Transmitting terminal unit and multi-carrier wireless communication system

Abstract

The utility model provides a transmitting terminal unit and a multi-carrier wireless communication system, and the transmitting terminal unit comprises an optical comb signal generation module which is used for generating an optical comb signal and outputting the optical comb signal to a wavelength division multiplexer; the orthogonal frequency division multiplexer outputs signals to the first rectangular filter and the second rectangular filter, the first rectangular filter outputs signals to the first orthogonal modulator, the first orthogonal modulator outputs modulated signals to the first dual-port Mach-Zehnder modulator, and the second dual-port Mach-Zehnder modulator outputs modulated signals to the second dual-port Mach-Zehnder modulator. The first dual-port Mach-Zehnder modulator outputs a signal to the Gaussian filter; the second rectangular filter outputs a signal to a second quadrature modulator, the second quadrature modulator outputs the modulated signal to a second dual-port Mach-Zehnder modulator, and the second dual-port Mach-Zehnder modulator outputs a signal to a third rectangular filter; and the Gaussian filter output signal and the third rectangular filter output signal are used for outputting filtered signals to the first combiner. The multi-carrier wireless communication system is provided with the transmitting terminal unit. According to the utility model, the efficiency of optical signals can be improved.

Description

Technical Field

[0001] This utility model relates to the field of wireless communication technology, specifically, to a transmitting terminal unit and a multi-carrier wireless communication system having such a transmitting terminal unit. Background Technology

[0002] Optical frequency combs are widely used in wireless communication systems. Currently, optical frequency combs have a wide range of applications in wavelength division multiplexing systems, optical frequency measurement, and optical arbitrary waveform generation.

[0003] Chinese invention patent CN115343867A discloses an optical frequency comb generation system. This system comprises an external cavity laser, a first signal source generation and signal processing module, a dual parallel Mach-Zehnder modulator, a first phase modulator, a second signal source generation and signal processing module, and a second phase modulator. The external cavity laser generates continuous light and emits it to the Mach-Zehnder modulator. The first signal source generation and signal processing module provides signal sources to the Mach-Zehnder modulator and the first phase modulator and performs signal processing, driving the Mach-Zehnder modulator to generate the first optical frequency comb and driving the first phase modulator to broaden the spectrum of the first optical frequency comb to obtain a second optical frequency comb. The second phase modulator, driven by the second signal source generation and signal processing module, adjusts the flatness of the second optical frequency comb to obtain a third optical frequency comb.

[0004] However, existing optical frequency comb generation systems generate optical comb signals with relatively little information, especially when the bandwidth is fixed, they cannot generate more frequency optical signals, which affects the efficiency of the optical signal. Summary of the Invention

[0005] The primary objective of this invention is to provide a transmitting terminal unit capable of containing more information under certain frequency band conditions.

[0006] The second objective of this invention is to provide a multi-carrier wireless communication system having the aforementioned transmitting terminal unit.

[0007] To achieve the aforementioned first objective, the transmitting terminal unit provided by this utility model includes an optical comb signal generation module for generating an optical comb signal and outputting the optical comb signal to a wavelength division multiplexer; an orthogonal frequency division multiplexer that outputs signals to a first rectangular filter and a second rectangular filter; the first rectangular filter outputs a signal to a first quadrature modulator; the first quadrature modulator outputs the modulated signal to a first two-port Mach-Zehnder modulator; the first two-port Mach-Zehnder modulator outputs a signal to a Gaussian filter; the second rectangular filter outputs a signal to a second quadrature modulator; the second quadrature modulator outputs the modulated signal to a second two-port Mach-Zehnder modulator; the second two-port Mach-Zehnder modulator outputs a signal to a third rectangular filter; and the output signals of the Gaussian filter and the third rectangular filter output the filtered signal to a first combiner.

[0008] As can be seen from the above scheme, the optical comb signal generated by the optical comb signal generation module is modulated by the first dual-port Mach-Zehnder modulator and the second dual-port Mach-Zehnder modulator, respectively, and then filtered by the output signal of the Gaussian filter and the third rectangular filter. After each filtering, the signals are combined and then emitted. In this way, an optical signal containing more information can be output under the condition that the frequency band of the optical comb signal is fixed, thereby improving the efficiency of the optical signal.

