WCDMA System Architecture 3G WCDMA Cellular Network

WCDMA System Architecture

3G WCDMA Cellular Network

1

Network Elements in a WCDMA PLMN

•PLMN: Public Land Mobile Network. •One PLMN is operated by a single operator.

WCDMA System Architecture
WCDMA/UMTS system utilizes the same well-known architecture that has been used by all main 2nd generation systems. The network elements are grouped into:
the Radio Access Network (RAN, UMTS Terrestrial RAN = UTRAN) that handles all radio-related functionality. The Core Network (CN) which is responsible for switching and routing calls and data connections to external networks.

Both User Equipment (UE) and UTRAN consist of completely new protocols, which is based on the new WCDMA radio technology. The definition of CN is adopted from GSM.

2

Classified transport channel
Dedicated transport channel
Identified by a certain code in a certain frequency reserved for a single user only

Common transport channel
Used by all or a group of user on a cell

Dedicated transport channel (DCH)

The dedicated channel is a downlink or uplink transport channel.

3

Common transport channels
There are six types of common transport channels: BCH(broadcast channel) FACH(forward access channel) PCH(paging channel) RACH(random access channel) CPCH(common packet channel) DSCH(downlink shared channel)

Mapping of transport channel onto physical channels
Transport Channels Physical Channels DCH Dedicated Physical Data Channel (DPDCH) Dedicated Physical Control Channel (DPCCH) RACH Physical Random Access Channel (PRACH) CPCH Physical Common Packet Channel (PCPCH) Common Pilot Channel (CPICH) BCH Primary Common Control Physical Channel (P-CCPCH) FACH Secondary Common Control Physical Channel (S-CCPCH) PCH Synchronisation Channel (SCH) DSCH Physical Downlink Shared Channel (PDSCH)

4

Mapping of transport channel onto physical channels (continued)

Transport Channels Physical Channels Acquisition Indicator Channel (AICH) Access Preamble Acquisition Indicator Channel (AP-AICH) Paging Indicator Channel (PICH) CPCH Status Indicator Channel (CSICH) Collision-Detection/Channel-Assignment Indicator Channel (CD/CA-ICH)

Uplink physical channelchannels Dedicated uplink physical
DPCCH DPDCH

Common uplink physical channels
PRACH PCPCH

5

Downlink physical channels
CPICH P-CCPCH S-CCPCH SCH PDSCH AICH

Dedicated downlink physical channel Common downlink physical channel

Downlink physical channel (continued)
CD/CAICH PICH CSICH

6

Uplink frame format
Dedicated channel frame
DPDCH Data N data bits T slot = 2560 chips, N data = 10*2 k bits (k=0..6) DPCCH Pilot Npilot bits TFCI NTFCI bits T slot = 2560 chips, 10 bits FBI NFBI bits TPC NTPC bits

Slot #0

Slot #1

Slot #i 1 radio frame: T f = 10 ms

Slot #14

Uplink frame format
PRACH frame
Data Pilot Npilot bits Tslot = 2560 chips, 10*2k bits (k=0..3) Data Ndata bits TFCI NTFCI bits

Control

Slot #0

Slot #1

Slot #i Message part radio frame TRACH = 10 ms

Slot #14

7

Uplink frame format
PCPCH frame
Data Pilot Npilot bits Data Ndata bits TFCI NTFCI bits FBI NFBI bits TPC NTPC bits

Control

Tslot = 2560 chips, 10*2k bits (k=0..6)

Slot #0

Slot #1

Slot #i 1 radio frame: Tf = 10 ms

Slot #14

Uplink multiplexing
a
im 1

, a

im

2

, a

im

3

, K

, a

imA

i

C

R

C

a t t a c h m

e n t

b

im

1

, b

im

2

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im

3

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C

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T

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i

r B k c o n c a t e n a t i o n / o d e b l o c k s e g m e n t a t i o n

o

ir

1

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2

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3

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i

C

h a n n e l

c o d i n g

c

i 1

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R

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i

a d i o

f r a m

e

e q u a l i s a t i o n

t

i 1

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i 2

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1

s t

i n t e r l e a v i n g

d

i 1

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R

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f r a m

e

s e g m

e n t a t i o n

e

i 1

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a t e

m

a t c h i n g

m

R a t e a t c h i n g

f

i 1

,

f

i 2

,

f

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,

f

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i

T

r C

H

M

u l t i p l e x i n g C C T r C H

s

1

, s

2

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3

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S

u

p 1

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p

2

p

3

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P h y s i c a l c h a n n e l s e g m e n t a t i o n

, u

pU

2

n d

i n t e r l e a v i n g

v

p 1

, v

p

2

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p

3

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pU

P h y s i c a l

c h a n n e l

m

a p p i n g

PhCH#1

PhCH#2

8

Downlink frame format
dedicated physical frame
DPDCH Data1 Ndata1 bits DPCCH TPC NTPC bits TFCI NTFCI bits DPDCH Data2 Ndata2 bits DPCCH Pilot Npilot bits

Tslot = 2560 chips, 10*2k bits (k=0..7)

Slot #0

Slot #1

Slot #i One radio frame, Tf = 10 ms

Slot #14

Downlink multiplexing
a
im 1

, a

im

2

, a

im

3

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, a

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C

R
i

C

a t t a c h m

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b

im

1

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im

2

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im

3

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C

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T

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o

ir

1

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2

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3

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r B k c o n c a t e n a t i o n / o d e b l o c k s e g m e n t a t i o n
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i

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h a n n e l

c o d i n g

c

i 1

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a t e

m

a t c h i n

g

m

R a t e a t c h i n g

g

i 1

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g

i 2

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g

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,

g

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h

i 1

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T

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w

1

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i n s e r t i o n o f i n d i c a t i o n

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T

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P

u

p 1

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p

2

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2

n

d

i n t e r l e a v i n g

v

p 1

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p

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p

3

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s i c a l

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PhCH#2

PhCH#1

9

Uplink spreading(PRACH)
cd,1 βd DPDCH1 cd,3 DPDCH3 cd,5 DPDCH5 βd βd

Σ

I

Sdpch,n I+jQ cd,2 βd S

DPDCH2 cd,4 DPDCH4 cd,6 DPDCH6 cc DPCCH βc βd βd

Σ

Q

j

Uplink spreading(PRACH)
cd PRACH message data part PRACH message control part cc βc βd Sr-msg,n I I+jQ Q S

j

10

Uplink spreading(PCPCH)
cd PCPCH message data part PCPCH message control part cc βc βd Sc-msg,n I I+jQ Q S

j

Uplink modulation
cos(ωt) Re{S} Complex-valued chip sequence from spreading operations S Split real & imag. parts Pulseshaping Pulseshaping -sin(ωt)

Im{S}

11

Downlink spreading(expect SCH)
I Any downlink physical channel except SCH

S → P

Sdl,n I+jQ S

Cch,SF,m Q

j

Downlink spreading
Different downlink Physical channels (point S ) G1

G2

Σ
P-SCH GP S-SCH GS

Σ

(point T )

12

Downlink modulation
cos(ωt) Re{S} Complex-valued chip sequence from spreading operations S Split real & imag. parts Pulseshaping Pulseshaping -sin(ωt)

Im{S}

13