Preamble Design Technique for Accurate Timing/Positioning in High Doppler Environments

Accurate estimation of timing is essential for positioning in cellular systems because propagation delays from neighboring base stations are used to calculate the position of a mobile station. A preamble design technique for accurate timing estimation in cellular systems with high mobility, such as autonomous driving and unmanned aerial vehicles, is proposed herein. A generalized Zadoff-Chu (ZC) sequence is defined and decomposed into multiple short subsequences to reduce the Doppler effect on the timing estimation. The performance loss caused by the short sequence length is compensated by combining the subsequences using the repetition property of the ZC sequence. The properties of autocorrelation and cross-correlation of the generalized ZC sequence that employs a receiver processing (RP) scheme (subsequence decomposition and combining) are analyzed in the presence of Doppler. Finally, the suitability of the proposed sequence with the RP scheme, for accurate timing estimation in multicell environments with a high Doppler, is demonstrated using simulation results.