200041980 basic theory wcdma v2

WNMP WCDMA

WCDMA Basic Theory

WIRELESS NETWORK MASTER PLANNING

By: Manuel M. Aquino Jr.

Future Access Technologies

Access Network Planning Department

WNMP WCDMA

The Goal of this Course

After this course, you should be able to

• Understand the technology behind

WCDMA and its advantages

• Understand the roots and roadmap

of WCDMA

• Be familiar with the basic

architecture of a WCDMA network

WNMP WCDMA

WCDMA Overview

Advantages of WCDMA

WCDMA Basic Principle

WCDMA Architecture

Content

Training GLOBE TELECOM

WNMP WCDMA

11GG 22GG 33GG 44GG

Analog

cellular DDiiggiittaall cceelllluullaarr DDiiggiittaall cceelllluullaarr Hybrid IP based

VVooiiccee VVooiiccee //ddaattaa VVooiiccee // hhiigghh ssppeeeedd

ddaattaa VVooiiccee // vveerryy hhiigghh

ssppeeeedd ddaattaa

AAMMPPSS

TTAACCSS CCDDMMAA 11XXRRtttt

GGSSMM GGPPRRSS

CCDDMMAA22000000

WCDMA

HSDPA

9.6 Kbps 64 Kbps/144 Kbps 22 MMbbppss >>1100 MMbbppss

8800’’ 11999922 11999999 22000011 22000044 Not yet deployed

Evolution of Mobile Communications

AMPS: Advanced Mobile Phone System

TACS: Total Access Communication System

GPRS: General Packet Radio Services

WNMP WCDMA


1G – 1st Generation: Analog Cellular

1) Feature:

• frequency division multiple access (FDMA)

• analog signal

• narrow band

2)Main mode: AMPS TACS NMT

3)Limitations:

• hard to develop digital bearer services

• cannot adopt to digitization of fixed networks

• low frequency efficiency

• cannot meet larger capacity requirements

• easy to be eavesdropped

WNMP WCDMA


2G – 2nd Generation: Digital Cellular

1) Feature:

• time division multiple access (TDMA)

narrow code division multiple access (N-CDMA)

• digital signal, narrow band

• strong anti-interference capability

• security is guaranteed with authentication and encryption

• can support ISDN

2) Main mode: GSM D-AMPS N-CDMA

3)Limitations:

• Narrow bandwidth unable to provide various broadband information services such as high speed data services.

WNMP WCDMA


3G – 3rd Generation: Digital Cellular – IMT 2000

1) Feature:

• code division multiple access (CDMA)

• digital signal

• broadband

• integrated service system integrating all current mobile telephone system functions providing multiple services

• large capacity

2) meaning of ‘2000’:

• frequency spectrum around 2000MHz

• data rate up to 2000kbps

• putting into business about 2000

3) Main mode: WCDMA CDMA2000 TD-SCDMA

WNMP WCDMA


4G – 4th Generation: Hybrid IP Based Mobile Network

1) Feature:

• 3G Mobile Voice and Data Service, Broadband

Access, Video Call

• > 10 Mbps Data Rate

• In principle will allow high-quality smooth video

transmission

WNMP WCDMA

Birth of IMT2000

FPLMTS 1985

1996 IMT 2000

Future Public Land Mobile

Telecommunications System

International Mobile

Telecommunications 2000

WCDMA TD-SCDMA CDMA2000 UMTS

3GPP 3GPP2

DECT

WCDMA-UMTS CDMA 2000

WCDMA-FOMA

TDMA

TD-SCDMA

WNMP WCDMA

The Goal of IMT 2000

• Higher transmit rate 2Mbps

• Rich and colorful service

• Good voice quality

• Larger capacity

• Lower cost

• Good security performance

• High frequency efficiency

• Increased Mobility

• Easy to transition from 2G

WNMP WCDMA

Standard Framework of IMT 2000

UIM MT RAN CN CN

UIM-MT

Interface

MT-RAN

Interface

RAN-CN

Interface NNI

Core Networks of other

IMT-2000 family members

WNMP WCDMA

Family concept

3G

standards

CN based on MAP

TD-SCDMA

CN based on MAP

CDMA2000

CN based on ANSI-41

CDMA is the main technology of 3G

WCDMA

WNMP WCDMA

WCDMA

IS-41 CN

GSM GSM CN

NNI

CN(Core Network) 2G/3G Radio Network

WCDMA

IS-95

CDMA2000

Family concept

WNMP WCDMA

3G Standard Organization

WNMP WCDMA

WNMP WCDMA

2Mbps 64kbps

WCDMA

GSM

EDGE

2G 2.5G 3G

9.6kbps

WCDMA Technology Evolution

Wideband Code Division Multiple Access uses direct

sequence spread-spectrum technology to transmit a number of

independent conversations across 5MHz segments of the

radio spectrum.

