Joint Correction Of Time-interleaved Mismatches And Channel In OFDM System

In the era of digital signal, digital signal processing technology has become an important part of digital communication system where Analog-to-Digital Converter connects analog to digital. Not only the high sampling resolution but also the high speed is the need of ADC in multi-Gbps communication systems. Limited to the manufacturing craft, a single ADC is hard to meet the needs of systems mentioned above. Time-Interleaved ADC becomes the proper substitute of tradition ADC structure. However, errors caused by channel mismatches degrade the overall performance of the communication systems. In this thesis, we investigate the joint mismatch and channel compensation for OFDM receiver with Time-Interleaved ADC.Firstly, we model the overall system of OFDM receiver with Time-Interleaved ADC and analyze system performance considering the time and gain mismatches. Besides, mismatches and channel dispersion are compensated jointly, with the system performance being overall considered rather than ADC performance. In addition, the number of sub-ADC has been demonstrated that proper design can simplify the joint compensation algorithm.Then, matrix inversion as the key technology of the joint compensation algorithm has been discussed in this thesis. From the perspective of algorithm and implementation, QR-decompositon, Cholesky-decompositon and Adjoint-matrix inversion algorithms have been compared.Finally, we propose the circuits design for joint compensation algorithm and verify the correction and availability by using the Xilinx Virtex-6 FPGA. Simulation and testing report shows that under the condition of 10% mismatches, system BER has dropped from-210 to nearly-410.Maximum operating frequency of designed circuit can reach 251.2MHz.