Research On Frequency Offset Estimation Algorithm And FPGA Implementation

Carrier synchronization is the key problem in digital communication system. Owing to the carrier frequency offset between the transmitter and the receiver in communication system and the influence of Doppler frequency shift, the phase of the received signal is changed, which can affect the receiver performance directly.Based on the classical algorithms of carrier frequency offset estimation and the system of OQPSK carrier synchronization, a novel OQPSK carrier synchronization scheme has been proposed in this thesis. The good performance of the proposed algorithm has been achieved by improving the frame starting position detection. That is, the matched filtering operation is utilized on the basis of the received signal's auto-correlation arithmetic. Furthermore, in order to achieve better application in practical, a suitable frequency offset estimation algorithm is chosen. Simulation results validate that the proposed algorithm has lower threshold of the signal-to-noise ratio, larger frequency offset estimation range and better estimation accuracy than the existed algorithms.A high efficiency FPGA scheme, which optimizes the hardware implementation and avoids a vast number of auto-correlation calculation about the frame starting position detection algorithm and frequency offset estimation algorithm, is presented. The high efficiency FPGA scheme not only can reduce the hardware resources occupancy rate, but also obtain low computational complexity by employing those overlapping data of the relevant operation. Finally, the simulation and experimental results demonstrate the effectiveness of the proposed FPGA scheme.