GPRS

144kbps

2.75G

WNMP WCDMA

UMTS Protocol Version Evolution

R4

R5

R99

• Inherit all the service

and function of

2G(GSM and GPRS）

• CN is composed of

CS domain and PS

domain

• WCDMA UTRAN

access

• Iu interface between

RAN and CN

• Inherit all the service and

function of R99

• CS domain change:

control is separated from

bearer，the function of

MSC can be complete by

split SERVER,MGW

• Voice supported by CS

domain, supporting:

TDM,ATM,IP

• Inherit all the service and

function of R4

• Add IMS domain

• Enhanced IP QoS,

supporting End to End IP

multimedia service

2000 2001 2002 Specification complete time

WNMP WCDMA

MSC TMSC

GGSN

UMTS R99 NETWORK ARCHITECTURE

Node B

Node B

RNC

3G Rel. 99

BTS

BTS

BSC

2G

PSTN/

PLMN SS7oIP

SMSC

HLR

SGSN

MGW

WNMP WCDMA

PSTN/

PLMN

GMSC Server MSC Server

MGW

MGW

HLR MSC TMSC

Node B

Node B

RNC

BTS

BTS

BSC

SGSN

GGSN

3G Rel. 4

2G SS7oIP

IP Backbone

SMSC


WNMP WCDMA

PSTN/

PLMN

GMSC Server MSC Server

MGW

MGW

MSC TMSC

BTS

BTS

BSC

SGSN

Node B

Node B

RNC

3G Rel. 5

2G

GGSN

SS7oIP

SMSC

IP Backbone

IMS

HLR


HSS/

HLR

WNMP WCDMA

UMTS

Downlink

Uplink

5 MHz channel FDD mode

Fig. 1

Fig. 2

Uplink and Downlink

5 MHz channel

. . . . . .

TDD mode

Working frequency: 2GHz

Bandwidth: 5MHz

Chip rate: 3.84Mcps

Frame length: 10 ms

WNMP WCDMA

3G Spectrum

WNMP WCDMA

WCDMA Overview

Advantages of WCDMA


WCDMA Architecture

Content


WNMP WCDMA

Frequency

reuse factor is 1;

network design

and expanding

become much

easier

AMPS, D-AMPS, N-AMPS

CDMA

30 kHz

200 kHz

5 MHz

1

8 Users

100 Users @12.2kbps/user

1

1

1 1

1

1 1

1 1

1

1 1

1

1

1 2

3 4

4

3 2

5 6

1 7

Typical Frequency Reuse N=7



GSM

Advantages of WCDMA(1)

WNMP WCDMA

Large capacity

Power

Power

Power

FDMA

TDMA

CDMA

FDMA---Different user use different

frequency

TACS、AMPS

TDMA---Different user use different

time slot of one frequency

GSM、DAMPS

WCDMA---Different user use same

frequency at the same time,but with

different spreading code


WNMP WCDMA

large coverage

almost 2 times than GSM, save money for

operator

Example:cover 1000 km2：

GSM need 200 BTS

WCDMA only need 50 BTS

Attention: exact result need “Link Budget ”


WNMP WCDMA

High privacy and hard to eavesdropped

Spread code

Information signal

TX

Demodulated signal

RX

Spread code

Spread signal

Each user is below

the noise deeply


WNMP WCDMA

WCDMA：”make before break”---soft handoff

Other systems: “make after break”---hard handoff

Use soft handoff: decrease drop-call rate


WNMP WCDMA

Perfect Power Control and voice activation make the UE

Power low, healthy for human body.


Mean Power Max Power

GSM: 125mW 2W

WCDMA: 2mW 200mW

WNMP WCDMA

WCDMA Overview

Advantages of WCDMA


WCDMA Architecture

Content


WNMP WCDMA

WCDMA is a Spread-Spectrum System

Traditional technologies try to squeeze the signal into the minimum required bandwidth

Direct-Sequence Spread spectrum systems mix their input data with a fast spreading sequence and transmit a wideband signal

The spreading sequence is independently regenerated at the receiver and mixed with the incoming wideband signal to recover the original data

Spread Spectrum TRADITIONAL COMMUNICATIONS SYSTEM

Slow Information

Sent

TX

Slow Information Recovered

RX

Narrowband Signal

SPREAD-SPECTRUM SYSTEM

Fast Spreading Sequence

Slow Information

Sent

TX

Slow Information Recovered

RX

Fast Spreading Sequence

Wideband Signal

WNMP WCDMA

What is Spread Spectrum?

