abstract: The demand for the higher data rate in the wireless telecommunication is increasing rapidly. Providing higher data rate in cellular telecommunication systems is limited because of the limited physical resources such as telecommunication frequency channels. Besides, interference with the other users and self-interference signal in the receiver are the other challenges in increasing the bandwidth of the wireless telecommunication system. Full duplex wireless communication transmits and receives at the same time and the same frequency which was assumed impossible in the conventional wireless communication systems. Full duplex wireless communication, compared to the conventional wireless communication, doubles the channel efficiency and bandwidth. In addition, full duplex wireless communication system simplifies the reusing of the radio resources in small cells to eliminate the backhaul problem and simplifies the management of the spectrum. Finally, the full duplex telecommunication system reduces the costs of future wireless communication systems. The main challenge in the full duplex wireless is the self-interference signal at the receiver which is very large compared to the receiver noise floor and it degrades the receiver performance significantly. In this dissertation, different techniques for the antenna interface and self-interference cancellation are proposed for the wireless full duplex transceiver. These techniques are designed and implemented on CMOS technology. The measurement results show that the full duplex wireless is possible for the short range and cellular wireless communication systems. / Dissertation/Thesis / Doctoral Dissertation Engineering 2017

This dissertation is aimed at examining signal integrity degradation factors and realizing signal integrity enhancement circuits for both wired and wireless communication systems. For wired communication systems, an optical coherent system employing an electrical equalization circuit is studied as a way of extending the transmission distance limited by optical fiber dispersion mechanisms. System simulation of the optical coherent receiver combined with the feed-forward equalizers is performed to determine the design specification of the equalizer circuit. The equalization circuit is designed and implemented in a 0.18 µm complementary metal-oxide semiconductor (CMOS) process and demonstrates the capability to extend the transmission reach of long-haul optical systems over single-mode fiber to 600 km. Additionally, for wireless applications, signal integrity issues found in a full-duplex wireless communication network are examined. Full-duplex wireless systems are subject to interference from their own transmitter leakage signals; thus, a transmitter leakage cancellation circuit is designed and implemented in a 0.18 µm CMOS technology. The proposed cancellation circuit is integrated with a low-noise amplifier and demonstrates over 20 dB of transmitter leakage signal suppression.

Frequency Modulated Continuous Wave (FMCW) radar has wide application areas in both civil and military use. The range resolution is a critical concept for these FMCW radars as for the other radar types. There are theoretical restrictions in the range resolution. In addition, the non-ideal properties of the modules used in the systems negatively affects the range resolution. The transmitter leakage, non-linear frequency sweep, FM to AM distortion and measurement errors are some of the critical non-ideal properties. The problems arising from these non-ideal properties further restrict the range resolution of FMCW radars. Another important concept for the range resolution that can be obtained from FMCW radars is the signal processing method. This thesis deals with the non-ideal properties of the system modules and techniques to reduce their effects on the range resolution. Furthermore, the signal processing methods used for FMCW radar signals and the possible improvement techniques for these methods are discussed. Moreover, a simple signal processing unit called zero crossing counter which can be used for short range FMCW radars is implemented and range resolution performance of this zero crossing counter is investigated by carrying out measurements on a prototype FMCW radar at 2200MHz.