The Research Of The Procedure Of The UE's Access In LTE FDD Base-band System

The ultimate target of the mobile communication is"personal communication",which means communication with anyone in anywhere and anytime and any types. Now we almost can communicate with other people in anytime and anywhere, but not any service, due to the bandwidth limitation and various services.In order to keep the durative rivalrousness of the mobile communication,3GPP proposed the LTE systems to improve the performance, which apply the OFDM,MIMO,AMC and scheduled etc. We study the procedure of the UE's access of LTE FDD system in this paper. The procedure of the UE's access includes two pivotal aspects: initial cell search and random access.By initial cell search,the UE which just boot-strap captures the time and frequency synchronization and distinguishes the cell ID at the same time.In this way the UE has been establish connection with eNodeB.And then, by random access the UE obtains uplink time synchronization and requests resources allocation.So the UE and eNodeB can communicate normally.The content of this thesis is as follows:Firstly, This paper introduces the background of market and technology,and the target of performance of the LTE;then describes the OFDM technology and the RTT of the LTE, the downlink is applied the OFDMA, which can effectively support the various bandwidth and flexible scheduled methods; the uplink is applied the SC-FDMA, which can also support the flexible scheduled methods and the low PAPR;And then describe the downlink synchronization and cell search mainly,design the structure of the SCH and the SCH sequence,and then give the scheme of the base-band detection algorithm. Finally,we emphasize the uplink random access,which is included the time and frequency structure,the principle of selecting the preamble sequence,the procedure of random access and the scheme of the base-band detection algorithm.