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Joint resource allocation with QoS provisioning in K-tier heterogeneous cellular networks

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The Journal of China Universities of Posts and telecommunications 2013年第4期20卷 15-20页

作者： WANG Yong-bin ZHANG He-li LI Yi JI Hong School of telecommunication engineering Beijing University of Posts and Telecommunications

In this paper, the joint resource allocation （RA） problem with quality of service （QoS） provisioning in downlink heterogeneous cellular networks （HCN） is studied. To fully exploit the network capacity, the HCN is modeled as a K-tier cellular network where each tier＇s base stations （BSs） have different properties. However, deploying numbers of low power nodes （LPNs） which share the same frequency band with macrocell generates severe inter-cell interference. Enhancement of system capacity is restricted for inter-cell interference. Therefore, a feasible RA scheme has to be developed to fully exploit the resource efficiency. Under the constraint of inter-cell interference, we formulate the RA problem as a mixed integer programming problem. To solve the optimization problem we develop a two-stage solution. An integer subchannel assignment algorithm and Lagrangian-based power allocation algorithm are designed. In addition, the biasing factor is also considered and the caused influence on system capacity is evaluated. Simulation results show that the proposed algorithms achieve a good tradeoff between network capacity and interference. Moreover, the average network efficiency is highly improved and the outage probability is also decreased.

关键词： heterogeneous cellular networks joint RA inter-cell interference cell range expansion

Performance of an Improved One-Way Error Reconciliation Protocol Based on Key Redistribution

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China Communications 2014年第6期11卷 63-70页

作者： ZHAO Feng LI Jingling School of Physics and telecommunication engineering Shaanxi University of Technology

In data post-processing for quantum key distribution, it is essential to have a highly efficient error reconciliation protocol. Based on the key redistribution scheme, we analyze a one-way error reconciliation protocol by data simulation. The relationship between the error correction capability and the key generation efficiency of three kinds of Hamming code are demonstrated. The simulation results indicate that when the initial error rates are （0,1.5%], （1.5,4%], and （4,11%], using the Hamming （31,26）, （15,11）, and （7,4） codes to correct the error, respectively, the key generation rate will be maximized. Based on this, we propose a modified one-way error reconciliation protocol which employs a mixed Hamming code concatenation scheme. The error correction capability and key generation rate are verified through data simulation. Using the parameters of the posterior distribution based on the tested data, a simple method for estimating the bit error rate （BER） with a given confidence interval is estimated. The simulation results show that when the initial bit error rate is 10.00%, after 7 rounds of error correction, the error bits are eliminated completely, and the key generation rate is 10.36%; the BER expectation is 2.96×10^-10, and when the confidence is 95% the corresponding BER upper limit is 2.17×10^-9. By comparison, for the single （7,4） Hamming code error reconciliation scheme at a confidence of 95%,the key generation rate is only 6.09%, while the BER expectation is 5.92x 10＂9, with a BER upper limit of 4.34×10^-8. Hence, our improved protocol is much better than the original one.

关键词： quantum key distribution error reconciliation data post-processing

PAPR reduction for FBMC-OQAM systems using P-PTS scheme

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The Journal of China Universities of Posts and telecommunications 2015年第6期22卷 78-85页

作者： Liu Kaiming Hou Jundan Zhang Peng Liu Yuan'an School of telecommunication engineering Beijing University of Posts and Telecommunications

Filter bank multi-carrier （FBMC） with offset quadrature amplitude modulation （OQAM） has been regarded as one of the candidates for next generation broadband wireless communication systems. Being a multi-carrier technique, FBMC suffers from the inherent drawback of high peak-to-average power ratio （PAPR）. And it has been turned out that conventional PAPR reduction schemes for orthogonal frequency division multiplexing （OFDM） systems are ineffective for FBMC-OQAM systems, due to the overlapping structure of FBMC-OQAM signals. In this paper, we propose an efficient PAPR reduction scheme based on a two-step optimization structure, named pretreated partial transmit sequence （P-PTS）. The first step uses a multiple overlapping symbols joint optimization scheme that the phase rotation sequences for current symbol is determined and optimized according to previous overlapped symbols. And in the second step, it employs a novel segment PAPR reduction scheme based on PTS technique. Simulation results indicate that the proposed P-PTS scheme can achieve better PAPR reduction performance than conventional methods with lower computational complexity and the complexity can be traded off more flexibly with PAPR reduction performance.

