Electronic Thesis and Dissertation Repository


Doctor of Philosophy


Electrical and Computer Engineering


Rao, Raveendra

2nd Supervisor

Al-Dweik, Arafat



During the last decade, major evolutions were introduced for Multiple Input Multiple Output (MIMO) wireless communication systems. To reap the full benefits of MIMO systems, the Base Station (BS) and user equipments require accurate Channel State Information (CSI), which can be acquired using one of the two major approaches for Channel Estimation (CE): pilot-based or blind-based CE.

In this thesis, a pilot-based lower complexity channel estimator for Cell-Specific Reference Signals (C-RS) and User Equipment RS (UE-RS) in LTE-A Downlink (DL) system is proposed based on using a hybrid Wiener filter. The proposed system is a sub-optimum scheme that requires 8.8% and 74.5% of the number of computations required by the optimum system and other sub-optimum systems. Moreover, a less computationally complex CE scheme based on Fast Fourier Transform (FFT) is proposed. The presented pilot-based system is validated in end-to-end LTE-A system in terms of throughput, which confirms that the proposed system is suitable for practical implementation. Next, a new blind-based CE technique based on a hybrid OFDM symbol structure for SIMO and MIMO systems is presented. It is shown that the developed system, with enough receive antennas, performs as good as pilot-based system, with similar complexity and better spectral efficiency. Finally, new Resource Grid (RG) configurations that serve the blind-based CE scheme developed for MIMO-OFDM system are presented, with the aim to improve the Mean Squared Error (MSE) performance, while minimizing the number of required receive antennas. Results show that the proposed RG configurations provide superior MSE performance, from the perspective of the blind-based CE scheme under investigation, compared to the LTE-A RG configuration.

Throughout the thesis, performances of linear receivers is presented in terms of spectral efficiency as a function of Signal-to-Noise Ratio (SNR), and number of BS antennas. CE techniques are evaluated in terms of MSE as a function of SNR for different channel condi- tions. Analytical results wherever possible and, in general, simulation results are presented.

Available for download on Wednesday, April 22, 2020