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3 generation UMTS

Ae2m32mks2012 Umts

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Page 1: Ae2m32mks2012 Umts

3 generation

UMTS

Page 2: Ae2m32mks2012 Umts

2012, October, R. Bestak

History of WCDMA

• 1988: RACE I (Research of Advance Communication Techn. in Europe) Basic 3G research work (modulation, channel coding, access methods, etc.)

• 1992-1995: RACE II Development of testbeds to test in real time performance of CDMA and TDMA

• 1995: ACTS (Advanced Communication Technologies and Services) Within ACTS, a project FRAMES (Future Radio Wideband Multiple Access Sys.)

• Objective of FRAMES – defining a proposal for a UMTS radio access system

• Several partners (Nokia, Siemens, France Telecom + several European Universities)

• Results - Multiple access platform consisting of 2 modes

i) FMA1 (FRAMES Multiple Access) – based on a wideband TDMA

ii) FMA2 – based on a wideband CDMA

…submitted to ETSI as candidates for UMTS Terrestrial Radio Access

• 1997: according to the FRAMES proposals, five groups are formed in ETSI

• 1998: ETSI selects technologies for the UMTS air interface WCDMA for UMTS (FDD)

WTDMA/CDMA for (TDD)

2

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3GPP (3rd Generation Partnership Project)

• Before 3GPP - several technologies discuss/standardized around the world Waste of resource for the participating companies

Global equipment compatibility would be difficult to reach

• Creation of a single forum for WCDMA standardization 3GPP (1998) Standardization of UTRA

UMTS Terrestrial Radio Access (ETSI) Universal Terrestrial Radio Access (3GPP)

3GPP

ETSI (Europe)

ARIB (Japan)

TTA (Korea)

TTC (Japan)

CCSA (Chine)

ATIS (USA)

Partners from:

GSM association

UMTS forum,

IPv6 forum, etc.

Companies are members of 3GPP via the standardization organization

ARIB (Association for Radio Industries and Businesses)

TTC (Telecommunication Technology Committee)

TTA (Telecommunication Technology Association)

ATIS (Aliance for Telecommunication Association)

CCSA Chine Communications Standard Association

3

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3GPP (3rd Generation Partnership Project)

• Created 1998

• Association of standardization bodies & forums

ETSI (Europe), ARIB (Japan), ATIS (USA), CCSA (Chine), etc.

UMTS forum, IPv6 forum, etc.

• Specification of UMTS (…and EDGE)

• www.3gpp.org

RAN

TSG

Services and

System

Aspect TSG

CN and

Terminals

TSG

GERAN

TSG

3GPP

TSG - Technical Specification Groups

2012, October, R. Bestak 4

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2012, October, R. Bestak

Releases

• Release 99 (1999) First release

• Release 4 (2001) Minor adjustment with respect to the Release 99

• Release 5 (2002) HSDPA (High Speed Downlink Packet Access) IMS (IP Multimedia Subsystem)

• Release 6 (2004/2005) MBMS (Multimedia Broadcast/Multicast Services) HSUPA (High Speed Uplink Packet Access)

• Release 7 (2005/2006/2007) HSPA +

• Release 8 (2008) LTE (Long Term Evolution) SON (Self Organizing Network) H(e)NB

• Release 9 (2008, 2009) LTE, SON,H(e)NB

• Release 10 (2010, 2011) LTE-A (LTE- Advanced)

5

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2012, October, R. Bestak

Frequency bands (Europe)

Mode Uplink Downlink Band

UMTS-FDD 1920 - 1980 MHz 2110 - 2170 MHz 60 + 60 MHz

UMTS-TDD 1900 - 1920 MHz

2010 - 2025 MHz 20 + 15 MHz

Satellite 1980 - 2010 MHz 2170 - 2200 MHz 30 + 30 MHz

In 2000, new frequency bands 806 - 960 MHz, 1710 - 1885 MHz

2500 - 2690 MHz

The frequency bands were specified in 1992

GSMEurope

DE

CT

GSM

1800

1800 1900 2000 2100 2200 2500 2600 2700

UMTS

FDD

UM

TS

Sate

llite

UM

TS

TD

D

UM

TS

TD

D

UMTS

FDD

UM

TS

Sate

llite

UMTS

[MHz]

6

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2012, October, R. Bestak

Features

• Several simultaneous radio connections per user

• High adaptability of radio connections Setting of connections according to supported services

• Wide range of services with different QoS Voice, web, email, video/Audio streaming, etc.

