Nokia - 3G in a Nutshell

3G FundamentalsINDOSAT- NOKIA 3G Demo

Jakarta, 05 Jan 2006Reji WarrierSystem Marketing ManagerRadio Access [email protected]

1 © NOKIA Reji Warrier


Vision of UMTS Specification• Worldwide specified• Clear added value to GSM and backward compatible with GSM/ISDN• Full support for multimedia and advanced services• Generic radio access• Services must not be limited by the network capability.

UMTS Release 99

new radio interface solution• more efficient• more flexible

WCDMA• FDD-mode• TDD-mode

network evolution• enhanced GSM core network• enhanced service infrastructure

International Mobile Telephone - 2000

Direct Spread(on paired frequency spectrum)

CDMA

Multi Carrier(on paired frequency spectrum)

Time Code(on unpaired

frequency spectrum)

Single Carrier(on paired frequency spectrum)

Time Code(on unpairedfrequency spectrum)

TDMA FDMA

cdma2000 UWC-136(EDGE)

(DECT)

Framework for 3G Systems

IMT-2000radio

interfaceoptions

UMTSFDD mode TDD mode

3G systems



HW/SW Changes

Network evolution

MSC&VLR

HLR & AC & EIR

PSTNBSC

BSC

BTS

BTS

TCSM

TCSM

ISDN

A GSM network is made from 3 Sub-Systems (BSS, NSS and OSS)

Value AddedService Platform(s):

SMSC, VMS

Even at the start, VAS (value added services) were part of GSM networks

TRX Change & Transmission Upgrade

HW/SW Changes

IN

IN was introduced for new services and differentiation (e.g. Pre-Paid)

IP Networks

Data Rates in GSM are increased by implementation of Features like HSCSD

SGSN

GGSNIP Networks

GPRS is added to existing networks to support Packed Data

UMTS Rel'3; new BTS, Radio Network Controller, Media Gateway, 3G-SGSN

RNCBTS

3G-SGSN

MGW

GPRS adds improved data services with a new Packets witched backbone Where SGSN and GGSN are two main elements

Higher data rates are obtained by introducing EDGE in the GSM network

The subsystems of UMTS

WCDMA

ATM

Iu

NMSNMS

CNCNRANRAN

O&M

Uu

UEUE

UE = User EquipmentRAN = Radio Acces NetworkCN = Core NetworkNMS = Network Management System

Service PlatformService Platform


UMTS Rel. 99: UTRANCN (Core Network)

circuit switched (cs) domain

packetswitched (ps) domain

3GMSC/VLR

3GSGSN

UTRAN (UMTS Terrestrial Radio Access Network)

RNC

Node B

Node B

RNC

Node B

Node BRadio Network Subsystem (RNS)

Radio Network Subsystem (RNS)

Iub

Iub

Iur

Iu-PS

Iu-CS

Uu

Uu

UE

UE


RNC Radio Network ControllerUE User Equipment = Mobile Equipment (ME) + Universal SIM (USIM)

Radio Network Controller Tasks & Functions

• WCDMA radio resource managementincl. Radio resource management of channel configurations,traffic and control channels, handovers, power control.

• Telecom functionalityincl. Location & connection management, ciphering, Iu and Iub channel management, ATM switching and multiplexing

• Maintenanceincl. Fault localisation and reconfiguration

• Operationincl. RNC and Node B parameter modification


Node B Tasks & Functions

101010010101010001Iub InterfaceATM

Uu InterfaceWCDMA

Cellular Transmission managementManaging ATM switching and multiplexing

over the Iub interface. Control of AAL2/AAL5 connections. Control of the

physical transmission interfaces – E1, PDH, SDH or microwave.

Air Interface management.Controlling Uplink and Downlink

radio paths on the Uu Air Interface. Baseband to RF conversion. Antenna multi-

coupling.

O&M Processing.Interfacing with NMS

and RNC for alarm and control (Operations and Maintenance) functions.

Radio Channel functions.Logical to physical channel

mappings. Encoding/Decoding –Spreading/Despreading user

traffic and signalling.

