DEVELOPMENT OF A RAMP-BASED PULSE SHAPING FILTER FOR REDUCING OUT OF BAND EMISSION IN GFDM SYSTEM

Abstract

Due to ever increasing demand of services in the eld of mobile communication, the fourth generation based systems have reached a saturation stage. The world today is looking towards a new Radio Access Technology (RAT) in the face of fth generation, which would open doors for a variety of new services. The three main use cases envisioned for 5G network are enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC) and Ultra Reliable and Low Latency Communication (URLLC). This dissertation discusses about the URLLC use case which will transmogrify the applications such as mobility and tra c, health monitoring, augmented reality, education, etc. These scenarios are referred to as Tactile Internet, as such low latency is needed in tactile steering and keeping a check on real time operations such as virtual gaming. This thesis presents Generalized Frequency Division Multiplexing (GFDM) as potential candidate for forming the PHYsical (PHY) layer of the next generation RAT due to its appealing properties such as low out of band (OOB) radiation and optimal use of time-frequency resources. In this thesis, frequency domain implementation of GFDM transmitter is studied and closed form of solutions for the Power Spectral Density (PSD) and Symbol Error Rate (SER) are presented. Various lters such as root raised cosine (RRC), Xia Pulses, etc. are proposed in the literature for pulse shaping of GFDM waveform. These lters a ect the amount of OOB radiations and SER performance of the system in di erent ways. There is always a trade-o between the two performance indices, specially in low latency scenarios. Thus, it is important to design a lter impulse response which can provide an optimal solution so as to get the best out of the GFDM system. This dissertation proposes a novel ramp-based nite impulse response (FIR) lter for pulse shaping the GFDM waveform in the frame structure of tactile internet. The proposed lter makes an e ort to address the limitation of the RRC and Xia lters. For the three lters, the PSD is calculated with respect to di erent sub-carriers. The SER v/s signal to noise ratio (SNR) performance is tested in various channel models such as additive white gaussian noise (AWGN), extended vehicular A (EVA) and extended typical urban (ETU). Simulation results show that a system with proposed ramp-based lter o ers signi cantly low OOB radiation as compared to RRC lter and Xia Pulse. Furthermore, the SER performance of the proposed ramp-based lter is superior to Xia pulse in di erent channel models