…UMTS allows good support for existing and for future services

144 kbit/s 384 kbit/s 2 Mbit/s 14 Mbit/s 5,8 Mbit/s

Rural outdoor

environments

Urban outdoor

environments

Indoor and low range

outdoor environments HSDPA* HSUPA**

*HSDPA (High Speed Downlink Packet Access) **HSUPA (High Speed Uplink Packet Access)

7

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2012, October, R. Bestak

Services in 3G

• Every 3G (UMTS) service has specific requirements on Wireless delay

Bit error rate

Data rate

• Tendency Delay critical services via packet switched bearers instead of

circuit switch ones

• 4 QoS classes or traffic classes The main factor: how sensitive services are to delay

8

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2012, October, R. Bestak

QoS classes

Traffic class Conversational Streaming Interactive Background

Delay

Preserve time

relation between

information

Preserve time

relation between

information

Request response

pattern

Destination is not

expecting the data

within a certain time

<< 1 s ~ 1s < 10 s > 10 s

Tolerant to

errors Yes Yes No No

Mode Circuit switch Circuit switch

Packet switch Packet switch Packet switch

Example Voice,

Video-telephony

Streaming

multimedia

Web browsing

Database retrieval Email, SMS, MMS

9

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2012, October, R. Bestak

UMTS architecture (1/3)

• Air interface WCDMA (Wideband Code Division Multiple Access)

Radio channel 5 MHz

• New protocol on the radio interface

• Core network based on the GSM/GPRS core network

10

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2012, October, R. Bestak

UMTS architecture (2/3)

UE: User Equipment

UTRAN: UMTS Terrestrial Radio Access Network, (or RAN)

CN: Core Network

UE UTRAN CN External

Network

11

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2012, October, R. Bestak

UMTS architecture (3/3) …networks elements

UE Node B

RNC

MSC/

VLR

SGSN

Node B

HLR

GMSC

Internet

PLMN,

ISDN

UTRAN CN External Network

GGSN

UE: User Equipment MSC: Mobile Switching Centre SGSN: Serving GPRS Support Node

RNC: Radio Network Controller VLR: Visitor Location Register GMSC: Gateway MSC

HLR: Home Location Register GGSN: Gateway GPRS Support Node

UE

12

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2012, October, R. Bestak

User Equipment

• ME Radio terminal used for communication over the radio interface

• USIM ~SIM in GSM

Subscriber identity, authentication algorithm, encryption keys, etc.

USIM

ME

UE

Mobile Equipment

UMTS Subscriber

Identity Module

13

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2012, October, R. Bestak

UTRAN entities

• Node B Performs physical layer processing

(e.g., channel coding and interleaving, spreading/dispreading, rate adaptation, modulation/demodulation, or physical measurements)

Performs some basic Radio Resources Management operations (e.g., softer handover or power control)

• RNC Controls functions related to the UMTS

radio interface in its domain (e.g., admission control, radio resource control, or power control)

Manages protocol exchanges on the radio interfaces (UE-RNC, RNC-RNC or RNC-MSC/SGSN)

14

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2012, October, R. Bestak

CN entities

• HLR Stores user’s profiles (e.g., allowed services, forbidden

roaming areas or supplementary services information) + UE’s locations on the level MSC/VLR or SGSN

• MSC/VLR Circuit switched oriented services

VLR stores user’s profiles + UE’s locations

• GMSC Interface between UMTS PLMN - external CS networks

• SGSN Packet switched oriented services

• GGSN Interface between UMTS PLMN - external PS networks

15

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2012, October, R. Bestak

UMTS interfaces

UE Node B

RNC

MSC/

VLR

SGSN

Node B

HLR

GMSC

Internet

PLMN,

ISDN

GGSN

Uu Iub Iu

Iur

D

C

Gr Gc

PSTN

Gn

Gs

Iu-CS

Iu-PS

MSC/

VLR

E

16

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2012, October, R. Bestak

UTRAN evolutions

• IP transport in UTRAN (…instead of ATM)

Iur/Iub, Iu-CS

Node B RNC

UE MSC/

VLR

RNC

• Iu flex (flexible) RNC have more than one Iu-CS/Iu-PS interfaces with CN

MSC/

VLR

• HSPA HSDPA, HSUPA

17

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2012, October, R. Bestak

CN evolutions

MGM: Media Gateway MRF: Media Resource Function

HSS: Home Subscriber Server CSCF: Call Session Control Function

IMS: IP Multimedia Subsystem MGCF: Media Gateway Control Function

MGW

SGSN

MGW

GGSN

UTRAN

MSC

server

GMSC

server

Iu-CS

Iu-CS

Iu-PS

HSS

PSTN

Internet

MRF CSCF MGCF

IMS

Data & control

Control

Elements for provision

of IP multimedia services

(audio, video, chat, etc.)

delivered over the PS.

