Thz wireless communication system based on solid state electronics for coherent reception without local oscillator

Abstract

The application discloses a terahertz local oscillator-free coherent receiving wireless communication system based on solid-state electronics, and belongs to the technical field of wireless communication. The system is composed of a transmitting end and a local oscillator-free receiving end. The transmitting end comprises a terahertz mixer, a terahertz amplifier, a terahertz diplex network, a terahertz dual-frequency transmitting antenna, a terahertz unequal power division network and a local oscillator signal. The local oscillator-free receiving end comprises a terahertz mixer, a terahertz amplifier, a terahertz diplex network, a terahertz dual-frequency receiving antenna and a gain control unit. Frequency isolation is realized by using a terahertz diplex, and spatial isolation is realized by using a terahertz dual-frequency antenna, so that the transmitting / receiving of the local oscillator signal and the terahertz radio frequency signal is realized at the same time, and finally the local oscillator-free receiving end is realized. The application realizes coherent receiving demodulation in the form of the local oscillator-free receiving end at the receiving end, reduces the complexity of the communication system, improves the performance of the system, and has the characteristics of low cost and low power consumption.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a terahertz coherent receiving wireless communication system based on solid-state electronics. Background Technology

[0002] With the rapid development of information technology, 6G mobile communication technology, and artificial intelligence technology, people's demand for information is increasing, and the requirements for information transmission bandwidth and latency are becoming increasingly stringent. The emergence of many new internet applications (such as mobile video streaming services, autonomous driving, and smart cities) will further drive the growth of network traffic. Preliminary analysis indicates that within the next decade, the total transmission rate of various spatial data and the demand rate for wireless data services will reach levels exceeding 100Gbps, making existing wireless information transmission rates increasingly insufficient to meet people's needs. The terahertz (THz) band, situated between millimeter waves and infrared light, possesses the advantages of both while also exhibiting its own unique strengths. These include high bandwidth under abundant spectrum resources, good penetration, low photon energy security, better directionality under narrow beams, and atmospheric attenuation characteristics. Terahertz communication technology can alleviate the current problems of scarce wireless communication spectrum and capacity limitations, creating favorable conditions for building a future high-capacity, high-bandwidth terahertz high-speed wireless communication backbone network, making it the preferred technology for achieving ultra-high-speed wireless communication in the future.

[0003] Currently, terahertz coherent wireless communication system architectures are mainly implemented using optical and solid-state electronics methods. Optical terahertz coherent wireless communication systems typically employ a combination of optoelectronics at the transmitter, such as combining it with a unidirectional moving carrier photodiode (UTC-PD), while requiring a separate optical fiber to transmit the local oscillator signal or providing an optical local oscillator signal at the receiver. This approach requires high-precision optical components and complex signal processing algorithms, and its system performance is often affected by a combination of factors, such as fiber nonlinearity, random optical perturbations, and grating-waveguide coupling mismatch. Furthermore, the system structure is complex, and the transmitter's power conversion efficiency is low. Solid-state electronics-based coherent wireless communication systems are structurally simpler than optical methods, but the local oscillator signal in the terahertz band is typically achieved through multi-stage frequency multiplication, which is expensive and may introduce frequency offset. Summary of the Invention

[0004] In view of this, a terahertz coherent receiving wireless communication system based on solid-state electronics is proposed. It adopts a receiver without a local oscillator to realize the terahertz coherent receiving wireless communication system, which reduces the complexity of the communication system, improves the system performance, and has the characteristics of low cost and low power consumption.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A terahertz coherent receiving wireless communication system based on solid-state electronics includes a transmitter and a receiver without a local oscillator. The transmitter comprises a terahertz mixer, a terahertz amplifier, a terahertz duplex network, a dual-frequency terahertz transmitting antenna, a terahertz unequal-division power divider network, and a local oscillator signal. The receiver without a local oscillator comprises a terahertz mixer, a terahertz amplifier, a terahertz duplex network, a dual-frequency terahertz receiving antenna, and a gain control unit.

[0007] Transmitter operation: The local oscillator signal is fed into a terahertz mixer and up-converted with the intermediate frequency signal through an unequal power divider network to form a terahertz modulated signal. This signal is then amplified by a terahertz amplifier. The other signal is fed into a terahertz duplex network and radiated into free space through a terahertz dual-frequency transmitting antenna.

