Performance Comparision of ICI in OFDM Using Kaiser Hamming and Hann Window Functions

In Orthogonal Frequency Division Multiplexing (OFDM) carriers are orthogonally related and hence no guard band is necessary like in Frequency Division Multiplexing (FDM). So spectrums of users can overlap which enhances the spectrum efficiency of the network. In this thesis one of the main concern of OFDM, inter carrier interference (ICI) is considered using different window functions in frequency domain in pulse shaping of OFDM data symbols which are considered uncorrelated. It reduces the inter carrier interference (ICI) power into simply the square magnitude of window function. Here we have taken different window functions for comparing performance of the wireless links in content of ICI power and desired received signal. Orthogonal Frequency Division Multiplexing (OFDM) is technique of multi-carrier modulation in which a single high rate datastream is first divided into multiple low rate data-streams and is then modulated using sub-carriers. These sub-carriers are orthogonal to each other. Its main advantages are multipath delay spread tolerance, high spectral efficiency, immunity to Frequency Selective Fading Channels, efficient modulation and demodulation process which is performed by computationally efficient Inverse Fast Fourier Transform (IFFT) and Fast Fourier Transform (DFT) operation respectively. An important disadvantage of OFDM is the carrier frequency offset which disturbs the orthogonality among the carriers and results Inter carrier interference (ICI). The undesired ICI degrades the performance of the system Keywords— Frequency Spectrum, SIR, Power of Desired Signal, Fading and AWGN, OFDM, ICI