18

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2012, October, R. Bestak

Synchronous vs. asynchronous CDMA

• Synchronous Features

• Node Bs synchronized with a central clock

• GPS (cdmaOne, cdma2000) or cable

Usage • cdmaOne, cdma2000, UMTS (TDD)

Disadvantage • System deployment is more difficult

Advantage • Synchronization temporal – procedure of synchronization is simplified

• Asynchronous Features

• Node Bs transmit independently

Usage • UMTS (FDD)

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Physical layer in (w)cdma

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2012, October, R. Bestak

Spread Spectrum Techniques

• Frequency Hopping (FH)

• Direct Sequence (DS)

• Time Hoping (TH)

• Multi Carrier CDMA (MC CDMA)

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2012, October, R. Bestak

Frequency Hopping (1/3)

• The carrier frequency changes at regular time intervals

• Frequencies

Are selected from a pre-determined group within available spectrum

Change in order defined by pseudo-random sequence (with characteristics

similar to thermal noise … PN, Pseudo-Noise sequence)

Frequency

Time

f1

f2

f3

f4

f5

22

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2012, October, R. Bestak

Frequency Hopping (2/3)

Information

bits

Baseband

modulation

PN sequence

generator

Frequency

synthetizer PN sequence

generator

Frequency

synthetizer

Information

bits

Base band

demodulation

Bandbase

filter

f1 f2 f3 f4 fn

seq2 seq1 seqn seq4

f2 f1 fn f4

1

2

3

4

1

2

3 4

seq2 seq1 seqn seq4

f2 f1 fn f4

9

8

6

7

9

8

6 7

5

5

23

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2012, October, R. Bestak

Frequency Hopping (3/3)

• Tx&Rx PN sequences have to be identical + synchronized

• Depending on the hoping rate

Fast Frequency Hopping (FFH)

• hopping rate ≥ bit rate of the base band signal

Slow Frequency Hopping (SFH)

• hopping rate ≤ bit rate of the base band signal

• The higher the hopping rate & number of frequencies,

the greater privacy and interference protection

24

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2012, October, R. Bestak

Direct Sequence

• Easy implementation → mostly used … is not required a high speed frequency synthesizer

• Occupies whole available frequency band continuously

• cdma2000, WCDMA

25

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2012, October, R. Bestak

Spreading of signal

• Spreading - an information bit is processed by n consecutive bits of spreading sequence bits of Spreading sequence = chips

# of chips/per one information bit = Spreading Factor (e.g., SF= 4, 8, 16, …512)

A B AB

0 0 0

0 1 1

1 0 1

1 1 0

XOR

100 kbps (or kcps)

10 kbps 100 kbps Information

bits

Spreading

sequence

Spread

information

logical fun..XOR and analogue product

A B AB

+1 +1 +1

+1 -1 -1

-1 +1 -1

-1 -1 +1

26

Page 27: Ae2m32mks2012 Umts

2012, October, R. Bestak

Spreading/despreading

Information bits (R)

Spreading sequence (Sp)

(SF = 8)

Spread information (RSp)

(= R * Sp)

Spreading

Spreading sequence (Sp) Despreading

Data (R)

Information bit

Chip

1

-1

1

-1

1

-1

1

-1

1

-1

• RSp has the same random (pseudo-noise-like) appearance as Sp

• R * Sp widening of the occupied spectrum of the spread signal

Tx and Rx Sp

have to be identical

and synchronized

27

Page 28: Ae2m32mks2012 Umts

2012, October, R. Bestak

Direct Sequence system

Information

bits

Baseband

modulation

PN sequence

generator

PN sequence

generator

Information

bits

Baseband

demodulation

1

2

3

4

1

3

2

5

9

8

6

7

9

8

4 6

5

7

28

Page 29: Ae2m32mks2012 Umts

2012, October, R. Bestak

Processing gain (1/3)

• Despreading - strengthens the desired signal in relation to

other signals ….Processing gain (PG)

PG

SNRin SNRout(dB) = SNRin(dB) + PG(dB)

SNR - Signal to Noise Ratio

Despreading

29

Page 30: Ae2m32mks2012 Umts

2012, October, R. Bestak

Processing gain (2/3) …in Direct Sequence systems

RPN – chip rate (PN sequence rate) RInfo – information bit rate

• Example RPN = 3,84 Mcps RInfo = 12,2 kbps

PG = 10*log10(3,84*106/12,2*103) = 25 dB

• After despreading, the signal power needs to be a few dB above the interference and noise power

