Soft-feedback MMSE equalization for non-orthogonal frequency division multiplexing (n-OFDM) signal detection
| Autor: | Norulhusna Ahmad, S. Kamilah Syed-Yusof, Tad Matsumoto, Khoirul Anwar, Norsheila Fisal |
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| Rok vydání: | 2012 |
| Předmět: |
Orthogonal frequency-division multiplexing
Transmitter Bandwidth (signal processing) Spectrum Efficiency Overlapping subcarrier EXIT chart Frequency-division multiplexing symbols.namesake Additive white Gaussian noise Frequency separation symbols Bit error rate Electronic engineering Algorithm OFDM Mathematics |
| Zdroj: | WSA |
| DOI: | 10.1109/wsa.2012.6181215 |
| Popis: | A frequency division multiplexing technique, nonorthogonal frequency division multiplexing (n-OFDM), is proposed in [1]- [2] to enhance the efficiency of bandwidth utilization. This paper reveals that the smaller the frequency separation, the larger sum capacity can be achieved compared with the conventional OFDM technique. However, n-OFDM system introduces inter-carrier interference (ICI) at the transmitter because the orthogonality between the subcarriers no longer holds. Moreover, since the channel covariance matrix of n-OFDM has high condition number when the overlapping factor, 1 - α, is large, conventional linear detectors suffers from severe noise enhancement. To solve this problem, this paper proposes the use of soft cancellation- minimum mean-squared error (SCMMSE) turbo equalization. Binary constellation constrained mutual information (CCMI) is calculated by utilizing the area property for the EXtrinsic Information Transfer (EXIT) chart of the SC-MMSE equalizer. Results of the EXIT chart analysis and bit-error-rate (BER) simulations in additive white Gaussian noise (AWGN) channel are presented. |
| Databáze: | OpenAIRE |
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