01. WCDMA Fundamentals
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Transcript of 01. WCDMA Fundamentals
1 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
WCDMA Fundamentals3GRPESS – MODULE 1
2 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Module 1 – WCDMA Fundamentals
Objectives
• After this module the participant shall be able to:-
• Understand the main cellular standards and allocated frequency bands
• Understand the main properties of WCDMA air interface including HSPA technology
• Recognize the main NSN RRM functions and their main tasks
3 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Module Contents
• Standardisation and frequency bands
• Main properties of UMTS Air Interface
• Overview of NSN Radio Resource Management (RRM)
• HSPA technology
4 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Module Contents
• Standardisation and frequency bands– Standardisation of 3G cellular networks
– IMT-2000 frequency allocations
– UMTS – FDD Frequency band evolution
• Main properties of UMTS Air Interface
• Overview of NSN Radio Resource Management (RRM)
• HSPA technology
5 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Standardisation of 3G cellular networks
• ITU (Global guidelines and recommendations)– IMT-2000: Global standard for third generation (3G) wireless communications
• 3GPP is a co-operation between standardisation bodiesETSI (Europe), ARIB/TTC (Japan), CCSA (China), ATIS (North America) and TTA (South Korea)
– GSM▪ EDGE
– UMTS▪ WCDMA - FDD
▪ WCDMA - TDD
– TD-SCDMA
• 3GPP2 is a co-operation between standardisation bodiesARIB/TTC (Japan), CCSA (China), TIA (North America) and TTA (South Korea)
– CDMA2000▪ CDMA2000 1x
▪ CDMA2000 1xEV-DO
6 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
IMT-2000 frequency allocations
2200 MHz20001900 1950 2050 2100 21501850
JapanIMT-2000
PH
S
IMT-2000
ITU
Mob
ile
Sate
llit
eIMT-2000 IMT-2000
EuropeUMTS(FDD)D
EC
T
UM
TS
(T
DD
)
GSM1800 U
MTS
(T
DD
)UMTS(FDD)
USA
PC
S
un
licen
sed
PCSPCS
UM
TS
(T
DD
)IM
T-2
00
0
(TD
D)
Mob
ile
Sate
llit
e
Mob
ile
Sate
llit
e
Mob
ile
Sate
llit
e
Mob
ile
Sate
llit
e
Mob
ile
Sate
llit
e
Mob
ile
Sate
llit
e
Mob
ile
Sate
llit
e
7 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
UMTS – FDD Frequency band evolution
• Release 99– I 1920 – 1980 MHz 2110 –2170 MHz UMTS only in Europe,
Japan– II 1850 –1910 MHz 1930 –1990 MHz US PCS, GSM1900
• New in Release 5– III 1710-1785 MHz 1805-1880 MHz GSM1800
• New in Release 6– IV 1710-1755 MHz 2110-2155 MHz US 2.1 GHz band– V 824-849MHz 869-894MHz US cellular, GSM850– VI 830-840 MHz 875-885 MHz Japan
• New in Release 7– VII 2500-2570 MHz 2620-2690 MHz– VIII 880-915 MHz 925-960 MHz GSM900– IX 1749.9-1784.9 MHz 1844.9-1879.9 MHz Japan
Not supported by RU10 RAN
8 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Module Contents
• Standardisation and frequency bands
• Main properties of UMTS Air Interface– UMTS Air interface technologies
– WCDMA – FDD
– WCDMA vs. GSM
– CDMA principle
– Processing gain
– WCDMA codes and bit rates
• Overview of NSN Radio Resource Management (RRM)
• HSPA technology
9 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
UMTS Air Interface technologies
• UMTS Air interface is built based on two technological solutions– WCDMA – FDD
– WCDMA – TDD
• WCDMA – FDD is the more widely used solution– FDD: Separate UL and DL frequency band
• WCDMA – TDD technology is currently used in limited number of networks
– TDD: UL and DL separated by time, utilizing same frequency
• Both technologies have own dedicated frequency bands
• This course concentrates on design principles of WCDMA – FDD solution, basic planning principles apply to both technologies
10 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
WCDMA – FDD technology
• Multiple access technology is wideband CDMA (WCDMA)– All cells at same carrier frequency
– Spreading codes used to separate cells and users
– Signal bandwidth 3.84 MHz
• Multiple carriers can be used to increase capacity– Inter-Frequency functionality to support mobility between frequencies
• Compatibility with GSM technology– Inter-System functionality to support mobility between GSM and UMTS
11 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
WCDMA Technology
5 M Hz
3.84 M Hz
f
