Waveform design and nonlinear sensitivity analysis of WR-OCDM system for B5G wireless communications

In the future, the wireless communication network’s data handling capability will be exhausted due to various type of Internet of Things (IoT) devices being incorporated and extensive data rate, and these networks will be unable to meet the traffic demand, so it is necessary to think about the improvement of bandwidth efficiency. The radio interface’s efficiency is massively optimized when the signaling overhead is reduced and coarse synchronization is included. From this stem, this is expected to have a considerable negative impact on the waveform orthogonality of existing systems and result in annoying intercarrier interference (ICI). To improve spectral efficiency, spread spectrum technology known as orthogonal chirp division multiplexing (OCDM) considers the orthogonality of cyclically shifted quadratic chirp signals. In this research article, an effective WR-OCDM system has been suggested, designed over an AWGN channel across a 40 MHz frequency band to enhance the complexity of spectral efficiency and incorporate beyond 5G (B5G) or future-generation wireless communication systems. Where discrete Fresnel Transform (DFnT), and windowing techniques have been implemented to improve the physical layer security of our proposed system. The employment of the windowing technique significantly reduced the system’s out-of-band (OOB) power emission and achieved spectral mask compliance with a short window length. With a window length of up to 30 (less than half of the cyclic prefix (CP)), the proposed WR-OCDM system substantially reduces OOB power emissions like universal filtered multicarrier (UFMC) and filter bank multicarrier (FBMC) systems. Compared to conventional OFDM and OCDM systems, simulation results verify that the proposed WR-OCDM reduces OOB power emissions by 35 dB and 67 dB for window lengths 4 and 30, respectively, without compromising communication quality. Finally, we evaluate the performance of the bit error rate (BER) in HPA nonlinear conditions, emphasizing its robustness and practicality for real-world implementation.