Technical Research And FPGA Implementation Of LTE Cell Search

The long term evolution (LTE) technology proposed by3GPP organization, withits high peak data rates, low latency, improved system capacity, and flexible bandwidthoperation, is becoming a mainstream4G technology specification for the next decade.Cell search is a basic function that must be supported by LTE system. Just it turnon, the mobile terminal performs a cell search to achieve timing and frequencysynchronization as well as cell identity to the base station. Because of OFDMtechnology, synchronization is especially important for LTE system. Cell search in LTEsystem should support a scalable bandwidth from1.25MHz to20MHz, which is alsodifferent from other cellular systems.Cell search consists of three parts: initial cell search, cell measurements, andhandover procedures. The cell measurements and handover procedures are set by thestandard, and different implementations only have a small impact on their performance,so initial cell search was mainly studied in this thesis. The initial cell search performedby the mobile terminal need process a large number of real-time data, how shouldcomplete the search procedure with low processing complexity and within a short timeis the focal research work.This thesis firstly introduces a brief history of the wireless communication systemas well as the research status and significance of cell search for the latest LTE system.Next, the basic concepts and theories are introduced in the second chapter. The mainresearch work, cell search algorithm design and hardware implementation, wasdiscussed by chapter three and four. Besides，we also presented the developmentplatform and tools, along with the FPGA implementation and verification results for cellsearch algorithm. Finally, the whole thesis was summarized and the future research wasprospected.The main research is focused on the design and hardware implementation of cellsearch scheme, providing a total solution for LTE cell search. On the designing ofalgorithm, each detection algorithm is analyzed, and some algorithm was simplified forthe need of hardware implementation. We also proposed two simplified practical algorithms for CP detection and SSS detection, the simplified algorithms have lowerimplementation complexity and the performance loss within acceptable limits. From theoverall implementation complexity considerations, we determined the algorithms ofPSS detection and frequency offset estimation. On the hardware implementation, thehardware sharing technique and the special computation unit specially designed strategyare employed to reduce hardware cost while implementing this system. The simulationresults shows, the implemented design can accomplish cell search procedures well.