Effect of Pulse Shaping Filters on a Fractional Sampling OFDM System with Subcarrier-Based Maximal Ratio Combining

Mamiko INAMORI  Takashi KAWAI  Tatsuya KOBAYASHI  Haruki NISHIMURA  Yukitoshi SANADA  

IEICE TRANSACTIONS on Communications   Vol.E92-B    No.5    pp.1484-1494
Publication Date: 2009/05/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.1484
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Radio Access Techniques for 3G Evolution)
OFDM,  fractional sampling,  diversity,  pulse shaping filter,  

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In this paper, the effect of the impulse response of pulse shaping filters on a fractional sampling orthogonal frequency division multiplexing (FS OFDM) system is investigated. FS achieves path diversity with a single antenna through oversampling and subcarrier-based maximal ratio combining (MRC). Though the oversampling increases diversity order, correlation among noise components may deteriorate bit error rate (BER) performance. To clarify the relationship between the impulse response of the pulse shaping filter and the BER performance, five different pulse shaping filters are evaluated in the FS OFDM system. Numerical results of computer simulations show that the Frobenius norm of a whitening matrix corresponding to the pulse shaping filter has significant effect on the BER performance especially with a small numbers of subcarriers. It is also shown that metric adjustment based on the Frobenius norm improves BER performance of the coded FS OFDM system.