RNC


Network architecture of Rel 4

• Separation of control plane from user plane, simpler and more efficient

• Statistical multiplexing gain and convergence with PS core as ultimate aim

• More efficient transmission reduces costs this allowing more complex services to be offered

• Evolutionary phase towards Release 5 which in turn will offer even more advanced services

• GERAN implementation


HSDPA Release 5

• AMC, adaptative modulation and coding 16 QuadratureAmplitude Modulation used in good radio link conditions

• Automatic Retransmission Query (ARQ) as error detectionmechanism provides efficient retransmissons

• support for services requiring high data rates in downlink, e.g. Internet browsing and video on demand.

• High data rates up to 10Mbit/s


Wireless Principle

• Transmission Type

• Simplex Transmission• Half Duplex Transmission• Duplex Transmission

• Radio Communication

• Analogue :- Voice over the air• Digital :- 0s & 1s are transmitted over the air


FDD and TDD

Duplex Transmission

Time Division DuplexFrequency Division Duplex


frequency

time

frequencytim

e

Uplin

k

Uplink

Uplink

UplinkDown

link

Downlink

Downlink

Downlink

With FDMA, the users transmit simultaneously using separate frequencies

frequency


time

mobile

phon

e 1

mobile

phon

e 4

mobile

phon

e 2mob

ile ph

one 3

carrier band

Used for broadcast. Different broadcasts in the same region. FDMA is used in cellular communications. Used higher power and lower frequencies

Space Division Multiple Access

Growing customer demand.Geographical region intosmaller areas called “cells.”Each cell would use a frequency different than those ofits nearest neighbours.Same frequency can be used multiple times in the same geographical region.Two freq in one cell.Basic limit of one call per frequency.



TDMA frame

frequency

time

TDMA frame

Mobile Phone 1

Mobile Phone 1

Mobile Phone 1

Mobile Phone 2

Mobile Phone 2

Mobile Phone 2

Mobile Phone 3

Mobile Phone 3

Mobile Phone 3

Mobile Phone 4

Mobile Phone 4

carrier band

TDMA divides the frequency into multiple time slices

Dividing the frequency into multiple time slices so that multiple users can access the same frequency at the same time.

Code Division Multiple Access

The user data is combined at the transmitter’s side with a code, then transmitted. On air, all transmission get mixed. At the receiver’sside, the same code is used as in the transmitter’s side.


Sharing the frequency by using different codes

Codes

Power (P)

Time

Frequency


WCDMA air interface properties

FrequencyBand

Duration(spreading factor)

Power

WCDMAOriginating Bit Received Bit


Spreading and sharing the same space

ff

User AUser A

DataData

PP P

P P

DespreadDespreadUser A signalUser B signalat the receiverat the receiver

ff

ff

ff


ff

User BUser BPP

Data afterData afterspreadingspreading

TransmissionTransmissionover the airover the air

ffP

Managing interference in CDMA

DespreadDespreadsignal at signal at the receiverthe receiver

Transm issionTransm issionover the airover the air

signalsignal

interferenceinterference

ff ff

pppp signalsignal

interferenceinterference


3G Access Rate targets

Environment RT Service Peak Rate(Delay fixedfixed 20 – 300 ms)

NRT Service Peak Rate(Delay variesvaries 20 – 300 ms)

Rural Outdoor(Speed < 250 km/h)

144 – 384 kb/s 144 – 384 kb/s

Urban/Suburban(Speed < 150 km/h)

384 – 512 kb/s 384 – 512 kb/s

Indoor/Low Range Outdoor(Speed < 10 km/h)

- 2 Mb/s(Special conditions)

- 2 Mb/s (Special conditions)

Pedestrian & Office (<10 km/h):bit rate <= 2 Mb/s

Outdoor (< 150 km/h):bit rate 384 kb/s, target 512 kb/s

Outdoor (<250 km/h):bit rate 144 kb/s, preferably more

3G Radio Access


CDMA theory


Differences between WCDMA & GSM

WCDMA GSM

Carrier spacing 5 MHz 200 kHzFrequency reuse factor 1 1–18Power controlfrequency

1500 Hz 2 Hz or lower

Quality control Radio resourcemanagement algorithms

Network planning(frequency planning)

Frequency diversity 5 MHz bandwidth givesmultipath diversity with

Rake receiver

Frequency hopping

Packet data Load-based packetscheduling

Timeslot basedscheduling with GPRS

Downlink transmitdiversity

Supported forimproving downlink

capacity

Not supported by thestandard, but can be

applied

High bit rates

Spectral efficiency

Different quality

requirements

Efficient packet data


WCDMA Capacity

f1

128 kbps

64 kbps

8 kbps

f1

144 kbps

64 kbps


NOTE!WCDMA capacity is a function of radio environment, user mobility/location and propagation conditions. Examples above are just examples of WCDMA cell capacities of a 3 sector macro cell BS configuration.

