Comparison of different channel estimation approaches for Block-IFDMA

SUMMARY In this paper, channel estimation for Discrete Fourier Transform (DFT) precoded Orthogonal Frequency Division Multiple Access (OFDMA) with block-interleaved subcarrier allocation per user, which is denoted as Block-Interleaved Frequency Division Multiple Access (B-IFDMA), is considered. Recent investigations are presented for new pilot insertion methods which exhibit different impact on the Peak-to-Average Power Ratio (PAPR) of the transmit signal and offer different possibilities of positioning the pilots in frequency domain. Each of these pilot insertion methods is combined with a corresponding algorithm to estimate the Channel Variations in Frequency Domain (CVFD). The Channel Variations in Time Domain (CVTD) are estimated by an improved Decision Directed Channel Estimation (DDCE) with joint iterative Wiener filtering which reduces the error propagation by considering certain neighbouring symbols jointly in each iteration step. The DDCE is compared to a Wiener interpolation filter for the estimation of CVTD. The combinations of pilot insertion method, estimation algorithm for CVFD and CVTD are compared in terms of the PAPR and the Mean Square Error (MSE) performance. Thereby, the impact of different pilot positions in frequency domain and time domain is investigated. Copyright © 2010 John Wiley & Sons, Ltd.