Polarization independent coherent detection photonic terahertz communication method and system

Abstract

The application discloses a polarization-independent coherent detection photonic terahertz communication method and relates to the technical field of terahertz communication, and comprises the following steps: mapping an original data stream to be transmitted into an original vector signal, then generating two-way signals by encoding the original vector signal through Alamouti, generating double-polarization signals by passing the two-way signals through a double-polarization IQ modulator; generating terahertz signals by passing the double-polarization signals through optical heterodyne frequency after coupling with local light signals; mixing the terahertz signals with radio frequency signals after converging the terahertz signals, realizing down-conversion of the terahertz signals, and obtaining intermediate frequency signals; obtaining correction signals by passing the collected intermediate frequency signals through down-conversion, matching filtering and carrier phase recovery; and obtaining the original data stream to be transmitted by adopting an Alamouti-MIMO decoding method according to the correction signals. The application further discloses a polarization-independent coherent detection photonic terahertz communication system, and the application supports low-complexity and low-cost polarization-insensitive photonic-assisted terahertz communication.

Description

Technical Field

[0001] This invention relates to the field of terahertz communication technology, and in particular to a polarization-independent coherent detection photon terahertz communication method and system. Background Technology

[0002] In the vision and technology roadmap of 6G development, terahertz communication is widely regarded as a core component of future 6G mobile communication systems. Photonic-assisted terahertz communication systems (i.e., photonic terahertz communication systems), with their ability to seamlessly integrate fiber optic and terahertz links and their advantages of high capacity and ultra-wide bandwidth, are increasingly becoming a research focus. Photonic-assisted terahertz communication systems use optical heterodyne beat frequency generation (i.e., the coupled signal light and local oscillator light are fed together into a photodetector for beat frequency generation). The adjustable signal frequency range covers the entire terahertz band, resulting in high spectrum resource utilization. It has broad application prospects in future high-capacity communication, inter-satellite communication, and integrated space-ground communication.

[0003] However, for traditional photon-assisted terahertz communication systems, the polarization alignment between the two beams needs to be carefully considered when performing optical heterodyne beat frequency. During transmission, factors such as fiber optic transmission, mechanical stress, and temperature changes can cause polarization mismatch between the signal light and the local oscillator light. This mismatch results in an angular deviation from the local oscillator light direction when the signal light enters the coupler, leading to power degradation in the generated terahertz signal and thus polarization sensitivity issues (such as…). Figure 2 As shown in (a) in the diagram, even in extreme cases, when two beams of light are orthogonal, the power of the terahertz signal generated by the beat frequency will be completely lost, and it will be unable to carry any effective information. Therefore, at the current communication system architecture level, it is inevitable to use polarization controllers or polarization tracking algorithms to actively control the polarization state of the signal to be consistent with the direction of the local oscillator light, or to use polarization diversity optical heterodyne detection systems to maintain system performance and solve the polarization sensitivity problem.

[0004] While the two methods mentioned above can address the polarization sensitivity issue, the application of polarization controllers cannot guarantee long-term system stability, requiring real-time manual monitoring of the signal polarization state. This approach is not a permanent solution. Polarization tracking algorithms typically involve complex tracking processes and feedback mechanisms, significantly increasing system complexity and reducing robustness. Furthermore, polarization diversity optical heterodyne detection systems require additional optical components (such as polarization beam splitters and optical couplers), increasing system cost and reducing optical detection sensitivity. Therefore, current photon-assisted terahertz communication systems urgently need a low-complexity, cost-effective polarization-insensitive solution to improve system reliability and operability. Summary of the Invention

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a polarization-independent coherent detection photonic terahertz communication method and system, which is based on Alamouti encoding technology and combines the proposed Alamouti-MIMO decoding algorithm based on polarization-independent theory.

[0006] The present application solves the above technical problems by using the following technical solutions:

[0007] According to the polarization-independent coherent detection photonic terahertz communication method proposed by the present application, the original data stream to be transmitted is mapped into an original vector signal, and the original vector signal is encoded by Alamouti to generate two signals, which are subjected to double-polarization IQ modulation to generate double-polarization signals.

[0008] The original data stream to be transmitted is mapped into an original vector signal, and the original vector signal is encoded by Alamouti to generate two signals, which are subjected to double-polarization IQ modulation to generate double-polarization signals.

[0009] After the double-polarization signals are coupled with the local light signals, terahertz signals are generated by optical heterodyne frequency mixing.

