Mobility Control of LTE-R for Enhanced Safety of Automated High-speed Railway Control

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dc.contributor.advisor조영종, 강경란-
dc.contributor.author방준호-
dc.date.accessioned2019-04-01T16:42:15Z-
dc.date.available2019-04-01T16:42:15Z-
dc.date.issued2019-02-
dc.identifier.other28792-
dc.identifier.urihttps://dspace.ajou.ac.kr/handle/2018.oak/15199-
dc.description학위논문(박사)--아주대학교 일반대학원 :컴퓨터공학과,2019. 2-
dc.description.tableofcontentsChapter I Introduction 1 Chapter II Background 4 II.A Network based automatic HSR control system 4 II.B Requirement of LTE-R 8 II.C LTE-R mobility control 9 II.C.1 Inactive mobile station 11 II.C.2 Active mobile station 13 II.D Problems of LTE-R mobility control 16 II.D.1 Risk of degraded railway control by LTE signaling attack 17 II.D.2 Interruption of railway control by inappropriate LTE-R handover decision 18 Chapter III Machine-learning based Anomaly Detection for Alleviating Risk of Degraded Railway Control by LTE-R Signaling Attack 21 III.A LTE signaling attack 22 III.B Related work 23 III.C Overview 26 III.D Mathematical model for wakeup packet generation 31 III.E Proposed signaling attack detection algorithm 37 III.F Simulation Results 40 III.F.1 Simulation setup 40 III.F.2 Results 42 III.G Chapter summary 53 Chapter IV Machine Learning Based Handover Initiation for Seamless Train Control 54 IV.A Inappropriate handover decision of LTE-R 55 IV.B Related work 57 IV.C Overview 59 IV.D Mathematical model for cell boundary crossing time prediction 62 IV.D.1 Why Bayesian Regression Model 63 IV.D.2 Bayesian regression model selection 67 IV.D.3 Gaussian regression based RCDT prediction 73 IV.E Proposed handover decision algorithm 75 IV.E.1 Algorithm description 75 IV.E.2 Analysis on computation complexity 81 IV.F Simulation Results 83 IV.F.1 Simulation Setup 83 IV.F.2 Results 85 IV.G Chapter summary 95 Chapter V Conclusions 97 Bibliography 100-
dc.language.isoeng-
dc.publisherThe Graduate School, Ajou University-
dc.rights아주대학교 논문은 저작권에 의해 보호받습니다.-
dc.titleMobility Control of LTE-R for Enhanced Safety of Automated High-speed Railway Control-
dc.title.alternativeBang June-ho-
dc.typeThesis-
dc.contributor.affiliation아주대학교 일반대학원-
dc.contributor.alternativeNameBang June-ho-
dc.contributor.department일반대학원 컴퓨터공학과-
dc.date.awarded2019. 2-
dc.description.degreeDoctoral-
dc.identifier.localId905161-
dc.identifier.uciI804:41038-000000028792-
dc.identifier.urlhttp://dcoll.ajou.ac.kr:9080/dcollection/common/orgView/000000028792-
dc.description.alternativeAbstractThis thesis targets enhanced reliability of LTE-R wireless networks for automatic HSR control. In a typical railway control system, numerous control entities are cooperating to maintain safe and efficient railway transportation service by message exchanges. Control servers understands overall railway status by measurement data sent from sensor nodes dispersed along railways. On the other hand, the control servers send command packets to actuators dispersed along the railways as well. The actuators yield physical effects. To provide connectivity for sensor and actuators dispersed in broad area, LTE-R functions as a wayside access network, and LTE-R is again connected to a wired network where the control servers reside in. As a result, the wayside devices can communicate with the control servers only through LTE-R. Therefore, safe railway transportation service depends on reliable operation of LTE-R’s data delivery service. Current LTE-R inherits most of its technical features from general LTE including mobility control. Because of its advantages in high reliability, efficiency in bandwidth utilization, stable connectivity, general LTE is widely accepted as wireless access network for voice, video, and data services. However, merely inheriting technical features from LTE to LTE-R is problematic since railway environment is different from the environment assumed in the general LTE. This thesis analyzes problems of LTE-R’s mobility control and tries to resolve the problems with machine learning algorithms. The first problem is vulnerability of the LTE-R to signaling attack. LTE-R signaling attack seeks to consume abundant amount of resource of control plane of LTE-R exploiting vulnerability of mobility control mechanism. Signaling attack leads to degenerate quality of LTE-R’s data communication. As a result, real-time railway control becomes unavailable. This thesis proposes an LTE-R signaling attack detection scheme based on traffic modeling by Hidden semi-Markov Model which is a machine learning algorithm. It is verified by simulation results that the proposed scheme outperforms a current scheme with more accurate detection. The second problem is inadequate handover decision algorithm by LTE-R. For a train, a mobile relay relays data communication between a wayside access point, called DeNB, and an onboard steering device, train controller. Handover decision algorithm in general LTE holds handover initiation for a mobile station until the mobile station has resided in non-serving DeNB. Since mobile relays on a train moves with high-speed, the standard handover decision algorithm would make mobile relay retain week wireless connection. Thus, the mobile relay’s should relay data packets with week wireless signal when the mobile relay is moving around cell boundaries, and the reliable communication for train controllers become unable to guaranteed. This thesis proposes a handover decision algorithm for LTE-R based on a machine learning algorithm, Bayesian regression. With simulation results, this thesis verifies that the proposed scheme achieves stronger signal strength for mobile relays and enhanced packet delivery ratio as well.-
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Graduate School of Ajou University > Department of Computer Engineering > 4. Theses(Ph.D)
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