[0008] Working process of the receiver without local oscillator: The local oscillator and terahertz modulation signals are received using a terahertz dual-frequency receiving antenna. The terahertz modulation signal and the local oscillator signal are separated through a terahertz duplex network. The local oscillator signal is obtained by the gain control unit to meet the power requirements of the local oscillator input of the terahertz mixer. The terahertz signal is amplified by the terahertz amplifier. The terahertz signal and the local oscillator signal are coherently demodulated in the terahertz mixer to obtain the intermediate frequency signal.

[0009] Furthermore, terahertz mixers can be implemented using fundamental frequency mixing or harmonic frequency mixing.

[0010] Furthermore, terahertz duplex networks can be implemented using microstrip lines, waveguides, and other methods.

[0011] Furthermore, terahertz dual-frequency transmit / receive antennas can be implemented using microstrip antennas, on-chip antennas, phased array antennas, Cassegrain antennas, and horn antennas.

[0012] Furthermore, the feature is that the terahertz mixer can be replaced by a terahertz IQ modulator / demodulator.

[0013] Furthermore, the antenna can be a dual-band antenna with the same aperture to transmit radio frequency and local oscillator signals, or two antennas can be used to transmit local oscillator signals and radio frequency signals respectively.

[0014] Furthermore, terahertz mixers and terahertz IQ modulators / demodulators can be implemented using a hybrid diode / transistor integrated circuit approach, or using a monolithic diode / transistor integrated circuit approach.

[0015] The beneficial effects of the above-mentioned technical solution adopted by the present invention are as follows:

[0016] 1. This invention achieves coherent demodulation without a local oscillator, which enables coherent signal transmission based on a high-order modulation format, while eliminating the need for an expensive terahertz local oscillator source, simplifying the receiver structure and reducing system complexity, cost, and power consumption.

[0017] 2. The receiver and transmitter of this invention use the same local oscillator signal, which reduces the impact of frequency offset and improves system performance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a local oscillator-free coherent receiving terahertz wireless communication system based on a terahertz mixer, according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of a local oscillator-free coherent receiving terahertz wireless communication system based on a terahertz IQ modulator, according to an embodiment of the present invention.

[0020] Figure 3 This is a schematic diagram of a usable terahertz dual-frequency antenna structure in an embodiment of the present invention.

[0021] Figure 4 This is a simulation result diagram of a duplexer that can be used in the 220GHz frequency band in an embodiment of the present invention.

[0022] Figure 5 This is a graph showing the signal-to-noise ratio variation under different frequency differences between the local oscillator frequencies of the transmitting and receiving ends in an embodiment of the present invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] A terahertz coherent receiving wireless communication system based on solid-state electronics includes a transmitter and a receiver without a local oscillator. The transmitter comprises a terahertz mixer, a terahertz amplifier, a terahertz duplex network, a dual-frequency terahertz transmitting antenna, a terahertz unequal-division power divider network, and a local oscillator signal. The receiver without a local oscillator comprises a terahertz mixer, a terahertz amplifier, a terahertz duplex network, a dual-frequency terahertz receiving antenna, and a gain control unit.

[0026] The transmitting end works as follows: the local oscillator signal is fed into a terahertz mixer and up-converted with the intermediate frequency signal through an unequal power divider network to form a terahertz modulated signal. This signal is then amplified by a terahertz amplifier. The other signal is fed into a terahertz duplex network and radiated into free space through a terahertz dual-frequency transmitting antenna.

[0027] The operation of the local oscillator-less receiver is as follows: The local oscillator and terahertz modulation signals are received using a terahertz dual-frequency receiving antenna. The terahertz modulation signal and the local oscillator signal are separated through a terahertz duplex network. The local oscillator signal is obtained by a gain control unit to meet the power requirements of the local oscillator input of the terahertz mixer. The terahertz signal is amplified by a terahertz amplifier. The terahertz signal and the local oscillator signal are coherently demodulated in the terahertz mixer to obtain the intermediate frequency signal.

[0028] Preferably, the terahertz mixer can be implemented using fundamental frequency mixing or harmonic frequency mixing.

