Research Information System
Thesis Type: Doctorate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2023
Thesis Language: Turkish
Student: Bircan Demiral
Supervisor: Özgür Ertuğ
Open Archive Collection: AVESIS Open Access Collection
Abstract:
Today, the need for technologies that provide more perform to users has led to the establishment of complex communication systems. Due to increasingly complex communication scenarios and network architectures and increasing data traffic demands, current orthogonal multiple access (OMA) techniques have fallen short of guaranteeing main net requirements in terms of spectrum efficiency, user fairness, reduced latency, better connectivity, data rate and energy efficiency in next generation 5G networks. Non orthogonal multiple access (NOMA) technique has been proposed to overcome various challenges in 5G wireless systems and over time traditional OMA techniques have evolved into NOMA techniques. Among the NOMA techniques, the most remarkable techniques are the power-domain non-orthogonal multiple access (PD-NOMA) and sparse code multiple access (SCMA) techniques. PD-NOMA sends data with the superposition method to provide spectral efficiency after allocating power to the users according to the channel conditions, and uses the successive interference cancellation (SIC) method at the receiver to reduce the interference. Multi input multi output (MIMO) systems providing high efficiency and reliability are combined with PD-NOMA. However, with the use of more than one antenna, radio frequency (RF) chains also increase, resulting in higher costs, complexity and power consumption than expected. Based on these reasons, firstly, max-max-max and max-min max antenna selection algorithms that aim to increase the data rate while reducing the number of antennas for downlink MIMO PD-NOMA are applied in the thesis. Then, the SCMA technique, which supports user interference and overloading thanks to the sparse structure, is integrated with MIMO. Since there is clarity about antenna selection in MIMO SCMA systems in the literature, these antenna selection algorithms have been developed for more users and in addition, the optimum antenna selection algorithm has been applied to this downlink system. As a result of the applications, the capacity, bit error rate (BER) and outage probability provided by the algorithms to the systems were simulated in the Matlab/Simulink program and shared.
Key Words : Power domain non-orthogonal multiple access, sparse code multiple
access, multi input multi output, antenna selection, radio frequency
chain, capacity, bit error rate, outage probability