Abstract
A method to reduce Peak to Average Power Ratio (PAPR) in OFDM systems with null subcarriers is considered. For a given optimal or suboptimal pilot set designed for channel estimation and/or synchronization, deliberate introduction of pilot phases can lead to minimum PAPR of the time domain OFDM signals. In this paper, we presented a novel algorithm based on cross entropy (CE) optimization techniques to design phase to each pilot in order to minimize the peak pilot tones. Compared to the other exhaustive search methods, the proposed algorithm converges fast to the near optimal phase. Due to its high convergence rate, proposed scheme has the potential to make practical design of phase for different pilot subcarrier sets. The effectiveness of the proposed pilot phase design is demonstrated with several examples including the one based on the IEEE 802.11a.