[0009] A preferred embodiment is that the wavelength division multiplexer outputs one optical signal to the beam splitter, and the beam splitter splits the optical signal and outputs it to the first dual-port Mach-Zehnder modulator and the second dual-port Mach-Zehnder modulator respectively.

[0010] Therefore, it can be seen that the optical signal output from the wavelength division multiplexer is output to the first dual-port Mach-Zehnder modulator and the second dual-port Mach-Zehnder modulator, so that the first dual-port Mach-Zehnder modulator and the second dual-port Mach-Zehnder modulator can use the optical signal to modulate the optical signal.

[0011] A further approach is to have the wavelength division multiplexer output at least one optical signal to the second combiner. Preferably, the second combiner also receives the optical signal output from the first combiner.

[0012] As can be seen, the multiple optical signals output by the wavelength division multiplexer are combined by the second combiner before being output, thus facilitating the output of optical signals by the transmitting terminal unit.

[0013] A further approach involves a second combiner that combines the received optical signals before outputting them to an erbium-doped fiber amplifier. Furthermore, the output of the erbium-doped fiber amplifier is connected to an erbium-doped fiber.

[0014] It can be seen that the optical signal output from the second combiner is amplified by the erbium-doped fiber amplifier and the erbium-doped fiber, so that the optical signal can meet the requirements of long-distance transmission.

[0015] A further approach is to include a continuous-wave laser as the optical comb signal generation module. The continuous-wave laser outputs a continuous laser signal to a polarization controller, which outputs a signal to a Mach-Zehnder modulator. The Mach-Zehnder modulator also receives a sine wave signal output from a sine wave generator and outputs the modulated signal to a wavelength division multiplexer.

[0016] Therefore, it can be seen that the continuous laser signal generated by the continuous wave laser can be modulated by the Mach-Zehnder modulator to obtain the optical comb signal. The optical comb signal generation module has a simple structure and low production cost.

[0017] A further approach is to use a Mach-Zehnder modulator to modulate the laser signal output by the polarization controller with a sine wave signal.

[0018] To achieve the second objective mentioned above, the multi-carrier wireless communication system provided by this utility model includes the aforementioned transmitting terminal unit, which outputs signals to at least one remote radio frequency unit.

[0019] As can be seen from the above scheme, the transmitting terminal unit transmits the optical signal to the remote radio frequency unit through the erbium-doped fiber, and the remote radio frequency unit demodulates and transmits it into the air.

[0020] The preferred embodiment is that the transmitting terminal unit and the remote radio frequency unit are connected by an uplink optical fiber and a downlink optical fiber.

[0021] Therefore, it can be seen that the transmitting terminal unit and the remote radio frequency unit can transmit signals bidirectionally. The transmitting terminal unit can both send signals to the remote radio frequency unit and receive signals from the remote radio frequency unit. Attached Figure Description

[0022] Figure 1 This is a structural block diagram of an embodiment of the multi-carrier wireless communication system of this utility model.

[0023] Figure 2 This is a structural block diagram of an embodiment of the transmitting terminal unit of this utility model.

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0025] The transmitting terminal unit of this utility model can generate optical comb signals, and the optical comb signals can carry a large amount of information. The multi-carrier wireless communication system includes the above-mentioned transmitting terminal unit and one or more radio frequency remote units. The optical signal output by the transmitting terminal unit is transmitted to the air through the antenna of the radio frequency remote unit.

[0026] See Figure 1 This embodiment includes a transmitting terminal unit 11 and an RF remote unit 12. A pair of optical fibers connects the transmitting terminal unit 11 and the RF remote unit 12. Specifically, the transmitting terminal unit 11 and the RF remote unit 12 transmit optical signals via a downlink optical fiber 13 and an uplink optical fiber 14. Preferably, both the downlink optical fiber 13 and the uplink optical fiber 14 are standard single-mode optical fibers, and their lengths are 30 kilometers. The optical comb signal generated by the transmitting terminal unit 11 is transmitted to the RF remote unit 12 via the downlink optical fiber 13. This optical comb signal contains multiple microwave signals of different frequencies.

