The sparse signal recovery-based direction of arrival (DOA) estimation has received a great deal of attention over the past decade. From the sparse representation point of view, $$\ell _0$$ -norm is the best choice to...
The sparse signal recovery-based direction of arrival (DOA) estimation has received a great deal of attention over the past decade. From the sparse representation point of view, $$\ell _0$$ -norm is the best choice to evaluate the sparsity of a vector. However, solving an $$\ell _0$$ -norm minimization problem is non-deterministic polynomial hard (NP-hard). Thus, The common idea for many sparse DOA estimation methods is to use the $$\ell _1$$ -norm as the sparsity metric. However, its sparse solution may not coincide with the solution resulting from the $$\ell _0$$ -norm thus deteriorating the DOA estimation performance. In this paper, we propose a new sparse method based on $$\ell _p$$ ( $$0<1$$ ) regularization for DOA estimation to achieve a sparser solution than $$\ell _1$$ regularization. In particular, we use the Taylor expansion to convert the $$\ell _p$$ -norm minimization problem to a weighted $$\ell _1$$ -norm problem. Then, a two-step iterative method is employed to achieve the DOA estimate. The $$\ell _p$$ ( $$0<1$$ ) regularization is able to improve the angle resolution, leading to an improved performance in low SNR and correlated signal scenarios. Numerical results show that our proposed method has better estimation performance than many other methods do.
Reference-frame-independent quantum key distribution (RFI QKD) can generate secret keys without the alignment of reference frames, which is very robust in real-life implementations of QKD systems. However, the perfo...
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Reference-frame-independent quantum key distribution (RFI QKD) can generate secret keys without the alignment of reference frames, which is very robust in real-life implementations of QKD systems. However, the performance of decoy-state RFI QKD with both source errors and statistical fluctuations is still missing until now. In this paper, we investigate the performance of decoy-state RFI QKD in practical scenarios with two kinds of light sources, the heralded single photon source (HSPS) and the weak coherent source (WCS), and also give clear comparison results of decoy-state RFI QKD with WCS and HSPS. Simulation results show that the secret key rates of decoy-state RFI QKD with WCS are higher than those with HSPS in short distance range, but the secret key rates of RFI QKD with HSPS outperform those with WCS in long distance range.
This work conducts the secrecy analysis of full-duplex power-splitting simultaneous wireless information and power transfer networks with artificial noise. The exact closed-form expressions of the COP, SOP and RSP are...
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ISBN:
(纸本)9789811136719
This work conducts the secrecy analysis of full-duplex power-splitting simultaneous wireless information and power transfer networks with artificial noise. The exact closed-form expressions of the COP, SOP and RSP are derived, respectively, which are illustrated by numerical analysis. The results depict the significance of the power-splitting ratio and the transmit signal-to-noise ratio (SNR). To be specific, the secrecy performance is greatly improved with the increasing of the power-splitting ratio. In addition, it is observed that the security of the system will get enhanced with the increasing of the power-splitting ratio at first and then get reversed for a certain transmit SNR. Moreover, the value of the optimum transmit SNR changes with different transmit SNR.
It is shown that orbital angular momentum(OAM) is a promising new resource in future classical and quantum communications. However, the separation of OAM modes is still a big challenge. In this paper, we propose a sim...
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It is shown that orbital angular momentum(OAM) is a promising new resource in future classical and quantum communications. However, the separation of OAM modes is still a big challenge. In this paper, we propose a simple and efficient separation method with a radial varying phase. In the method, specific radial varying phases are designed and modulated for different OAM modes. The resultant beam is focused to the spots with different horizontal and vertical positions after a convex lens, when the coordinate transformation, including two optical elements with coordinate transformation phase and correct phase, operates on the received *** horizontal position of the spot is determined by the vortex phases, and the vertical position of the spot is dependent on the radial varying phases. The simulation and experimental results show that the proposed method is feasible both for separation of two OAM modes and separation of three OAM modes. The proposed separation method is availab.e in principle for any neighboring OAM modes because the radial varying phase is controlled. Additionally, no extra instruments are introduced, and there is no diffraction and narrowing process limitation for the separation.
We present a simple method on the generation of any bi-photon superposition state using only linear *** this scheme, the input states, a two-mode squeezed state and a bi-photon state, meet on a beam-splitter and the o...
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We present a simple method on the generation of any bi-photon superposition state using only linear *** this scheme, the input states, a two-mode squeezed state and a bi-photon state, meet on a beam-splitter and the output states are post-selected with two threshold single-photon detectors. We carry out corresponding numerical simulations by accounting for practical experimental conditions, calculating both the Wigner function and the state fidelity of those generated bi-photon superposition states. Our simulation results demonstrate that not only distinct nonclassical characteristics but also very high state fidelities can be achieved even under imperfect experimental conditions.
It is known that there exist two kinds of methods for direction-of-arrival (DOA) estimation in the literature: the subspace-based method and the sparsity-based method. However, pervious works reveal that the former me...
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Analyzing the influence on traffic flow at intersection according to the driving characteristics of modern tram with different lane layout types. Proposing a method of dynamic priority algorithm (DPA) based on the ide...
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As a power and bandwidth efficient modulation scheme, the optical spatial modulation (SM) technique has recently drawn increased attention in the field of visible light communications (VLC). To guarantee the number of...
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Cloud computing plays a significant role in big data era since it can provide dynamic, scalab.e virtual resource services via the Internet. However, how to enhance the security level of cloud computing is a challengin...
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ISBN:
(纸本)9781509045006
Cloud computing plays a significant role in big data era since it can provide dynamic, scalab.e virtual resource services via the Internet. However, how to enhance the security level of cloud computing is a challenging issue which is urgently to be tackled. In this paper, we center on the data security in cloud computing and present an attribute based proxy re-encryption scheme with keyword search (ABPRE-KS) to provide flexible and secure data sharing among users in the cloud. In our scheme, a user's access privileges are described by an access structure consisting of several attributes while ciphertexts are lab.led by several target attributes. A delegator can transform the original ciphertexts into proxy ciphertexts encrypted by the delegatee's attributes without leaking any sensitive information to the cloud server. Besides, a search request on the ciphertexts is allowed by a delegatee if his credentials satisfy the delegatee's access policy. By security analysis, our ABPRE-KS is confidential and keyword semantic secure under BDBH assumption.
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