Study Of Random Access Preamble Detection Of LTE-FDD And Design Of LTE-FDD PRACH Simulation Model

The booming development of wireless Internet, the popularization of smart phone and the dramatically increased number of cell phone users, making the existing3G network more and more can’t satisfy users’need of higher data rate services. So LTE technology arises at the historic moment. LTE is bringing new prospects to the wireless communication market, its advantages of the lower delay, the higher transmission rate, the configurable spectrum and the good mobile performance, attracted the most of the world’s telecom operators.In this thesis the random access process of the frequency division duplex mode of LTE were deep studied. At first the background of LTE technology, the demands and the advantages of LTE were introduced and analyzed. Then the conception of random access, the purpose of random access and the principles of past communications systems were summarized, and the classification and uses of LTE random access and were detailed.Following the PRACH (physical random access channel) signal generation progress of LTE-FDD is elaborated; Corresponding to the channel conditions of LTE-FDD the LTE Raleigh fading channel is designed; Based on the receiver of LTE-FDD PRACH, the testing method of preamble sequence, and the handling method of the "Pseudo peak" caused by Doppler frequency shift were put forward. At the same time the semi-dynamic threshold peak detection method was given to improve fix-threshold method.Besides the above contribution, the system simulation model made up by transmitter, receiver and channel, which is strictly according to the3GPP’s definition and whose system parameter can be configured free, was designed in the MATLAB environment. Finally in this thesis the most comprehensive PRACH system was simulated according to the LTE-FDD testing requirement using different configuration parameters to prove the reliabilities of signal generation module, the designed channel and detection receiver module. At the same time the semi-dynamic threshold detection algorithm and the fixed-threshold method were compared.The results show that, the design of LTE-FDD PRACH simulation model, especially Raleigh fading channel model, has important guiding significant for designing the eNB Base station. It can help the engineers shorten the design and commissioning period. The semi-dynamic threshold detection algorithm can effectively improve the detection performance of PRACH signal.