cellular mobile telephony€¦ · hlr — home location register auc — authentication server gmsc...

Cellular Mobile Telephony

Chalmers Data 2008-12-11

Early Mobile Radio Telephone in 1924

© Ericsson AB 2008 Ericsson Internal Cellular Mobile Telephony 2008-12-102

Cellular Mobile TelephonyEssential inventions/criteria's

� Frequency modulation

� Antenna diversity

� Cellular concept

– Bell Labs (1957 & 1960)

� Frequency reuse

– Typically every 7 cells

� Handoff as caller moves

� Modified CO (Central Office) switch, e.g. AXE

– HLR, paging, handoffs

� Sectors improve reuse

– Every 3 cells possible

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6

7

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572

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11

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13


NMT1G – Frequency Division Multiple Access

� Nordic Mobile Telephony (NMT)

� Deployed in Sweden, Norway, Demark & Finland

� Launched 1981; now largely retired

� Spectrum: 450 MHz; later at 900 MHz (NMT900)


GSM2G – Time Division Multiple Access

� « Groupe Special Mobile », later changed to « Global System for Mobile »

– Joint European effort beginning in 1982

– Focus on seamless roaming across Europe

� Services launched 1991– Time division multiple access (8 users per 200KHz)

– 900 MHz band; later extended by 1800MHz (WW non US)

– Added 1900 MHz (US PCS bands)

� GSM is dominant world standard today– Well defined interfaces; many competitors

– Network effect (Metcalfe’s law) took hold in late 1990s

– Tri-band GSM phone can roam the world today


W-CDMA (UMTS)3G – Code Division Multiple Access

� Wideband CDMA– Standard for Universal Mobile Telephone Service (UMTS)

� Committed standard for Europe and likely migration path for other GSM operators

– Leverages GSM’s dominant position

� Requires substantial new spectrum– 5 MHz each way (symmetric)

� Legally mandated in Europe and elsewhere

� Sales of new spectrum completed in Europe– At prices that now seem exorbitant


LTE4G

� Aim to 100 Mbps (moving) & 1 Gbps (stationary)

� Seamless roaming across heterogeneous networks

� Sophisticated multiple access schemes– DL: OFDMA with Cyclic Prefix (CP)

– UL: Single Carrier FDMA (SC-FDMA) with CP

� Adaptive modulation and coding– QPSK, 16QAM, and 64QAM

– 1/3 coding rate, two 8-state constituent encoders

� Advanced MIMO spatial multiplexing techniques– (2 or 4) x (2 or 4) downlink and uplink


GSM/WCDMA coverage map

GSM Coverage

Source: Chart: GSM Association January 2007WCDMA Coverage


Migration To 3G and beyond

CDMA

GSM

TDMA

PHS (IP-Based)

64 Kbps

GPRS

115 Kbps

CDMA 1xRTT

144 Kbps

EDGE

384 Kbps

cdma2000

1X-EV-DV

Over 2.4 Mbps

W-CDMA

(UMTS)

Up to 2 Mbps

2G2.5G

2.75G 3G

1992 - 2000+2001+

2003+

1G

1984 - 1996+

2003 - 2004+

TACS

NMT

AMPS

GSM/

GPRS

(Overlay) 115 Kbps

9.6 Kbps

9.6 Kbps

14.4 Kbps/ 64 Kbps

9.6 Kbps

PDC

Analog Voice

Digital Voice

Packet Data

IntermediateMultimedia

Multimedia

PHS

TD-SCDMA

2 Mbps?

9.6 Kbps

iDEN

(Overlay)

iDEN

Source: U.S. Bancorp Piper Jaffray

3.5G (4G?)All IP

LTELTE

Up to 100 Mbps,eventually

UMBUMB

2007+ - 2010+

UMB - Ultra Mobile Broadband


Technology trends

� Faster networks

� More powerful processors

� Higher memory capacity

Leverage commercial evolution


CDMA

Growth in mobile subscriptionsWireless subscriptions worldwide

0

1000

2000

3000

4000

5000

6000

2005 2006 2007 2008 2009 2010 2011 2012

Re

po

rte

d S

ub

sc

rip

tio

ns

(M

illi

on

s)

3G and LTE

GSM/EDGE

Mobile WiMAX (yellow)

2006

2005

2004

3GPP family

Main growth in the 3GPP technology

Other technologies (gray)


Mobil Broadband Evolution

28 Mbps 160 Mbps

Leading Mobile Broadband Capabilities, now and in the future ..