5+5 MHz in FDD mode5 MHz in TDD mode
Freq
uenc
y
TimeDirect Sequence (DS) CDMA
WCDMA Carrier
WCDMAWCDMA5 MHz, 1 carrier5 MHz, 1 carrier
TDMA (GSM)TDMA (GSM)5 MHz, 25 carriers5 MHz, 25 carriers
Users share same time and frequency
12 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
UMTS & GSM Network Planning
GSM900/1800: 3G (W CDM A):
13 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Differences between WCDMA & GSM
WCDMA GSM
Carrier spacing 5 MHz 200 kHz
Frequency reuse factor 1 1–18
Power 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
Services withDifferent quality
requirements
Efficient packet data
14 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Multiple WCDMA carriers – Layered network
F1
F2
F2
F3
F3
F3
Micro BTSMacro BTS
Pico BTSs
1 - 10 km
50 - 100 m200 - 500 m
15 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Spreading Code
Spread Signal
Data
Air Interface
Bits (In this drawing, 1 bit = 8 Chips SF=8)
Baseband Data
-1
+1
+1
+1
+1
+1
-1
-1
-1
-1
ChipChip
Despreading
Despreading
CDMA principle - Chips & Bits & Symbols
16 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Energy Box
Frequ
ency
Ban
d
Duration (t = 1/Rb)
Po
wer
/Hz
Originating Bit Received BitEnergy per bit = Eb = const
Higher spreading factor Wider frequency band Lower power spectral density
BUT
Same Energy per Bit
17 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
FrequencyPow
er d
ensi
ty (
Wat
ts/H
z)
Unspread narrowband signal Spread wideband signal
Bandwidth W (3.84 Mchip/sec)
User bit rate R
sec84.3 MchipconstW
R
WdBGp Processing gain:
Spreading & Processing Gain
18 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Frequency (Hz)
Voice user (R=12,2 kbit/s)
Packet data user (R=384 kbit/s)
Pow
er
den
sity
(W
/Hz)
R
Frequency (Hz)
Gp=W/R=24.98 dB
Pow
er
den
sity
(W
/Hz)
R
Gp=W/R=10 dB
• Spreading sequences have a different length• Processing gain depends on the user data rate
Processing Gain Examples
19 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Transmission Power
Frequency
5MHz
Power density
Time
High bit rate user
Low bit rate user
20 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
WCDMA Codes
• In WCDMA two separate codes are used in the spreading operation
– Channelisation code
– Scrambling code
• Channelisation code– DL: separates physical channels of different users and common channels,
defines physical channel bit rate
– UL: separates physical channels of one user, defines physical channel bit rate
• Scrambling code– DL: separates cells in same carrier frequency
– UL: separates users
21 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
DL Spreading and Multiplexing in WCDMA
User 3
User 2
User 1
BCCH
Pilot X
CODE 1
X
CODE 2
X
CODE 3
X
CODE 4
X
CODE 5
+
X
SCRAMBLINGCODE
RF
SUM
User 2
User 1
BCCH
Pilot
Radio frame = 15 time slots
Time
User 3
3.84 MHzRF carrier
3.84 MHz bandwidth
CHANNELISATION codes:
P-CPICH
P-CCPCH
DPCH1
DPCH2
DPCH3
22 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
DL & UL Channelisation Codes
• Walsh-Hadamard codes: orthogonal variable spreading factor codes (OVSF codes)
– SF for the DL transmission in FDD mode = {4, 8, 16, 32, 64, 128, 256, 512}
– SF for the UL transmission in FDD mode = {4, 8, 16, 32, 64, 128, 256}
• Good orthogonality properties: cross correlation value for each code pair in the code set equals 0
– In theoretical environment users of one cell do not interfere each other in DL
– In practical multipath environment orthogonality is partly lost Interference between users of same cell
• Orthogonal codes are suited for channel separation, where synchronisation between different channels can be guaranteed
– Downlink channels under one cell
– Uplink channels from a single user
• Orthogonal codes have bad auto correlation properties and thus not suited in an asynchronous environment
– Scrambling code required to separate signals between cells in DL and users in UL
23 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Channelisation Code Tree
C0(0)=[1]
C2(1)=[1-1]
C2(0)=[11]
C4(0)=[1111]
C4(1)=[11-1-1]
C4(2)=[1-11-1]
C4(3)=[1-1-11]
C8(0)=[11111111]
C8(1)=[1111-1-1-1-1]
C8(2)=[11-1-111-1-1]
C8(3)=[11-1-1-1-111]
C8(0)=[1-11-11-11-1]
C8(5)=[1-11-1-11-11]
C8(6)=[1-1-111-1-11]
C8(7)=[1-1-11-111-1]
C16(0)=[............]C16(1)=[............]
