Research

Current Research Interests

• Digital Twin of EM Environments

• Radio Propagation, Measurements, and Channel Modeling

• mmWave and THz Communications

• High-Speed Railway Communications, LTE-Railways, GSM-Railways, 5G-Railways

• 5G Massive MIMO and High Frequency Communication Techniques

• Big Data, Artificial Intelligence, and Cloud Computing in Wireless Communications

Expertise

• Deep understanding of propagation and channel

• Mature ray-tracing simulators flexible for various wireless communications in different realistic scenarios with various MIMO or massive MIMO arrays

• Rich experience in channel measurement, simulation, and modeling  

Core Competence -- High-Performance Ray-Tracing

Research group and platform website: http://raytracer.cloud

Features

•Various scenarios: different types, static and dynamic scenarios with customized mobility patterns

•Large frequency range: from sub 6 GHz to 400 GHz

•Complete propagation mechanisms: LOS, transmitted, reflection, scattering, and diffraction models with calibrated parameters

•MIMO and massive MIMO antenna arrays: with specified beamforming technologies

Platform components

•Ray-tracing engine + Scenario library + Material library + Antenna library

•Computing device: high-performance cloud computing platform of BJTU

Simulation outputs

Parameters are recorded for each ray, including: Types (Directed, reflected, scattered, diffracted), Reflection order, Time of arrival, Distance, Field intensity, Path loss, AoD and AoA azimuth, AoD and AoA elevation

Libraries and tools

• Scenario Library —— Railway scenarios, Urban city indoor and outdoor scenarios, Close-proximity communication scenarios

• Material Library

   Ray tracing simulation is site-specific, and material information of objects is required. BJTU has already conducted measurements for some typical materials at mmWave frequencies. By combining with ITU’s reference data at sub-100 GHz, we can construct the material database for RT simulation.

• Antenna Library

    Currently, CloudRT features an antenna library with a comprehensive set of antenna patterns, which all users are free to utilize. Users can achieve MIMO beamforming and pattern display through the antenna array beamforming tool and the pattern display tool.

• Antenna Array Beamforming Tool

     Features:

     Support various input files: json/phitheta/ffs.

     Arbitrary array beamforming in XY plane:  arbitrary array size/element spacing/element rotation.

     Adjustable rotation angle and excitation.

• Pattern Display Tool

    Features:

    Four different plot types: 3D/2D/Cartesian/Polar Plot.

    Support various input files: json/phitheta/ffs.

    Pattern analysis for key properties: Beamwidth/Side lobe level/Directivity etc.

 Ray-tracing calibration methodologies

• Calibrating the ray-tracing simulator in one scenario (at certain frequencies with certain materials) is necessary to ensure the accuracy of the simulations in similar scenarios.

• A similar scenario means that the scenario is composed of similar materials at similar frequencies, but with different geometrical dimensions and distributions of various objects.

Two calibration methodologies

• Propagation mechanism measurement and key parameter estimation for material

• Channel measurement and EM and geometrical parameters calibration for scenario:

    Some typical measurement data (SNR, received power, CIRs) and the 3D environment model are required as the input for the calibration.

    Either simulation annealing or multiple parameter estimation algorithms (i.e., SAGE) can be used for calibration of both EM and geometrical parameters of the scenario.

Milestones

• First link-level software demo of 5G communications for high-speed railway

• The hybrid channel modeling approach, partially technically supported by us, has been accepted in ITU-R WP 5D for IMT-2020 technology evaluation

• Successful MHN-E hardware prototyping based on the realistic channel generated by a ray-tracing platform

• The MHN-E will be deployed on the high-speed railway in the PyeongChang 2018 Winter Games Olympics

• Channel model standardization for IEEE 802.15 IG HRRC

• D.P. He, K. Guan, B. Ai, Z.D. Zhong, A. Kasamatsu, H. Ogawa, I. Hosako, and M. Yaita, “Kiosk Channel Modeling”, DCN: IEEE802.15-16-00-003d_Kiosk_Channel_Modeling, IEEE 802.15 Interim Meeting, Macau, Mar. 2016, was accepted by IEEE 802.15 TG3d “Channel Modelling Document (CMD)”, becoming the first standard channel model for THz communications

• The lighthouse project for smart rail mobility, “Characterization and Modeling for the Millimeter and Sub-Millimeter Wave MIMO Mobile Ultra-Broadband Channel enabling Smart Rail Mobility,” was jointly launched in 2016

What We are Doing

• Extensive simulations and comprehensive analysis of mmWave and THz channels based on the flexible ray-tracing simulator

• Efforts on a smart ray-tracing simulator enabling 5G/B5G, 5G-R, Rail 4.0, and 6G 

Things are Coming

• Simulations and measurements for high data rate communications enabling “smart future”, such as smart railway, smart factory, and so on 

• mmWave and THz channel models towards IEEE, 3GPP, and ITU-R standards 

Future work

• High-performance cloud ray-tracing simulation center enabling a smart future

• Smart environment reconstruction – multi-layer propagation environment texture reconstruction 

• Link level and system level simulation platform for proof of concept for 5G/B5G, 5G-R, Rail 4.0, and 6G