Design and Performance Evaluation of Nonorthogonal Multicarrier Transmission for Next Generation Wireless Networks

Abstract

Future wireless networks are expected to provide massive connectivity, ultra-high data rates, and ultra-reliable low-latency communication (URLLC). Achieving these desired features at the physical layer requires advanced and efficient multiple-access techniques, robust signal design, and multi-layer diversity. This dissertation aims to propose advanced and efficient non-orthogonal multicarrier transmission schemes with time, frequency, and space diversity to support the ultra-reliable communication requirements of next-generation wireless networks. The hybrid use of non-orthogonal multiple access (NOMA) with orthogonal frequency division multiplexing (OFDM) is a promising multiple access technique for future-generation wireless networks. NOMA-OFDM with advanced diversity techniques is proposed to improve spectral efficiency in frequency-selective wireless channels.

The first part of this dissertation deals with the design and performance analysis of OFDM-multiple-input multiple-output (MIMO) systems with time-domain interleaving (TDI). Specifically, the bit error rate (BER) and outage probability (OP) performance analysis of OFDMMIMO systems with TDI using zero-forcing (ZF) and minimum mean squared error (MMSE) equalizers over Rayleigh fading multipath channels are investigated. The proposed system’s instantaneous signal-to-noise ratio (SNR) and signal-to-interference-plus-noise ratio (SINR) are derived and used to evaluate the BER and OP semi-analytically for various modulation schemes and receiving antenna configurations. The analytical and Monte Carlo simulation results show that the proposed OFDM-TDI with space diversity provides significant BER and OP performance gains over the conventional OFDM.

The second part of this dissertation investigates the performance of OFDM-based NOMA-single-input single-output (SISO) with TDI over Rayleigh fading multipath channels focusing on enhancing reliability, reducing error rates, and improving outage performance. The instantaneous SINR is derived using an MMSE equalizer considering two and three downlink users, which is used to derive analytical expressions for the BER and OP. The theoretical and simulation results show that TDI enables significant SNR gains and reduction in BER and OP for both near and far users compared to the conventional NOMA-OFDM without TDI.

The final part of the dissertation focuses on the performance analysis of OFDM-based NOMA-MIMO with TDI using ZF and MMSE equalizers. In particular, semi-analytical BER and OP expressions are derived, and the theoretical and simulation results confirm that TDI combined with multiple antenna systems leverages spatial diversity to achieve further BER and OP performance gains demonstrating the robustness of the proposed approach in multipath fading channels. These findings highlight the effectiveness of TDI in improving the performance of NOMA-OFDM with space diversity, making it a promising solution for future wireless networks that demand ultra-reliable communication under adverse channel conditions.

Date of Award	22 May 2025
Original language	American English
Supervisor	Arafat Aldweik (Supervisor)