Electrical and Electronics Engineering MS Thesis Defense by Nabil Khalid







Title: Physical Layer Design of Terahertz Band 5G Wireless Communications


Speaker: Nabil Khalid


Time: August 10, 2017, 13:00 – 15:00


Place: ENG 127

Koç University

Rumeli Feneri Yolu

Sariyer, Istanbul

Thesis Committee Members:

Dr. Ozgur Baris Akan (Advisor, Koc University)

Dr. Sinem Coleri Ergen (Koc University)

Dr. Fatih Alagoz (Bogazici University)


The emerging technology Terahertz Band (0.3 – 10 THz) communication is envisioned to accommodate high speed wireless communication. Large bandwidth makes it a good candidate for 5G mobile networks as it can alleviate the problem for spectrum congestion. In this thesis, we propose the first ever physical layer design of communication in THz Band not only for single-input single-output (SISO) based networks but also multiple-input multiple-output (MIMO). We first introduce the testbed system and present its use for carrying fundamental experiments in THz Band. Path loss and phase delay measurements from 260 GHz to 400 GHz for different distances, angles of arrival and objects acting as reflectors are then discussed. We have shown links reaching speeds of terabits per second that confirms THz Band as an excellent candidate for 5G wireless networks. Furthermore, we statistically analyze the THz Band channel and determine the exponent of a path loss exponent model with log-normal shadowing. Channel coherence bandwidth is also determined using the power delay profile information. We also analyze different modulation schemes based on there energy consumption, data speed and bit-error rate. The analysis helps us determine the most energy-efficient modulation scheme for THz Band, which is very important as energy-consumption is a challenging problem for high speed wireless data transmission. Moreover, we propose a THz Band transceiver design that can be used for network demonstration and can be extended for protocol testing. Furthermore, we present the first ever experimental results of a THz Band line-of-sight (LOS) 2 x 2 MIMO channel using the principles of diffraction limited optics. Finally, we look at a some networking scenarios in full-dimension multiple-input multiple-output (FD-MIMO) based THz Band indoor wireless networks to determine the number of nodes that can be connected to a base station as a function of the antenna characteristics.