ORIGINATING SITE DESTINATION

Spreading Sequence

Spreading Sequence

Input Data

Recovered Data

Spread Data Stream

Definition:Spread spectrum technique, employ a transmission bandwidth that is several orders of magnitude greater than the minimum required signal bandwidth.

Sender combines data with a fast spreading sequence,transmits

spread data stream

Receiver intercepts the stream,uses same spreading sequence to

extract original data

Spread signal

WNMP WCDMA

-1 1 1 -1 1 Spreading

-1 1

1 -1 1 -1

Spread Process

Digital Signal Spreading Signal

Spreading Code

1 -1 -1

WNMP WCDMA

-1 1 -1 1 -1 -1 1 1 -1 -1 1 1 -1 1 -1 1 De-

spreading

-1 1 -1 1 -1 -1 1 1

1 -1 1 -1

1 1 1 1

Integrator -4 4

0 0

Adjudge -1 1

De-spread Process

WNMP WCDMA

Illustration to SS Principle(1)

5 MHz

12.2 KHz

Power is “Spread” Over a Larger Bandwidth

WNMP WCDMA

Many code channels are individually

“spread” and then added together to

create a “composite signal”

Illustration to SS Principle(2)

WNMP WCDMA

Spread Spectrum Principles

Shannon's Formula

C=B*log2(1+S/N)

Where,

C is capacity of channel, b/s

B is signal bandwidth, Hz

S is average power for signal

N is average power for noise

In 1948 Claude Shannon published his landmark paper on information theory. A Mathematical Theory of Communication. His paper so clearly established the foundations of information theory that his framework and terminology are standard today. He died February 4, 2001 at age 84.

WNMP WCDMA

Multiple Access

• Types of Media:

– Twisted pair - copper

– Coaxial cable

– Fiber optic cable

– Air interface (radio signals)

• Advantages of Multiple Access

– Increased capacity: serve more users

– Reduced capital requirements since fewer media can carry the traffic

– Easier to manage and administer

Each pair of user

enjoys a dedicated,

private circuit through

the transmission

medium, unaware that

the other users exist.

Since the beginning of telephony and radio,

system operators have tried to squeeze the

maximum amount of traffic over each circuit.

Multiple Access: Simultaneous private use of a transmission medium by multiple independent users.

Transmission

Medium

WNMP WCDMA

Channels

• FDMA Frequency Division Multiple Access

– Each user on a different frequency

– A channel is a frequency

• TDMA Time Division Multiple Access

– Each user on a different window period in time (“time slot”)

– A channel is a specific time slot on a specific frequency

• CDMA Code Division Multiple Access

– A channel is a unique code pattern

– Each user uses the same frequency all the time, but mixed with different distinguishing code patterns

Power

Power

Power

FDMA

TDMA

CDMA

Channel: An individually-assigned, dedicated pathway through a transmission medium for one user’s information.

The transmission medium is a resource that can be subdivided into individual channels according to the technology used.

WNMP WCDMA

Physical Channels(1)

The physical channel is in a 3-layer structure by the time: – Superframe

One superframe lasts 720ms, and consists of 72 radio frames.

– radio frame

One radio frame has a period of 10ms, and comprises 15

timeslots with the same length. Corresponding to 38400

chips, it is a basic unit of the physical layer.

– Timeslot

A timeslot is a unit composed of a bit domain, corresponding

to 2560 chips. The bit number and structure of a timeslot

depends on the specific type of the physical channel.

WNMP WCDMA

Physical Channels(2)

• The frame structure of the physical channels is shown:

Tslot #1 Tslot #2 Tslot #I Tslot #15

Tslot= 2560 chip

Frame #0 Frame #1 Frame #I Frame #71

Tf=10 ms

Tsuper=720 ms

WNMP WCDMA

Key Technologies of WCDMA

• Power Control

• Handover Control

• Rake receiving

WNMP WCDMA

Why Power Control?

• All WCDMA users occupy the same frequency at the same time! Frequency and time are not used as discriminators.

• WCDMA operates by using CODES to discriminate between users.

• WCDMA interference comes mainly from nearby users

• Each user is a small voice in a roaring crowd -- but with a uniquely recoverable code.

Transmit power on all users must be tightly controlled

so their signals reach the base station at the same signal level

and at the absolute minimum power level necessary to ensure

acceptable service quality.

