在第四代通訊技術中長期演進技術(Long Term Evolution，LTE)占有十分重要的地位，並隨著LTE技術的日益成熟出現了改良版的LTE Advanced(LTE-A)。在LTE-A中以多重載波聚合技術、結合多天線MIMO技術，大幅的提升傳輸速度。LTE中的下行鏈路為正交分頻多重存取(Orthogonal Frequency Division Multiple Access，OFDMA)系統，此系統正是由正交分頻多工(Orthogonal Frequency Division Multiplexing，OFDM)演進而來，可使頻譜效益增加。本篇論文中對於LTE訊號的傳輸以軟體模擬進行探討並進一步以硬體方式實現。
在硬體中以Verilog硬體描述語言設計並實現LTE下行鏈路的發射機與接收機，而平台上使用FPGA(Field Programmable Gate Array)板子實現。發射機訊號處理模組中設計了串列與並列轉換處理器、星座圖映射器、參考訊號與主同步訊號置入器、子載波擺放器、反快速傅利葉轉換器以及循環字首置入器。在接收機方面的模組包括了訊號同步器(包括符元時間、載波頻率)、快速複利葉轉換器、子訊框同步器、通道估測以及通道等化器。;LTE(Long Term Evolution) plays an important role in the fourth generation of mobile phone and mobile communication technology. Moreover, LTE technologies is getting mature enough to develop LTE Advanced(LTE-A) technology. It speeds up transmission by using Carrier Aggregation and MIMO technology. On the downlink transmission, the LTE system uses OFDMA(Orthogonal Frequency Division Multiple Access) technology, which is derived from OFDM(Orthogonal Frequency Division Multiplexing). It can increase spectrum efficiency. In this thesis, we simulated LTE signal transmission with MATLAB software and tabulated the real transceiver with hardware technology.
In hardware, we use verilog hardware description language to conduct design and implement LTE downlink transceiver. On platform, we use FPGA(Field Programmable Gate Array) board. The transmitter includes parallel-to-serial processor, constellation mapper, reference signal and primary synchronization signal inserter, subcarrier placer, IFFT processor and cyclic prefix inserter. The receiver includes signal synchronizer(includes symbol and subcarrier frequency), FFT processor, subframe synchronizer, channel estimator and channel equalizer.