][log10 10 dBR

RP

R

RP

Info

PNG

Info

PNG

30

Page 31: Ae2m32mks2012 Umts

2012, October, R. Bestak

Processing gain (3/3) …in Frequency Hopping

systems

• In simple way, PG is defined as # of frequencies available for hopping

… PG increases with the number of frequencies

][log10 10 dBNPNP freqGfreqG

31

Page 32: Ae2m32mks2012 Umts

2012, October, R. Bestak

Despreading of the DS-CDMA signal

• Channels that remain spread are considered as interferes to the user and determined the SNR at the output

• Example

RPN = 3,84 Mcps RPN = 3,84 Mcps RInfo = 12,2 kbps RInfo = 2 Mbps PG = 25 dB PG = 2,8 dB

… let’s consider (for good communication) SNRout = 7 dB SNRout = SNRin + PG SNRIN = SNROUT - PG = -18 dB SNRIN = SNROUT - PG = 4,2 dB

The desired signal level can be 18 dB (4,2 dB) below (above) the interference caused by other users and noise

32

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2012, October, R. Bestak

Spreading codes

• Features Influence interference among users

Have to have random behavior

• Choice according to Auto-correlation features

Cross-correlation features

• Types of codes PN sequence (Pseudo random Noise sequence)

• MLS (Maximal Length Sequence)

Gold code

Walsh code

33

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2012, October, R. Bestak

Auto-Correlation Function (1/2)

Similarity between a function F(t) and

itself at different time (phase offset) dttFtFACF

)()(

• ACF of bit sequence

→ bit-by-bit comparison of a sequence

(length L) with the shift version of itself

(offset from 1 to L)

NCCCCACF

# Coinciding bits between sequences

# Non-Coinciding bits between sequences

34

Page 35: Ae2m32mks2012 Umts

2012, October, R. Bestak

Auto-Correlation Function (2/2)

-2

0

2

4

6

8

Phase offset

(bits) Sequence phase CC NCC ACF

0 1011100 7 0 7

1 0111001 3 4 -1

2 1110010 3 4 -1

3 1100101 3 4 -1

4 1001011 3 4 -1

5 0010111 3 4 -1

6 0101110 3 4 -1

7 1011100 7 0 7

• The max. of ACF is every

time, when both compared

sequences have the same

phase offset.

Corr

ela

tion

PN offset

04 05 06 00 01 02 03 04 05 06 00 01 02 03

35

Page 36: Ae2m32mks2012 Umts

2012, October, R. Bestak

Auto-Correlation features of codes

• Important role in the synchronization process

• 2 steps in synchronization:

Acquisition

• Tries to achieve code alignment of locally generated and received

sequences by shifting the locally generated sequence

Tracking

• Maintains the correct alignment

36

Page 37: Ae2m32mks2012 Umts

2012, October, R. Bestak

Cross-Correlation Function

similarity between functions F(t) and G(t) taken with a time difference between them

dttGtFCCF

)()(

• CCF of bit sequence

→ bit-by-bit comparison of sequences F(t)

and G(t), with the same length L

NCCCCCCF

# Coinciding bits between sequences

# Non-Coinciding bits between sequences

• Orthogonal codes: CCF = 0

37

Page 38: Ae2m32mks2012 Umts

2012, October, R. Bestak

Codes in UMTS (1/5) …downlink

User data

Si

Channelization code

(Walsh)

Symbol rate

(variable)

Chip rate

(fix)

• Spreading codes = Walsh codes

Each code represents one channel channelisation codes

Identify users in the cell

Code length is variable and depends on services

Ci

Ci+1

Si+1

Ck

Sk

38

Page 39: Ae2m32mks2012 Umts

2012, October, R. Bestak

Codes in UMTS (2/5) …downlink

• Scrambling: multiplication of spread sequence by a second sequence

Used on the top of spreading

No change of the signal bandwidth (… no change of the rate)

• Scrambling codes = Gold codes

Improves auto-correlation features of Channelization codes

Identifies Node Bs (… to each Node B is assigned different code)

Scrambling code

(Gold)

Chip rate

User data

Si

Channelization code

(Walsh)

Symbol rate

(variable)

Chip rate

(fix)

Ci

Ci+1

Si+1

Ck

Sk

39

Page 40: Ae2m32mks2012 Umts

2012, October, R. Bestak

Codes in UMTS (3/5) …downlink

• Node B

Transmitted signals from Node B are synchronized in time

• UE (…reception)

