A simple suboptimal bit-level demapper algorithm of M-ary QAM is presented. Both bit-level and optimal maximum likelihood (ML) demodulators in hard decision for M-ary QAM, combined with orthogonal frequency division multiplexing (OFDM), are compared in terms of bit error rate (BER). The performance of this bit-level algorithm is shown to be the same as that of the optimal ML method theoretically when E bNois high. Furthermore, novel soft bit values for soft decoding are derived from this bit-level demapper algorithm. At BER=10−4, the BER of coded M-QAM-OFDM with rate 1/2 significantly outperforms the hard decoding by 10 dB (QPSK) and 9 dB (64QAM) in COST207 typical urban fading channels, respectively.
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 49/05M, Masters Abstracts International|
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