Blind joint detection and channel estimation in space-frequency diversity systems using time-varying linear constellation precoding

Abstract

This work formulates a new multiantenna receiver for the blind decoding of space-frequency codes in multiantenna systems. The proposed transmit signal design combines frequency-domain Vandermonde spreading with a time-varying linear constellation precoding. The latter consists in extending constellation rotation across multiple symbols periods. Exploiting the algebraic structure of this combined transmit processing, the received signal is formulated as a three-way array following a nested parallel factor model with a rich multilinear structure. A joint channel estimation and symbol decoding process is derived out by resorting to a nested alternating least squares algorithm. We also discuss identifiability conditions for the proposed receiver, shedding light on the intrinsic tradeoffs involving space, time and frequency diversities exploited by the proposed blind receiver. Numerical results are provided for bit error rate (BER) performance evaluation for some system configurations.