关键词： FBMC-OQAM PAPR P-PTS

Simple and spectrally-efficient design of high capacity hybrid WDM/TDM-PON with improved receiver sensitivity

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The Journal of China Universities of Posts and telecommunications 2013年第3期20卷 114-120页

作者： KHAN Ahmed Muddassir ZHANG Jie ZHAO Yong-li GAO Guan-jun CHEN Sai WANG Dao-bin School of telecommunication engineering Beijing University of Posts and Telecommunications

A simple design of hybrid wavelength division multiplexed/time division multiplexed passive optical network （WDM/ TDM-PON） is demonstrated for the high capacity next generation access （NGA） network, having advantages of both WDM and TDM based PON techniques. A 10 Gbit/s differential quadrature phase shift keying （DQPSK） data signal is used at optical line terminal （OLT） for downstream, whereas a 2.5 Gbit/s inverse return-to-zero （IRZ） data signal with high extinction ratio is used for upstream signal by intensity re-modulation of downstream signal, no additional laser is used at optical network unit （ONU）. Simulation results verify that aggregated 100 Gbit/s downstream transmissions of 10 DQPSK channels and aggregated 25 Gbit/s upstream transmission of 10 IRZ channels, using spectrally-efficient 50 GHz channel spacing, can be successfully achieved over a distance of 20 km with less than 1 dB transmission power penalties and improved receiver sensitivity.

关键词： centralized light source hybrid WDM/TDM-PON DQPSK IRZ receiver sensitivity

Cellular traffic offloading utilizing set-cover based caching in mobile social networks

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The Journal of China Universities of Posts and telecommunications 2016年第2期23卷 46-55页

作者： Bao Xuyan Zhou Xiaojin Zhang Yong Song Mei School of telecommunication engineering Beijing University of Posts and Telecommunications

To cope with the explosive data demands, offloading cellular traffic through mobile social networks（MSNs） has become a promising approach to alleviate traffic load. Indeed, the repeated data transmission results in a great deal of unnecessary traffic. Existing solutions generally adopt proactive caching and achieve traffic shifting by exploiting opportunistic contacts. The key challenge to maximize the offloading utility needs leveraging the trade-off between the offloaded traffic and the users＇ delay requirement. Since current caching scheme rarely address this challenge, in this paper, we first quantitatively interpret the offloading revenues on the cellular operator side associated with the scale of caching users, then develop a centralized caching protocol to maximize the offloading revenues, which includes the selective algorithm of caching location based on set-cover, the cached-data dissemination strategy based on multi-path routing and the cache replacement policy based on data popularity. The experimental results on real-world mobility traces show that the proposed caching protocol outperforms existing schemes in offloading scenario.

关键词： traffic offloading set cover caching mobile social networks

3D tomographic analysis of equatorial plasma bubble using GNSS-TEC data from Indonesian GNSS Network

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Earth and Planetary Physics 2025年第1期9卷 127-136页

作者： Ihsan Naufal Muafiry Prayitno Abadi Teguh N.Pratama Dyah R.Martiningrum Sri Ekawati Yuandhika GWismaya Febrylian FChabibi Gatot HPramono Research Center for Climate and Atmosphere Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia Indonesian Geospatial Information Agency(BIG) JakartaIndonesia dept.of Physics Faculty of ScienceUniversiti Teknologi MalaysiaJohor BahruMalaysia dept.Earth Planet Sci. Hokkaido UniversitySapporoJapan School of Electrical engineering Telkom UniversityBandungIndonesia

Equatorial Plasma Bubbles(EPBs)are ionospheric irregularities that take place near the magnetic *** most commonly occur after sunset during the equinox months,although they can also be observed during other *** phenomenon significantly disrupts radio wave signals essential to communication and navigation *** national network of Global Navigation Satellite System(GNSS)receivers in Indonesia(>30°longitudinal range)provides an opportunity for detailed EPB *** explore this,we conducted preliminary 3D tomography of total electron content(TEC)data captured by GNSS receivers following a geomagnetic storm on December 3,2023,when at least four EPB clusters occurred in the Southeast Asian *** and extracted TEC depletion with a 120-minute running average were then used as inputs for a 3D tomography *** 2D spatial distribution consistently captured the four EPB clusters over *** tomography results were validated through a classical checkerboard test and comparisons with other ionospheric data sources,such as the Global Ionospheric Map(GIM)and International Reference Ionosphere(IRI)*** of the results demonstrates the capability of the Indonesian GNSS network to measure peak ionospheric *** findings highlight the potential for future three-dimensional research of plasma bubbles in low-latitude regions using existing GNSS networks,with extensive longitudinal coverage.