Due to multi-path propagation, the orthogonal feature of

transmitted signals get break

40

Page 41: Ae2m32mks2012 Umts

2012, October, R. Bestak

Codes in UMTS (4/5) …uplink

• Channelisation code Walsh

Separation of physical data and control channels

• Scrambling code Short (Gold) or Long (PN sequences)

Separation of users

• User’s signals are not orthogonal Transmitted signals from UEs are asynchronous

41

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2012, October, R. Bestak

Codes in UMTS (5/5)

Channelisation code Scrambling code

Use

Downlink: separation of UE within one cell

Uplink: separation of physical/control ch.

from same UE

Downlink: separation of cells

Uplink: separation of UE

Chip length Downlink: 4-512 chips

Uplink: 4-256 chips

Downlink: 10 ms = 38400 chips

Uplink: 10 ms = 38400 chips or

66,7 µs = 256 chips

Number of

codes # of codes under one scrambling code = SF

Downlink: 512

Uplink: several millions

Bandwidth Increase transmission bandwidth Does not affect transmission bandwidth

42

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Radio resource management

Page 44: Ae2m32mks2012 Umts

2012, October, R. Bestak

Radio Resource Management (RRM)

• RRM

Responsible for efficient utilization of the radio resources

• RRM is needed to

Guarantee QoS

Maintain the planned coverage area

Offer high capacity

• Type of RRM algorithms

Power control

Handover

Admission control, etc.

44

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2012, October, R. Bestak

Power control (1/2)

• number of active UE = level of interference in the system

A UE generates interference

a) To all other UEs within the same cell

b) To all UEs in neighbor cells

• UE transmission power = interference (system capacity)

45

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2012, October, R. Bestak

Power control (2/2) …near-far problem in cdma

UE2 UE1

Node B

• Tight & fast power control is one of the most important aspect in cdma system

• A single overpowered UE

could block a large part of

the cell

Near-far problem

Power control → minimize interference and thus increase the system capacity

46

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2012, October, R. Bestak

Fast closed-loop power control

• Uplink Node B measures the received SIR (Signal to Interference Ratio)

IF SIRmeasured > SIRtarget then Node B command the UE to power IF SIRmeasured < SIRtarget then Node B command the UE to power

Rate 1 commands/slots, i.e. 1500/s (1500Hz) • In GSM - slow power control, 2 Hz

• Mechanism operates faster than any significant path loss change could occur

Basic step 1dB/slot • …eventually 2dB/slot (30dB correction within 10 ms frame)

• Smaller step sizes are emulated (0,5dB = 1dB/2 slots …)

… UE in a deep fade causes increased inference to other cell (high tx power)

• Downlink No near-far problem (…scenario one Node B to many UEs)

Node B increases the power of signal belonging to UEs at the cell edge

UE2 UE1

Node B Power command

tx power Power command

tx power

47

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2012, October, R. Bestak

Open loop power control

• Rough initial power setting of the UE

Downlink beacon signal is used for the setting

Setting is very inaccurate

• Fast fading is uncorrelated between uplink & downlink

• Large frequency separation of uplink and downlink band

48

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2012, October, R. Bestak

Outer loop power control

• SIRtarget is set according to required BER or BlER (e.g.,BlER = 1%)

• SIRtarget = f (speed of UE) … change of UE speed ≈ change of BER

SIRtarget has to be change according to the UE speed

• Outer loop power control SIRtarget (in Node B) is adjusted to keep a constant quality, i.e. BER

RNC

(Outer loop power control)

Node B

(Fast closed power control) UE

Frame reliability info

SIRtarget adjustment

commands

SIRtarget

Time

49

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2012, October, R. Bestak

Handover

• Handover, or Hand-off (Handoff)

• Allow mobility of UEs between cells by changing the

communication radio channel

• Types

Hard handover

Soft handover

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Hard handover

BTS 1

(F1,TS5)

BTS 2 BTS 1

(F2,TS3)

BTS 2

MSa MSa

• A MS communicates simultaneously with just one BTS

• A MS may experience a brief interruption in the connection when switching from the old channel to the new one

(e.g., GSM)

51

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2012, October, R. Bestak

Soft handover … general

• CDMA systems

• UE communicates with two or more Node Bs simultaneously

A UE starts communication with a Node B2 while still connected to the Node B1

Seamless transmission between cells

• Several simultaneous connections to different Node Bs → Macro-diversity

Node B1 Node B2

1

UEa Node B1

Node B2

2

UEa

Node B1

Node B2

UEa

Node B3

52

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2012, October, R. Bestak

Soft vs. softer handover

• Soft UE is located in a coverage are of 2

different Node Bs • Communication UE/Node B takes

place via 2 radio channels

• Combination of signals (uplink) is realized in the RNC

Two power control loops per connection are active

Sector 1

Sector 2

RNC

Node B

1

UEa

Node B2

Sector 1

Sector 2

RNC Node B

UEa

• Softer UE is located in a coverage are of 2

sectors of the same Node B • Communication UE/Node B takes place

via 2 radio channels

• Combination of signals (uplink) is realized in the Node B

One power control loop per connection is active

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Transport and physical channels

