The Research And Implement Of Carrier Frequency Offset Estimation And Channel Estimation Algorithms In Ad Hoc Network Based On 3G Technology

The carrier frequency offset estimation algorithm and channel estimation algorithm are studied and implemented in this paper. At first, the structure and features of the MANET is introduced, the communication framework and receive technique scheme are summarized. Then, according to the features of the MANET, a carrier frequency offset estimation algorithm derived from maximum likelihood (ML) principle is proposed and implemented on DSP chip as well as a channel estimation algorithm based on Midamble field. An interrupt servicing system and a data transferring system are developed and implemented based on analyzing of receive process. The debugging of the whole system is completed. Aiming at the decline of the performance of the carrier frequency offset estimation in low snr(signal-to-noise ratio), further research is devoted to the carrier frequency offset estimation algorithm in this paper. A novel semi-blind carrier frequency offset estimation algorithm is proposed. The algorithm raised the performance of the estimator through the using of the information about frequency offset in the data segment as well as the pilot segment. The solution of the estimator using diversified algorithm are given and the simulation results are presented. Elementary research on the using of the semi-blind estimator in the Ad Hoc system is carried out subsequently. Finally, the Cramer-Rao bound of the estimator isstudied thoroughly.