C16(15)=[...........]
C16(14)=[...........]
C16(13=[...........]
C16(12)=[...........]
C16(11)=[...........]
C16(10)=[...........]
C16(9)=[............]
C16(8)=[............]
C16(7)=[............]
C16(6)=[............]
C16(5)=[............]
C16(4)=[............]
C16(3)=[............]
C16(2)=[............]
SF=1
SF=2
SF=4
SF=8
SF=16
SF=256
SF=512
...
24 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Half rate speechFull rate speech
128 kbps384 kbps
2 Mbps
Symbolphyb RR 2_SF
WRSymbol
(QPSK modulation)
Physical Layer Bit Rates (DL)
25 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Physical Layer Bit Rates (DL) - HSDPA
• 3GPP Release 5 standards introduced enhanced DL bit rates with High Speed Downlink Packet Access (HSDPA) technology
– Shared high bit rate channel between users – High peak bit rates
– Simultaneous usage of up to 15 DL channelisation codes (In HSDPA SF=16)
– Higher order modulation scheme (16-QAM) Higher bit rate in same band▪ 16-QAM provides 4 bits per symbol 960 kbit/s / code physical channel peak
rate
Coding rateCoding rate
QPSKQPSK
Coding rateCoding rate
1/41/4
2/42/4
3/43/4
5 codes5 codes 10 codes10 codes 15 codes15 codes
600 kbps600 kbps 1.2 Mbps1.2 Mbps 1.8 Mbps1.8 Mbps
1.2 Mbps1.2 Mbps 2.4 Mbps2.4 Mbps 3.6 Mbps3.6 Mbps
1.8 Mbps1.8 Mbps 3.6 Mbps3.6 Mbps 5.4 Mbps5.4 Mbps
16QAM16QAM
2/42/4
3/43/4
4/44/4
2.4 Mbps2.4 Mbps 4.8 Mbps4.8 Mbps 7.2 Mbps7.2 Mbps
3.6 Mbps3.6 Mbps 7.2 Mbps7.2 Mbps 10.7 Mbps10.7 Mbps
4.8 Mbps4.8 Mbps 9.6 Mbps9.6 Mbps 14.4 Mbps14.4 Mbps
HSDPA
26 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Physical Layer Bit Rates (UL) - HSUPA
• 3GPP Release 6 standards introduced enhanced UL bit rates with High Speed Downlink Packet Access (HSUPA) technology
– Fast allocation of available UL capacity for users – High peak bit rates
– Simultaneous usage of up to 2+2 UL channelisation codes (In HSUPA SF=2 – 4)
Coding rateCoding rate
1/21/2
3/43/4
4/44/4
1 x SF41 x SF4 2 x SF42 x SF4 2 x SF22 x SF2 2 x SF2 + 2 x SF4
2 x SF2 + 2 x SF4
480 kbps480 kbps 960 kbps960 kbps 1.92 Mbps1.92 Mbps 2.88 Mbps2.88 Mbps
720 kbps720 kbps 1.46 Mbps1.46 Mbps 2.88 Mbps2.88 Mbps 4.32 Mbps4.32 Mbps
960 kbps960 kbps 1.92 Mbps1.92 Mbps 3.84 Mbps3.84 Mbps 5.76 Mbps5.76 Mbps
27 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
DL & UL Scrambling Codes
DL Scrambling Codes
• Pseudo noise codes used for cell separation– 512 Primary Scrambling Codes
UL Scrambling Codes
• Two different types of UL scrambling codes are generated– Long scrambling codes of length of 38 400 chips = 10 ms radio frame
– Short scrambling codes of length of 256 chips are periodically repeated to get the scrambling code of the frame length
▪ Short codes enable advanced receiver structures in future
28 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Scrambling Codes & Multipath Propagation