Page 55: Ae2m32mks2012 Umts

2012, October, R. Bestak

Protocol architecture

PDCP: Packet Data Convergence Protocol BMC: Broadcast/Multicats Control Protocol

User plane

Medium Access Control (MAC)

Physical Layer (PHY)

BMC PDCP

Radio Resource

Control

Radio Link Control (RLC)

Control plane

contr

ol

Layer 3

Layer 2

Layer 1

Transport channels

Logical channels

Physical channels

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Transport channels

• DCH: Dedicated Ch.

• E-DCH: Enhanced DCH

• BCH: Broadcast Ch.

Transport channels

Dedicated transport ch. Common transport channels

DCH (Up/Down)

E-DCH (Up)

BCH (Down)

FACH (Down)

PCH (Down)

RACH (Up)

HS-DSCH (Down)

DSCH (Down)

CPCH (Up)

• CPCH: Common Packet Ch.

• DSCH: Downlink Shared Ch.

• HS-DSCH: High Speed DSCH

• PCH: Paging Ch.

• FACH: Forward Access Ch.

• RACH: Random Access Ch.

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Common transport channel

• Broadcast Ch. (BCH) Info specific to UTRA network or cell (random access codes, access slots, etc.)

• Paging Ch. (PCH) Info relevant to the paging procedure (call to the UE)

• Forward Access Ch. (FACH) Signaling (eventually + small amount of packet data)

1 or more FACH/cell (at least 1 channel with a low rate)

• Downlink Shared Ch. (DSCH) Packet data and/or signaling

Associated with DCH

… DCH gives power control info, info when to decode DSCH and which spreading code to use

• High Speed DSCH (HS-DSCH) Packet data and/or signaling

Associated with DCH

• Random Access Channel (RACH) Signaling eventually + small amount of packet data (1-2 frames)

(Signaling – registration of UEs to the network, location update when moving from one location area to another, initialization of a call)

• Uplink Common Packet Channel (CPCH) …Extension of RACH (…higher amount of packet data - several frames)

57

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Transport channels …features

Type Channel Direction

Fast power

control / soft

handover

Coverage of

whole cell

TTI

(ms) Data Notes

Dedicated DCH

Downlink

Uplink Yes / Yes

Yes (or part of it) (beam-forming ant.)

10-80 Yes

E-DCH Uplink Yes /Yes Yes 10 Yes HSUPA (Rel 6)

Common

BCH Downlink No Yes 20 No Low bit

rate channel PCH Downlink No Yes 10 No

FACH Downlink No / No

(Slow power control

or no power control)

Yes Small amount 1 or x Chs/cell

DSCH Downlink Yes / No No 10 Yes Rel99

HS-DSCH Downlink No /No No 2 Yes HSDPA (Rel 5)

RACH Uplink No / No No 10,20 Small amount Slotted ALOHA

CPCH Uplink Yes / No Yes Small/medium

amount

Fast setup/release

channel

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Physical channels …mapping

DCH (Down/Up)

E-DCH (Up)

BCH (Down)

FACH (Down)

PCH (Down)

RACH (Up)

HS-DSCH (Down)

DSCH (Down)

CPCH (Up)

SCH (Synchronization Ch.)

CPICH (Common Pilot Ch.)

AICH (Acquisition Indication Ch.)

PICH (Paging Indication Ch.)

CPCH (CPCH Status Indication Ch.)

CD/CA-ICH (Collision Detection/Channel Assignment Indicator Ch.)

DPDCH (Dedicated Physical Data Ch.)

DPCCH (Dedicated Physical Control Ch.)

PCCPCH (Primary Common Control Physical Ch.)

SCCPCH (Secondary Common Control Physical Ch.)

PDSCH (Physical Downlink Shared Ch.)

PRACH (Physical Random Access Ch.)

PCPCH (Physical Common Packet Ch.)

HS-PDSCH (High Speed PDSCH) HS-SCCH (HS Shared Control Ch.), HS-DPCCH (HS DPCCH)

E-DPDCH, E-DPCCH: Enhanced DPDCH, DPCCH E-AGCH (E-DCH Absolute Grant Ch.), E-RGCH (E-DCH Relative Grant Ch.),

E-HICH (E-DCH Hybrid ARQ Indicator Ch.)

