Beijing University of Posts and Telecommunications

About: Beijing University of Posts and Telecommunications is a education organization based out in Beijing, Beijing, China. It is known for research contribution in the topics: MIMO & Quality of service. The organization has 39576 authors who have published 41525 publications receiving 403759 citations. The organization is also known as: BUPT.

High-resolution optical spectroscopy using multimode interference in a compact tapered fibre.

Abstract: Optical spectroscopy is a fundamental tool in numerous areas of science and technology. Much effort has focused on miniaturizing spectrometers, but thus far at the cost of spectral resolution and broad operating range. Here we describe a compact spectrometer that achieves both high spectral resolution and broad bandwidth. The device relies on imaging multimode interference from leaky modes along a multimode tapered optical fibre, resulting in spectrally distinguishable spatial patterns over a wide range of wavelengths from 500 to 1,600 nm. This tapered fibre multimode interference spectrometer achieves a spectral resolution down to 40 pm in the visible spectrum and 10 pm in the near-infrared spectrum (corresponding to resolving powers of 104–105). Multimode interference spectroscopy is suitable in a variety of device geometries, including planar waveguides in a broad range of transparent materials. While desirable for compact solutions, the miniaturization of spectrometers comes at the cost of spectral resolution and operating range. Here, Wanet al. propose a tapered fibre multimode interference spectrometer exhibiting high spectral resolution from the visible to the near infrared in a compact configuration.

All optical XOR logic gates: technologies and experiment demonstrations

Abstract: This article reviews the current status and technologies of all-optical XOR gates. Various schemes with semiconductor optical amplifiers, particularly those associated with interferometric structures, are discussed and compared. Finally, the applications of all-optical XOR gates to emerging networks are explored, and the future direction is outlined.

Physical-Layer Authentication Based on Extreme Learning Machine

Abstract: Most physical-layer authentication techniques use hypothesis tests to compare the radio channel information with the channel record of Alice to detect spoofer Eve in wireless networks. However, the test threshold in the hypothesis test is not always available, especially in dynamic networks. In this letter, we propose a physical-layer authentication scheme based on extreme learning machine that exploit multi-dimensional characters of radio channels and use the training data generated from the spoofing model to improve the spoofing detection accuracy. Simulation results show that our proposed technique can significantly improve the authentication accuracy compared with the state-of-the-art method.

Signalling Cost Evaluation of Handover Management Schemes in LTE-Advanced Femtocell

Abstract: Femtocell is a small access point using the wire broadband connections or wireless technologies to access the mobile operator's network for the user equipment(UE), which can provide better indoor coverage and satisfy the upcoming demand of high data rate for wireless communication system.Femtocell related handover cost reduction is one of the important targets in LTE-Advanced SON (Self-Organising Networks). In this paper, a handover optimization algorithm based on the UE's mobility state is proposed. An analytical model was presented for the handover signalling cost analysis. Numerical results are provided to compare the signalling cost of different handover management schemes. The comparison between the proposed algorithm and the traditional handover control algorithm shows that the algorithms proposed in this paper have a significant reduction in the signalling overhead.