[0010] After the terahertz signals are converged, they are mixed with radio frequency signals to achieve down-conversion of the terahertz signals and obtain intermediate frequency signals.

[0011] The collected intermediate frequency signals are subjected to down-conversion, matched filtering, and carrier phase recovery to obtain a correction signal.

[0012] According to the correction signal, an Alamouti-MIMO decoding method is used to obtain the original data stream to be transmitted, wherein the Alamouti-MIMO decoding method comprises:

[0013] The correction signal is subjected to odd-even data block separation to obtain odd block signals and even block signals, the even block signals are conjugated, and the conjugated even block signals and the odd block signals are subjected to Volterra-MIMO equalization to recover the original vector signal, and the original data stream to be transmitted is obtained by demapping.

[0014] A polarization-independent coherent detection photonic terahertz communication system comprises:

[0015] The optical transmitter is used to map the original data stream to be transmitted into an original vector signal, and then encode the original vector signal by Alamouti to generate two signals, which are subjected to double-polarization IQ modulation to generate double-polarization signals, and the double-polarization signals are output to an optical-wireless conversion module.

[0016] An optical-wireless conversion module is configured to couple a dual-polarization signal with a local light signal to generate a terahertz signal through optical heterodyne frequency mixing, and output the terahertz signal to a terahertz wireless receiver;

[0017] The terahertz wireless receiver is configured to mix the terahertz signal with a radio frequency signal after converging the terahertz signal to realize down-conversion of the terahertz signal, obtain an intermediate frequency signal, and output the intermediate frequency signal to a processing module;

[0018] The processing module is configured to obtain a correction signal through down-conversion, matched filtering, and carrier phase recovery of the collected intermediate frequency signal, separate the correction signal into odd block signals and even block signals through odd-even data block separation, take a conjugate of the even block signals, and recover the original vector signal through Volterra-MIMO equalization of the even block signals and the odd block signals together, and demap the original vector signal to obtain the original data stream.

[0019] As a further optimization scheme of the polarization-independent coherent detection photonic terahertz communication system, in the optical-wireless conversion module, the dual-polarization signal generated based on Alamouti encoding is coupled with a local light signal to generate a terahertz signal through optical heterodyne frequency mixing, the terahertz signal is amplified by a terahertz low-noise amplifier and then transmitted through a high-gain antenna, the conversion from light to terahertz wireless signal is completed, and the terahertz wireless signal is transmitted to the terahertz wireless receiver through a wireless link.

[0020] As a further optimization scheme of the polarization-independent coherent detection photonic terahertz communication system, in the terahertz wireless receiver, the terahertz signal is converged and then received by a horn antenna, the terahertz signal is amplified by a low-noise amplifier and then mixed with a frequency-doubled radio frequency signal in a terahertz frequency mixer to realize down-conversion of the terahertz signal, an intermediate frequency signal is obtained, and the intermediate frequency signal is amplified by an electrical amplifier and then input to the processing module.

[0021] As a further optimization scheme of the polarization-independent coherent detection photonic terahertz communication system, the processing module includes a receiving end signal acquisition module, a down-conversion module, a matched filtering module, a carrier phase recovery module, an odd-even data separation module, an even block signal conjugate module, a Volterra-MIMO equalization module, and a signal demapping module.

[0022] The receiving end signal acquisition module is configured to acquire the intermediate frequency signal amplified by the electrical amplifier.

[0023] The down-conversion module is configured to convert the intermediate frequency signal to a baseband signal, and output the baseband signal to the matched filtering module.

[0024] The matched filtering module and the carrier phase recovery module are configured to perform matched filtering and carrier phase recovery on the baseband signal to obtain a correction signal.

[0025] a parity data separation module, configured to separate the correction signal into odd block signals and even block signals according to parity data blocks;

[0026] an even block signal conjugate module, configured to take the conjugate of the even block signal and use the conjugate of the even block signal and the odd block signal as two inputs of a Volterra-MIMO equalization module;

[0027] a Volterra-MIMO equalization module, configured to recover the original vector signal by using a linear equalization method, and output the original vector signal to a signal demapping module;

[0028] a signal demapping module, configured to demap the original vector signal to obtain the original data stream transmitted.

[0029] Compared with the prior art, the above technical scheme has the following technical effects:

[0030] (1) On the one hand, the polarization-independent coherent detection photonic terahertz communication system can realize signal decoding and recover the original vector signal by using the designed Alamouti-MIMO decoding algorithm under different polarization states.