Scrambling code C1
Scrambling code C2
C 1+ 3
C1+2C1+
1
C2
UE has simultaneous connection to two cells (soft handover)
29 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
RAKE Receiver
• Combination or multipath components and in DL also signals from different cells
Del
ay
1Code used
for theconnection
Rx
Output
Finger
t
Cell-1
Cell-1
Cell-1
Cell-2
Rx
Rx
Rx
Finger
Finger
Finger
Del
ay
2
Del
ay
3
30 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Channelisation and Scrambling Codes
31 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Module Contents
• Standardisation and frequency bands
• Main properties of UMTS Air Interface
• Overview of NSN Radio Resource Management (RRM)– Load control
– Admission Control
– Packet Scheduler
– Resource Manager
– Power Control
– Handover Control
• HSPA technology
32 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Radio Resource Management
• RRM is responsible for optimal utilisation of the radio resources:– Transmission power and interference
– Logical codes
• The trade-off between capacity, coverage and quality is done all the time
– Minimum required quality for each user (nothing less and nothing more) Maximum number of users
• The radio resources are continuously monitored and optimised by several RRM functionalities service quality
cell coverage cell capacity
Optimizationand Tailoring
33 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
RRM Functionalities
LC Load Control
AC Admission Control
PS Packet Scheduler
RM Resource Manager
PC Power Control
HC HO Control
PC
HCFor each connection/user
LC
AC
For each cell
PS
RM
34 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
• LC performs the function of load control in association with AC & PS
• LC updates load status using measurements & estimations provided by AC and PS
• Continuously feeds cell load information to PS and AC;
– Interference levels (UL)
– BTS power level (DL)
LC
AC
PSNRT load
Load change info
Load status
Load Control (LC)
35 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Load Control – Load Status
• Load thresholds set by radio network planning parameters
Overloadthreshold x
Load Targetthreshold y
Pow
er
Time
Load Margin
Overload
Normal load
Measured loadFree capacity
36 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
• Checks that admitting a new user will not sacrifice planned coverage or quality of existing connections
• Admission control handles three main tasks– Admission decision of new connections
▪ Take into account current load conditions (from LC) and load increase by the new connection
▪ Real-time higher priority than non-real time
▪ In overload conditions new connections may be rejected
– Connection QoS definition▪ Bit rate, BER target etc.
