Reducing ICI Effect in OFDM System Using Low-Complexity Kalman Filter Based on Comb-Type Pilots Arrangement

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Journal Title, Volume, Page: 
International Journal of Communication Systems, 24:53–61
Year of Publication: 
2011
Authors: 
Allam Mousa
Electrical Engineering Department, An Najah University, Nablus
Current Affiliation: 
Department Of Electrical Engineering, Faculty Of Engineering, An-Najah National University, Nablus, Palestine
Hala Mahmoud
Electronics Engineering Department, Al-Quds University, Jerusalem
Preferred Abstract (Original): 
In OFDM systems, time-varying channels destroy orthogonality between subcarriers causing Inter-Carrier Interference. To reduce this effect, a Kalman filter, as a benchmark, is used for channel estimation, based on comb-type pilot arrangements of the OFDM system. An advantage of comb-type pilot arrangements in channel estimation is the ability to track the variation of the channel caused by Doppler frequency. Kalman method has been proposed to estimate the channel frequency response (CFR) at the pilot locations, then CFR, at data subchannels, is obtained by means of interpolation between estimates at pilot locations. The low-complexity Kalman method is introduced to reduce the complexity of the system while achieving the same BER/SNR. Different types of interpolations have been also compared such as Low-pass, Spline-cubic and Linear interpolation methods. The BER/SNR performance of BPSK modulation schemes are considered for time varying Rayleigh fading channels. Our results has shown that the low-complexity Kalman estimation, used with the pilot arrangement and a suitable interpolation method, gives almost the same performance as that of the Kalman method specially for low SNR values and hence the effect of Doppler shift effect is controlled.
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