New training sequences and frame structure are proposed to estimate time-varying channel for multi-pie-input multiple-output and orthogonal frequency division multiplexing (MIMO-OFDM) systems.Thetraining sequences are...New training sequences and frame structure are proposed to estimate time-varying channel for multi-pie-input multiple-output and orthogonal frequency division multiplexing (MIMO-OFDM) systems.Thetraining sequences are modulatable orthogonal polyphase sequences,which have both good autocorrela-tions and cross-correlations.The channel impulse response (CIR) can be obtained by measuring the cor-relation between the received training sequence and the locally generated training sequence.The trainingsequences are used as guard interval instead of cyclic prefix,which not only improve the transmission ef-ficiency but also enable the channel estimator to track time-varying channel.The simulation results showthat the proposed method has about 2dB SNR gain over conventional methods in fast time-varying chan-nel.展开更多
For an odd prime p, a new sequence family of period prom- 1, size （M-1）pmr is proposed using multi-plicative and additive characters. The upper bound for the maximum magnitude of nontrivial correlations of the seque...For an odd prime p, a new sequence family of period prom- 1, size （M-1）pmr is proposed using multi-plicative and additive characters. The upper bound for the maximum magnitude of nontrivial correlations of the sequence family is derived using well-known character sums. The upper bound is shown to be （r ＋ 1）√pm ＋ 3, which meets the Welch bound asymptotically.展开更多
基金the National High Technology Research and Development Program of China(No.2006AA01Z270)the National Natural Science Foundation of China(No.60332030,60496316)
文摘New training sequences and frame structure are proposed to estimate time-varying channel for multi-pie-input multiple-output and orthogonal frequency division multiplexing (MIMO-OFDM) systems.Thetraining sequences are modulatable orthogonal polyphase sequences,which have both good autocorrela-tions and cross-correlations.The channel impulse response (CIR) can be obtained by measuring the cor-relation between the received training sequence and the locally generated training sequence.The trainingsequences are used as guard interval instead of cyclic prefix,which not only improve the transmission ef-ficiency but also enable the channel estimator to track time-varying channel.The simulation results showthat the proposed method has about 2dB SNR gain over conventional methods in fast time-varying chan-nel.
文摘For an odd prime p, a new sequence family of period prom- 1, size （M-1）pmr is proposed using multi-plicative and additive characters. The upper bound for the maximum magnitude of nontrivial correlations of the sequence family is derived using well-known character sums. The upper bound is shown to be （r ＋ 1）√pm ＋ 3, which meets the Welch bound asymptotically.
