Mobility 101

You too can spew TLAs like a pro

March 2012

Rajaram Pejaverraj@pejaver.com

Note: The views presented here are solely those of the author and do not necessarily reflect any views of any one else. Please contact the author if you have comments or objections regarding the content.

© Rajaram Pejaver, 2012

2

OutlineCell phone networks

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

are solely attributable to the

author.

© Rajaram Pejaver, 2012

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Mobile network history or what the **ck is 4G?

GenG

Year DataRate

RadioTech

3GPPMost of the world

3GPP2USA

1G 1981 0K AnalogNMT AMPS

4

Mobile network history or what the heck is 4G?

GenG

Year DataRate

RadioTech

3GPPMost of the world

3GPP2USA

1G 1981 0K AnalogNMT AMPS

2G 1993 50K DigitalGSM, +SMS cdmaOne, IS 95

5

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

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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

Radio Access Network

RNC

RNC

RNC

UE

Foreign Core

Internet

Internet

Backhaul links•Authentication•Billing•Mobility•Services•CALEA

PSTN

Gateway Nodes

Serving Nodes

Voice Voice

Data

Data

Data

Data

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External NetworkCore Network

Standards - 1GSM, standardized by 3GPP, deployed worldwide

Radio Access Network

BSC

BSC

BSC

UE

Foreign Core

PSTN

Backhaul links•Authentication•Billing•Mobility•Services•CALEA

PSTN

Gateway Nodes

Serving Nodes

Voice Voice

Voice

Voice

Voice

Voice

MCS GMSC

MCS GMSC

ISUPA

A

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External Network

Standards - 2CDMA 2000, Qualcomm’s baby, blessed by 3GPP2

BSC

BSC

BTS

UE

Foreign Core

Internet

Internet

Backhaul links•Authentication•Billing•Mobility•Services•CALEA

PSTN

Gateway Nodes

Serving Nodes

Voice Voice

Data

Data

Data

Data

BSC MSC

BSC PDSN

A1/A2/A5A7

A7

A3

A10/A11

PCF

PCF

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External NetworkCore Network: UMTS

Standards - 3GSM begat UMTS, with GPRS & EDGE

UMTS Terrestrial Radio Access Network

RNC

RNC

RNC

UE

Foreign Core

Internet

Internet

Backhaul links•Authentication•Billing•Mobility•Services•CALEA

PSTN

Gateway Nodes

Serving Nodes

Voice Voice

Data

Data

Data

Data

MCS GMSC

SGSN GGSN

ISUPIuCS

IuPS

IuPS

Gn

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External NetworkCore Network: UMTS

Standards - 4then on the fifth day, W-CDMA took upon UMTS

RNC

RNC

RNC

UE

Foreign Core

Internet

Internet

Backhaul links•Authentication•Billing•Mobility•Services•CALEA

PSTN

Gateway Nodes

Serving Nodes

Voice Voice

Data

Data

Data

Data

MCS GMSC

SGSN GGSN

ISUPIuCS

IuPS

IuPS

Gn

UMTS Terrestrial Radio Access Network

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External NetworkEnhanced Packet Core

Standards - 5and lo, UMTS begat EPC for LTE

UE

Foreign Core

Internet

Internet

Backhaul links•Authentication•Billing•Mobility•Services•CALEA

PSTN

Gateway Nodes

Serving Nodes

Data

Data

Data

Data

IMSSGW PGWS1-U

S5

S5

S8

PGW

S11

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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: 2122211234@phone.net 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

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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

Tunneling methods used: CDMA2000: GRE tunnels GSM/W-CDMA: GTP v1 tunnels LTE: GTP v2 tunnels

Data

Data

IPHdr

UDPHdr

PPPHdr

IPHdr

TCPHdr

HTTPDataData

Inner pkt

Outer pkt

Thank you for listening!!Now get back to work

21© Rajaram Pejaver, 2012

http://pejaver.com/Papers/Mobility101.pps GPL copyleft terms, do not reuse for profit.