Post on 21-Jul-2016
description
www.huawei.com
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.
WCDMA Radio Interface Physical Layer
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page1
Foreword
The physical layer offers data transport services to higher
layers.
The physical layer is expected to perform the following
functions in order to provide the data transport service, for
example: spreading, modulation and demodulation,
despreading, Inner-loop power control and etc.
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page2
Objectives
Upon completion of this course, you will be able to:
Outline radio interface protocol Architecture
Describe structure and functions of different physical
channels
Describe UMTS physical layer procedures
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page3
Contents
1. Physical Layer Overview
2. Physical Channels
3. Physical Layer Procedure
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page4
Contents
1. Physical Layer Overview
2. Physical Channels
3. Physical Layer Procedure
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page5
UTRAN Network Structure
RNS
RNC
RNS
RNC
Core Network
NodeB NodeB NodeB NodeB
Iu-CS Iu-PS
Iur
Iub Iub Iub Iub
CN
UTRAN
UE Uu
CS PS
Iu-CS Iu-PS
CS PS
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page6
Uu Interface Protocol Structure
L3
co
ntr
ol
co
ntr
ol
co
ntr
ol
co
ntr
ol
C-plane signaling U-plane information
PHY
L2/MAC
L1
RLC
DC Nt GC
L2/RLC
MAC
RLC RLC
RLC
Duplication avoidance
UuS boundary
L2/BMC
control
PDCP PDCP L2/PDCP
DC Nt GC
RRC
RLC RLC
RLC RLC
BMC
radio bearer
logical channel
transport channel
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page13
RAB, RB and RL
RAB
RB
RL NodeB
RNC CN UE
UTRAN
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page14
Contents
1. Physical Layer Overview
2. Physical Channels
3. Physical Layer Procedure
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page15
Contents
2. Physical Channels
2.1 Physical Channel Structure and Functions
2.2 Channel Mapping
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page16
WCDMA Radio Interface Channel Definition
Logical Channel = information container
Defined by <What type of information> is transferred
Transport Channel = characteristics of transmission
Described by <How> and with <What characteristics> data
is transmitted over the radio interface
Physical Channel = specification of the information global
content
providing the real transmission resource, maybe a
frequency , a specific set of codes and phase
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page17
Logical Channel
Control channel
Traffic channel
Dedicated traffic channel (DTCH)
Common traffic channel (CTCH)
Broadcast control channel (BCCH)
Paging control channel (PCCH)
Dedicate control channel (DCCH)
Common control channel (CCCH)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page20
Transport Channel
Dedicated Channel (DCH)
Broadcast channel (BCH)
Forward access channel
(FACH)
Paging channel (PCH)
Random access channel (RACH)
High-speed downlink shared
channel
(HS-DSCH)
Common transport
channel
Dedicated transport
channel
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page21
Physical Channel
A physical channel is defined by a specific carrier frequency,
code (scrambling code, spreading code) and relative phase.
In UMTS system, the different code (scrambling code or
spreading code) can distinguish the channels.
Most channels consist of radio frames and time slots, and each
radio frame consists of 15 time slots.
