Bell layered space-time architecture （BLAST） is a multi-antenna communication structure with high spectrum efficiency, and it has found wide applications in LANs and WLANs. However, its performance is much poorer th...Bell layered space-time architecture （BLAST） is a multi-antenna communication structure with high spectrum efficiency, and it has found wide applications in LANs and WLANs. However, its performance is much poorer than those of other space-time coding approaches. In order to improve its performance, an improved BLAST based on RAKE receiving is investigated. The new system introduces orthogonal spreading sequences （OSS） into the transmitter while retains the basic structure of BLAST. The proposed receiver suppresses interferences from other antennas by the orthogonality contained in the received signals, and extracts information from each receiving antenna by using RAKE receiving principle to construct efficient statistic decision. Simulation results show that the improved system performs well over both frequency-fiat and frequency-selective fading channels.展开更多
To enhance the resolution of parameter estimation with limited samples received by a short passive array, an iterative nonparametric algorithm for estimating the frequencies and direction-of-arrivals （DOAs） of signa...To enhance the resolution of parameter estimation with limited samples received by a short passive array, an iterative nonparametric algorithm for estimating the frequencies and direction-of-arrivals （DOAs） of signals is proposed. The cost function is constructed using 12-norm Gaussian entropy combined with an additional constraint, 12-norm constraint or linear constraint. By minimizing the cost functions in the temporal and the spatial dimensions using corresponding iteration algorithms respectively, the sparse discrete Fourier transforms （DFTs） of temporal and spatial samples are obtained to represent the extrapolated sequences with much larger sizes than the original samples. Then frequency and angle estimates are obtained by performing the traditional simple methods on the extrapolated sequences. It is shown that the proposed algorithm offers increased resolution and significantly reduced sidelobes compared with the periodogram and beamforming based methods. And it achieves high precision compared with the high-resolution method with lower computational burden. Some numerical simulations and real data processing results are presented to verify the effectiveness of the method.展开更多
文摘Bell layered space-time architecture （BLAST） is a multi-antenna communication structure with high spectrum efficiency, and it has found wide applications in LANs and WLANs. However, its performance is much poorer than those of other space-time coding approaches. In order to improve its performance, an improved BLAST based on RAKE receiving is investigated. The new system introduces orthogonal spreading sequences （OSS） into the transmitter while retains the basic structure of BLAST. The proposed receiver suppresses interferences from other antennas by the orthogonality contained in the received signals, and extracts information from each receiving antenna by using RAKE receiving principle to construct efficient statistic decision. Simulation results show that the improved system performs well over both frequency-fiat and frequency-selective fading channels.
基金supported by the Program for New Century Excellent Talents in University (NCET-06-0856)the National Natural Science Foundation of China (60772068)
文摘To enhance the resolution of parameter estimation with limited samples received by a short passive array, an iterative nonparametric algorithm for estimating the frequencies and direction-of-arrivals （DOAs） of signals is proposed. The cost function is constructed using 12-norm Gaussian entropy combined with an additional constraint, 12-norm constraint or linear constraint. By minimizing the cost functions in the temporal and the spatial dimensions using corresponding iteration algorithms respectively, the sparse discrete Fourier transforms （DFTs） of temporal and spatial samples are obtained to represent the extrapolated sequences with much larger sizes than the original samples. Then frequency and angle estimates are obtained by performing the traditional simple methods on the extrapolated sequences. It is shown that the proposed algorithm offers increased resolution and significantly reduced sidelobes compared with the periodogram and beamforming based methods. And it achieves high precision compared with the high-resolution method with lower computational burden. Some numerical simulations and real data processing results are presented to verify the effectiveness of the method.