– Connection specific power allocation (Initial, maximum and minimum power)
Admission Control (AC)
37 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Packet Scheduler (PS)
• PS allocates available capacity after real-time (RT) connections to non-real time (NRT) connections
– Each cell separately
– Based on QoS priority level of the connection
– In overload conditions bit rates of NRT connections decreased
• PS selects allocated channel type (common, dedicated or HSPA)
• PS relies on up-to-date information from AC and LC
• Capacity allocated on a needs basis using ‘best effort’ approach– RT higher priority
38 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Resource Manager (RM)
• Responsible for managing the logical radio resources of the RNC in co-operation with AC and PS
• On request for resources, from either AC(RT) or PS(NRT), RM allocates:
– DL spreading code
– UL scrambling code
Code Type Uplink Downlink
Scrambling codes
Spreading codes
User separation Cell separation
Data & control channels from same UEUsers within one cell
39 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Power control (PC) in WCDMA
• Fast, accurate power control is of utmost importance – particularly in UL;
– UEs transmit continuously on same frequency Always interference between users
– Poor PC leads to increased interference reduced capacity
• Every UE accessing network increases interference– PC target to minimise the interference Minimize transmit power of each
link while still maintaining the link quality (BER)
• Mitigates 'near far effect‘ in UL by providing minimum required power for each connection
• Power control has to be fast enough to follow changes in propagation conditions (fading)
– Step up/down 1500 times/second
40 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Uplink power control target
Minimise required UL received power minimised UL transmit power and interference
UE1 UE2
min(Prx1)
min(Prx2)
&
About equal when
Rb1 = Rb2
Target:
Ptx1
Ptx1
41 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Power Control types
• Power control functionality can be divided to three main types
• Open loop power control– Initial power calculation based on DL pilot level/pathloss measurement by UE
• Outer (closed) loop power control– Connection quality measurement (BER, BLER) and comparison to QoS target
– RF quality target (SIR target) setting for fast closed loop PC based on connection quality
• Fast closed loop power control– Radio link RF quality (SIR) measurement and comparison to RF quality target
(SIR target)
– Power control command transmission based on RF quality evaluation
– Change of transmit power according to received power control command
42 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
UL Outer LoopPower Control
Open Loop Power Control (Initial Access)
Closed Loop Power Control
RNC
BS
MS
DL Outer LoopPower Control
Power Control types
BLER target
43 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Power control in HSPA
• In HSDPA (DL) the transmit power from base station is kept constant and the signal modulation and coding is adapted according to the channel conditions
– 2 ms interval 500 Hz
• In HSUPA (UL)– The power control of HSUPA channels in UL utilises both
▪ Fast closed loop power control
▪ Outer loop power control
– Both work according to similar principles as the R99 power control
44 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Handover Control (HC)
• HC is responsible for:– Managing the mobility aspects of an RRC connection as UE moves around the
network coverage area
– Maintaining high capacity by ensuring UE is always served by strongest cell
• Soft handover– MS handover between different base stations
• Softer handover– MS handover within one base station but between different sectors
• Hard handover– MS handover between different frequencies or between WCDMA and GSM
45 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Soft/softer handover
• UE is simultaneously connected to 2 to 3 cells during soft handover
• Soft handover is performed based on UE cell pilot power measurements and handover thresholds set by radio network planning parameters
• Radio link performance is improved during soft handover