Two types of physical channel: UL and DL
Physical Channel
Frequency, Code, Phase
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page22
Downlink Physical Channel
Downlink Dedicated Physical Channel (DL DPCH)
Downlink Common Physical Channel
Primary Common Control Physical Channel (P-CCPCH)
Secondary Common Control Physical Channel (S-CCPCH)
Synchronization Channel (SCH)
Paging Indicator Channel (PICH)
Acquisition Indicator Channel (AICH)
Common Pilot Channel (CPICH)
High-Speed Physical Downlink Shared Channel (HS-PDSCH)
High-Speed Shared Control Channel (HS-SCCH)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page23
Uplink Physical Channel
Uplink Dedicated Physical Channel
Uplink Dedicated Physical Data Channel (Uplink DPDCH)
Uplink Dedicated Physical Control Channel (Uplink DPCCH)
High-Speed Dedicated Physical Channel (HS-DPCCH)
Uplink Common Physical Channel
Physical Random Access Channel (PRACH)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page24
Function of Physical Channel
NodeB
UE
P-CCPCH-Primary Common Control Physical Channel
P-CPICH--Primary Common Pilot Channel
SCH--Synchronisation Channel
Cell Search Channels
DPDCH--Dedicated Physical Data Channel
DPCCH--Dedicated Physical Control Channel
Dedicated Channels
Paging Channels
PICH--Paging Indicator Channel
SCCPCH--Secondary Common Control Physical
Channel
PRACH--Physical Random Access Channel
AICH--Acquisition Indicator Channel
Random Access Channels
HS-DPCCH--High Speed Dedicated Physical Control
Channel
HS-SCCH--High Speed Share Control Channel HS-PDSCH--High Speed Physical Downlink Share
Channel
High Speed Downlink Share Channels
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page25
Synchronization Channels (P-SCH & S-SCH) Used for cell search
Two sub channels: P-SCH and S-SCH
SCH is transmitted at the first 256
chips of every time slot
Primary synchronization code is
transmitted repeatedly in each time
slot
Secondary synchronization code
specifies the scrambling code groups
of the cell
Primary
SCH
Secondary
SCH
Slot #0 Slot #1 Slot #14
ac s i,0
p ac p ac p ac
ac s i,1 ac s
i,14
256 chips
2560 chips
One 10 ms SCH radio frame
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page26
Secondary Synchronization Channel (S-SCH)
slot number Scrambling Code Group #0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14
Group 0 1 1 2 8 9 10 15 8 10 16 2 7 15 7 16
Group 1 1 1 5 16 7 3 14 16 3 10 5 12 14 12 10
Group 2 1 2 1 15 5 5 12 16 6 11 2 16 11 15 12
Group 3 1 2 3 1 8 6 5 2 5 8 4 4 6 3 7
Group 4 1 2 16 6 6 11 15 5 12 1 15 12 16 11 2
…
Group 61 9 10 13 10 11 15 15 9 16 12 14 13 16 14 11
Group 62 9 11 12 15 12 9 13 13 11 14 10 16 15 14 16
Group 63 9 12 10 15 13 14 9 14 15 11 11 13 12 16 10
…….. acp
Slot # ?
P-SCH acp
Slot #?
16 6 S-SCH
acp
Slot #?
11 Group 2
Slot 7, 8, 9 256 chips
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page27
Primary Common Pilot Channel (PCPICH)
Primary CPICH
Carrying pre-defined sequence
Fixed channel code: Cch, 256, 0, Fixed rate 30Kbps
Scrambled by the primary scrambling code
Broadcast over the entire cell
A phase reference for SCH, Primary CCPCH, AICH, PICH and
downlink DPCH, Only one PCPICH per cell
Pre-defined symbol sequence
Slot #0 Slot #1 Slot # i Slot #14
Tslot = 2560 chips , 20 bits
1 radio frame: Tr = 10 ms
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page28
Primary Common Control Physical Channel (PCCPCH)
Carrying BCH transport channel
Fixed rate, fixed OVSF code (30kbps,Cch, 256, 1)
The PCCPCH is not transmitted during the first 256 chips of
each time slot
PCCPCH Data
18 bits
Slot #0
1 radio frame: T f = 10 ms
Slot #1 Slot #i
256 chips
Slot #14
T slot
= 2560 chips,20 bits
SCH
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page29
Paging Indicator Channel (PICH)
Carrying Paging Indicators (PI)
Fixed rate (30kbps), SF = 256
N paging indicators {PI0, …, PIN-1} in each PICH frame, N=18, 36,
72, or 144
One radio frame (10 ms)
b 1 b 0
288 bits for paging indication 12 bits (undefined)
b 287 b 288 b 299
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page30
Secondary Common Control Physical Channel (SCCPCH)
Carrying FACH and PCH, SF = 256 - 4
Pilot: used for demodulation