[0029] Preferably, the terahertz duplex network can be implemented based on microstrip lines, waveguides, or other similar methods.

[0030] Preferably, the terahertz dual-frequency transmit / receive antenna can be implemented based on microstrip antennas, on-chip antennas, phased array antennas, Cassegrain antennas, and horn antennas.

[0031] Preferably, the terahertz mixer can be replaced by a terahertz IQ modulator / demodulator.

[0032] Preferably, the antenna can be a dual-band antenna with the same aperture to transmit radio frequency and local oscillator signals, or two antennas can be used to transmit local oscillator signals and radio frequency signals respectively.

[0033] Preferably, the terahertz mixer and terahertz IQ modulator / demodulator can be implemented based on a diode / transistor hybrid integrated circuit or based on a diode / transistor monolithic integrated circuit.

[0034] The following is a more specific embodiment:

[0035] like Figure 1 As shown in the embodiment, an oscillator-free coherent receiving terahertz wireless communication system structure based on a terahertz mixer is provided, including a transmitter and an oscillator-free receiver;

[0036] The transmitter includes a terahertz mixer, a terahertz amplifier, a terahertz duplex network, a terahertz dual-frequency transmitting antenna, a terahertz unequal-division power divider network, and a local oscillator signal;

[0037] The local oscillator-less receiver includes a terahertz mixer, a terahertz amplifier, a terahertz duplex network, a terahertz dual-frequency receiving antenna, and a gain control unit.

[0038] Transmitter operation: The local oscillator signal is fed into a terahertz mixer and up-converted with the intermediate frequency signal through an unequal power divider network to form a terahertz modulated signal. This signal is then amplified by a terahertz amplifier. The other signal is fed into a terahertz duplex network and radiated into free space through a terahertz dual-frequency transmitting antenna.

[0039] Working process of the receiver without local oscillator: The local oscillator and terahertz modulation signals are received using a terahertz dual-frequency receiving antenna. The terahertz modulation signal and the local oscillator signal are separated through a terahertz duplex network. The local oscillator signal is obtained by the gain control unit to meet the power requirements of the local oscillator input of the terahertz mixer. The terahertz signal is amplified by the terahertz amplifier. The terahertz signal and the local oscillator signal are coherently demodulated in the terahertz mixer to obtain the intermediate frequency signal.

[0040] The terahertz mixer can be implemented using fundamental frequency mixing or harmonic frequency mixing.

[0041] The terahertz duplex network can be implemented using microstrip lines, waveguides, or other methods.

[0042] The terahertz dual-frequency transmit / receive antenna can be implemented using microstrip antennas, on-chip antennas, phased array antennas, Cassegrain antennas, and horn antennas, among other methods.

[0043] The terahertz mixer can be replaced by a terahertz IQ modulator / demodulator.

[0044] The antenna can be a dual-band antenna with the same aperture to transmit radio frequency and local oscillator signals, or two antennas can be used to transmit local oscillator signals and radio frequency signals respectively.

[0045] The terahertz mixer and terahertz IQ modulator / demodulator can be implemented based on a diode / transistor hybrid integrated circuit or based on a diode / transistor monolithic integrated circuit.

[0046] In this embodiment, Figure 2 The structure of a local oscillator-free coherent reception terahertz wireless communication system is described, which is realized by using a terahertz IQ modulator / demodulator.

[0047] In this embodiment, Figure 3 This paper describes one method for connecting a terahertz dual-frequency receiving antenna to a terahertz full-duplex network. In this method, the local oscillator (LO) and radio frequency (RF) signals are transmitted independently through two different antennas, achieving spatial isolation between the LO and RF signals, and frequency isolation between the signals is achieved through the terahertz full-duplex network. Figure 4 The figure shown is a simulation result diagram of a terahertz duplexer for the 220GHz band that can be used in an embodiment of the present invention.

[0048] Coherent demodulation is achieved by multiplying and demodulating a carrier signal with a modulating signal of the same frequency and phase to obtain a baseband signal.

