Current Issue : July - September Volume : 2018 Issue Number : 3 Articles : 5 Articles
Space-division multiplexing over few-mode fibers is a promising solution to increase the\ncapacity of the future generation of optical transmission systems. Mode-dependent loss (MDL) is\nknown to have a detrimental impact on the capacity of few-mode fiber systems. In the presence of\nMDL, spatial modes experience different attenuations which results in capacity reduction. In this\nwork, we propose a digital signal processing solution and an optical solution to mitigate the impact\nof MDL and improve the channel capacity. First, we show that statistical channel state information\ncan be used for a better power allocation for spatial modes instead of equal launch power to increase\nthe system capacity. Afterwards, we propose a deterministic mode scrambling strategy to efficiently\nreduces the impact of MDL and improves few-mode fiber systems capacity. This scrambling strategy\ncan be efficiently combined with the optimal power allocation to further enhance the capacity.\nThrough numerical simulations of the average and outage capacities, we show that the proposed\ntechniques bring significant capacity gains....
The last few years, many studies have been published on the 3rd-order inverse Volterra\nseries transfer function nonlinear equalizer (IVSTF-NLE) in long-haul optical communication systems.\nNonetheless, no experimental work has been published on investigating the potential of the\n3rd-order IVSTF-NLE for the compensation of Kerr nonlinearities in a long-haul wavelength division\nmultiplexing (WDM) system consisting of high-bit rate super-channels, as high as 400 Gb/s. In this\npaper, we study experimentally the performance of a 3rd-order IVSTF-NLE in a coherent optical\nWDM system, with a central, 400-Gb/s, 4-band, dual-polarization (DP), 16-ary quadrature amplitude\nmodulation (QAM) orthogonal frequency division multiplexing (OFDM) super-channel. We compare\nits performance against the performance of the digital back-propagation split-step Fourier (DBP-SSF)\nmethod for the compensation of nonlinearities after 10 Ã?â?? 100 km of ITU-T G.652 standard single\nmode fiber (SSMF). In the second part of this paper, we compare, via Monte Carlo simulations,\nthe performance of the 3rd-order IVSTF-NLE and the DBP-SSF method, in terms of reach extension\nand computational complexity, after propagation through ITU-T G.652 SSMF and a ITU-T G.655 large\neffective area fiber (LEAF). By means of both experimental evaluation and simulations, we show that,\nin the presence of strong nonlinear effects, the 3rd-order IVSTF-NLE, which uses a single step per\nspan, performs similarly with the two-steps-per-span DBP-SSF, whereas the eight-steps-per-span\nDBP-SSF is only marginally better but at the vast expense of computational complexity....
Technologies such as Bluetooth, RFID, WiFi, 4G, and the Internet of things are mutually converged with ADSL and fiber\nto the home network. Users can get information in the forms of word, voice, images, etc. through ubiquitous networks\nincluding the fixed telephone, the mobile telephone, the television, the computer, and diversified informational zed\nterminal equipment. Ubiquity informatization may be the trend of future network development, which is the development\ndirection of the ubiquitous intelligent comprehensive network information society. Its physical representation is the\nappearance of ubiquitous network or the named universal network. It represents the ubiquitous prosperity that all\npeople, all organizations, and industries can get benefits from the ubiquity informatization. This article studies the\ninternal and external structures of network service model and introduces technology dynamics, demand dynamics,\ncompetition, and security as adjustment variables. Then, the evaluation model of network service based on network\nconvergence is proposed and tested. The test results prove the validity of the evaluation model....
In the Fifth Generation (5G) wireless standard, the Internet of Things (IoT) will interconnect\nbillions of Machine Type Communications (MTC) devices. Fixed and mobile wearable devices and\nsensors are expected to contribute to the majority of IoT traffic. MTC device mobility has been\nconsidered with three speeds, namely zero (fixed) and medium and high speeds of 30 and 100 kmph.\nDifferent values for device mobility are used to simulate the impact of device mobility on MTC\ntraffic. This work demonstrates the gain of using distributed antennas on MTC traffic in terms of\nspectral efficiency and fairness among MTC devices, which affects the number of devices that can be\nsuccessfully connected. The mutual use of Distributed Base Stations (DBS) with Remote Radio Units\n(RRU) and the adoption of the millimetre wave band, particularly in the 26 GHz range, have been\nconsidered the key enabling technologies for addressing MTC traffic growth. An algorithm has been\nset to schedule this type of traffic and to show whether MTC devices completed their traffic upload\nor failed to reach the margin. The gains of the new architecture have been demonstrated in terms of\nspectral efficiency, data throughput and the fairness index....
The rapid evolution in mobile devices and communication technology has increased\nthe number of mobile device users dramatically. The mobile device\nhas replaced many other devices and is used to perform many tasks ranging\nfrom establishing a phone call to performing critical and sensitive tasks like\nmoney payments. Since the mobile device is accompanying a person most of\nhis time, it is highly probably that it includes personal and sensitive data for\nthat person. The increased use of mobile devices in daily life made mobile\nsystems an excellent target for attacks. One of the most important attacks is\nphishing attack in which an attacker tries to get the credential of the victim\nand impersonate him. In this paper, analysis of different types of phishing attacks\non mobile devices is provided. Mitigation techniquesââ?¬â?anti-phishing\ntechniquesââ?¬â?are also analyzed. Assessment of each technique and a summary\nof its advantages and disadvantages is provided. At the end, important steps to\nguard against phishing attacks are provided. The aim of the work is to put\nphishing attacks on mobile systems in light, and to make people aware of\nthese attacks and how to avoid them....
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