Abstract
In this letter, we develop a channel estimation algorithm for a downlink multi-carrier code division multiple access system in the context of two-path successive relaying transmission. We employ the expectation maximization tool to get the maximum likelihood estimate of the channel impulse responses of the direct and relays links. The proposed algorithm proceeds in an iterative structure and utilizes the soft information given by the demodulator as a priori probabilities to refine the estimation process, without causing overhead to the demodulation execution. The simulation experiments are carried out to assess the effectiveness of the proposed estimator.