Mobile Station

64 kbps

144 kbps

Base Station

"Cell breathing"

The size of cell variesaccording the traffic load

144 kbps

64 kbps

64 kbps

High load 800 kbps-> smaller coverage

Low load 200 kbps-> large coverage

Where are codes used?

In the Uplink (UE → Node B), the user's data and

signalling information is separated by

Channelisation Codes

datasignalling

In the Downlink (Node B→UE), cells are seperated by Scrambling Codes

In the Uplink (UE → Node B), terminals are separated by

Scrambling Codes

In the Downlink (Node B → UE), user connections are separated by

Channelisation Codes

Dedicated User Channel

Channel Coding

TxRAKE Air interface

Signalling Data

Call set-up,SMS etc.messages

Voice, videoand other user data

Channels

Radio Framing

Spreading &Channelisation

Scrambling

Modulation


Interference in CDMA• Interference is

caused by mobiles in the neighbouring cells as well as by mobiles in the same cell area (uplink)

• Total interference experienced by BTS is summary of all those

• If interference increases the needed output power from MS needs to be increased as well.

Signal

Interference


Power control in WCDMA

• Fast, accurate power control is of utmost importance – particularly in UL;• UEs transmit continuously• WCMDA often uses 1 frequency• Poor PC leads to increase interference > reduced capacity

• From BTS perspective every UE accessing network increase interference

• WCMDA capacity is proportional to interference level > minimise interference

• PC maintains link quality by adjusting UE (UL) and BTS (DL) powers every slot

• Mitigates 'near far effect', by providing minimum required power for each connection

• UEs and BTSs should always be at the lowest possible transmission power

• PC utilises Signal-to-Interference Ratio (SIR) – independently for each connection

• Provides protection against shadowing and fast fading


Power control

Node BP1 P2

Node B RNC

Open Loop Power Control (Initial Access)

Closed Loop Power Control

Outer Loop Power Control


Open Loop Power Control• Controlled by UE• Determines how much power UE should use during random access procedure (UL)• Network informs UE of current network status;

• CPICH power (RNP parameter)• UL required C/I ratio (RNP parameter)• UL interference

• UE uses these parameters to calculate initial power of RACH preamble• If access request is not detected power of preamble is increased in steps• After detection of MS signal, the initial SIR is calculated in RNC

Preamble PreamblePreamble

Preamble

MS

Out

put

Pow

er AICH

Mesage Part

RACH


Fast Loop Power Control• Located in BTS and UE• Controls the power of the dedicated physical channels• Power control changes can occur every slot (i.e. 1500 times per second)• BTS and UE continuously compare recevied SIR with SIR target and inform each other

to either increase or decrease its power (using TPC commands)

WithoutPower Control

With OptimumPower Control

MS1

MS2

MS3

MS4

Rec

eive

d po

wer

at B

S

MS1MS2

MS3MS4

MS1 MS2 MS3 MS4

Rec

eive

d po

wer

at B

S30 © NOKIA Reji Warrier

Closed Loop Power Control• Adjusts the SIR for every user based on BER/FER observation. Initial, max. and min.

SIR values are set by AC• Needed to track changes in radio environment• Aims to provide required quality• UL quality evaluation is made after MDC• RNP parameters control the threshold comparison process for SIR target and the

reporting of these results• If SIR target reaches its maximum (I.e. radio conditions deteriorate even though SIR

target is inceased, system has to take action;• inter-frequency / inter-system handover• RRC connnection release


Handover types


CNRNC

MSCBSC

GSM900/1800GSM900/1800

WCDMA FDDWCDMA FDD

Inter-SystemInter-System

Intra-SystemIntra-System

WCDMA TDDWCDMA TDD

Inter-SystemInter-System

Active cells and soft handovers

CNRNC

frame reliability info

frame reliability infoframe

selection /duplication

BS1 BS2

Soft handover windowP

2) Add BS2

1) Connection to BS1

3) Drop BS1

4) Connection to BS2


Handover types

Soft Handover


4

Hard/Inter-Frequency Handover

Softer Handover

Inter-System Handover

Node B

Frequencyf1

Frequencyf1

Frequencyf1

Frequencyf2

UMTS GSM900/1800

Sector 1f1

Sector 2f1

Sector 3f1

Multipath Signalthrough Sector 1

Multipath Signalthrough Sector 3

Frequencyf1

Frequencyf1

RNC RNCIur

Iub Iub

Node B

Node B Node B

Node BNode B

Node B

Node B BTS

Load Control

Estimated capacity for NRT traffic.