[0027] Of course, in other embodiments, the number of radio frequency remote units 12 can be more than two. The transmitting terminal unit 11 can transmit optical signals to multiple radio frequency remote units through uplink optical fiber and downlink optical fiber respectively. Each radio frequency remote unit is equipped with a photodetector. The photodetector demodulates the received signal to form multiple microwave signals of different frequencies and transmits them into the air through an antenna.

[0028] See Figure 2 The transmitting terminal unit 11 has an optical comb signal generation module, which generates an optical comb signal. In this embodiment, the optical comb signal generation module includes a continuous-wave laser 21, which outputs a continuous-wave laser signal and transmits the output continuous-wave laser signal to a polarization controller 22. The polarization controller 22 adjusts the polarization state of the continuous-wave laser signal and outputs the polarization-adjusted continuous-wave laser signal to a Mach-Zehnder modulator 24. The Mach-Zehnder modulator 24 also receives a sine wave signal output by a sine wave generator 23 and modulates the continuous-wave laser signal using the sine wave signal generated by the sine wave generator 23 to obtain an optical comb signal. Since the Mach-Zehnder modulator 24 modulates the continuous-wave laser signal, the output optical comb signal contains multiple optical signals of different frequencies, and the frequency interval between two adjacent optical signals is equal. The Mach-Zehnder modulator 24 outputs the optical comb signal to a wavelength division multiplexer 30.

[0029] The transmitting terminal unit 11 also includes an orthogonal frequency division multiplexer 41. Preferably, the orthogonal frequency division multiplexer 41 is an orthogonal amplitude modulation orthogonal frequency division multiplexer used to divide the channel into multiple orthogonal sub-channels, thereby converting the high-speed data signal into parallel low-speed sub-data streams, which are then modulated onto each sub-channel for transmission. The orthogonal frequency division multiplexer 41 outputs signals to a first rectangular filter 42 and a second rectangular filter 52. The filtering frequency bands of the first rectangular filter 42 and the second rectangular filter 52 may be the same or different.

[0030] The first rectangular filter 42 outputs a signal to the first quadrature modulator 43, which has a frequency of 10 GHz. The first quadrature modulator 43 then outputs the modulated signal to the first two-port Mach-Zehnder modulator 45. Figure 1 As can be seen, one path of the signal output from the first quadrature modulator 43 is directly output to the first two-port Mach-Zehnder modulator 45, and the other path passes through the first electrical gain converter 44 before being output to the first two-port Mach-Zehnder modulator 45. In this embodiment, the gain of the first electrical gain converter 44 is -1. The switching bias voltage of the first two-port Mach-Zehnder modulator 45 is 4V, the switching RF voltage is 4V, and the bias voltages of the two ports are 1V and -1V, respectively. The first two-port Mach-Zehnder modulator 45 outputs the adjusted signal to the Gaussian filter 46. The center frequency of the Gaussian optical filter 46 is 193.1825THz, and the bandwidth is 9GHz.

[0031] The second rectangular filter 52 outputs a signal to the second quadrature modulator 53, which has a frequency of 5 GHz. The second quadrature modulator 53 then outputs the modulated signal to the second two-port Mach-Zehnder modulator 55. Figure 1 As can be seen, one path of the signal output from the second quadrature modulator 53 is directly output to the second two-port Mach-Zehnder modulator 55, and the other path passes through the second electrical gain unit 54 before being output to the second two-port Mach-Zehnder modulator 55. In this embodiment, the gain of the second electrical gain unit 54 is also -1. The switching bias voltage of the second two-port Mach-Zehnder modulator 55 is 4V, the switching RF voltage is 4V, and the bias voltages of the two ports are 2V and -2V, respectively. The second two-port Mach-Zehnder modulator 55 outputs the adjusted signal to the third rectangular filter 56, the center frequency of which is 193.1825THz and the bandwidth is 12GHz. Thus, the modulated signals output from the Gaussian filter 46 and the third rectangular filter 56 form two single-sideband modulated signals.

[0032] After receiving the optical comb signal, the wavelength division multiplexer 30 transmits the multiple optical signals of the optical comb signal through one channel respectively, and outputs one of the optical signals to the beam splitter 31. The beam splitter 31 splits the received optical signal into two paths and outputs them to the first dual-port Mach-Zehnder modulator 45 and the second dual-port Mach-Zehnder modulator 55 respectively. Preferably, the optical power of the optical signals output by the beam splitter 31 to the first dual-port Mach-Zehnder modulator 45 and the second dual-port Mach-Zehnder modulator 55 is equal. That is, the beam splitter 31 divides the optical power of the received optical signal equally and outputs it to the first dual-port Mach-Zehnder modulator 45 and the second dual-port Mach-Zehnder modulator 55 respectively.

