Research On Key Technology Of LTE Random Access Procedure

As the first step of user request access to networks in the communicationprocess, random access procedure is an important part of LTE communicationnetwork. Now, the random access preamble detection algorithm which is widelyapplied to LTE communication system is a kind of time-domain detectionalgorithms. Traditional time-domain detection algorithms include dynamicdetection threshold and predefined detection threshold algorithm. Because oftraditional dynamic detection threshold algorithm needs to adjust threshold valueaccording to SNR, it can increase its computation complexity and lead to largenetwork delays and network loads. Although another algorithm has highefficiency calculation, its detection performance also needs to be improved.In this context, this paper has a deep research on preamble signals detectionalgorithm which is the key technology of LTE-FDD random access procedure.What’s more, it focuses on how to receive and detect preamble signals. Toimprove the performance of preamble detection, a proposal aiming at improvingpredefined detection threshold algorithm is proposed. Then, the realized solutionof PRACH receiver on FPGA and detailed design solutions of modules are given.Next, the simulation system of preamble signals detection in random accessprocedure based on Matlab is designed and builted, which can set all kinds ofsimulation parameters through graphic interface. On this basis, to meet theLTE-FDD test requirements, different channel conditions and configurationparameters are respectively set under high-speed and low-speed mode to simulatethe improved algorithm, the simulation results show that the performance ofimproved algorithm can completely meet the LTE standard. Finally, bycomparing the simulation results of traditional predefined threshold detectionalgorithm and the improved algorithm in the high-speed mode, the result proves that the improved algorithm can efficiently improve detection performance ofrandom access signals.