and navigation functions are efficiently and reliably realized.

As shown in fig. 1-4, a FH-OFDM-based navigation communication integrated signal waveform includes three parts, namely an OFDM multi-carrier signal, a subcarrier hopping signal and a measurement signal, and is constructed by the following steps:

step 1: construction and conduction integrated OFDM multi-carrier signal

The OFDM divides the whole signal bandwidth into a plurality of sub-channels, and by adjusting the structures of different sub-channel transmission signals, different service functions such as measurement and communication can be met, and the dynamic adjustment of link resources is realized. When communication is carried out among the radio stations, all the sub-channels are communication channels; when the radio station needs to carry out inter-station ranging or time synchronization with other radio stations, a sub-channel is divided into measuring channels, and pseudo code modulation measuring signals are transmitted to realize inter-station measurement.

Step 2: a subcarrier hopping OFDM signal is constructed.

Aiming at the anti-interference requirement of military radio station work, a signal modulation mode of subcarrier frequency hopping OFDM is adopted to realize the anti-interference, anti-interception and multi-waveform compatible construction requirements.

And selecting a subcarrier frequency hopping OFDM structure in the mode of combining the frequency hopping and the OFDM system. And generating a frequency modulation map of system frequency hopping through the chaotic sequence, and then completing the mapping process of the sub-carrier in the modulation process of the baseband OFDM. Compared with an OFDM system based on radio frequency hopping, the method has the characteristics of easy digitization, simple realization, easy increase of frequency hopping points, high frequency spectrum utilization rate and strong concealment.

Based on the flexible configuration characteristic of multiple subcarriers of OFDM signals, the method can meet the requirements of narrowband and broadband frequency hopping signal waveform construction. When the waveform is generated, the bandwidth regulating bandwidth interval and the subcarrier channel bandwidth are determined according to the signal bandwidth condition and the requirement, and different signal transmission rate requirements can be adapted by distributing different numbers of subcarriers to users and matching with modulation modes with different orders. Specifically, aiming at the subcarrier FH-OFDM technology of broadband signals, in the frequency hopping process, the frequency points of a plurality of subcarriers are selected in a broadband through the generation of frequency hopping patterns, and the broadband frequency hopping sending process is completed; aiming at the subcarrier FH-OFDM technology of the narrowband signal, the subcarrier to be selected is generated according to a relatively large frequency hopping frequency point range, and the narrowband signal is modulated on the subcarrier of the fixed frequency point to complete broadband frequency hopping, so that the anti-interference purpose is achieved.

For the subcarrier allocation of different radio stations, a subcarrier interleaving aggregation strategy is adopted, namely, different radio station signals are formed by the aggregation of discontinuous subcarriers in a frequency hopping bandwidth range, and meanwhile, a better frequency diversity effect can be further obtained, and the radio station navigation communication has stronger interception resistance and interference resistance.

Step three: constructing a measurement signal based on an OFDM + CAZAC sequence

In the aspect of measuring signal construction, the time-frequency characteristics of OFDM are used, and the perfect autocorrelation and cross-correlation characteristics of CAZAC sequences are combined to realize the ranging and clock error measurement based on the spread spectrum measurement channel.

CAZAC sequences are known as constant-envelope autocorrelation sequences and have the following characteristics:

constant envelope property. The amplitude of any CAZAC sequence is constant, and the characteristic can ensure that each frequency point in corresponding bandwidth experiences the same excitation, thereby facilitating the realization of unbiased estimation in coherent detection.

Ideal periodic autocorrelation properties. The name correlation peak is sharp for any CAZAC original sequence and the complementary correlation name correlation peak of the sequence obtained after circularly shifting n bits.

Good mutual characteristics. Namely, the cross correlation and partial correlation values are close to zero, so that the receiving end can accurately detect the required signal and reduce detection errors.

Low peak-to-average ratio (PAPR/CM). The ratio of the expected mean of the peaks of the time domain signal composed of any CAZAC sequence is low, thereby facilitating the implementation of the power amplifier.

The fourier transform is still followed by a CAZAC sequence. Any CAZAC sequence remains a CAZAC sequence after fourier transform/inverse fourier transform (FFT/IFFT), having all the properties of a CAZAC sequence.

Due to the excellent autocorrelation characteristic, the receiving end can extract accurate measurement information from the sequence conveniently, so that the distance information can be calculated accurately; meanwhile, due to the good cross-correlation characteristic, the multi-address capability of the radio station is superior in military radio stations, and the system capacity can be effectively improved; the CAZAC sequence is selected as the sending data, so that the OFDM signal can achieve a smaller peak-to-average ratio, and the problem of high inherent peak-to-average ratio of the OFDM signal can be solved.

The CAZAC sequence selected by the project is a Zadoff-Chu sequence (ZC sequence), and the mathematical expression of the CAZAC sequence is as follows:

wherein N is the sequence length, k is 0,1, …, N-1, j²R is any positive integer coprime to N. The autocorrelation curve of the CAZAC sequence with N839 is as follows, and good autocorrelation performance can be seen from the figure.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.