A joint H2–H ∞ algorithm for fading channel estimation and symbol detection

Abstract—This paper proposes a novel recursive method to jointly estimate the Rayleigh fading channel and the trans-mitted symbols for current wireless communications sys-tems. Starting from the well-known Jakes ’ model for the wireless fading channel, an autoregressive (AR) represen-tation is produced by the means of Levinson–Durbin algo-rithm. This allows for a state-space approach to the chan-nel estimation problem, for which the MMSE solution is provided by the celebrated Kalman filter. When the ro-bustness of the estimator is important, the H ∞ algorithm may be employed instead. It is shown that these algorithms can be combined in order to recover the transmitted sym-bols and to obtain improved estimates for the envelope and phase of the channel. The paper also proposes a blind chan-nel envelope estimator based on the H ∞ algorithm. I