Abstract: Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier modulation technique in which the subcarriers are orthogonal to each other. OFDM provides high data rate, resistance to multipath fading. OFDM provides an effective and low complexity means of eliminating inter symbol interference for transmission over frequency selective fading channels. OFDM is becoming widely applied in wireless communications systems like digital audio broadcasting (DAB) systems, digital video broadcasting (DVB) systems, digital subscriber line (DSL) standards, and wireless LAN standards. Signal to noise ratio is used as an indicator for evaluating the quality of communication. So it is very important to estimate the SNR value for the modern wireless communication. By introducing a specific pilot sequence built from ZC sequences, pilot can be used as synchronizing mechanism in time domain as well as channel estimation. In this paper OFDM Systems with Zadoff-Chu pilots is proposed. Also Selected Level Mapping (SLM) and Clipping and Filtering techniques have been used for Peak-to-Average Power Ratio (PAPR) reduction, since high PAPR of the transmit signal is considered to be one major drawback of OFDM systems. The proposed system can be used for providing better performance of the communication systems.

Keywords: OFDM, Zadoff-Chu, PAPR, SLM, Clipping and Filtering.