Blind channel shortening for uplink SC-IFDMA operating over highly-dispersive channels

The present paper proposes a blind channel shortening algorithm for uplink reception of a single-carrier interleaved frequency-division multiple-access (SC-IFDMA) system, affected by timing offsets (TOs) as well as carrier frequency offsets (CFOs), and transmitting over a highly-dispersive channel. Whenever the cyclic prefix (CP) cannot completely compensate for channel dispersion and TOs, a convenient strategy is to shorten the channel by time-domain equalization (TEQ) in order to ease signal reception. The proposed receiver exhibits a three-stage structure: the first stage performs blind channel shortening without requiring neither {\em a priori} knowledge of the channels nor preliminary compensation of the CFOs; the second stage performs multiuser CFO compensation; finally, to alleviate noise amplification effects possibly arising from CFO compensation, the third stage implements blind per-user signal-to-noise ratio (SNR) maximization. The performances of the proposed method are assessed and compared with those of existing algorithms by Monte Carlo computer simulations.