Enabling Wireless Communications in the Terahertz Band

Project Description

Ultra-Massive MIMO

The concept of UM-MIMO is based on the use of very large antenna arrays with thousands of antenna elements. As for lower frequency communication systems, very large antenna arrays can be utilized to increase the communication distance by means of beamforming, i.e., reducing the spreading loss by focusing the transmitted signal in space. For example, large arrays with tens to hundreds of antennas can be utilized to enable massive MIMO communications in mm-wave systems. When moving to the THz band, however, the significantly small wavelength allows the development of much larger antenna arrays. For example, if we limit the antenna array area to 5 mm x 5 mm, the total number of antenna elements could be increased up to 1024 at 1 THz. So far, we have proposed graphene to build novel plasmonic nano-antennas which are able to efficiently radiate at THz frequencies and filed a patent. We will continue with our studies on the fabrication of these nano-antennas and the design of plasmonic antenna array to realize the UM-MIMO.



Three-Dimensional (3D) Terahertz Band Channel Modeling

Existing THz-band channel models consider the EM wave traveling only in the horizontal plane, while the influence from the elevation plane is neglected. However, in realistic application scenarios, the multi-path rays reach the receiver from any direction, in both the azimuth and elevation planes. This is the result of both, the 3D radiation diagram of the antennas and the 3D propagation of the wave in the space. As a result, there is a need for a 3D end-to-end multi-path channel model, which includes the influences from both the antenna radiation pattern and the 3D EM wave propagation.



Advanced Communication Solutions

Fog computing extends the cloud-based Internet by introducing an intermediate fog layer between devices and cloud, aiming at providing the smooth, low-latency computing service to devices. Despite its great advantage, fog computing faces fundamental challenges when the things, e.g., wearable sensors, smart phones, and connected vehicles, become increasingly mobile. To counter this problem, first, it is highly desirable to intelligently connect the mobile thing to a new fog server in its vicinity, which has sufficient computing, memory and wireless bandwidth resources. Second, besides selecting optimal fog sever, connecting to a new server requires the efficient live virtual machine migration, which is a process of relocating the virtual machine of the mobile thing from its previous hosting fog server to the new one, with the minimum service disruption time.





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