Mimo Radio-over-Fiber For Wireless Communication And Photonic Integration

The new generation of mobile communication proposes three major application scenarios:enhanced mobile broadband(e MBB),large-scale machine communication(m MTC),and ultra-reliable and low-latency(URLLC).To meet the needs mentioned above,the mobile communication system proposes applications of millimeter waves and increasing deployment of active antenna units to meet coverage.The traditional Common Public Radio Interface(CPRI)protocol can’t bear a tenfold increment in capacity,so it is of practical significance to design a new fronthaul link with a simple structure,large capacity,and support for millimeter wave signal transmission.Radio over Fiber(ROF)has the advantages of low loss,small size,and anti-electromagnetic interference,which is suitable for the above transmission scenarios.Researchers domestic and abroad have proposed many mobile fronthaul solutions based on ROF.At the same time,photonics integration technology becomes the future development trend of photonics because of its advantages of small size,low loss,and stable performance.In this paper,ROF technology and photonics integration technology are studied,while three high-spectrum Multiple-Input Multiple-Output(MIMO)millimeter-wave transmission mobile fronthaul schemes based on ROF is designed.The main research contents are as follows:The development of mobile communication and the background technological requirements of the current access network is expounded,while the ROF technology,photonic integration technology,and their advantages which meet the above technological requirements are introduced,and the relevant domestic and foreign research status are introduced at last.Then some key optical devices in ROF technology and their analysis of basic physical principles and mathematical models are detailed.Finally,some typical on-chip integrated optical devices are listed.A tunable dual-channel frequency multiplication MIMO millimeter-wave signal transmission scheme is studied.This scheme is oriented to the requirement of downlink transmission on MIMO millimeter waves.It uses DP-QPSK to modulate the dual-channel phase-orthogonal signals in the same polarization and the local oscillator in the other orthogonal polarization.Channel separation,channel selection,and up-conversion with double frequency multiplication of the local oscillator are achieved by tuning polarization devices to introduce a phase shift between the signals and the local oscillator.Simulation shows that two 2.5 Gbps 16 QAM signals are up-converted to 25.5 GHz and 27 GHz respectively in the scheme,with EVMs of 3.08% and 3.09%,while channel isolation is about32 d B.The scheme has a simple structure and is feasible for system-level on-chip integration.A four-channel spectral-efficient up-conversion MIMO millimeter-wave signal transmission scheme is studied.This scheme is oriented to the requirements of the large-capacity downlink of MIMO millimeter-wave transmission.A Dual-Drive DP-BPSK modulator is adopted to modulate two orthogonal signals in both X and Y polarization states respectively,and connected in parallel with a Single-Drive PDM-MZM modulator that modulates the local oscillator.The optical delay line completes channel separation and channel selection,and finally realizes four-channel frequency conversion millimeter wave signal transmission.The simulation shows that four 2.5 Gbps 16 QAM signals are transmitted and up-converted to 25 GHz,25.5 GHz,26 GHz and 26.5 GHz respectively,while the EVM is 3.37%,4.61%,3.23%,and 4.64% respectively,and channel isolation is about 27.3 d B.The optical link parts of the scheme can be integrated.A high and low frequency mixed receiving scheme based on direct and heterodyne coherent detection is studied.This solution is oriented to the requirements of high and low-frequency mixed transmission in the uplink.Down-conversion technology and direct detection technology are used to receive millimeter waves,and heterodyne coherent detection is used to receive sub6 G signals.Coherent detection is adopted to ensure coverage because of its advantages of large dynamic range and long wireless transmission distance in sub6 G,while direct detection is adopted to ensure enhanced millimeter-wave coverage in hot-spot areas because of its advantages of simple structure and easy deployment.Simulation shows that a 25 GHz 16 QAM millimeter wave signal and a 3.5 GHz 16 QAM low-frequency signal are received respectively in the scheme,with EVMs of 4.35% and 3.33%.The optical link parts of the scheme support photonics integration.