A reduced complexity channel estimation for OFDM systems withtransmit diversity in mobile wireless channels
Minn, H.; Dong In Kim; Bhargava, V.K.
Communications, IEEE Transactions on
Volume 50, Issue 5, May 2002 Page(s):799 - 807
Digital Object Identifier 10.1109/TCOMM.2002.1006561
Summary:A reduced complexity channel estimation for OFDM systems with
transmit diversity is proposed by exploiting the correlation of the
adjacent subchannel responses. The sizes of the matrix inverse and the
FFTs required in the channel estimation at every OFDM data symbol are
reduced by half of the existing method for OFDM systems with nonconstant
modulus subcarrier symbols or constant modulus subcarrier symbols with
some guard tones. The complexity reduction of half FFTs size and some
matrix multiplications is still achieved for constant modulus subcarrier
symbols with no guard tones. The price for the complexity reduction is a
slight BER degradation and for the channels with small relative delay
spreads, the BER performance of the reduced complexity method becomes
quite comparable to the existing method. An alternative approach for the
number of significant taps required in the channel estimation is
described which achieves a comparable performance to the case with the
known suitable number of significant taps. A simple modification which
reduces the lost leakage of the nonsample-spaced channel paths is also
proposed. This modification achieves a substantial performance
improvement over the existing method without any added complexity
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