Mobility 101 You too can spew TLAs like a pro March 2012 Rajaram Pejaver [email protected] Note: The views presented here are solely those of the author.
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Evolution of Mobile Networks The Secret Terminology Basic Network Architecture Various Cell Phone Standards IMS (IP Multimedia Subsystem) Challenges in a Mobile Networks Questions
Outline
•Blah blah•More blah
Official DisclaimerThis presentation
reflects the author’s personal opinions and may depict a simplified
version of the facts without any malice intended. Any and all errors
Mobile network history Many people still have these phones
GenG
Year DataRate
RadioTech
3GPPMost of the world
3GPP2USA
1G 1981 0K AnalogNMT AMPS
2.5G 2002 90Kb DigitalGSM, +GPRS, +EDGE
CDMA2000, 1XRTT
2G 1993 50K DigitalGSM, +SMS cdmaOne, IS 95
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Mobile network history 3G: can you hear me now?
GenG
Year DataRate
RadioTech
3GPPMost of the world
3GPP2USA
1G 1981 0K AnalogNMT AMPS
3G 2007 5M DigitalUMTS, HSPAW-CDMA
CDMA2000, EVDO
2G 1993 50K DigitalGSM, +SMS cdmaOne, IS 95
2.5G 2002 90Kb DigitalGSM, +GPRS, +EDGE
CDMA2000, 1XRTT
7
Mobile network history 2 Gb data plan limits
GenG
Year DataRate
RadioTech
3GPPMost of the world
3GPP2USA
1G 1981 0K AnalogNMT AMPS
4G 2011 90M~
DigitalLTE WiMAX
LTE Advanced
2G 1993 50K DigitalGSM, +SMS cdmaOne, IS 95
2.5G 2002 90Kb DigitalGSM, +GPRS, +EDGE
CDMA2000, 1XRTT
3G 2007 5M~
DigitalUMTS, HSPAW-CDMA
CDMA2000, EVDO
8
Mobile network history Wait for 5G
GenG
Year DataRate
RadioTech
3GPPMost of the world
3GPP2USA
1G 1981 0K AnalogNMT AMPS
5G 2020 2Gb Multi-mode
4G 2011 90Mb DigitalLTE WiMAX
LTE Advanced
2G 1993 50K DigitalGSM, +SMS cdmaOne, IS 95
2.5G 2002 90Kb DigitalGSM, +GPRS, +EDGE
CDMA2000, 1XRTT
3G 2007 5Mb DigitalUMTS, HSPAW-CDMA
CDMA2000, EVDO
Global Pervasive Nirvana (GPN)
MSISDNCustomer’s dialable mobile phone number SIM Subscriber information module IMSI Unique customer identifier in the SIM, a long number NAI Customer Identity, number@domain, like an email
addrs IMEI / MEI International Mobile Equipment Identifier, a long
number UMTS Universal Mobile Telephony System PLMN Public Land Mobile Network 3GPP 3rd Generation Partnership Project GPRS General Packet Radio Service HLR / VLR Home Location Register / Visitor Location Register
Terminology Speak the Lingo
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External NetworkCore Network
Network Architecture How your wife can call you from the mall
Voice over IP PacketsFinally, a use for IMS (IP Multimedia Subsystem)
IMS does the Signaling for Multimedia calls Finds parties using their NAI (Network Access Identifier)
A NAI looks like: [email protected] Sets up sessions between the parties domains
Send INVITE to various parties Audio call, video call, SMS, multicast, HTTP, …
Negotiates CODECs for each session Negotiates QoS (Quality of Service) for each session Manages a user’s Presence
“Available for talk”, “busy”, “offline”, “bored”, …
Billing & Service authorization
Comcast Land VoIP
Reliance India IMS
VZW LTE domain
Internet
PSTN
PSTN
17
ChallengesWhat makes mobile networks different
Voice vs. Data transmission Voice requires low latency & high quality Circuit switching vs. Packet switching
Sharing the air with thousands of other UEs
Smooth Handoffs Routing Roaming
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The Radio InterfaceTransmission Techniques for sharing air
FDMA – Frequency Division Multiple Access 395 separate (30kb x 2) channels, typically.
TDMA – Time Division Multiple Access Time slices (2ms) of frequencies, 3 UEs/channel
CDMA – Code Division Multiple Access Frequency hopping
CDMA-TD Combination
Vortex radio coding (New!!!)
Hedy Lamarr invented CDMA
Time
Fre
qu
en
cy
TDMA
call 4 call 5 call 6 call 4
call e call f call g call hcall a call c call d call a
call 9 call 7 call 8 call 9
call 1 call 2 call 3 call 1
Call “e” ended here Call ‘h” took its slot
Time
Fre
qu
en
cy
FDMA
call 5
call 4
call 2
call 3 call 7
call 6call 1
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HandoffsEurope calls them handovers
RNC
RNC
Serv
Serv
Gwy
Gwy
RNC
Serv
Types of Radio Handoffs: Inter frequency: within a cell. Inter cell tower: within a serving node area. Inter serving node: within a carrier. Roaming: between carriers.
Hard vs. Soft handoffs: Hard: break tower connection before making new one. Soft: make a new connection before dropping old one. Softer: make a multiple new connections before dropping. Ultra Soft: use Charmin when you need to go.
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Routing “Marco”, “Polo”, “Marco”, “Polo”, …
Problem: As the phone changes cells, Apps on phone need a fixed IP address But network routing needs changing IP addresses
Solution: IP tunneling / packet encapsulation “Outer” packet address changes “Inner” address stays the same