• Soft handover consumes base station and transmission resources
BS1
BS2
BS3
Rec
eive
d s
ign
al s
tren
gth
BS3
Distance from BS1
Threshold
Soft handover
BS2
BS1
46 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Hard handover
Hard handovers are typically performed between WCDMA frequencies and between WCDMA and GSM cells
GSM/GPRSGSM/GPRSGSM/GPRSGSM/GPRS
f1f1
f2f2
f1f1
f2f2f2
f2f2f2
Inter-System handovers (ISHO)
Inter-Frequency handovers (IFHO)
47 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Module Contents
• Standardisation and frequency bands
• Main properties of UMTS Air Interface
• Overview of NSN Radio Resource Management (RRM)
• HSPA technology
48 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Module Contents
HSPA technology
• Channel types• Physical Channels
• Principle of HSPA
49 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Node BU
plin
k an
d D
ownl
ink
Ded
icat
ed C
hann
els
The introduction of 3G made use of uplink and downlink dedicated channels to transfer user plane and control plane data in CELL_DCH
Applicable to
• All 3GPP Releases
Uplink air-interface capacity defined by maximum planned increase in uplink interference
Downlink air-interface capacity defined by downlink transmit power capability
Cell_DCH
CS and PS services
Channel Types for User Plane Data (R99)
50 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Node B
In R5 3G evolved to include HSDPA for transferring packet switched user plane data in the downlink direction
Applicable to
• 3GPP Release 05
• NSN RAS05, RAS05.1
HSDPA makes use of a downlink transmit power allocation and so has a direct impact upon downlink capacity
The resource shared between multiple HSDPA users is the HSDPA downlink transmit power
The Node B scheduler assigns timeslots & codes to specific UE to allow access to the HSDPA downlink transmit power
Upl
ink
Ded
icat
ed
Cha
nnel
s
Cell_DCH
HS
DP
A
PS services CS services continue to use R99 dedicated channels
Channel Types for User Plane Data (R5)
51 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Node B
• 3G has further evolved to include HSUPA for transferring packet switched user plane data in the uplink direction
• Applicable to
– 3GPP Release 06
– NSN RAS06, RU10
• HSUPA makes use of a uplink interference allocation and so has a direct impact upon uplink capacity
• The resource shared between multiple HSUPA users is the uplink interference
• The Node B scheduler assigns transmit power ratios to specific UE to allow a contribution towards the total increase in uplink interference
HS
UP
A
Cell_DCH
HS
DP
A
PS services CS services continue to use R99 dedicated channels
Channel Types for User Plane Data (R6)
52 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Module Contents
HSPA technology
• Channel types
• Physical Channels• Principle of HSPA
53 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Node B
DP
DC
HD
PC
CH
UL CHANNELS
DPCH includes• DPDCH• DPCCH – Pilot, TFCI, FBI, TPC
DPDCH encapsulates• Signalling radio bearers• User plane radio bearers
DL CHANNELS
DPCH includes• DPDCH• DPCCH - Pilot, TFCI, TPC
DPDCH encapsulates• Signalling radio bearers• User plane radio bearers
DP
DC
HD
PC
CH
R99 DPCH
Dedicated
Physical Channels for R99 UE
54 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Node B
UL CHANNELS
DPCH includes• DPDCH• DPCCH – Pilot, TFCI, FBI, TPC• HS-DPCCH – CQI, ACK/NACK
DPDCH encapsulates• Signalling radio bearers• User plane radio bearers
DL CHANNELS
DPCH includes• DPDCH• DPCCH - Pilot, TFCI, TPC
DPDCH encapsulates• Signalling radio bearers
HS-PDSCH encapsulates• User plane radio bearers
HS-SCCH provides• Channelisation code set, modulation scheme,
transport block size, HARQ process, redundancy and constellation version, new data indicator, UE identity
1-15
x H
S-P
DS
CH
1-4
x H
S-S
CC
H
DP
DC
HD
PC
CH
HS
-DP
CC
H
DP
DC
HD
PC
CH
HSDPAAssociated DPCH
Dedicated Common
Physical Channels for Rel5 / Rel6 HSDPA UE
55 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Node B
1-15
x H
S-P
DS
CH
1-4
x H
S-S
CC
H
DP
DC
HD
PC
CH
HS
-DP
CC
H1,
2,4
x E
-DP
DC
HE
-DP
CC
H
F-D
PC
H
Dedicated Common
E-D
CH
RG
CH
E-D
CH
AG
CH
E-D
CH
HIC
H
UL CHANNELS
E-DPCH includes• E-DPDCH• E-DPCCH – E-TFCI, RSN, Happy Bit