TFCI: Transport Format Combination Indication, used for describe
data format
Data
N bits
Slot #0 Slot #1 Slot #i Slot #14
1 radio frame: T f = 10 ms
T slot = 2560 chips,
Data
Pilot
N bits Pilot N bits TFCI
TFCI
20*2 k bits (k=0..6)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page31
Physical Random Access Channel (PRACH)
Carrying uplink signaling and data, consist of two parts:
One or several preambles: 16 kinds of available preambles
10 or 20ms message part
Message part Preamble
4096 chips 10 ms (one radio frame)
Preamble Preamble
Message part Preamble
4096 chips 20 ms (two radio frames)
Preamble Preamble
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page32
PRACH Message Structure
Pilot
N bits
Slot # 0 Slot # 1 Slot # i Slot # 14
Message part radio frame T = 10 ms
T slot = 2560 chips, 10*2
Pilot
TFCI
N bits TFCI
Data
N data
bits Data
Control
k bits (k=0..3)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page33
PRACH Access Timeslot Structure
#1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14
5120 chips
radio frame: 10 ms radio frame: 10 ms
Access slot #0 Random Access Transmission
Access slot #1
Access slot #7
Access slot #14
Random Access Transmission
Random Access Transmission
Random Access Transmission Access slot #8
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page34
Acquisition Indicator Channel (AICH)
Carrying the Acquisition Indicators (AI), SF = 256
There are 16 kinds of Signature to generate AI
AS #14 AS #0 AS #1 AS #i AS #14 AS #0
a1 a2 a0 a31 a32 a30 a33 a38 a39
AI part Unused part
20 ms
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page35
Uplink Dedicated Physical Channel (DPDCH&DPCCH)
Uplink DPDCH and DPCCH are I/Q code division
multiplexed (CDM) within each radio frame
DPDCH carries data generated at Layer 2 and higher layer,
the OVSF code is Cch,SF,SF/4, where SF is from 256 to 4
DPCCH carries control information generated at Layer 1,
the OVSF code is Cch,256,0
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page36
Uplink Dedicated Physical Channel (DPDCH&DPCCH)
Frame Structure of Uplink DPDCH/DPCCH
Pilot Npilot bits
TPC NTPC bits
Data Ndata bits
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 10*2k bits (k=0..6)
1 radio frame: Tf = 10 ms
DPDCH
DPCCH FBI
NFBI bits TFCI
NTFCI bits
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page37
Downlink Dedicated Physical Channel (DPDCH+DPCCH)
Downlink DPDCH and DPCCH is time division multiplexing
(TDM).
DPDCH carries data generated at Layer 2 and higher layer
DPCCH carries control information generated at Layer 1
SF of downlink DPCH is from 512 to 4
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page38
Downlink Dedicated Physical Channel (DPDCH+DPCCH)
Frame Structure of Downlink DPCH (DPDCH+DPCCH)
One radio frame, Tf = 10 ms
Slot #0 Slot #1 Slot #i Slot #14
Tslot = 2560 chips, 20*2k bits (k=-1..6)
Data2
Ndata2 bits
DPDCH
TFCI
NTFCI bits
Pilot
Npilot bits
Data1
Ndata1 bits
DPDCH DPCCH DPCCH
TPC
NTPC bits
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page39
High-Speed Physical Downlink Shared Channel (HS-PDSCH) Bearing service data and layer 2 overhead bits mapped from
the transport channel
SF=16, can be configured several channels to increase data
service
Slot #0 Slot#1 Slot #2
Tslot = 2560 chips, M*10*2k bits (k=4)
Data Ndata1 bits
1 subframe: Tf = 2 ms
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page40
High-Speed Shared Control Channel (HS-SCCH)
Carries physical layer signalling to a single UE ,such as modulation
scheme (1 bit) ,channelization code set (7 bit), transport block size
(6bit),HARQ process number (3bit), redundancy version (3bit), new
data indicator (1bit), UE identity (16bit)
HS-SCCH is a fixed rate (60 kbps, SF=128) downlink physical channel
used to carry downlink signalling related to HS-DSCH transmission
Slot #0 Slot#1 Slot #2
Tslot = 2560 chips, 40 bits
Data Ndata1 bits
1 subframe: Tf = 2 ms
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page41
High-Speed Dedicated Physical Control Channel (HS-DPCCH )
Carrying information to acknowledge downlink transport
blocks and feedback information to the system for scheduling
and link adaptation of transport block
CQI and ACK/NACK
