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Primary User Emulation (PUE) attack is one of the major concerns and problems in cognitive radio networks. Essentially, an intruder who tries to interfere and occupy the vacant spectrum of the primary user (PU) can emulate or impersonate the primary user by mimicking certain characteristics and features of the primary user signal. As a direct result, it may seem to secondary users (SUs) as though...
In a spectrally congested environment or a spectrally contested environment which often occurs in cyber security applications, multiple signals are often mixed together with significant overlap in spectrum. This makes the signal detection and parameter estimation task very challenging. In our previous work, we have demonstrated the feasibility of using a second order spectrum correlation function...
Network Function Virtualization (NFV) and Software Defined Network (SDN) are introduced to provide virtualization technology, which can tackle the deployment of network service functions in corporate networks, broadband access networks, and more recently in data centers. It is full of challenge to enhance the flexibility, efficiency and effectiveness of service function deployment. Although Service...
We present a dispersion-optimized elliptical-core few-mode fiber for broadband parametric amplification in the C-band. The asymmetric structure is beneficial to eliminate crosstalk in transmission system and degradation to parametric gain.
A microwave-photonic technique for measuring dispersion characteristics of few-mode fibers is proposed and experimentally demonstrated. This technique allows simultaneous high-precision measurement of chromatic dispersion and differential modal group delay, for the first time.
We experimentally investigate the effect of EDFA-induced pump ASE noise on cavity-soliton Kerr combs for 64-QAM transmission. We find that all comb optical carrier-to-noise ratios (OCNRs) are similar with a fixed pump OCNR and comb linewidths almost remain unchanged.
An optical sensor based on a polarization-maintaining few-mode fiber (PM-FMF) for simultaneous sensing of temperature and strain is demonstrated, for the first time. The sensor has a temperature sensitivity of about 175 pm/°C and a strain sensitivity of about 5 pm/με with an accuracy of 0.1°C and 10 με.
We demonstrate a novel all-fiber mode converter based on an axial long-period fiber grating which was inscribed in two-mode fiber using a femtosecond laser. The OAM±1,1 modes can be effectively generated using this mode converter.
In this paper, a multi-user multi-relay network with wireless energy harvesting (EH) and transferring (ET) is studied. In our system, a simultaneous two-level cooperation, i.e., information-level and energy-level cooperation is conducted for uplink data transmissions (from the users to a destination). Specifically, network coding is employed at the relays to facilitate the information-level cooperation;...
In this paper, we propose a noise suppressing chaos generator to improve the bit error rate (BER) performances for the high-order differential chaos shift keying (DCSK) systems. The presented chaos generator outputs the overlapping chaotic sequences for the information modulation, which use a buffer for temporary storage, and the stored chaotic sequence is used to modulate the information bit while...
Robot-assisted minimally invasive surgery can benefit from the automation of common, repetitive or well-defined but ergonomically difficult tasks. One such task is the scanning of a pick-up endomicroscopy probe over a complex, undulating tissue surface to enhance the effective field-of-view through video mosaicing. In this paper, the da Vinci® surgical robot, through the dVRK framework, is used for...
UHF sensor plays a very important role in UHF method. In order to overcome the shortcomings of the external GIS partial discharge (PD) detection sensor, a small quasi TEM horn antenna sensor is designed in this study. Compared with the traditional TEM horn antenna, it uses the dielectric-loading, three-dimensional microstrip and back cavity structure considering the bandwidth and gain performance,...
In an underlay cognitive radio network, the cross- channel gain from a cognitive transmitter (CT) to a primary receiver (PR) is crucial for spectrum sharing. By exploiting the relaying capability of the CT, we propose a proactive estimation scheme for the cross-channel gain. In particular, the CT proactively acts as a full-duplex amplify-and- forward (AF) relay for primary transceivers to trigger...
In cognitive radio networks, the channel gain between primary transceivers, namely, primary channel gain, is crucial for a cognitive transmitter (CT) to control the transmit power and realize spectrum sharing. To obtain the primary channel gain, a backhaul between the primary system and the CT is needed. However, the backhaul is usually unavailable in practice. To deal with this issue, the CT is enabled...
This paper aims to explore pushing service framework of the personalized learning resources in network learning platform. We use the data mining technology to acquire a series of data by combining with the content filtering push strategy and the collaborative filtering push strategy. Through the analysis of learners' registration information and browsing behavior, one can analyze learners' interest...
In underlay heterogeneous networks (HetNets), the distance between a macro base station (MBS) and a macro user (MU) is crucial for a small-cell base station (SBS) to control the interference to the MU and achieve the coexistence. To obtain the distance between the MBS and the MU, the SBS needs a backhaul link from the macro system, such that the macro system is able to transmit the information of...
Since it is challenging to position the noncooperative receiver (Rx), especially when the backward frequency band of the Rx cannot be obtained by the anchors. In this paper, we propose a novel noncooperative Rx positioning method using full-duplex relay technique, where the anchors act as full-duplex relays for the Rx. It can trigger the close-loop-power-control (CLPC) between the transmitter (Tx)...
Surface nanoscale axial photonics (SNAP) structures are created with a femtosecond laser inscription for the first time. A micron-thin inscription, introduced along the fiber axis, is characterized by the measured subnanometer-small effective fiber radius variation.
Ge/Si material combination is proposed for microresonator-based frequency combs in mid-IR. A new dispersion engineering approach is used, enabling octave-spanning mode-locked comb generation with a pump power as low as 190 mW.
We experimentally demonstrate 7-fold multicasting of 20-Gbaud QPSK signals based on Kerr frequency combs generated in a silicon nitride microresonator. The effect of high phase-noise comb state on the multicasting performance has also been studied.
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