DPCH includes• DPDCH• DPCCH – Pilot, TFCI, FBI, TPC• HS-DPCCH – CQI, ACK/NACK
E-DPDCH encapsulates• User plane radio bearers
DPDCH encapsulates• Signalling radio bearers
Physical Channels for Rel6 HSPA UE (UL)
56 © NSN Siemens Networks 3G Radio Planning Essentials / NPO Capability Development
Node B
1-15
x H
S-P
DS
CH
1-3
x H
S-S
CC
H
DP
DC
HD
PC
CH
HS
-DP
CC
H1,
2,4
x E
-DP
DC
HE
-DP
CC
H
F-D
PC
H
Dedicated Common
E-D
CH
RG
CH
E-D
CH
AG
CH
E-D
CH
HIC
H
DL CHANNELS
DPCH includes• F-DPCH – TPC• E-DCH RGCH• E-DCH HICH
E-DCH AGCH encapsulates• Absolute grant value, absolute grant scope
HS-PDSCH encapsulates• User plane radio bearers
HS-SCCH provides• Channelisation code set, modulation
scheme, transport block size, HARQ process, redundancy and constellation version, new data indicator, UE identity
Physical Channels for Rel6 HSPA UE (DL)
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Module Contents
HSPA technology
• Channel types
• Physical Channels
• Principle of HSPA
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HSxPA Motivation and General Principle Improved performance and spectral efficiency in DL and UL by introducing a shared channel principle:
• Significant enchancement with peak rates up to 14.4 Mbps (28 Mbps in Rel7) in DL, and 2 Mbps (11.5 Mbps with 16QAM) in UL
• Huge capacity increase per site; no site pre-planning necessary
• Improved end user experience: reduced delay/latency, high response time
HSDPA (3GPP Rel5)
Fast pipe is shared among UEs
Scheduling A
,B,C
HSUPA (3GPP Rel6)
Dedicated pipe for every UE in ULPipe (codes and grants) changing with timeE-DCH scheduling
E-DCH -
A
E-DCH -
B
E-DCH -
C
Rel. 99
DCH -A
DCH -B
DCH -C
Dedicated pipe for every UE
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HSDPA Overview
15 Code Shared
transmission
16QAMModulation
TTI = 2 ms Hybrid ARQwith incr. redundancy
Fast Link Adaptation
AdvancedScheduling
BenefitHigher Downlink Peak rates: 14 Mbps
Higher Capacity: +100-200%Reduced Latency: ~75 ms
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• HSDPA power is limited by the PtxMaxHSDPA parameter
Cell maximum TX power
Common chs
HSDPA
Maximum HSDPA power (PtxMaxHSDPA)
Non-HSDPA power
Ptx
Time
Cell maximum TX power
Common chs
HSDPA
Non-HSDPA power
Ptx
Time
• HSDPA power is not limited, all available power can be allocated to HSDPA
• Still PtxMaxHSDPA can be used to limit
HS-PDSCH Transmit power
The Packet Scheduler is responsible for determining the transmission power on the HS-PDSCH channels• Dynamic HSDPA power allocation is always used in BTS
– HSDPA power can be limited with PtxMaxHSDPA• HSDPA Dynamic Resource Allocation feature is activated with RNC parameter
HSDPADynamicResourceAllocation
– Disabled: PtxMaxHSDPA sent to BTS and used to limit the maximum HSDPA power– Enabled: No power limitation sent to BTS, all available power allocated to HSDPA
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Maximum code allocation for HSDPA
SF=1
SF=2
SF=4
SF=8
SF=16
SF=32
SF=64
SF=128
SF=256
15 HS-PDSCH codes15 HS-PDSCH codes
Up to three HS-SCCH codesUp to three HS-SCCH codesCodes for common channels in the cellCodes for common channels in the cell
Codes for associated DCHs and non-HSDPA users
Codes for associated DCHs and non-HSDPA users
Used by 2 HSDPA UEs no SF256 available for the 3rd UE for
associated DCH
Used by AMR user only one SF128 code remains for associated
DCH
Used by HSDPA UE as associated DCH and HS-SCCH
Case1:
Case2:
Case1+2:
• Code tree limitation makes it hard to have 15 codes allocated for HSDPA– Still commonly 14 or 12 or lower amounts are easily available– Note that current terminals support only 10 codes so 15 codes means more than 1 users per TTI
• 15 codes is available but not commonly for cells where has reasonable high traffic (noticing terminal limitation 10 codes, thus fully utilise 15 codes needs minimum 2 HSDPA users)
– Case 1: Allocation of 15 is not possible when more than 2 HSDPA users are active (i.e. 3 HSDPA users)– Case 2: Allocation of 15 is not possible (with two HSDPA users) when 1 AMR12.2 user exists in the cell
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HSDPA - UE Categories
• QPSK and 16QAM modulation with multicode transmission used to achieve high data rates
