J4 ›› 2014, Vol. 41 ›› Issue (1): 23-28+63.doi: 10.3969/j.issn.1001-2400.2014.01.005

• Original Articles • Previous Articles     Next Articles

Joint pilot and iterative decoding carrier synchronization for the short burst transmission system

SUN Jinhua1;WANG Xuemei1;WU Xiaojun2   

  1. (1. State Key Lab. of Integrated Service Networks, Xidian Univ., Xi'an  710071, China;
    2. School of Information Engineering, Chang'an Univ., Xi'an  710064, China)
  • Received:2012-10-18 Online:2014-02-20 Published:2014-04-02
  • Contact: SUN Jinhua E-mail:jhsun@xidian.edu.cn

Abstract:

Considering the low estimation accuracy and small synchronization range of carrier synchronization algorithms in low signal to noise ratio (SNR) for short burst communication systems, a joint pilot and iterative decoding soft-output carrier synchronization algorithm is proposed. Firstly, the received pilot sequence is extracted and modulation is removed, with the modulation-removed signals made cross-correlated. Then the summation of all the correlation values is used to perform initial carrier parameters estimation. Secondly, the pilot sequence is reused with the soft-output information based on the extended Turbo decoder to obtain fine frequency and phase estimation values. Theoretical analysis and simulation results show that the coarse estimation algorithm can satisfy the requirements of the frequency estimation range and estimation accuracy, and preamble-middle pilot placement is optimal for a certain length of the data frame; The turbo decoder can obtain more reliable soft-output information with small residual frequency offset after initial coarse synchronization when the normalized frequency offset is less than 1.5×10-3, with the joint pilot and soft-output of the decoder used to estimate fine carrier parameters, which can make the turbo code achieve optimal BER performance.

Key words: synchronization, pilot, Turbo code, soft-output

CLC Number: 

  • TN911.22