Characterization of GFDM Signal with Timing Offset, CFO, Non-Linearity, and PN

In this paper, we study the joint effects of timing offset (TO), carrier frequency offset (CFO), nonlinear power amplifier distortion, and phase noise (PN) on generalized frequency division multiplexing (GFDM) system. Closed form expressions for signal-to-interference ratio (SIR) at GFDM receiver with synchronization errors and PN using a nonlinear power amplifier is derived. Then, we have been conducted simulation studies to compare the performance of GFDM systems with orthogonal frequency division multiplexing (OFDM) systems using matched filter (MF) and zero forcing (ZF), in presence of these impairments. The results show that GFDM systems are more robust against TO and PN while they are more sensitive to CFO and nonlinear distortion compared to OFDM systems.

CLIPPING TECHNIQUES FOR PAPR REDUCTION IN FBMC/OQAM SYSTEM OVER DOUBLY-SELECTIVE CHANNELS

One of the major disadvantages of Filter Bank Multicarrier (FBMC) is high Peak-to-Average Power Ratio (PAPR) of transmitted signal. As a result, nonlinear power amplifier (PA) properties, considerable out-of-band and the in-band distortion types take place in the case where the signals of high peak exceed the PA saturation level. In the present study, a new method of the PAPR reduction is presented and applied to reduce PAPR in FBMC/OQAM system. Different clipping methods have been proposed and studied that are Amplitude Clipping (AC), Palm Clipping (PC), Deep Clipping (DC), and smooth Clipping (SC) for the reduction of PAPR. To evaluate and analyze the performance of PAPR reduction methods, PAPR and Bit Error Rate (BER) measures are used and programmed using MATLAB program. The simulation results show that the clipping methods are strong substitute methods which may be assumed as a method of PAPR reduction for the FBMC-based communication systems and AC appears to be the best method.

Linear and Non-Linear Companding Transformation Reducing PAPR in OFDM Signals

An important disadvantage of Orthogonal Frequency Division Multiplexing (OFDM) signals is high peakto-average power ratio (PAPR), causing genuine debasement popular execution when a nonlinear power amplifier (PA) is utilized. A notable technique to diminish power ratio deprived of confinements on framework parameters is Companding Transform (CT), for example, the sum of subcarriers, outline organization, and gathering type. Another nonlinear companding change, the utilization of hyperbolic transfer sigmoid function capacity is proposed for PAPR decrease in this paper. The proposed methodology extends the little flag and packs the pinnacle flag in the time zone at the same time without changing the average power. Results dependent on MATLAB demonstrate that the proposed methodology increases additional pinnacle decrease and improves the BER (bit error ratio)execution.