Turbo Equalized Double Window Cancellation and Combining Robust to Large Delay Spread Channel

JunHwan LEE  Tomoaki OHTSUKI  Masao NAKAGAWA  

IEICE TRANSACTIONS on Communications   Vol.E92-B   No.2   pp.517-526
Publication Date: 2009/02/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E92.B.517
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies

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In orthogonal frequency division multiplexing (OFDM) the multipath exceeding the guard interval (GI) causes inter-symbol interference (ISI) and inter-carrier interference (ICI), thereby making it difficult to achieve high data rate transmission. In this paper, the double window cancellation and combining (DWCC), introduced in [14], is analyzed by investigating SINR distribution under different delay spread channels. The analysis indicates that the extension of processing window in iterative cancellation can have an adverse effect on the performance for small interference levels. In addition, the optimal combining of DWCC and turbo equalization (TE), named TE-DWCC, is investigated by varying the iterative cancellation procedure between DWCC and channel decoder and the decision feedback type such as hard decision feedback (HDF) or soft decision feedback (SDF). Finally, by changing interference level, code rate, and decision feedback type, the performance of TE-DWCC is compared with the conventional canceller that adopts turbo equalization in the exponentially distributed slow fading channel.