Modified Raised Cosine Power Pulse (MRCP) Based Solution to Reduce the Sensitivity to Carrier Frequency Offset in Rayleigh Faded OFDM System

摘要

Orthogonal Frequency Division Multiplexing (OFDM) is a digital multicarrier modulation technique used to eliminate Inter Symbol Interference (ISI) for high rate transmission over time dispersive multipath fading channels. Carrier frequency offset caused by the mismatch in oscillatorfrequency at the transmitter and receiver lead to the loss of subcarrier orthogonality, resulting in Inter-carrier Interference (ICI) amongst the subcarriers, reduction in Signal to Interference ratio (SIR) and increase in error floor of the system. This paper examines the effects of carrierfrequency offset on the ICI and SIR and proposes a Modified Raised Cosine Power (MRCP) pulse shape based solution to overcome the problems of carrier frequency offset. The simulation results show that MRCP pulse shape outperforms Improved Sinc power (ISP) pulse and Raised Cosine (RC) pulsein terms of ICI power reduction, SIR and BER performance. Therefore MRCP pulse shape based OFDM system suffers much less from performance degradation caused by frequency offset than the normal OFDM system.