Signaling

physical channels

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Physical channels

• Defined by Frequency

Channelisation code

Time duration

• Structure of radio frame 38400 chips

Duration 10 ms

15 slots • 2560 chips/slot

• 666 μs/slot (…GSM - 577 μs/slot)

0 1 2 3 4 5 6 7 … 13 14

Radio frame = 10 ms (38400 chips)

slot

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Uplink dedicated channel …DPDCH,DPCCH

• DPDataCH Data of DCH transport channels

0, 1 or several channels/radio link (…useful to use 1 ch. as long as possible multicode transm. = reduction of amplifier efficiency

Variable SF, data rate can vary from frame to frame

• DPControlCH Control physical layer info (Transmission Power Control TPC, TFCI, Ch. estimation, Feedback etc.)

1 channel on radio/radio link

Fix SF

0 1 2 3 4 5 6 7 … 13 14

Radio frame = 10 ms (38400 chips)

DPDataCH (SF = 4 256)

1slot (2560 hips)

DPControlCH (SF = 256)

SF Bits/Slot Bits/Frame Channel bit

rate (kbps)

256 10 150 15

:

8 320 4800 480

4 640 9600 960

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Downlink dedicated channel …DPCH

• Dedicated Physical Channel (DPCH) DPDCH (…data)

DPCCH (…control)

• Time multiplexing of DPDCH and DPCCH

0 1 2 3 4 5 6 7 … 13 14

Radio frame = 10 ms (38400 chips)

1slot (2560 hips)

SF Bits/Slot Data1, Data2

(bits)

TPC, TFCI,

Ch. est (bits)

Channel bit

rate (kbps)

512 10 0, 4 2, 0, 4 15

:

8 320 56, 232 8, 8, 16 480

4 1280 248, 1000 8, 8, 16 1920

Data1 TPC TFCI Data2 Ch.estimation

DPDCH DPCCH DPCCH DPDCH DPCCH

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Uplink random channel …PRACH

#1 #2 #3 #4 #5 #6 #7 #8 #0 #11 #12 #13 #14 #9 #10

5120 chips

Random Access Transmission

Random Access Transmission

Random Access Transmission

Random Access Transmission

Radio frame, 10 ms Radio frame, 10 ms

UE starts the random-access transmission at the beginning of well-defined time intervals - access slots (15 access slots / 2 frames)

Preamble Preamble Preamble …

4096 chips

Message part

10 ms (1 radio frame) or

20 ms(2 radio frame)

Preamble detected and Ack via AICH

SF = 256…32 (15…120 kbits)

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Access procedure (RACH)

1. UE decodes BCH (to find out the available RACH sub-channels/access slots and their scrambling codes and signatures)

2. UE randomly select 1 RACH access slot and 1 available signature

3. UE sets the initial tx power according to the downlink measurements (loop power control …inaccurate)

4. UE transmits RACH preamble (with the selected signature)

5. UE decodes AICH to see if the Node B detected the preamble If yes UE transmits the RACH message part (10 or 20 ms)

else UE increases the tx power about one step (+1dB) and retransmits the preamble in the next available access slot

AICH (preamble)

RACH (preamble)

RACH (preamble)

RACH (message)

AICH

RACH

1 or 2 frames

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Access procedure (CPCH)

• CPCH procedure is similar to RACH one, but CPCH uses detection of collision

• Phases 1. to 5. …same as RACH procedure

6. UE sends a CD preamble with the same power, but with another available signature,

7. Node B echoes the CD preamble back

8. After receiving the echoed CD preamble, UE starts the transmission

AP-AICH (preamble)

CPCH (preamble)

CPCH (preamble)

CPCH

transmission

AP-AICH

CPCH CPCH

(CD pream.)

CD-ICH (CD pream.) CD-ICH

• Status monitoring & channel assignment CSICH: status indication of CPCHs (this avoid unnecessary access attempts if all CPCHs are busy)

CD-ICH: information for UEs about a CPCH channel assignment (CA is sent in parallel with CD)

Several frames (max. # of frames is set by UTRAN

during services negotiation)

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Paging procedure

• If a paging message appear for any UE of the paging group, PI periodically appears on PICH

• Once the UE detects PI, the UE decodes the next PCH frame (Secondary CCPCH) to see whether if there is a paging message intended for it

UEGP1

UEGP1

UEGP1

UEGP2

UEGP2 UEGP1

UEGP1

UEGP2 UEGP2

Every UE is

assigned to a

paging group

The less often the PIs appear, the less often the UE wakes up from the sleep mode

