Most subway routes in core urban areas are located deep underground, where macro cellular coverage is non-existent. In big cities worldwide, hundreds of thousands of commuters depend on the subway (or Métro, MTR, MRT, U-bahn, Underground, etc.) on a daily basis. They need dedicated wireless networks to stay connected. First responders also need reliable public safety networks in subways stations and tunnels. Subway systems are one of the most challenging environments for wireless network design.

1. IN WHAT CITY DO METRO CARS HAVE CARPET
FLOORING?
A) Beijing, China
B) Bucharest, Romania
C) Washington, D.C, USA
Subway's Wireless Network Design #iBwaveTalks

2. A) NEW YORK CITY, USA
WHAT IS THE WORLD’S LARGEST METRO
(PASSENGER-ROUTE LENGTH)?
B) SEOUL, SOUTH KOREA
C) LONDON, ENGLAND
Subway's Wireless Network Design #iBwaveTalks

3. A) 532 FT
KIEV, UKRAINE HAS THE DEEPEST METRO STATION
– HOW DEEP UNDERGROUND IS IT?
B) 187 FT
C) 346 FT
Subway's Wireless Network Design #iBwaveTalks

4. A) LONDON,ENGLAND
WHAT CITY HAS THE MOST METRO STOPS?
B) SHANGHAI, CHINA
C) NEW YORK, USA
Subway's Wireless Network Design #iBwaveTalks

5. A) 400 METERS
A TRAIN TRAVELING 100 KM/H OVERTAKES A
MOTORBIKE TRAVELING 64 KM/H IN 40 SECONDS.
HOW LONG IS THE TRAIN?
B) 1822 METERS
C) 1011 METERS
Subway's Wireless Network Design #iBwaveTalks

6. A) NEW YORK CITY, USA
WHAT CITY HAD THE WORLD’S FIRST METRO?
B) LONDON, ENGLAND
C) MOSCOW, RUSSIA
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7. A) SHANGHAI, CHINA
WHAT CITY HAS THE BUSIEST METRO SYSTEM?
B) TOKYO, JAPAN
C) MOSCOW, RUSSIA
Subway's Wireless Network Design #iBwaveTalks

8. A) 14
HOW MANY OF THE WORLD’S 180 METRO
SYSTEMS HAVE DRIVERLESS TRAINS?
B) 30
C) 46
Subway's Wireless Network Design #iBwaveTalks

9. A) MONTREAL, CANADA
WHAT CITY HAS WHAT’S CONSIDERED THE MOST
BEAUTIFUL STATIONS IN THE WORLD?
B) TOKYO, JAPAN
C) MOSCOW, RUSSIA
Subway's Wireless Network Design #iBwaveTalks

10. A) CHICAGO, USA
IN WHAT CITY ARE THERE METRO CARS RESERVED
SPECIFICALLY JUST FOR WOMEN?
B) ISTANBUL, TURKEY
C) TOKYO, JAPAN
Subway's Wireless Network Design #iBwaveTalks

11. A) 2 CENTS
HOW MUCH DID IT COST TO RIDE THE NYC
SUBWAY WHEN IT OPENED IN 1904?
B) 10 CENTS
C) 5 CENTS
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12. A) 10 CENTS
AND WHAT DID IT COST TO RIDE THE NYC
SUBWAY 44 YRS LATER, IN 1948?
B) 25 CENTS
C) 50 CENTS
Subway's Wireless Network Design #iBwaveTalks

13. A) THIRD RAIL
WHAT IS THE COMMON NAME GIVEN TO THE
SOURCE OF ELECTRICAL POWER FOR A SUBWAY
CAR?
B) SECOND RAIL
C) WHITEBOX
Subway's Wireless Network Design #iBwaveTalks

14. A) BUDAPEST, HUNGARY
IN WHAT CITY DO THE SUBWAY TRAINS RIDE ON
RUBBER WHEELS?
B) NEW YORK, USA
C) PARIS, FRANCE
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15. The webinar will begin shortly.
Join the webinar conversation on Twitter
#iBwaveTalks
PRESENTED BY:
VLADANJEVREMOVIC,PhD
RESEARCH DIRECTOR

16.  Sendus yourquestionsorcomments
 GotoWebinarQuestionsBox
 Twitter> @iBwave #iBwaveTalks
 Slides& videorecordingavailabletomorrow
tomorrow
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17. Small Cell Industry
Awards 2014
Small cell tool
design &
technology
innovation
IN-BUILDING WIRELESS 700+ CUSTOMERS 87 COUNTRIES
GLOBAL SOLUTIONS FOR IN-BUILDING NETWORK DESIGN & WIRELESS LIFECYCLE
MANAGEMENT
Subway's Wireless Network Design #iBwaveTalks

