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Optimal waveform design is an important technology for cognitive radar. Much effort has been focused on designing algorithms without target impulse response prediction and constant modulus constraint. In this paper, a new waveform design method is proposed, the next transmitted waveform could match the next target signature well. Since the radar systems commonly require constant modulus waveforms...
With the continuous progress of science and technology, more extensive use of electromagnetic spectrum will make environment become more and more complex. So radar should develop towards intelligent direction and combat with complex and changeable working environment. In this paper, based on the analysis of monopulse radar, we study the relationships of detection probability versus SNR under four...
In the last decade, the aeronautical authorities expressed their need to develop a new aeronautical wireless communication system. The L-band Digital Aeronautical Communication System (L-DACS) is a candidate of the future system and orthogonal frequency-division multiplexing (OFDM) will be sued for it. Meanwhile, the Distance Measuring Equipment (DME) is also working in the aeronautical L-band. In...
The data traffic is exploding dramatically, 1000-fold data traffic increase is expected in this decade. Ultra-dense heterogeneous network (HetNet) is considered as a promising track to address this challenge. In order to mitigate the severe interference between the dense deployed small cells and improve the cell edge users' performances, cluster-based spectrum allocation and coordinated multi-point...
In this article, we investigate the capacity of large-scale multiple-input multiple-output (MIMO) multiple access channels (MACs) with linear receivers in ultra dense networks (UDNs) where the number of antennas at the base station and the number of total interfering terminals approach to infinity while maintaining a fixed ratio. To study the multicell uplink capacity of a large-scale MIMO system,...
Waveform optimization for radar/sonar systems has been recently developed, especially after cognitive radar is proposed. The waveform optimization is different as a result of different tasks of radar systems. Usually, an optimized waveform just only aims at one task in most research. In this paper, an novel algorithm is proposed to generate the transmitted signal for multi-task of radar systems. The...
This paper focuses on the optimal waveform design for target detection in scenario of range-spread target. The previously published papers, which focused on optimal waveform design, assumed the target impulse response is perfect or known. However, the target impulse response used for next transmitted waveform is the previous target impulse response. The transmitted waveform designed should aim to...
Aiming to the problem of weak primary user signal detection rate in low signal-to-noise ratio environments, we propose a novel spectrum sensing method based on the principal component analysis (PCA) and random forest (RF). From the received radio signal, a set of cyclic spectrum features are first calculated, and the PCA is applied to extract the most discriminate feature vector for classification...
Massive <bold>multiple-input–multiple-output</bold> (MIMO) wireless communications refers to the idea equipping transmitters with a very large number of antennas and has been shown to potentially allow for orders of magnitude improvement in spectral and energy efficiency using relatively simple (linear) processing. In this letter, we consider a scenario that multiple links transmit in...
Using distance geometry concepts and distance geometry constraints, this paper proposes a new abundance estimation method for hyperspectral unmixing, which improves current hyperspectral unmixing algorithms in several aspects. Firstly, considering the geometric structure of dataset by the distance geometry constraint, the optimal result with least geometric deformation can be obtained. Secondly, the...
On the basis of the previous establishment of the testbed network structure for the emulated test, this paper focuses on the transmit power analysis of the practical network and the advanced testbed network for 3G/B3G systems. The advanced testbed structure was established previously by China Mobile Communication Corporation (CMCC). Theoretical analysis, system-level simulation, and outfield testing...
Device-to-Device (D2D) communication will become an important technology in future networks with the increase of the requirements of local communication services. The interference between cellular communication and D2D communication can be coordinated by proper power control and resource allocation. In this paper, we analyze the resource allocation methods for D2D communication underlaying cellular...
Traditional Nonnegative Matrix Factorization (NMF) algorithm is sensitive to the initial value when being applied to hyperspectral unmixing, because of the local minima in the objective function. In order to solve the problem, two constraints of abundance separation and smoothness are introduced into the NMF algorithm. The proposed algorithm retains the advantages of NMF, and effectively overcomes...
In practical applications, mismatches between assumed and actual array responses lead to serious degradation of SINR at the array output. In this paper, we propose robust CMA based on the quadratic constraint, which improves the output performance. The quadratic constraint on the weight can provide excellent robustness to signal steering vector mismatches and to random perturbations in sensor parameters...
We consider the problem of estimating the central direction of arrival (DOA) of a coherently distributed source. In this paper, the integral steering vector of coherently distributed source is deduced to be a Schur-Hadamard product comprising point source steering vector and a real vector. And then a blind estimator based on second order statistics is proposed to estimate the central DOA without adopting...
In practical problems, the constrained least square constant modulus algorithm (LSCMA) can suffer significant performance degradation in the presence of the slight mismatches between the actual and presumed array responses to the desired signal. In this paper, a novel robust constrained LSCMA is proposed based on explicit modeling of uncertainties in the desired signal array response. The proposed...
When adaptive arrays are applied to practical problems, the constrained LSCMA can suffer significant performance degradation in the presence of the mismatch between the actual direction of arrival (DOA) of the signal and the look direction of the beamformers. In this paper, a novel robust constrained LSCMA under signal steering vector mismatches is proposed by using a Bayesian approach, which is robust...
We consider the problem of estimating the central direction of arrival (DOA) of multiple coherently distributed sources. This problem is encountered due to the presence of local scatters in the vicinity of a transmitter or due to signals propagating through a random inhomogeneous medium. Since the integral steering vector of coherently distributed source can be deduced to be a Schur-Hadamard product...
We consider the problem of estimating the parameters-the central direction of arrival (DOA) and angular spread of a coherently distributed source. This problem is encountered due to the presence of local scatterers in the vicinity of a transmitter or due to signals propagating through a random inhomogeneous medium. Since the computational complexity of the parameter estimation is normally highly demanding,...
When the array steering vector is precisely known, adaptive beamforming is known to have resolution and interference rejection capability. However, the performance of adaptive beamforming techniques may degrade severely in the presence of mismatches between the assumed array response and the true array response. Similar types of degradation can occur when the signal array response is known exactly,...
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