关键词： EPB Indonesian GNSS Network 3D tomography

QoE based power control scheme for interference mitigation in high-density WLANs

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The Journal of China Universities of Posts and telecommunications 2016年第2期23卷 24-30页

作者： Wang Yiqing Wen Xiangming Hu Zhiqun Lu Zhaoming School of telecommunication engineering Beijing University of Posts and Telecommunications

Mobile data traffic is going through an explosive growth recently as mobile smart devices become more and more ubiquitous, causing huge pressure on cellular network. Taking advantage of its low cost and easy-to-deploy feature, wireless local-area networks（WLAN） becomes increasingly popular to offload data streams from cellular network, followed by higher and higher density of its deployment. However, the high density of WLAN will cause more interference, which results in degradation of its performance. Therefore, in order to enhance the performance of the network, we aim to minimize the interference caused by high density of WLAN. In this paper, we propose a novel power control scheme to achieve the above aim. We use the quality of experience（QoE） evaluation to coordinate the power of each access point（AP） and finally realize the optimization of the entire network. According to the simulation results, our scheme improves the performance of the network significantly in many aspects, including throughput and QoE.

关键词： power control high-density WLAN interference mitigation QoE

Method for determining the best frequency band for eavesdropping the display image of a PC

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The Journal of China Universities of Posts and telecommunications 2013年第4期20卷 93-98页

作者： DU Yu-lei Lü Ying-hua ZHANG Jin-ling ZHANG Nan School of telecommunication engineering Beijing University of Posts and Telecommunications

The display image of the video display unit （VDU） can be reconstructed by receiving and analyzing the unexpected electromagnetic noise emanated from a personal computer system. This fact is one of the information leakage threats in information security. Therefore, in order to choose the best frequency range for receiving the electromagnetic compromising emanations form a PC display effectively and quickly, a method based on the correlation power analysis （CPA） and the common equipments is proposed. Firstly, the frequency spectrum of 10 MHz to 1 GHz is measured about 10 times respectively when the PC is displaying the white-black vertical strips image and black image. The frequency range which contains the display information can be obtained through the CPA. And then, the special image signal is searched around the dot frequency and harmonics. If the special signal disappears when displaying the total black image, it can be judged to be the real special signal. Finally, the best receiving frequency range can be chosen by comprehensive considering the results of CPA and the signal to noise ratio （SNR） of the special image signal. In order to check the validity of the chosen frequency range, eavesdropping experiments are carried out. The results demonstrate that the selected frequency range can retrieve the higher quality image than other frequency bands.

关键词： electromagnetic secure compromising emanations CPA eavesdropping TEMPEST

Quality of forwarding-based data disseminating strategy in urban VANET

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The Journal of China Universities of Posts and telecommunications 2015年第6期22卷 1-9,50页

作者： Wang Wenjie Luo Tao School of telecommunication engineering Beijing University of Posts and Telecommunications

As for safety applications of vehicular Ad-hoc network （VANET）, many valuable broadcast protocols have been proposed nowadays, most of which are based on either senders or receivers. In fact, sender-based protocols would fall into invalidation due to high mobility of network, while receiver-based ones would generate extra delay. Combining both the advantages of the two schemes, this paper proposes an efficient and reliable broadcast protocol based on quality of forwarding （ERBPQF） of candidate nodes. In ERBPQF, a double-phase relay scheme is presented to reach fast message dissemination in the first phase and to ensure high packet delivery ratio （PDR） in the second phase. Then, considering signal fading, channel contention, queuing delay, broadcast interference and high mobility of vehicles, a new metric called quality of forwarding （QoF） for relay selection is further proposed. The simulation results show that the delay and dissemination efficiency （DE） of ERBPQF outperforms slotted-1 protocol, accompanying with the achievement of more than 95% PDR.

关键词： broadcast protocol quality of forwarding relay strategy VANET