A carrier recovery method of the power spectrum center difference adapting to the mobile channel of the MC CDMA system with serious Doppler shift using double pilots is presented. In the transmitter, two pilots o...A carrier recovery method of the power spectrum center difference adapting to the mobile channel of the MC CDMA system with serious Doppler shift using double pilots is presented. In the transmitter, two pilots of equal frequency distance to the carrier with one putting on the left position and the other on the right position of the carrier frequency are used. Even if a continuous sine wave is transmitted, the power spectrum is expanded to a Doppler band in the receiver owing to the multi path transmission and the Doppler shift. The pilot spectrum is made to pass through two narrow band filters which are transformed to the base band with local carrier wave in the receiver. The frequency difference between the local carrier and the transmitter carrier is obtained when the difference of the gravity centers of the two pilot spectra is computed.展开更多
This paper analyzed the structure of Orthogonal Frequency Division Multiplex （OFDM） system and presented a new Carrier Frequency Offset （CFO） tracking algorithm, which depends on comparability between the decision...This paper analyzed the structure of Orthogonal Frequency Division Multiplex （OFDM） system and presented a new Carrier Frequency Offset （CFO） tracking algorithm, which depends on comparability between the decision data and the original data to correct carrier frequency offset. Therefore it is robust during the normal communization process since the Bit Error Rate （BER） of the decision data is low. We can utilize pilot data in time domain for channel estimation to track CFO without reducing system efficient and to enhance the tracking scope largely. Simulation results denote the presented algorithm can track the frequency offset and control it under ± 1% using only 1 frame if the original frequency offset is within ±8% .展开更多
基金Theworkissupportedbythenationalnaturalsciencefund! (No .6 9872 0 0 8)
文摘A carrier recovery method of the power spectrum center difference adapting to the mobile channel of the MC CDMA system with serious Doppler shift using double pilots is presented. In the transmitter, two pilots of equal frequency distance to the carrier with one putting on the left position and the other on the right position of the carrier frequency are used. Even if a continuous sine wave is transmitted, the power spectrum is expanded to a Doppler band in the receiver owing to the multi path transmission and the Doppler shift. The pilot spectrum is made to pass through two narrow band filters which are transformed to the base band with local carrier wave in the receiver. The frequency difference between the local carrier and the transmitter carrier is obtained when the difference of the gravity centers of the two pilot spectra is computed.
基金This work is supported by National Natural Science Fundation of China(60372099) , and National "863" High Technology Projects of China(2001AA123016) .
文摘This paper analyzed the structure of Orthogonal Frequency Division Multiplex （OFDM） system and presented a new Carrier Frequency Offset （CFO） tracking algorithm, which depends on comparability between the decision data and the original data to correct carrier frequency offset. Therefore it is robust during the normal communization process since the Bit Error Rate （BER） of the decision data is low. We can utilize pilot data in time domain for channel estimation to track CFO without reducing system efficient and to enhance the tracking scope largely. Simulation results denote the presented algorithm can track the frequency offset and control it under ± 1% using only 1 frame if the original frequency offset is within ±8% .
