Let MultiBand-OFDM Modified By Wavelet

J Avila

doi:10.17485/ijst/2014/v7i8.8

Abstract

This paper throws light on elevating the performance of MB-OFDM by diverse techniques. The initiative was that the wavelet transform altered the place of FFT and IFFT. The use of the wavelet transform can be ascribed to the fact that it counteracts various types of interference. Implementation of various modulation techniques refines the performance. The order of the wavelet transforms used should remain conducive to establish it as an efficient system for high data rates. As an outcome of noise the output of the channel is erroneous. Hence error control codes are utilized which aims at the removal of error from the transmitted bits. Further to achieve diversity space time block codes are concatenated with FEC codes. Keywords: Fast Fourier Transform (FFT), Multiband OFDM, Neural Network, Space Time Block Code (STBC), Ultra Wide Band, Wavelet Transform

Highlights

The ultra wide band spectrum extending from 3.1GHz to 10.6 GHz faces difficulty in its handling owing to its wide spectral width[1].To circumvent the challenges multiband OFDM came into its application by virtue of its high data rates, less power consumption and need of less silicon space
Results are concluded from the Bit Error Rate (BER) versus Eb/N0 curve plotted for the multiband OFDM system
Binary Phase Shift Keying (BPSK) modulation scheme is preferred because it is less error prone when compared with other schemes

Summary

Introduction

The ultra wide band spectrum extending from 3.1GHz to 10.6 GHz faces difficulty in its handling owing to its wide spectral width[1].To circumvent the challenges multiband OFDM came into its application by virtue of its high data rates, less power consumption and need of less silicon space. Among the 128 available sub-carriers with sub-carrier spacing of 4.125MHz 100 is used for data transmission, 12 plays the role of the pilot carriers[3, 10] as guard tones and 6 as null tones. The input data sequence is taken randomly with the help of a scrambler followed by encoding the channel using an encoder[4]. The mapped output is sent through an IFFT block to convert into OFDM symbols by an OFDM modulator. The receiver implements the reverse operations such as demodulation and decoding to retrieve the original sequence[7]

Methods

Results

Conclusion