Measured load caused by non-controllable load (RT)

Overloadthreshold x

Load Targetthreshold y

Pow

er

Time

Preventive Load Control

Overload Control


Admission Control

Planned uplink interference margin; defines the optimum operating poit up to which the AC can operate.

Defines the limit (the first UL overload threshold) for the UL interference margin, after which the BS starts its load control actions to prevent overload.

Offset

25

Inte

rfer

ence

Mar

gin

(dB)

20

15

10

5

0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Load


AdmissionControl

LoadControl

PacketScheduler

PrxTarget orPtxTarget

PrxTarget+PrxOffset orPtxTarget+PtxOffset

PrxThreshold orPtxThreshold

P_CellMax

No actionsPS increases theamount of NRT

bearersAC admits RT

bearers normally

No actions

Load preventive LCactions

Overload actions

AC does not admitnew bearers

AC does not admitnew bearers

PS decreases thebitrates and drops

NRT bearers

PS decreases thebitrates of NRT

bearers

PS does notincrease NRT load,

but can changeNRT bitrates

Power

Load

Summary


Features of WCDMA

• Efficient use of spectrum

• Limited frequency management

• Low mobile station transmit power

• Uplink and downlink resource utilisation independent

• Wide variety of data rates

• Improvement of multi-path resolution

• Statistical multiplexing advantage

• Increased standby-time from higher rate control channels.


Features of WCDMA

• Efficient use of spectrum ( disco trans – dec inter, incr cap “ NRT data when not enough RT..)

• Limited frequency management

• Low mobile station transmit power

• Uplink and downlink resource utilisation independent ( Diff bit rates in UL/DL)

• Wide variety of data rates

• Improvement of multi-path resolution

• Statistical multiplexing advantage ( More channels/user in one carrier)

• Increased standby-time from higher rate control channels. ( wideband spectrum, ms listens only part of the time )


Key operator benefits

• New service capabilities means new business opportunities for operators, (further differentiation)

• Revenue opportunity with increased data/voice traffic

• New frequency spectrum

• The path towards IP mobility


Key end-user benefits

• Integrated customised services

• Simplified service provisioning and service upgrades

• Wireless personal Internet

• Multimedia messaging

• Enhanced e-mail

• Telecommuting

• Improved quality of service

• Support for video/audio clips


Thank You

Jakarta, 05 Jan 2006


Review Questions

1. In UMTS, there are two methods used for transport through the air interface.

The first is UMTS-FDD. What is the second one?

a. TDD, Time Doubled Division

b. CDD, Code Division Duplex

c. TDD, Time Division Duplex

d. CDD, Code Divided Data


Review Questions

2. Which of the following sentences best describes the phenomenon called cell breathing?

a. When more capacity is used, the cell spreads in size.

b. When more capacity is used, the cell shrinks in size.

c. The cell will adjust its size in line with the furthest users.

For example, if the user is 5 km away, the cell is 5 km.

If the user is 2 km away, the cell is 2 km.

d. Cell breathing is the height of the cell: from 2 - 3 km towards

the atmosphere.


Review Questions

3. There are two types of codes used in UMTS. These are the channelisation and scrambling codes.

Why are the scrambling codes used?

a. To separate downlink physical channels in a cell.

b. To separate user data and signalling in the network.

c. As security to check if the User Equipment (UE) is not stolen.

d. To separate different cells in the downlink direction.


Review Questions

4. The Iur-interface is used between two RNCs. What is the purpose of this interface?

a. There is no use for this interface.

b. It is used for soft handovers.

c. It is used to transfer software files.

d. It is used when a RNC has a hardware failure.


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Nokia - 3G in a Nutshell