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Joint time-frequency diversity for single-carrier block transmission in frequency selective channels

Abstract:

In time-varying frequency selective channels, to obtain high-rate joint time-frequency diversity, linear dispersion coded orthogo-nal frequency division multiplexing (LDC-OFDM), has recently been pro-posed. Compared with OFDM systems, single-carrier systems may re-tain the advantages of lower PAPR and lower sensitivity to carrier fre-quency offset (CFO) effects, which motivates this paper to investigate how to achieve joint frequency and time diversity for high-rate single-carrier block transmission systems. Two systems are proposed: linear dispersion coded cyclic-prefix single-carrier modulation (LDC-CP-SCM) and linear dispersion coded zero-padded single-carrier modulation (LDC-ZP-SCM) across either multiple CP-SCM or ZP-SCM blocks, respectively. LDC-SCM may use a layered two-stage LDC decoding with lower complexity. This paper analyzes the diversity properties of LDC-CP-SCM, and provides a sufficient condition for LDC-CP-SCM to maximize all available joint fre-quency and time diversity gain and coding gain. This paper shows that LDC-ZP-SCM may be effectively equipped with low-complexity minimum mean-squared error (MMSE) equalizers. A lower complexity scheme, lin-ear transformation coded SCM (LTC-SCM), is also proposed with good diversity performance. Copyright © 2012 The Institute of Electronics, Information and Communication Engineers.