Dynamic Optimization of Overlap-and-Add Length Over MBOFDM System Based on SNR and CIR Estimate

Abstract

An important role performed by Zero Padding (ZP) in multi-band OFDM (MB-OFDM) System. This role show for low-complexity in résistance against multipath interference by reducing inter-carrier interference (ICI) and eliminating the inter-symbol interference (ISI) Also, zeropadded suffix can be used to eliminate ripples in the power spectral density in order to conform to FCC requirements. At the receiver of MB-OFDM system needs to use of a technique called as overlap-and-add (OLA). Which maintain the circular convolution property and take the multipath energy of the channel. In this paper, we proposed a method of performing overlap-and-add length for zero padded suffixes. Then, we studied the effect of this method, dynamic optimization of overlap-and-add (OLA) equalization, on the performance of MBOFDM system on Bit Error Rate (BER) with AWGN channel and Saleh-Valenzuela (S-V) Multipath channel Model. In the dynamic optimization OLA, the Length of ZP depends on length of channel impulse response (CIR). These measures, based on SNR, insert the ZP according to the measurement. Dynamic optimization of length of ZP improves the Performance of MBOFDM system. In fact we developed a technique to select the length of ZP as function of SNR and CIR estimate(repetition). In our simulation this technique improve to 3 dB at BER=10-2 with a multipath channels CM4.