[0033] The Gaussian filter 46 outputs the Gaussian-filtered optical signal to the first combiner 47, and the third rectangular filter 56 also outputs a rectangular-filtered signal to the first combiner 47. Therefore, the first combiner 47 actually receives the filtered optical signals output by the first dual-port Mach-Zehnder modulator 45 and the second dual-port Mach-Zehnder modulator 55, and combines the received optical signals, outputting the combined optical signal to the second combiner 32. Furthermore, the second combiner 32 also receives the multiple optical signals output by the wavelength division multiplexer 30, combines the received optical signals, and outputs the combined optical signal to the erbium-doped fiber amplifier 33. The output of the erbium-doped fiber amplifier 33 is connected to an erbium-doped fiber. The erbium-doped fiber amplifier 33 amplifies the optical power of the received optical signal and transmits it through the erbium-doped fiber to the radio frequency remote unit.

[0034] Since the signal output by the second combiner 32 includes both the multiple optical signals output from the wavelength division multiplexer 30 and the optical signals that have been modulated and filtered by Gaussian and rectangular filters respectively, the optical signal output by the second combiner 32 contains more information and can improve the efficiency of the optical signal under a certain frequency band.

[0035] Finally, it should be emphasized that the above are only preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A transmitting terminal unit, characterized in that, include: An optical comb signal generation module is used to generate an optical comb signal and output the optical comb signal to a wavelength division multiplexer; An orthogonal frequency division multiplexer outputs signals to a first rectangular filter and a second rectangular filter. The first rectangular filter outputs a signal to a first quadrature modulator. The first quadrature modulator outputs the modulated signal to a first two-port Mach-Zehnder modulator. The first two-port Mach-Zehnder modulator outputs a signal to a Gaussian filter. The second rectangular filter outputs a signal to the second quadrature modulator, the second quadrature modulator outputs the modulated signal to the second two-port Mach-Zehnder modulator, and the second two-port Mach-Zehnder modulator outputs a signal to the third rectangular filter; The output signals of the Gaussian filter and the third rectangular filter output signal will output the filtered signal to the first combiner.

2. The transmitting terminal unit according to claim 1, characterized in that: The wavelength division multiplexer outputs one optical signal to the beam splitter, which then splits the optical signal and outputs it to the first dual-port Mach-Zehnder modulator and the second dual-port Mach-Zehnder modulator, respectively.

3. The transmitting terminal unit according to claim 2, characterized in that: The wavelength division multiplexer outputs at least one optical signal to the second combiner.

4. The transmitting terminal unit according to claim 3, characterized in that: The second combiner also receives the optical signal output by the first combiner.

5. The transmitting terminal unit according to claim 4, characterized in that: The second combiner combines the received optical signals and outputs them to the erbium-doped fiber amplifier.

6. The transmitting terminal unit according to claim 5, characterized in that: The output end of the erbium-doped fiber amplifier is connected to an erbium-doped fiber.

7. The transmitting terminal unit according to any one of claims 1 to 6, characterized in that: The optical comb signal generation module includes a continuous wave laser, which outputs a continuous laser signal to a polarization controller. The polarization controller outputs a signal to a Mach-Zehnder modulator, which also receives a sine wave signal output by a sine wave generator. The Mach-Zehnder modulator outputs the modulated signal to the wavelength division multiplexer.

8. The transmitting terminal unit according to claim 7, characterized in that: The Mach-Zehnder modulator uses the sine wave signal to modulate the laser signal output by the polarization controller.

9. A multi-carrier wireless communication system, characterized in that, Includes a transmitting terminal unit as described in any one of claims 1 to 8, wherein the transmitting terminal unit outputs a signal to at least one remote radio frequency unit.

10. The multi-carrier wireless communication system according to claim 9, characterized in that: The transmitting terminal unit and the remote radio frequency unit are connected by an uplink optical fiber and a downlink optical fiber.

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