→ the longer the battery life becomes

Node B

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Protocol architecture of UTRAN

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Protocol architecture (1/2)

PDCP: Packet Data Convergence Protocol BMC: Broadcast/Multicats Control Protocol

User plane

Medium Access Control (MAC)

Physical Layer (PHY)

BMC PDCP

Radio Resource

Control

Radio Link Control (RLC)

Control plane

contr

ol

Layer 3

Layer 2

Layer 1

Transport channels

Logical channels

Physical channels

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Protocol architecture (2/2)

Node B RNC

UE

MAC

RLC

RRC

Phy

MAC

RLC

RRC

Phy

PDCP PDCP BMC BMC

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Data transmission in UMTS

MAC

Phy

MAC

PDCP

IP

PDCP

IP IP

Proxy Radio Access Network

Core

Networks +

Internet

Phy

RLC RLC

RNC NodeB UE

TCP TCP

Server

AI

RR

C

RR

C

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MAC

• Medium Access Control

• Functions Mapping

• Logical channels Transport channels

Multiplexing/Demultiplexing • RLC blocks transport blocks

Priority handling (scheduling)

Traffic measurement

...

User plane

BMC PDCP

RRC

Control plane

MAC

RLC

PHY

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MAC …entities

MAC entity Transport channel Release

MAC-b Broadcast ch. BCH (Broadcast channel) Rel’99

MAC-c/sh/m Common ch. PCH (Paging channel)

FACH (Forward Access channel)

RACH (Random Access channel)

DSCH (Downlink Shared channel)

USCH (Uplink Shared channel)

Rel’99

MAC-d Dedicated ch. DCH (Dedicated channel) Rel’99

MAC-hs HSDPA HS-DSCH (HS Downlink Shared channel) Rel’5

MAC-e/es HSUPA E-DCH (Enhanced Dedicated channel) Rel’6

MAC-m Common ch. FACH (Forward Access channel) …MBMS* Rel’6

*MBMS – Multimedia Broadcast Multicast Service

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MAC …entities - UE

Associated

Downlink

Signalling

E-DCH

MAC-d

FACH

RACH

DCCH DTCH DTCH

DCH DCH

MAC Control

USCH ( TDD only )

CTCH BCCH CCCH SHCCH ( TDD only )

PCCH

PCH

MAC-hs

HS-DSCH

Associated

Uplink

Signalling

Associated

Downlink

Signalling

MAC-es /

MAC-e

Associated

Uplink

Signalling

MAC-m

MTCH MSCH MTCH MSCH

MCCH

FACH

MAC-c/sh/m

FACH USCH ( TDD only )

DSCH ( TDD only )

DSCH ( TDD only )

HSUPA

HSDPA

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MAC …entities - UTRAN

FACH RACH

DCCH DTCH DTCH

DSCHTDD only

MAC Control

Iur or local

MAC Control

DCH DCH

MAC-d

USCH TDD only

MAC-c/sh/m

CCCH CTCH

BCCH

SHCCH TDD only

PCCH

FACH PCH USCH TDD only

DSCHTDD only

MAC Control

HS-DSCH HS-DSCH

Associated Uplink

Signalling Associated Downlink

Signalling

MAC-hs

Configuration

without MAC -c/sh Configuration

with MAC

Configuration

with MAC-c/sh

E-DCH

Associated Uplink

Signalling Associated Downlink

Signalling

MAC Control

MAC-es

MAC-e

MAC Control

Iub

c/sh

MSCH

MTCHMCCH

Node B RNC

HSUPA HSDPA

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RLC

• Radio Link Control

• Functions

Segmentation/Reassembly

• Upper layer blocs RLC blocks

Error corrections (ARQ)

Flow control

In-sequence delivery to upper layer

Ciphering

User plane

BMC PDCP

RRC

Control plane

MAC

RLC

PHY

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PDCP

• Packet Data Convergence Protocol

• Functions

Compression (decompression)

of headers

User plane

BMC PDCP

RRC

Control plane

MAC

RLC

PHY

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BMC

• Broadcast/Multicast Control protocol

• Functions

Scheduling of BMC messages

Transmission of BMC messages to UEs

...

User plane

BMC PDCP

RRC

Control plane

MAC

RLC

PHY

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RRC

• Radio Resource Control protocol

• Control plane

• RRC units Signaling of RRC

Signaling of upper layer

• Functions Establishment/maintenance/release RRC conn.

Power control

User plane

BMC PDCP

RRC

Control plane

MAC

RLC

PHY

2012, October, R. Bestak 78