Based on the analysis of decision-directed （DD） channel estimation by using training symbols, a novel DD channel estimation method is proposed for orthogonal frequency division multiplexing （OFDM） system. The prop...Based on the analysis of decision-directed （DD） channel estimation by using training symbols, a novel DD channel estimation method is proposed for orthogonal frequency division multiplexing （OFDM） system. The proposed algorithm takes the impact of decision error into account, and calculates the impact to next symbol duration channel state information. Analysis shows that the error propagation can be effectively restrained and the channel variation is tracked well. Simulation results demonstrate that both the signal error rate （SER） and the normalized mean square error （NMSE） performance of the proposed method are better than the traditional DD （DD＋ LS） and the maximum likelihood estimate （DD＋ MLE） method.展开更多
A new training symbol weighted by pseudo-noise(PN) sequence is designed and an efficient timing and fre-quency offset estimation scheme for orthogonal frequency division multiplexing(OFDM) systems is proposed. The tim...A new training symbol weighted by pseudo-noise(PN) sequence is designed and an efficient timing and fre-quency offset estimation scheme for orthogonal frequency division multiplexing(OFDM) systems is proposed. The timing synchronization is accomplished by using the piecewise symmetric conjugate of the primitive training symbol and the good autocorrelation of PN weighted factor. The frequency synchronization is finished by utilizing the training symbol whose PN weighted factor is removed after the timing synchronization. Compared with conventional schemes, the pro-posed scheme can achieve a smaller mean square error and provide a wider frequency acquisition range.展开更多
To improve frame synchronization precision, a scheme named training symbol correlation （TSC） is presented for orthogonal frequency division multiplexing （ OFDM ） system. Based on the solution from Schmidl and Cox,...To improve frame synchronization precision, a scheme named training symbol correlation （TSC） is presented for orthogonal frequency division multiplexing （ OFDM ） system. Based on the solution from Schmidl and Cox, a timing metric related to TSC scheme is put forward and examined. The specific method to select a threshold value provides more precise detection results, which can be shown by performance comparison between the two schemes through Monte Carlo simulation. Taking IEEE 802.1 la WLAN standard as an example, the proposed approach is superior to the most popular Schmidl scheme in terms of BER.展开更多
This article studies the coarse flame synchronization of orthogonal frequency division multiplexing access-time division duplex （OFDMA-TDD） systems and proposes a new method to improve coarse frame synchronization p...This article studies the coarse flame synchronization of orthogonal frequency division multiplexing access-time division duplex （OFDMA-TDD） systems and proposes a new method to improve coarse frame synchronization performance. The new method utilizes the user equipment to user equipment （UE-UE） interference, which is usually considered as a specific challenge for time division duplex （TDD） and also as implicit frame boundary information to enhance coarse frame synchronization performance. Numerical results show the synchronization performance is imoroved bv the new method.展开更多
基金Sponsored by the National "863" Program Project (2007AA01Z293)
文摘Based on the analysis of decision-directed （DD） channel estimation by using training symbols, a novel DD channel estimation method is proposed for orthogonal frequency division multiplexing （OFDM） system. The proposed algorithm takes the impact of decision error into account, and calculates the impact to next symbol duration channel state information. Analysis shows that the error propagation can be effectively restrained and the channel variation is tracked well. Simulation results demonstrate that both the signal error rate （SER） and the normalized mean square error （NMSE） performance of the proposed method are better than the traditional DD （DD＋ LS） and the maximum likelihood estimate （DD＋ MLE） method.
基金Supported by the National High Technology Research and Development Program of China ( "863" Program, No.2006AA01Z270)Natural Science Foun-dation of Shaanxi Province (No. 2007F07)+1 种基金Natural Science Foundation of Guangdong Province (No. U0635003)National "111" Program of Intro-ducing Talents of Discipline to Universities (No. B08038)
文摘A new training symbol weighted by pseudo-noise(PN) sequence is designed and an efficient timing and fre-quency offset estimation scheme for orthogonal frequency division multiplexing(OFDM) systems is proposed. The timing synchronization is accomplished by using the piecewise symmetric conjugate of the primitive training symbol and the good autocorrelation of PN weighted factor. The frequency synchronization is finished by utilizing the training symbol whose PN weighted factor is removed after the timing synchronization. Compared with conventional schemes, the pro-posed scheme can achieve a smaller mean square error and provide a wider frequency acquisition range.
文摘To improve frame synchronization precision, a scheme named training symbol correlation （TSC） is presented for orthogonal frequency division multiplexing （ OFDM ） system. Based on the solution from Schmidl and Cox, a timing metric related to TSC scheme is put forward and examined. The specific method to select a threshold value provides more precise detection results, which can be shown by performance comparison between the two schemes through Monte Carlo simulation. Taking IEEE 802.1 la WLAN standard as an example, the proposed approach is superior to the most popular Schmidl scheme in terms of BER.
文摘This article studies the coarse flame synchronization of orthogonal frequency division multiplexing access-time division duplex （OFDMA-TDD） systems and proposes a new method to improve coarse frame synchronization performance. The new method utilizes the user equipment to user equipment （UE-UE） interference, which is usually considered as a specific challenge for time division duplex （TDD） and also as implicit frame boundary information to enhance coarse frame synchronization performance. Numerical results show the synchronization performance is imoroved bv the new method.
