Research On Synchronization Technologies Of Next Generation Broadcasting-Satellite

Satellite communication plays an important role in the field of the world's wireless communication networks.With the development of society,the number of mobile terminals increases with a high speed,and the demand for wide area mobile communication services is very urgent.China's Next Generation Broadcasting Network on Satellite(NGB-S)is a standard for satellite mobile broadcasting and is currently in the drafting stage,which provides rich mobile communication services for mobile terminals.Receiver synchronization technology is an important technology in wireless communication system.It is also the first module to be implemented in the receiver algorithm.Whether the synchronization module can work properly in very bad scenarios such as low SNR and high carrier frequency offset is the key factor in NGB-S system.This paper focuses on the synchronization technology in satellite mobile communication system.Firstly,several classic models and simulation methods of satellite mobile channel are introduced,and the performance loss due to synchronization error in single-carrier system is analyzed.Secondly,this paper introduces and analyzes the structure of NGB-S preamble in detail,and introduces the carrier synchronization algorithms based on the preamble.This paper presents a low-complexity integer frequency offset estimation algorithm.The complexity of the proposed algorithm is compared with the existing algorithms.A large number of simulation experiments show that the proposed algorithm has no significant loss of carrier estimation performance compared with the traditional algorithm.Then,frame synchronization algorithm based on preamble is studied,and an improved frame synchronization algorithm is proposed.The proposed algorithm treats the fixed synchronization sequence P1 and the signaling sequence P2 in the preamble separately.Through a lot of simulation experiments,the frame synchronization performance of different algorithms is compared,the results show that the proposed algorithm has better frame synchronization performance than traditional algorithms.Finally,in order to optimize the satellite signals coverage,a scheme of terrestrial supplementary network and satellite co-coverage is proposed in this paper.Different from the traditional terrestrial broadcast single-frequency network(SFN),the scheme proposed in this paper adopts the IEEE1588v2 standard clock as the reference time and frequency of the transmitters.The switches at the transmitter end get synchronized with the master clock by IEEE1588v2 protocol,and provide reference time and frequency signal for the transmitters.The prototype system was developed by the authors.The test results show that the proposed scheme has the same performance as the traditional SFN.