18.  Subways around the world
 Target areas for IBS coverage
 Design Requirements
 Best Practices
 3D modeling
 Tunnels
 Environmental concerns
 Capacity dimensioning
 IBS Solution
 RF Coverage maps
 Conclusion
 Q&A
Subway's Wireless Network Design #iBwaveTalks

19. BUSIEST UNDERGROUNDTRANSIT SYSTEMS
#2
2.5B
passengers
/year
#3
2.5B
passengers
/year
Tokyo Seoul Beijing Shanghai
#5
2.3B
passengers
/year
#1
3.2B
passengers
/year
#4
2.4B
passengers
/year
Moscow
SOURCE: Wikipedia
Subway'sWirelessNetwork Design #iBwaveTalks

20. #2
429
stations
#3
300
stations
NYC Seoul Paris Shanghai
#5
292
stations
#1
468
stations
#3
300
stations
Madrid
SOURCE: Wikipedia
Subway'sWirelessNetwork Design #iBwaveTalks

21. 100-150
passengers
/car
1,200
passengers
/train
36,000
passengers
/hour
80,000
passengers
/hour
MTR in Hong
Kong
Average
capacity
Record
capacity
SOURCE: Wikipedia
Subway'sWirelessNetwork Design #iBwaveTalks

22. Entry Hall
Ticket Booth Escalators Hallways Stairways
Subway's Wireless Network Design #iBwaveTalks

23. Car
Platform
TunnelTrain
Subway's Wireless Network Design #iBwaveTalks

24.  Trainstation
 GSM, UMTS,LTE, Publicsafety,WiFi
 Tunnel
 GSM, UMTS,LTE
 WiFinotrequired
 Public safetymusthavecoverageintheworstcasescenario
 Minimum IBS signal requirements:
 GSM BCCH= -85dBm
 UMTSRSCP= -85dBm
 LTE RSRP= -95dBm
 WiFiRx = -75dBm
Subway'sWirelessNetwork Design #iBwaveTalks

25. Video stream
• IBS signal propagates horizontally through platforms,but alsovertically, between platforms
• Signal overlapbetween platforms should bekept to minimum
• 3D modeling ofmultilevel train station is essential
Subway'sWirelessNetwork Design #iBwaveTalks

26. Video stream
• Traincars need IBScoverage
• Signal propagates only through windows
• Window height, length andposition is essential toassess RF coverage
• 3D models oftrains must be included at station andin tunnels
Subway'sWirelessNetwork Design #iBwaveTalks

27. • Radiating cables areoften used in tunnels, mounted at side wallat train window height
• Remote Units (RU) oreNodeB areused to feed the cable
• Pathloss example: Eupen RMC78-HLFR @1900 MHz
• 69dB couplingloss@ 2meters
• 10W RUpowerfeedingthecable(40 dBm)
• -85 dBmtargetreceivepower
• 5dBwindowpenetrationloss
• Maxcable loss:40-(-85) – 5 -69= 61dB
• @ 6.4dB loss/100meters,maxcable length= 800meters
• Two cable runs fromeach end can cover upto1.6 km
• If a tunnel is longer, then cascading RUs may be used toextend the coverage (but watch
out for ULnoise!)
Subway'sWirelessNetwork Design #iBwaveTalks

28. • If multipath delay atthe receiver is greater than expected, SINR is degraded
• 3GPP standarddefines UMTSsearch window delay settings:
• 40(20) chip delay 20/3.84Mcps=5.2 ms  1.56km
• 256(128)chip delay 33.3 ms  10km
• 2560(1280)chip delay 333 ms  100km
• Ifcascadedcable length1.5km, searchwindow= 256
• 3GPP standarddefines LTE Cycle Prefix settings
• CyclePrefix(CP)istransmissiongapbetweenOFDMsymbols
• CPdurationdefinestolerablemultipathdelay
• 5.2ms  1.56km
• 16.7ms  5km
• Ifcascadedcable length1.5km, CP=16.7ms
Subway'sWirelessNetwork Design #iBwaveTalks

29. • If radiatingcables from the opposite end oftunnel meet in the middle, UE
must hand off fromone sector toanother
• A handofftakes2-3secondstoexecute
• UE mustbeallowedmultipleattemptstohandoffbeforefailinganddropping
thecall
• Example:
• Trainspeed36km/h(10m/s)
• 10secondsisbudgetedforhandoffcompletion
 sectoroverlapis100meters
• The length ofsector overlapdepends on:
• Trainspeed
• The numberofallowedhandoffattempts
Subway'sWirelessNetwork Design #iBwaveTalks

30. Worst case scenario:
• Doubletracktunnel
• Trainsstopnexttoeach other
• Ifpublicsafetyhasone radiatingcable, thetrainneartheoppositewallmay
experienceRF coverageoutage
• In a double track tunnel, public safety radiatingcables should be installed at
both walls toinsure “worstcase” scenario coverage
• Commercial networks need not plan for “worstcase” scenario, can have
cables on one wall only
Subway'sWirelessNetwork Design #iBwaveTalks

