Performance Improvement of Generalized Frequency Division Multiplexing based 5G Communication System

Abstract

The current fifth generation (5G) technology has brought a paradigm shift in wireless communication systems, offering unprecedented speeds, ultra-low latency, massive device connectivity, and remarkable network capacity. While 5G is still in its early stages of deployment and expansion, researchers and industry experts are already contemplating the requirements, challenges, and opportunities for ”beyond 5G” (B5G) communication. The development of B5G is gaining attention as the global community seeks to redefine wireless communication systems for the future. The diverse requirements of the B5G standards include data rates of 1 Gb/s, device density of up to 107 devices/km2, high mobility of up to 1000 km/h, and latency in the range of 10−100 μs. To cater for the evolving requirements of future communication systems many current and future standards have adopted multicarrier techniques which include both orthogonal (i.e., Orthogonal Frequency Division Multiplexing (OFDM) and Universal Filtered Multicarrier (UFMC) and non-orthogonal (i.e., Generalized Frequency Division Multiplexing (GFDM), Orthogonal Time Frequency Space (OTFS), and Filter Bank Multicarrier (FBMC) techniques. GFDM has gained attention as a non-orthogonal waveform with several advantageous features, making it a viable choice for future generations (like B5G, 6G). These advantages include its flexible structure, resilience against frequency selective fading, minimal OOB emissions, high spectral efficiency attributed to reduced CP overhead, and low PAPR. This dissertation aims to enhance the performance of GFDM-based 5G communication systems. It includes a performance analysis of the GFDM system over mmWave channels, particularly the FTR channel. The impact of channel impairments, such as the unavailability of perfect channel state information (CSI), on the performance of GFDM systems is also presented. The second contribution of this thesis is the introduction of a novel timing synchronization algorithm, which significantly improves the performance of GFDM systems. This improvement leads to increased reliability in data transmission, a crucial aspect of the B5G system. The third contribution involves a novel filter design method based on the discrete biorthogonality condition and Wigner Distribution (WD). The proposed filter enhances the GFDM system’s performance in terms of both Symbol Error Rate (SER) and Power Spectral Density (PSD). The analytical results derived from the proposed expressions are verified through Monte Carlo simulations. In some cases, numerical integration is required over finite limits, which can be easily implemented with negligible error using tools such as MATLAB and Mathematica.