Design of Low Papr Preamble and Pilot Symbol for Channel Estimation in Ofdm Systems

We present the design of long preambles as well as pilot symbols for orthogonal frequency division multiplexing (OFDM) that jointly captures the aggregate effects of channel estimation error and peak to average power ratio (PAPR). To the preambles and pilot symbols designed to minimize the mean square error (MSE) of the channel estimate, we propose an algorithm based on cross entropy (CE) optimization techniques to design phases of the training symbols in order to minimize peak powers of the training symbols. Compared to the exhaustive search method, the proposed algorithm converges fast to the near optimal solution. Due to its high convergence rate, our proposed scheme has a potential to make practical design of phases for different pilot subcarrier sets. Several design examples including the one consistent with IEEE 802.11a/g are provided to illustrate the superior performance of our proposed method over the conventional standards.