[0031] (2) The polarization-independent coherent detection photonic terahertz communication system simplifies the coherent detection photonic terahertz communication scheme on the basis of realizing polarization-independent transmission, only needs a set of photodetectors at the system transmitting end, and no longer needs additional polarization-related devices (such as a polarization controller, a polarization beam splitter, etc.), thereby reducing the system cost and improving the receiving sensitivity. The scheme no longer needs to consider the polarization state of the system, can maintain the performance of the system under long-time operation, has high stability and robustness, and can well adapt to the development of future long-distance communication systems. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The modulation and demodulation processing flow of the polarization-independent coherent detection photonic terahertz communication system based on Alamouti encoding provided for the example of the present application;

[0033] Figure 2 The schematic diagram of the formation principle of the polarization-sensitive problem of the traditional scheme and the schematic diagram of the polarization-independent implementation principle based on Alamouti encoding are provided for the example of the present application; wherein (a) is the schematic diagram of the formation principle of the polarization-sensitive problem of the traditional scheme, and (b) is the schematic diagram of the polarization-independent implementation principle based on Alamouti encoding;

[0034] Figure 3 The structure schematic diagram of the polarization-independent coherent detection photonic terahertz communication system based on Alamouti encoding provided for the example of the present application;

[0035] Figure 4A structure schematic diagram of a light transmitter of a polarization-independent coherent detection photonic terahertz communication system provided by the present application is provided for the example of the present application.

[0036] Figure 5 A flowchart of an algorithm of a DSP processing module of a polarization-independent coherent detection photonic terahertz communication system provided by the present application is provided for the example of the present application.

[0037] Figure 6 A structure diagram of a simplified polarization-independent coherent detection photonic terahertz communication system based on Alamouti encoding provided by the present application is provided for the example of the present application.

[0038] The reference signs are explained as follows: 11, a light transmitter of a polarization-independent system based on Alamouti encoding, 12, an optical fiber link, 13, an optical-terahertz conversion module, 21, a terahertz signal wireless receiver, 22, a DSP processing module of a polarization-independent system based on Alamouti encoding, 131, an optical coupler, 132, a local laser, 133, a photodetector, 134, a terahertz low-noise amplifier, 135, a high-gain antenna, 211, a horn antenna, 212, a terahertz low-noise amplifier, 213, a radio frequency source, 214, a terahertz frequency mixer, 215, an electric amplifier.

[0039] 111, a vector signal generation module, 112, an Alamouti encoding processing module, 113, a dual-polarization IQ modulator, 114, a transmitting-end laser.

[0040] 221, a receiving-end signal collection module, 222, a frequency down-conversion module, 223, a matched filter module, 224, a carrier phase recovery module, 225, an odd-even data separation module, 226, an even block signal conjugate module, 227, a Volterra-MIMO equalization module, 228, a signal demapping module. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be described in detail below with reference to the drawings and specific embodiments.

[0042] A processing flow of a polarization-independent coherent detection photonic terahertz communication system based on Alamouti encoding provided by the present application is provided for the example of the present application as shown in Figure 1As shown, in the optical transmitter, the original data stream to be transmitted is mapped into an original vector signal by a Matlab offline program, and then two signals carrying the same information content but different forms are generated by Alamouti encoding, and the two signals are then subjected to double polarization IQ modulators (DP-IQ modulators) to generate double polarization signals. When encoding, the different responses of the modulator to odd and even signals are considered, and more serious inter-symbol interference that is difficult to be compensated by an equalizer is introduced at the junction of the odd and even data blocks. The form of block encoding is adopted to reduce the performance influence caused by the inter-symbol interference. The double polarization signals obtained in this way of encoding and modulation can be carried on the same optical carrier, and the performance loss can be compensated for each other when the local light is projected, so that the polarization sensitivity problem is solved.

[0043] In the optical-wireless conversion module, the double polarization signals generated based on the Alamouti encoding are coupled with the local light signals, and then the terahertz signals are generated by optical heterodyne frequency, amplified by a terahertz low noise amplifier, and then transmitted by a high gain antenna, so as to complete the conversion of the optical signal into the terahertz wireless signal, and then transmitted through the wireless link.

[0044] In the terahertz wireless receiver, the divergent terahertz signals are converged and received by a horn antenna, and then amplified by a low noise amplifier to compensate for the free space path loss, and then mixed with the frequency-doubled radio frequency signals in a terahertz mixer to realize the down-conversion of the terahertz signals, and obtain an intermediate frequency signal. The intermediate frequency signal is amplified by an electric amplifier and received and collected by a digital storage oscilloscope.

