在基于波束赋形(Beamforming)的无线通信系统中,使用MUSIC算法的波达方向(Direction of Arrival,DOA)估计具有良好的性能。但是,对于MUSIC算法在低信噪比下Do A估计时间和精度之间的关系,却一直未有深入研究。因此,对均匀圆阵数学模型和...在基于波束赋形(Beamforming)的无线通信系统中,使用MUSIC算法的波达方向(Direction of Arrival,DOA)估计具有良好的性能。但是,对于MUSIC算法在低信噪比下Do A估计时间和精度之间的关系,却一直未有深入研究。因此,对均匀圆阵数学模型和MUSIC算法进行分析,研究样本数量与DOA估计精度的关系。仿真结果表明,在低信噪比下,DOA估计性能下降,通过增加估计协方差矩阵的样本数量,可以提高MUSIC算法的性能。根据仿真结果,拟合发现DOA估计角度分辨率达到1度,所需样本数量和信噪比的关系服从负指数分布。展开更多
In this paper, we propose two novel efficient scheduling schemes with network coding in multi-relay wireless network to maximize the transmission efficiency. The first one uses adaptive forwarding with network coding(...In this paper, we propose two novel efficient scheduling schemes with network coding in multi-relay wireless network to maximize the transmission efficiency. The first one uses adaptive forwarding with network coding(AF-NC), in which each relay adaptively calculates the number of packets having innovative information according to the feedback from the sink. With AF-NC, duplicate packets are not sent, and the total number of time slots needed to complete transmission can be significantly reduced. The second scheme, named adaptive forwarding with network coding and retransmission(AFR-NC), combines AF-NC with automatic repeat request(ARQ) to guarantee reliable end-to-end communication with limited resource occupation. Numerical results show that compared with simple forwarding with network coding(F-NC), AF-NC has close successful delivery rate with dramatically less time slots, while AFR-NC achieves strict reliability with limited resource cost.展开更多
文摘在基于波束赋形(Beamforming)的无线通信系统中,使用MUSIC算法的波达方向(Direction of Arrival,DOA)估计具有良好的性能。但是,对于MUSIC算法在低信噪比下Do A估计时间和精度之间的关系,却一直未有深入研究。因此,对均匀圆阵数学模型和MUSIC算法进行分析,研究样本数量与DOA估计精度的关系。仿真结果表明,在低信噪比下,DOA估计性能下降,通过增加估计协方差矩阵的样本数量,可以提高MUSIC算法的性能。根据仿真结果,拟合发现DOA估计角度分辨率达到1度,所需样本数量和信噪比的关系服从负指数分布。
基金the National Natural Science Foundation of China(Nos.61102051,61221001 and 61301117)the National High Technology Research and Development Program(863)of China(Nos.2012AA011701 and 2012AA121601)+1 种基金the Shanghai Jiao Tong University Science and Technology Innovation Foundation(No.AF0300021)the Shanghai Key Laboratory Funding(No.12DZ2272600)
文摘In this paper, we propose two novel efficient scheduling schemes with network coding in multi-relay wireless network to maximize the transmission efficiency. The first one uses adaptive forwarding with network coding(AF-NC), in which each relay adaptively calculates the number of packets having innovative information according to the feedback from the sink. With AF-NC, duplicate packets are not sent, and the total number of time slots needed to complete transmission can be significantly reduced. The second scheme, named adaptive forwarding with network coding and retransmission(AFR-NC), combines AF-NC with automatic repeat request(ARQ) to guarantee reliable end-to-end communication with limited resource occupation. Numerical results show that compared with simple forwarding with network coding(F-NC), AF-NC has close successful delivery rate with dramatically less time slots, while AFR-NC achieves strict reliability with limited resource cost.
