Research And Implementation Of Carrier Synchronization In Single-Carrier And Multi-Carrier Communication Systems

Single Carrier(SC) system and Orthogonal Frequency Division Multiplexing(OFDM) system are widely used at present. The advantage of SC system is that its PAPR is much lower than that of the corresponding OFDM system. As a comparison, OFDM system can achieve higher spectrum efficiency. Currently there are some communication standards adopting a combination of SC and OFDM. Carrier frequency offset estimation has become a hot research issue in both systems. Doppler shift and oscillator frequency deviation can cause carrier frequency offset, and carrier frequency offset will cause inter-carrier interference thereby affecting the performance of the receiver. In conclusion, it is important for the receiver to obtain accurate carrier frequency synchronization. The existing algorithms have the shortcoming of high complexity or insufficient estimation range. Therefore, the thesis studies the carrier frequency offset estimation methods in both the single-carrier communication system and the DVB-T2 system, and the FPGA implementation is also competed. Our work includes:1. We summarized the technical background and the latest progress of single carrier communication systems, especially the single carrier frequency domain equalization system. One hand, we studied carrier synchronization technology based on the basic framework and mathematical model of the SC-FDE system; on the other hand, we summarized the background and development of the mobile multimedia broadcasting technology, including DVB-T2. Based on mathematical analysis,the paper shows the importance of carrier synchronization technology in the two systems mentioned above.2. We studied the carrier synchronization algorithm in SC communication system. In this paper, we analyze the estimation range of existing algorithms, a carrier frequency offset estimation algorithm with low complexity is proposed for the considered SC-FDE system with a special frame structure. This algorithm combines the CP-based algorithm and the pilot-based iteration algorithm. The performance of the algorithm is verified by simulation. Finally, the simplified algorithm is implemented by using VHDL and tested in the FPGA platform.3. We studied the carrier synchronization algorithm in DVB-T2 system. At first, we introduces the pilot resources in DVB-T2, which is more abundant when compared to DVB-T. The P1 symbols can be used for fast timing synchronization and carrier frequency offset estimation. In this paper, we study the integeral CFO estimation and the fractional CFO estimation, and several existing algorithms are evaluated by simulations, including P1 symbols based fractional CFO estimation algorithm, cyclic prefix based fractional CFO estimation algorithm, the continual pilot based integer CFO estimation algorithm, and the P1 symbols based integer CFO estimation algorithm. Finally, the FPGA-based P1 symbols based integer CFO estimation algorithm is realized in VHDL.