vii
List of Figures
Figure1.1 Train signaling system using wayside signals ....................................2
Figure1.2 Prole-based train control system ....................................................4
Figure1.3 CBTC system...................................................................................4
Figure1.4 Typical architecture of a modern CBTC system ...............................6
Figure3.1 Superstructure subsection ..............................................................47
Figure3.2 Typical crack propagation in the head area of rail ..........................48
Figure3.3 (a) Broken rail, (b) examples of severe loss of rail foot due
tosevere corrosion, and (c) shelling ................................................48
Figure3.4 (a) Common rigid and (b) elastic fastening ....................................50
Figure3.5 Manual rail inspections expose maintenance personnel to
dangers from passing trains, ying ballast, and projectiles .............51
Figure3.6 Coverage of train-mounted and walking stick probes (a),
geometrical limitations on the current ultrasonic inspection (b),
and example of a rail break due to small rail foot defect (c) ............ 53
Figure3.7 Transducer mounting for rail foot inspection ................................. 55
Figure4.1 Measurement equipment used in the real eld CBTC channel
measurements ................................................................................68
Figure4.2 Tunnel section and deployment of antennas in the
measurement ............................................................................69
Figure4.3 (a) Tunnel where we performed the measurements in
BeijingSubway Changping Line. (b) Shark-n antenna located
on the measurement vehicle. (c) Yagi antenna. (d)APset on
the wall ..........................................................................................70
Figure4.4 Frequencies of AICc selecting a candidate distribution ..................75
viii ◾ List of Figures
Figure4.5 Simulation results generated from the FSMC model
andexperimental results from real eld measurements ..................78
Figure4.6 MSE between the FSMC model and the experimental data
with four states and eight states......................................................78
Figure 5.1 Leaky waveguide applied in viaduct scenarios of Beijing
Subway Yizhuang Line ...................................................................83
Figure5.2 Measurement equipment used in the CBTC channel
measurements ............................................................................... 84
Figure5.3 Measurement scenario ................................................................... 84
Figure5.4 Simulation results of the equivalent method and the tting
lines of several measurements .........................................................87
Figure5.5 Relative frequencies of AICc selecting a candidate distribution
as the best t to the distribution of small-scale fading amplitudes ...89
Figure5.6 Sample empirical CDFs of the small-scale fading amplitudes
and their theoretical model ts ......................................................89
Figure5.7 Variance of μ
dB
and σ
dB
with dierent receiving points ................. 90
Figure6.1 CBTC system ................................................................................96
Figure6.2 First proposed data communication system with redundancy
and no backup link ........................................................................98
Figure6.3 Second proposed data communication system with
redundancy and backup link..........................................................99
Figure6.4 CTMC model for the data communication system with basic
conguration ...............................................................................100
Figure6.5 CTMC model for the rst proposed data communication
system with redundancy and no backup link ...............................100
Figure 6.6 CTMC model for the rst proposed data communication
system with redundancy and backup link ....................................102
Figure6.7 DSPN model for the data communication system with basic
conguration ...............................................................................104
Figure6.8 DSPN model for the data communication system with
redundancy and no backup link...................................................105
Figure6.9 DSPN model for the proposed data communication system
with redundancy and backup link ................................................105
List of Figures ◾ ix
Figure6.10 Comparison of CTMC and DSPN model solutions for
dierent redundancy congurations ..........................................111
Figure6.11 Unavailability of the three WLAN-based data
communication systems .............................................................112
Figure7.1 Impacts of wireless communications on CBTC eciency ..........120
Figure7.2 Trip error under dierent hando communication latencies ......121
Figure7.3 Proposed CBTC system with CoMP ..........................................122
Figure7.4 Train control model ....................................................................123
Figure7.5 Optimal train guidance trajectory ..............................................137
Figure7.6 Control performance H
2
norm in dierent schemes ...................141
Figure7.7 Train travel trajectory in the proposed CBTC system
withCoMP ................................................................................142
Figure7.8 Train travel trajectory in the existing CBTC system...................142