1 000

100

10

1

0,1

2004 2005 2006 2007 2008 2009 2010

Mbps

Downlink

Uplink

Turbo 3G (HSPA)

HSPA Evolved 3G LTE

3.6 Mbps

EDGE

472 kbps

EDGE evolution

1 Mbps

Turbo 3G (HSPA)

14,4 Mbps

3G

2GDownlink


StandardizationGSM standardization

� 1982 -- European Conference of Postal and Telecommunications Administrations (CEPT)

– Create “Groupe Spécial Mobile” (GSM), a standard for a mobile telephone system intended to be used across Europe

� 1987 -- A memorandum of understanding was signed by 13 countries to develop a common cellular telephone system across Europe

� 1988 -- European Telecommunications Standards Institute (ETSI)– Created by CEPT

– GSM responsibility transferred to ETSI

� 1990 -- Phase I of the GSM specifications published.

� 1991 -- First GSM network was launched

� 1993 -- Over a million subscribers using GSM– 70 carriers across 48 countries

� 1998 – 3GPP formed


3G Partnership ProjectDefining migration from GSM to UMTS (W-CDMA)

� ETSI, Association of Radio Industries and Businesses/Telecommunication Technology Committee (ARIB/TTC) (Japan), China Communications Standards Association, Alliance for Telecommunications Industry Solutions (North America) and Telecommunications Technology Association (South Korea)

� 3GPP Release 99 (2000)– Specified the first UMTS 3G networks, incorporating a CDMA air interface

� 3GPP Release 4 (2001)– Adds softswitch/ voice gateways, packet core and all-IP Core Network

� 3GPP Release 5 (2002)– First IP Multimedia Services (IMS) w/ SIP & QoS and HSDPA

� 3GPP Release 6 (2004)– “All IP” network and adds HSUPA and MBMS (core of MobileTV)

� 3GPP Release 7 (2007)– Decreasing latency, improvements to QoS, HSPA+ (High Speed Packet

Access Evolution) and EDGE Evolution

� 3GPP Release 8 (2009)– LTE, All-IP Network (SAE) (System Architecture Evolution)


ArchitectureTypical 2G

BTS — Base Transceiver Station

BSC — Base Station Controller

MSC — Mobile Switching Center

VLR — Visitor Location Register

HLR — Home Location Register

BTS

BSC

MSC/VLR

HLRBSC

GMSC

CO

BSC

BSCMSC/VLR

CO

PSTN

PLMN

CO

Tandem Tandem

SMS-SC

PSDN


ArchitectureGSM 2G

BSS — Base Station System



MS — Mobile Station

NSS — Network Sub-System

MSC — Mobile-service Switching Controller



AuC — Authentication Server

GMSC — Gateway MSC

SS7BTS

BSCMSC

VLR

HLRAuC

GMSC

BSS

PSTN

NSS

A

E

C

D

PSTNAbis

B

H

MS

GSM — Global System for Mobile communication


GPRS — 2.5G for GSM

� General Packet Radio Service– First introduction of packet technology

� Aggregate radio channels– Support higher data rates (115 kbps, 8 TS x 14.4 kbps)

– Subject to channel availability/resource allocation

� Share aggregate channels among multiple users

� All new IP-based data infrastructure

� No changes to voice network


ArchitectureGSM 2.5G

SS7BTS

BSCMSC

VLR

HLRAuC

GMSC

BSS

PSTN

NSS

A

E

C

D

PSTNAbis

B

H

MS




NSS — Network Sub-System






SGSN — Serving GPRS Support Node

GGSN — Gateway GPRS Support Node

GPRS — General Packet Radio Service

IP

2G+ MS (voice & data)

PSDNGi

SGSN

Gr

Gb

Gs

GGSN

Gc

Gn

2G MS (voice only)