[0045] In the DSP processing module, the collected intermediate frequency signal is first down-converted to obtain a baseband signal, the baseband signal is subjected to matched filtering, and then a carrier phase recovery algorithm (CPE) is used for frequency offset and phase compensation; finally, the processed signal is sent into the Alamouti-MIMO decoding algorithm module designed according to the polarization-independent theory in the application, to restore the original vector signal and demap the original data stream transmitted, and to calculate the bit error rate and other related results.

[0046] The polarization-independent photonic terahertz communication system provided by the application is a polarization-insensitive solution with low complexity and high cost-effectiveness, which can maintain the stability of the system performance for a long time under the premise that the system polarization state is not sensitive, and improve the reliability and operability of the system.

[0047] The polarization-independent photonic terahertz communication system provided by the application can maintain the stability of the system performance for a long time under the premise that the system polarization state is not considered, and the related principle is as follows Figure 2(b) in FIG. 1. In the traditional single polarization system, the signal light is affected by optical devices, temperature, etc. during transmission, resulting in polarization rotation, and when incident on the coupler, it is not in the same plane as the local oscillator signal, which needs to be projected to the local oscillator signal, resulting in a loss in power of the generated terahertz signal. Figure 2 (a) in FIG. 1 shows the power change of the four different polarization states in the traditional single polarization system after coupling with the local oscillator light. After Alamouti encoding, two signals carrying the same information but in different forms are generated, and when coupled with the local oscillator light, both polarization signals are projected to the local oscillator signal direction, which can be seen from Figure 2 (b) in FIG. 1. The two sets of signals can compensate for the loss in power.

[0048] To further improve the credibility of the scheme, the polarization-independent principle is theoretically derived. The original vector signal is encoded by the DP-IQ modulator to generate a dual-polarization signal. Assuming that the original vector signal SP = [S1 S2 S3 S4 …… S i ], the signals E x and E y carried on two different polarizations (denoted as X polarization and Y polarization) after Alamouti encoding can be represented as E x = [S1-S2 * S3-S4 * ……], E y = [S2 S1 * S4S3 * ……], respectively, for simplicity, the following two symbol blocks are taken as examples. H = [h xx h xy ; h yx h yy ] represents the channel response of the optical fiber, where h xx represents the influence coefficient between signals on the X polarization, h xy represents the influence coefficient of signals on the X polarization on signals on the Y polarization, h yx represents the influence coefficient of signals on the Y polarization on signals on the X polarization, and h yy represents the influence coefficient between signals on the Y polarization. Then, the signals arriving at the optical coupler 131 after transmission through the optical fiber can be represented as:

[0049]

[0050] where S i represents the i-th vector signal block, i = 1, 3, 5, … represents an odd block, and i = 2, 4, 6, … represents an even block, E x ′ , E y′ represents the signals carried on two polarizations after being affected by polarization rotation during transmission. The Alamouti encoded data pairs [S1-S2 * ] and [S2 S1 * ] are transmitted on X and Y polarizations simultaneously, and '*' represents conjugation.

[0051] When coupled with the local oscillator light, assuming the angle between the local oscillator light and the X polarization direction of the incident signal is θ (θ ∈ [-90°, 90°]), as shown in (b) of FIG. 6, Figure 2 after simple optical heterodyne detection based on a single photodetector UTC-PD without polarization diversity, the signals on the two polarization states will be projected onto the local oscillator light direction with a coefficient related to the polarization rotation angle θ, and the superimposed terahertz signal E oc = cosθ × E x ′ + sinθ × E y ′ Accordingly, the first odd block and the first even block of the generated terahertz signal (i.e., E oc ) can be represented as:

[0052]

[0053] where S odd is the odd block of the projected and superimposed signal, S even is the even block of the projected and superimposed signal, 'T' represents transposition, and '×' represents multiplication.

[0054]

[0055] As shown in the above formula, the even block signal is conjugated, and after rearrangement, it can be found that the conjugated signal and the original vector signal present a matrix transformation relationship, and H1 is the transformation matrix. It can be further found that the determinant result of H1 |H1| = -|h xx cosθ + h yx sinθ| 2 - |h xy cosθ + h yy sinθ| 2 is not zero, indicating that the processed signal and the original vector signal are linear transformations, and the original vector signal can be recovered by an equalizer.

