Effects of Filtering on Ber Performance of an Ofdm System

Abstract

Index Terms: AWGN, ICI, OFDM, Bit E ----------------------------------------------------------------------- INTRODUCTIONHigh bit error rate(BER) and high bandwidth efficiency the major desiresfor modern communication sy the needs for a variety of new and high quality services developed and delivered to the society [1]. The effect of multipath delay, spread and fading of signals in the wireless environment is usually unavoidable [2], [3]. Extreme fading of the signal amplitude and Inter Symbol Int introduced during transmission through t channel and frequency selectivity of the channel appearing at the receiver side [4], [5] are responsible for a high probability of errors and reduced overall performance of the system. Several methods like adaptive equalization and channel coding have been developed to reduce the above effect.[6], [7]. The orthogonal Frequency division multiplexing (OFDM) a multi carrier system can be thought of as a solution and is used in several applications such as asymmetric digital subscriber lines (ADSL), a system that makes high bit-rates possible over twisted-pair copper wires [8], [9], it has also been accepted for several wireless LAN standards, as well as a number of mobile multimedia applications [1], [10] and protocols like IEEE 802.11a standard, terrestrial digital video broadcasting (DVB T) and digital audio broadcasting (DAB) [11]. The purpose of this paper is to investigate how OFDM performs in an Additive White Gaussian Noise (AWGN) ch pulse shaping filter like Raised cosine, FIR Nyquist and Matched SQRT Raised Cosine. In this channel one path between transmitter and receiver and attenuation and noise is considered. In this paper, we define the simulation methodology of OFDM in section 2 and simulate the OFDM system using Matlab. The mathematical model and theoretically simulated constellation diagrams for various pulse shapes are presented and a procedure for symbol IJRET: International Journal of Research in Engineering and