[0049] Baseband signal: s(t)=cosω s t

[0050] Carrier signal: cosω c t

[0051] Modulated signal: y(t)=s(t)·cosω c t

[0052] Coherent demodulated signal: m(t) = s(t)·cosω c t·cosω c t=1 / 2[s(t)+cos2ω c t]

[0053] As can be seen from the above equation, the baseband signal can be obtained by filtering out high-frequency components using a filter. Where, ω s ω is the angular frequency of the baseband signal. c This is the angular frequency of the carrier signal.

[0054] If the local oscillator signal and the carrier signal are out of phase, the demodulated signal m(t)

[0055]

[0056] As can be seen from the expression for m(t), the demodulated signal after filtering out high-frequency components... It can be seen that the demodulated baseband signal contains not only the baseband signal but also a cosine component, resulting in phase ambiguity. Here, θ represents the phase difference between the local oscillator signal and the carrier signal.

[0057] If the local oscillator signal and the carrier signal have different frequencies, the demodulated signal m(t)

[0058]

[0059] As can be seen from the expression for m(t), the demodulated signal after filtering out high-frequency components... It can be seen that the demodulated baseband signal contains not only the baseband signal but also a cosine component; only when ω... c1 =ω c2 Only when this is achieved can coherent demodulation be realized. Wherein, ω c1 ω is the angular frequency of the local oscillator signal. c2 This is the angular frequency of the carrier signal.

[0060] like Figure 5 As shown, this illustrates the signal-to-noise ratio variation of the transmitter local oscillator signal and the receiver local oscillator signal at different frequency differences obtained from actual measurements.

[0061] The specific embodiments described above illustrate the technical solution and beneficial effects of the present invention in detail. It should be understood that the above description is only the preferred embodiment of the present invention and does not limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A terahertz oscillator-free coherent receiving wireless communication system based on solid-state electronics, comprising a transmitter and an oscillator-free receiver, characterized in that, The transmitter includes a terahertz mixer, a terahertz amplifier, a terahertz duplex network, a terahertz dual-frequency transmitting antenna, a terahertz unequal-division power divider network, and a local oscillator signal. The transmitter operates as follows: the local oscillator signal is fed into the terahertz mixer through the unequal-division power divider network and up-converted with the intermediate frequency signal to form a terahertz modulated signal. This signal is then amplified by the terahertz amplifier. The other signal is fed into the terahertz duplex network and, together with the amplified terahertz modulated signal, is radiated into free space through the terahertz dual-frequency transmitting antenna. The local oscillator-less receiver includes a terahertz mixer, a terahertz amplifier, a terahertz duplex network, a terahertz dual-frequency receiving antenna, and a gain control unit. The local oscillator-less receiver operates as follows: the terahertz dual-frequency receiving antenna receives both the local oscillator and terahertz modulation signals; the terahertz duplex network separates the terahertz modulation signal from the local oscillator signal; the local oscillator signal passes through the gain control unit to obtain a signal that meets the power requirements of the local oscillator input of the terahertz mixer; the terahertz signal is amplified by the terahertz amplifier; and the terahertz signal and the local oscillator signal are coherently demodulated in the terahertz mixer to obtain an intermediate frequency signal.

2. The terahertz oscillatorless coherent receiving wireless communication system based on solid-state electronics according to claim 1, characterized in that, Terahertz mixers are implemented using fundamental frequency mixing or harmonic frequency mixing.

3. The terahertz oscillatorless coherent receiving wireless communication system based on solid-state electronics according to claim 1, characterized in that, Terahertz duplex networks are implemented using microstrip lines or waveguides.

4. The terahertz oscillatorless coherent receiving wireless communication system based on solid-state electronics according to claim 1, characterized in that, Terahertz dual-frequency transmit / receive antennas can be microstrip antennas, on-chip antennas, phased array antennas, Cassegrain antennas, or horn antennas.

5. The terahertz oscillatorless coherent receiving wireless communication system based on solid-state electronics according to claim 2, characterized in that, The terahertz mixer can be replaced with a terahertz IQ modulator / demodulator.

6. The terahertz oscillatorless coherent receiving wireless communication system based on solid-state electronics according to claim 4, characterized in that, The antenna uses a dual-band antenna with the same aperture to transmit radio frequency and local oscillator signals, or uses two antennas to transmit local oscillator signals and radio frequency signals respectively.

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