[0056] Thus, it is theoretically proved that the polarization-independent transmission using Alamouti encoding is feasible. In any polarization state of θ angle, the original vector signal can be recovered from the received [S odd S even * T ​The original vector signal [S1 S2] is recovered.

[0057] The polarization-independent transmission scheme can keep the system performance stable for a long time without polarization control or additional optical devices. A structure diagram of a polarization-independent coherent detection photonic terahertz communication system based on Alamouti encoding is shown in Figure 3 The polarization-independent system optical transmitter 11 based on Alamouti encoding, the optical fiber link 12, the optical-terahertz conversion module 13, the terahertz signal wireless receiver 21, and the polarization-independent system DSP processing module 22 based on Alamouti encoding are mainly composed.

[0058] The polarization-independent system optical transmitter 11 based on Alamouti encoding is used to generate double-polarization signals after Alamouti encoding. The same information but different forms of signals are carried on two polarizations, and the detailed structure is shown in Figure 4 The original first vector signal is generated by the vector signal generation module 111 and is sent to the Alamouti encoding processing module 112 to generate the second vector signal and the third vector signal according to the encoding rules. Due to the different responses of the double-polarization modulator to the odd and even symbols, a relatively serious inter-symbol interference is introduced at the junction of the odd and even data blocks. In order to reduce the performance impact of the inter-symbol interference, an Alamouti block encoding scheme is adopted, that is, a symbol block contains multiple symbols, and the encoding is performed in blocks. The generated two-way vector signals are sent to the double-polarization IQ modulator 113, which is driven by the transmitting laser 114 to generate double-polarization signals.

[0059] After the above-mentioned double-polarization signals are transmitted by the optical fiber link 12, they are coupled with the local light from the local laser 132 in the optical coupler 131 of the optical-wireless conversion end 13, and then the terahertz signal is generated by frequency mixing in the photodetector 133, completing the conversion from light to terahertz. In this process, the signals on the two polarization states are projected in the direction of the local light. The carrier frequency of the generated terahertz signal is equal to the interval between the center frequencies of the transmitting laser 114 and the local laser 132. Then, the terahertz signal generated by frequency mixing is amplified by the terahertz low-noise amplifier 134, transmitted by the high-gain antenna 135, received and collected by the wireless receiver 21 through the wireless link.

[0060] In the wireless receiver 21, the terahertz signal received by the horn antenna 211 is first amplified by the terahertz low-noise amplifier 212 to compensate for the severe free path loss in long-distance transmission. The radio frequency signal generated by the radio frequency source 213 is mixed with the terahertz signal in the terahertz mixer 214 after frequency multiplication, and is down-converted to an intermediate frequency signal. Subsequently, the intermediate frequency signal is amplified by the electric amplifier 215 and sent to the Alamouti coding-based polarization-independent system DSP processing module 22 to complete the recovery of the original vector signal and the calculation of the bit error rate and other related results. Figure 6 A simplified structure diagram of the Alamouti coding-based polarization-independent coherent detection photonic terahertz communication system provided for the examples of the present application is shown in the figure.

[0061] The DSP processing module algorithm flow of the polarization-independent coherent detection photonic terahertz communication system provided by the examples of the present application is shown in the figure. Figure 5 First, the intermediate frequency signal amplified by the electric amplifier 215 is collected by the receiving end signal collection module 221, and is frequency-converted to a baseband by the down-conversion module 222 for subsequent processing. Subsequently, the signal is sent to the matched filter module 223 for matched filtering, and then the carrier phase recovery module 224 is used to compensate for the frequency offset and phase noise effects during transmission. According to the polarization-independent theoretical derivation process, the Alamouti-MIMO decoding module is designed, mainly including the odd-even data separation module 225, the even block signal conjugate module 226, the Volterra-MIMO equalization module 227, and the signal demapping module 228. The data processed by the carrier phase recovery module 224 is sent to the odd-even data separation module 225 to separate the odd block signal and the even block signal, and the processed even block signal is sent to the even block signal conjugate module 226 to take the conjugate and serve as the input of the Volterra-MIMO equalization module 227 together with the processed odd block signal. The Volterra-MIMO equalization module 227 will use the conjugate-processed signal to present a linear relationship with the original vector signal, and use the training data of the odd block signal S 2k+1 and the even block signal S 2k+2 (k=0, 1, 2, 3,...) based on part of the original vector signal to assist in estimating the channel response H1, and uses a linear equalization method to recover the original vector signal. Finally, the original vector signal obtained by equalization is sent to the signal demapping module 228 to obtain the original data stream transmitted by the Alamouti coding-based polarization-independent system optical transmitter 11, and to calculate the bit error rate and other related results.

