CBTC  DCN  RequirementsRodrigo  AlvarezSenior  ICT  Consultant

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

How  fundamental  are  Communications  to  CBTC?

CBTC  =Communications  Based Train  Control

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Data  Communications  Network  (DCN)

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Wayside  Transmission  Network

àWayside  Transmission  Network• Today  →  Gigabit  Ethernet  WAN• Future  →  Potentially  MPLS-­TP

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Wayside  Bandwidth  Requirements

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Wayside  Bandwidth  Requirements

à IXL-­OC  /  OC-­IXL 200  kb/s  – 1  Mb/sà IXL-­IXL 8  kb/sà IXL-­ZC  /  ZC-­IXL 40  kb/sà IXL-­ATS  /  ATS-­IXL 10-­20  kb/s

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Wayside  QoS Requirements

àE2E  Latency:  10-­20  msàNetwork  Recovery  Time:  50-­300  msàBit  Error  Rate:  10#$

àAvailability:  99.999%

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Network  Architecture

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Train-­to-­Wayside  Radio  Networkà ATP+ATOàWayside  Transmissionà Radio  Core(s)à Radio  Access  Networkà Onboard  Radio

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Radio  Communications  Requirements

à Train  sends  Position  Update  every  200ms  – 3sà Zone  Controller  sends  Movement  Authority  every  200ms  – 20sà Data  rate  in  the  order  of  50  kb/s  UpLink +  50-­100  kb/s  DownLinkà BUT  every  supplier  offers  a  different  proprietary  solution

PUPU

MA

PUPU

MA

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Wi-­Fi  Architecture  in  Tunnels

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Wi-­Fi  Overground  Architecture

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

LTE  Architecture  in  Tunnels

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

LTE  Architecture  Overground

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Availability

àOptions  to  support  system-­wide  99.99%  availability:• Dual  Core  architecture

• Cold/Warm/Hot  Standby• Traffic  load  sharing

• Additional  RAN  Coverage• Overlapping  Cells• Dual  Layer

Complex  Solutions,  Delivered  Simply.COMPLEX  SOLUTIONS,  DELIVERED  SIMPLY  

Mobile  Network  Architecture