Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com) 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
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Transcript
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Module Contents
• Standardisation and frequency bands
• Main properties of UMTS Air Interface
• Overview of NSN Radio Resource Management (RRM)
• HSPA technology
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
IMT-2000 frequency allocations2200 MHz20001900 1950 2050 2100 21501850
JapanIMT-2000PHS IMT-2000
ITU
Mob
ile
Sate
llite
IMT-2000 IMT-2000
EuropeUMTS(FDD)DE
CT
UMTS
(TD
D)
GSM1800
UMTS
(TD
D)UMTS(FDD)
USA
PCS
unlic
ense
d
PCSPCS
UMTS
(TD
D)IM
T-20
00 (
TDD)
Mob
ile
Sate
llite
Mob
ile
Sate
llite
Mob
ile
Sate
llite
Mob
ile
Sate
llite
Mob
ile
Sate
llite
Mob
ile
Sate
llite
Mob
ile
Sate
llite
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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 MHzJapan
Not supported by RU10 RAN
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
• Spreading sequences have a different length• Processing gain depends on the user data rate
Processing Gain Examples
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Transmission Power
Frequency
5MHz
Power density
Time
High bit rate user
Low bit rate user
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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...
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Scrambling Codes & Multipath Propagation
Scrambling code C1
C 1+Δ 3
C1+Δ2C1+Δ1
C2
Scrambling code C2
UE has simultaneous connection to two cells (soft handover)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
RAKE Receiver
• Combination or multipath components and in DL also signals from different cells
Del
ay Δ
1Code usedfor the
connection
Rx
Output
Finger
t
Cell-1
Cell-1
Cell-1
Cell-2
Rx
Rx
Rx
Finger
Finger
Finger
Del
ay Δ
2
Del
ay Δ
3
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Channelisation code Scrambling code
Usage Uplink: Separation of physical data (DPDCH) and control channels (DPCCH) from same terminal
Downlink: Separation of downlink connections to different users within one cell
Uplink: Separation of mobile
Downlink: Separation of sectors (cells)
Length 4–256 chips (1.0–66.7 μs)
Downlink also 512 chips
Different bit rates by changing the length of the code
Uplink: (1) 10 ms = 38400 chips or (2) 66.7 μs = 256 chips
Option (2) can be used with advanced base station receivers
Downlink: 10 ms = 38400 chips
Number of codes Number of codes under one scrambling code = spreading factor
Uplink: 16.8 million
Downlink: 512
Code family Orthogonal Variable Spreading Factor Long 10 ms code: Gold code
Short code: Extended S(2) code family
Spreading Yes, increases transmission bandwidth No, does not affect transmission bandwidth
Channelisation and Scrambling Codes
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
• 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)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
• 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)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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 UE Users within one cell
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Uplink power control target
Minimise required UL received power minimised UL transmit power and interference
UE1 UE2
min(Prx1)
min(Prx2)&
About equal whenRb1 = Rb2
Target:
Ptx1
Ptx1
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
UL Outer LoopPower Control
Open Loop Power Control (Initial Access)
Closed Loop Power Control
RNCBS
MS
DL Outer LoopPower Control
Power Control types
BLER target
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
BS3Rec
eive
d si
gnal
stre
ngth
BS3Distance from BS1
Threshold
Soft handover
BS2
BS1
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Hard handover
Hard handovers are typically performed between WCDMA frequencies and between WCDMA and GSM cells
GSM/GPRSGSM/GPRSGSM/GPRSGSM/GPRS
f1f1
f2f2
f1f1
f2f2f2f2f2f2
Inter-System handovers (ISHO)
Inter-Frequency handovers (IFHO)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Module Contents
• Standardisation and frequency bands
• Main properties of UMTS Air Interface
• Overview of NSN Radio Resource Management (RRM)
• HSPA technology
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Module Contents
HSPA technology
• Channel types• Physical Channels• Principle of HSPA
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Node BU
plin
kan
d Do
wnl
ink
Dedi
cate
dCh
anne
ls
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 interferenceDownlink air-interface capacity defined by downlink transmit power capability
Cell_DCH
CS and PS services
Channel Types for User Plane Data (R99)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Dedi
cate
dCh
anne
ls
Cell_DCH
HSD
PA
PS services CS services continue to use R99 dedicated channels
Channel Types for User Plane Data (R5)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
HSU
PA
Cell_DCH
HSD
PA
PS services CS services continue to use R99 dedicated channels
Channel Types for User Plane Data (R6)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Module Contents
HSPA technology• Channel types
• Physical Channels• Principle of HSPA
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Node B
DP
DC
HD
PC
CH
UL CHANNELSDPCH includes
• DPDCH• DPCCH – Pilot, TFCI, FBI, TPC
DPDCH encapsulates• Signalling radio bearers• User plane radio bearers
DL CHANNELSDPCH 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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
scheme, transport block size, HARQ process, redundancy and constellation version, new data indicator, UE identity
Physical Channels for Rel6 HSPA UE (DL)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
Module Contents
HSPA technology• Channel types• Physical Channels
• Principle of HSPA
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
HSxPA Motivation and General PrincipleImproved 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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
HSDPA Overview
15 CodeShared
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
• 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 powerThe 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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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 used means more than 1 users per TTI are using
• 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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
HS-PDSCHHS-PDSCHHS-PDSCHHS-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-PDSCHHS-PDSCHHS-PDSCHHS-PDSCH
HS-PDSCH
HS-SCCH
HS-SCCH
cat 6 cat 6 cat 6cat 8
HS-SCCH
HS-PDSCHHS-PDSCHHS-PDSCHHS-PDSCHHS-PDSCH
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
HSUPA Overview
TTI = 10 ms1-4 CodeMulti-Code
transmission
FastPower Control
Hybrid ARQwith incr. redundancy
NodeBControlledScheduling
BenefitHigher Uplink Peak rates: 2.0 Mbps
Higher Capacity: +50-100%Reduced Latency: ~50-75 ms
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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
Fast power control
HSUPA is like “reversed HSDPA”, except
Fast power control NoNo YesYes
SchedulingScheduling Point tomultipointPoint to
multipoint Multipoint to point
Multipoint to point
Non-scheduled transmission
Non-scheduled transmission NoNo Yes, for minimum/
guaranteed bit rateYes, 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)
Prepared by Sanjay Gohel, Teleysia Networks Pvt. Ltd. ( www.teleysia.com)
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