Advanced Orthogonal Frequency-Division Multiplexing Systems with Cyclic Prefix-Less Multiple-Input and Multiple-Output Discrete Fourier Transform Spreading and Unmanned Aerial Vehicles-Assisted Cyclic Postfixed Windowed Schemes
Date
2023Metadata
[+] Show full item recordAbstract
In the proper designing of spectrally efficient 5th Generation (5G)/Beyond 5G (B5G) systems, minimization of Peak-to-Average Power Ratio (PAPR) of the time domain Orthogonal Frequency-Division Multiplexing (OFDM)/Cyclic Prefix (CP)-less OFDM signal and reduction of baseband signal Out-of-Band (OOB) spectral power in the vicinity of boundaries of the transmission frequency band is very much essential. In the perspective of considering the non-compatibility of CP-less Single-Input Single-Output (SISO) OFDM technique with Multiple-Input Multiple-Output (MIMO) technology adopted 5G systems, we present the first CP-less MIMO OFDM System. It is based on incorporating Discrete Fourier transform (DFT) spreading, signal discrimination with Walsh-Hadamard coding, and PAPR reduction with Tukey (tapered cosine) time-domain windowing techniques. This combination of mechanisms provides an effective combination of benefits related to Bit Error Rate (BER), PAPR, Complementary Cumulative Distribution Function (CCDF) of PAPR, and OOB spectral power. The BER performances of our system in its simplified (SISO) form are compared with the CP-less SISO OFDM system. Additionally, the estimated OOB powers are also compared with various future-generation wireless communication systems such as DFT-Spread Windowing and Restructuring Orthogonal Frequency Division Multiplexing (WR-OFDM), Universal Filtered Multi-Carrier (UFMC) and Filter Bank Multi-Carrier (FBMC). Our simulation study shows that the proposed scheme achieves OOB spectral power attenuation of 142 dB with PAPR of 8.56 dB and BER of 10⁻⁴ under a scenario of Signal-to-Noise Ratio (SNR), Eb/N₀ = 15 dB with 16-Quadrature Amplitude Modulation (16-QAM) modulation.
To improve the spectral efficiency and robustness of wireless communication systems, on the other hand, drone-assisted 5G and beyond 5G wireless communication networking capabilities require strong consideration of constrained transmission power, user equipment receiver sensitivity, coverage area, and severe mmWave path loss. We present a Non-terrestrial downlink wireless communication system using a Cyclic Postfixed Windowed Orthogonal Frequency Division Multiplexing (CPW-OFDM) signal format. We demonstrate the impact of combining a Tukey windowing technique with Clipping and Filtering (CF) techniques for the simultaneous reduction of both OOB energy and PAPR. Block Diagonalization (BD) channel precoding provides Multi- user Interference (MUI) reduction, while (3,2)- Single Parity Check (SPC), Repeat and Accumulate (RA) channel coding, and Zero Forcing (ZF) signal detection schemes improve BER. Numerical results confirm that the proposed Non- terrestrial downlink CPW-OFDM system is suitable for multi-user signaling on mmWave frequencies.
Table of Contents
Introduction -- Literature review -- Cyclic prefix-less MIMO Discrete Fourier Transform Spread OFDM system -- UAV-assisted multiuser non-terrestrial cyclic postfixed windowed OFDM system -- Conclusion and future work
Degree
Ph.D. (Doctor of Philosophy)