Research And Implementation Of Cell Search In TDD LTE System

With its advantages of high spectrum efficiency, high peak rate and wide range of coverage, LTE system obtains further research by 3 GPP national standardization organization and widely deployment by various countries'mobile operators. The LTE terminal equipment must be able to acquire the target cell identity, downlink timing and frequency synchronization through the cell search process, afterwards demodulate the broadcast channel for system information to establish communication links, so cell search is a critical physical layer procedure in the TDD LTE system. Implementation of cell search process requires a lot of real-time computational, consumes hardware processing resources thus constraints the improvement of terminal performance. By research of LTE cell search principle and pennetrate deeply into the characteristics of synchronization signals, improved search algorithm are proposed to reduce the computational complexity and save terminal's hardware resources.1. The primary sync signals'characteristics are penetrated deeply, and an improved detection algorithm is proposed to reduce the sliding correlation computation by use of the center symmetry and conjugate symmetry of the primary sync signal.2. The characteristic of GP existing in TDD frame structure is exploited, and a GP based PSS detection method is proposed. Firstly use power windows to search GP position, and then take advantage of special sub-frame configuration in TDD LTE system to minify PSS search scope, thereby reducing the computation of the PSS sliding correlation. The theoretical basis and realization methods to determine power windows length and power ratio threshold parameters are given.3. The SSS signal scrambling methods are analyzed in detail. Two conventional algorithms of sequence detection and joint detection are introduced. By use of M sequence matrix and the Hadamard matrix transformation relation, a Hadamard based SSS detection algorithm is proposed. The theoretical basis of the improved algorithm is derived in detail and a concrete realization is designed.4. A link level simulation platform is build, for test and verify PSS and SSS detection algorithms.