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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.

Liu Y.,Tsinghua University | Zhang Y.,System Engineering Research Institution | Tang J.,Tsinghua University | Zhang N.,Nanjing Marine Radar Institute | Zhu W.,Tsinghua University
Conference Record - Asilomar Conference on Signals, Systems and Computers | Year: 2015

A compressive sensing based bistatic MIMO radar is proposed for joint direction of departure (DOD), direction of arrival (DOA) and Doppler frequency estimation, where random arrays are employed and the intervals between adjacent pulses are chosen randomly. A discretization mechanism for DOD- DOA-Doppler space is established. Under such a sparse framework, the least amount of random measurements required for faithful target parameter recovery is derived. The theoretical derivation indicates that a dramatic reduction in the number of measurements is attainable without degrading the estimation performance. Numerical results demonstrate the effectiveness of the framework as well as the recovery guarantees. © 2015 IEEE.

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.

Lu Q.,Nanjing Marine Radar Institute | Gui L.,Nanjing Marine Radar Institute | Shi L.,Nanjing Marine Radar Institute | Kong Y.,Nanjing Marine Radar Institute | Chen W.,Nanjing Marine Radar Institute
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2016

A dual-polarized phased array operated over 4:1 bandwidth with a maximum of ±45° scan volume is proposed, the proposed array is composed of strip-fed balanced antipodal vivaldi antenna(BAVA) element, exhibits low cross polarization and this performance is well suited for use in polarization radar. In this paper, active reflection coefficient of broadside beam is optimized by unit cell simulation for infinite array and the scan performance of the proposed finite dual-polarized phased array is thoroughly investigated using commercially available EM simulation tools. A prototype phased array consist of 32×17 horizontal elements and 33×16 vertical elements was fabricated and its measured results agree well with our simulation prediction and indicate a relatively wide-scan performance. © IEEE.

Tian T.,Nanjing Marine Radar Institute | Liu P.,Nanjing Marine Radar Institute | Kuang H.,Nanjing Marine Radar Institute
Proceedings - 2015 3rd International Conference on Advanced Cloud and Big Data, CBD 2015 | Year: 2015

Since preserving data locality is very important in MapReduce frameworks, the placement of jobs' input data becomes critical for MapReduce job performance. However, existing data placement strategies applied in MapReduce based file systems lack the efficient control of data storage. Some input data of jobs may concentrate in a few nodes, making slots contention on those nodes more aggressive and thereby hurting job performance significantly. To address this problem, we propose a Slot-Sensitive Data Placement strategy that aims to alleviate the contention for slots due to inappropriate data placement. By separately placing the input data of jobs on as many nodes as possible according to the availability of slots, SSDP contributes to the improvement of job performance. Extensive simulations by replaying public workloads demonstrate that SSDP can significantly improve the job performance up to 13%. © 2015 IEEE.

Gao G.,Nanjing Marine radar Institute | Yuan H.,Nanjing Marine radar Institute | Jian L.,Nanjing Marine radar Institute | Ma M.,China Mobile
ISAP 2013 - Proceedings of the 2013 International Symposium on Antennas and Propagation | Year: 2013

The design and development of a simple broadband patch antenna for X-band application is introduced. The antenna consist of 2 layers substrate, which can be manufactured easily. The measured bandwidth is more than 20% for voltage standing wave ratios<2. The measured radiation patterns of the 1 × 8 element linear subarray are presented and discussed in detail. It can be used as a conformal antenna. © 2013 Antenna Society of the Chinese Institute of Electronics.

Pan J.,Zhejiang University | Wang Z.,Zhejiang University | Tang S.,Nanjing Marine Radar Institute | Wang J.,Nanjing Marine Radar Institute | And 3 more authors.
Final Program and Book of Abstracts - iWAT 2011: 2011 IEEE International Workshop on Antenna Technology: Small Antennas, Novel Structures and Innovative Metamaterials | Year: 2011

In this paper, we replace low-pass filter (LPF) in traditional direct-conversion receiver (DCR) in pulse compression radar (PCR) by pre-defined filter (PDF) to directly filter direct-current offset and low frequency noise. We also accordingly propose an algorithm for compensating the distance range resolution degradation caused by PDF's effect on low frequency components of received linear frequency modulation (LFM) signals. Based on the theoretical understanding on how the low frequency band influences the pulse compression, a set of newly deduced equations are used to calculate the compression, and the range resolution degradation can be recovered based on the priori knowledge of the employed LFM signal and filters. This method can be used in all pulse compression radars where pre-defined continuous radar signals are employed. © 2011 IEEE.

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.

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.

Jian Z.,Nanjing Marine Radar Institute | Wu H.,Nanjing Marine Radar Institute | Wang H.,Nanjing Marine Radar Institute
Applied Mechanics and Materials | Year: 2011

In order to improve the case that the safety margin is a little higher using GB3480 to determine the gear root stress, a method which combines the GB3480 and FEM to determine the basic value of gear root stress is proposed. Using FEM, the comprehensive gear root stress can be figured out firstly based on the accurate tooth profile model. Then the gear root stress can be determined more accurately according to the key coefficients. Using the proposed method, the basic value of the gear root stress for the gears given in this paper is decreased by 11%. The proposed method can provide the useful guide to lightweight design for the gear transmission system. © 2011 Trans Tech Publications.

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