Iterative Reception Employing Sparse Channel Estimation for OFDM Systems

OFDM transmission schemes are adopted in the integrated services digital broadcasting-terrestrial (ISDB-T), the downlink of long term evolution (LTE), etc. In most cases, there are not many delayed paths in the propagation environments, i.e., the wireless channels are likely to be sparse. In addition, when the receiver moves rapidly, the accuracy of channel estimation deteriorates significantly. In order to alleviate the deterioration, the iterative channel estimation scheme with the tap selection and the least mean squares (LMS) algorithm has been studied. For further improvement of the channel estimation accuracy, this paper investigates a channel estimation scheme employing the optimization method with L1-norm regularization, called fast iterative shrinkage-thresholding algorithm (FISTA), and proposes an iterative receiver employing such a channel estimation scheme for OFDM systems. For evaluating the performance of the proposed scheme, computer simulations are conducted under the condition of ISDB-T with the scattered pilots (SP)-OFDM signal. It is shown that the proposed method can estimate the sparse channel impulse response more accurately than the conventional method.