A Novel Zero-Order FIR Zero-Forcing Filterbanks Equalizer Using Oblique Projector Approach for OFDM Systems

Chun-Hsien WU  Shiunn-Jang CHERN  

Publication
IEICE TRANSACTIONS on Communications   Vol.E88-B   No.12   pp.4545-4557
Publication Date: 2005/12/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.12.4545
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Devices/Circuits for Communications
Keyword: 
filterbanks equalizer,  oblique projector,  CP-OFDM,  IBI cancellation,  ISI cancellation,  

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Summary: 
In conventional OFDM systems, the effect of inter-block-interference (IBI) can be completely removed by inserting sufficient redundant symbols between successive transmission blocks. In this paper, based on the reformulated received block symbols of the discrete multirate filterbanks model, a new transceiver model for the cyclic prefix (CP) OFDM systems is proposed, associated with the oblique projector technique (view as the pre-processor for achieving IBI-free). Consequently, a novel ISI-free receiver with the zero-order FIR zero-forcing (ZF) filterbanks equalizer can be devised, under noise-free environment. For performance comparison the bit-error-rate (BER) is investigated for the cases of noisy and noise-free channels. In all cases, viz., the length of CP is shorter or longer than the order of the channel impulse response, we show that the same BER performance compared with the one suggested in [3] can be achieved, under the same assumptions and conditions. Since a simple cascade configuration of the IBI cancellation using the oblique projector followed by the ISI cancellation using the zero-order FIR ZF filterbanks equalizer can be realized for OFDM systems with sufficient or insufficient CP, the complexity of transceiver design can be reduced.