31. Video stream
• Tunnels areoften damp, dusty andprone tofrequent but short AC
power outages
• All cable connectionsshould bewaterproofed
• Usepowerconvertertofilteroutinstabilities
• TunnelvibrationscausePIMin loosecables
• Keepin mindthatdustalsocausesPIM
• Keepantennasawayfrommetallicobjects,includingtrainroof!
• Choose equipment location with visibility andmaintenance in mind
• A smallroomaccessibleatalltimesisabetterchoice thanbigroom
accessibleonlyafterhours
• Ifrushhourcommuterscan seeIBS equipment,socan latenightvandals
Subway'sWirelessNetwork Design #iBwaveTalks

32. Video stream
Userprofiles
• User profiles must include
• Type ofservice(voice,email…)
• Venuespecificaveragecall durationperuser(mE) duringbusyhour
• Datarate
• Key assumptions:
• All listedservicesareusedbyeverysubscriberduringbusyhour
• Some subscribersmay bedeniedservicedue tonetworkcongestion
• The goal: Calculate call rejection (blocking) forevery service type
based on
• Numberofsubscribers
• Callduration& call datarate
LTE user profile
Service type mE/User kbps
Emails 50 100
Browsing 100 200
Video conf 20 600
Data Download 150 1000
Video Streaming 100 2000
Subway'sWirelessNetwork Design #iBwaveTalks

33. Video stream
How manycommuters?
• Assume the worstcase scenario:
• Two trainsateachplatform(4trainstotal)
• Each trainhas10cars
• Each car carries150passengers(limit)
• Upto1,000in shopsnearorinsideentryhall
 Totalof4*1,500+1,000= 7,000commutersatthestation
• Assume moretrains arenearby
• Twotrainsapproachingthestation
 Totalof2*1,500= 3,000commuters intunnels
• Total of 10,000 commuters need tobe supported byIBS at the station
Subway'sWirelessNetwork Design #iBwaveTalks

34. Video stream
How manysubscribers per Wireless Service Provider?
• Total of 10,000 commuters:
• WSPA: 30% penetration rate
• GSM:5%
• UMTS:35%
• LTE: 60%
• WSPB: 25% penetration rate
• GSM:5%
• UMTS:40%
• LTE: 55%
• WSPC:25% penetration rate
• GSM:5%
• UMTS:45%
• LTE: 50%
• WSPD: 20% penetration rate
• GSM:10%
• UMTS:60%
• LTE: 30 %
station tunnel station tunnel station tunnel
WSP A 105 45 735 315 1,260 540
WSP B 88 38 700 300 963 413
WSP C 88 38 788 337 875 375
WSP D 140 60 840 360 420 180
GSM UMTS LTE
Subway'sWirelessNetwork Design #iBwaveTalks

35. LTE: Establish a link between MCSefficiency and SINR
• 3GPP defines relationship between CQI,modulation andspectral efficiency
• Relationship between SINR and CQIcan be obtained from vendors or
from scientific papers
FromTS136213
Subway'sWirelessNetwork Design #iBwaveTalks

36. LTE: MCSefficiency vs. SINR
• Combining the previous twotables we get spectral efficiency vs. SINRtable forall
CQIvalues and modulation types (15 entries)
• Asimplified table with 4 entries:
• For simplicity, only the table with 4 entries is used further in this exercise
CQI Modulation MCS efficiency SINR
6 QPSK 1.18 3
9 16QAM 2.40 9
12 64QAM 3.90 15
15 64QAM 5.55 20
Subway'sWirelessNetwork Design #iBwaveTalks

37. LTE: HowmanyPhysical Resource Blocks?
• Use simplified table with 4 SINRranges
• Each SINR range has different spectral efficiency
• PRBdatarate=MCSefficiency* # ofPDSCHRE/1ms
• CalculatenumberofPRBsperserviceperSINRrange
• Example: videoconferencingneeds4PRBsinSINRRange 1
Numberof PRBs
CQI Modulation MCS efficiency SINR
6 QPSK 1.18 3
9 16QAM 2.40 9
12 64QAM 3.90 15
15 64QAM 5.55 20
Service Type Range 1 Range 2 Range 3 Range 4
Emails 1 1 1 1
Web Browsing 2 1 1 1
Video Conferencing 4 2 2 1
Data Download 6 3 2 2
Video Streaming 12 6 4 3
Subway'sWirelessNetwork Design #iBwaveTalks
LTE user profile
Service type mE/User kbps
Emails 50 100
Browsing 100 200
Video conf 20 600
Data Download 150 1000
Video Streaming 100 2000

