TRANSFORMATION OF THE WALSH HADAMARD PILOT SYMBOL TO AN EFFICIENT OPTIMAL PILOT SYMBOL

Abstract

The OFDM is a modulation method vulnerable to non-linearities of source, channel or amplifier due to its high peak
average ratio (PAPR). The distortion is exacerbated by the increase in the average OFDM signal strength, as more
signals are impacted by non-linearity. In this article, we present Hadamard coded modulation (HCM), which
employs the fast Walsh-Hadamard transform (FWHT) to modulate information in wireless optical systems as an
alternative to OFDM. Due to its small PAPR this technique is shown to be better for high-medium optical power
scenarios and can be used in two scenarios instead of OFDM: 1) in optical systems requiring higher optical power
such as visible light communications, and 2) in wireless optical systems with lower mean power (BER)
uncomplicated by average power. The power effectiveness of HCM can be increased without sacrificing information
by eliminating some of the DC bias of the signal. This reduces the amplitude of the transmission signal and reduces
the non-linearity of the signals. HCM can be connected to resist interlocking symbolic (ISI) effects via evenly
spreading the interference to all symbols on dispersive channels. In section 1 we discuss about introduction, Section
2 tells about related work we build our proposed system using this related work. In section 3 we explain about
proposed system, Section 4 tells about results what we got and final section 5 conclusion about our work.