Theoretical Analysis of Decision Directed Block Iterative Channel Estimation for OFDM Mobile Radio

Koichi ADACHI  Masao NAKAGAWA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E90-B   No.7   pp.1764-1772
Publication Date: 2007/07/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.7.1764
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
Keyword: 
OFDM,  iterative channel estimation,  theoretical analysis,  

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Summary: 
Orthogonal frequency division multiplexing (OFDM) is one of the promising transmission techniques for next generation mobile communication systems. Accurate channel estimation is essential for coherent OFDM signal transmission. So far, many pilot-assisted channel estimation schemes have been proposed. In the case of packet transmission, each received packet can be repeatedly processed by decision feedback to improve the channel estimation accuracy, resulting in a decision directed block iterative channel estimation (DD-BICE). However, decision feedback of erroneously detected data symbols degrades the packet error rate (PER) or bit error rate (BER) performance. In this paper, theoretical analysis is presented for the DD-BICE taking into account the decision feedback errors assuming quadrature phase shift keying (QPSK) data modulation. A 2-dimensional (2D) averaging filter is used for reducing the negative impact of decision feedback errors. The impacts of 2D averaging filter and antenna diversity reception are discussed and the validity of the theoretical analysis is confirmed by computer simulation.