WNMP WCDMA

Power Control

Overcome Near-Far effect and fading compensation

ensuing network capacity

DL power control

Cell transmitting

power

Transmitting power control bit

UE signal

Power control

order

UL power control

WNMP WCDMA

Near-Far Effect

Power

f

Power

f

Nearby terminals have higher probability of success

Power control reduce the

interference among each UEs

and increase system capacity

WNMP WCDMA

3 methods of power control

Open loop: measure received signal level and

adjust transmitting power

Inner-loop: frequency 1500HZ

Measured SIR> Target SIR, lower

transmitting power

Measured SIR< Target SIR, increase

transmitting power

Outer-loop: measure FER, adjust target SIR

WNMP WCDMA

Power control

UE

RNC

Node B

Open loop power control（no feedback）

Closed loop power control（feedback）

UE Node B

RNC

Outer-loop Inner-loop

WNMP WCDMA

Power control

If received signal is stronger,then

UE can transmit lower

Node

B Node

B

1

2

1

2

PROBLEM

Assumes same exact path loss in both directions; therefore, cannot

account for asymmetrical path loss

Estimates are based on total power received

Open loop

If received signal is weaker,then UE

can transmit stronger

WNMP WCDMA

Power control

Inner-loop power control is fast

Inner-loop ：according to SIR estimation,Node-B control UE transmission

power.conducted every 0.66ms (1500Hz )

Outer-loop： according to FER measurement estimation RNC control and

adjust SIR target

Node

B

...

”Power down”

”Power up”

”Power down”

”Power ...”

SIR estimation

SIR

estimation

SIR

estimation

SIR estimation RNC SIR

target

WNMP WCDMA

The Effect of Power Control

The purpose of DL power control: Saving power resource of base station, reducing

interference to other station.

The purpose of UL power control: Overcoming Near-Far effect, received signal level

from all UEs is the same.

WNMP WCDMA

WCDMA Handoffs

During

a Call

Idle Handoff

Soft Handoff

Softer Handoff

Hard Handoff

While in the

Idle State

WNMP WCDMA

Soft/Softer Hand-off

A

B

C

A

B

C

A

B

C

A

B

C

A

B

C

A

B

C

WNMP WCDMA

Soft/Softer Hand-off

• The soft/softer handover allows to swap from one cell to another

without call interruption or without deleting all old radio links (by

opposition to hard HO).

• It also allows the UE to be connected to more than one cell

simultaneously.

Soft Handover Softer Handover

CN CN

Iur

The two Node Bs may belong to the

same RNC

The two Node Bs may belong to the

same RNC


SRNC DRNC

CN

Node B

SRNC

CN


Node B

CN

WNMP WCDMA

Hard Hand-off

• The hard handover procedure is used in case of

service quality degradation or for traffic distribution

management.

• During the hard handover procedure, all the old

radio links with the UE are abandoned before new

ones are established.

• Hard handover may occur in the following

main cases :

• When the UE is handed over another UTRAN

carrier, or technology or mode.

• When soft handover is not permitted (if O&M

constraint)

Hard Handover

Node B

SRNC

RNC or

BSC

CN

Node B

or BTS

WNMP WCDMA

Traffic control

• When traffic surpass system

threshold, traffic control

begin

• To accept as many services as

possible while keeping the

stability of the system.

WNMP WCDMA

Example for load control

• Breath effect of cell

– With the increase of activated

terminals, interference increase

– the increase of high speed service,

the increase of interference

– The shrink of cell coverage area

– Coverage blind spot occurs

– Drop of call will happen at the edge of cell

Coverage and capacity are

relative

WNMP WCDMA

Multipath Propagation

Received Signal

Time

Strength

0

Transmit

WNMP WCDMA

RAKE Receiving

d1 d2

t t t

d3

transmitting Receiving Rake

combination noise

WNMP WCDMA

RAKE Receiving

RAKE overcome multi-finger interference，improve receive capability

receiver

Single

receiving

Single

receiving

Single

receiving

searcher calculate

combining

t t

s(t) s(t)

signal

WNMP WCDMA

Coverage/capacity vs Data Rate

>12.2 kbps

>64 kbps

>384 kbps

>144 kbps

Coverage decrease

Subscriber

num

increase

Higher rate needs higher power

High data rate transmission is only available nearby the station

WNMP WCDMA

Characteristic of WCDMA system capacity

WNMP WCDMA

Coverage and Capacity

WCDMA performance is determined by such factors as： – Number of users

– Transmission rate

– Mobile rate

– Wireless enviroment

• indoors

• outdoors

The sizes of cell depend on such factors as: – Local radio conditions (local interference)

– Traffic in neighbouring cells (distanced interference)

