Analysis And Design Of OFDM Baseband System Based On FPGA

Orthogonal Frequency Division Multiplexing is a multi-carrier modulation and multiplexing technology with many advantages such as less Inter Carrier Interference and Inter Symbol Interference,anti-frequency selective fading and multipath effects,higher spectral efficiency.In the case of higher requirements for wireless data transmission speed and radio frequency resources becoming increasingly scarce,the OFDM technique is especially suitable for the wireless communication requirements of high-speed, broadband and mobile.With the gradual improvement of theory and related implementation techniques,European Digital Audio and Video,WLAN and Broadband Wireless Access have launched relevant physical layer standard and the most of 4G standard’s physical layer in the commercial also use the OFDM related technology.So,OFDM has become the core technology of the physical layer of wireless communication system.The thesis firstly introduces the basic principle and system architecture of OFDM technology and the related physical layer protocol about OFDM application,and performing the MATLAB simulation of the waveform and spectrum of the OFDM symbol.We focus on the physical layer standard of IEEE802.11 a,and discuss the principle and implementation method of each module realization.Secondly,we describe the detailed design procedure of each system module.The transmitting end includes the scrambling module using pseudo random sequence,convolutional coding module with efficiency of 1/2,packet interleaving module,QPSK mapping module,IFFT processing module and the cyclic prefix insertion module.The receiving end includes the cyclic prefix removing module,FFT processing module,QPSK inverse mapping module, de-interleaving module,Viterbi decoding module and descrambling module.To ensure the system data uninterrupted processing,we design the Ping-Pong operation buffer unit.The associated control operation and clock management are completed by the main control module of each end respectively.Finally,we performed the functional simulation and testing of each module designed and the whole system.After testing,we verify the feasibility and correctness of design.