[0062] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A polarization independent coherent detection photonic terahertz communication method, characterized in that, The method comprises the steps of: mapping the original data stream to be transmitted into an original vector signal, and then generating two-way signals by Alamouti encoding the original vector signal, and then generating dual-polarization signals by dual-polarization IQ modulators; generating terahertz signals by optical heterodyne frequency mixing after coupling the dual-polarization signals with local light signals; down-converting the terahertz signals by mixing the terahertz signals with radio frequency signals after converging the terahertz signals, to obtain intermediate frequency signals; obtaining correction signals by down-converting, matched filtering, and carrier phase recovery on the collected intermediate frequency signals; obtaining the original data stream to be transmitted by Alamouti-MIMO decoding method according to the correction signals, wherein the Alamouti-MIMO decoding method comprises the steps of: separating the correction signals into odd block signals and even block signals by odd-even data block separation, taking the conjugate of the even block signals, and then recovering the original vector signal by Volterra-MIMO equalization method on the even block signals and the odd block signals together, and then obtaining the original data stream to be transmitted by demapping.

2. A polarization independent coherent detection photonic terahertz communication system, characterized in that, The method comprises the steps of: an optical transmitter is configured to map the original data stream to be transmitted into an original vector signal, and then generate two-way signals by Alamouti encoding the original vector signal, and then generate dual-polarization signals by dual-polarization IQ modulators, and then output the dual-polarization signals to an optical-wireless conversion module; the optical-wireless conversion module is configured to generate terahertz signals by optical heterodyne frequency mixing after coupling the dual-polarization signals with local light signals, and then output the terahertz signals to a terahertz wireless receiver; the terahertz wireless receiver is configured to down-convert the terahertz signals by mixing the terahertz signals with radio frequency signals after converging the terahertz signals, to obtain intermediate frequency signals and then output the intermediate frequency signals to a processing module; the processing module is configured to obtain correction signals by down-converting, matched filtering, and carrier phase recovery on the collected intermediate frequency signals, separate the correction signals into odd block signals and even block signals by odd-even data block separation, take the conjugate of the even block signals, and then recover the original vector signal by Volterra-MIMO equalization method on the even block signals and the odd block signals together, and then obtain the original data stream to be transmitted by demapping.

3. A polarization independent coherent detection photonic terahertz communication system according to claim 2, wherein, In the optical-wireless conversion module, the dual-polarization signals generated based on Alamouti encoding are coupled with local light signals to generate terahertz signals, which are amplified by a terahertz low-noise amplifier and then transmitted by a high-gain antenna, to complete the conversion of optical signals into terahertz wireless signals, and then transmitted to the terahertz wireless receiver through a wireless link.

4. The polarization independent coherent detection photonic terahertz communication system according to claim 2, wherein, In the terahertz wireless receiver, the terahertz signals are converged and then received by a horn antenna, and then amplified by a low-noise amplifier and mixed with frequency-doubled radio frequency signals in a terahertz mixer to down-convert the terahertz signals, to obtain intermediate frequency signals, which are then amplified by an electrical amplifier and input to the processing module.

5. The polarization independent coherent detection photonic terahertz communication system according to claim 2, wherein, The processing module comprises a receiver signal acquisition module, a down-conversion module, a matched filtering module, a carrier phase recovery module, an odd-even data separation module, an even block signal conjugate module, a Volterra-MIMO equalization module, and a signal demapping module; the receiver signal acquisition module is configured to acquire the intermediate frequency signals amplified by the electrical amplifier; a down-conversion module, configured to convert the intermediate frequency signal to a baseband signal and output the baseband signal to a matched filter module; the matched filter module and a carrier phase recovery module, configured to perform matched filtering and carrier phase recovery on the baseband signal to obtain a corrected signal; an odd-even data separation module, configured to separate the corrected signal into an odd block signal and an even block signal; an even block signal conjugate module, configured to take a conjugate of the even block signal and use the even block signal and the odd block signal as two inputs of a Volterra-MIMO equalization module; the Volterra-MIMO equalization module, configured to recover an original vector signal by using a linear equalization method, and output the original vector signal to a signal demapping module; the signal demapping module, configured to demap the original vector signal to obtain an original data stream.

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