Random access preamble design based on time pre-compensation for LTE-satellite system

Because of the integration of long term evolution (LTE) technology and mobile satellite communication systems, uplink access technology for LTE-based geo-stationary earth orbit (GEO) satellite has become a popular research topic for satellite system. In order to solve the problem of unreasonable design for physical random access channel (PRACH) signal structure and reduce the effect of time uncertainty, this paper proposes a novel random access preamble based on time pre-compensation (TPC) for LTE-Satellite (LTE-S) system. In this scheme, by applying the method of non-linear least squares, the user terminal (UT) can use the receiving power to estimate the communication round trip delay (RTD) and based on the transmission delay of the beam center and the satellite, RTD can be compensated before transmission. Therefore, the preamble length and duration can be reduced without related to the maximum of RTD. In order to verify the performance of the scheme, the MATLAB is used to build a test system. The simulation results show that the proposed preamble satisfies the requirements of LTE-S system, and the better performance than previous researches is obtained.