Carrier Synchronization Technique And ADS Emulate Of All-Digital Receiver In Satellite Communications

Nowadays, satellite communication develops rapidly since its dominance while compared with other means of communication modes. This paper emphasizes carrier recovery techniques in satellite communication. Lots of simulations have been made with ADS (Advanced Design System) which produced by AgilentTechnologies. It has powerful function, so it is universal acceptanted and in general use. This paper shows the simulation with ADS. It provides practical application of a certain reference value. In the satellite data transmission systems, carrier synchronization is to be able to better carry out demodulation. Therefore, first introduce satellite communications of modulation and demodulation techniques as paving the way. Carrier Synchronization in the study, divided into two parts: carrier frequency offset and phase offset research. Carrier Frequency Offset Estimation and correction gives three different ways:Offset rough estimate, Offset subtle estimate, and the open-loop rapid estimation. The last one is the improvements of existing carrier frequency offset estimation and its ADS simulation test performance significantly higher than the other two. It estimated frequency speed and low-noise ratio at the same time have a more stable performance which met for the rapid transmission.Carrier phase offset in partial estimates and correction, several research methods are given: the maximum likelihood method, PLL, and the very applicable to the burst OQPSK phase offset rapid estimation method. Particularly the last algorithm, based on the actual project requirements, of the existing open-loop algorithm improvement. It meets sudden channel transmission characteristics, theoretical analysis, rapid capture capability. Among the three methods, burst OQPSK phase offset rapid estimation has universal significance for mobile communications, Satellite communications needs of burst transmission mode. Finally, focuses on the famous Cramer-Rao bound, burst OQPSK phase offset rapid estimation method simulated by ADS,results with the theoretical value compared is satisfied which approves its superiority again.