Time filter

Source Type

Wang H.-R.,Nanjing Southeast University | Wang H.-R.,Nanjing University of Posts and Telecommunications | Wang Y.-H.,Nanjing Marine Radar Institute | Huang Y.-M.,Nanjing Southeast University | Yang L.-X.,Nanjing Southeast University
Tongxin Xuebao/Journal on Communications | Year: 2014

Two pilot contamination reduction methods in very large MIMO cellular network were proposed by dividing all cells into two types of one-dimensional very large MIMO network. The same pilot sequences were used in cells in the same category while orthogonal pilot sequences were used between these two categorie. Then the pilot power control method can be used to achieve the purpose of alleviating pilot contamination. By coordinating among base stations, the nearly optimal length of pilot sequences and assignment of pilot transmission could be found through minimizing the sum of channel estimation mean square error of all base stations. Thus, much better performance of channel estimation could be obtained, greatly enhancing the sum rate in downlink in all cells. Source

Zhou T.,Harbin Engineering University | Zhang B.-Z.,Nanjing Marine Radar Institute | Du W.-D.,Harbin Engineering University | Peng D.-D.,Harbin Engineering University
Tongxin Xuebao/Journal on Communications | Year: 2014

A new constant beamwidth time-domain beamformer based on Farrow structure filter was proposed, which consists of a digital delay unit to achieve time delay of integral times sampling interval, a high-precision fractional delay filter unit implemented by Farrow structure, and an amplitude weighing unit to ensure constant beamwidth. First, principles, features and advantages of the proposed beamformer was analyzed theoretically. Then its validity and superiority was proved via computer simulation. Finally, its good efficiency and practicability in realtime implementation was tested on C6748 DSP. Source

Zhang N.,Nanjing Marine Radar Institute | Song H.,Nanjing Marine Radar Institute | Tang J.,Tsinghua University | Shen Y.,Tsinghua University
2015 10th International Conference on Information, Communications and Signal Processing, ICICS 2015 | Year: 2015

Optimized power allocation among the transmitters in MIMO radar networks has a potential to conserve a significant amount of energy without loss of target-estimation performance. In this paper, we develop power allocation strategies for joint target position and velocity estimation in a distributed MIMO radar network. Transmitting power optimization algorithms are proposed for predetermined parameter estimation accuracy requirements in terms of the equivalent Fisher information matrix (EFIM). These algorithms aim to minimize the power budget while guaranteeing the estimation accuracy with or without the presence of parameter uncertainties. Numerical results show that the proposed algorithms can achieve appreciable energy savings. © 2015 IEEE. Source

Chen W.-J.,University of Electronic Science and Technology of China | Chen W.-J.,Nanjing Marine Radar Institute | Wang J.,Nanjing Marine Radar Institute | Nie Z.-P.,University of Electronic Science and Technology of China
Tien Tzu Hsueh Pao/Acta Electronica Sinica | Year: 2013

A simple and practical method for the calibration of digital array's receiving channels is proposed. Theoretical analysis demonstrates that the LFM signal of zero intermediate frequency synchronization among the different receiving channels of an antenna depends on their phase and time calibration. The phase calibration of a wideband LFM signal in receiving channels can be converted into the calibration of a single frequency's. The method of its amplitude calibration and the required measurment precision of the relative delays for receiving channels calibration are also derived. A wideband beamforming procedure is developed by using pulse compression based on channels calibration. The experimental results prove that the method is effective. Source

Qiao D.L.,Nanjing Marine Radar Institute | Qiao D.L.,Nanjing University | Xue F.,Nanjing Marine Radar Institute | Yang Y.,China University of Mining and Technology
Computing, Control, Information and Education Engineering - Proceedings of the 2015 2nd International Conference on Computer, Intelligent and Education Technology, CICET 2015 | Year: 2015

For a large number of clustering routing protocols are under the condition that every cluster head can communicate with sink node directly which will not happen in practice, this paper proposed an energy- saving hybrid ad-hoc routing protocol (ESHARP) for wireless sensor network. The protocol enhances the function of Heed and Direct Diffusion by combining them together. During the hierarchical characteristic, the protocol can support fast routing set-up, date aggregation; for the multi-hop communication between cluster heads and sink node, the protocol can reduce the energy consumption of the cluster heads which can make the network service time become longer consequently. © 2015 Taylor & Francis Group, London. Source

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