Figure7.9 Train travel time error in dierent schemes ................................143
Figure7.10 Hando policies in dierent schemes .........................................144
Figure7.11 Average service discontinuity time duration in dierent
schemes.......................................................................................145
Figure8.1 WLAN hando timing diagram ................................................152
Figure8.2 Proposed hando scheme ...........................................................156
Figure8.3 FER of dierent transmission schemes .......................................159
Figure8.4 Delay dierence between adjacent APs ......................................160
Figure8.5 Latency performance improvements of the MAHO scheme ......168
Figure8.6 Time interval between two hando procedures, v=80km/h ...169
Figure8.7 (a) FER at 6.5Mbps. (b) FER at 13Mbps. (c) FER at
26Mbps. (d) FER at 65Mbps with dierent coverage areas ......170
Figure8.8 Maximum inter-site distance to meet the HO FER ...................173
Figure9.1 Train following model ................................................................181
Figure9.2 Communication procedure between ZC and the running
trains with packet drops ............................................................. 181
Figure9.3 Model of system to control a group of trains in CBTC ..............182
x ◾ List of Figures
Figure9.4 Equivalent networked control system ......................................... 183
Figure9.5 FER at certain train speeds ........................................................186
Figure9.6 Probabilities that the received power at a given distance
exceeds certain levels ..................................................................190
Figure9.7 Overlapping coverage area of APs...............................................191
Figure9.8 Field test results on handover time .............................................192
Figure9.9 Performances of T1 and T2 using the Sv scheme, T=0.3 s,
PP
k
i
k
i
(0)( 0)
0.01
γθ== ==
......................................................205
Figure9.10 Performances of T3 using the Sv scheme, T=0.3s,
PP
k
i
k
i
(0)( 0)
0.01
γθ== ==
......................................................205
Figure9.11 Performances of T3 using the Lv_d scheme, T=0.3 s,
PP
k
i
k
i
(0)( 0)
0.01
γθ== ==
..................................................... 206
Figure9.12 Performances of T3 using the Lv_f scheme, T=0.3 s,
k
i
k
i
(0)( 0)
γθ== == ..................................................... 206
Figure9.13 Performances of T3 using the Sv scheme, T=0.3 s,
PP
k
i
k
i
(0)( 0)
0.1
γθ== ==
.......................................................207
Figure9.14 Performances of T3 using the Lv_d scheme, T=0.3 s,
PP
k
i
k
i
(0)( 0)
0.1
γθ== == .......................................................207
Figure9.15 Performances of T3 using the Lv_f scheme, T=0.3 s,
PP
k
i
k
i
(0)( 0)
0.1
γθ== == ...................................................... 208
Figure9.16 Cost of T3 using the Sv, Lv_f, and Lv_d schemes,
respectively, T=0.3 s,
PP
k
i
k
i
(0)( 0) 0.1, 0.01γθ== ==
..........209
Figure 9.17 Total cost of T3 using the Sv, Lv_f, and Lv_d schemes,
respectively, T=0.3 s,
PP
k
i
k
i
(0)( 0) 0.1γθ== == ...................209
Figure10.1 Basic schematic structure of a cognitive control system .............. 216
Figure10.2 Basic procedure of a cognitive control system.............................217
Figure10.3 RL model ................................................................................... 219
Figure10.4 Schematic structure of the cognitive control approach to
CBTC systems ......................................................................... 222
Figure10.5 RL model in the cognitive control approach ..............................225
Figure10.6 Basic WLAN hando procedure. .............................................. 228
List of Figures ◾ xi
Figure10.7 (a) Tunnel where we performed the measurements.
(b)Shark-n antenna located on the measurement vehicle.
(c) Yagi antenna. (d) AP set on the wall ................................... 234
Figure10.8 (a) Cost function J at each communication cycle
underthegreedy policy and the proposed cognitive
controlpolicy. (b)e cost function J at each
communication cycle under the SMDP policy, and the
proposed cognitive control policy .............................................236
Figure10.9 Train travel trajectory under the greedy policy
(theheadwayis15s) ..............................................................237
Figure10.10 Train travel trajectory under the SMDP policy
(theheadwayis 15s) .................................................................237
Figure10.11 Train travel trajectory under the proposed cognitive
controlpolicy (the headway is 15s). ..........................................238
Figure10.12 Train travel trajectory under the proposed cognitive
controlpolicy (the headway is 90s) ..........................................238
Figure10.13 Train travel trajectory under the SMDP policy
(theheadwayis 90s) ................................................................239
Figure10.14 Train travel trajectory under the greedy policy
(theheadwayis 90s) .................................................................239
Figure10.15 Hando latency under dierent policies ...................................240
Figure10.16 Train–ground failure rate under dierent policies ....................241
Figure10.17 Performance of optimization versus steps .................................243
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