In this paper, orthogonal/turbo-codes for mobile DS-CDMA communications are considered. We compare the performances of turbo-codes with those of convolutional codes for noncoherent M-ary orthogonal modulation in ...In this paper, orthogonal/turbo-codes for mobile DS-CDMA communications are considered. We compare the performances of turbo-codes with those of convolutional codes for noncoherent M-ary orthogonal modulation in multipath fading channels. One method to calculate the branch transition probability of turbo-codes is suggested.By using the parameter of cut-off rate capacity efficiency, 1/2/5 (37,21) turbo-codes are more efficient for 1/3/9(557,663,711) convolutional codes. Given the same spread gain, turbo-codes will increase system's capacity.If SOVA is used in the decoding for turbo-codes case, the dime-delay caused by turbo-decoding is only 1.2 times of that of convolutional codes. Obviously, turbo-codes show better performances at the cost of the hardware complexity of the encoder and the decoder.展开更多
This poper presents a new method of estimating and correcting Doppler frequency shift in anM-ary (D)PSK receiver. The performance is discussed. Analytical and simulation results are presentedand the error probability ...This poper presents a new method of estimating and correcting Doppler frequency shift in anM-ary (D)PSK receiver. The performance is discussed. Analytical and simulation results are presentedand the error probability performance of the (D)PSK receiver is evaluated in the presence of the Doppler correction. It is shown from analytical and simulation results for constant Doppler shift that the methodperforms excellently.展开更多
文摘In this paper, orthogonal/turbo-codes for mobile DS-CDMA communications are considered. We compare the performances of turbo-codes with those of convolutional codes for noncoherent M-ary orthogonal modulation in multipath fading channels. One method to calculate the branch transition probability of turbo-codes is suggested.By using the parameter of cut-off rate capacity efficiency, 1/2/5 (37,21) turbo-codes are more efficient for 1/3/9(557,663,711) convolutional codes. Given the same spread gain, turbo-codes will increase system's capacity.If SOVA is used in the decoding for turbo-codes case, the dime-delay caused by turbo-decoding is only 1.2 times of that of convolutional codes. Obviously, turbo-codes show better performances at the cost of the hardware complexity of the encoder and the decoder.
文摘This poper presents a new method of estimating and correcting Doppler frequency shift in anM-ary (D)PSK receiver. The performance is discussed. Analytical and simulation results are presentedand the error probability performance of the (D)PSK receiver is evaluated in the presence of the Doppler correction. It is shown from analytical and simulation results for constant Doppler shift that the methodperforms excellently.