Cell Radius decrease according to the increase number of users

WNMP WCDMA

WCDMA Overview


Advantages of WCDMA

WCDMA Architecture

Content


WNMP WCDMA

WCDMA Architecture

Iu

Iur

RNC

RNC: Radio

Network

Controller SGSN

GGSN

AuC HLR EIR

VLR

G-MSC

MSC

ce

ll ce

ll cell

ce

ll cell

ce

ll ce

ll ce

ll ce

ll

Uu

US

IM

US

IM

US

IM

FDD mode

only

UE: User

Equipment No

de B

N

od

e B

N

od

e B

RNS: Radio Network Subsystem

RNS

CN: Core Network

IuCS

IuPS Iub

G

c

Gr

Gs Gf

D

B

F C

PSTN

E E

Gi

Gn

Gp

ME

ME

ME

WNMP WCDMA

UTRAN Structure

Node B

Node B

Node B

Node B

RNC

RNC

MSC/

VLR

SGSN

U

E

U

E

IuUu

UTRANCN

Iub

RNS

RNS

Iur

WNMP WCDMA

WCDMA Architecture

• The system consists of:

– UTRAN

UTRAN performs all the functions related to wireless

communication;

– CN (Core Network)

CN switches and routes voice and data services to

connect them to the external network.

The UE (User Equipment) is connected to the

UTRAN through the air interface standard.

WNMP WCDMA

Functional Units

• UE (User Equipment):

As the wireless terminal that performs wireless

communication via the Uu interface, it contains an intelligent

card, which records the user ID, performs the authentication

algorithm, and stores information such as authentication

information and keys.

• Node B:

Transmits data streams between the Iub and the Uu

interfaces, participating in radio resource management.

WNMP WCDMA

Functional Units

• RNC (Radio Network Controller): Owns and controls the radio resources under its

administration. The RNC is the service access point

provided by the UTRAN for the CN.

• HLR (Home Location Register):

It is a database located at the local system of the user,

used to store the subscriber service features. Such features

include information of the services allowed, roaming

areas and information of value-added services.

WNMP WCDMA

Functional Units

• MSC (Mobile Switching Center) /VLR (Visit

Location Register):

The MSC processes circuit switched services, while the VLR stores a copy of the service feature description of the roaming subscribers, and more accurate information of the location of the UE in the service system.

The network part connected through the MSC/VLR is usually referred to as the CS domain.

WNMP WCDMA

Functional Units

• GMSC (Gateway Mobile-services Switching Center):

It is the switching equipment at the connection between the

UMTS network and the external circuit domain network. All incoming/outgoing CS connections go through the GMSC.

• SGSN (Serving GPRS Support Node):

Its function is similar to that of the MSC/VLR, except that

it is used for Packet Switched (PS) services. The network part connected through the SGSN is referred to as the PS domain.

• GGSN (Gateway GPRS Support Node):

Its function is similar to GMSC, but it is related to PS services.

WNMP WCDMA

Functional Units

External networks fall into two groups:

1. CS network:

It provides circuit switched connections, such as

the existing telephone services. Both ISDN and PSTN

are CS networks.

2. PS network:

It provides packet switched connections. The

Internet is an example of the PS network.

WNMP WCDMA

NE Interfaces

• Uu interface:

Serves as the air interface of the WCDMA system to

connect a UE to a Node B.

• Iu interface:

Connects the UTRAN and the CN. It is similar to the A interface (circuit switching) and the Gb interface (packet switching) in GSM.

• Iur interface:

Allows soft handover between the RNC equipment of different manufacturers as an open interface.

• Iub interface:

Connects the Node B and the RNC.

WNMP WCDMA

Brief Introduction to Node B

RNS RNS

NodeB NodeB NodeB NodeB

RNC

CN

RNC

Iu Iu

Iur

Iub Iub Iub Iub

UE

Uu

WNMP WCDMA

Brief Introduction to RNC

SRNS DRNS

NodeB NodeB NodeB NodeB

RNC

CN

RNC

Iu Iu

Iur

Iub Iub Iub Iub

UE Uu

S-RNC: Serving Radio Network Controller

D-RNC: Drifting RNC

WNMP WCDMA

Thank You

WNMP WCDMA

MSC RNC NODE B SECTOR VOCODER CARRIER TYPE of Handoff

S S S D S S Softer

S S S D S D Hard

S S D D S S Soft

S D D D D S Hard

S D D D S S Soft

S D D D D D Hard

Handoff Description

Support Slide for Handoff

200041980 basic theory wcdma v2

Documents

roadmap of wcdma

mobile network

wcdma tdscdma cdma2000

g mobile voice

broadband access

gpp 3gpp2 dect wcdmaumts

digital cellular imt

digital bearer services