Improvement of FBMC over OFDM System in terms of PSD and BER

Abstract

Multicarrier modulation techniques are widely used for transmission as it is used to generate a signal waveform which gives spectral efficiency and is adaptable to the present conditions in the world. There are several waveforms of multicarrier modulations, some of the more widely known schemes are OFDM and FBMC.OFDM offers several advantages like orthogonality and low complexity at the transmitter and receiver by replacing number of modulators or demodulators. The major challenge in frequency selective channel is Inter Block Interference (IBI) which can be reduced by cyclic prefix OFDM (CP-OFDM).Although OFDM offers several advantages, it can be regarded that OFDM calls for facing challenges when it has to be applied on complex technologies. For example, the use of Orthogonal Frequency Division Multiple Accesses (OFDMA) needs to be synchronized at the input base station. This synchronization turned out practically difficult to build mobile environments where the affects due to Doppler shifts of various users are difficult to track leading to Inter Carrier Interference (ICI).  Further, the filters which are associated with the OFDM carrier have relatively large sidebands which results in Out Of Band radiations (OOB). All the challenges that are associated with the use of OFDM or Cyclic-prefix OFDM can be overcome by a new system namely Filter Bank Multi Carrier (FBMC) which is basically a form of Multi carrier modulation. Filter Bank Multi carrier system can rather be considered as an evolved version of cyclic-prefix OFDM. Unlike OFDM which filters the whole band, FBMC filters each and every subcarrier individually. In this paper, the challenges occurred due to OFDM have been addressed and a contrast is drawn proving that the filter bank multi carrier could be more effective solution to be employed in various networks. A comparison has been drawn between FBMC and OFDM based on their power spectral densities, PAPR, BERversus SNR comparison using mat lab.