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The estimation of the source number is the foundation and the prerequisite for blind source separation. Most source number estimation algorithms assume that the number of the observed signals is more than that of the source signals. However, these methods are always failed when there are more source signals than observed signals. Traditional blind signal estimation methods for this problem do not...
Interference alignment (IA) is a promising interference management technique to improve the achievable degrees of freedom (DOF) and system throughput in a K-user interference network. However, most IA schemes only focus on minimizing the interference leakage power, leading to poor performance at low to moderate SNRs. In this paper, we put forward a novel algorithm, namely, sum-rate improved interference...
Recently, coherent detection has been utilized in Brillouin optical time domain analysis (BOTDA) sensors to improve the signal-to-noise ratio (SNR) and provide a new freedom of Brillouin frequency shift (BFS) measurement through Brillouin phase shift (BPS). The generation of probe light in coherent BOTDA sensor is usually based on double sideband (DSB) phase modulation (PM), which distorts the BGS...
In communication systems with interference, the performance of traditional adaptive beamforming to search the direction of angle (DOA) of incoming desired signal degrades because of mismatch between the true array response and the assumed array response of desired signal in a receiver antenna array. In this paper, we approach the method of maximum output Signal-to-Interference-plus-Noise Ratio (SINR)...
In actual applications of inverse synthetic aperture radar (ISAR), continuous data collection may be unachievable or the collection data during some periods are missing in long coherent processing interval, so it is often difficult to obtain a well-focused image. CS based ISAR imaging yields a good performance in high SNR. However, the performance of CS based method degrades with the increase of the...
One of the prominent techniques used to mitigate the electromagnetic energy radiation (which causes interference in the signal transmission) is smart antenna. The smart antenna system remains the noticeable dynamic approach employed to develop the power output of the signal of interest in a specified direction and reduce the interfering signal power in unnecessary direction. Smart antenna system comprises...
Polarization cancellation is an effective method to improve the radar target detection performance under the main lobe interference environment. Interference suppression ratio is widely used to assessment polarization filter performance. However, the radar target detection performance is determined by the Signal Interference plus Noise Ratio (SINR). It is important to analyze the polarization filter's...
This paper presents a new algorithm to estimate the ranges of multiple targets with super-resolution in Frequency Modulated Continuous Wave (FMCW) radar systems. The proposed algorithm is based on the monopulse estimation technique. The estimation of multiple ranges is equivalent to finding multiple frequencies from noisy discrete-time observations. In multiple frequency estimation, the frequencies...
Passive THz s-SNOM (scattering-type scanning near-field optical microscope) is a powerful tool, which can reveal the weak spontaneous radiation on a sample surface (e.g., Au, GaAs, or SiC) without external light source [1, 2]. In our passive s-SNOM, an extremely sensitive CSIP (charge-sensitive infrared phototransistor [3]) detector is necessary to be operated at low temperature less than 10 K. To...
Optical frequency conversion is an essential building block of nanophotonics, whose application ranges from tunable light sources for classical on-chip communications to miniaturized telecommunications-band interfaces for quantum information science [1]. In the widely-used silicon photonics platform (including silicon nitride and silicon dioxide), a majority of reported frequency conversion experiments...
First, the paper analyzes the basic principle of the uplink MU-MIMO and gives the user matching conditions and application suggestion. Then, an estimation method of uplink MU-MIMO gain is presented based on the tests analysis. At last, the performance of uplink MU-MIMO in the current user condition is also given.
Interferometric Surface Plasmons (SPs) microscopic sensing can be used to measure the thickness or refractive index variation of nanomaterial within the order of diffraction limit in the lateral directions. However experimental results in literatures have shown the technique suffers from severely low signal to noise ratio (SNR) which limits its practical resolution and may cause failure of the technique...
It is well known that the eigen frequency (f) of a harmonic oscillator is determined by the oscillator effective mass (meff) and spring constant (keff) according to the Hook's law equation. An optical whispering gallery microcavity, when the wavelength of the injected light coincides the cavity resonance, establishes tremendous amount of light circulating along its equator. For an ultra-high quality...
Hyperspectral imagery has been applied widely in military and civilian fields. However, mixed pixels can be commonly found in this type of image due to limitation of spatial resolution. This not only influences the precision of object recognition and classification, but also becomes an obstacle for quantification analysis of the imagery content. Spectral unmixing technique is a process aiming at identifying...
It is hard to choose one appropriate sparse reconstruction algorithm from multiple existing algorithms in different occasions. Being aware of this difficulty, four typical sparse reconstruction algorithms are studied to present comprehensive performance evaluations in terms of reconstruction accuracy, super-resolution ability and noise immunity, and it is found that the BCS algorithm performs best...
Glaucoma is the leading causes of blindness, affecting an estimated 70 million individuals in the world. Because an elevated intraocular pressure (IOP) has been identified as a major risk factor, current therapies are aimed at lowering eye pressure. Consequently, monitoring of IOP is the most important tool in diagnosis and management of glaucoma. However current pressure measurement approaches have...
Amainlobe interference suppression method is proposed in this paper, which can still work when the signal of interest (SOI) is present in the training data. In this method, the iterative adaptive approach (IAA) is applied to spatial spectrum estimation at first. Then, IAA spatial spectrum is used to reconstruct the interference-plus-noise covariance matrix (INCM). Next, the eigenvector associated...
In this paper a multi-feature fusion decision algorithm based on the idea of lingering decision is proposed. Firstly, the algorithm segments the infrared images by iterative OTSU segmentation method and detects the edge by morphological processing. Then, it extracts multiple features of the ted targets on the basis of the combination of segmentation and edge result. Finally, an integrative classifier...
Most of the blind source separation (BSS) models assume that the independent sources are observed through some unknown mixing process in the absence of noise. However, the additive noise may be present in many practical applications. The bias caused by noise will limit the separation performance of the BSS algorithm. The existing modified algorithms based on quasi-whitening only can improve the signal-to-interference...
As to digital arrays, amplitude-phase inconsistency between channels has a great influence on the performance of the adaptive antenna. With regard to the imbalance of chirp signal caused by the mismatch of channels, this paper studies the characteristics of the chirp signal and adaptive filter, and proposes a method based on the LMS adaptive filtering algorithm to eliminate the amplitude-phase inconsistency...
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