The Research And Implementation Of OFDM Baseband And If Siganl Processing System

Orthogonal frequency division multiplexing(OFDM) has been paid to extensive attentions due to its high spectrum efficiency and ability of resistance to multipath interference in recent years. OFDM has been the key technology in the 4G wireless communication system nowadays. Full digital implementation of communication system has been a trend because of the development of software radio technology and its flexibility and openness. Therefore, taking into account the above background, it is meaningful to study the full digital implementation of OFDM baseband and IF system.In this thesis, some aspects of OFDM are simply presented, such as the development of OFDM, the advantages and disadvantages of OFDM, the basic principles and key technology of OFDM. Based on these theories, the whole structure of OFDM baseband and IF signal processing system is obtained from the physical layer protocol of IEEE802.11 a. Then, the principles and hardware implementations of modules, such as OFDM baseband transmitter, digital up converter, DAC, ADC, digital down converter and OFDM baseband receiver, have been discussed in detail. The hardware implementation of the whole system has been completed with Verilog, and each module has been tested with chipscope. Since the algorithm of receiver has great impact on system performance, Gaussian noise, frequency offset and simple multipath have been added to data symbols of transmitter as the test data. The test results show that the receiver can overcome a range of signal noise, frequency offset and simple multipath interference.The debugging of the whole system on the hardware platform which consists of Xilinx’s Virtex6 and TI’s DAC3152, ADS4229 has been completed. At last, detailed test scheme has been set down, and the test of OFDM baseband and IF system on the one board and double board has been made. Through the test, it is observed that the decoded data symbols are identical to the original data symbols, and it is verified that the system have correct function and certain performance, at the same time, the hardware platform can be used as signal processing platform of OFDM.