A SDM-COFDM Scheme Employing a Simple Feed-Forward Inter-Channel Interference Canceller for MIMO Based Broadband Wireless LANs

Satoshi KUROSAKI  Yusuke ASAI  Takatoshi SUGIYAMA  Masahiro UMEHIRA  

IEICE TRANSACTIONS on Communications   Vol.E86-B   No.1   pp.283-290
Publication Date: 2003/01/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Multiple Access and Signal Transmission Techniques for Future Mobile Communications)
SDM-COFDM,  MIMO,  propagation matrix,  likelihood-weighting,  soft decision Viterbi decoding,  

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This paper proposes a space division multiplexed - coded orthogonal frequency division multiplexing (SDM-COFDM) scheme for multi-input multi-output (MIMO) based broadband wireless LANs. The proposed scheme reduces inter-channel interference in SDM transmission with a simple feed-forward canceller which multiplies the received symbols by the estimated propagation inverse matrix for each OFDM subcarrier. This paper proposes a new preamble pattern in order to improve power efficiency in the estimation of the propagation matrix. Moreover, the proposed likelihood-weighting scheme, which is based on signal-to-noise power ratio (SNR) of each OFDM subcarrier, improves the error correction performance of soft decision Viterbi decoding. Computer simulation shows that the proposed SDM-COFDM scheme with two transmitting/receiving antennas doubles the transmission rate without increasing the channel bandwidth and achieves almost the same PER performance as the conventional single-channel transmission in frequency selective fading environments. In particular, it achieves more than 100 Mbit/s per 20 MHz by using 64QAM with the coding rate of 3/4.