• 12 different UE categories defined, categories are characterised by– Number of parallel codes supported
– Minimum inter-TTI interval
• Theoretical peak bit rate up to 14.4 Mbps for category 10 UE using 15 codes and 16QAM
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HS-PDSCHHS-PDSCHHS-PDSCH
HS-PDSCH
HSDPA Code Multiplexing
• With Code Multiplexing, maximum of three UEs can be scheduled during one TTI from single cell
• Multiple HS-SCCH channels (max 3 in RAS06)– One for each simultaneously receiving UE
• Available HS-PDSCH codes and HS-PDSCH power of cell are divided between UEs
• HS-PDSCH codes actually used depends on the channel conditions of a UE
• Important when cell supports more codes than UEs do
– Cell supports 15 HS-PDSCH codes, Cat6 and Cat8 UEs => 3 users can be scheduled on TTI
• BTS must also be capable of 10/15 codes in order to dynamically adjust HS-PDSCH codes
HS-PDSCH
cat 6
HS-PDSCH
HS-PDSCH
HS-PDSCH
HS-PDSCH
HS-PDSCH
HS-SCCH
HS-SCCH
cat 6 cat 6 cat 6cat 8
HS-SCCH
HS-PDSCH
HS-PDSCH
HS-PDSCHHS-PDSCH
HS-PDSCH
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HSUPA Overview
TTI = 10 ms1-4 Code Multi-Code
transmission
FastPower Control
Hybrid ARQwith incr. redundancy
NodeB ControlledScheduling
BenefitHigher Uplink Peak rates: 2.0 Mbps
Higher Capacity: +50-100%Reduced Latency: ~50-75 ms
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HSUPA - UE Categories
• BPSK modulation with multicode transmission used to achieve high data rates
• 6 different UE categories defined, categories are characterised by– Number of parallel codes supported
– Support of 2ms TTI - 10ms TTI supported by all the HSUPA UEs
• Theoretical peak bit rate up to 5.74 Mbps for category 6 UE using 2 ms TTI– No coding and no retransmissions - all bits must be delivered correctly over the air…
11484
20000
20000
5772
20000
14484
2798
14484
7110
Transport Block size
2 Mbps102 x SF24
2.89 Mbps22 x SF24
1.45 Mbps102 x SF42
1.40 Mbps22 x SF42
2 Mbps102xSF2 + 2xSF46
6
5
3
1
HSUPACategory
2
10
10
10
TTI
2xSF2 + 2xSF4
2 x SF2
2 x SF4
1 x SF4
Codes x Spreading
5.74 Mbps
2 Mbps
1.45 Mbps
0.71 Mbps
Data rate
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HSPA mobility
HSDPA
• Soft handover on associated DCH channels (signalling, UL data)
• Serving cell change for HSDPA data channel– Connected only to one cell at a time
HSUPA
• Soft handover utilised for uplink channels as required due to near-far problem
• Only Serving Cell can allocate more UL capacity/power
HS-SCCH
HS-PDSCH
DPCH
DPCHServing HS-DSCH cell
Notice that soft/softer handoveris not supported for HS-SCCH/HS-PDSCH
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UL DCH vs HSDPA vs HSUPA Concepts
HSDPAHSDPA HSUPAHSUPA
ModulationModulation QPSK and 16-QAMQPSK and 16-QAM BPSK and Dual-BPSKBPSK and Dual-BPSK
Soft handoverSoft handover NoNo YesYes
HSUPA is like “reversed HSDPA”, except
Fast power control
Fast power control NoNo YesYes
SchedulingScheduling Point tomultipoint
Point tomultipoint
Multipoint to point
Multipoint to point
Non-scheduled transmission
Non-scheduled transmission NoNo Yes, for minimum/
guaranteed bit rate
Yes, for minimum/guaranteed bit rate
Required for near-far avoidance
Efficient UE power amplifier
Scheduling cannot be as fast as in HSDPA
Similar to R99 DCH but with HARQ
HSUPA could be better described as Enhanced DCH in the uplink than “reversed HSDPA”
Feature
Variable spreading factor
Fast power control
Adaptive modulation
BTS based scheduling
DCH
Yes
Yes
No
No
HSUPA
Yes
Yes
No
Yes
Fast L1 HARQ No Yes
HSDPA
No
No
Yes
Yes
Yes
Multicode transmission Yes(No in practice)
Yes Yes
HSUPA (E-DCH) is an uplink DCH with BTS-based HARQ and scheduling and true multicode support
Soft handover Yes Yes No(associated DCH only)
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Module 1 – WCDMA Fundamentals
Summary
• Radio interface technology of UMTS is WCDMA with FDD and TDD versions
• WCDMA networks can be built on European, US-based and Asian/Japanese frequency bands
• WCDMA air interface utilises combination of two spreading codes
• Radio Resource Management is responsible of efficient utilisation of radio resources while offering required quality of service to users
• HSPA technology can provide higher air interface efficiency