PERFORMANCE ANALYSIS OF ADVANCED INDEX MODULATION SYSTEMS FOR NEXT GENERATION WIRELESS COMMUNICATION SYSTEMS
Tez Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: İstanbul Medeniyet Üniversitesi, Lisansüstü Eğitim Enstitüsü, Elektrik-Elektronik Mühendisliği, Türkiye
Tez Danışmanı: Erdoğan Aydın
Tezin Onay Tarihi: 2022
Tezin Dili: Türkçe
Özet:
In wireless communication, individual and industrial demands on essential parameters such as faster and better quality data transmission, low-latency communication, high spectral efficiency, and low energy consumption continue to increase rapidly day by day. Therefore, communication systems aiming to meet these demands are becoming more important. The index modulation (IM) technique makes it possible to transmit data bits through indices of parameters that play a role in communication. IM-based communication systems provide high spectral efficiency, high energy efficiency, high data rate, and high error performance. However, existing IM-based systems are insufficient to meet the demands listed above, and new high-performance wireless communication systems are needed. In the first study in this thesis, a new high-performance wireless communication system called CIM-SMBM, which combines code index modulation (CIM), spatial modulation (SM), and media-based modulation (MBM) techniques, is proposed to provide high data rate, high spectral efficiency, high error performance, and low energy consumption. In the proposed CIM-SMBM system, data bits are carried in three indices and transmitted symbols. These three indices are; the active antenna index selected by the SM, the different channel state index that changes depending on the propagation pattern determined by the MBM, and the spreading code indices determined by the CIM. Three different detectors have been proposed for the CIM-SMBM system. First, the ML detector is proposed for the CIM-SMBM system. Afterward, to reduce the ML detector complexity, a despreading-based ML (DB-ML) detector which estimates the spreading code indices according to the despreading principle is proposed. Finally, to further reduce the complexity of the DB-ML detector, an enhanced low complexity (ELC) detector providing error performance close to the ML detector is proposed. Average bit error rate (ABER), throughput (TP), energy efficiency, and computational complexity analyzes of the proposed CIM-SMBM system are presented for M-ary quadrature amplitude modulation (M-QAM) and Rayleigh fading channels. Also, the results obtained for the CIM-SMBM system are compared with the important IM systems in the literature and it has been seen that the proposed CIM-SMBM system provides a higher data rate, higher energy efficiency, and better error performance than the compared systems. Reconfigurable intelligent surface (RIS) technology, which has become very popular recently and can reduce the disruptive fading effect of the wireless communication channel, has taken its place among the important communication systems. RIS technology increases the performance of the communication systems into which it is integrated. In this context, in the second study in this thesis, a new system called DSM-RIS, in which a double SM (double SM, DSM) system, which doubles the data rate of the traditional SM technique, and RIS technology is combined within a communication system is proposed. Performance analyzes of the proposed DSM-RIS system are obtained for M-QAM modulation on the Rayleigh fading channels. The data rate and performance analysis results of the proposed DSM-RIS system are compared with important counterpart systems such as RIS-based SM (SM-RIS), RIS-empowered media-based modulation (MBM-RIS), and quadrature SM-RIS (QSM-RIS). According to the results obtained, it has been seen that the proposed DSM-RIS system provides better error performance and higher spectral efficiency than the compared systems.