EDGEEnhanced Data rates for Global Evolution

� Increased data rates with GSM compatibility– Still 200 KHz bands; still TDMA

– 8-PSK modulation: 3 bits/symbol give 3X data rate

– 9 MCS (Modulation Coding Schemes), 8.8 – 59.2 kpbs/TS

– Shorter range (more sensitive to noise/interference)


3G rel99 Architecture (UMTS)3G Radios

SS7

IP

BTS

BSCMSC

VLR

HLRAuC

GMSC

BSS

SGSN GGSN

PSTN

PSDN

CN

CD

GcGr

Gn Gi

Abis

Gs

B

H




RNS — Radio Network System

RNC — Radio Network Controller

CN — Core Network








AE PSTN

2G MS (voice only)


UMTS — Universal Mobile Telecommunication System

Gb

3G UE (voice & data)

Node B

RNC

RNS

Iub

IuCS

ATM

IuPS

Major advantage:

Shared Core NW


3G rel4 Architecture (UMTS)Soft Switching

SS7

IP/ATM

BTS

BSCMSC Server

VLR

HLRAuC

GMSC server

BSS

SGSN GGSN

PSTN

PSDN

CN

CD

GcGr

Gn Gi

Gb

Abis

Gs

B

H




RNS — Radio Network System

RNC — Radio Network Controller

CN — Core Network








ANc

2G MS (voice only)


Node B

RNC

RNS

Iub

IuCS

IuPS


Mc

CS-MGW

CS-MGWNb

PSTNMc

ATM


3G rel5 Architecture (UMTS)IP Multimedia Subsystem (IMS)

Gb/IuPS

A/IuCS

SS7

IP/ATM

BTS

BSCMSC Server

VLR

HSSAuC

GMSC server

BSS

SGSN GGSN

PSTN

CN

CD

GcGr

Gn Gi

Abis

Gs

B

H

IM — IP Multimedia sub-system

MRF — Media Resource Function

CSCF — Call State Control Function

MGCF — Media Gateway Control Function (Mc=H248,Mg=SIP)

IM-MGW — IP Multimedia-MGW

Nc

2G MS (voice only)


Node B

RNC

RNS

Iub


Mc

CS-MGW

CS-MGWNb

PSTNMc

IuCS

IuPS

ATM

IM

IPPSTN

Mc

MGCF

IM-MGW

MRF

CSCF

Mg

Gs

IP Network


3GPP Rel.6 Objectives

� IP Multimedia Services, phase 2– IMS messaging and group management

� Wireless LAN inter-working

� Speech enabled services– Distributed speech recognition (DSR)

� Number portability

� Other enhancements


3G rel6 Architecture (UMTS)IP Multimedia Subsystem (IMS)

Gb/IuPS

A/IuCS

SS7

IP/ATM

BTS

BSCMSC Server

VLR

HSSAuC

GMSC server

BSS

SGSN GGSN

PSTN

CN

CD

GcGr

Gn Gi

Abis

Gs

B

H

IM — IP Multimedia sub-system


CSCF — Call State Control Function

MGCF — Media Gateway Control Function (Mc=H248,Mg=SIP)

IM-MGW — IP Multimedia-MGW

Nc

2G MS (voice only)


Node B

RNC

RNS

Iub


Mc

CS-MGW

CS-MGWNb

PSTNMc

IuCS

IuPS

ATM

IM

IPPSTN

Mc

MGCF

IM-MGW

MRF

CSCF

Mg

Gs

IP Network


PSTN-to-Mobile Call

(STP)

(SCP)

PSTNPLMN

(SSP)(SSP)BSSMS

PLMN(Home)(Visitor)

(STP)

HLR

GMSC

(SSP)

VMSC

VLR

IAM

6

2

Where is the subscriber?

5

Routing Info

3Provide Roaming

4

SCP

1

IAM

514 581 ...

