MIMO (multiple input multiple output) transmission system based on optical frequency combing sources and wavelength division multiplexing

Abstract

The invention discloses an MIMO transmission system based on optical frequency combing sources and wavelength division multiplexing. The MIMO transmission system based on optical frequency combing sources and wavelength division multiplexing comprises a central station, a transmission module and a base station, wherein the central station comprises a laser source for generating laser signals, a optical frequency combing module for generating multiple optical frequency combing sources according to the laser signals, a first wavelength division multiplexing module for separating the multiple optical frequency combing sources into a plurality of single optical frequency combing sources one by one, a space-time coding module for generating multiple space-time coding signals according to multiple high-speed MIMO baseband signals, and a plurality of electro-optical modulating modules; every electro-optical modulating module generates at least one MIMO signal according to at least one optical frequency combing source and at least one time-space coding signal; the transmission module transmits the multiple MIMO signals output by the plurality of electro-optical modulating modules; the base station comprises a plurality of opto-electrical detecting modules and a plurality of MIMO antennas, every opto-electrical detecting module detects at least one MIMO signals, and every MIMO antenna transmits a single MIMO signal. The MIMO transmission system based on the optical frequency combing sources and the wavelength division multiplexing can achieve transmission and frequency conversion of multiple MIMO signals through a single laser source.

Description

technical field [0001] The invention relates to the technical field of signal transmission, in particular to a MIMO transmission system based on an optical frequency comb source and wavelength division multiplexing. Background technique [0002] Such as figure 1 As shown, the MIMO (multiple-input and multiple-output) antenna system refers to a technology that uses multiple antennas for communication at the wireless communication transmitter and receiver. There are three main applications of MIMO technology: transmission diversity, beam Forming and spatial multiplexing, transmission diversity refers to using multiple antennas to transmit the same information at the transmitting end, thereby obtaining higher gain than a single antenna at the receiving end; beamforming refers to using the spatial correlation of multi-antenna arrays to generate interference , so that the radiation points to a specific direction; spatial multiplexing refers to the use of space-time information b...

AI Technical Summary

Problems solved by technology

In this scheme, since there are only a limited number of polarization modes available, the number of MIMO antennas that can be transmitted by this scheme is also limited, and the multi-channel MIMO transmission can only be achieved by adding laser sources, and the cost of the system will also increase. As it increases, the scalability is poor

In addition, a MIMO transmission scheme based on WDM (Wavelength Division Multiplexing, wavelength division multiplexing) and RoF (Radio over Fiber, wireless transmission over optical)-DAS (Distributed Antenna System, distributed antenna system) is proposed in the second scheme. This solution realizes the transmission of 2.4GHz and 5GHz dual-frequency 2x2 MIMO signals by using two lasers. However, based on this principle, the number of MIMO is limited by the number of laser sources, which cannot meet the requirements of large-scale antennas.

In addition, scheme three realizes the all-optical generation and transmission of 2x2 MIMO signals based on the dense optical frequency comb source generated by the microring oscillator. In this scheme, an optical frequency comb source with a frequency interval of 312.5KHz and an arrayed waveguide grating are used (AWG) performs inverse Fourier transform (IFFT) transformation on the baseband digital signal to realize orthogonal frequency division multiplexing (OFDM) modulation, and then directly divides the modulated OFDM signal into two channels and modulates it onto two optical carriers. , after optical fiber transmission, it is transmitted through two antennas. This scheme realizes MIMO transmission in transmit diversity mode, but does not reflect the key application of optical frequency comb source in terms of MIMO number expansion and spatial multiplexing

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