An improved preamble detection method for LTE PRACH in high-speed railway scenario

In high-speed railway scenario, Doppler frequency shift influences the performance of preamble detection by inducing pseudo correlation peaks at the receiver side of Physical Random Access Channel (PRACH). To solve this problem, an improved preamble detection method which is carried out by two steps with combined detection thresholds is proposed in this paper. The first step is to detect the correlation peaks by each root Zadoff-Chu (ZC) sequence and the second step is to detect the exact number of random access users by search window. The superiority of the proposed method over the traditional method is verified in performance and flexibility to various propagation channels. Under the condition of different preamble formats, simulation results show that the performance of detection probability of the proposed method is at least 3dB better than the protocol requirement.