ISUP

MAP/ IS41 (over TCAP)

Signalingover SS7


Network Planes

� Like PSTN, 2G mobile networks have one plane for voice circuits and another plane for signaling

� Some elements reside only in the signaling plane– HLR, VLR, AuC, SMS Center, Voice Mail

– MSC -> MSC-S (signaling) + MGw (transport)

MSC

HLR

MSCVLR

Transport Plane (Voice, Data)

Signaling Plane (SS7 -> IP)MSC

VMS SMS-C

VLR

VLR AuC


Signaling in Core Network

� Historically based on SS7– ISUP and specific Application Parts

� Trend: Migration to SIGTRAN (SS7 over IP)

� GSM MAP and ANSI-41 services– Mobility, call-handling, O&M

– Authentication, supplementary services

– SMS, …

� Location registers for mobility management– HLR: home location register has permanent data

– VLR: visitor location register keeps local sub-set copy of roamer’s subscriber data


SS7 -- Signaling System #7

SSP

SSP SSP

STP

STP

STP

STP

SCP

SCP

PhonePhone

Voice Network

SS7 signaling network

Subscriber LineVoice TrunkSignaling Link

Appl.Appl.

Appl.

SSP = Service Switching PointSTP = Signal Transfer PointSCP = Service Control Point


Traditional STP Network- TDM or ATM based (SL or HSL)

Bandwidthlimitations

MSCMSC

STPSTP

STPSTP

HLRHLR

STPSTP

STPSTP

HLRHLR

MSCMSC MSCMSC MSCMSC MSCMSC MSCMSC MSCMSC--SS MSCMSC--SS MSCMSC--SS MSCMSC--SS

STPs are physical connection and aggregation points

Meshed/hierarchicalSTP network

Challenges:

• growing signaling load• broadband signaling capabilities

• new IP based applications• OPEX reduction

MGWMGW MGWMGW MGWMGW MGWMGWMGWMGW MGWMGW

ATM or IP based

SS7 routingintelligence in

SEPs and STPs


SS7 over IP Network

Bandwidthflexibility

L3/IP routingintelligence in

routers

SRP/SRP/

SGWSGW

SS7 routingintelligence only

in SEPs

IP NetworkIP Network

HLRHLR HLRHLR

MSCMSC MSCMSC MSCMSC--SS MSCMSC--SSMGWMGW MGWMGW


Physical Layer

SCCP

TCAP

IP

SCTP

M3UAMTP3

M2UA

SUA

M2PA

Physical Layer

SCCP

TCAP

IP

SCTP

M3UAMTP3

M2UA

SUA

M2PA

SIGTRAN Protocol Suite

IP and Physical Layer• Network-wide addressing• Routing, incl. Routing protocols• Quality of Service• Security

SCTP(Stream Control Transmission Protocol)

• Reliable, connection-oriented transport service on anunreliable IP network

• In-sequence delivery of packetswith delays acceptable for SS7

M3UA (MTP Level 3 User Adaptation)

• Mimics MTP3 services forMTP3 Users

• Supports some SS7 Network Management procedures


Physical Layer

SCCP

TCAP

IP

SCTP

M3UAMTP3

M2UA

SUA

M2PA

Physical Layer

SCCP

TCAP

IP

SCTP

M3UAMTP3

M2UA

SUA

M2PA

SIGTRAN Protocol Suite

MTP (Message Transfer Part)

Part of SS7. Responsible for reliable, unduplicated and in-sequence transport of SS7 messages between communication partners

SCCP (Signaling Connection Control Part)

provides routing, flow control, segmentation, connection-orientation, and error correction

TCAP (Transaction Capabilities Appl. Part)

Facilitate multiple concurrent dialogs between the same sub-systems on the same machines


IMS Architecture

PS

UE

SGSN

Internet

HSS

IMS

P-CSCF

GGSN

Application Server

SIP phone

Media Server

Gi/Mb

Mw Mg

Mb

Mb

Gi

Mn

MGCF

TDM

IM-MGW

ISUP

Mb

Mb

CxGo

Signaling

CSCF — Call Session Control Function

IM-MGW — IM-Media Gateway

MGCF — Media Gateway Control Function


MRF

Gm

SIP

Mp

PSTN

CPE

ISC

CSCF


Core Network Protocol StackOSI 7

OSI 7

OSI 4

OSI 3

OSI 2

OSI 1

Application

PresentationSession

Transport

Network

Data Link

Physical

cellular mobile telephony€¦ · hlr — home location register auc — authentication server gmsc...

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