Physical Channel, Uplink, SF=256
Subframe #0 Subframe #i Subframe #n
One HS-DPCCH subframe ( 2ms )
ACK/NACK
1 radio frame: Tf = 10 ms
CQI
Tslot = 2560 chips 2 Tslot = 5120 chips
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page42
Contents
2. Physical Channels
2.1 Physical Channel Structure and Functions
2.2 Channel Mapping
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page43
Mapping Between Channels Logical channels Transport channels Physical channels
BCCH BCH P-CCPCH
FACH S-CCPCH
PCCH PCH S-CCPCH
CCCH RACH PRACH
FACH S-CCPCH
CTCH FACH S-CCPCH
DCCH, DTCH DCH DPDCH
HS-DSCH HS-PDSCH
RACH, FACH PRACH, S-CCPCH
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page45
Contents
1. Physical Layer Overview
2. Physical Channels
3. Physical Layer Procedure
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page46
Synchronization Procedure - Cell Search
Frame synchronization &
Code Group Identification
Scrambling Code
Identification
UE uses SSC to find frame
synchronization and identify the code
group of the cell found in the first
step
UE determines the primary scrambling
code through correlation over the
PCPICH with all codes within the
identified group, and then detects the
P-CCPCH and reads BCH information。
Slot
Synchronization
UE uses PSC to acquire slot
synchronization to a cell
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page48
Random Access
Procedure
START
Choose a RACH sub channel from
available ones
Get available signatures
Set Preamble Retrans Max
Set Preamble_Initial_Power
Send a preamble
Check the corresponding AI
Increase message part power by
p-m based on preamble power
Set physical status to be RACH
message transmitted Set physical status to be Nack
on AICH received
Choose a access slot again
Counter> 0 & Preamble power
< maximum allowed power
Choose a signature and increase preamble transmit power
Set physical status to be Nack
on AICH received
Get negative AI
No AI
Report the physical status to MAC
END
Get positive AI
The counter of preamble retransmit
Subtract 1, Commanded preamble power
increased by Power Ramp Step
N
Y
Send the corresponding message part
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page50
Transmit Diversity Mode
Application of Tx diversity modes on downlink physical
channel Physical channel type Open loop mode Closed loop mode
TSTD STTD Mode 1 Mode 2
P-CCPCH – applied – –
SCH applied – – –
S-CCPCH – applied – –
DPCH – applied applied applied
PICH – applied – –
HS-PDSCH – applied applied –
HS-SCCH – applied – –
AICH – applied – –
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page51
Transmit Diversity - STTD
Space time block coding based transmit antenna diversity
(STTD)
4 consecutive bits b0, b1, b2, b3 using STTD coding
b0 b1 b2 b3 Antenna 1
Antenna 2 Channel bits
STTD encoded channel bits
for antenna 1 and antenna 2.
b0 b1 b2 b3
-b2 b3 b0 -b1
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page52
Transmit Diversity - TSTD
Time switching transmit diversity (TSTD) is used only on
SCH channel
Antenna 1
Antenna 2
i,0
i,1
acs i,14
Slot #0 Slot #1 Slot #14
i,2
acp
Slot #2
(Tx
OFF) (Tx
OFF)
(Tx
OFF)
(Tx
OFF)
(Tx
OFF) (Tx
OFF)
(Tx
OFF)
acp acp
acs acs
acp
acs (Tx
OFF)
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page53
Closed Loop Mode
Used in DPCH and HS-PDSCH
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page54
References
TS 25.104 UTRA (BS) FDD Radio Transmission and Reception
TS 25.201 Physical layer-general description
TS 25.211 Physical channels and mapping of transport channels onto physical
channels (FDD)
TS 25.212 Multiplexing and channel coding (FDD)
TS 25.213 Spreading and modulation (FDD)
TS 25.214 Physical layer procedures (FDD)
TS 25.308 UTRA High Speed Downlink Packet Access (HSDPA)
TR 25.877 High Speed Downlink Packet Access (HSDPA) - Iub/Iur Protocol
Aspects
TR 25.858 Physical layer aspects of UTRA High Speed Downlink Packet Access
Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved. Page55
This course mainly introduces the basic concept, key
technology and procedures of WCDMA physical layer.
These knowledge is very important for understanding Uu
interface and further study.
Summary
Thank you www.huawei.com