Wireless channel estimation techniques using pilot carries in OFDM systems [articol]

Abstract

The objective of this study is to improve channel estimation accuracy in OFDM systems, which have high data rate and channel capacity and adequate performance in frequency selective fading channels. The first contribution of the paper lies in highlighting the appropriateness of the time-frequency representations for the analysis of OFDM communication systems. We show that the delay and Doppler spreading are the most important characteristics of a communication channel and we indicate how can be used the ambiguity function to estimate these characteristics. Next, we prove that all the on air wireless communication channels are identifiable. The channel estimation based on block-type and comb-type pilot arrangement is studied through different algorithms such as LS, MMSE, LMMSE. Experimental results highlight the merits of the method proposed.