38. LTE traffic at the station?
• Calculate SINR coverage map
• Break SINR coverage into4 SINR ranges
• WSPB:Approximately1,000LTE subscribers
• Numberof subs/range isproportionaltoSINRcoverage
• Offered traffic (E)=number of subscribers *call duration
• Total offered traffic=420 Erlangs
SINRcoverage
Metrics Range 1 Range 2 Range 3 Range 4
SNIR 3 9 15 20
Distribution 10.0% 20.0% 20.0% 50.0%
subscribers 100 200 200 500
emails 5.0 10.0 10.0 25.0
browsing 10.0 20.0 20.0 50.0
video conf 2.0 4.0 4.0 10.0
data download 15.0 30.0 30.0 75.0
video streaming 10.0 20.0 20.0 50.0
Subway'sWirelessNetwork Design #iBwaveTalks

39. Call blockage calculation
• We try to“populate” an LTE frame with PRB packets ofvarious size
• SINRrangeandminimumservicedatarateaffectthepacketsize;emailneeds1
PRB, videostreaming3-12
• The number ofavailablePRBs in LTEframe depends on RF channel size
(500 RBs in 10 MHz)
• The formula tocalculate blocking for Nconcurrent data sessions is given in
ITU-R.M. 1768-1 recommendation
rm = traffic in Erlangsfor mth dataservice
nm = numberof PRBsfor mth dataservice
Ncs = numberof differentdataservices
ITU-R call blocking
Bn = Blocking ratefornth dataservice
Subway'sWirelessNetwork Design #iBwaveTalks

40. Encounteredblocking rate
• Blockingrateiscalculatedforeach servicein eachSINRrange
• Ifaparticulardatapacketlengthcannotfitintoaframe,itisrejected/blocked
• HigherdatarateservicesrequiremorePRBsperpacketandhavegreaterblockingrate
ITU-R call blocking
Service Type Range 1 Range 2 Range 3 Range 4
Emails 2.1% 2.1% 2.1% 2.1%
Browsing 4.2% 2.1% 2.1% 2.1%
Video conf 8.3% 4.2% 4.2% 2.1%
Data Download 12.2% 6.2% 4.2% 4.2%
Video Streaming 23.5% 12.2% 8.3% 6.2%
Subway'sWirelessNetwork Design #iBwaveTalks

41. Carrieddata traffic
• Carrieddata isoffered data that is not blocked
• Carrieddata traffic (E) =(1-blocking %) *Offered traffic (E)
• Total carried traffic =398 Erlangs
• Based on Carrieddata traffic, we calculate
• compositecallblocking(5.2%)
• datausage(150GB)
• dutycycle (39.8%)
Service Type Range 1 Range 2 Range 3 Range 4
Emails 4.9 9.8 9.8 24.5
Browsing 9.6 19.6 19.6 48.9
Video conf 1.8 3.8 3.8 9.8
Data Download 13.2 28.1 28.7 71.9
Video Streaming 7.6 17.6 18.3 46.9
Subway'sWirelessNetwork Design #iBwaveTalks

42. Thekeyrequirement
• All WSPs must be included in IBS
• WSPs don’tsharesmallcells
• BuildingseparatenetworkforeachWSP isimpractical
Optimum solution: Distributed Antenna System
Video stream
Analog/Digital
Power
Amplifier
Splitters,
dividers,coax
cables
Analog/Digital Digital/ Analog
Power
Amplifier
RFSource
Passive
Active
Splitters,
dividers,coax
cables
antenna
antenna
RF/Combining
RF Source
Analog/Digital Digital/ Analog
Power
Amplifier
antenna
antenna
RFSource
RF /Combining
Subway'sWirelessNetwork Design #iBwaveTalks

43. Tunnel: GSM coverage,two trains
Subway'sWirelessNetwork Design #iBwaveTalks

44. Platform 1:GSM coverage,two trains
Subway'sWirelessNetwork Design #iBwaveTalks

45. Platform 2:GSM coverage,one train
Subway'sWirelessNetwork Design #iBwaveTalks

46. Train station, GSM coverage
Subway'sWirelessNetwork Design #iBwaveTalks

47. Train station, LTE SINR
Subway'sWirelessNetwork Design #iBwaveTalks

48. Train station, LTE MADR
Subway'sWirelessNetwork Design #iBwaveTalks

49.  Subwaysaroundthe world
 TargetareasforIBS coverage
 Design Requirements
 Best Practices
 3Dmodeling
 Tunnels
 Environmentalconcerns
 Capacitydimensioning
 IBS Solution
 RFCoveragemaps
Subway'sWirelessNetwork Design #iBwaveTalks

50. -Jointhewebinarconversation on twitter#ibwavetalks-
THANK YOU
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Contact Vladan Jevremovic,
Research Director at iBwave
vladan.jevremovic@ibwave.com